Lewallen, David G.

Background: Complex acetabular reconstruction for major bone loss can require advanced methods such as the use of a cup-cage construct. The purpose of this study was to review outcomes after the initial development of the cup-cage technique and the subsequent evolution to the use of a half cup-cage construct. Methods: We performed a retrospective, single-center review of 57 patients treated with cup-cage reconstruction for major acetabular bone loss. All patients had major acetabular defects graded as Paprosky Type 2B through 3B, with 34 (60%) having an associated pelvic discontinuity. Thirty patients received a full cup-cage construct and 27, a half cup-cage construct. The mean follow-up was 5 years. Results: Both the full and half cup-cage cohorts demonstrated significantly improved Harris hip score (HHS) values, from 36 to 72 at a minimum of 2 years of follow-up (p < 0.05). Early construct migration occurred in 4 patients, with stabilization prior to 2-year follow-up in all but 1 patient. Incomplete, zone-3, nonprogressive acetabular radiolucencies were observed in 2 (7%) of the full cup-cage constructs and 6 (22%) of the half cup-cage constructs. One patient with a full cup-cage construct underwent re-revision of the acetabular component for progressive migration and aseptic loosening. Short-term survivorship free from re-revision for any cause or reoperation was 89% (83% and 96% for full and half cup-cage cohorts, respectively). Conclusions: Both full and half cup-cage constructs demonstrated successful clinical outcomes and survivorship in the treatment of major acetabular defects and pelvic discontinuity. Each method is utilized on the basis of individual intraoperative findings, including the extent and pattern of bone loss, the quality and location of host bone remaining after preparation, and the presence of pelvic discontinuity. Longer-term follow-up is required to understand the durability of these constructs in treating major acetabular defects and pelvic discontinuity. Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

AbstractSubstance P (SP), a neurotransmitter released after injury, has been linked to deregulated tissue repair and fibrosis in musculoskeletal tissues and other organs. Although SP inhibition is an effective treatment for nausea, it has not been previously considered as an anti‐fibrotic therapy. Although there are extensive medical records of individuals who have used SP antagonists, our analysis of human registry data revealed that patients receiving these antagonists and arthroplasty are exceedingly rare, thus precluding a clinical evaluation of their potential effects in the context of arthrofibrosis. Therefore, we pursued in vivo studies to assess the effect of SP inhibition early after injury on pro‐fibrotic gene expression and contractures in an animal model of post‐traumatic joint stiffening. Skeletally mature rabbits (n = 24) underwent surgically induced severe joint contracture, while injected with either fosaprepitant (a selective SP antagonist) or saline (control) early after surgery (3, 6, 12, and 24 h). Biomechanical testing revealed that differences in mean contracture angles between the groups were not statistically significant (P = 0.27), suggesting that the drug neither mitigates nor exacerbates joint contracture. However, microarray gene expression analysis revealed that mRNA levels for proteins related to cell signaling, pro‐angiogenic, pro‐inflammatory, and collagen matrix production were significantly different between control and fosaprepitant treated rabbits (P < 0.05). Hence, our study demonstrates that inhibition of SP alters expression of pro‐fibrotic genes in vivo. This finding will motivate future studies to optimize interventions that target SP to reduce the formation of post‐traumatic joint contractures.

Background: Modular fluted tapered stems have become the most commonly employed category of femoral component in revision hip arthroplasty in North America as a result of favorable early results and simplicity of use. Despite wide adoption, the majority of published data are limited to relatively small series with modest follow-up. The goal of the current study was to determine the success rate and factors associated with success, failure, and complications of the use of modular fluted tapered stems in aseptic revision total hip arthroplasties (THAs) in a large patient cohort. Methods: We identified 519 aseptic femoral revisions during which a modular fluted tapered stem was utilized. Clinical outcomes, Kaplan-Meier survivorship, radiographic outcomes, and complications were assessed. The mean age at revision arthroplasty was 70 years, the mean body mass index (BMI) was 29 kg/m 2 , and the mean duration of follow-up was 4.5 years (range, 2 to 14 years). Results: The mean Harris hip score (HHS) improved significantly from 51 points preoperatively to 76 points at 2 years (p < 0.001). This improvement was maintained at the last follow-up evaluation (mean HHS = 75 points). At the time of the most recent follow-up, 16 femoral revisions had been performed: 6 because of aseptic loosening, 4 because of infection, 3 because of instability, 2 because of periprosthetic fracture, and 1 because of stem fracture. The 10-year survivorship was 96% with revision for any reason as the end point and 90% with any reoperation as the end point. Of the patients who were alive and had not undergone revision at the time of final follow-up, 12 had stem subsidence but all but 1 of these stems had stabilized after subsiding. Postoperative complications were noted in 12% of the cases. Repeat revision due to femoral component loosening was not correlated with the preoperative bone-loss category or patient demographic factors. Conclusions: In this large series, femoral revision with a modular fluted tapered stem provided a high rate of osseointegration and sustained improvement in clinical scores at the time of the last follow-up. There was also a high rate of successful implant fixation across all categories of preoperative bone loss and an acceptable rate of complications. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Background: The use of a trabecular metal revision shell with metal augmentation to fill segmental or irregular defects during complex revision hip arthroplasty has been shown to provide good short-term results in prior published series. Longer-term results of the several cup-augment constructs used clinically are not known. The objective of this study was to report, with minimum 5-year radiographic and clinical follow-up, the outcome of these various constructs in revision total hip arthroplasty. Methods: Eighty-four patients (85 hips) underwent revision total hip arthroplasty with use of porous tantalum augments between 2000 and 2007 at a single institution and were retrospectively reviewed. Fifty-seven of the patients (58 hips) had clinical and radiographic follow-up at a minimum of 5 years. At the time of revision, the majority of the hips had acetabular defects classified as Paprosky Type 3A (28 of 58, 48%) or Type 3B (22 of 58, 38%). Eleven (19%) of the hips also had preoperative pelvic discontinuity. All hips were assessed clinically at a minimum of 5 years with use of the Mayo hip score. Postoperative radiographs were reviewed for implant stability, the presence and location of radiolucent lines and healing of the discontinuity if present. Results: In 2 (3%) of the 58 hips, the constructs failed because of aseptic loosening of the acetabular component and re-revision was indicated. Six (10%) of the 58 hips demonstrated a radiolucent line between the trabecular metal shell and bone in DeLee and Charnley zone 3. In 1 hip that underwent re-revision and in 5 of the 6 hips with a zone-3 radiolucency, a pelvic discontinuity was present at the time of the index revision. The mean preoperative Mayo hip score was 35.7, which improved to 61.9 at 3 months and was 61.7 at the minimum 5-year follow-up. Conclusions: With failure defined as aseptic loosening requiring repeat revision surgery, this cohort demonstrated 97% survivorship and maintained satisfactory hip function at the minimum 5 years after the index revision surgery. Six of the 11 hips with preoperative pelvic discontinuity either failed or developed a radiolucency in zone 3 and are considered at risk for future revision. Pelvic discontinuity should prompt consideration of the addition of adjunctive fixation or the use of alternative techniques. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Background: Pelvic discontinuity is uncommon and presents the surgeon with complex reconstructive challenges. The objective of this study is to report the results of current strategies used in the treatment of pelvic discontinuity. Methods: We retrospectively analyzed prospectively collected data on 113 consecutive revision total hip arthroplasties performed for the treatment of unilateral pelvic discontinuity at a single institution. The study included 18 male and 95 female patients with a mean age of 63 years at the time of revision surgery. Preoperative, immediate postoperative, and latest follow-up radiographs were reviewed to assess healing of the discontinuity as well as acetabular component stability. Treatment modalities included an uncemented cup with a posterior column plate (50 hips; 44%), a cup-cage construct (27 hips; 24%), an antiprotrusio cage with or without a posterior column plate (26 hips; 23%), and an uncemented cup alone (10 hips; 9%). The average duration of follow-up for each of these types of surgical reconstruction was similar (range, 3.9 to 7.2 years). Results: Five-year revision-free survivorship of the implant was best with a cup-cage construct (100%) and worst with an uncemented cup with a posterior column plate (80%) and a cup alone (80%). Healing of the discontinuity was achieved in 50% of the hips with an uncemented cup alone, 74% of the hips with an uncemented cup and a posterior column plate, 74% of the hips with a cup-cage construct, and 88% of the hips with an antiprotrusio cage construct (91% of these hips when structural allograft was used). The overall complication rate was 26.5%. The average Harris hip score improved from 54 preoperatively to 69 postoperatively (95% confidence interval: 50 to 57 preoperatively and 65 to 72 postoperatively; p = 0.017). Conclusions: Improved survivorship and healing rates were seen in this series when a reconstruction cage was used as an adjunct to an uncemented cup (cup-cage) or in combination with structural allograft bone that bridged the discontinuity. Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Background: Total knee arthroplasty (TKA) with a rotating-hinge prosthesis is considered a salvage procedure. While excellent immediate stability is achieved, the historically high failure rate has tempered its use. The goal of this study was to determine clinical outcomes, radiographic results, and survivorship after TKA with contemporary rotating-hinge components. Methods: We identified 408 consecutive TKAs performed with rotating-hinge components for nononcologic indications from 2002 to 2012 at a single academic institution. Two hundred and sixty-four knees (65%) had rotating-hinge TKA components implanted for aseptic etiologies, while 144 knees (35%) were managed with the components in 2-stage reimplantation following infection. Rotating-hinge TKA implants were used for complex primary procedures in 74 knees (18%) and as a revision construct in 334 knees (82%). Clinical outcomes were assessed with the Knee Society scoring system, survivorship analyses, and cumulative incidence of revision. The mean age of the patients at the time of the index arthroplasty was 69 years, and the mean duration of follow-up was 4 years (range, 2 to 12 years). Results: At the most recent follow-up, the mean Knee Society knee score had increased from 51 points preoperatively to 81 points (p < 0.0001), and the mean Knee Society functional score had increased from 26 to 36 points (p < 0.0001). At a mean of 4 years, loosening of components was observed in 13 (3.7%) of 349 knees. At the most recent follow-up, 59 revision procedures and 25 reoperations had been performed. The cumulative incidence of any revision was 9.7% at 2 years and 22.5% at 10 years. The cumulative incidence of revision for aseptic loosening was 1.7% at 2 years and 4.5% at 10 years. Metaphyseal cones were used in 114 knees (28%). Survivorship analysis revealed a trend toward a lower risk of revision (hazard ratio [HR] = 0.69; 95% confidence interval [CI] = 0.39 to 1.22; p = 0.20) and reoperation (HR = 0.51; 95% CI = 0.22 to 1.19; p = 0.12) in patients with metaphyseal cones, despite their use in the most severe of bone defects. Conclusions: Contemporary rotating-hinge TKA implants had a low 10-year cumulative incidence of revision for aseptic loosening of 4.5%. Greater use of metaphyseal fixation has aided this improvement. Patients can expect substantial improvements in clinical outcomes with this revision strategy. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Background: Reliable acetabular fixation in total hip arthroplasty following periacetabular resections is challenging. Tantalum components have been successfully implemented for difficult revision arthroplasties, but, to our knowledge, have not been reported for acetabular reconstruction following oncologic periacetabular resection. The primary purpose of the current study was to determine the early clinical outcomes, complications, and radiographic findings for acetabular reconstruction after oncologic periacetabular resection. In addition, a novel classification scheme for primary periacetabular resections and reconstructions is presented. Methods: We reviewed 10 consecutive patients treated with tantalum acetabular reconstruction following periacetabular resection. All patients had a primary acetabular malignancy including chondrosarcoma (n = 7) and osteosarcoma (n = 3). The cohort included 6 males (60%). The mean age was 54 years (range, 30 to 73 years). The mean follow-up was 59 months (range, 8 to 113 months). Results: At the most recent follow-up, 9 patients were alive and 1 had died of the respective disease. All patients obtained full ambulatory status with the use of gait aids. Postoperative complications included dislocation (n = 3), wound-healing disturbance (n = 1), and deep venous thrombosis (n = 1). Two patients underwent reoperations for recurrent dislocations. The mean postoperative Harris hip score was 75 points (range, 49 to 92 points). Conclusions: Preliminary results of tantalum reconstruction following periacetabular resections provide reasonable improvement in early clinical outcomes and stable fixation in situations with massive bone loss and compromised bone quality. As expected due to the lack of a functioning abductor mechanism from the wide oncologic resection, early dislocations remain a concern. As such, we now consider the primary use of increasing constraint, but it must be balanced with the often compromised host bone. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Aims We compared the outcome of total hip arthroplasty (THA) in obese patients who previously underwent bariatric surgery and those who did not, in a matched cohort study. Patients and Methods There were 47 THAs in the bariatric group (42 patients), and 94 THAs in the comparison group (92 patients). The mean age of the patients was 57 years in both groups (24 to 79) and 57% of the patients in both groups were women. The mean time between bariatric surgery and THA was five years (four months to 12 years) in the bariatric group. The mean follow-up after THA was three years (2 to 9). Results The mean BMI improved from 49.7 kg/m2 (35 to 75) prior to bariatric surgery to 35.3 kg/m2 (21 to 49) at the time of THA (p < 0.001). Patients in the comparison group had an increased risk of re-operation (Hazard Ratio (HR) 3.2; 95% confidence intervals (CI) 1.3 to 9.5, p = 0.01) and revision (HR 5.4; 95% CI 1.5 to 34.5, p = 0.01) when compared with the bariatric group. Conclusion Patients had a dramatic improvement in BMI after bariatric surgery and those with prior bariatric surgery had a lower risk of re-operation and revision in the short- and mid-term after a subsequent THA. Larger prospective studies are required before it can be concluded that this extra surgery should be advised in these patients. Cite this article: Bone Joint J 2016;98-B:1180–4.