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OBJECTIVES: Treatment of pathologies of the central and peripheral compartment of the hip using arthroscopic assisted mini-open arthrotomy via the Smith-Petersen approach. INDICATIONS: Cam- and pincer-type femoroacetabular impingement (FAI), labral tear, loose bodies. (RELATIVE) CONTRAINDICATIONS: Osteoarthritis of the hip with Tönnis classification grade ≥ 2. SURGICAL TECHNIQUE: After mini-open approach to the hip joint via direct anterior muscular gap, the anterior capsule is split with protection of the labrum. Decompression allows the joint to be inspected using an arthroscope. Depending on the intra-articular findings, additional procedures can be performed (e.g., curettage of the cartilage, microfracturing, matrix-induced autologous chondrocyte implantation [MACI]). Cases with pincer-type FAI or labral tear can also be addressed. After partial release, the cam-type FAI can be resected using a surgical burr. POSTOPERATIVE MANAGEMENT: Partial weightbearing for 2-6 weeks with 10-20 kg or half body weight using crutches depending on the intraoperative treatment. RESULTS: Radiological analysis of the pre- and postoperative X­rays (n = 69) prove that this surgical technique is suitable to address pathologies especially FAI syndromes. The α­angle according to Nötzli could be reduced from a mean preoperative value of 72.8° to 49.4° postoperative. In combined cam-type and Pincer-type FAI syndrome (n = 16), the lateral center-edge angle could be reduced from a mean preoperative value of 50.2° to 37.6° postoperatively. The clinical follow-up (n = 29) revealed good midterm outcomes after arthroscopic assisted mini-open arthrotomy (modified Harris Hip Score [mHHS] 84.8 points after 4.9 years [range 4.2-5.7; ±0.43]).

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INTRODUCTION: Short femoral hip stems with a metaphyseal anchoring concept have been designed to treat younger patients with good bone quality. The aim of this study was to reconstruct the centre of rotation and soft tissue balancing and preserve bone in the long-term perspective. MATERIALS AND METHODS: Eighteen human femurs were randomised into three groups: (1) metaphyseal anchoring short stem, (2) shortened straight stem, (3) straight stem). Prior to the implantation of the hip stems, a computed tomography (CT) of the bones was performed and the femoral ante-torsion and ante-tilt was measured and compared to the results of the post-implantation CT. This could be calculated based on the 3D coordinates taken from the pre- and post-op CT scans, which were transformed into the same coordinate systems. RESULTS: The mean preoperative caput-collum-diaphyseal (CCD) angle for the three groups was 126.87° ± 3.50° (Group 3: 129.64° ± 3.53°, Group 1: 123.76° ± 5.56°, Group 2: 127.53° ± 1.42°) and was consistent with published reports. The postoperative CCD angles with 126.85° ± 3.43° were within a very good reconstruction range for all three groups. The anterior offset comparison among these three groups showed significant difference in reconstruction. The smallest difference between the anatomical (preoperative) and postoperative condition was seen in Group 1 (1.47° ± 0.60°), followed by Group 2 (3.60° ± 0.23°) and Group 3 (8.00° ± 0.70°) groups. The horizontal offset showed no significant difference among the groups and was within the window of ± 5 mm. CONCLUSION: In this cadaver study, we found that the metaphyseal anchoring, partially neck-preserving short hip stem best reconstructs the ante-torsion and the ante-tilt of the femoral neck. Therefore, it can be a useful stem in younger or active middle-aged patients.

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INTRODUCTION: The aim of this study was to determine number and type of failures and revisions after usage of a constrained tripolar acetabular liner in patients with high risk of dislocation. Potential correlations between these failures and the factors included were analyzed. MATERIALS AND METHODS: In this retrospective study 55 participants in 68 cases were included after treatment with constrained tripolar acetabular liner. Patient specific data as well as surgery and implant specific data were collected. Radiological images were assessed. Furthermore, the gluteal function was analyzed. The parameters were statistically verified with regard to their influence on the failure of the constrained tripolar liner. RESULTS: This study included 16 cases (in nine participants) of postoperative failure. This results in a survival rate of 76.5% regarding the number of cases after 17 months. The statistical analysis of the different parameters considered that the number of previous surgeries has a significant (p = 0.027) influence on the failure. CONCLUSIONS: This retrospective study shows that treatment with constrained tripolar acetabular liners is a satisfactory method of treatment in cases with a high risk of dislocation. However, in cases with an increasing number of previous surgeries, an increased risk of failure was found. Therefore, in such cases, this type of supply treatment should be treated critically.