Patient-specific instrumentation improved mechanical alignment, while early clinical outcome was comparable to conventional instrumentation in TKA.

PURPOSE: The aim of this prospective study was to compare early clinical outcome, radiological limb alignment, and three-dimensional (3D)-component positioning between conventional and computed tomography (CT)-based patient-specific instrumentation (PSI) in primary mobile-bearing total knee arthroplasty (TKA). METHODS: Two hundred ninety consecutive patients (300 knees) with severe, debilitating osteoarthritis scheduled for TKA were included in this study using either conventional instrumentation (CVI, n = 150) or PSI (n = 150). Patients were clinically assessed before and 2 years after surgery according to the Knee-Society-Score (KSS) and the visual-analog-scale for pain (VAS). Additionally, the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) and the Oxford-Knee-Score (OKS) were collected at follow-up. To evaluate accuracy of CVI and PSI, hip-knee-ankle angle (HKA) and 3D-component positioning were assessed on postoperative radiographs and CT. RESULTS: Data of 222 knees (CVI: n = 108, PSI: n = 114) were available for analysis after a mean follow-up of 28.6 ± 5.2 months. At the early follow-up, clinical outcome (KSS, VAS, WOMAC, OKS) was comparable between the two groups. Mean HKA-deviation from the targeted neutral mechanical axis (CVI: 2.2° ± 1.7°; PSI: 1.5° ± 1.4°; p < 0.001), rates of outliers (CVI: 22.2%; PSI: 9.6%; p = 0.016), and 3D-component positioning outliers were significantly lower in the PSI group. Non-outliers (HKA: 180° ± 3°) showed better clinical results than outliers at the 2-year follow-up. CONCLUSIONS: CT-based PSI compared with CVI improves accuracy of mechanical alignment restoration and 3D-component positioning in primary TKA. While clinical outcome was comparable between the two instrumentation groups at early follow-up, significantly inferior outcome was detected in the subgroup of HKA-outliers. LEVEL OF EVIDENCE: Prospective comparative study, Level II.

Arthroscopic management of massive rotator cuff tears: an evaluation of debridement, complete, and partial repair with and without force couple restoration.

PURPOSE: To evaluate the effectiveness of arthroscopic debridement (DB), partial (PR), and complete repair (CR) for massive rotator cuff tears (mRCT) in terms of functional and subjective parameters, and repair integrity. METHODS: For this single-centre study, 68 consecutive shoulders with mRCT involving at least three tendons and treated with arthroscopic DB (n = 23), PR (n = 22), and CR (n = 23) were included. All patients (52-81 years) were prospectively assessed before and at a mean of 45 months after surgery using functional and subjective parameters. Preoperative tendon rupture pattern and post-operative repair integrity were assessed by MRI. A coding system describing accurately rotator cuff rupture, treatment, and integrity was established. RESULTS: All treatment groups improved significantly from pre- to post-operative (P < 0.01), while preoperative parameters, except fatty degeneration, were not significantly different. However, post-operative comparisons revealed similar scores with DB (constant score, CS 65.8 ± 14.7, qDASH 24.1 ± 20.6) and PR (CS 67.5 ± 9.9, P = n.s.; qDASH 20.5 ± 14.4, P = n.s.), while CR were significantly better (CS 80.3 ± 8.9; qDASH 7.0 ± 8.7; P ≤ 0.001). Force couple restoration of PR did not significantly influence outcome. Re-tear rates with CR (29 %) were lower compared to PR (53 %). Intact CR compared to intact PR showed better CS (83.4 ± 7.3 vs. 68.5 ± 10.6, P = 0.009) and qDASH (5.4 ± 8.3 vs. 21.2 ± 9.5, P = 0.006). The vast majority of patients were satisfied with their arthroscopic procedure (DB 87 %; PR 86 %; CR 91 %). CONCLUSION: Arthroscopic DB, PR, and CR were effective in treating mRCT involving at least three tendons. Reparability of mRCT was influenced by fatty degeneration of the muscles. However, CR showed the most favourable short-term improvements. LEVEL OF EVIDENCE: IV.