Total Hip Arthroplasty in Patients With Osteopetrosis

BackgroundOsteopetrosis is an inherited bone disease associated with high risk of osteoarthritis and fracture non-union, which can lead to total hip arthroplasty (THA). Bone quality and morphology are altered in these patients, and there are limited data on results of THA in these patients. The goals of this study were to describe implant survivorship, clinical outcomes, radiographic results, and complications in patients with osteopetrosis undergoing primary THA.MethodsWe identified 7 patients (9 hips) with osteopetrosis who underwent primary THA between 1970 and 2017 utilizing our total joint registry. The mean age at index THA was 48 years and included two males and five females. The mean follow-up was 8 years.ResultsThe 10-year survivorship free from any revision or implant removal was 89%, with 1 revision and 1 resection arthroplasty secondary to periprosthetic femoral fractures. The 10-year survivorship free from any reoperation was 42%, with 4 additional reoperations (2 ORIFs for periprosthetic femoral fractures, 1 sciatic nerve palsy lysis of adhesions, 1 hematoma evacuation). Harris hip scores significantly increased at 5 years (P = .04). Five hips had an intraoperative acetabular fracture, and 1 had an intraoperative femur fracture. All postoperative femoral fractures occurred in patients with intramedullary diameter less than 5 mm at a level 10 cm distal to the lesser trochanter.ConclusionPrimary THA in patients with osteopetrosis is associated with good 10-year implant survivorship (89%), but a very high reoperation (58%) and periprosthetic femoral fracture rate (44%). Femoral fractures appear associated with smaller intramedullary diameters.     

No Difference in Dislocation Rates Comparing Large Diameter Jumbo Femoral Heads and Dual-Mobility Bearings in Revision Total Hip Arthroplasty

BackgroundDual-mobility (DM) bearings reduce instability in revision total hip arthroplasty (THA); however, DM bearings are costly and reports of corrosion have recently emerged. Furthermore, no study has compared DM to standard bearings with large diameter femoral heads ≥40-mm. This study’s purpose was to compare postoperative dislocation rates of standard and DM bearings with large femoral heads after revision THA.MethodsA retrospective review of 301 consecutive revision THAs was performed. The mean follow-up was 37.1 months. To isolate the effect of the double articulation, standard and DM bearings with femoral heads ≥40-mm were compared. Outcomes were postoperative dislocation and reoperation within 90 days.ResultsThe cohort consisted of 182 standard bearings and 75 DM bearings. There were no differences in revision indication comparing standard and DM bearings (P = .258). Overall dislocation rate was 8.6% (22 of 257). The dislocation rate was 5.7% for standard bearings with ≥40-mm femoral heads compared with 6.9% in DM bearings with ≥40-mm femoral heads (P = 1.000). In multivariate analysis, lower body mass index (odds ratio 1.72), female sex (odds ratio 2.01), and decreased outer femoral head diameter–to–cup component size ratio (odds ratio 1.64) were predictors of postoperative dislocation regardless of bearing type.ConclusionThis study showed no difference in dislocation rates between standard and DM bearings when comparing similar femoral head diameters of ≥40-mm used in revision THAs. Considering the cost and potential deleterious issues associated with additional interfaces, DM bearings should be used judiciously considering similar results may be achieved with single-articulation bearings using large femoral heads.Level of EvidenceLevel III.     

Contemporary Mortality Rate and Outcomes in Nonagenarians Undergoing Primary Total Hip Arthroplasty

BackgroundNonagenarians (90-99 years) have experienced the fastest percent growth in primary THA utilization recently. However, there are limited data on this population. This study aimed to determine the mortality rate, implant survivorship, clinical outcomes, and complications of primary THAs in nonagenarians.MethodsOur institutional total joint registry was used to identify 144 nonagenarians who underwent 149 primary THAs for osteoarthritis only between 1997 and 2017. The mean age was 92 years, with 63% being female. Mortality, revision, and reoperation were assessed using cumulative incidence with death as a competing risk and Cox regression methods. Clinical outcomes were assessed using Harris hip scores (HHSs). Cemented femoral components were used in 68%. The mean follow-up was 4 years.ResultsThe mortality rates were 6%, 8%, 14%, and 49% at 90 days, 1 year, 2 years, and 5 years, respectively. The 5-year cumulative incidences of any revision and reoperation were 1% and 4%, respectively. The mean HHS improved significantly from 48 preoperatively to 76 at 5 years (P < .001). The 5-year cumulative incidence of any complication was 69%, with the most common being periprosthetic femur fracture (7) intraoperatively, delirium (25) early postoperatively, and periprosthetic femur fracture (10) later postoperatively. Uncemented stem fixation was associated with a higher risk for intraoperative femur fracture (Hazard ratio 5, P = .04) but not with a higher 5-year periprosthetic postoperative femur fracture risk (P = .19).ConclusionNonagenarians undergoing primary THA had substantial mortality rates at 90 days (6%) and 1 year (8%). While the cumulative incidence of any revision and reoperations were low at 5 years, the high complication rate is mostly due to periprosthetic fractures.Level of evidenceLevel IV, retrospective cohort.     

Revision Total Hip Arthroplasty for Aseptically Failed Metal-On-Metal Hip Resurfacing Arthroplasty

BackgroundWhile common, studies assessing outcomes of failed metal-on-metal (MoM) resurfacings converted to total hip arthroplasties (THAs) are limited. We determined the outcomes following revision THA of aseptic MoM hip resurfacings.MethodsBetween 2000 and 2019, we identified 52 revision THAs for failed MoM hip resurfacings through our total joint registry. Mean age was 55 years, 42% were women, and mean body mass index was 28 kg/m². Adverse local tissue response led to THA in 67% of the cases. The most common revision articulation was metal-on-cross-linked or ceramic-on-cross-linked polyethylene (71%). Median head size was 36 mm. The acetabular component was retained in 21% and 28% used dual-mobility constructs. The mean follow-up was 6 years (range, 2-12 years).ResultsThe 5-year survivorships free of any re-revision or reoperation were 89% and 85%, respectively. The primary cause of re-revision (6) was dislocation (4). The 5-year cumulative probability of dislocation was 19% and was 13% in those patients treated with dual-mobility constructs versus 22% in those treated with standard articulations (P = .58). No dislocations occurred in THAs with retained acetabular components and dual-mobility constructs versus a 5-year cumulative probability of dislocation of 25% in those with revised acetabular components and standard articulations (P = .24).ConclusionRevision THAs for aseptically failed MoM hip resurfacings yielded a 5-year survivorship free of re-revision of 89%. The main reason for failure was dislocation, which was reduced, but not statistically significantly, when a dual-mobility construct was used, especially if the acetabular component was retained.Level of EvidenceIV.     

Total Hip Arthroplasties for Hartofilakidis Type C1 and C2 High Hip Dislocations Demonstrate Similar Survivorship and Clinical Function at Minimum 10-year Follow-up With Cementless Implants

BackgroundThis study aimed to determine the differences in survivorship, clinical function, and complications among patients who have Hartofilakidis Type C1 or C2 developmental dysplasia of the hips and underwent total hip arthroplasty (THA) with cementless implants.MethodsThis retrospective study identified 84 Hartofilakidis Type C hips that underwent THA between 2002 and 2011 with a minimum 10-year follow-up (mean, 13 years, range, 10 to 19 years). Survivorship, latest Harris Hip Scores and satisfaction levels, radiographic outcomes (eg, implant stability, rate and length of subtrochanteric shortening transverse osteotomy, leg-length discrepancy, cup position, and orientation), as well as complications (eg, dislocation, periprosthetic fracture, periprosthetic joint infection) were compared to analyze the differences between Hartofilakidis C1 and C2 hips.ResultsBetween C1 and C2 hips, no difference existed in the 15-year cumulative Kaplan-Meier survivorship, with the endpoint defined as any reoperation (93.1 versus 90.8%), aseptic loosening combined with periprosthetic joint infection (93.1 versus 96.2%), or aseptic loosening (94.8 versus 96.2%), latest Harris Hip Score (87.1 versus 86.1%), vertical (6.1 versus 6.0 mm) and horizontal (11.5 versus 10.3 mm) distance to the anatomic center of rotation, postoperative leg length discrepancy (11.2 versus 15.5 mm), dislocation (5.2 versus 11.5%), stem aseptic loosening (6.9 versus 7.7%), periprosthetic fracture (3.4 versus 7.7%), and intraoperative femoral fracture (32.8 versus 23.1%). However, Type C2 hips demonstrated more severe preoperative leg length discrepancy (66.9 versus 42.5 mm) and required a higher percentage of subtrochanteric shortening transverse osteotomies (84.6 versus 36.2%) that were longer (33.7 versus 26.47 mm) than the Type C1 hips.ConclusionWith cementless cups positioned near the anatomic acetabular center and cementless stems combined with subtrochanteric shortening transverse osteotomies, THAs for the Hartofilakidis Type C1 and C2 hips demonstrated similar survivorship, clinical function, and complications.     

Anatomic and Patient Risk Factors for Postoperative Periprosthetic Hip Fractures: A Case-Control Study

BackgroundPeriprosthetic fracture remains a major source of reoperation following total hip arthroplasty (THA). Within 90 days of surgery, fractures may occur spontaneously or with minor injury and are therefore more likely related to patient factors including anatomic variation.MethodsFrom 2008 to 2018, 16,254 primary THAs were performed at our institution; of those, 48 were revised for periprosthetic fracture within 90 days of surgery. A control group of 193 patients undergoing THA for hip osteoarthritis (OA) was randomly selected from the source population. We excluded patients with genetic bone disease and THA performed for hip fracture. We used logistic regression to analyze associations between patient factors (demographics, anatomical factors, comorbidities, surgical technique, and implants) and odds of 90-day periprosthetic fracture.ResultsIncreased age was significantly associated with fracture (P = .002), as was female gender (P = .046). After adjusting for age and gender, absence of contralateral OA was associated with increased odds of fracture relative to patients with contralateral OA (odds ratio [OR] 3.85, 95% confidence interval [CI] 1.60-9.29), as was having a contralateral THA in place (OR 3.70, 95% CI 1.59-8.60). The neck-shaft angle, femoral offset, and the Dorr classification were not associated with increased odds of fracture. Additionally, the distance from the tip of the trochanter to the top of the femoral head was associated with increased odds of fracture per half centimeter (OR 1.48, 95% CI 1.14-1.93).ConclusionRisk of early postoperative periprosthetic fracture following THA is increased with age, female gender, and increasing distance from the greater trochanter to the top of the femoral head; and decreased in the setting of contralateral hip OA. The trochanter-head distance correlation with periprosthetic hip fracture indicates that the preoperative anatomy may influence PPF, particularly regarding how that anatomy is reconstructed.     

Seasonality of Periprosthetic Femur Fractures in 12,700 Primary and Revision Total Hip Arthroplasties

Background

Periprosthetic femur fractures after primary and revision total hip arthroplasty (THA) are one of the most common long-term reasons for reoperation after THA. Previous investigations have analyzed the incidence and risk factors of these fractures. No previous study, however, has analyzed a variation in periprosthetic femur fractures between meteorologic seasons. The aim of this study was to compare the incidence of periprosthetic femur fractures after primary and revision THAs depending on the meteorologic season.

Long-Term Results of Total Hip Arthroplasty in Young Patients With Osteonecrosis After Allogeneic Bone Marrow Transplantation for Hematological Disease: A Multicenter,Propensity-Matched Cohort Study With a Mean 11-Year Follow-Up

BackgroundThe number of young patients with hematological disease requiring total hip arthroplasty (THA) is expected to increase. We aimed to investigate the long-term THA outcomes in patients with osteonecrosis of the femoral head (ONFH) following allogeneic bone marrow transplantation (BMT) for hematological disease.MethodsAll patients who underwent THA for osteonecrosis after BMT from 1997 to 2012 were identified at 2 institutions. Using propensity scores, 75 THAs in 45 patients were matched for age, gender, body mass index, American Society of Anesthesiologists score, and year of surgery with 75 THAs in 58 patients with idiopathic ONFH without a history of hematological disease (1:1 ratio). The mean age at surgery was 36.7 years and 52% were men. Clinical and radiographic evaluations were performed and clinical scores were obtained at last follow-up. Kaplan-Meier analyses were used to compare survivorship.ResultsAt a mean follow-up of 10.6 ± 3.5 years, clinical, radiographic, and survivorship outcomes, and the Harris hip scores were similar between both groups. The 13-year survivorship for all-cause revision was 93.4% for the BMT group and 95% for the control group (P = .928). No significant differences were observed between groups in the rates of reoperation (4% vs 5.3%, P = 1.000), 90-day readmission (all 5.3%), or overall mortality (4.4% vs 1.7%, P = .681). No hips had periprosthetic joint infection or septic loosening in either group. Osteolysis occurred in none of the BMT patients and in 2 hips (2.7%) of the control patients (P = .497).ConclusionThis large cohort multicenter survey at 11-year follow-up shows that contemporary cementless THA in young hematological disease patients after allogeneic BMT is not associated with a higher risk for surgical complications, revision, reoperation, readmission, and mortality compared to a matched cohort of idiopathic ONFH.     

Hip Hemiarthroplasty for Fractured Neck of Femur Revised to Total Hip Arthroplasty: Outcomes Are Influenced by Patient Age Not Articulation Options

BackgroundHip hemiarthroplasty is the most common arthroplasty option for fractured neck of femur (FNOF). Revision to total hip arthroplasty (THA) is occasionally required. This study aimed to assess the outcome of hemiarthroplasty revised to THA and to assess the impact of femoral head size, dual mobility (DM), and constrained liners.MethodsAll aseptic 1^st revisions reported to the Australian Joint Replacement Registry after hemiarthroplasty performed for FNOF when a THA was used as the revision procedure were included from September 1999 to December 2019. The primary outcome measure was the cumulative percent revision for all-causes and dislocation. The impact of prosthesis factors on revision THA was assessed: standard head THA (≤32 mm), large head THA (≥36 mm), DM, and constrained liners. Outcomes were compared using Kaplan Meyer and competing risk.ResultsThere were 96,861 hemiarthroplasties performed, with 985 revised to THA. The most common reasons for 1^st revision were loosening (49.3%), fracture (17.7%), and dislocation (11.0%). Of the hemiarthroplasty procedures revised to THA, 76 had a 2^nd revision. The most common reasons for 2^nd revision were fracture (27.6%), dislocation (26.3%), loosening (23.7%), and infection (18.4%). Femoral head size, DM, or constrained liner use did not alter the incidence of all-cause 2^nd revision. This did not change when solely looking at patients still alive. A 2^nd revision was more likely in patients aged <75 years.ConclusionThe outcome of hemiarthroplasty performed for FNOF revised to THA is influenced by patient age, not by the articulation used.     

A Comparison of Revision Rates for Dislocation and Aseptic Causes Between Dual Mobility and Large Femoral Head Bearings in Primary Total Hip Arthroplasty With Subanalysis by Acetabular Component Size: An Analysis of 106,163 Primary Total Hip Arthroplasties

BackgroundDual mobility (DM) and large femoral head bearings (≥36 mm) both decrease the risk of dislocation in total hip arthroplasty (THA). There is limited comparable data in primary THA. This study compared the revision rates for dislocation and aseptic causes between DM and large femoral heads and subanalyzed by acetabular component size.MethodsData from the Australian Orthopedic Association National Joint Replacement Registry were analyzed for patients undergoing primary THA for osteoarthritis from January 2008 (the year of first recorded DM use) to December 2019. All DM and large femoral head bearings were identified. The primary outcome measure was the cumulative percent revision (CPR) for dislocation and for all aseptic causes. The results were adjusted by age, sex, and femoral fixation. A subanalysis was performed stratifying acetabular component diameter <58 m and ≥58 mm.ResultsThere were 4942 DM and 101,221 large femoral head bearings recorded. There was no difference in the CPR for dislocation (HR = 0.69 (95% CI 0.42, 1.13), P = .138) or aseptic causes (HR = 0.91 (95% CI 0.70, 1.18), P = .457). When stratified by acetabular component size, DM reduced the CPR for dislocation in acetabular component diameter <58 mm (HR = 0.55 (95% CI 0.30, 1.00), P = .049). There was no difference for diameter ≥58 mm. There was no difference in aseptic revision when stratified by acetabular component diameter.ConclusionThere is no difference in revision rates for dislocation or aseptic causes between DM and large femoral heads in primary THA. When stratified by acetabular component size, DM reduces dislocation for acetabular component diameter <58 mm.Level of EvidenceLevel III.     

Dislocation is a Leading Cause of Decreased Survival Rate in Primary Total Hip Arthroplasty Performed by Low-Volume Surgeons: Long-Term Retrospective Cohort Study

BackgroundThis study aimed to evaluate the complications and long-term survival of primary total hip arthroplasty (THA) performed by low-volume (LV) surgeons at a LV hospital. We also determined the relationship between complications and revisions.MethodsThis retrospective cohort study included 220 THAs in 194 patients treated at our institution between 1998 and 2008, who received a minimum of a 10-year follow-up. The median annual THA volume at this hospital was 23 procedures (range, 11-32), and the annual volume per surgeon ranged from 1 to 19. We investigated the 90-day mortality and rates of periprosthetic joint infections, dislocations, and periprosthetic fractures up to the last visit (median follow-up, 11.8 years). Kaplan-Meier survival was calculated with revision as the end point.ResultsPostoperative infections, dislocations, and fractures at any time during the follow-up period were reported for 1 hip (0.5%), 23 hips (9.8%), and 4 hips (1.8%), respectively. One death occurred within the first 90 days postoperatively. Fifteen hips required revision surgery, and the survival rate was 95.5% at 5 years and 94.1% at 10 years. Of 10 hips that required early revision surgery within 5 years after the index surgery, 9 were revisions to address recurrent dislocation.ConclusionThe risk of dislocation was high. A high number of patients who underwent THA by LV surgeons required early revision because of dislocation. To achieve optimal long-term survivorship, LV surgeons should consider measures to reduce the risk of dislocation.     

Cementless Total Hip Arthroplasty for Adult Patients With Sequelae From Childhood Hip Infection: A Medium-Term Follow-Up Study

BackgroundThe aim of this study is to evaluate midterm clinical and radiographic results of total hip arthroplasties (THAs) with cementless implants for adult patients with sequelae from childhood hip infection.MethodsBetween 2002 and 2016, 165 patients (165 hips) who had a hip infection during childhood were treated with THAs with cementless implants. The average duration of follow-up was 93.5 months (range 26-206). Clinical results were evaluated via the Harris Hip Score and radiographic results were analyzed with postoperative serial X-rays.ResultsThe average Harris Hip Score increased from 27 (range 8-53) before surgery to 91 (range 45-100) at the latest follow-up examination (P < .001). At the latest follow-up evaluation, 9 cementless acetabular components demonstrated partial, nonprogressive radiolucencies. No subsidence of more than 2 mm or evidence of a radiolucent line was observed around the femoral components. Intraoperative periprosthetic fractures occurred in 11 hips, including 3 acetabular fractures, 2 fractures of greater trochanter, 1 femoral shaft fracture, and 5 fractures of femoral calcar. Postoperative complications included 3 cases of periprosthetic infection, 1 episode of dislocation, 1 case of a femoral periprosthetic fracture, 5 cases of sciatic nerve injury, 1 case of femoral nerve injury, and 1 case of squeaking from a ceramic bearing surface.ConclusionCementless THA for adult patients with sequelae from childhood hip infection presents significant technical challenges and a relatively high complication rate. With meticulous surgical planning and anticipation for the key technical challenges frequently encountered, the medium-term clinical and radiographic results of THA in this setting were good with high implant survivorship and patient satisfaction.     

Dislocation After Debridement,Antibiotics, and Implant Retention for Periprosthetic Joint Infections of the Hip

BackgroundDebridement, antibiotics, and implant retention (DAIR) is a common treatment option for hip periprosthetic joint infection (PJI). However, noninfectious outcomes of DAIR such as instability are not well reported. The purpose of this study was to evaluate risk factors for hip dislocation post-DAIR for PJI of both primary and revision total hip arthroplasty (THA).MethodsA retrospective chart review identified all patients who underwent DAIR of a primary or revision THA over a 20-year period with a minimum 1-year follow-up. A total of 151 patients met inclusion criteria, 19.9% of whom had a post-DAIR dislocation. Demographic and intraoperative variables were obtained. Patients who had modular components exchanged during DAIR to those with increased offset, increased “jump distance”, or a more stable acetabular liner were defined as patients who had “components exchanged to increase stability.” Predictors of hip dislocation post-DAIR were inserted into a multivariate linear regression.ResultsPost-DAIR dislocation rates were 16.3% in primary THAs and 25.4% in revision THAs. In patients who had “components exchanged to increase stability” during hip DAIR, there was at least an 11-fold reduction (1/odds ratio (OR), 0.09) in dislocation risk compared to patients who had no components altered during modular component exchange during hip DAIR (OR, 0.09; 95% confidence interval, 0.02-0.44; P < .001), while a 13-fold increased dislocation risk was seen in patients with a history of neuromuscular disease (OR, 13.45; 95% confidence interval, 1.73-104.09; P = .01).ConclusionsDuring DAIR of hip PJI, surgeons should consider prophylactically exchanging components to increase stability even if components appear stable intraoperatively.     

Revision Total Hip Arthroplasty in Patients With Ankylosing Spondylitis: Long-Term Results

BackgroundAnkylosing spondylitis (AS) is a common inflammatory spondyloarthropathy with hip involvement in 40% of patients. With the recent interest in the hip-spine interplay, the purpose of this study was to define the long-term outcomes of revision total hip arthroplasty (THA) in the setting of AS.Methods174 hips in patients with AS treated with revision THA from 1969 to 2016 were identified. Mean age at revision THA was 53 years and 76% were male. Cumulative incidences of any re-revision, reoperation, and dislocation were calculated using a competing risk analysis. Mean follow-up was 13 years.ResultsThe cumulative incidence of any re-revision after index revision THA was 7% at 5 years and 36% at 20 years. Cumulative incidence of any reoperation was 9% at 5 years and 38% at 20 years. Cumulative incidence of dislocation was 6% at 5 years and 8% at 20 years. Revision THAs performed with contemporary implants (2000-2016) had a lower but statistically nonsignificant cumulative incidence of any re-revision when compared with historical implants (before 2000) at 5 years (5% vs 8%), 10 years (11% vs 18%), and 15 years (11% vs 38%) (hazard ratio, 0.47; 95% confidence interval, 0.17-1.33; P = .016).ConclusionIn this large series of 174 revision THAs in patients with AS, the cumulative incidence of dislocation was 8% at 20 years. The 20-year cumulative incidence of any re-revision was 36%, which is similar to reported rates in patients with comparable demographic features without AS.Level of EvidenceLevel IV.     

Intraoperative Complications and Early Return to the Operating Room in Total Hip Arthroplasty Performed Through the Direct Anterior and Posterior Approaches. An Institutional Experience of Surgeons After Their Learning Curve

BackgroundProponents of the direct anterior approach (DAA) for total hip arthroplasty (THA) claim a faster recovery, whereas critics claim an increased risk of early femoral complications. This study analyzed intraoperative and postoperative complications requiring reoperation within one year after THA through the DAA and posterior approach (PA).MethodsA total of 2348 elective, unilateral DAA THAs in patients with osteoarthritis performed between 2016 and 2019 were matched 1:1 for age (±5 years), gender, body mass index (±5), and femoral fixation with 2348 patients who underwent PA THA during the same period. Mixed-effects logistic regression was used. Odds ratios were reported for the occurrence of intraoperative femoral fracture, postoperative femoral fracture, infection, dislocation, and other etiologies requiring reoperation within one year.ResultsIntraoperative femoral fracture occurred in 12 DAA (0.5%) and 14 PA (0.6%) patients. Twenty-five patients (1.06%) in the DAA and 28 (1.19%) in the PA group underwent reoperation within the first year. Reoperations were due to periprosthetic fracture (40%), infection (28%), dislocation (23%), and other (9%). Regression analysis revealed no difference in intraoperative femoral fracture (odds ratio (OR): 0.86, 95% confidence interval (CI): 0.40-1.86, P = .69), postoperative femoral fracture (OR: 1.10, 95% CI: 0.47-2.60, P = .83), infection (OR: 1.50, 95% CI: 0.53-5.23, P = .44), or reoperation within one year for other reasons (OR: 1.50, 95% CI: 0.25-9.00, P = .65). DAA had fewer dislocations requiring reoperation (OR: 0.20, 95% CI: 0.04-0.91, P = .02).ConclusionThis comparative study did not find differences in intraoperative or postoperative fracture or infection between DAA and PA. DAA was associated with a lower likelihood of reoperation for dislocation within one year of surgery.     

Low revision rate of dual mobility cups after arthroplasty for acute hip fractures: report of 11,857 hip fractures in the Dutch Arthroplasty Register (2007–2019)

Background and purpose — Dislocation is one of the most frequent reasons for cup revision after total hip arthroplasty (THA) for an acute fracture. A dual mobility cup (DMC) might reduce this risk. We determined the cup revision rate after THA for an acute fracture according to type of cup.Patients and methods — All THAs for an acute fracture registered in the Dutch Arthroplasty Register (LROI) during 2007–2019 were included (n = 11,857). Type of cup was divided into DMC and unipolar cup (UC). Competing risk analyses were performed with cup revision for any reason as endpoint. Multivariable Cox regression analyses with outcome cup revision were performed adjusted for sex, age, ASA class, and surgical approach, stratified for UC THA with femoral head size of 32 mm and 22–28 mm.Results — A DMC was used in 1,122 (9%) hips. The overall 5-year cup revision rate for any reason after THA for acute fracture was 1.9% (95% CI 1.6–2.2). Cup revision for dislocation within 5 years was performed in 1 of 6 DMC THAs versus 108 of 185 (58%) UC THAs. Univariable Cox regression analyses showed no statistically significant difference in cup revision rate between DMC and UC (HR = 0.8; CI 0.4–1.5). Multivariable Cox regression analyses showed lower risk of cup revision in DMC THA (n = 1,122) compared with UC THA with 22–28 mm femoral head size (n = 2,727) (HR = 0.4; CI 0.2–0.8).Interpretation — The 5-year cup cumulative incidence of revision after THA for acute fracture was comparable for DMC and UC THA. However, DMC THA had a lower risk of cup revision than UC THA with 22–28 mm femoral head.

The risk for revision in case of total hip arthroplasty (THA) after an acute fracture is higher than after hemiarthroplasty (Parker et al. 2010). Dislocation is one of the most frequent reasons for cup revision after an acute fracture (Gjertsen et al. 2007). We have shown low cup revision rates for dislocation using dual mobility cup (DMC) THA in patients with osteoarthritis (Bloemheuvel et al. 2019). The use of DMC in THA after an acute fracture might therefore be beneficial to prevent this complication. At the same time also femoral head size (in unipolar cups [UC]) and surgical approach influence the risk of revision for dislocation (Byström et al. 2003, Hailer et al. 2012, Kostensalo et al. 2013, Zijlstra et al. 2017).We hypothesized that the cup revision rate for dislocation in THA for acute fracture is lower with DMC than UC but that this can be affected by femoral head size (in UC) and surgical approach. We therefore determined the cup revision rate because of dislocation after THA for an acute fracture according to type of cup and head size.     

Exchangeable Femoral Neck (Dual-Modular) THA Prostheses Have Poorer Survivorship Than Other Designs: A Nationwide Cohort of 324,108 Patients

Background

Exchangeable neck stems, defined as those with a dual taper (that is, a modular junction between the femoral head and the femoral neck and an additional junction between the neck and the stem body), were introduced in THA to improve restoration of joint biomechanics (restoring anteversion, offset, and limb length) and reduce the risk of dislocation. However exchangeable necks have been reported to result in adverse effects such as stem fractures and acute local tissue reaction. Whether they result in a net improvement to or impairment of reconstructive survivorship remains controversial.

Questions/Purposes

(1) To compare the prosthetic survivorship and all-cause revision risk of exchangeable femoral neck THAs versus fixed neck THAs, taking known prosthetic revision risk factors into account; and (2) to compare the cause-specific revision risk of exchangeable femoral neck THAs versus fixed neck THAs, adjusting for known prosthetic risk factors.

Methods

Using French national health-insurance databases, we identified all French patients older than 40 years who underwent primary THA from 2009 through 2012. To ensure accuracy of the data, we considered only beneficiaries of the general insurance scheme (approximately 77% of the population). Characteristics of the prosthesis and the patients receiving an exchangeable femoral neck THA were compared with those receiving a fixed femoral neck THA (defined as femoral stem with only the head being exchangeable). Revision was the event of interest. Followup started on the date the THA was performed, until the patient experienced revision, died, was lost to followup, or until the followup period ended (December 31, 2014), whichever came first. Competing risk THA survivorship was calculated and compared (purpose 1), as were cause-specific Cox regression models (purpose 2). The study cohort included 324,108 individuals with a mean age of 77 years. A total of 24% underwent THA for acute trauma, and 3% of the group received an exchangeable neck THA. During the median 45-month followup (mean, 42 months; minimum, 1 day; maximum, 6 years), 11,968 individuals underwent prosthetic revision.

Results

The cumulative revision incidence was 6.5% (95% CI, 5.8%–7.3%) for exchangeable neck THAs versus 4.7% (95% CI, 4.6%–4.8%) for fixed neck THAs (p < 0.001). After controlling for potential confounding variables including age, sex, comorbidities, indication for THA, cementation, bearing surface, and the characteristics of the center where the implantation was performed, we found that the exchangeable femoral neck THA was associated with an increased hazard ratio (HR) of revision of 1.26 (95% CI, 1.14–1.38; p < 0.001) compared with the fixed neck THA. When dealing with cause-specific revision, exchangeable neck THAs had a higher incidence of revision for implant failure or periprosthetic fracture, and for mechanical complications; adjusted HRs were, respectively, 1.68 (95% CI, 1.24–2.27; p < 0.001) and 1.27 (95% CI, 1.13–1.43; p < 0.001), for exchangeable neck THAs compared with fixed ones.

Conclusions

Exchangeable neck THAs had poorer survivorship independent of other prosthetic revision risk factors. Accordingly, expected anatomic and functional benefits should be carefully assessed before choosing this design.

Level of Evidence

Level III, therapeutic study.

     

A new cemented femoral stem: a prospective study of the Stryker accolade C with 2- to 5-year follow-up

This prospective study evaluates the short-term results of a recently released cemented femoral stem design in primary cemented and hybrid total hip arthroplasty (THA). There were 100 all-cemented and 100 hybrid THAs in the 2-year study group. Good to excellent results were obtained in 96%. There was one reoperation for recurrent dislocation in each cohort (1%) and one single-staged reoperation for sepsis in the cemented cohort. There were 47 THA available for 5-year follow-up. Good to excellent results were maintained in 98%. One additional patient had a revision because of late recurrent dislocation. This study has demonstrated excellent early results and safety with this cemented femoral stem. The features include a dual-wedge geometry with a 0.88-microm Ra surface roughness, proximal macro-normalizations, distal anti-rotation grooves, and an optimized head-and-neck ratio approaching 4:1 using a standard 28-mm head.     

Deep Learning Artificial Intelligence Model for Assessment of Hip Dislocation Risk Following Primary Total Hip Arthroplasty From Postoperative Radiographs

BackgroundDislocation is a common complication following total hip arthroplasty (THA), and accounts for a high percentage of subsequent revisions. The purpose of this study is to illustrate the potential of a convolutional neural network model to assess the risk of hip dislocation based on postoperative anteroposterior pelvis radiographs.MethodsWe retrospectively evaluated radiographs for a cohort of 13,970 primary THAs with 374 dislocations over 5 years of follow-up. Overall, 1490 radiographs from dislocated and 91,094 from non-dislocated THAs were included in the analysis. A convolutional neural network object detection model (YOLO-V3) was trained to crop the images by centering on the femoral head. A ResNet18 classifier was trained to predict subsequent hip dislocation from the cropped imaging. The ResNet18 classifier was initialized with ImageNet weights and trained using FastAI (V1.0) running on PyTorch. The training was run for 15 epochs using 10-fold cross validation, data oversampling, and augmentation.ResultsThe hip dislocation classifier achieved the following mean performance (standard deviation): accuracy = 49.5 (4.1%), sensitivity = 89.0 (2.2%), specificity = 48.8 (4.2%), positive predictive value = 3.3 (0.3%), negative predictive value = 99.5 (0.1%), and area under the receiver operating characteristic curve = 76.7 (3.6%). Saliency maps demonstrated that the model placed the greatest emphasis on the femoral head and acetabular component.ConclusionExisting prediction methods fail to identify patients at high risk of dislocation following THA. Our radiographic classifier model has high sensitivity and negative predictive value, and can be combined with clinical risk factor information for rapid assessment of risk for dislocation following THA. The model further suggests radiographic locations which may be important in understanding the etiology of prosthesis dislocation. Importantly, our model is an illustration of the potential of automated imaging artificial intelligence models in orthopedics.Level of EvidenceLevel III.     

Extended Oral Antibiotic Prophylaxis After Aseptic Revision Total Hip Arthroplasty: Does It Decrease Infection Risk?

BackgroundExtended oral antibiotic prophylaxis (EOA) has been shown to reduce infection after high-risk primary total hip arthroplasties (THAs) and reimplantations. However, data are limited regarding EOA after aseptic revision THAs. This study evaluated the impact of EOA on infection-related outcomes after aseptic revision THAs.MethodsWe retrospectively identified 1,107 aseptic revision THAs performed between 2014 and 2019. Patients who received EOA >24 hours perioperatively (n = 370) were compared to those who did not (n = 737) using an inverse probability of treatment weighting model. Their mean age was 65 years (range, 19-98 years), mean body mass index was 30 kg/m² (range, 16-72), and 54% were women. Outcomes included cumulative probabilities of any infection, periprosthetic joint infection (PJI), and re-revision or reoperation for infection. Mean follow-up was 4 years (range, 2-8 years).ResultsThe cumulative probability of any infection after aseptic revision THA was 2.3% at 90 days, 2.7% at 1 year, and 3.5% at 5 years. The cumulative probability of PJI was 1.7% at 90 days, 2.1% at 1 year, and 2.8% at 5 years. There was a trend toward an increased risk of any infection (hazards ratio [HR] = 2.6; P = .058), PJI (HR = 2.6; P = .085), and re-revision (HR = 6.5; P = .077) or reoperation (HR = 2.3; P = .095) for infection in patients who did not have EOA at the final clinical follow-up.ConclusionsEOA after aseptic revision THA was not associated with a statistically significant decreased risk of any infection, PJI, or re-revision or reoperation for infection at all time points.Level of EvidenceLevel III.