The Bernese Periacetabular Osteotomy (PAO) has become the established method for treating developmental dysplasia of the hip. In the 1990s, the surgical technique was modified to avoid postoperative cam impingement due to uncorrected head neck offset or pincer impingement due to acetabular retroversion after reorientation. The goal of the study was to compare the survivorship of two series of PAOs with and without the modifications of the surgical technique and to calculate predictive factors for a poor outcome. A retrospective, comparative study of two consecutive series of PAOs with a minimum follow-up of 10 years was carried out. Series A included 75 PAOs performed between 1984 and 1987 and represent the first cases of PAO. Series B included 90 hips that underwent PAO between 1997 and 2000. In this series, emphasis was put on an optimal acetabular version next to the correction of the lateral coverage. Additionally, a concomitant arthrotomy was performed in every hip to check impingement-free range of motion after reorientation and in 50 hips (56%) an additional offset correction was performed. Survivorship analyses according to Kaplan and Meier were carried out and the endpoint was defined as conversion to a total hip arthroplasty, progression of osteoarthritis, or a Merle d'Aubign score 14. Predictive factors for poor outcome were calculated using the Cox-regression analysis. The cumulative 10-year survivorship of Series A was significantly decreased (77%; 95%-confidence interval [CI] 72–82%) compared to Series B (86%; 95%-CI 82–89%, p=0.005). Hips with an aspherical head showed a significantly increased survivorship if a concomitant offset correction was performed intraoperatively (90% [95%-CI 86–94%] versus 77% [95%-CI 71–82%], p=0.003). Preoperative factors predicting poor outcome included a high age at surgery, a Merle d'Aubign score 14, a positive impingement test, a positive Trendelenburg sign, limp, an increased grade of osteoarthritis according to Tönnis, and (sub-) luxation of the femoral head (Severin > 3). In addition, predictive factors related to the three dimensional orientation of the acetabular fragment were identified. These included total, anterior, and posterior acetabular over-coverage or under-coverage, acetabular retroversion or excessive anteversion, a lateral center edge angle < 22 °, an acetabular index > 14 °, and no offset correction in aspherical femoral heads. A good long term result after PAO mainly depends on optimal three-dimensional orientation of the acetabulum and impingement-free range of motion with correction of an aspherical head neck junction if necessary

Background. The reported outcomes of unicompartmental knee replacement (UKR) for spontaneous osteonecrosis of the knee (SPONK) often derive from small series with an average followup of 5 years, enabling to generate meaningful conclusions. Therefore, we determined the long-term functional results and the 10-years survivorship of the implant in all patients with advanced SPONK of the medial tibio-femoral compartment treated with a unicompartmental knee arthroplasty at our institute. Methods. We retrospectively evaluated 84 consecutive patients with late stage SPONK. All patients received a pre-operative MRI to confirm the diagnosis, to exclude any metaphyseal involvement and to assess the absence of significative degenerative changes in the lateral and PF compartment. Mean age at surgery was 66 years and mean body mass index (BMI) was 28.9. In all cases, SPONK involved the medial compartment; in 77 cases the medial femoral condyle (MFC) was involved, while in 7 cases the pathology site was the medial tibial plateau (MTP). Radiological evaluation was conducted by 3 different radiologists and clinical evaluation according to KSS and WOMAC score was performed by 3 fellows from outside institutions, with no previous clinical contact with the patients, at a mean followup of 98 months. Results. We found a significant improvement in VAS score for residual pain self-assessment and maximum knee flexion (p<0.0001). The 10-year Kaplan-Meier survivorship with revision for any reason as endpoint was 89%. Mean results at final observation point for global KSS and WOMAC score were 87.1 (range 45–100; standard deviation 13.8) and 12 (range 0–44; standard deviation 10.3), respectively. No patient had significant radiographic signs of osteoarthritis progression in the lateral compartment or in the patello-femoral compartment at final evaluation. Conclusions. Our findings suggest that medial UKR performed for late stage SPONK of the medial tibio-femoral compartment in selected patients provides satisfactory long term clinical and radiographical results, with a 10-years Kaplan-Meier survivorship of the implant of 89%

Aims

The aims of this study were to determine the cumulative ten-year survivorship of hips treated for acetabular fractures using surgical hip dislocation and to identify factors predictive of an unfavourable outcome.