Low prevalence of relevant associated articular lesions in patients with acute III-VI acromioclavicular joint injuries.

PURPOSE: To define the prevalence of associated articular injuries in patients with severe (Rockwood's III-VI) acute acromioclavicular joint injuries and to find out how many of these were associated with the traumatic event and required surgical treatment. METHODS: Retrospective observational multicentric study performed in ten centres included patients who required surgery for acute acromioclavicular joint injuries between 2010 and 2017. The inclusion criteria were: presence of an acute acromioclavicular joint injury (grades III-IV-V-VI) and surgical treatment within 3 weeks of injury that included a full arthroscopic evaluation of the shoulder. Basic epidemiological data, severity of the original injury, prelesional sport level and prelesional work site requirements were recorded. The presence of intraarticular glenohumeral lesions and information of their characteristics, treatment, and whether each lesion was considered acute or pre-existing was also recorded. RESULTS: Two-hundred one subjects [mean (SD) age 36.7 (11.7) years] with acute acromioclavicular joint injuries (110 Rockwood type III, 34 type IV, 56 type V and 1 type VI) fulfilled the inclusion criteria. A total of 28 (13.9%) associated articular lesions were found. These lesions were more often found in grade IV injuries (26.5% in grade IV vs 11.4% in grade III, p = 0.037) and presented in males (18.7% in males vs 4% in females, p = 0.015). Age, laterality, sport level or work requirements did not affect the prevalence of associated lesions. Twelve were rotator cuff tears (6 PASTA lesions, 3 partial supscapularis tears, 2 bursal supraspinatus tears and 1 full-thickness supraspinatus tear), 16 were labral tears (9 anterior, 1 posteroinferior and 6 SLAP). Only 14 (50% of lesions, 7% of total subjects) were considered acute and all but one (an SLAP type 2 tear) required further surgical attention. Most pre-existing lesions were left untreated (n = 7) or managed with minimal debridement (n = 6), and only two required further surgery. The prevalence of associated lesions that required surgical management was 7.46%. CONCLUSIONS: The prevalence of relevant associated lesions in subjects with acute grade III to VI ACJI is relatively low. Only 14% of subjects have an associated lesion and only half of these required further surgical attention. LEVEL OF EVIDENCE: Retrospective case series, level IV.

Biomechanical analysis of acromioclavicular joint dislocation repair using coracoclavicular suspension devices in two different configurations.

BACKGROUND: The best treatment option for some acromioclavicular (AC) joint dislocations is controversial. For this reason, the aim of this study was to evaluate the vertical biomechanical behavior of two techniques for the anatomic repair of coracoclavicular (CC) ligaments after an AC injury. MATERIALS AND METHODS: Eighteen human cadaveric shoulders in which repair using a coracoclavicular suspension device was initiated after injury to the acromioclavicular joint were included in the study. Three groups were formed; group I (n = 6): control; group II (n = 6): repair with a double tunnel in the clavicle and in the coracoid (with two CC suspension devices); group III (n = 6): repair in a "V" configuration with two tunnels in the clavicle and one in the coracoid (with one CC suspension device). The biomechanical study was performed with a universal testing machine (Electro Puls 3000, Instron, Boulder, MA, USA), with the clamping jaws set in a vertical position. The force required for acromioclavicular reconstruction system failure was analyzed for each cadaveric piece. RESULTS: Group I reached a maximum force to failure of 635.59 N (mean 444.0 N). The corresponding force was 939.37 N (mean 495.6 N) for group II and 533.11 N (mean 343.9 N) for group III. A comparison of the three groups did not find any significant difference despite the loss of resistance presented by group III. CONCLUSION: Anatomic repair of coracoclavicular ligaments with a double system (double tunnel in the clavicle and in the coracoid) permits vertical translation that is more like that of the acromioclavicular joint. Acromioclavicular repair in a "V" configuration does not seem to be biomechanically sufficient.