Dual-mobility socket in challenging total hip arthroplasty: 2-6 years follow-up.

The success of dual-mobility sockets in achieving implant stability in primary hip replacement is already well established. However, stability cannot always be achieved, especially when dealing with more difficult indications. At our department, 104 dual-mobility sockets (92 uncemented and 12 cemented) were implanted for primary total hip arthroplasty in 97 patients between 2009 and 2013. Indications for hip arthroplasty included primary and secondary coxarthrosis, acetabular and subcapital fractures, avascular necrosis, tumor surgery and metastatic fractures. Although no loosenings were observed, 2 dislocations and 1 infection occurred shortly after surgery. In this challenging group of patients no fixation problems or intraprosthetic dislocations have been observed. The design therefore seems to be a valid alternative to constrained implants, especially in high-risk cases, although dislocation cannot be prevented at all times. Although the findings are very promising, long-term survival studies are mandatory to evaluate intraprosthetic stability and fixation longevity of dual-mobility sockets.

Outcome of patellofemoral arthroplasty, determinants for success.

The primary aim of this study is to document whether patellofemoral arthroplasty is a good treatment option for patellofemoral osteoarthritis and to identify prognostic outcome factors. Secondary aim is to investigate the influence of preoperative tibiofemoral osteoarthritis on the clinical outcome. From 2004 to 2010, 37 Avon patellofemoral prostheses were implanted in 32 patients. Clinical outcome was evaluated with five questionnaires: KOOS, Kujala, VAS, OKS and Satisfaction Score. Radiographs were analyzed using the IWANO and Kellgren-Lawrence classification. To identify determinants of outcome, subgroups were examined according to sex, age, diagnosis, BMI and prior surgery. Patellofemoral arthroplasty is a valuable treatment for patellofemoral osteoarthritis. After prosthesis placement, KOOS, Kujala, VAS and OKS improved significantly (all p < 0.001). Patients with prior patellofemoral surgery were clinically worse (p < 0.05). Patients with preoperative Kellgren-Lawrence grade 2 tibiofemoral osteoarthritis had a significantly worse outcome compared to grade 1 (p < 0.05). Further research is necessary to determine whether patellofemoral arthroplasty is indicated in these patients.

Contamination risk of synovial biopsy cultures in total hip arthroplasty: a prospective review of 100 cases.

INTRODUCTION: Cultures of deep synovial biopsies remain an important tool in diagnosing periprosthetic joint infection, a devastating complication following total hip arthroplasty (THA). Recent reports of unexpected positive intraoperative cultures in aseptic revision arthroplasty, however, challenge the validity and interpretation of these cultures. The aim of this study was to evaluate the contamination risk of synovial biopsy cultures collected intraoperatively during primary THA of healthy subjects. METHODS: Synovial biopsies for culture were collected during primary total hip arthroplasty procedures from 100 consecutive cases. The synovial biopsies were taken within the first 15 minutes after skin incision. Biopsy specimen were cultured on 4 different media for 8 or 15 days. Positive cultures were identified using Maldi-Tof spectrometry. RESULTS: 16 cultures yielded a bacterium, suggesting a false positive result of 16%. The mean time for the cultures to become positive was 6.29 days (standard deviation [SD] 3.90) with a maximum of 15 days. Proprionibacterium acnes and Staphylococcus epidermidis were most commonly cultured with 6 positive results for both bacteria. CONCLUSIONS: Our study yielded a 16% false positive rate in cultures of synovial biopsy taken during primary total hip arthroplasty of healthy subjects, suggesting that contamination risk of these synovial biopsy cultures may be larger than assumed by clinicians.

Foreign body reaction after trapeziectomy and Dacron interposition.

The purpose of this study was to evaluate patients who were treated with trapeziectomy and Dacron interposition in our hospital and to describe the incidence of foreign body reactions. Between 2004 and 2010, 10 women with trapeziometacarpal osteoarthritis underwent Dacron interpositional arthroplasty. One patient had surgery in both hands. Implants were removed in two patients, 5 and 8 years postoperatively. Histological analysis confirmed the presence of a foreign body reaction with giant cells in both cases. At a mean follow-up of 9 years, seven patients with the implant still in place were available for review and clinical examination. Mean DASH score was 32 and mean VAS for pain and satisfaction was 1.6 and 8.8, respectively. Mean grip strength was 11.4kg and mean key pinch strength was 1.5kg. Recent radiographs were available in nine hands. Seven out of nine hands had radiological signs of a foreign body reaction with bone erosion. A severe reaction occurred in three patients. We no longer use the Dacron implant and recommend careful monitoring of all patients in whom this implant has been used.