An abnormal lateral position of the tibial tuberosity causes distal malalignment of the extensor mechanism of the knee and can lead to lateral tracking of the patella causing anterior knee pain or objective patellar instability, characterised by recurrent dislocation. Computer tomography is used for a precise pre-operative assessment of the tibial tubercle-trochlear groove distance. A distance of more than 15 mm is considered to be pathological and an indication for surgery in symptomatic patients. In a prospective study we performed a subtle transfer of the tibial tuberosity according to the information gained from the pre-operative CT scan. This method was applied to two groups of patients, those with painful lateral tracking of the patella, and those with objective patellar instability. We evaluated the clinical results in 30 patients in each group. The outcome was documented at 3, 12 and 24 months using the Lysholm scale, the Kujala score, and a visual analogue pain score. Post-operatively, all but one patient in the instability group who had a patellar dislocation requiring further surgery reported good improvement with no further subluxation or dislocation. All patients in both groups had a marked improvement in pain and functional score. Two patients sustained a tibial fracture six and seven weeks after surgery. One patient suffered a per-operative fracture of the tibial tubercle which later required further fixation. If carefully performed, this type of transfer of the tibial tubercle appears to be a satisfactory technique for the treatment of patients with an increased tibial tubercle-trochlear groove distance and who present with symptoms related to lateral maltracking of the patella.

In patients with either lateral tracking patella or unstable patella the pathological lateral position of the tuberosity can be corrected by a medial transfer. This study compared the results of subtle CT-guided correction of the tuberosity for objective unstable patella (n=27) with the results for lateral tracking patella (potential instability) as described by Dejour (n=16). Follow-up was 37 months. CT revealed a pathological lateralization of the tibial tuberosity-trochlear groove greater than 15 mm in 41 knees. These patients underwent medialization of the tibial tuberosity up to 10-12 mm lateral from the trochlear groove, and 28 patients underwent a distalization to normalize the Caton index to 1.0-1.2. Results were evaluated using Cox' method. Patients with objective patellar instability were rated as 11% excellent, 52% good, 33% fair, and 4% poor. All patients became stable except one who had a 6 degrees valgus alignment. Although 96% had improved stability, 33% of the patients still had pain. The patients with lateral tracking patella (potential instability) were rated as 37.5% excellent, 44% good, and 19% fair. The lower proportion of pain relief in patients with unstable patella is likely the result of the cartilage damage experienced by these patients following multiple dislocations. Thus the patient with lateral tracking patella without patella dislocations must be differentiated from the one with unstable patella. Their prognosis in pain relief is better.

The purpose of this study is to evaluate the clinical and radiological results and the survival of the SAL II mobile bearing knee prosthesis at 5-year follow up. Between February 1995 and March 1998 a total of 246 SAL II total knee arthroplasties were performed in 232 patients. The mean follow up was 5.0 years. Thirteen revisions had been carried out (5%). The mean total Knee Society Score increased from 88 preoperatively to 153 and 155 at 1 and 5 years follow up, respectively. The mean flexion angles were 106 degrees and 107 degrees pre- and postoperatively. None of the prostheses showed radiological loosening. No dislocations or subluxations of inserts were seen. The Kaplan-Meier cumulative survival is 95% for revision for any reason at 5.0 years, with a worst case scenario of 91%. The survival for aseptic loosening is 99%. The results of SAL II after a minimum follow up of 5 years are favourable and comparable with fixed bearing and other mobile bearing designs in terms of Knee Society Score and survival. Noteworthy are the good radiological results of this device which showed a good fixation of the prosthesis at 5 years.

This study evaluates the incidence of revision of the monoblock, uncemented, titanium-coated RM (Robert Mathys) cup (Mathys Medical, Bettlach, Switzerland) in primary total hip arthroplasty. Between 1991 and 1995 a total of 630 RM cups were implanted in 462 patients. A Kaplan-Meier survival analysis was performed with failure defined as acetabular revision for any reason. The mean follow-up was 8.2 years. A total of 34 acetabular revisions (5%) were carried out: 15 for recurrent dislocation due to cup malposition, nine for wear caused by impingement of a loose femoral component, five for aseptic loosening, only one cup was revised for articular polyethylene wear, and four for other causes. The cumulative survival rate of the RM cup is 91% at 10.7 years, with a worst case scenario of 87%. The cumulative survival rate for aseptic loosening was calculated: 99% at 10.7 years. The titanium-coated RM cup shows an impressive survival rate with revision for aseptic loosening as endpoint. Correct cup positioning is the key to success and requires experience and meticulous surgical technique. (Hip International 2005; 15: 71-7).

This study evaluates the incidence of revision of the monoblock, uncemented, titanium-coated RM (Robert Mathys) cup (Mathys Medical, Bettlach, Switzerland) in primary total hip arthroplasty. Between 1991 and 1995 a total of 630 RM cups were implanted in 462 patients. A Kaplan-Meier survival analysis was performed with failure defined as acetabular revision for any reason. The mean follow-up was 8.2 years. A total of 34 acetabular revisions (5%) were carried out: 15 for recurrent dislocation due to cup malposition, nine for wear caused by impingement of a loose femoral component, five for aseptic loosening, only one cup was revised for articular polyethylene wear, and four for other causes. The cumulative survival rate of the RM cup is 91% at 10.7 years, with a worst case scenario of 87%. The cumulative survival rate for aseptic loosening was calculated: 99% at 10.7 years. The titanium-coated RM cup shows an impressive survival rate with revision for aseptic loosening as endpoint. Correct cup positioning is the key to success and requires experience and meticulous surgical technique. (Hip International 2005; 15: 71-7).

Aseptic loosening in total hip arthroplasty can lead to proximal femoral periprosthetic bone loss. The non-cemented Wagner revision stem achieves primary fixation in the diaphysis. The purpose of this study is to evaluate the results after medium- to long-term follow-up of the Wagner prosthesis for revision of the femoral component for aseptic loosening in total hip arthroplasty with proximal femoral bone loss. We performed 53 femoral revisions for aseptic loosening with the non-cemented Wagner revision stem. Clinical assessment included a modified Harris Hip Score and a radiological evaluation. The mean follow-up was 65 months. The Harris Hip Score improved significantly (42.9 to 72.3). Radiological evaluation revealed 24.5% subsidence (>5 mm) in our population. Nine re-revisions were done, eight in the first post-operative year. The re-revisions were performed for progressive subsidence (five), recurrent dislocations (one), subsidence with low-grade infection (one), false route (one), and aseptic loosening after 75 months (one). The cumulative survival rate of the Wagner stem after 12 months was 85% and 76% after 75 months. A relatively high re-revision rate was observed during the first post-operative year. Analysis of these failures has shown that subsidence may be the result of insufficient primary stability. Adequate pre-operative planning and intra-operative radiological assistance is necessary for perfect primary stability and fixation of the Wagner stem. The re-revision incidence after the first 12 months is 0.45 per 100 implants per year. The prosthesis has good survival potential after proper introduction.