Revision TKA can be a difficult and complex procedure. Bone quality is commonly compromised and stem fixation is required in many cases to provide stability of the prosthetic construct. However, utilization of diaphyseal engaging stems adds complexity to the case and can present technical challenges to the surgeon. Press fit metaphyseal sleeves can provide stable fixation of the construct without the need for stems and allows for biologic ingrowth of the prosthesis. Metaphyseal sleeves simplify the revision procedure by avoiding the need to prepare the diaphysis for stems, alleviating the need for offset stems and decreasing the risk of intra-operative complications. The ability to obtain biologic fixation in the young patient is also appealing. This study reports on the author's mid-term experience with this novel technique. Between May 2007 and June 2009 the author performed 17 revisions TKA that utilized press-fit metaphyseal sleeves without stems on either the tibial side of the joint, the femoral side of the joint or both. Twenty six sleeves were implanted altogether (13 tibial, 13 femoral). Patients were limited to touch down weight bearing for 6 weeks post-operatively. The patients were followed prospectively with clinical and radiographic follow-up at routine intervals.Introduction
Methods
Modern acetabular shells have many liner options from which the surgeon can choose to most appropriately reconstruct the arthritic hip. Lateralised liners are one option that is available to the surgeon and these liners have potential benefits over “standard” polyethylene liners. Benefits include decreased Von Mises stresses which may lead to decreased polyethylene wear, lateralisation of the femur away from the pelvis which can decrease impingement / increase ROM and having the ability to use larger femoral heads in a smaller shell improving stability of the THA. Despite these benefits, lateralised liners are not routinely used by surgeons as there is concern over lateralisation of the centre of rotation of the hip with increased joint reaction forces, unsupported polyethylene that could lead to liner failure, and a slightly increased torque moment to the shell which could lead to micromotion and failure of the shell to obtain bony ingrowth. This study reports on 5-year minimum clinical and radiographic F/U of a prospective series of lateralised, moderately crosslinked polyethylene liners. 102 consecutive patients who were to have a THA with a polyethylene liner were enrolled prospectively in an acetabular shell study. Two patients that had standard thickness liners were excluded from this analysis. The remaining 100 patients all had +4 lateralised liners of the same construct (Marathon polyethylene / Pinnacle Cup, DePuy, Warsaw, Indiana). All surgeries were performed by the same surgeon via a posterior approach. A neutral or 10 degree face changing liner was chosen based on shell position and stability of the THA construct. Patient data including the Harris Hip Score (HHS), WOMAC and ROM was collected at 3, 6 and 12 months and yearly thereafter. Radiographs were obtained at each visit.Introduction
Methods
Metal on metal hip bearings (MoM) are under scrutiny. Short and mid-term complications attributed to metal wear debris have been reported. Distinctions between MoM prostheses exist. Thus, generalizing findings from one design to another is questionable. This study reports minimum 5 yr. Pinnacle™ modular MoM results. Between September 2001 and October 2004, 95 consecutive MoM THAs were performed by one surgeon in a prospective cohort design. Mean age was 53 yrs (range 34-70); 57 were male. Mean BMI was 29 (range 20-46). OA was noted in 87 patients. Head size was 28mm in 3 and 36mm in 92. Surgical approach was postero-lateral in all patients. Harris Hip Score (HHS), WOMAC, ROM and radiographs were evaluated preoperatively, at 6-months, and yearly thereafter.Introduction
Methods
With numbers available, there were no differences between the groups with regard to change in KSS (p=0.38), ROM (p=0.42), mean postoperative anatomic alignment (5.78° vs. 5.50°, p=0.37), femoral angle (5.56° vs. 5.61°, p=0.84), or tibial angle (89.89° vs. 89.69°, p=0.46). There was a non-significant trend towards fewer outliers in the CASTKA group with respect to anatomic alignment (2.8% vs. 13.9%, p=0.09) and tibial angle (0% vs. 5.6%, p=0.46).
