Shifting surgical strategies for osteonecrosis of the femoral head: evidence from a nationwide Japanese database.

PurposeSmoking is a potentially modifiable risk factor for adverse outcomes after total hip arthroplasty (THA), but evidence on early postoperative complications in Asian populations remains limited. This study examined the association between smoking and early postoperative complications after elective THA using a nationwide inpatient database in Japan.MethodsThis retrospective cohort study analysed data from the Japanese Diagnosis Procedure Combination (DPC) database between December 2011 and March 2023. Patients undergoing elective primary THA for osteoarthritis, osteonecrosis of the femoral head, or rheumatoid arthritis were included. Smoking status was identified using administrative codes. One-to-one propensity score matching was used to balance baseline characteristics between smokers and non-smokers. Primary outcomes were early postoperative surgical complications, medical complications, and in-hospital mortality. Dose-dependent effects were assessed using the Brinkman Index, with heavy smoking defined as ≥ 600.ResultsAfter propensity score matching, 52,551 patients were included in each group. Smoking was associated with a higher risk of postoperative infection (odds ratio [OR] 1.31; 95% confidence interval [CI] 1.15–1.49; p < 0.001) and a lower likelihood of blood transfusion (OR 0.83; 95% CI 0.80–0.85; p < 0.001). No significant associations were observed with dislocation, periprosthetic fracture, wound dehiscence, reoperation, major medical complications, or in-hospital mortality. Heavy smoking (Brinkman Index ≥ 600) was not associated with postoperative complications.ConclusionsSmoking was associated with an increased risk of early postoperative infection following elective THA, but not with other major complications or in-hospital mortality. Smoking cessation should be considered an important component of perioperative optimisation.

Osteonecrosis of the femoral head (ONFH), also called avascular necrosis of the femoral head (AVN), is a common and often refractory disease in the orthopaedic domain. ONFH can be caused by trauma or other factors (nontraumatic). Traumatic ONFH is caused mainly by trauma to the hip, such as femoral neck fracture or hip dislocation. In China, the causes of nontraumatic ONFH are mainly corticosteroid treatment and/or alcohol abuse. ONFH is progressive and about 80% of necrotic femoral heads will collapse within 1 to 4 years in the absence of effective treatment. Collapse of the femoral head (manifested as subchondral fracture and a positive crescent sign) can progress to severe osteoarthritis requiring prosthetic replacement. Nontraumatic ONFH mainly affects young and middle-aged people and bilateral hip involvement is common (approximately 80%). Because the long-term efficacy of total hip arthroplasty in young and middle-aged patients is unpredictable, it is important to perform joint-preserving procedures in the early stages. Based on the suggestions of the Association Research Circulation Osseous (ARCO) and American Academy of Orthopaedic Surgeons, ONFH can be defined as a disease involving the femoral head and characterized by structural change, collapse and joint dysfunction resulting from necrosis caused by interruption or impairment of the blood supply to the femoral head, and subsequent repair of the bone cells and marrow. Based on the diagnostic criteria of the Japanese Investigation Committee and Mont, we propose that the following diagnostic criteria for ONFH are appropriate for China. Clinical symptoms, signs and history which include hip joint pain involving the inguinal region, buttocks and upper leg; limited and painful internal rotation of the hip joint; a history of hip trauma, corticosteroid application and/or alcohol abuse. Radiographic findings: (i) femoral head collapse without joint space narrowing; (ii) calcification band(s) with clear borders inside the femoral head; and (iii) lucent band(s) in subchondral bone (subchondral fracture or positive crescent sign). Radionuclide bone scanning shows a cold area within the hot area of the femoral head. Magnetic resonance imaging of the femoral head shows a banded low signal shadow (banded type) in T1 weighted images or a double-line sign in T2 weighted images. Bone biopsy shows empty osteocytic lacuna with multiple trabecular involvement in >50% of trabeculae as well as necrotic bone marrow. Radiographic findings: (i) femoral head collapse with narrowed joint space; (ii) cystic changes or spotted calcification inside the femoral head; and (iii) flattening of the lateral superior aspect of the femoral head. Radionuclide bone scanning shows a cold or hot area inside the femoral head. Magnetic resonance imaging of the femoral head shows homogenous or heterogeneous low intensity signals with banded changes in T1 weighted images. Two or more positive primary criteria are sufficient for a diagnosis of ONFH. One positive primary criterion with three positive secondary criteria, including at least one positive radiographic sign, are sufficient for a diagnosis of possible ONFH. Clinical examination: a detailed case history, including any hip trauma, consumption of corticosteroids, alcohol abuse and/or anemia, should be taken and clinical features, such as the site and characteristics of any pain and the relationship between pain and weight bearing, should be collected. The physical examination should include assessment of the rotation of the involved hip joint. Radiography: ONFH in its early phases (phases 0 and I) is difficult to identify by radiography. Positive radiographic findings for phase II or greater phases of ONFH include calcification bands, radiotransparent cystic changes, spotty calcification, subchondral fracture and femoral head collapse. The recommended views on radiography include the anteroposterior and frog lateral views, the latter allowing clearer visualization of a necrotic femoral head. Magnetic resonance scan: MR scan is the most reliable method for the diagnosis of early ONFH with a sensitivity and specificity of up to 96%–99%. Typical MRI findings in ONFH include a spirally banded low signal and/or low signal surrounding a region of high or heterogeneous signal at the proximal end of, or across, the residual bone marrow line of the involved femoral head in T1 weighted images. T2 weighted images show a typical double-line sign. Combined T1 and T2 weighted imaging is recommended, supplemented with fat-suppression or short T1 inversion recovery sequencing for a suspected lesion. Sagittal scanning should be used to supplement the routine employment of coronal or transverse scanning, because it allows more precise estimation of the volume of necrosis and visualization of the lesion. Gadolinium-enhanced MRI is superior for the diagnosis of early ONFH. Radionuclide bone scanning: radionuclide bone scanning has high sensitivity and low specificity for diagnosing early ONFH. A cold area within a hot area in a scan for which 99mTC was used is a characteristic manifestation of ONFH, but the presence of pure radionuclide aggregation (hot area) should be differentiated from other joint diseases. This method of examination can be used for screening for the disease at an early phase or for involvement of multiple sites. Single photon emission computer tomography increases the sensitivity rather than the specificity. Computed tomography scanning: CT scanning can clearly display the borders, area, calcified bands, autologous repair and subchondral fractures of ONFH in phases II and III, but is useless for ONFH in phase I. CT scanning surpasses MRI and radiography in displaying any subchondral fracture. A supplemented two-dimensional reconstruction can display the overall femoral head from a coronal view. CT scanning is a useful method for determining the severity of the lesion and the appropriate therapeutic regimen. Other investigations: positron emission tomography, 67Ga or sulfur colloid labeled radioisotope scanning and T2 dynamic MRI blood flow perfusion determination for the diagnosis of early ONFH are currently being testing prior to their clinical application. Moderate/severe osteoarthritis. Typical osteoarthritis is not difficult to differentiate from ONFH, but a slightly narrow joint space and subchondral cystic changes may lead to a misdiagnosis. This disease typically shows calcification and cystic change on CT scanning, low signals on MRI and bony outgrowths at the medial lower margin of the femoral head. Osteoarthritis secondary to acetabular dysplasia. This is not difficult to differentiate from ONFH because it has characteristic radiographic findings including shallow acetabulum, narrowed or absent joint space in the superior lateral region of the femoral head, bony calcification, cystic changes and changes in the corresponding acetabular region similar to the weight-bearing region of the femoral head. Ankylosing spondylitis-related hip arthritis. This is not difficult to identify because of the following typical clinical properties: common in young male patients, bilateral sacroiliac joint involvement, HLA-B27 (+) and a narrowed or absent joint space (or even joint fusion), with a femoral head that is still round. However, patients with a history of long-term corticosteroid administration may develop concomitant ONFH, presenting with a mild to moderate femoral head collapse. Rheumatoid arthritis. This is not difficult to identify on the basis of the following characteristics: a common disease in female patients, narrowed or absent joint space with a round femoral head, frequent subchondral erosion of the femoral head, cystic changes and acetabular erosion. Idiopathic transient osteoporosis of the hip (ITOH). This is caused by transient painful bone marrow edemaand is common in middle-aged people. Its radiographic findings are bone mass reduction at the femoral head, neck and even the trochanter. MRI shows homogenous low signals on T1 weighted images and high signals on T2 weighted images, ranging from the neck to the trochanter of the femoral head, without the banded low signal changes that are seen in ONFH. ITOH can spontaneously resolve 3–6 months after onset. Subchondral incomplete fracture. Clinical features include: common in patients aged more than 60 years, absence of a trauma history, sudden onset of hip pain, walking difficulties and restricted joint movement. Radiography shows slight flattening of the superior lateral aspect of the femoral head. MRI shows subchondral low signals and edema of the surrounding bone marrow on T1 and T2 weighted images, and flaky high signals on T2 fat-suppression images. This fracture is a fracture of tiny trabeculae secondary to osteoporosis. Pigmented villonodular synovitis. This involves the knee joints more often than the hip joints. The features of hip pigmented villonodular synovitis include common in young people, mild to moderate hip pain with claudication and mild restriction of joint movement in the early and middle stages and severe restriction of joint movement in the advanced stage. CT scanning and radiography show cortical erosion at the femoral head, neck and/or acetabulum and mild to moderate narrowing of the joint space. MRI shows extensive synovial hypertrophy involving the overall joint with well distributed low to moderate intensity signals. Femoral head bruise. This is characterized by a hip trauma history, hip pain and claudication. MRI shows moderate intensity signals inside the femoral head on T1 weighted images and high intensity signals on T2 weighted images, more often on the medial side of the femoral head. Synovial herniation pit. This is a benign disease characterized by invasion of hyperplastic synovial tissue into the cortex of the femoral neck. MRI shows low signals on T1 weighted images and small round lesions with high signals on T2 weighted images. It is commonly manifested as asymptomatic erosion of the the cortex in the superior region of the femoral neck. Once ONFH has been diagnosed, scientific staging should be undertaken. This is very helpful for selecting an appropriate treatment plan, accurately assessing the prognosis, and comparing the effects of treatment. We recommend the following staging methods: ARCO staging (Table 1), Steinberg staging (Table 2) and Ficat staging (Table 3). An appropriate treatment strategy should be selected according to the stage, volume of osteonecrosis, age, joint function and occupation of the patient. Currently, there is no single method for managing all variations of ONFH regardless of type, stage and necrotic volume. The treatment methods for ONFH are both non-surgical and surgical and each has its own indications. Whether weight bearing with protection can prevent collapse of the femoral head is controversial. Weight-bearing with crutches is recommended to reduce the pain, whereas use of a wheelchair is not recommended. This is suitable for the pre-collapse stage of ONFH (ARCO Stages 0, I, II) and includes non-steroidal anti-inflammatory analgesics, low molecular weight heparin, Chinese medicine for treating thrombophilia or hypofibrinolysis, alendronate for preventing collapse of the femoral head, vasodilator drugs and drugs for elimination of bone marrow edema. These include extracorporeal shock wave and high-frequency magnetic field therapy. All these methods are useful for alleviating pain and promoting recovery of necrotic bone. The procedures include joint-preservation and joint-replacement surgery. This utilizes the procedures of core decompression, bone grafting, and osteotomy and is suitable for ONFH in ARCO Stages I, II, and IIIA. If the procedure is selected appropriately, it is possible to avoid or delay joint replacement. Core decompression surgery has a long history and recognized benefits in the treatment of ONFH ARCO Stages I and II. It is recommended that a 3-mm wire be used to produce multiple holes under fluoroscopic control in combination with autologous bone marrow cell transplantation or bone morphogenetic protein. This is not recommended for advanced stages (ARCO Stages III and IV). Common methods used in the clinic include vascularized fibular grafting, vascularized iliac bone grafting, and bone grafting with preservation of muscle blood supply. These are suitable for young or middle-aged ONFH patients (ARCO Stages IIC, IIIA, and IIIB). When these surgical procedures are used appropriately, the mid- and long-term effects are good. However, the more severe surgical trauma, technical difficulty, and a certain percentage of complications at the donor site are disadvantages of these procedures. Currently, bone grafting with core decompression via the greater trochanter of the femur or via a femoral neck window is popular. Methods include support bone grafting and impaction bone grafting. Materials used for the bone graft include autologous bone, artificial substitutes, and allograft bone. These are suitable for young or middle-aged ONFH patients in ARCO Stages IIB and IIC with a necrotic volume >25%. Less surgical trauma, technical difficulty, and a small percentage of complications at the donor site are advantages of these procedures. The mid-term result is acceptable but the long-term results are still difficult to predict. The principle of osteotomy is to alter the weight-bearing surface of the femoral head, that is to say, shift the necrotic region out of the weight-bearing surface and make the non-necrotic region the weight-bearing surface. Methods include intertrochanteric varus/valgus osteotomy and transtrochanteric osteotomy. These are suitable for young or middle-aged ONFH patients with moderate Stage II and earlier stages, and middle stage III. When these surgical procedures are used appropriately the results are acceptable, but this surgery can create some technical difficulties for any future arthroplasty. This is still controversial. Some studies suggest that active treatment should be undertaken for large volume necrosis (>30%) and when the necrotic region is located on the weight-bearing surface of the femoral head, rather than waiting for symptoms to occur. Once collapse of the femoral head has progressed to the advanced stages of III, IV or V or there is joint dysfunction and severe pain, total hip replacement should be recommended. Surface replacement, metal-on-metal surface replacement, or the double-acting type of femoral head replacement should be suggested for young patients (<50 years old). These procedures are transitional surgery which preserves more bone quantity for future arthroplasty revision. The procedures above have their own variety of indications, technical requirements and corresponding complications and should be carefully chosen. Total hip arthroplasty for advanced ONFH has positive results. It is generally considered that the long-term efficacy of cementless or mixed-type prosthesis is superior to that of cement prosthesis. The surgical skills required, efficacy and complications of arthroplasty for ONFH vary according to the presence of other disorders. The surgeon should note that: For patients with a long-term history of taking steroids for an underlying disease or some other reason, postoperative infection rates may be increased. For some patients with secondary osteoporosis who have not been weight-bearing for a long time, care should be taken to avoid penetrating the acetabulum during hip replacement surgery. For some patients with failure of a previous preservation procedure, it can be difficult to insert a femoral prosthesis. An arthrodesis procedure can be suitable for younger patients with advanced unilateral ONFH who engage in a lot of physical work. Stage 0: patients with non-traumatic unilateral ONFH who have a definite diagnosis and in whom it is strongly suspected that the opposite hip may also be affected should be closely observed. Assessment by MRI is suggested at 6 monthly intervals. Stages I and II: those asymptomatic patients whose necrotic area is located in a non-weight-bearing region and whose necrotic lesion area <15%, should be closely observed and followed up regularly. Some patients who are symptomatic, or whose necrotic lesion area >15%, should be actively treated. Stages III A and B: a variety of surgical options, including bone grafting, osteotomy, and limited surface replacement, may be selected. Some patients with mild symptoms may be treated conservatively. Stages III C and IV: some younger patients with mild symptoms can be treated by joint-preservation surgery. Other options include surface replacement, total hip replacement and hip arthrodesis. Evaluation of the efficacy of ONFH treatment includes clinical results and radiographic evaluation. Hip function scores (such as the Harris score, the revised Merle d'Auligne score and SF36 evaluation) should be used for evaluation of clinical results. In evaluating imaging results, X-ray films with a template of concentric circles should be used to observe the femoral head shape, joint gap and acetabular changes. For lesions of Stages 0, I, II, MR scanning should be performed. For each patient, the clinical and radiological results are not the same, and should be assessed separately. The Chinese version of this guideline has been published in the Chinese Journal of Orthopaedics, Issue 2, Volume 27, pages 146–148.

Purpose: The appropriate surgical procedure for Stage 3 osteonecrosis of the femoral head (ONFH) remains controversial. This study aimed to evaluate and compare postoperative quality of life (QOL) in patients who underwent total hip arthroplasty (THA) and bipolar hemiarthroplasty (BHA) for ONFH based on comprehensive and disease-specific scales using patient-directed questionnaires. Methods: We included 54 of 66 patients who underwent artificial joint replacement for ONFH more than 1 year ago at our hospital between April 2013 and September 2020. THA was performed for ONFH Stage 4 and BHA for Stage 3 or below. The mean postoperative observation period in the THA and BHA groups was 3.9 and 3.7 years, respectively. The Short-Form 6-Dimension measure was used to calculate utility values. Results: No significant differences in questionnaire results regarding disease-specific or comprehensive measures were observed after arthroplasty for ONFH between the THA and BHA groups. The utility values were 0.60 and 0.58 in the THA and BHA groups, respectively. Conclusion: The postoperative QOL was similar between patients who underwent THA for Stage 4 ONFH and BHA for Stage 3 ONFH. Therefore, THA or BHA can be performed on patients with ONFH after considering age, stage classification, and previous medical conditions.

To identify modifiable factors related to post-operative dislocation and reoperation in patients with osteonecrosis of the femoral head (ONFH) in a large cohort. We studied 4995 hip arthroplasties: total hip arthroplasty (THA) was performed in 79% of patients; bipolar hemiarthroplasty (BP), 17%; total resurfacing arthroplasty (tRS), 3%; and hemi-resurfacing arthroplasty (hRS), 1%. A new type of BP (accounting for 49% of BPs) comprised a femoral component with a polished or smooth, small-diameter (approximately 10mm) neck with a round or oval axial cut surface and no sharp corners. The infection rate was relatively low (0.56%) even though 58% of cases of ONFH were associated with systemic steroid use, a known risk factor for infection. Post-operative dislocation occurred in 4.3% of cases, with re-operation needed in 3.9%. The dislocation rate was related to surgery type: 5.2% in THA, 0.9% in BP, and 0% in tRS and hRS. Among total arthroplasties with six month or longer follow-up (3670 THAs and 159 tRSs), the risk factors for post-operative dislocation were younger (≤ 40years) or older (≥ 62years) age, higher body weight, posterolateral approach, and smaller prosthetic head diameter. Regarding the need for re-operation, higher body weight and surgery type were identified as risk factors. The relatively high dislocation rate of 5.2% in THA is a cause for concern. The identified risk factors for dislocation should be considered when selecting THA for treatment. Prosthesis survivorship in hRSs was inferior to that in BPs or THAs. Body weight also affected the survivorship of hip arthroplasties.

Background:Studies have reported that patients with human immunodeficiency virus (HIV) have a high incidence of osteonecrosis of the femoral head (ONFH). Total hip arthroplasty (THA) is an effective management of ONFH. However, little data exist regarding the use of THA for the HIV patients with ONFH in China. This study reviewed the outcomes of HIV-positive patients who underwent THA for ONFH, compared with HIV-negative individuals.Methods:The patients who underwent THA for ONFH from September 2012 to September 2014 in Beijing Ditan Hospital, Capital Medical University were retrospectively studied. Twenty-eight HIV-positive patients and 35 HIV-negative patients underwent 48 THAs and 45 THAs with cementless components, respectively. Medical records and follow-up data were reviewed. Harris Hip Score (HHS) was applied to evaluate the pain and function of the hips before and after THA. Complications such as wound healing, surgical site infection, deep venous thrombosis, pulmonary embolism, sepsis, mortality, and complications from the prosthesis were reviewed. The operation time, blood loss, and hospital stay were compared between the two groups.Results:The mean follow-up period was 19.5 ± 5.8 months (ranging from 6 to 30 months). The mean age of the HIV-positive patients with osteonecrosis at the time of surgery was 35 years old, which was significantly lower than that of the HIV-negative group (42 years old) (P < 0.05). The HIV-positive patients underwent surgery a mean of 2.5 years after their original symptoms, which was significantly shorter than the HIV-negatives’ (mean 4 years) (P < 0.05). Among HIV-positive patients, the prevalence of being male and rate of bilateral procedures were significantly higher than those in the HIV-negative group (P < 0.05). The operation time in HIV-positive patients was significantly longer than that in HIV-negative patients (P < 0.05). There were no significant differences in blood loss or hospital stay between the two groups (P > 0.05). The HHSs of two groups significantly improved after THAs (P < 0.05), without significant difference between two groups. No wound complication, sepsis, mortality, prosthesis complication, and occupational exposure occurred, except for two cases of heterotopic ossification and one case of humeral head necrosis.Conclusions:ONFH is more likely to occur bilaterally in younger HIV-positive males. The development of osteonecrosis seems faster in HIV-positive patients than in HIV-negative patients. This should be cautionary for asymptomatic HIV-positive patients with low viral RNA level and in the primary HIV stage. Despite longer operation times in the HIV-positive patients than in the HIV-negative patients, THA is still a safe and efficient approach to treat ONFH in HIV-positive patients. The incidence of complications is much lower than previously reported. However, the long-term follow-up is needed.

Epidemiology, Management, and Systematic Review of Surgical Trends for Patients Who Have Osteonecrosis of the Femoral Head.

It is controversial whether bipolar hemiarthroplasty or total hip arthroplasty should be done for Ficat Stage III osteonecrosis of the femoral head. A prospective comparative study was done using the same cementless femoral components for both procedures. Forty cementless bipolar hemiarthroplasties and 31 cementless total hip arthroplasties were done in 54 patients with Ficat Stage III osteonecrosis of the femoral head. Age, gender, and followup were matched between patients having bipolar hemiarthroplasty and total hip arthroplasty. Treatment with total hip arthroplasty increased the total hip score more than treatment with bipolar hemiarthroplasty. The final pain score especially showed a significant difference between patients who had a bipolar hemiarthroplasty (5.5) and patients who had a total hip arthroplasty (5.9). Thigh pain occurred in four patients (four hips) from the bipolar hemiarthroplasty group and in six patients (six hips) from the total hip arthroplasty group. In the bipolar hemiarthroplasty group, gluteal pain occurred in six patients (six hips, 15%) and groin pain occurred in eight patients (eight hips, 20%). Dislocation occurred in two hips (two patients) in each group. The outer head migrated superiorly in nine hips (nine patients) (23%) from the bipolar hemiarthroplasty group. Because of the incidence of gluteal and groin pain and migration, total hip arthroplasty is a better procedure than bipolar hemiarthroplasty for patients with Ficat Stage III osteonecrosis of the femoral head.

BACKGROUND: Nowadays total hip arthroplasty (THA) is the method of choice for the treatment of late stages osteonecrosis of the femoral head (OFH) and osteoarthritis (OA) of the hip joint. OBJECTIVE: To evaluate the efficacy and complication pattern of THA in late stages of OFH and OA. MATERIALS AND METHODS: The study included 74 patients who underwent primary THA for OA stages IIIIV (Kellgren and Lawrence classification) and for OFH stages IIIIV (ARCO classification). Group 1 included 34 patients with OFH stages IIIIV, and group 2 40 patients with OA stages IIIIV. The groups were comparable by gender and age. All patients underwent implantation of endoprosthesis components using press-fit fixation with a metalpolyethylene articulation. Treatment results were assessed with regard to the incidence of complications and functional results at 3, 6 months, 1 and 3 years after THA. RESULTS: In our study, the survival rate of components after THA within 3 years after implantation was 100%. No cases of periprosthetic fracture, periprosthetic infection, and aseptic instability of endoprosthesis components were observed in both groups. The surface inflammation of the postoperative wound was detected in 1 (2.9%) patient in the OFH group and in 1 (2.5%) patient in OA group. Dislocation of the endoprosthesis occurred in 1 patient with OFH; there were no such findings in the OA group. The frequency of peri-implant osteolysis was twice lower (2.5%) in patients with OA compared to OFH group (5.8%). There were no statistically significant differences in the functional results dynamics before and after surgery between the groups (Harris score). The average Harris scale score in patients with OFH was 63 and reached 94 after 3 years; in OA group 58 and 94, respectively. CONCLUSION: THA is an alternative method in the treatment of severe hip arthroplasty. Endoprosthetics using a cementless endoprosthesis with a metalpolyethylene articulation demonstrated high efficacy as well as a low number of complications among patients with OFH and OA. We found no significant difference in THA results in terms of survival, postoperative complications, and functional outcome in patients with OFH and OA. Longer postoperative follow-up is advisable, which may allow us to establish some differences in treatment outcomes.

Total hip arthroplasty (THA) is a definitive option for end-stage osteonecrosis of the femoral head (ONFH). Historically, higher revision rates were observed in this population compared to THA for osteoarthritis (OA). This study provides a comprehensive evaluation of postoperative medical and surgical complications comparing THA in ONFH and OA at 90 days, 1 year, and 2 years after surgery. The PearlDiver database identified 45,002 OA and 8,429 ONFH patients who underwent THA. Mechanical complications (prosthetic loosening and osteolysis, implant failure), dislocation, renal and respiratory complications were significantly increased in the ONFH group within 2 years after THA. Pulmonary embolism rates where increased in younger ONFH patients within 2 years after THA. This data helps clinicians in the postoperative risk assessment of patients with ONFH.

Editorial Comment

Bipolar hemiarthroplasty (BHA) for idiopathic osteonecrosis of the femoral head (ONFH) is performed at our institution. The purpose of this study was to evaluate the clinical and radiographic findings after BHA for the treatment of steroid -induced ONFH. Thirty-seven hips in 27 patients were assessed (seven men, 11 hips; 20 women, 26 hips), average patient age at the time of surgery of 42.6 (range 20-83) years, with steroid-induced ONFH treated with BHA between 1995 and 2005. The mean follow-up duration was approximately ten (range five to 15) years. Patients were evaluated according to the Japan Orthopaedic Association (JOA) hip score. Kaplan-Meier survivorship was calculated to examine revision arthroplasty failure rate. Radiographic analysis of loosening included radiolucent lines and osteolysis of the acetabulum or femur. Causes of loosening were analysed using multiple logistic regression. JOA hip score increased from 53 points (preoperative) to 87 points (final follow-up). Survival rates were 96.8 % and 78.6 % at ten and 15 years, respectively. Prosthesis loosening occurred on the acetabular side in five hips (13.5 %). No femoral-component loosening was observed. BHA had poor results in patients with Association Research Circulation Osseous (ARCO) stage IV ONFH and in patients under 40 years of age. BHA, with strict surgical indications, may be a good option for treating ONFH. Based on these results, total hip arthroplasty is recommended for patients with ARCO stage IV ONFH or for patients under 40 years of age.

Osteonecrosis of the femoral head (ONFH) typically affects relatively young, active patients and frequently follows an unrelenting course resulting in considerable loss of function. In human immunodeficiency virus-infected patients, ONFH is a growing problem. Etiology, pathogenesis, and treatment of ONFH in these patients remain controversial. We analyzed retrospectively patients with ONFH in a series of 815 patients followed in our AIDS reference center. Six patients out of the 815 were affected by ONFH (0.74%). The sex ratio was 1. Two of the six patients (33.3%) had no evidence of risk factor, whereas four patients (66.6%) had risk factors. One patient had three cumulated risk factors which were corticosteroids, chemotherapy, and radiotherapy. For this patient, the onset time for ONFH was shorter (36 months). It is difficult to attribute the effect to any single class of antiretroviral agents because combination therapy is standard of care, and a change in therapies is common. All classes of antiretroviral drugs have been used: protease inhibitors (mean use duration of 15.2 months before the ONFH onset), non-nucleoside reverse transcriptase inhibitors (12 months), and nucleoside reverse transcriptase inhibitors (40.5 months). ONFH was bilateral in four cases (66.6%) and unilateral in two cases (33.3%). One patient had other osteonecrosis location (both shoulders). ONFH was classified on plain radiography stage IV in five patients and stage III in one patient. All patients received initial medical treatment. It consisted of painkillers and non-weight bearing of the hip. All were finally operated on by total hip arthroplasty (THA). The average interval between ONFH diagnosis and the first THA was 10.3 months for the six patients. A controlateral THA was performed for three patients after a mean interval of 23.3 months after ONFH diagnosis. Of the nine implanted prostheses, four were cemented, four were cementless, and one was resurfacing prosthesis.

Primary total hip arthroplasty (THA) procedures continue to increase. On the basis of data from 2000 to 2014, the frequency of THA in the U.S. is projected to grow to 635,000 procedures per year by 20301. The majority of implants from these procedures are expected to last >20 years. A study of 94,292 total hip replacements from the Finnish Arthroplasty Registry noted a survivorship of 58% at 25 years2. THA complications (especially periprosthetic joint infection [PJI] and dislocation), as well as perioperative management to optimize short stays and outpatient THA while minimizing perioperative complications, continue to draw heavy attention. Implant Design and Related Outcomes In a study evaluating 2016 data from the American Joint Replacement Registry (AJRR) compared with other national registries, the authors found that cementless stem fixation combined with the use of ceramic and 36-mm heads was the current preference in the U.S., while other registries indicated that cemented implants and metal and 32-mm heads were most commonly used3. Cemented Versus Cementless Implants There is evidence that cemented implants outperform cementless counterparts in elderly patients when early complication rates are compared. On the basis of the recent Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) annual report, Tanzer et al. reported that, among patients >75 years of age who underwent THA, those treated with the best-performing cementless femoral stems had more early revisions (<30 days postoperatively) compared with those treated with the best-performing cemented implants4. These early revisions were mainly attributable to the risk of revision for fracture or loosening. This difference disappeared after 90 days following surgery4. Bearing Surfaces Metal-on-Polyethylene (MoP) Studies show better long-term survival with a metal-on-highly-cross-linked-polyethylene (HXLPE) articulation compared with metal-on-conventional, non-cross-linked polyethylene (CPE) in younger patients5-7. In a retrospective review of 101 hips in 84 patients ≤50 years of age, with a duration of follow-up of 15 to 20 years, cobalt-chromium (CoCr)-on-CPE showed a high rate of wear-related revision (13 of 101, 12.9%)5. In contrast, the authors of another report noted excellent 15-year survivorship and functional outcome with no wear-related revision in a cohort of 82 patients (89 hips) ≤50 years of age with CoCr-on-HXLPE6. An observational study from the AOANJRR showed that hips in which XLPE was used (199,131 procedures) had a significantly lower revision rate at 16 years following THA for osteoarthritis compared with hips in which CPE was used (41,171 procedures), regardless of the head material7. Ceramic-on-Ceramic (CoC) or Ceramic-on-Polyethylene (CoP) Clicking or squeaking continues to be present in a small percentage of patients who undergo THA with CoC components. In 1 report, audible noise was present in 6.4% of hips (48 of 749) following THA with use of fourth-generation alumina CoC bearings, although no patient underwent revision for clicking or squeaking8. The selection of CoP recently surpassed MoP as the most popular bearing surface used in THA in the U.S.9. Metal-on-Metal (MoM) A study from Korea demonstrated an acceptable rate of aseptic loosening (cup, 10.5%; stem, 6.1%) in a cohort of 114 hips treated with THA using 28-mm MoM components; the average follow-up was 20 years (range, 17 to 23 years)10. Nonetheless, the use of an MoM articulation continues to decline secondary to persistent concerns for metal debris-induced adverse local tissue reactions. Surface Treatment The authors of a prospective multicenter study reported that, at the 5-year follow-up, titanium alloy (Ti6Al4V) acetabular shells with a porous titanium coating (PTC) had a higher percentage of gaps/radiolucency compared with plasma-sprayed (PS) acetabular shells from the same manufacturer (23% versus 5%). Patients in the PTC group had more patient-reported pain, although none underwent revision for loosening11. Short Versus Standard Stems In a randomized double-blinded study, persistent mid-thigh pain was much more prevalent among patients with a short Collum Femoris Preserving (CFP) stem (LINK) (19%) compared with a full-profile wedge-tapered Alloclassic Zweymüller stem (Zimmer) (7%) at medium-term follow-up. Both cohorts, however, had a high percentage of varus malalignment (14% and 16%, respectively), and the results may not be generalizable to other cementless designs12. The association between periprosthetic femoral fracture and length/geometry of cementless implants was also studied. In a cohort study of 5,090 consecutive, direct-anterior primary THAs performed at a single institution, the incidence of periprosthetic fracture using femoral components with 4 variations in length and geometry was evaluated13. All stems were of a single-taper wedge design from the same manufacturer, with 1 of 4 configurations: full-length, standard profile; full-length, reduced distal profile; short-length, standard profile; and short-length, reduced distal profile. There was a trend toward a higher risk of periprosthetic fracture in the short-length-with-standard-profile group13. It is unclear whether the same trend would hold using other surgical approaches. Head Size In a study using data from the Nordic Arthroplasty Register Association database and including 186,231 patients who underwent MoP THA with use of a 28, 32, or 36-mm head, the authors found that the risk of dislocation was reduced with the use of 32 versus 28-mm heads, although the overall revision risk remained similar. Surprisingly, transitioning from 32 to 36-mm heads was associated with a higher risk of revision for all causes, including the risk of dislocation14. It appeared that 32-mm heads would be the optimal choice for MoP THA. Dual-Mobility Constructs Modular dual-mobility constructs employ a CoCr articular surface liner that locks into an outer shell of titanium. A systematic review of mid-term studies of dual-mobility constructs supports their efficacy in reducing the incidence of dislocation after both primary and revision THA15. The wear rate for contemporary dual-mobility constructs using an HXLPE design showed substantially larger magnitudes of initial head penetration and wear than those reported for HXLPE in fixed-bearing couples (twice the rate)16. It approaches a steady state after 2 years, making it comparable with traditional fixed bearings; future studies should address the long-term outcomes16. A propensity score-matched study showed that patients with a dual-mobility construct had a lower risk of revision due to dislocation, although there was no difference in the overall risk of revision between the dual-mobility construct group and the MoP/CoP group. The authors speculated that selection bias may have been present, as the dual-mobility construct group also showed a higher risk of revision due to infection17. Patient Factors in Relation to Outcomes Medical Comorbidities Dialysis dependence was demonstrated to be an independent risk factor for 30-day adverse events, intensive care unit (ICU) care, longer length of stay, and rehabilitation needs in patients undergoing total joint arthroplasty (TJA)18. Patients with hepatitis C who received interferon or direct antiviral agents prior to THA appeared to have fewer postoperative complications, especially PJI19. Dorr Type In a matched comparative study, a higher incidence of femoral stem-related complications (mainly periprosthetic femoral fractures) was observed when using double-tapered wedge stems in Dorr type-A compared with type-B femora20. A study correlating proximal femoral morphology and leg length after THA showed that patients with a Dorr type-A femur and a high femoral cortical index (FCI, defined as the ratio of cortical width minus endosteal width to the cortical width at a level 100 mm below the tip of the lesser trochanter on an anteroposterior radiograph of the hip) were at increased risk of leg lengthening while patients with a Dorr type-C femur and a low FCI had an increased probability of shortening21. Body Mass Index (BMI) Several studies showed a higher risk of complications (up to 3 times) among THA patients classified as morbidly obese compared with normal controls22-24. In particular, researchers in the U.K. reported on, to our knowledge, the largest longitudinal cohort study to date analyzing the influence of BMI on THA outcomes (>410,000 patients)25. Patients who were morbidly obese (BMI of 40 to 60 kg/m2) had the highest probability of revision at 10 years (twice that of the underweight group), while 90-day mortality was significantly higher for the underweight group compared with those with normal BMI. Milder obesity (BMI of 25 to 40 kg/m2) seemed to have a protective effect against mortality25. In another study, patients classified as super obese (BMI of ≥45 kg/m2) had a greater risk of reoperation and readmission and greater 90-day costs compared with the nonobese cohort, but they had comparable quality-of-life improvements26. Patients classified as morbidly obese who underwent bariatric surgery prior to TJA showed a reduced comorbidity burden at the time of TJA, with reduced post-TJA complications; however, the risk of revision was not reduced27. While obesity seems to be a major negative predictor of adverse outcomes, some argue that THA is still cost-effective for morbidly obese and super obese groups and recommend against a cutoff threshold to avoid unnecessary loss of health-care access28. Preoperative Opioid Use Opioid use within 3 months preceding THA was an independent predictor of early revision, while obesity and anxiety/depression were also shown to predict early failure of treatment29. Significantly higher 30-day readmission and revision rates were observed among THA/TKA (total knee arthroplasty) patients with a history of long-term preoperative opioid use30. In another study, patients who used opioids preoperatively tended to have significantly lower patient-reported outcome scores and longer hospital stays, and were more likely to be discharged to a rehabilitation facility31. Tobacco Use In a recent study, smokers had a significantly higher risk of deep infection and reoperation after revision THA compared with nonsmokers, and the risk was higher than for primary THA32. The authors of a systematic review and meta-analysis found that former tobacco users had a significantly lower risk of wound complications and PJI compared with current smokers. Smoking cessation counseling prior to total joint arthroplasty is strongly advocated33. A history of smoking was also recently tied to increased risk of nerve injury in patients undergoing THA34. Surgical Approach The optimal surgical approach in primary THA remains controversial. A systematic review and meta-analysis of prospective studies showed less pain and better reported function through 90 days postoperatively for the direct anterior approach compared with the posterior approach35. However, when comparing early revision rates (<5 years from index primary surgery), the direct anterior approach was associated with a significantly higher rate of early revision due to femoral loosening compared with the posterior approach, while the posterior approach demonstrated a higher incidence of early revision due to instability36. A Dutch joint-registry study showed small improvements in the 3-month postoperative patient-reported outcome measure (PROM) for the direct anterior and posterolateral approaches compared with the direct lateral and anterolateral approaches37. Regardless of the different approaches, there are minimal differences in gait mechanics at early or late follow-up38. The long-term prognosis of lateral femoral cutaneous nerve (LFCN) neuropathy was also investigated. One study found that approximately 11% of patients had persistent LFCN neuropathic symptoms even at 6 to 8 years after direct anterior THA, and the most common presentation was numbness (37%). This, however, did not affect hip functional scores39. Complications There is substantial variation in reported THA complication rates among national databases and joint registries. The American College of Surgeons National Surgical Quality Improvement Program (NSQIP) tends to show the lowest rate of complications40. Medical Complications A study of 10-year Hospital Episode Statistics data from the U.K. including 540,623 THAs showed that postoperative medical complications decreased year-after-year despite a steady rise in the average Charlson Comorbidity Index score. The only 2 exceptions were lower respiratory tract infection and renal failure, which continued to rise41. Venous Thromboembolism (VTE) and Anticoagulation A systematic review found that industry-funded studies assessing thromboprophylaxis reported fewer patients with pulmonary embolism (PE), major bleeding, and mortality compared with nonfunded studies42. A cross-sectional study in 5 countries found that the rate of in-hospital VTE after hip arthroplasty was 0.16% in Canada, 1.41% in France, 0.84% in New Zealand, 0.66% in the U.S. (California), and 0.37% in Switzerland, while the benchmark was 0.58%. French data showed a higher rate, potentially because of the systematic use of ultrasound, which could result in the over-detection of deep venous thrombosis (DVT) but not PE43. A retrospective analysis of the NSQIP data set from 2008 to 2016 demonstrated that the risk of DVT was not associated with obesity in patients undergoing THA. The risk of PE, however, was found to be elevated in THA patients whose BMI was ≥35 kg/m2. The authors concluded that, since current pharmacologic anticoagulation regimens can reduce the DVT rate but have not been demonstrated to affect the rate of PE or death, the data do not support increased DVT anticoagulation in THA patients who are obese but without other VTE risk factors44. Dislocation Spinopelvic pathology dominated the literature on THA dislocation, with important research focused on spine-pelvis-hip radiographs in the sagittal plane and the related functional safe zone45-52. It has been proposed that the spinopelvic relationship be categorized according to 4 groups, as assessed at the preoperative evaluation (1A: normal alignment, normal mobility; 1B: normal alignment, stiff spine; 2A: flatback deformity, normal spine; 2B: flatback deformity, stiff spine). Special attention should be paid to the 2B population, for whom surgeons may consider using a dual-mobility construct with targeted 30° of anteversion relative to the functional pelvic plane (based on standing, rather than supine, anteroposterior pelvic radiography)45. A modified classification system was recently proposed on the basis of supine anteroposterior pelvic, standing anteroposterior pelvic, and sitting and standing lateral spinopelvic radiographs46. The classification system adds a hyperlordosis spinal alignment category (pelvic incidence-lumbar lordosis [PI-LL] mismatch of <–10°) and suggests a new risk assessment tool incorporating sagittal spinal alignment (coded as a number) and spine mobility/stiffness (coded as a letter) to use in revision THA. This new assessment tool was validated in a group of 222 patients who underwent revision hip replacement for recurrent instability. Results for 111 patients who were evaluated using the new spinal function assessment were compared with a matched group of 111 patients who were not evaluated using the system. The dislocation rate was 3% among patients who had the new presurgical assessment compared with 16% for those who did not46. Patients undergoing THA with a history of lumbar spinal fusion (LSF) had a >100% increased risk of dislocation compared with those who had LSF 5 years after THA53. Another study found that fusion to the sacrum as well as multiple levels of lumbar involvement dramatically increased the risk of dislocation in primary THA54. Although there was no increased perioperative spike of dislocation in patients undergoing LSF following an otherwise stable THA, 1 study demonstrated that this population had a sustained elevated risk of dislocation (0.7% per year) compared with those without LSF (0.4% risk per year)55. PJI The past decade saw tremendous effort and focus on preventing PJI in patients undergoing TJA. Current unadjusted 1-year and 5-year risks of PJI following THA were found to be 0.69% and 1.09%, respectively. After adjustment, however, there was no detectable decline in the risk of PJI over time56. Once PJI is confirmed, the 1-year weighted mortality rate was noted to be 4.22%, and 5-year mortality, 21.12%, highlighting the devastating consequence of PJI57. A PJI consortium (International Consensus on Orthopedic Infections) recently published a guideline for comprehensive hip and knee PJI diagnosis, prevention, and treatment58-65. With the new evidence-based and validated PJI criteria in 2018, PJI diagnosis now consists of a scoring system for minor criteria in both preoperative and intraoperative diagnosis66. One recent study found that there is no difference in treatment success as defined by the Delphi criteria between patients meeting minor-only criteria and those meeting a major criterion of PJI diagnosis67. Another PJI scoring model assigns relative weights to the various risk factors for PJI following TJA. A previous open surgical procedure, drug abuse, a revision procedure, and human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) were deemed the most influential factors68. A positive association between postoperative urinary tract infection and PJI after THA or TKA was established in a population-based, retrospective cohort study of 113,061 patients (≥66 years old). No association was found between acute postoperative urinary retention and PJI69. Debate continues regarding the merits of 1-stage versus 2-stage revision for PJI. In a recent Danish study, the authors reported an encouraging 91% infection-free survival rate at a minimum of 2 years of follow-up when using 1-stage cementless revision in the treatment of patients with chronic periprosthetic hip joint infection70. In another study, about 30% of revisions had an increase in the vancomycin minimum inhibitory concentration (MIC) between 2 stages, raising concerns about the potential for the emergence of resistant organisms between the stages of a 2-stage revision71. Postoperative Urinary Retention Risk factors for postoperative urinary retention have been defined, including an age of >60 years, intraoperative fluid administration of >1,350 mL, and intraoperative of an of risk factors related to postoperative urinary retention are and should be Although the percentage probability of periprosthetic femoral fracture using cementless stems was demonstrated to be only at 10 years, this dramatically increased to at years after primary another study the incidence of periprosthetic femoral fracture in stems found that the incidence of periprosthetic femoral fracture continued to increase after the decade and the incidence of aseptic loosening in the decade A study using data from the national found that the annual incidence of periprosthetic femoral fracture in primary THAs increased from of to of the of to In the report, type-C 4 more than and they were more commonly in cemented The incidence of with MoP is and an average of 5 years to metal the ratio have been shown to be higher in MoP (range, or compared with MoM (range, to Another study a level of and a ratio of to be a cutoff threshold for important MoP The levels of and to decline by and 3 months after potential in the femoral nerve was observed in 17 of patients who underwent the direct anterior approach in THA when were against the anterior of the although this was The authors of another recent study of the anterior in a relative safe to the to avoid In a recent retrospective cohort study using the A data was found to be associated with significantly lower rates of dislocation and aseptic revision of the acetabular following primary The authors when their results because of potential by In a double-blinded study in the U.K. that patients undergoing THA or the use of with an and to show a in the rate of surgical infection Current and The past decade has a rise in the incidence of both outpatient and THA, according to a recent comparative and have been for or to be while also patient supports a trend toward better postoperative outcomes when hip replacement is performed by While the majority of primary THAs are performed at surgeons are the majority of these A more relationship was by a New data set of of the was associated with a 2 to increase in the risk of complications, mortality, and revision relative to while hospital was associated with a increase in complications and a 4 to increase in The opioid has has more attention in recent years. regarding opioid after joint replacement surgery show that to of patients continue opioid use even at 1 year have been to reduce opioid without of A study indicated that fewer compared with 90 was associated with a in opioid and decreased opioid without pain scores and patient-reported In a retrospective review of patients who underwent THA and TKA reported a history of those reported and including respiratory and In this study, no patient with a who was an adverse It was also found that, for the patients with a who were or no differences could be found in the rate of Use is now an of the THA to reduce loss and the risk of by including the American Association of and Surgeons and the American of Orthopaedic Surgeons state that no of or time of administration have been shown to A recent randomized study did that multiple postoperative of reduced loss compared with a single preoperative The of 1 preoperative of 2 by 3 postoperative of of loss in Smoking A study from the demonstrated that level of 8 within 1 of TJA could significantly rates of smokers It also to of patients who reported as continued smoking and as more than after surgery among those who and A from demonstrated that the administration of could to for among patients undergoing THA, by a in postoperative pain scores of was also in reducing opioid and The of use in patients with undergoing THA or TKA was recently in a retrospective study of 2 of patients in the group and in the patients who received were not found to have a significantly higher infection rate than to the that PJI is an this study have been with the of with a a mainly a spinal using significantly the length of of patients undergoing THA by 1 Postoperative Current evidence that the postoperative of and levels following THA in patients with a normal preoperative level is the should be by risk factors and Preoperative and levels of and 4 have been as below which should consider postoperative and It has been that consider the use of the in for THA including of patients with THA with a had significantly higher than those without a and among the THA with a was greater for those The of The a of recently published studies related to the system that received a higher of In to in this 4 other with a higher of to hip replacement are to this review after the standard with a about to in an evidence-based in this treatment and risk of or after total hip a cohort study from national Danish Joint This to the knowledge, the largest study using the Danish databases to address the association between perioperative treatment and postoperative 30-day PE, and from all among patients who underwent THA. A total of patients were the study from to among received perioperative and did After use was not found to significantly increase the risk of PE, or The authors were to the of using on patients with previous and other in this of on outcomes after primary and revision total hip at the a cohort study patients who underwent primary or revision THA from through A using 32 factors found in the medical including 17 and of was used to the study population as index of of to and of With to in-hospital complications, differences were found only for wound complications and the and with patients had a significantly higher risk of mortality ratio of dislocation, wound and reoperation within 90 days and 1 year after primary THA. The authors did not a association of with aseptic periprosthetic or prior bariatric surgery outcomes following total joint arthroplasty in the morbidly A This meta-analysis studies from to 2018, with a total of patients who underwent THA or underwent bariatric surgery prior to TJA and the patients with obesity as the group. The study found that bariatric surgery prior to TJA was associated with reduced risks of medical complications, length of stay, and The risks of wound infection or and the long-term risks of dislocation, periprosthetic and revision were not the THA and TKA bariatric surgery was associated with a in the risk of PJI after but not after THA. of of and on in the after total hip the randomized The and in is a Danish study the and of 4 regimens or after THA. The was 1 surgery and 6 for for a total of 4 of the on the postoperative and patients were in the The authors found that significantly reduced compared with in the after The surgical approach versus for the study cohort was not which have the postoperative for

Osteonecrosis of the femoral head (ONFH) involves femoral head collapse, leading to hip joint pain, low back pain (LBP), and reduced quality of life. While compensatory spinopelvic alignment (SPA) changes are well-documented in hip osteoarthritis, their relationship with ONFH progression remains poorly understood. This study aimed to investigate SPA changes across different ONFH stages and evaluate the effects of total hip arthroplasty (THA) on SPA and patient-reported outcome measures (PROMs), including LBP, in patients undergoing THA at early and late stages of ONFH. This retrospective study included 82 patients with ONFH who underwent THA. Patients were classified into three groups based on ONFH stage using the Japanese Investigation Committee classification: stage 2 and 3A, stage 3B, and stage 4. Preoperative and postoperative SPA parameters (pelvic incidence, lumbar lordosis [LL], sacral slope [SS], pelvic tilt [PT], thoracic kyphosis, and sagittal vertical axis [SVA]) and PROMs (Japan Hip Disease Evaluation Questionnaire [JHEQ] and LBP Visual Analog Scale [VAS] scores) were compared across stages. SPA and PROMs were investigated preoperatively and 2years postoperatively. Preoperative SPA analysis revealed increased SS and SVA as ONFH progressed. Postoperatively, THA significantly reduced LL, SS, and SVA while increasing PT, with similar trends across all stages. Notably, stage 4 patients exhibited significantly greater increases in posterior PT. PROMs, including JHEQ and LBP VAS scores, improved significantly across all stages postoperatively, with no significant differences in the degree of improvement. THA improves compensatory SPA changes and PROMs in ONFH cases, regardless of the disease stage. However, patients with advanced-stage ONFH may experience further progression of the posterior PT postoperatively, highlighting the importance of preoperative SPA evaluation in late-stage cases.

The treatment of patients with osteonecrosis (ON) of the femoral head has changed over the last 30 years from the concept of saving the femoral head at all costs to the more recent concept of treating symptomatic femoral head collapse, in the setting of ON, with total hip arthroplasty. Approximately 20,000 patients are diagnosed in the United States with ON of the femoral head every year [1] with the average age at presentation being 38 years. Although femoral head core decompression, with or without bone grafting, for the early stages of ON is still performed with reasonable success, it plays no role in the patient with collapse. Free vascularized bone grafting of the femoral head and neck has been shown to have marginally superior results to core decompression in the treatment of pre-collapse lesions [2]; however, results are much better when used for lesions with early collapse, but subsequent THA can be less successful as a result [3]. Proximal femoral redirectional osteotomies are described in the treatment of ON of the femoral head; however, these are technically demanding surgeries with significant associated complications and can make any subsequent THA more difficult [4]. These osteotomies should be reserved for the much younger patient with modest-sized lesions [5].