Comparison between hook plate fixation with and without coracoclavicular ligament suture for acute acromioclavicular joint dislocations.

BACKGROUND: Hook plates are widely used for repair of acromioclavicular joint (ACJ) dislocations. However, it is unclear whether repair of torn coracoclavicular (CC) ligament is necessary. The purpose of this study was to evaluate the outcomes of the hook plate fixation with direct CC ligament repair for acute ACJ dislocation in comparison with the hook plate fixation without direct CC ligament repair. METHODS: The study included 120 patients with acute ACJ dislocations who underwent surgery. The patients were divided into 73 patient groups with Arbeitsgemeinschaft für Osteosynthesefragen (AO) hook plate fixation and direct CC ligament repair and 47 patient groups without direct CC ligament repair. For clinical assessments, the American Shoulder and Elbow Surgeons score, constant score, and time for implant removal were recorded. The corcoclavicular distance (CCD) and the CCD ratio were used for the evaluation of reduction. Typical reported complications, such as secondary dislocation, implant failure or loosening, peri-implant fracture, acromion osteolysis, and postoperative ACJ arthrosis, were also analyzed. RESULTS: There were no differences in the clinical outcomes between the two groups. There was no difference in the timing of implant removal between the two groups. The last follow-up CCD was not statistically significant between group with direct CC ligament repair and without repair (9.1 ± 3.3 vs. 9.0 ± 2.8, respectively, p > 0.05). The last follow-up CCD ratio showed significant differences between the two groups (12.6 ± 25.5% vs. 26.3 ± 39.7, respectively, p < 0.05). There was no statistically significant difference in the complication rate between the two groups. CONCLUSION: The hook plate fixation with direct CC ligament repair group was better for maintenance of reduction than that of the hook plate fixation without direct CC ligament repair group. Although, there were no differences of clinical outcomes and complications between two groups. LEVEL OF EVIDENCE: Level III, Retrospective Study.

Comparison of a novel hybrid hook locking plate fixation method with the conventional AO hook plate fixation method for Neer type V distal clavicle fractures.

BACKGROUND: The conventional AO hook locking compression plate (LCP) (Synthes, Solothurn, Switzerland) has only three holes for lateral fragments; therefore it is not suitable for use during the fixation of small-comminuted fragments in some cases. Recently, a novel hybrid hook LCP (TDM, Seoul, Korea) was developed to overcome this limitation. Here, we evaluated the clinical and radiologic outcomes of a novel hybrid hook LCP for Neer type V distal clavicle fractures compared to the outcomes of a conventional AO hook plate. METHODS: Seventy-eight consecutive patients who underwent hook LCP fixation for Neer type V distal clavicle fractures were included. The subjects were divided into 2 groups: the conventional AO hook LCP group and the novel hybrid hook LCP group. For clinical assessments, the American Shoulder and Elbow Surgeons (ASES) score, Korean shoulder score (KSS), and Constant score were recorded. The percentage modified coracoclavicular distance (MCCD %) was used for the evaluation of fracture reduction. Typical reported complications, such as secondary dislocation, implant failure or loosening, peri-implant fracture, acromion osteolysis, postoperative acromioclavicular joint arthrosis, non-union, or delayed union, were also analyzed. RESULTS: There were no differences in the clinical outcomes (ASES, KSS, and Constant scores) between the two groups. Bone union was achieved in a significantly shorter period in the hybrid hook LCP group (13.6±2.0weeks) than in the AO hook LCP group (17.5±4.8weeks, p<0.001). Consequently, the time to implant removal was also significantly shorter in the hybrid hook LCP group (4.0±0.5months) than in the AO hook LCP group (5.4±1.1months, p<0.001). The MCCD% showed no significant differences between the treatment groups. There was no statistically significant difference in the complication rate between the two groups; however, the hybrid hook LCP fixation resulted in a lower prevalence of hook-related complications. CONCLUSION: The hybrid hook LCP fixation showed satisfactory clinical and radiologic outcomes in comparison with the AO hook LCP fixation. The hybrid hook LCP is useful for multiple screw fixation of inferior comminuted fragments in Neer type V distal clavicle fractures. The bone union was significantly shorter; thus, the time to implant removal was also significantly shorter. LEVEL OF EVIDENCE: Level III, Retrospective study.

New predictors for subscapularis tear: Coraco-lesser tuberosity angle, lesser tuberosity angle, and lesser tuberosity height.

BACKGROUND: The pathogenesis of degenerative subscapularis (SC) tear is not clear, several mechanisms are involved: intrinsic tendon degeneration or subcoracoid impingement. The aim of this study was to propose new radiographic markers, the coraco-lesser tuberosity angle (CLA), lesser tuberosity angle (LTA) and lesser tuberosity height (LTH). The hypothesis was that higher values of CLA, LTA, and LTH would be associated with a higher likelihood in detecting a SC tear. METHOD: A total of 114 patients who classified as SC tears through arthroscopic evaluation were retrospectively enrolled in the study from 2016 to 2018. Fifty-seven patients with impingement syndrome were also enrolled as the control group for normal-population comparison. The CLA was measured on an anteroposterior shoulder x-ray image with the arm in neutral rotation, the LTA and LTH were measured on magnetic resonance imaging. Multivariable analyses were used to clarify the potential risks for SC tears. All measurements were calculated by two shoulder surgeons independently measured at 2 different times, 1 month apart. RESULTS: The intra- and inter-observer reliabilities for radiologic measurements and the interobserver reliability of SC tear classification were almost perfect. The mean CLA value of SC tear group (41.4±4.2°) was significantly larger than that of the control group (38.7±4.0°, p<0.001). The mean LTA value of SC tear group (33.4±4.3°) was significantly larger than that of the control group (31.0±3.9°, p=0.001). Mean LTH value was 9.5±1.9mm in patients and 8.9±1.5mm for controls, there was no statistically significant difference (p=0.054). Multivariable analysis showed that larger CLAs significantly increased the risk of SC tears, with odds ratios of 1.17 per degree. Moreover, larger LTAs also significantly increased the risk of SC tears, with odds ratios of 1.14 per degree. CONCLUSION: Our findings confirmed associations between new predictors (CLA and LTA) and SC tears. CLA and LTA values were greater in patients with SC tears than in controls, suggesting that they may be independent risk factors for SC tear onset. LEVEL OF EVIDENCE: IV, retrospective study.

The supraspinatus occupation ratios of both the ≥ 50% articular- and bursal-side partial-thickness rotator cuff tears were low and the infraspinatus occupation ratio of the ≥ 50% bursal-side partial-thickness rotator cuff tears was low.

PURPOSE: The purpose of this study was to analyze the relationship between the occupation ratio and partial-thickness rotator cuff tears. METHODS: The study included and retrospectively investigated 683 patients with partial-thickness rotator cuff tears between 2013 and 2017. Fifty patients with impingement syndrome were also enrolled as the control group for normal-population comparison. The participants were divided into five groups: Group A, control group; Group B, < 50% articular-side tears; Group C, ≥ 50% articular-side tears; Group D, < 50% bursal-side tears; and Group E, ≥ 50% bursal-side tears. Muscle volume was evaluated by measurement of each occupation ratio of the supraspinatus and infraspinatus tendons on the most lateral view of the T1-weighted oblique-sagittal images in which the scapular spine remained in contact with the scapular body. RESULTS: Fifty patients were enrolled in Group A. A total of 683 patients with Partial thickness rotator cuff tear were divided and classified into the following groups: 272 into Group B, 153 into Group C, 161 into Group D, and 97 into Group E. The supraspinatus occupation ratios of all partial-thickness rotator cuff tear groups were significantly lower than those of the control group. Furthermore, the supraspinatus occupation ratios of Groups C and E (≥ 50% partial-thickness rotator cuff tears) were significantly lower than those of Groups B and D (< 50% partial-thickness rotator cuff tears). However, the infraspinatus occupation ratio of only Group E was significantly lower than that of the other groups. CONCLUSION: The supraspinatus occupation ratios of both the ≥ 50% articular- and bursal-side partial-thickness rotator cuff tears were lower than those of the other partial-thickness rotator cuff tears. Conversely, the infraspinatus occupation ratio of only the ≥ 50% bursal-side partial-thickness rotator cuff tears was low. LEVEL OF EVIDENCE: IV.