The Infinity-Lock System for Chronic Grade III AC Joint Dislocation: A Novel Technique, Rehabilitation Protocol and Short Term Results

Early to Mid-term Results of Coracoclavicular Ligament Reconstruction Using the Infinity-Lock Button System in the Management of Traumatic Acromioclavicular Joint Dislocations and Lateral End of Clavicle Fractures

Background The management of distal clavicle injuries with disruption of the coracoclavicular ligaments (CCLs) is challenging. The aim of this study was to assess the functional results of reconstructing the CCLs with the Infinity-Lock Button System using validated outcome measures, patient satisfaction scores, return to pre-injury activity, and complications. Methods A total of 28 cases of CCL disruption were assessed over a seven-year period, which included 14 lateral end-of-clavicle fractures and 14 acromioclavicular joint (ACJ) dislocations. All patients underwent stabilisation of the CCLs using the Infinity-Lock Button System. Patients were assessed preoperatively and postoperatively using validated outcome measures such as visual analogue scale (VAS), Oxford Shoulder Score (OSS), Quick Disabilities of Arm, Shoulder & Hand (Q-DASH) scores, return to pre-injury level of activities, patient satisfaction scores, and complications were reviewed. Results The mean age of patients was 36.7 years (18-74 years). The mean follow-up was 38.6 months (8-68 months). The mean time to surgery was 75.8 days (3-619 days). There was a statistically significant improvement in postoperative VAS, OSS, and Q-DASH scores compared to the preoperative (p-value <0.001). Out of the 28 participants, 23 (82.1%) returned to pre-injury level of activities, 25 (89.7%) reported 'good' or 'excellent' outcomes following the intervention, and none of the patients reported functional instability postoperatively. None of the patients required revision surgery or implant removal. Conclusion CCL reconstruction is vital in the management of clavicular injuries. This study demonstrates the safe use of the Infinity-Lock Button System in these injuries with statistically significant improvement in early patient-reported outcome measures, return to pre-injury level of activities, and subjective patient satisfaction.

Kinematic and Radiographic Evaluation of Acromioclavicular Reconstruction with a Synthetic Ligament

Purpose

The optimal surgical technique for unstable acromioclavicular (AC) and coracoclavicular (CC) joint injuries has not yet been established. The biomechanical and radiographic effect of the LockDown device, a synthetic ligament for AC joint reconstruction, was evaluated to assess the optimal surgical technique for unstable AC and CC joint injuries. It was hypothesized that the LockDown device would restore AC joint kinematics and radiographic stability to near native values.

Methods

Three fresh frozen cadaveric torsos (6 shoulders) modelled CC joint motion in their "native," "severed," and "reconstructed" states. The effects of stressed and unstressed native, severed, and reconstructed conditions on AC separation and CC distances in anteroposterior, mediolateral, and inferosuperior directions during shoulder abduction, flexion, and scaption were assessed. The analysis of variance (p, 0.05) was used to compare CC distance and peak AC distance in anteroposterior, mediolateral, and inferosuperior directions during shoulder flexion, abduction, and scaption measurements among native, severed, and reconstructed states with unstressed and stressed Zanca radiographic views.

Results

From radiographic analyses, the CC distance was significantly greater (p=0.001) across the surgical state in stressed versus unstressed views. Mean difference between stressed and unstressed views was 1.8 mm in native state, 4.1 mm in severed state, and 0.9 mm in reconstructed state. The CC distance was significantly greater in the "severed" state (10.4 mm unstressed; 14.5 mm stressed) compared to the "native" state (p=0.016) (6.5 mm unstressed; 8.3 mm stressed) and compared to the "reconstructed" state (p=0.005) (3.1 mm unstressed; 4.0 mm stressed) and significantly less (p=0.008) in the "reconstructed" state compared to the "native" state. CC distances decreased from native to reconstructed, an average of 3.3 mm for unstressed and 4.3 mm for stressed. On average, peak AC joint separation distance in anteroposterior, mediolateral, and inferosuperior directions during shoulder-abduction, flexion, and scaption was shown to be restored to 11.5 mm of native values after reconstruction with LockDown device.

Conclusion

Reconstruction of AC joint with LockDown synthetic ligament restores motion of clavicle and acromion to near native values, thereby decreasing scapular dyskinesis and enhancing AC joint stability.

Does Weaver-Dunn procedure have a role in chronic acromioclavicular dislocations? A meta-analysis

Background

In treatment of chronic acromioclavicular (AC) joint dislocations, both the Weaver–Dunn procedure (WD) and CC ligament reconstruction (CCR) are recommended options due to the low possibility of healing of the coracoclavicular (CC) ligaments. The aim of this review was to determine whether CCR will yield favorable clinical and radiographic outcomes in the treatment of chronic AC dislocations.

Method

The Cochrane Library, EMBASE, and PubMed databases were searched for literature on chronic AC dislocations from data inception to June 30, 2021. Patient data were pooled using standard meta-analytic approaches. The Cochrane-Mantel–Haenszel method and variance-weighted means were used to analyze the outcomes. The Review Manager version 5.3 software (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark) was used to calculate the heterogenicity, mean difference, and relative risk (RR) for all outcomes in the meta-analysis.

Results

The current analysis included four trials on this topic, and all AC joint dislocations were classified as Rockwood types III to VI. The pooled data showed that the CCR group had significantly better post-operative American Shoulder and Elbow Surgeons Shoulder (ASES) scores, Oxford Shoulder Scores (OSSs), and Nottingham Clavicle Scores (NCSs) than the WD group, with a significant difference (p < 0.001, p = 0.020, and p < 0.001, respectively). In terms of the post-operative Constant-Murley Scores (CMSs), there were no significant differences between the CCR group and the WD group (p = 0.100). The CCR group had significantly better post-operative abduction and flexion of the index shoulder than the WD group (p < 0.001 and p < 0.001, respectively). In terms of radiological outcomes, the post-operative coracoclavicular distance (CCD) with a 10 kg load was smaller in the CCR group compared to that in the WD group (p < 0.001). The overall surgical wound infection rate was 11.6% in the WD group and 12.9% in the CCR, respectively (p = 0.82).

Conclusion

The CCR group had better clinical outcome scores in the ASES, OOS, NCS, abduction, flexion, and external rotation than the WD group. In terms of radiological outcomes, the CCR group showed less displacement in weight-loaded post-CCD than the WD group, which indicated that the CCR provided more stability and resistance to deformation forces.

New Trends in Shoulder Surgery from Biomechanics to the Operating Room

After a rigorous peer review process, twelve papers were accepted and published [...].