Faster strength recovery and better strength ratio with arthroscopic Latarjet compared to the open technique: An observational study.

INTRODUCTION: The arthroscopic bone block has shown reliability and reproducibility regarding functional scores and shoulder mobility compared to the open bone block technique. The recovery of muscle strength, especially the strength ratio external rotator/internal rotator (ER/IR), is crucial to recovering satisfactory function. This ratio should be as near to 1 as possible, meaning a good strength balance. Little is known about the difference in strength recovery between the open and arthroscopic techniques. HYPOTHESIS: Arthroscopic Latarjet reduces surgical stress and improves the strength recovery and strength ratio. OBJECTIVES: To compare arthroscopic and open Latarjet procedures for shoulder muscle strength and functional outcomes. MATERIAL AND METHODS: It was an observational longitudinal and prospective cohort follow-up. Two groups of patients were accessible for comparison: 35 in an arthroscopy group and 38 in an open group. The main outcome was the muscle strength of shoulder muscles measured with a dynamometer and expressed in Newton (N) at day 21 (D21), D45, D90, D180, and D365 in the operated and contralateral shoulders. The measurements were made for the pectoralis major, the three deltoid fascicles, and the subscapularis. The shoulder ER/IR strength ratio was calculated. Other variables were the range of motion (ROM), the Walch-Duplay (WD), the Western Ontario Shoulder Instability score (WOSI), and the Visual Analogic Scale for pain assessment. The strength, ROM, and functional scores were compared between open and arthroscopy with linear mixed models. RESULTS: The median strengths at 52 weeks were significantly higher than at 3 weeks (P<10-4): anterior deltoid (AD) 8N (Q1:7, Q3: 9) versus 4N (Q1:2, Q3: 5), lateral deltoid (LD) 9N (Q1:9, Q3: 11) versus 6N (Q1:4, Q3: 7), posterior deltoid (PD) 14N (Q1:12, Q3: 15) versus 9N (Q1:8, Q3: 10), subscapularis 10N (Q1:9, Q3: 12) versus 7N (Q1:5, Q3: 8), and pectoralis major (PM) 11N (Q1:9, Q3: 12) versus 7N (Q1:5, Q3: 10). The overall strengths were lower in the open group compared to the arthroscopy group: AD -2.1N (CI95%[-3.1--1.2], p=0.0005), LD -1.3N (CI95% [-2.4--0.15], p=0.03), PD -0.35N (CI95% [-1-0.9], p=0.52), subscapularis -2.1N (CI95% [-3.3--0.7], p=0.006), and PM -1.4N (CI95% [-2.2--0.02], p=0.03). The ER/IR ratio was stable throughout the follow-up for both the operated and contralateral shoulders (p>0.5). The overall mean ratio was 1.3 (median 1.2, Q1: 1, Q3:1.45) for the operated shoulder and 1.1 (median 1, Q1: 0.9, Q3:1.3) for the contralateral shoulder (p=0.0004). The average ER/IR ratio was 0.27 points higher in the open group (CI95% [0.1-0.46], p=0.003). The ROM was similar between the two groups, and there was no correlation between the ER/IR ratio and the ROM (p>0.5). The VAS < 3 weeks and WD > 12 weeks were significantly poorer in the open group: +0.61 (CI95% [0.03-1.16] p=0.02), and -7.3 points (CI95% [-13--0.01], p=0.05), on average, respectively. CONCLUSION: The patients in the arthroscopy group had a better ER/IR strength ratio (closer to 1) and better WOSI after 12 weeks. The strength and the ROM were not correlated with each other. LEVEL OF EVIDENCE: III.

Arthroscopic Latarjet procedure and suture-button fixation: can we predict nonunion early?

BACKGROUND: The arthroscopic Latarjet procedure is a technically challenging technique that provides well-known results. The first series reported fixation with screws. An alternative fixation technique has been proposed, using a button, to improve the reproducibility and to decrease the complications due to screws. The first reports using this fixation technique have yielded comparable rates of fusion. The objective of this study was to assess the fusion rate and bone modifications with this type of fixation. METHODS: Two hundred sixteen patients were included in this prospective study. An arthroscopic Latarjet procedure, fixed with 1 button according to the Smith & Nephew technique, was performed by a single surgeon for the treatment of anterior instability. The radiographic protocol consisted of computed tomography scans at 3, 12, and 24 weeks postoperatively. We measured the coronal and sagittal positions of the bone block, distance between the bone block and the glenoid, diameter of the glenoid tunnel, fusion rate, and time to fusion. RESULTS: The position was deemed flush in 92.6% of cases in the coronal plane and under the equator in 87.5% of cases in the sagittal plane. At last follow-up, we observed 9 cases of nonunion (4%), as well as 18 cases of delayed fusion. The fusion rate was 92% at 3 months and 96% at 6 months. For bone blocks that ultimately healed, the diameter of the glenoid tunnel was <2 mm in 62% of cases at 3 weeks and <1 mm in 90% of cases at 3 months. Conversely, the diameter of this tunnel significantly increased and was >3 mm in all cases of delayed union or nonunion. CONCLUSION: The described technique achieved a reliable position of the bone block and a very good fusion rate with a new type of fixation. The time to obtain fusion can be lengthy, occurring between the third and sixth months. The diameter of the glenoid tunnel was the best predictive factor for fusion. Widening of the glenoid tunnel diameter >3 mm during the first 3 weeks was the most predictive factor for delayed union or nonunion of the bone block. This finding is probably explained by a sliding effect of the sutures through this tunnel, comparable to the bungee effect in anterior cruciate ligament repair in the knee.