Retrieval Analysis of Polyethylene Components in Rotating Hinge Knee Arthroplasty Implants.

BACKGROUND: This study examined a cohort of retrieved rotating hinge (RH) total knee arthroplasty implants of four different designs with emphasis on the surface damage observed on the polyethylene components. Our purpose was to determine if differences in polyethylene damage existed among the designs, and if those differences could be explained by differences in design characteristics. MATERIALS AND METHODS: Seventy-two RH implants from four manufacturers (DePuy LPS/SROM, Zimmer NexGen, Stryker Howmedica MRH, and Biomet Finn-OSS) removed at the time of revision performed between 2002 and 2017 were identified in our institutional retrieval registry. Damage to the surfaces of the polyethylene was assessed using a subjective grading system and evaluated in multiple zones. Design characteristics that were evaluated included the following: location of the dwell point on the polyethylene component, posterior position of the axle, and amount of hyperextension and rotation allowed by the implant. RESULTS: There were no differences in total damage scores between the four implant groups (P = .45). The Stryker Howmedica MRH group showed the least backside wear of all implants but significantly more articular-sided wear compared with two of the other three groups. All implants except NexGen showed increased total damage scores in implants revised for mechanical (vs nonmechanical) reasons and in implants with a longer duration of implantation. CONCLUSION: No single implant design emerged as superior in terms of minimizing polyethylene wear damage. Polyethylene damage existed in various locations but was not different in severity across designs, suggesting that there is no clear superior RH design that minimizes overall articular surface wear compared with other designs.

Five-Year Follow-Up of Clinical Outcomes with an Anatomic Dual-Mobility Acetabular System: A Multicenter Study.

BACKGROUND: The dual-mobility implant system has been shown to increase impingement-free range of motion and decrease dislocation risk by increasing the effective head size. In addition, the anatomic dual-mobility (ADM) cup offers relief between the acetabular shell rim and the iliopsoas tendon. This study was designed to review a series of hips implanted with the ADM acetabular cup to examine clinical outcomes after 5 years of implantation at multiple orthopaedic centers. METHODS: We retrospectively queried our prospectively collected total joint arthroplasty registry for patients who underwent total hip arthroplasty with an ADM cup from January 2008 to December 2012 at 4 different orthopaedic institutions and who had minimum 5-year follow-up. Harris Hip Scores and visual analog scale scores were evaluated. Postoperative complications, dislocations, and revisions for any reason were recorded. RESULTS: A total of 142 patients had a mean follow-up of 5.7 years (range: 5.0 to 8.0 years). Radiographic analysis showed no radiolucent lines, osteolysis, or acetabular loosening. There were no dislocations in this patient series. Two (1.2%) hips required a revision because of adverse local tissue reactions related to corrosion from a recalled modular neck stem, but this was unrelated to the ADM cup. The mean Harris Hip pain scores increased from 17 points preoperatively to 39 points at the most recent follow-up (P < .001). The mean Harris Hip function score increased from an average of 29 points preoperatively to 38 points at the most recent follow-up (P < .001). The mean visual analog scale score showed patient improvement from 6.5 preoperatively to 1.2 postoperatively (P < .001). CONCLUSIONS: ADM prostheses were designed to reduce the risk of dislocation by increasing the size of the effective femoral head. In this multicenter study of ADM cups used in primary total hip arthroplasty, we demonstrated good clinical and radiographic outcomes, no dislocations, and no revisions at midterm 5-year minimum follow-up. Patient-reported outcome measures were also improved, supporting the use of this implant.

Multicenter Evaluation of a Modular Dual Mobility Construct for Revision Total Hip Arthroplasty.

INTRODUCTION: Modular Dual Mobility (MDM) constructs in total hip arthroplasty (THA) offer increased hip stability compared with constrained liners, without compromising hip range of motion. The purpose of this study was to evaluate outcomes of revision THA using MDM. METHODS: The study was a multiinstitutional retrospective cohort study of 315 hips that underwent revision THA using MDM between 2011 and 2017. Clinical outcomes and reasons for failure were collected. RESULTS: Three hundred fifteen patients met 1-year minimum follow-up (mean 3.3 years). Nine hips had instability postoperatively (2.9%), and 30 hips required reoperation (9.5%). Seven had recurrent instability (6.5%) which was associated with liner-only exchange (P = .021) and liner outer diameter of ≤ 38 mm (P = .016). CONCLUSION: Revision THA with MDM provided a low rate of instability and reoperation in a revision cohort. Recurrent instability following use of MDM in revision THA was associated with retention of the acetabular component and polyethylene outer diameter ≤ 38 mm. LEVEL OF EVIDENCE: Therapeutic Level III.

The Use of Aspirin for Prophylaxis Against Venous Thromboembolism Decreases Mortality Following Primary Total Joint Arthroplasty.

BACKGROUND: The use of aspirin as prophylaxis against venous thromboembolism (VTE) following total joint arthroplasty (TJA) has increased in popularity; however, the potential cardioprotective effects of aspirin when administered as VTE prophylaxis remain unknown. The present study investigated the influence of VTE prophylaxis, including aspirin, on mortality following TJA. METHODS: We retrospectively reviewed 31,133 patients who underwent primary TJA from 2000 to 2017. Patient demographics, body mass index, and comorbidities were obtained from an electronic chart query. Patients were allocated into 2 cohorts on the basis of the VTE prophylaxis administered: aspirin (25.9%, 8,061 patients) and non-aspirin (74.1%, 23,072 patients). Mortality was assessed with use of an institutional mortality database that is updated biannually. Univariate and multivariate regression analyses were performed. RESULTS: The overall mortality rate was 0.2% and 0.6% at 30 days and 1 year after TJA, respectively. The use of aspirin was independently associated with lower risk of death at both 30 days (odds ratio [OR], 0.39; p = 0.020) and 1 year (OR, 0.51; p = 0.004). Patients in the non-aspirin cohort showed 3 times the risk of death at 30 days compared with the aspirin cohort (0.3% compared with 0.1%; p = 0.004), and twice the risk of death at 1 year (0.7% compared with 0.3%; p < 0.001). At 1 year, the primary cause of death in the non-aspirin group was cardiac-related (46 of 23,072, 0.20%). In the aspirin group, the rate of cardiac-related death was almost 5 times lower (3 of 8,061, 0.04%; p = 0.005). Risk factors for mortality at 1 year included higher age (p < 0.001), male sex (p = 0.020), history of congestive heart failure (p = 0.003), cerebrovascular disease (p < 0.001), malignancy (p < 0.001), and history of prior myocardial infarction (p < 0.001). CONCLUSIONS: The present study demonstrates that the use of aspirin as prophylaxis against VTE following TJA may reduce the risk of mortality. Given the numerous options available and permitted by the current guidelines, orthopaedic surgeons should be aware of the potential added benefits of aspirin when selecting a VTE-prophylactic agent. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Aspirin Is as Effective as and Safer Than Warfarin for Patients at Higher Risk of Venous Thromboembolism Undergoing Total Joint Arthroplasty.

BACKGROUND: There is continued controversy regarding the optimal venous thromboembolism (VTE) prophylaxis, particularly for total joint arthroplasty (TJA) patients at higher risk. The purpose of this study was to compare the efficacy of aspirin (ASA) to warfarin in patients with higher risk of VTE. METHODS: This retrospective study examined 30,270 patients who received ASA or warfarin for VTE prophylaxis after TJA. Using a previously developed risk stratification model, patients were classified into low or high VTE risk categories. Postoperative 90-day VTE, periprosthetic joint infection (PJI), gastrointestinal complications, and mortality were recorded. RESULTS: The incidences of VTE, PJI, and mortality were higher in patients receiving warfarin compared to ASA. In multivariate analysis, warfarin was an independent risk factor for VTE, PJI, and mortality in the higher risk VTE patients (P < .001). There was no significant difference in gastrointestinal complications between groups. CONCLUSION: Our study demonstrates that ASA is as effective as and safer than warfarin for VTE prophylaxis after TJA, even in patients at higher risk of VTE.

Total joint arthroplasty in cancer patients.

Increasing numbers of total joint arthroplasty (TJA) patients have a history, or an active diagnosis, of cancer. We aimed to evaluate the risk of early postoperative complications in these patients. In our series, a history of malignancy was associated with an elevated risk of ischemic cardiac events and postoperative deep vein thrombosis (DVT), while active malignancy was associated with increased respiratory and renal complications, hematoma/seroma formation and early postoperative mortality. Both groups presented increased rates of overall in-hospital complications. Patients with bone metastasis to the hip demonstrated increased DVT and 90-day mortality rates. Cancer patients have increased morbidity and mortality after TJA and should undergo comprehensive medical optimization and adapted thromboprophylaxis.

Staged Bilateral Total Knee Arthroplasty: Time of the Second Side.

The purpose of this study was to determine if there was a safe time frame for performing the second total knee arthroplasty (TKA) in staged bilateral TKAs. Retrospectively, 589 TKAs were studied at a single institution from January 2000 to June 2012. Patients were excluded if they underwent simultaneous or staggered bilateral TKA during the same hospitalization. Patients were included if they underwent bilateral staged TKA during a different hospitalization within 21 to 90, 91 to 180, 181 to 270, and 271 to 360 days after the first TKA. In-hospital complications were determined using International Classification of Diseases, Ninth Revision codes for cardiac, pulmonary, urinary, deep vein thrombosis, wound complications, mechanical complications, and wound infections. Periprosthetic joint infection (PJI) was determined by hospital readmission records. There were 29 postoperative complication events (4.9%) and there was no difference between time groups and complications. The highest rates of PJI occurred when the second TKA was performed after 271 to 360 days (3.6%), followed by the early postoperative period after 21 to 90 days (2.7%). We could not identify a time frame for performing the second TKA in staged bilateral TKAs to reduce complications. A signal from the study suggests that complications, particularly PJI, may be lower if the second TKA is performed more than 90 days and less than 270 days after the first TKA, although this finding was not significant.

Total joint arthroplasty: should patients have preoperative dental clearance?

Obtaining dental clearance prior to elective total joint arthroplasty is a common practice; however, little published data exist to justify this requirement. Dental clearance data for 365 elective total knee and total hip arthroplasty patients were gathered prospectively. Of these patients, 358 (average age of 62.4 years; 157 men and 201 women; 152 primary total knee arthroplasties (TKAs), 16 revision TKA arthroplasties, one conversion TKA, 168 primary total hip (THAs) arthroplasties and 21 revision THA arthroplasties) proceeded to surgery and follow-up data were available for 355. A comparison group of 218 hip fracture patients (average age of 78.7 years; 52 men and 109 women; 137 THA and 81 hemiarthroplasties) with no preoperative dental clearance who were treated with hip arthroplasty was extracted retrospectively from an institutional database. Follow-up data were available for 161 of these patients. The incidence of dental pathology in the elective arthroplasty group was 8.8%. Early postoperative infection requiring surgical treatment occurred in six patients (1.7%) in the dental clearance elective arthroplasty group and in four patients (2.5%) in the hip fracture arthroplasty group. No statistical difference was found between the two groups. This suggests that the perceived need for routine preoperative dental screening for all hip and knee arthroplasty patients should be reassessed.