Intertrochanteric Varus Osteotomy Research Articles

Effect of trochanter displacement on impingement and bone contact in total hip arthroplasty performed after curved intertrochanteric varus osteotomy for osteonecrosis of the femoral head: a simulation study

BackgroundCurved intertrochanteric varus osteotomy (CVO) is a useful treatment option for osteonecrosis of the femoral head (ONFH). However, the effect of proximal femoral deformity in cases of CVO converted to total hip arthroplasty (THA) remains unclear. The aim of this study was to evaluate the effect of trochanter displacement on impingement and the contact state of the implant and femur in THA.MethodsThirty-eight hips that had undergone CVO for ONFH were reviewed and compared with a control group of 30 contralateral hips that had not undergone surgery. The range of motion (ROM) and impingement patterns and the percentage of cortical bone in the stem placement within the femur were measured by simulation using CT-based three-dimensional template software. We also measured the ROM and the number of joints that achieved the ROM required for activities of daily living when the upward displaced apex of the greater trochanter with osteotomy was resected and compared the findings with those obtained when the apex was not resected.ResultsThe CVO group showed a significantly greater bony impingement in external rotation (68.4% vs. 43.3%, p = 0.033) and abduction (78.9% vs. 33.3%, p < 0.001) than in the control group. The CVO group showed a significantly smaller range of external rotation (19.0° [interquartile range; 4.0–28.8] vs. 38.0° [interquartile range; 36.0–41.8], p < 0.001) and abduction (23.0° [interquartile range; 8.5–38.8] vs. 56.0° [interquartile range; 50.3–60.0], p < 0.001) than in the control group. Significantly more joints achieved the ROM necessary for activities of daily living when the apex was resected than when it was not (10.5% vs. 63.2%, p < 0.001). The percentage of cortical bone in the stem placement position was significantly higher in the CVO group than in the control group in the proximal portion of the stem (25.5% vs. 0.0%, p < 0.001).ConclusionIn cases requiring conversion to THA, we recommend resecting the upward displaced apex to achieve a sufficient ROM and carefully resecting the bone to avoid malignment of the stem.

Legg-Calvé-Perthes disease following Ender nail fixation of a pediatric femoral fracture.

Introduction and importanceLegg–Calvé–Perthes disease (LCPD) sometimes occur in children, however it is difficult to diagnose it at the early stage especially in the cases there are no complaints of symptoms. Femoral shaft fractures in children cause various complications such as leg-length discrepancy, nonunion and malunion, refracture, and osteonecrosis of the femoral head. We presented a rare case in which a pediatric patient developed LCPD after femoral shaft fracture.Case presentationA healthy 8-year-old boy sustained a left femoral diaphyseal fracture following a pedestrian car accident. Fixation was achieved using retrograde Ender nails; bone union was confirmed at 3 months postoperatively, and the Ender nails were removed at 8 months postoperatively without any problems. Unfortunately, the morphological change of the ipsilateral femoral head and subtle symptoms were missed until the femoral head collapsed. LCPD was successfully treated with intertrochanteric varus osteotomy, which achieved a good clinical result.Clinical discussionAlthough the reason for the ipsilateral LCPD after the femoral shaft fracture is unclear, this case highlights the need for close postoperative follow-up of pediatric femoral fractures resulting from high-energy trauma to prevent the misdiagnosis of this coincidental complication.ConclusionThis case report describes a missed ipsilateral LCPD after a femoral diaphyseal fracture caused by high-energy trauma. Close postoperative follow-up with a detailed assessment and vigilant interpretation of postoperative radiography is imperative to avoid delayed/missed diagnosis of conditions for which early management may provide better outcomes.

Computed Tomography–Based Three-Dimensional Analyses Show Similarities in Anterosuperior Acetabular Coverage Between Acetabular Dysplasia and Borderline Dysplasia

(1) To compare the acetabular coverage between dysplasia, borderline dysplasia, and control acetabulum in a quantitative 3-dimensional manner; and (2) to evaluate correlations between the radiologic parameters and the 3-dimensional zonal-acetabular coverage. We reviewed contralateral hip computed tomography images of patients 16 to 60 years of age who underwent 1 of 3 types of surgeries: eccentric rotational acetabular osteotomy, curved intertrochanteric varus osteotomy, and total hip replacement with minimum 1-year follow-up from January 2013 to April 2018. A point-cloud model of the acetabulum created from computed tomography was divided into 6 zones. Three-dimensional acetabular coverage was measured radially at intervals of 1°. Mean radial acetabular coverage for each zone was named ZAC (zonal acetabular coverage) and was compared among the 3 subgroups (control: 25° ≤lateral center-edge angle [LCEA] <40°; borderline: 20° ≤LCEA <25°; and dysplasia: LCEA ≤20°) statistically. Further, the correlations between the ZAC in each zone and the LCEA were analyzed using Pearson's correlation coefficient. One-hundred fifteen hips were categorized as control (36 hips), borderline (32 hips), and dysplasia (47 hips). The mean anterocranial ZAC in the borderline (87.5 ± 5.7°) was smaller than that in the control (92.6 ± 5.9°, P= .005) but did not differ compared with the dysplasia (84.5 ± 7.6°, P= .131). In contrast, the anterocaudal (71.2 ± 5.0°), posterocranial (85.0 ± 6.4°), and posterocaudal (82.4 ± 4.5°) mean ZACs in the borderline were not different from those in the control (anterocaudal, 74.3 ± 4.6°, P= .090; posterocranial, 87.9 ± 4.3°, P= .082; posterocaudal, 85.1 ± 5.0°, P=.069) respectively. Although there was a very strong positive correlation with supra-anterior ZAC and LCEA (r=0.750, P < .001), the correlation between the anterocranial ZAC and LCEA was relatively weak (r= 0.574, P < .001). The anterosuperior acetabular coverage in the borderline dysplastic acetabulum is more similar to the dysplastic acetabulum than to the normal acetabulum. This study emphasizes the importance of evaluating not only the lateral but also the anterior coverage in borderline dysplasia.

Curved Intertrochanteric Varus Osteotomy vs Total Hip Arthroplasty for Osteonecrosis of the Femoral Head in Patients Under 50 Years Old

BackgroundGiven recent advances in total hip arthroplasty (THA), curved intertrochanteric varus osteotomy (CVO) is not indicated as a treatment for osteonecrosis of the femoral head (ONFH), unless indicated to maintain long-term hip function and achieve patient satisfaction. We aimed to compare the clinical outcomes of CVO with those of THA for treatment of ONFH in young adults <50 years old. MethodsThis comparative study included 105 ONFH patients: 59 patients (65 hips) who underwent CVO and 46 patients (56 hips) who underwent THA. Assessment tools included the Harris hip score (HHS), patient-reported outcomes of the Short Form-36, Oxford hip score, Japanese Orthopaedic Association Hip-Disease Evaluation Questionnaire, and University of California, Los Angeles score, together with complication and survival rates. ResultsPreoperative HHS was significantly higher in the CVO group than in the THA group (P < .01). At the last follow-up, no between-group differences were noted in HHS, all domains of Japanese Orthopaedic Association Hip-Disease Evaluation Questionnaire scores, Oxford hip score, and Short Form-36. University of California, Los Angeles scores and complication rates were comparable: 3% for the CVO and 7% for the THA group. The 10-year survival rate with surgery for any reason as the end point was comparable, at 91.8% for the CVO and 97.7% for the THA group. ConclusionFunctional outcomes, survival rate, and sporting activities for patients <50 years old undergoing CVO or THA for ONFH were comparable after a mean follow-up period of 10 years. Strict indications for CVO can help maintain hip function and patient satisfaction equivalent to that for THA, in the long term.

Proof of concept: hip joint damage occurs at the zone of femoroacetabular impingement (FAI) in an experimental FAI sheep model

In ovine hips chondrolabral damage as seen in cam-type femoroacetabular impingement (FAI) can be induced via an intertrochanteric varus osteotomy. However, it is yet to proven whether the observed cartilage damage is caused by a dynamic cam type impingement. Thus we asked, (1) whether actual cartilage damage observed after FAI induction in ovine hips occurs at the predicted, computed zone of FAI; (2) whether the extent of cartilage damage increases with ambulation time in this animal model? In this experimental, controlled, comparative study 20 sheep underwent unilateral FAI induction through an intertrochanteric varus osteotomy. Preoperatively sheep underwent computed tomography to generate three-dimensional models of the osseous pelvis and femur. The models were used to predict impingement zones before and after simulated varus osteotomy using range of motion (ROM) analysis. Sheep were sacrificed after 14-40 weeks of ambulation. At sacrifice cartilage was inspected and (1) location of actual damage and computed impingement zones were compared; (2) Cartilage damage was compared between short- and long ambulation groups. (1) The average location and the extent of peripheral and central cartilage lesions did not differ with the computed impingement zones (all P>0.05). (2) Grades of central, posterior cartilage damage were more severe in the long-compared to the short ambulation group (2.2±1.8 vs 0.4±0.5; P=0.030). In this experimental ovine FAI model the surgical induction of an osseous impingement conflict between the femur and acetabulum causes cartilage damage at the zone of simulated FAI.

Do dGEMRIC and T2 Imaging Correlate With Histologic Cartilage Degeneration in an Experimental Ovine FAI Model?

Biochemical MRI of hip cartilage such as delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) and T2 mapping is increasingly used to judge cartilage quality in the assessment of femoroacetabular impingement (FAI). The current evidence is sparse about which of these techniques yields a stronger correlation with histologic cartilage degeneration because of the difficulty in validating biochemical MRI techniques against histology in the clinical setting. Recently, an experimental ovine FAI model was established that induces chondrolabral damage and offers a validated platform to address these limitations. In a sheep model, we asked: (1) Do dGEMRIC and/or T2 values of acetabular and femoral cartilage correlate with histologic cartilage degeneration as assessed with the Mankin score? (2) Do simultaneously measured dGEMRIC and T2 values correlate in an experimental ovine FAI model? We performed an experimental pilot study on five female Swiss Alpine sheep (10 hips) that underwent postmortem MRI, including biochemical cartilage sequences, after a staged FAI correction had been performed on one side. No surgery was performed on the contralateral side, which served as a healthy control. In these sheep, an extraarticular intertrochanteric varus osteotomy was performed to rotate the naturally aspherical ovine femoral head into the acetabulum to induce cam-type FAI and chondrolabral damage comparable to human beings. After a 70-day ambulation period, femoral osteochondroplasty was performed and all sheep were euthanized after a total observation period of 210 days. Before they were euthanized, the sheep received a contrast agent and roamed and walked for at least 45 minutes. Hips were prepared to fit in a knee coil and MRI was performed at 3 T including a three-dimensional (3-D) dGEMRIC sequence, a two-dimensional (2-D) radial T2 mapping sequence, and a 2-D radial proton density-weighted sequence for morphologic cartilage assessment. Using specifically developed software, the 3-D dGEMRIC images and T2 maps were coregistered on the 2-D morphologic radial images. This enabled us to simultaneously measure dGEMRIC and T2 values using the identical regions of interest. dGEMRIC and T2 values of the acetabular and femoral cartilage were measured circumferentially using anatomic landmarks. After MRI, bone-cartilage samples were taken from the acetabulum and the femur and stained with toluidine blue for assessment of the histologic cartilage degeneration using the Mankin score, which was assessed in consensus by two observers. Spearman's rank correlation coefficient was used to (1) correlate dGEMRIC values and T2 values with the histologic Mankin score of femoroacetabular cartilage; and to (2) correlate dGEMRIC values and T2 values of femoroacetabular cartilage. A moderate to fair correlation between overall dGEMRIC values of the acetabular cartilage (R = -0.430; p = 0.003) and the femoral cartilage (R = -0.334; p = 0.003) versus the histologic Mankin score was found. A moderate correlation (R = -0.515; p = 0.010) was found among peripheral dGEMRIC values of the acetabulum, the superior femoral cartilage (R = -0.500; p = 0.034), and the histologic Mankin score, respectively. No correlation between overall and regional femoroacetabular T2 values and the histologic Mankin scores was found. No correlation between overall and regional femoroacetabular dGEMRIC values and T2 values was found. In this recently established sheep model, we found dGEMRIC values correlated well with histologic evidence of cartilage degeneration in the hip. This combination of a robust animal model and an accurate imaging technique appears to offer a noninvasive means to study the natural course of FAI and to compare the effectiveness of potential surgical options to treat it. This translational study supports the continuing use of dGEMRIC as a biomarker for prearthritic cartilage degeneration with the ultimate goal to identify patients who will benefit most from corrective FAI surgery. The value of T2 imaging of hip cartilage warrants further investigation.

Vascular supply of the femoral head in sheep-Implications for the ovine femoroacetabular impingement model.

Sheep hips have a natural non-spherical head similar to a cam-type deformity in human beings. By performing an intertrochanteric varus osteotomy, cam-type femoroacetabular impingement can be induced experimentally. In sheep, the aspherical portion is located superiorly-exactly matching the region where the superior retinacular vessels enter the femoral head-neck junction in human beings. In order to fully exploit the potential of this experimental FAI model, a safe osteochondroplasty of the superior asphericity would need to be done without the risk of avascular necrosis. The aim of this study was to describe the vascular anatomy of the femoral head in sheep from the aorta to the retinacular vessels in order to perform safe femoral osteochondroplasty of the superior femoral asphericity in sheep. Sixty-two ovine hips were analyzed using CT angiography (30 hips), post mortem intravascular latex injection (6 hips), vascular corrosion casting (6 hips), and analysis of the distribution of vascular foramina around the femoral head-neck junction in macerated ovine femora (20 hips). The ovine femoral head receives its blood supply from anterior retinacular arteries from the lateral femoral circumflex artery, and from posterior retinacular arteries from the medial femoral circumflex artery. The superior aspherical portion is free of vessels. Detailed knowledge about vascular anatomy of sheep hips is of clinical significance since it allows to perform osteochondroplasty of the superior aspherical portion in the experimental ovine FAI model safely without the risk of osteonecrosis. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2340-2348, 2018.

Surgical therapy of ischiofemoral impingement by lateralizing intertrochanteric osteotomy

Lateralizing, derotating intertrochanteric varus osteotomy to increase the ischiofemoral space to counter painful impingement of the lesser trochanter and the os ischium with resulting entrapment of quadratus femoris muscle. Symptomatic ischiofemoral impingement (IFI) caused by Coxa valga et antetorta, Coxa valga or Coxa antetorta, or ashort femoral neck. Anatomic configuration suggestive of IFI in asymptomatic patients. Symptomatic IFI caused by another underlying pathology. Valgus deformity of the knee. Measurement of femoral antetorsion. Planning of the osteotomy, lateralization, varus angle for correction, rotation and offset correction, leg length change, and osteosynthesis plate. General or spinal anesthesia in supine or lateral position. Skin incision (15 cm) beginning lateral of the greater trochanter tip, distally along the axis of the femur. Preparation onto the femur by L‑shaped dissection of the vastus lateralis from the bone. AKirschner(K-)wire is then positioned along the anterior femoral neck to designate the femoral neck antetorsion. Atriangle set on the lateral femoral cortexis is used to determine the osteotomy angle. In the thus determined angle, asecond K‑wire is shot centrally along the femoral neck axis just inferior to its cranial cortex. About 5 mm distal to the second wire, the entry for the blade is prepared using adrill. Using the blade setting instrument, the blade is introduced into the femoral neck, then slightly pulled back. The rotation is then marked on the anterior femoral cortex proximal and distal to the planned osteotomy and the osteotomy is performed. Ablade plate without displacement is impacted. The osteotomy is then reduced, the distal fragment pulled laterally onto the plate, and the screws inserted after compression of the osteotomy with atension device. Touch-toe bearing for 6weeks, then radiological assessment of osteotomy healing before an increase in weight bearing (15 kg/week). Hip flexion limited to90° for 6weeks. Elective implant removal after 12-18months. Studies of this lateralizing varus osteotomy have not been published. The 25-year results of the conventional derotating intertrochanteric varus osteotomy technique show good functional results and low complication rates, with non-union being the most common. Arthroscopic resection of the lesser trochanter has been reported as asurgical alternative in the treatment of IFI in case reports and small series. Advantages of the osteotomy are the restoration of biomechanics and preservation of iliopsoas tendon insertion.

What factors predict the failure of curved intertrochanteric varus osteotomy for the osteonecrosis of the femoral head?

The purpose of this study was to examine the 10-year survivorship and clinical outcome after curved intertrochanteric varus osteotomy (CVO) for the osteonecrosis of the femoral head (ONFH), and to determine what factors predict the failure of this procedure. We retrospectively reviewed 102 consecutive CVOs in 93 patients diagnosed with ONFH. Mean follow-up duration was 10.1years (3.0-23.2years). Factors associated with radiographic failure (secondary collapse and/or osteoarthritic change), conversion to total hip arthroplasty (THA) and low Harris Hip Score (HHS), were assessed. The Kaplan-Meier method was used to estimate survival rate. Radiographic failure occurred in 27 hips (26.5%), and 11 hips (10.8%) were converted to THA. The 10-year survival rate was 91.0% [95% confidence interval (CI) 83.4-95.2%] with conversion to THA as the endpoint and 72.4% (95% CI 62.3-80.3%) with radiographic failure as the endpoint. Mean HHS improved from 70.0 preoperatively to 88.1 at the final follow-up (p<0.001). Multivariate Cox regression analysis showed that postoperative intact ratio <33.3% [hazard ratio (HR), 11.17; 95% CI 4.14-30.14] and center-edge (CE) angle <25° (HR 4.91; 95% CI 1.92-12.55) were independent factors determining radiographic failure. In addition, the multivariate Cox regression analysis showed that postoperative intact ratio <33.3% (HR 10.65; 95% CI 2.24-50.53) and CE angle <25° (HR 7.81; 95% CI 2.17-28.07) were also factors determining conversion to THA. Worse HHSs of <80 were seen in patients with postoperative intact ratio <33.3% (p<0.001), CE angle <25° (p<0.001), and acetabular head index <75% (p=0.006). Postoperative intact ratio <33.3% and CE angle <25° were identified as independent factors determining radiographic failure and conversion to THA. Therefore, these factors must be taken into consideration when selecting patients for CVO.

Total hip arthroplasty after failed curved intertrochanteric varus osteotomy for avascular necrosis of the femoral head.

Curved intertrochanteric varus osteotomy (CVO) is one of the good surgical procedures for avascular necrosis of the femoral head (ANFH) patients. However, some patients with failed CVO are converted to total hip arthroplasty (THA) as a salvage operation. We compared the clinical and radiographic outcomes of 10 hips converted to THA after failed CVO (Group O) (mean age 43.0 years, 8 male and 2 female) with an age and gender matched control group of 20 hips that underwent primary THA for ANFH (Group C). Perioperative blood loss in Group O was significantly higher than that in Group C (535 g vs 282 g (P = 0.002)). Infection and dislocation occurred in 1 and 2 hips in Group O. There were no significant differences in both pre- and post-Harris Hip Score (HHS) between the groups. The stems in the AP radiograph were placed at 2.1° in a valgus position in Group O, whereas those in Group O were inserted at 1.0° in a varus position, a significant difference (P = 0.01). The stem alignment in the Lauenstein view in Group O was 1.2° in the extension position and in Group C was 0.4° in the flexion position, a significantly difference (P = 0.04). THA after failed CVO provides with the stem inserted in a valgus and extension position. Operative bleeding was increased. THA after failed CVO is a technically demanding arthroplasty. We believe that careful preoperative planning and preparation are necessary for this arthroplasty.

Femoral Varus Osteotomy for Hip Instability after Traumatic Fracture Dislocations of the Hip Associated with Femoral Head Fractures: A Report of Two Cases.

Fracture of the femoral head and the acetabulum with traumatic dislocation of the hip is a severe injury representing various types and unfavorable outcome. We showed a 45-year-old man with Pipkin type-IV fracture and coxa valga. An immediate closed reduction was achieved followed by open reduction and internal fixation via a posterior approach 6 days later. However, dislocation occurred three times without traumatic events after three weeks. CT demonstrated no displacement of posterior fragments or implant failure. Femoral intertrochanteric varus osteotomy was performed to gain concentric stability and successfully resolved recurrent dislocation. Another 45-year-old woman with Pipkin type-IV fracture and coxa valga also underwent closed reduction initially and then continued conservative treatment. After eight weeks, when she started gait training, progressive pain became symptomatic. Persistent hip pain at weight bearing was not improved in spite of arthroscopic synovectomy and osteochondroplasty. Two years after injury, femoral intertrochanteric varus osteotomy was indicated and her refractory pain was resolved gradually. We suggest that femoral varus osteotomy should be considered for superolateral subluxation associated fracture dislocation of the hip in Pipkin type-IV and coxa valga.

Cementless total hip arthroplasty for patients previously treated with femoral osteotomy for hip dysplasia: the incidence of periprosthetic fracture.

Femur deformities can make stem fixation difficult in total hip arthroplasty (THA). We report the clinical results of cementless THA using a press-fit stem in patients who had previously undergone femoral osteotomy for hip dysplasia. The subjects included 66 hips in 64 patients, with the mean follow-up period of 7.3years. THA was performed at a mean period of 17.1years after intertrochanteric femoral osteotomy. Valgus osteotomy was performed in 42 hips, and varus osteotomy in 24. Clinical results were evaluated by using the Merle d'Aubigne-Postel score. Implant survival was determined with revision as the end point, and any related complications were investigated. The Merle d'Aubigne-Postel score improved from 9.4 to 16.1 at the final follow-up, without any implant loosening. However, periprosthetic femoral fractures were observed in four hips (6.0%), one intra-operatively and three within three weeks after THA. Among these cases, three hips previously had varus osteotomy (12.5%) and one hip had valgus osteotomy (2.3%). Two hips were revised with full porous stems and circumferential wiring. The five and ten year cumulative survivorship rates were 97% (range, 88.8-99.3%) and 97% (88.8-99.3%), respectively. Although the use of a press-fit cementless stem yielded acceptable results in most of the patients, perioperative femoral fracture was a major complication especially in the patients previously treated with intertrochanteric varus osteotomy. Careful planning and implant selection could be emphasized for these cases.

Perthes disease

Morbus Perthes today still poses a challenge for the orthopaedic surgeon because of the unclear aetiology as well as the controversial discussion about the role and kind of multiple treatment principles. The prognosis depends upon clinical (e.g. age at onset, reduction of range of motion, gender) and radiological (extent of necrosis, containment) parameters. Of these, only the reduced range of motion and a loss of containment can be adressed therapeutically, be it in a conservative and/or operative concept. Pelvic osteotomies have the advantage of a high potential of correction without the biomechanic disadvantages which are associated with intertrochanteric varus osteotomies. Nowadays, the use of orthoses is considered to be obsolete. Non-containment is targeted mainly on the symptomatic treatment and the correction of residual deformities. Based on the outcome after the final stage there is a risk of premature osteoarthritis with the need of early total hip replacement.

Head reduction osteotomy with additional containment surgery improves sphericity and containment and reduces pain in Legg-Calvé-Perthes disease.

Severe femoral head deformities in the frontal plane such as hips with Legg-Calvé-Perthes disease (LCPD) are not contained by the acetabulum and result in hinged abduction and impingement. These rare deformities cannot be addressed by resection, which would endanger head vascularity. Femoral head reduction osteotomy allows for reshaping of the femoral head with the goal of improving head sphericity, containment, and hip function. Among hips with severe asphericity of the femoral head, does femoral head reduction osteotomy result in (1) improved head sphericity and containment; (2) pain relief and improved hip function; and (3) subsequent reoperations or complications? Over a 10-year period, we performed femoral head reduction osteotomies in 11 patients (11 hips) with severe head asphericities resulting from LCPD (10 hips) or disturbance of epiphyseal perfusion after conservative treatment of developmental dysplasia (one hip). Five of 11 hips had concomitant acetabular containment surgery including two triple osteotomies, two periacetabular osteotomies (PAOs), and one Colonna procedure. Patients were reviewed at a mean of 5 years (range, 1-10 years), and none was lost to followup. Mean patient age at the time of head reduction osteotomy was 13 years (range, 7-23 years). We obtained the sphericity index (defined as the ratio of the minor to the major axis of the ellipse drawn to best fit the femoral head articular surface on conventional anteroposterior pelvic radiographs) to assess head sphericity. Containment was assessed evaluating the proportion of patients with an intact Shenton's line, the extrusion index, and the lateral center-edge (LCE) angle. Merle d'Aubigné-Postel score and range of motion (flexion, internal/external rotation in 90° of flexion) were assessed to measure pain and function. Complications and reoperations were identified by chart review. At latest followup, femoral head sphericity (72%; range, 64%-81% preoperatively versus 85%; range, 73%-96% postoperatively; p = 0.004), extrusion index (47%; range, 25%-60% versus 20%; range, 3%-58%; p = 0.006), and LCE angle (1°; range, -10° to 16° versus 26°; range, 4°-40°; p = 0.0064) were improved compared with preoperatively. With the limited number of hips available, the proportion of an intact Shenton's line (64% versus 100%; p = 0.087) and the overall Merle d'Aubigné-Postel score (14.5; range, 12-16 versus 15.7; range, 12-18; p = 0.072) remained unchanged at latest followup. The Merle d'Aubigné-Postel pain subscore improved (3.5; range, 1-5 versus 5.0; range, 3-6; p = 0.026). Range of motion was not observed to have improved with the numbers available (p ranging from 0.513 to 0.778). In addition to hardware removal in two hips, subsequent surgery was performed in five of 11 hips to improve containment after a mean interval of 2.3 years (range, 0.2-7.5 years). Of those, two hips had triple osteotomy, one hip a combined triple and valgus intertrochanteric osteotomy, one hip an intertrochanteric varus osteotomy, and one hip a PAO with a separate valgus intertrochanteric osteotomy. No avascular necrosis of the femoral head occurred. Femoral head reduction osteotomy can improve femoral head sphericity. Improved head containment in these hips with an often dysplastic acetabulum requires additional acetabular containment surgery, ideally performed concomitantly. This can result in reduced pain and avascular necrosis seems to be rare. With the number of patients available, function did not improve. Therefore, future studies should use more precise instruments to evaluate clinical outcome and include longer followup to confirm joint preservation.

Biochemical MRI predicts hip osteoarthritis in an experimental ovine femoroacetabular impingement model.

Cam-type femoroacetabular impingement (FAI) resulting from an abnormal nonspherical femoral head shape leads to chondrolabral damage and is considered a cause of early osteoarthritis. A previously developed experimental ovine FAI model induces a cam-type impingement that results in localized chondrolabral damage, replicating the patterns found in the human hip. Biochemical MRI modalities such as T2 and T2* may allow for evaluation of the cartilage biochemistry long before cartilage loss occurs and, for that reason, may be a worthwhile avenue of inquiry. We asked: (1) Does the histological grading of degenerated cartilage correlate with T2 or T2* values in this ovine FAI model? (2) How accurately can zones of degenerated cartilage be predicted with T2 or T2* MRI in this model? A cam-type FAI was induced in eight Swiss alpine sheep by performing a closing wedge intertrochanteric varus osteotomy. After ambulation of 10 to 14 weeks, the sheep were euthanized and a 3-T MRI of the hip was performed. T2 and T2* values were measured at six locations on the acetabulum and compared with the histological damage pattern using the Mankin score. This is an established histological scoring system to quantify cartilage degeneration. Both T2 and T2* values are determined by cartilage water content and its collagen fiber network. Of those, the T2* mapping is a more modern sequence with technical advantages (eg, shorter acquisition time). Correlation of the Mankin score and the T2 and T2* values, respectively, was evaluated using the Spearman's rank correlation coefficient. We used a hierarchical cluster analysis to calculate the positive and negative predictive values of T2 and T2* to predict advanced cartilage degeneration (Mankin ≥ 3). We found a negative correlation between the Mankin score and both the T2 (p < 0.001, r = -0.79) and T2* values (p < 0.001, r = -0.90). For the T2 MRI technique, we found a positive predictive value of 100% (95% confidence interval [CI], 79%-100%) and a negative predictive value of 84% (95% CI, 67%-95%). For the T2* technique, we found a positive predictive value of 100% (95% CI, 79%-100%) and a negative predictive value of 94% (95% CI, 79%-99%). T2 and T2* MRI modalities can reliably detect early cartilage degeneration in the experimental ovine FAI model. T2 and T2* MRI modalities have the potential to allow for monitoring the natural course of osteoarthrosis noninvasively and to evaluate the results of surgical treatments targeted to joint preservation.

Effects of intertrochanteric varus osteotomy on Norberg angle and percent coverage of the femoral head in displastic dogs

This study was conducted to assess the effects of femoral varus osteotomy on joint congruency in dogs affected by early stage hip dysplasia. Preoperative planning to move the femoral head within the acetabulum was carried out. Varisation of the femoral inclination angle (fIA) was achieved by Intertrochanteric Osteotomy (ITO). Norberg angle (NA), percent coverage (PC) of the femoral head by the acetabulum and fIA was measured from preoperative, immediate postoperative and first and second recheck radiographs of seven dogs that underwent an ITO (joint n = 9). There was significant (p < 0.05) improvement of both NA and PC in all patients as indicated by a change in the mean ± standard deviation of 78.9° ± 7.5 and 36.9% ± 5.2 to 92.2° ± 6.7 and 50.6% ± 8.3, respectively. No significant difference (p < 0.05) was observed between the values of the planned femoral inclination angle (pfIA) of the femur and the effective femoral inclination angle (efIA) obtained after surgery (115.9° ± 2.5 and 111.3° ± 6.4, respectively). These findings could encourage the use of ITO in veterinary practice and indicate that intertrochanteric varus osteotomy should be re-considered for the treatment of early stage hip dysplasia in dogs with radiological signs of joint incongruency.

Experimentally induced cam impingement in the sheep hip

Sheep hips have a natural non-spherical femoral head similar to a cam-type deformity in human beings. By performing an intertrochanteric varus osteotomy, cam-type femoro-acetabular impingement (FAI) during flexion can be created. We tested the hypotheses that macroscopic lesions of the articular cartilage and an increased Mankin score (MS) can be reproduced by an experimentally induced cam-type FAI in this ovine in vivo model. Furthermore, we hypothesized that the MS increases with longer ambulatory periods. Sixteen sheep underwent unilateral intertrochanteric varus osteotomy of the hip with the non-operated hip as a control. Four sheep were sacrificed after 14, 22, 30, and 38-weeks postoperatively. We evaluated macroscopic chondrolabral alterations, and recorded the MS, based on histochemical staining, for each ambulatory period. A significantly higher prevalence of macroscopic chondrolabral lesions was found in the impingement zone of the operated hips. The MS was significantly higher in the acetabular/femoral cartilage of the operated hips. Furthermore, these scores increased as the length of the ambulatory period increased. Cam-type FAI can be induced in an ovine in vivo model. Localized chondrolabral degeneration of the hip, similar to that seen in humans (Tannast et al., Clin Orthop Relat Res 2008; 466: 273-280; Beck et al., J Bone Joint Surg Br 2005; 87: 1012-1018), can be reproduced. This experimental sheep model can be used to study cam-type FAI.

Long-Term Results of Intertrochanteric Varus Osteotomy for the Dysplastic Hip

Total hip arthroplasty (THA) is a well established treatment for arthrosis of the hip, however many problems remain which have not yet been resolved, including component loosening and infection. Therefore, surgeons hesitate to perform THA in younger patients showing early signs of the disease. Intertrochanteric varus osteotomy was developed for osteoarthrosis with coxa valga. This procedure has been commonly used in patients with dysplastic hips. However, femoral head coverage is not sufficiently improved by this procedure. In order to overcome the disadvantages of this procedure, since 1972 we performed intertrochanteric varus osteotomy simultaneously combined with acetabuloplasty for the treatment of osteoarthrosis secondary to dysplasia. Between 1969 and 1994, we performed 104 intertrochanteric varus osteotomies for prearthrosis and early stage arthrosis of the hip due to acetabular dysplasia in 84 patients. In this study, we reviewed these patients clinically and radiographically, over 15 years. The intertrochanteric varus osteotomy alone was employed in 38 hips (varus group). Combined intertrochanteric varus osteotomy and acetabuloplasty was employed in 63 hips (combined group). The average Harris hip score at the latest follow-up in the combined group significantly higher than that in the 'varus' group. Postoperative centre-edge angle and age at operation were correlated with the Harris hip score at the most recent follow-up. The results of the present study indicate that this combined intertrochanteric varus osteotomy and acetabuloplasty for dysplastic hip should be considered in young patients when the disease is at an early stage.

Varus Derotation Osteotomy for the Treatment of Hip Subluxation and Dislocation in GMFCS Level III to V Patients With Unilateral Hip Involvement. Follow-up at Skeletal Maturity

Hip displacement is common in children with cerebral palsy (CP). The risk of hip displacement is related to gross motor function level as graded with the Gross Motor Function Classification System (GMFCS). Most clinicians agree that surgical treatment is indicated for progressive hip subluxation in patients with CP. However, it is unclear whether unilateral bony surgery and musculotenduous release is effective in cases in which the contralateral hip is well seated. The purpose of this study is to describe the fate of the original and the contralateral hip of severely involved patients with CP, GMFCS III to V, with unilateral hip subluxation or dislocation treated by unilateral femoral osteotomy with or without pelvic osteotomy along with unilateral or bilateral soft tissue release when the contralateral hip was well seated followed to skeletal maturity. A continuous group of GMFCS III to V CP patients with unilateral hip subluxation or dislocation who underwent soft tissue release (adductor and iliopsoas) and unilateral intertrochanteric varus, rotation and shortening osteotomy with or without pelvic osteotomy are included. All patients were clinically and radiologically followed from the time of presentation until skeletal maturity. Twenty-seven children and adolescents with GMFCS level III, IV, and V met the inclusion criteria. Two patients (7.4%) were GMFCS III, 5 (18.5%) were GMFCS IV and 20 (74.1%) GMFCS V. The male:female ratio was almost 1 (13 boys and 14 girls). At the time of chart and radiograph review, the average age of this patient group was 20.4 years (range: 14 to 25 y). Twelve patients (44%) required subsequent bony surgical management of the contralateral hip for subluxation or dislocation after the index procedure. Initially, in all cases there was pelvic obliquity with the operative side higher, which reversed in cases in which the contralateral hip deteriorated, and did not reverse when the contralateral hip remained stable. Nine of them were treated with femoral varus osteotomy alone and 3 underwent a combination of femoral and pelvic osteotomy. Three of these 12 (25%) patients had revision of the first hip and bony correction of the contralateral hip. Age at surgery did not seem to have a significant effect on maintaining reduction or in preventing the contralateral hip to deteriorate. The rates of recurrence of the original hip and contralateral hip subluxation and dislocation after unilateral bony surgery in GMFCS III to V spastic patients are higher than those of other earlier series. However, in this series patients were followed until skeletal maturity. It is prudent to warn families of the possibility of long-term subluxation or dislocation of the original hip and development of the hip dysplasia requiring surgery on the contralateral side. Consideration should be given to adductor and iliopsoas release and bony surgery on the contralateral side in a GMFCS level III to V child undergoing surgery for hip displacement, even when the hip seem radiologically normal. If unilateral bony surgery is carried out, close radiological follow-up of both hips is recommended. It also seems that unilateral hip surgery alters the forces maintaining pelvic alignment, which can lead to destabilization of the contralateral hip. Case series. Level IV.

Long-term results of intertrochanteric varus osteotomy for dysplastic osteoarthritis of the hip

The beneficial role of intertrochanteric varus or valgus osteotomy in the treatment of hip osteoarthrosis has been recognised since the 1920s. Even today, it has an important role to delay the need for hip replacement in younger patients. The purpose of this study was to evaluate the long-term results of intertrochanteric varus osteotomy for dysplastic osteoarthritis of the hip. Between 1980 and 1995, 52 hips with dysplastic osteoarthritis underwent an intertrochanteric varus osteotomy. All patients could be followed up after 17.8years. Radiographic assessment included centre-edge (CE) angle of Wiberg and collodiaphyseal (CCD) angle. Dysplastic hip dislocation was classified according to Crowe. Osteoarthritis was graded according to Tönnis. Preoperative osteoarthritis was Tonnis grade 1 in 19 hips, grade 2 in 28 and grade 3 in five. Complications were also documented. Clinical evaluation included score according to Merle d'Aubigné, Harris Hip Score and range of motion. Six of 52 patients underwent total hip replacement (THR) within fiveyears after intertrochanteric osteotomy. In these cases, preoperative osteoarthritis was grade 3 in four cases and grade 2 in one case according to Tönnis. Twenty-five of 52 patients underwent THR after an interval of five to ten years after intertrochanteric osteotomy. In these cases, preoperative osteoarthritis was grade 3 in one case and grade 2 in 24 cases according to Tönnis. Sixteen of 52 patients underwent THR after an interval of ten to 15years after intertrochanteric osteotomy. In these cases, preoperative osteoarthritis was grade 2 in four cases and grade 1 in 12 cases according to Tönnis. In five patients the hip was functioning well after a period longer than 15years. In all these cases osteoarthritis was grade 1 according to Tönnis. In 40.4% of patients, THR was delayed longer than tenyears. The osteotomy performed well at a mean time of 9.7years after the procedure (range 3-21). Intertrochanteric varus osteotomy for dysplastic osteoarthritis of the hip should be considered in early or mild osteoarthritic changes of the hip. Good prognosis with delay of THR of more than tenyears can be expected to exceed 40%, even when indications are less than optimum.