Implant survival after primary total hip arthroplasty due to childhood hip disorders Results from the Danish Hip Arthroplasty Registry

What's New in Hip Replacement.

As interest in hip resurfacing arthroplasty (HRA) expands to complex pathologies, developmental dysplasia of the hip (DDH) has emerged as a challenging but increasingly considered indication. Although severe DDH often precludes resurfacing because of distorted anatomy, mild cases (Crowe I and II) may provide favorable conditions. This review evaluates outcomes of HRA in mild DDH, compares them with outcomes of total hip arthroplasty (THA) in DDH and HRA in primary osteoarthritis (OA) and assesses the potential of HRA to improve long-term function in this population. A systematic search of PubMed, Embase, and Scopus identified studies reporting outcomes of HRA in DDH. Titles and abstracts were screened, followed by full-text review. Data on demographics, outcomes, and radiographic findings were extracted. Pooled complication and survivorship rates were calculated. A random-effects meta-analysis compared revision risk in HRA-treated patients with DDH vs. OA, and in patients with DDH treated with HRA vs. THA. Statistical significance was defined as a 95% confidence interval (CI) excluding 1. A separate meta-analysis compared mean postoperative flexion in patients with DDH treated with HRA vs. THA, with significance defined as a 95% CI excluding 0. From 65 screened articles, 11 met inclusion criteria, totaling 895 patients and 1,006 hips with DDH. The mean age was 45.26 years, with an average follow-up of 7.06 years. The pooled survivorship was 93%, and the complication rate was 13%. No significant difference in revision risk was found between DDH and OA HRA cohorts, or between HRA and THA in DDH, although both trends favored OA and THA. Patients with HRA-treated DDH had significantly greater postoperative flexion (standardized mean difference -1.21, 95% CI -1.54 to -0.87). Despite anatomical challenges and a potential for higher revision or complication rates in patients with DDH, mid-term outcomes, including patient-reported outcome, were comparable with those in primary osteoarthritis and THA cohorts. This review supports the selective use of HRA in patients with Crowe I and II DDH, particularly when modern surgical techniques and DDH-specific implants are used. Level III, systematic review of Level I, III, and IV studies. See Instructions for Authors for a complete description of levels of evidence.

Background The results of primary total hip arthroplasties (THAs) after pediatric hip diseases such as developmental dysplasia of the hip (DDH), slipped capital femoral epiphysis (SCFE), or Perthes’ disease have been reported to be inferior to the results after primary osteoarthritis of the hip (OA).Materials and methods We compared the survival of primary THAs performed during the period 1995–2009 due to previous DDH, SCFE, Perthes’ disease, or primary OA, using merged individual-based data from the Danish, Norwegian, and Swedish arthroplasty registers, called the Nordic Arthroplasty Register Association (NARA). Cox multiple regression, with adjustment for age, sex, and type of fixation of the prosthesis was used to calculate the survival of the prostheses and the relative revision risks.Results 370,630 primary THAs were reported to these national registers for 1995–2009. Of these, 14,403 THAs (3.9%) were operated due to pediatric hip diseases (3.1% for Denmark, 8.8% for Norway, and 1.9% for Sweden) and 288,435 THAs (77.8%) were operated due to OA. Unadjusted 10-year Kaplan-Meier survival of THAs after pediatric hip diseases (94.7% survival) was inferior to that after OA (96.6% survival). Consequently, an increased risk of revision for hips with a previous pediatric hip disease was seen (risk ratio (RR) 1.4, 95% CI: 1.3–1.5). However, after adjustment for differences in sex and age of the patients, and in fixation of the prostheses, no difference in survival was found (93.6% after pediatric hip diseases and 93.8% after OA) (RR 1.0, CI: 1.0–1.1). Nevertheless, during the first 6 postoperative months more revisions were reported for THAs secondary to pediatric hip diseases (RR 1.2, CI: 1.0–1.5), mainly due to there being more revisions for dislocations (RR 1.8, CI: 1.4–2.3). Comparison between the different diagnosis groups showed that the overall risk of revision after DDH was higher than after OA (RR 1.1, CI: 1.0–1.2), whereas the combined group Perthes’ disease/SCFE did not have a significantly different risk of revision to that of OA (RR 0.9, CI: 0.7–1.0), but had a lower risk than after DDH (RR 0.8, CI: 0.7–1.0).Interpretation After adjustment for differences in age, sex, and type of fixation of the prosthesis, no difference in risk of revision was found for primary THAs performed due to pediatric hip diseases and those performed due to primary OA.

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

What's New in Hip Replacement.

What’s New in Hip Replacement

Use of diuretics and risk of implant failure after primary total hip arthroplasty: A nationwide population-based study

Outcomes of Ceramic Bearings After Primary Total Hip Arthroplasty in the Medicare Population

Patients actively smoking at the time of primary hip or knee arthroplasty are at increased risk of direct perioperative complications. We investigated the association between smoking status and risk of revision and mortality within 2 years following hip or knee arthroplasty. We used prospectively collected data from the Dutch Arthroplasty Register. All primary total hip arthroplasties (THAs), total knee arthroplasties (TKAs), and unicondylar knee arthroplasties (UKAs) with > 2 years' follow-up were included (THA: n = 140,336; TKA: n = 117,497; UKA: n = 14,807). We performed multivariable Cox regression analyses to calculate hazard risks for differences between smokers and non-smokers, while adjusting for confounders (aHR). The smoking group had higher risk of revision (THA: aHR 1.3, 95% confidence interval [CI] 1.1-1.4 and TKA: aHR 1.4, CI 1.3-1.6) and risk of mortality (THA: aHR 1.4, CI 1.3-1.6 and TKA: aHR 1.4, CI 1.2-1.6). Following UKA, smokers had a higher risk of mortality (aHR 1.7, CI 1.0-2.8), but no differences in risk of revision were observed. The smoking group had a higher risk of revision for infection following TKA (aHR 1.3, CI 1.0-1.6), but not following THA (aHR 1.0, CI 0.8-1.2). This study showed that the risk of revision and mortality is higher for smokers than for non-smokers in the first 2 years following THA and TKA. Smoking could contribute to complications following primary hip or knee arthroplasty.

Worldwide use of cementless fixation for total hip arthroplasty (THA) is on the rise despite some evidence from the world's registries suggesting inferior survivorship compared with cemented techniques. The patterns of bone loss associated with failed cementless and cemented THAs may prejudice the results of future revision procedures; however, this has not been documented. The purpose of this study was to compare (1) the risk for rerevision of first revision THA; (2) the patterns of femoral bone loss at the time of first revision of primary THA; (3) the reasons for first revision of primary THA; and (4) the time to first revision of primary THA between primary cementless and cemented femoral components. Primary THAs with cemented (n = 1791) and uncemented (n = 805) femoral components that subsequently sustained first revision of the femoral component were identified from the Danish Hip Arthroplasty Registry (DHR). As of 2012, 120,988 primary THAs and 19,282 revisions were registered in the DHR with completeness of 97% and 90% for primary and revision THA, respectively. Median followup for revisions of primary THA with cemented and cementless femoral component was 4 years (range, 0-17 years) and 2 years (range, 0-16 years), respectively. Survival of first revision THA, with second revision of the femur as outcome, was evaluated using hazard ratios (HRs) with 95% confidence interval (CI) adjusting for potential confounding. All patient- and surgery-related data are collected from Danish medical databases. Recording of bone defects in the DHR is based on surgeons' intraoperative findings. With the numbers studied, we found no differences in the risk of second revision between the overall cohort between cementless and cemented techniques (HR, 1.32; 95% CI, 0.97-1.80; p = 0.076); however, a second revision for any reason was more likely in patients < 70 years old in whom the index arthroplasty was performed using a cementless technique (HR, 1.48; 95% CI, 1.01-2.17; p = 0.046). Increasingly severe femoral bone defects of type II (30% [532 of 1791] versus 13% [104 of 805]; p < 0.001) type III (11% [200 of 1791] versus 2% [12 of 805]; p < 0.001) and type IV (1% [26 of 1791] versus 0.4% [three of 805]; p = 0.016) were more frequent at revisions of cemented femoral components compared with cementless femoral components. Indications for first revision differed between primary cemented and uncemented femoral components, because a larger proportion of cemented femoral components was revised as a result of aseptic loosening compared with cementless femoral components (74% [1329 of 1791] versus 25% [197 of 805]; p < 0.001), whereas a larger proportion of cementless femoral components was revised as a result of a fracture compared with cemented femoral components (46% [371 of 805] versus 10% [168 of 1791]; p < 0.001). Failure before 5 years was more likely in cementless femoral components than cemented femoral components (91% [733 of 805] versus 44% [749 of 1791], p < 0.001). We found no differences in the risk of second revision in the overall cohort between cementless and cemented techniques; however, we observed an increased risk for rerevision THA performed on patients < 70 years whose index THAs were performed using cementless components when looking at all causes for revision, even after adjusting for the most likely confounding factors. Our data suggest that increased use of cementless fixation in primary THA may lead to inferior survivorship of first revision THA. Level III, therapeutic study.

Background The effect of hydroxyapatite (HA) on implant survival in the medium and long term is uncertain. We studied the effect of HA coating of uncemented implants on the risk of cup and stem revision in primary total hip arthroplasty (THA).Patients and methods Using the Danish Hip Arthroplasty Registry (DHR), we identified patients less than 70 years old who had undergone uncemented primary THA during 1997–2005. 4,125 HA-coated and 7,737 non-HA-coated cups and 3,158 HA-coated and 4,749 non-HA-coated stems were available for analysis. The mean follow-up time was 3.4 years for cups and 3.2 years for stems. We estimated the relative risk (RR) of revision due to aseptic loosening or any cause, and adjusted for possible confounders (age, sex, fixation of opposite implant part, and diagnosis for primary THA) using multivariate Cox regression analysis.Results The adjusted RRs for revision of HA-coated cups and stems due to aseptic loosening were 0.89 (95%CI: 0.37–2.2) and 0.71 (95%CI: 0.27–1.9) with up to 9 years of follow-up, compared to non-HA-coated implants. When taking all causes of revision into consideration, the risk estimates were 0.85 (95%CI: 0.68–1.1) and 0.81 (95%CI: 0.61–1.1) for HA-coated cups and stems, respectively.Interpretation In this medium-term follow-up study, the use of HA-coated implants was not associated with any clearly reduced overall risk of revision compared to non-HA-coated implants.

The results of randomized controlled trials and systematic reviews have suggested reduced radiographic wear in highly cross-linked polyethylene compared with conventional polyethylene in primary total hip arthroplasty. However, longer-term clinical results have not been thoroughly examined, to our knowledge. The purpose of this study was to compare the risk of revision for metal-on-conventional and metal-on-highly cross-linked total hip arthroplasty bearing surfaces with use of a distributed data network of six national and regional registries (Kaiser Permanente, HealthEast, the Emilia-Romagna region in Italy, the Catalan region in Spain, Norway, and Australia). Inclusion criteria were osteoarthritis as the primary diagnosis, cementless implant fixation, and a patient age of forty-five to sixty-four years. These criteria resulted in a sample of 16,571 primary total hip arthroplasties. Multivariate meta-analysis was performed with use of linear mixed models, with survival probability as the unit of analysis. The results of a fixed-effects model suggested that there was insufficient evidence of a difference in risk of revision between bearing surfaces (hazard ratio, 1.20 [95% confidence interval, 0.80 to 1.79]; p = 0.384). Highly cross-linked polyethylene does not appear to have a reduced risk of revision in this subgroup of total hip arthroplasty patients. Arthroplasties involving highly cross-linked polyethylene do not appear to have an increased risk of revision in this subgroup of total hip arthroplasty patients.

A direct lateral approach to the hip is described which allows adequate access for orientation of the implant, for the insertion ofthe cement and for the correction ofdiscrepancy in leg length. An anatomical observation was made that the gluteus medius muscle is inserted into the greater trochanter by a tendon and that the axis of the shaft of the femur lies anterior to the main bulk of the muscle which was left

There is little data regarding timing of index dislocation in patients who undergo primary total hip arthroplasty (THA) and subsequent risk of redislocation and revision. Between 1992 and 2013, 21,490 primary THAs were performed at a single institution. 189 patients (190 hips) had a first episode of dislocation within one year of index surgery (0.9 %). 32 patients (32 hips) were excluded for the following reasons: complex THA secondary to fracture malunion, Crowe III/IV developmental hip dysplasia, periprosthetic fracture, prior hip surgery, incomplete information, and hip abductor avulsion. The final cohort consisted of 157 patients (158 hips) who experienced dislocation within 1 year of primary non-complex THA. 88 patients were female (56%), mean age was 61 years (SD = 14), and mean follow-up was 76 months (range 0-229). Multivariable Cox proportional-hazards regression models with fractional polynomial models were used to estimate the association between timing of index dislocation and subsequent redislocation and revision surgery. 69 patients (44%) redislocated at final follow-up. Revision for any cause occurred in 26 out of 157 hips (17%). Time lapse from index THA to first dislocation was significantly associated with the risk of redislocation (p = 0.004) and with the risk of revision (p = 0.04). For every additional 7 days from surgery, risk of redislocation increased by a factor of 1.1 and risk of revision was increased by a factor of 1.13. This study demonstrates there is a lower risk of redislocation and revision in patients who have a first episode of dislocation closer to primary THA.

Despite the large increase in total hip arthroplasties and total knee arthroplasties, the incidence and prevalence of additional contralateral or ipsilateral joint arthroplasty are poorly understood. The purpose of this study was to determine the rate of additional joint arthroplasty after a primary total hip arthroplasty or total knee arthroplasty. This historical cohort study identified population-based cohorts of patients who underwent primary total hip arthroplasty (n = 1,933) or total knee arthroplasty (n = 2,139) between 1969 and 2008. Patients underwent passive follow-up through their medical records beginning with the primary total hip arthroplasty or total knee arthroplasty. We assessed the likelihood of undergoing a subsequent total joint arthroplasty, including simultaneous and staged bilateral procedures. Age, sex, and calendar year were evaluated as potential predictors of subsequent arthroplasty. During a mean follow-up of 12 years after an initial total hip arthroplasty, we observed 422 contralateral total hip arthroplasties (29% at 20 years), 76 contralateral total knee arthroplasties (6% at 10 years), and 32 ipsilateral total knee arthroplasties (2% at 20 years). Younger age was a significant predictor of contralateral total hip arthroplasty (p < 0.0001), but not a predictor of the subsequent risk of total knee arthroplasty. During a mean follow-up of 11 years after an initial total knee arthroplasty, we observed 809 contralateral total knee arthroplasties (45% at 20 years), 31 contralateral total hip arthroplasties (3% at 20 years), and 29 ipsilateral total hip arthroplasties (2% at 20 years). Older age was a significant predictor of ipsilateral or contralateral total hip arthroplasty (p < 0.001). Patients undergoing total hip arthroplasty or total knee arthroplasty can be informed of a 30% to 45% chance of a surgical procedure in a contralateral cognate joint and about a 5% chance of a surgical procedure in noncognate joints within 20 years of initial arthroplasty. Increased risk of contralateral total knee arthroplasty following an initial total hip arthroplasty may be due to gait changes prior to and/or following total hip arthroplasty. The higher prevalence of bilateral total hip arthroplasty in younger patients may result from bilateral disease processes that selectively affect the young hip, such as osteonecrosis, or structural hip problems, such as acetabular dysplasia or femoroacetabular impingement. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.