Effective prevention of recurrent dislocation following primary cemented Endo-MarkIII/SP2 total hip arthroplasty using a posterior lip augmentation device.

PURPOSE: This retrospective study was performed to determine the effectiveness of preventing recurrent dislocation following primary cemented Endo-MarkIII/SP2 total hip replacement using a posterior lip augmentation device (PLAD). METHODS: Between January 2003 and Dezember 2006, 27 PLADs were used in the treatment of recurrent hip dislocation in 27 patients who had received a cemented primary total hip arthroplasty using Endo-MarkIII/SP2 (Waldemar LINK, Hamburg, Germany) components. The mean number of dislocations prior to stabilization with this specific device was 2.6 (range 2-4, SD ± 0.4) with a mean time to revision surgery of 10 months (IQR 13). The mean age of the patients at time of revision surgery was 81.5 years (range 70-94, SD ± 6.9). The control group evaluating the clinical outcome using the Harris Hip Score (HHS) also received a cemented primary total hip arthroplasty using the same implants. A retrospective clinical and radiological review was carried out at a mean follow-up of 68.5 months (range 30-103, SD ± 17.7). RESULTS: Of the 27 patients, 6 had died at the time of the latest review, with the posterior lip augmentation device still in situ and without reported further dislocation after PLAD application. In 2 of the remaining 21 patients recurrent dislocation occurred, thus a subsequent revision of respective implants had to be performed to achieve persistent joint stability. At latest follow-up no deep infection or implant loosening occurred. CONCLUSION: Surgical treatment of recurrent dislocation following primary cemented Endo-MarkIII/SP2 total hip replacement using a posterior lip augmentation device is a safe and effective procedure which can lead to a secondary stabilization of the total hip arthroplasty in about 90 % of the patients.

Increased risk for extended acetabular reconstruction in failed hip resurfacing as compared to failed total hip arthroplasty.

INTRODUCTION: Hip resurfacing (HR) is intended to preserve the femoral bone stock during primary arthroplasty. On the other hand, little has been reported regarding the intraoperative need of bone reconstruction for extended acetabular defects during hip resurfacing revision. Thus, the aim of the presented study was to identify whether there is an increased need for acetabular bone reconstruction in HR revision surgery. MATERIALS AND METHODS: We analyzed the data of 38 patients who underwent 39 conversions from a HR to a total hip arthroplasty (THA). Acetabular bone defects and the respective revision technique were compared against a temporary cohort of patients undergoing revision surgery of a conventional THA. RESULTS: In 29 HR patients revision required either autogenous or allogenous impaction bone grafting to adequately manage acetabular host bone degradation. In 10 cases additional implantation of a reinforcement device was necessary. Compared to the THA cohort revision of failed HR is associated with a significantly increased risk of higher grade bone defects (Paprosky classification) and extended acetabular reconstruction (p < 0.05). CONCLUSIONS: This study provides evidence that revision of failed HR devices is associated with an increased risk for extensive acetabular defects. Furthermore, the preoperative radiographic assessment of HR devices often underestimates the intraoperative acetabular defect. Surgeons should be aware of this fact not to technically underestimate HR revision procedures.

[The use of tantalum cones for reconstruction of bone defects in revision total knee arthroplasty]. / Defektrekonstruktion beim Knieendoprothesenwechsel mit Tantal-Konen.

OBJECTIVE: Revision arthroplasty of the knee is often associated with substantial femoral and/or tibial bone loss. Tantalum cones are used to reconstruct these defects and to improve initial stability. This requires an implantation in the "press-fit" technique with maximum contact to the host bone. INDICATIONS: Tantalum cones may be used in grade 2-3 femoral and/or tibial defects according to the AORI (Anderson Orthopedic Research Institute) classification system. CONTRAINDICATIONS: There are no contraindications described. SURGICAL TECHNIQUE: After removal of the implant and cement remnants, bone defects have to be evaluated. A tantalum cone which adequately fills the bone defect is implanted using the "press-fit" technique. If necessary, saving resection of surplus bone to fit the cone properly. Gaps between the cone and the host bone are filled with cancellous bone in "impaction-bone-grafting" technique to increase the area of contact. Fitting the revision knee prosthesis and fixing with the use of bone cement. POSTOPERATIVE MANAGEMENT: Postoperative physiotherapy is adjusted to the result of the reconstruction. In most cases with stable reconstruction, mobilization with full weight-bearing and the use of two crutches can be performed. Additional bone grafting may require a partial weight-bearing regimen for postoperative mobilization. Physiotherapy to improve range of motion is performed starting on postoperative day 1. RESULTS: Several studies reported promising midterm results (observation period about 36 months) after implantation of tantalum cones in revision knee arthroplasty. There is consistent evidence for stable osteointegration of the cones. The main intraoperative complication is fracture of the host bone during impaction of the cones.