What is the rate of successful closed reduction of dislocated dual mobility cups following complex revision hip arthroplasty?

PURPOSE: The aim of this study was to assess the difference in success rates of closed reduction in septic and aseptic revision total hip arthroplasty (THA) performed with a dual mobility (DM) implant. Our objective was to answer the following questions: (1) Is there a difference in success rates of closed reduction between septic and aseptic revision THA with a DM implant? (2) Is closed or open reduction more successful in preventing re-dislocation? METHODS: Between January 2009 and October 2021, 924 revisions were performed with a DM implant. All patients presenting to our institution with a dislocation following septic or aseptic revision THA using a cemented DM cup were included in this study. We analyzed 106 cases of dislocation in 74 patients. For all patients, we collected reason for revision, and classified index surgery as septic or aseptic. RESULTS: Overall, 106 dislocations occurred (106/924, 11.5%). Thirty-nine cases (52.7%) had a dislocation after a septic exchange THA, while in 35 patients (47.3%), a dislocation occurred after an aseptic rTHA. In 29 patients (39.2%), successful closed reduction under general anesthesia was feasible, while the majority of cases required open reduction. In 31 of these patients (67.4%), open reduction was combined with a revision arthroplasty. CONCLUSIONS: In case of DM cup dislocation, there is a low success rate of closed reduction. To prevent re-dislocation, total revision leads to a significantly reduced risk compared to open or closed reduction alone. Careful X-ray analysis for a halo sign showing intra-prosthetic DM cup dislocation is mandatory to avoid futile reduction attempts. LEVEL OF EVIDENCE: III.

What is the failure rate of constrained liners in complex revision total hip arthroplasty?

BACKGROUND: Recurrent hip dislocation after multiple revision total hip arthroplasty is a severe complication. Therefore, constrained acetabular liners (CL) have been used during salvage procedures. We report our experience of constrained liners in a re-revision setting with focus on re-dislocation. We also evaluated acetabular and femoral bone loss as potential risk factor. METHODS: Between January 2013 and December 2016, 65 patients were treated in a single institution for revision and re-revision hip arthroplasty using CL. The indication for using a CL was a high risk of re-redislocation after multiple recurrent hip dislocation including failed Dual Mobility Cups (DMC). Compromising soft tissue defects as well as severe bone defect were therefore regarded as high risks. Thirty-eight patients (77.6%) underwent a minimum of three surgical procedures before the index revision procedure. Sixteen patients (24.6%) were excluded as they were lost to follow-up, expired before minimum follow-up or refused study participation, leaving 49 patients in the analysis (75.4%). The mean follow-up was 62 months (44-74; SD = 7.7). We assessed the following potential risk factors for revision or dislocation: type of surgical setting (septic/aseptic), BMI, cup inclination angle, size of liner used and acetabular and femoral bone loss according to Paprosky classification. The primary endpoints were dislocation or repeat revision for any reason. RESULTS: Of the 49 patients, we found an overall re-revision rate of 40.8% (20/49) and a dislocation rate of 30.6% (15/49). There were no significant differences among the surgical re-revision rate or dislocation rate as a factor of patient characteristics. In terms of bone loss, there was a trend towards higher revision rates for increasing acetabular and femoral bone loss, but without statistical significance. CONCLUSIONS: We found the use of a constrained liner in a re-revision setting still bears a high risk of re-revision and re-dislocation. Therefore we restrained from using constrained liners in favour of Dual mobility cups. In this study there was no significant higher dislocation rate in the subgroup of periprosthetic infection. Furthermore the rigid design of a constrained liner bears the known risk of structural failure of acetabular reconstruction implants. Severe acetabular or femoral bone defects seem to have an impact on the revision rate, but not on the dislocation rate with regards to the restored offset and center of the hip. Results have to be taken into context such that the study population inherently has a predisposition for poorer outcomes. Indications should be strongly filtered for patients at high risk for recurrent hip joint dislocation including failed DMCs with only limited bone loss and moderate soft tissue defects. Our modification to the existing classification with a high inter and intraobserver reliability will make future studies more comparable regarding revisions and bone stock loss. Still further research using objective and reproducible parameters is needed to better analyze data especially in the background of complex revision hip arthroplasty.

Total Hip Arthroplasty in a Patient with Mucopolysaccharidosis Type IVB.

Introduction. Morquio syndrome or mucopolysaccharidosis (MPS) type IV is a rare autosomal recessive lysosomal storage disease, characterized by abnormal metabolism of glycosaminoglycans associated with specific skeletal deformities, also known as dysostosis multiplex. Case Presentation. We present the case of a 23-year-old patient with advanced osteonecrosis of the femoral head (ONFH) on both sides due to Morquio syndrome. A diagnosis of mucopolysaccharidosis type IVB was made after extensive genetic profiling. The patient had the condition for a long time. At 7 years old, the patient was treated with bilateral pelvic Salter's osteotomy. Afterward, the patient was able to walk freely but could never take part in sports. At 22 years old, pain in the hip increased, and magnetic resonance imaging showed a bilateral femur head necrosis. Hence, the patient underwent cementless total hip arthroplasty (THA). Intraoperatively, a periprosthetic fracture occurred. Therefore, revision surgery with internal fixation was performed on the next day. Postoperatively, a weight-bearing restriction of 20 kg on the left leg was imposed for 6 weeks. The patient made a full recovery and was able to move without residual complaints. Annual orthopedic evaluation in patients treated with surgical intervention is recommended. Discussion. Orthopedic challenges for mucopolysaccharidoses and corresponding bone alterations, known as dysostosis multiplex, involving trunk and limbs with typical radiological findings have been well described. The hip is invariably involved, with dysplasia affecting the femoral neck (coxa valga), femoral epiphysis (loss of sphericity, osteonecrosis), and a flared hypoplastic iliac wing. Symptomatic therapy consists, on the one hand, of a surgical procedure and, on the other hand, a variety of supportive measures. However, the management of joint replacement in lysosomal storage diseases has not been well reported. All patients with MPS should be considered at high risk for surgical intervention requiring anesthesia because of airway and cardiac disease manifestations. In the case of a need for THA, we recommend cemented stem fixation because of the overall poor bone quality in patients with Morquio syndrome.

What Is the Dislocation and Revision Rate of Dual-mobility Cups Used in Complex Revision THAs?

BACKGROUND: Dual-mobility cups have been shown to reduce the dislocation risk after THA. Although dual-mobility cups can be a useful strategy to mitigate against recurrent dislocation after revision surgery, few clinical studies have focused on the results of complex revision THAs with extensive bone and soft-tissue loss or in patients who have undergone more than one previous surgical procedure. QUESTIONS/PURPOSES: (1) What is the survival free from revision for dislocation of dual-mobility cups used in complex revision THAs? (2) What is the survival free from any dislocation? METHODS: Between January 1, 2009 and December 31, 2013, 327 patients underwent a complex revision THA that included an acetabular revision, defined as preexisting massive bone loss in the acetabulum (at least Paprosky Type 2B) and/or proximal femur (at least Paprosky Type 3), substantial gluteal soft-tissue involvement, at least two previous surgical procedures or a one-stage septic revision, or history of dislocation. All 327 complex revision patients received a dual-mobility cup. Of those, 34% (111) were lost to follow-up before 5 years and were not known to have reached a study endpoint (revision for dislocation, and any dislocation) before then, leaving 216 patients for analysis. For patients with bilateral hip surgeries only the first operated hip was included for analysis. The median (range) follow-up duration was 69 months (60 to 110). The primary endpoint was dislocation or re-revision for dislocation. Fifty-six percent (120 of 216) of the patients were women and 44% (96 of 216) were men. The mean age of the patients was 69 ± 9 years. The patients underwent a median of four surgical procedures (1 to 4) before the index procedure (the revision evaluated in this study). A survival analysis was performed using the Kaplan-Meier method; any dislocation or revision for dislocation was determined as the endpoint. RESULTS: The dislocation-free survival rates were 96% (95% confidence interval 92 to 98) at 5 years and 82% (95% CI 72 to 89) at 9 years. The overall dislocation rate was 11% (24 of 216 patients) at the final follow-up interval. Survival free of revision for dislocation was 99% (95% CI 96 to 100) at 5 years and 85% (95% CI 75 to 92) at 9 years. CONCLUSIONS: Dual-mobility cups used in complex revision THA in this series had a higher rate of dislocation and revision than expected, based on earlier studies of dislocations of these components. Although we believe dual-mobility cups are still the first choice of implant if the patient has instability, these cups should be used cautiously if severe bone loss or soft-tissue involvement is present. LEVEL OF EVIDENCE: Level III, therapeutic study.

What Is the Diagnostic Accuracy of Alpha-Defensin and Leukocyte Esterase Test in Periprosthetic Shoulder Infection?

BACKGROUND: The diagnosis of periprosthetic joint infection (PJI) after total shoulder arthroplasty (TSA) is challenging, especially in patients with Cutibacterium (formerly Propionibacterium) acnes infection. Despite the increasing number of patients with PJI of the shoulder, there are still no robust data regarding diagnostic tests in detecting shoulder PJI. QUESTIONS/PURPOSES: (1) What are the sensitivity, specificity, and negative- and positive-predictive values for the alpha-defensin enzyme-linked immunosorbent assay test in detecting PJI after TSA? (2) What are the diagnostic accuracies in detecting shoulder PJI for synovial alpha-defensin, leukocyte esterase Test, and serum C-reactive protein (CRP)? METHODS: All patients with painful TSA, who underwent joint aspiration to validate or exclude a PJI, between July 2015 and February 2018 were enrolled in this single-center study. Further indications for aspiration were as follows: planned revision arthroplasty, early loosening and clinical signs of infections, especially serum CRP elevation. A total of 121 patients were aspirated to exclude or verify a PJI, and 16 patients were excluded. In all, 105 patients with a mean age of 68 years (± 12 years) were included for analysis. Patients who underwent TSA were considered aseptic or septic according to the Musculoskeletal Infection Society criteria. Twenty-four patients had a PJI, and the remaining 81 patients were in the aseptic group. The microbiologic evaluation including polymicrobial infection showed C. (formerly P.) acnes in 15 patients (63%). Synovial fluid was then analyzed using microbiology cultures, alpha-defensin immunoassay, and leukocyte esterase. The specificity, sensitivity, and positive-predictive and negative-predictive values were calculated for each test. RESULTS: The overall accuracy for alpha-defensin was 91% (95% confidence interval [CI], 84.4-96); sensitivity was 75% (95% CI, 53-90), specificity was 96% (95% CI, 90-99), negative predictive value was 93% (95% CI, 85-97), and positive predictive value was 86% (95% CI, 64-97). In contrast, the overall accuracy for leukocyte esterase was 76% (95% CI, 61-88), sensitivity was 50% (95% CI, 21-79), specificity was 87% (95% CI, 69-96), positive predictive value 60% (95% CI, 26-88) and negative predictive value was 81% (95% CI, 64-93). CONCLUSIONS: Summarizing the study results, the alpha-defensin ELISA and leukocyte esterase tests had less sensitivity in detecting shoulder PJI than previously reported TKA or THA results. The quality and low amount of joint fluid is the difficult part of the diagnostic. C. (formerly P.) acnes was the most common cause of PJI. Focusing on low-grade infections, alpha-defensin has shown its advantages in diagnosing PJI regardless pathogen virulence. Since the diagnostic of a PJI is always a synopsis of findings, the alpha-defensin and leukocyte esterase test can be used as adjunct diagnostic tool in patients with painful TSA. We propose further prospective studies to improve the diagnostic and confirm the results. LEVEL OF EVIDENCE: Level III, diagnostic study.

Serum C-reactive protein relationship in high- versus low-virulence pathogens in the diagnosis of periprosthetic joint infection.

Little is known about the relationship between the virulence of pathogens in periprosthetic joint infection (PJI) and C-reactive protein (CRP) levels. In this context, we assessed the performance of CRP for PJI. We collected the following data from 987 cases of total joint revision due to PJI and 386 cases of aseptic revision: age, gender, comorbidities, values for serum CRP, leukocytes, microbiology for preoperatively taken aspirations and at least 2 intraoperative biopsies, and presence or absence of a draining sinus. The mean CRP value in the PJI group was 50.2 mg l-1 (sd=62.2), while a lower CRP value of 11.6 mg l-1 (sd=25.3) was found in the control group. There were no significant differences for the CRP values between patients with and without draining sinus (P=0.4423). The difference in CRP between high-virulence and low-virulence micro-organisms was significant for both the hip and the knee (P<0.0001). For the hip, the area under the receiver operating characteristic curve (AUC) of CRP as a diagnostic marker for PJI was 0.830 and, for the knee, the AUC was 0.884. The optimal cutoff point for CRP as a diagnostic marker of PJI, calculated using Youden's index, was 8.90 mg l-1 for the hip and 9.99 mg l-1 for the knee. The study results add valuable new information regarding the organism profile that may help with the diagnostic workup and with the research and development of new strategies for diagnosing and treating PJI.