We cross-matched the Swedish Hip and Knee Arthroplasty Registers (SHAR and SKAR) to study the incidence of knee or hip arthroplasty in any of the remaining hip or knee joints. 177835 THR (55.8% females, mean age, At the index operation more patients were operated on their right side for both locations (hip and knee). Patients who at the index operation had been operated with a TKR and especially on the left side most frequently (32.5%) received one or several additional TKR or THR. For patients who had a THR at their index operation and underwent a second operation of any of the remaining three joints the mean time to this second procedure was 4.0 years ( In patients who had undergone their first (index) operation of either hip the probability of not being subjected to further arthroplasty operations during the following 20 years amounted to 64.0±0.3%. The corresponding probability for patients who at the index operation had received a TKR was somewhat lower (58.4±0.4%). Decreasing age (HR: 1.029, 95% confidence interval: During our period of observation 25 to 33 percent of the patients who received their first total hip or knee replacement underwent at least one additional replacement of either the hip or the knee. Knee osteoarthritis more frequently results in staged bilateral joint replacement than in patients who primarily are suffering from osteoarthritis of the hip.
The median follow-up time was 6 (5–11) years. The median VAS for pain for the affected hip was 0 (0–5) at rest and 0 (0–9) at movement. The median HHS at follow-up was 78 (16–100) points. 17 (19%) patients dislocated their hips during follow-up. A prosthesis head size of 22 mm was present in 6/17 (35%) patients with dislocation and in 11/73 (15%) patients without dislocation (P = 0.055). The cumulative 5 year survival rate was 98% (95% CI: 94–100%) with stem removal and 90% (95% CI: 85–96%) with any reoperation as the endpoint. At follow-up, we noted subjectively that 17% of the cases had evidence of proximal bone restoration, whereas 44% had constant defects. In 39% the quality of the proximal bone appeared to be declining. If present, this was mostly seen around the lesser trochanter. The median vertical stem migration was 2.7 (0–30) mm
The manufacturer of the MP hip stem recommends a distal femoral implant/bone anchorage of at least 80 mm to gain implant stability. However, there are no in vivo studies showing that this fixation length is achieved in clinical practice and that this distance is needed for clinical satisfying results. Therefore, the aim of this study was to assess the distal femoral fixation length of the MP reconstruction prosthesis by using computer assisted tomography (CT).
The median length of femoral stem/bone anchorage was 33 mm (IQR 10–60) which was too short according to the manufacturer’s guidelines. Still, all patients were fully weight-bearing and only 1/14 complaint about mild thigh pain. 7/14 patients did not experience any pain at rest or movement in the affected hip. The patients reached median 85 (IQR 77–94) points in the HHS, corresponding to a good result. At 62 months follow-up, the patients described the same pain scores and the HHS had still a good result with 81 (IQR 62–92) points.