Acromioclavicular joint dislocation Rockwood type III and V show no difference in functional outcome and 91% recovered well without the need for surgery.

PURPOSE: Acromioclavicular (AC) joint dislocations are common injuries, but the indication for and timing of surgery is debated. The objective of the study was to evaluate the results after acute AC joint dislocations Rockwood type III and V treated nonsurgically with the option of delayed surgical intervention. METHODS: This is a prospective cohort study with clinical, radiological and patient-reported outcome assessment at baseline, 6 weeks, 3 months, 6 months and 1 year after acute AC joint dislocation. Patients aged 18-60 with acute AC joint dislocation and a baseline panorama (Zanca) radiograph with an increase in the coracoclavicular distance of >25% compared to the uninjured side were eligible for inclusion. All patients were treated nonsurgically with 3 months of home-based training and with the option of delayed surgical intervention. The primary outcome was the Western Ontario Shoulder Instability Index (WOSI). Secondary outcomes were surgery yes/no and the Shoulder Pain and Disability Index (SPADI). RESULTS: Ninety-five patients were included. Fifty-seven patients were Rockwood type III and 38 patients were type V. There were no statistically significant differences in WOSI and SPADI between patients with type III and V injuries at any time point. Nine patients (9.5%) were referred for surgery; seven type III and two type V (ns). CONCLUSION: Ninety-one percent of patients with acute AC joint dislocation Rockwood type III and V recovered without surgery and there were no differences in outcome scores between type III and V at any time point. LEVEL OF EVIDENCE: Level IV.

The ISAKOS subclassification of Rockwood type III AC joint dislocations in a stable type A and an unstable type B is not clinically relevant.

PURPOSE: The treatment of Rockwood type III AC joint dislocations has been debated for decades. In 2014, the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) Upper Extremity Committee suggested a subclassification of the injury into type A, considered stable and best treated nonsurgically, and type B, considered unstable and best treated surgically. Type B is defined by the presence of scapular dyskinesis and overriding of the clavicle to the acromion on a modified lateral radiograph. The objective of the study was to investigate if this subclassification is clinically relevant. METHODS: This was a prospective cohort study. Inclusion criteria were patients aged 18-60 years with acute AC joint dislocation and a baseline Zanca radiograph with an increase in the CC distance of >25% compared to the uninjured side. All patients were treated nonsurgically with 3 months of home-based training and with the option of delayed surgical intervention. Patients were assessed at baseline and at follow-ups 6 weeks, 3 months, 6 months and 1 year after the injury. At the 6-week follow-up, patients were graded as stable and unstable according to the ISAKOS criteria. Outcomes were the Western Ontario Shoulder Instability Index (WOSI) and referral for surgery. RESULTS: At 6 weeks of follow-up, 20 patients were classified as stable type A and 69 were classified as unstable type B. The ISAKOS subclassification was not clinically relevant, but patients graded as stable had statistically significantly better WOSI scores at 6 months compared to the unstable group (p = 0.03) but not at 3 months or 1 year. Nine patients (9.5%), all from the unstable group, were referred for surgery. No patients from the stable group underwent surgery (n.s). CONCLUSION: The ISAKOS subclassification of Rockwood type III in a stable type A and an unstable type B is not clinically applicable. LEVEL OF EVIDENCE: Level II.

Patient-reported, clinical and radiological factors associated with the result after non-surgical management of acute AC joint dislocation Rockwood type III and V.

PURPOSE: The treatment of Rockwood type III and V acromioclavicular (AC) joint dislocations is controversial, and an individualized treatment algorithm is yet to be developed. The objective of this study was to investigate the association of demographical, clinical, patient-reported and radiological variables with the Western Ontario Shoulder Instability Index (WOSI) score and risk of surgery. METHODS: Inclusion criteria for this prospective cohort study were patients aged 18-60 with an acute AC joint dislocation with >25% increase in the coracoclavicular distance on bilateral Zanca radiographs. Patients were treated non-surgically with 3 months of home-based training and the option of delayed surgical intervention. The outcomes were the WOSI score and surgery yes/no. Demographical, clinical, patient-reported (WOSI and Shoulder Pain and Disability Index [SPADI]) and radiological variables were collected at baseline and 6 weeks after the injury and investigated for association with the outcomes at 3 months, 6 months and 1 year. RESULTS: Ninety-five patients with Rockwood type III/V AC joint dislocation were included. Pre-injury participation in overhead/collision sports was a risk factor for surgery with an odds ratio of 5 (p = 0.03). Reduced range of motion (ROM) at baseline was associated with reduced WOSI scores and increased risk of surgery. At 6 weeks, reduced ROM, increased SPADI and increased pain during cross-over were associated with the outcomes. Radiological measurements were not correlated with the result. At the 6 weeks follow-up, patients eventually requiring surgery could be detected with a sensitivity of 100% and a specificity of 94% based on a SPADI score of >30 and a ROM ≤ 140° in shoulder flexion or abduction. CONCLUSION: ROM was the only variable consistently associated with both WOSI and risk of surgery. Six weeks after the injury, it was possible to detect patients in need of surgery based on ROM and SPADI with a sensitivity of 100% and a specificity of 94%. LEVEL OF EVIDENCE: Level II.

Comparative study of two different horizontal stabilisation methods in arthroscopically assisted coracoclavicular stabilisation for acute acromioclavicular joint dislocations-Good clinical outcome and no correlation to recurrent anteroposterior instability.

PURPOSE: The hypothesis of this study was that acromioclavicular K-wire transfixation is noninferior to horizontal FiberTape cerclage in terms of vertical and horizontal stability in the short follow-up period of acute acromioclavicular joint (ACJ) dislocations fixed with an arthroscopically assisted coracoclavicular single bundle endobutton cerclage system. The secondary aim was to investigate the impact of postoperative recurrent instability on clinical outcomes in these populations. METHODS: In this consecutive clinical trial, all patients who underwent surgery for acute AC joint dislocation between January 2017 and December 2021 were included. Two groups were formed according to the additional AC stabilisation technique (K-wire group, cerclage group). Clinical examination and bilateral radiologic analysis (Zanca stress view, Alexander view) were performed with a follow-up period of at least 12 months. Satisfaction, return to sports, active range of motion, global shoulder scores and specific shoulder scores including constant score, disabilities of the arm, shoulder and hand (DASH) score and ACJ instability score (ACJI) were evaluated. Complications, including recurrent instability, and revision rate were assessed. RESULTS: Included were 59 patients (32 K-wire group, 27 cerclage group, 92% male, median follow-up 33 months). No significant differences were found in the clinical outcome parameters between the different techniques, except for the DASH value (superior in the K-wire group). Recurrent anteroposterior instability was radiographically detected in 27% of patients. No correlation was found between anteroposterior instability and clinical outcome parameters. There was no revision surgery due to chronic ACJ instability. CONCLUSION: Horizontal ACJ stabilisation with temporary K-wire transfixation does not appear to be inferior to a FiberTape cerclage technique in acute ACJ dislocations stabilised in an arthroscopically assisted single bundle DogBone technique. Recurrent ACJ instability detected radiographically does not necessarily correlate with the functional outcome and can be well compensated. LEVEL OF EVIDENCE: Level III.

The deltotrapezial fascia stabilizes the AC-Joint and its reconstruction restores the horizontal stability in AC-joint separations-a biomechanical comparison.

BACKGROUND: Various techniques are available for the reconstruction of acromioclavicular joint (ACJ) dislocations, with the main focus being on restoration of the AC capsule or coracoclavicular (CC) ligaments. Recent research has underlined the significance of the deltotrapezial fascia (DTF) and related muscles as dynamic stabilizers of the ACJ. HYPOTHESIS: Reconstruction of the DTF increases the stability of the ACJ in the horizontal plane more than a complete transection of the fascia, while not restoring the stability of the native state. METHODS: Five pairs of human cadaveric shoulders including the torsos were included in the study and underwent cyclic anterior-posterior loading using an electromechanical testing machine. The shoulders were put into three groups: group N (n = 10): native ACJ; group T (n = 10): ACJ with transected DTF; group R (n = 10): ACJ with reconstruction of the DTF after transection. The dislocation was recorded with an 3D optical measuring system. RESULTS: Group N showed a mean horizontal displacement of 2.94 mm (± 1.26), group T showed a mean anterior displacement of 3.33 mm (± 1.37) and group R showed a mean anterior displacement of 2.95 mm (± 1.08). The mean anterior displacement for group T was significantly higher after every measured number of cycles compared with groups N and R. There was no significant difference in mean anterior displacement between groups N and R. CONCLUSION: The transection of the DTF results in significantly reduced stability in the horizontal plane of the ACJ. A reconstruction of the DTF restores the stability of the native ACJ in the horizontal plane. Further clinical and biomechanical investigations should focus on reconstruction techniques of the DTF.

Mid-term clinical and sonographic outcomes of minimally invasive acromioclavicular joint reconstruction: mini-open versus arthroscopically assisted.

INTRODUCTION: The current literature describes various operative stabilization strategies which achieve good clinical outcomes after acute acromioclavicular joint (ACJ) dislocation. The aim of this study was to compare the mid-term clinical and sonographic treatment outcomes after minimally invasive mini-open and arthroscopic reconstruction. MATERIALS AND METHODS: We conducted a retrospective two-center study of patients with acute ACJ dislocation. Surgical treatment was performed using either a mini-open approach (MIOP) or an arthroscopic technique (AR). The primary outcome parameters of this study were the sonographically measured acromioclavicular (ACD) and coracoclavicular distances (CCD). Secondary outcome parameters included the Constant-Murley score (CS), range of motion (ROM), postoperative pain scale (VAS), return to daily routine, return to sports, complications, as well as operative revisions. RESULTS: After a mean follow-up of 29 months, 30 patients were included in this study with an average age of 41.3 ± 14.8 years (MIOP) and 41.2 ± 15.4 years (AR). The sonographic ACD (MIOP 9.11 mm vs. AR 8.93 mm, p = 0.41) and CCD (MIOP 25.08 mm vs. AR 24.36 mm, p = 0.29) distances showed no statistically significant differences. Furthermore, there was no statistically significant difference when compared to the contralateral side (p = 0.42). With both techniques, patients achieved excellent clinical outcome parameters without statistically significant differences in CS (MIOP 95 vs. AR 97, p = 0.11) and VAS (MIOP 1.76 vs. AR 1.14, p = 0.18). The return to daily activity and return to sport rates did not differ. There were neither complications nor revisions in both groups. CONCLUSION: Both minimally invasive techniques for acute ACJ stabilization achieved excellent clinical and sonographic outcomes without one technique being statistically superior to the other.

3D C-arm navigated acromioclavicular joint stabilization.

INTRODUCTION: Surgical treatment options for acromioclavicular joint separations are varied. Frequently, suspension devices (SD) are inserted for stabilization under arthroscopic view. This study investigates the feasibility and accuracy of three-dimensional (3D) digital-volume-tomography (DVT) C-arm navigated implantation with regard to the general trend toward increasingly minimally invasive procedures. MATERIALS AND METHODS: The implantation of a TightRope® suture button system (SD) via a navigated vertical drill channel through the clavicle and coracoid was investigated in 10 synthetic shoulder models with a mobile isocentric C-arm image intensifier setup in the usual parasagittal position. Thereby, in addition the placement of an additive horizontal suture cerclage via a navigated drill channel through the acromion was assessed. RESULTS: All vertical drill channels in the Coracoclavicular (CC) direction could be placed in a line centrally through the clavicle and the coracoid base. The horizontal drill channels in the Acromioclavicular (AC) direction ran strictly in the acromion, without affecting the AC joint or lateral clavicle. All SD could be well inserted and anchored. After tensioning and knotting of the system, the application of the horizontal AC cerclage was easily possible. The image quality was good and all relevant structures could be assessed well. CONCLUSION: Intraoperative 3D DVT imaging of the shoulder joint using a mobile isocentric C-arm in the usual parasagittal position to the patient is possible. Likewise, DVT navigated SD implantation at the AC joint in CC and AC direction on a synthetic shoulder model. By combining both methods, the application in vivo could be possible. Further clinical studies on feasibility and comparison with established methods should be performed.

Operative vs. conservative treatment of AC-Joint Dislocations Rockwood grade ≥ III -An economical and clinical evaluation.

INTRODUCTION: Acromioclavicular joint dislocations (ACD) are one of the most common shoulder injuries. There is no consensus in how to treat higher graded ACD ≥ Rockwood grade III. This study compares operative versus conservative treatment regarding costs and clinical outcome parameters. MATERIALS AND METHODS: This retrospective, consecutive case-control-study includes 14 patients. Seven operatively treated patients were matched, by Rockwood grade, with seven conservatively treated patients. The cost was extracted out of the clinical- and insurance-based cost sheets and furthermore these include the loss of earnings. Clinical examination, demographic data as well as different outcome-questionnaires were recorded. RESULTS: There were no significant differences between operative and conservative treated patients for outcome Questionnaires. Of note, there was a significantly higher incidence of tenderness over the AC-joint (p = 0.0038) postoperatively. As expected, economical evaluation showed various findings in favor of the conservative treatment. The costs for medical services (11012.39vs.1163.81USD; p = 0.0061), days of hospitalization (3.3vs.0days; p < 0.0001); total cost for medical treatment (30262.17 vs. 7833.82 USD; p = 0.0358) were significantly higher in the operative group. CONCLUSION: Even with a limited case number and a retrospective study design almost all clinical results were equal in both groups. Operative therapy of higher graded ACDs (Rockwood > III) compared to conservative is economically inefficient. Under consideration of clinical comparable results, indications for operative treatment should be set very carefully.

Superior clinical results for early arthroscopic treatment of grade IIIb and V acromioclavicular joint instability compared to delayed operative treatment.

BACKGROUND: Arthroscopy-assisted cortical fixation devices have been increasingly used in the operative management of both acute and chronic cases of acromioclavicular joint instability (ACJI). It has been hypothesized that delayed surgical management leads to inferior clinical and radiologic outcomes compared to acute treatment. The purpose of this study is to compare clinical and radiologic outcomes, scapula dyskinesia, and failure or revision rates of arthroscopically treated acute and chronic ACJI. METHODS: This retrospective study of prospectively collected data included all surgically treated patients with grade IIIb and V chronic ACJI between 2013 and 2017, matched 1:1 to a group of acute grade IIIb and V ACJI patients treated during the same time period. Chronic ACJI was defined as delayed surgical treatment >21 days after injury. Chronic cases received an additional hamstring autograft next to the suture pulley systems. Follow-up was obtained at an average of 3.2 years (range: 1.4-6.2). Clinical outcome scores included the Constant-Murley Score (CMS), Taft Score (TF), Nottingham Clavicle Score (NCS), ACJI Score, Sick Scapula Score (SSS), Subjective Shoulder Value (SSV), Subjective Shoulder Test (SST), American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) score, and the visual analog scale pain score. Radiologic follow-up was obtained pre- and postoperatively and at final follow-up. The 2-year results were compared to the results of a 1:1 matched-pair group comprising patients who were treated with an acute ACJI during the same period. RESULTS: Thirty-three (80.5%) of 41 chronic ACJI cases were available for follow-up and were compared with 33 matched-pair cases of acute ACJI (of 41). The clinical scores were significantly better in the acute cohort for the CMS (92 ± 8 vs. 88 ± 8, P = .030), ASES (91 ± 13 vs. 85 ± 13, P = .002), SSS (1.4 ± 1.6 vs. 3.4 ± 2.5, P = .0004), NCS (86 ± 13 vs. 81 ± 13, P = .049), TF (9.9 ± 1.9 vs. 9.0 ± 2.1, P = .030), and ACJI (83 ± 13 vs. 75 ± 1, P = .003). In contrast to the chronic cohort, the acute cohort illustrated a significant loss of reduction at follow-up (P = .020). CONCLUSION: Based on the results of this study, early arthroscopy-assisted operative treatment of grade IIIb and V ACJIs seems superior to delayed surgical intervention of grade IIIb and V ACJIs. Furthermore, an additional autograft loop leads to less loss of reduction compared with suture pulley/suspensory loop fixation standalones.

Complications after operative treatment of high-grade acromioclavicular injuries.

BACKGROUND: Treatment of Rockwood type III-V acromioclavicular (AC) joint injuries remains controversial. Numerous reconstruction techniques have been proposed. The purpose of this study was to describe the complication profile in a large cohort of patients who underwent surgical management of AC joint separations using a variety of reconstruction strategies. METHODS: All patients who underwent surgery for AC joint injuries from 2013 to 2019 at a single institution were identified. Chart review was performed to capture patient demographics, radiographic measurements, operative techniques, postoperative complications, and revision surgery. Structural failure was defined as a radiographic loss of reduction of greater than 50% when comparing immediate and final postoperative imaging. Logistic regression analysis was performed to identify risk factors for complications and revision surgery. RESULTS: Of the 279 patients included in the study, 66 (24%) had type III separations, 20 (7%) type IV, and 193 (69%) type V. Fifty-three percent underwent surgery acutely (<6 weeks of injury), and 40% were chronic (>3 months). A total of 252 of the 279 surgeries (90%) were performed open and 27 (10%) were arthroscopically assisted. Allograft was used in 164 of 279 (59%) cases. Specific operative techniques (with or without allograft) included hook plating (1%), modified Weaver Dunn (16%), cortical button fixation (18%), and suture fixation (65%). At mean 28-week follow-up, 108 complications were identified in 97 patients (35%). Complications were identified at mean 20 ± 21 weeks. Sixty-nine structural failures (25%) were identified. Persistent AC joint pain requiring injection, clavicle fracture, adhesive capsulitis, and hardware complications were the other most common complications. Twenty-one patients (8%) underwent unplanned revision surgery at mean 38 ± 28 weeks after the index procedure, with the most common indication for structural failure, hardware complications, or fracture of the clavicle or coracoid. Patients who had surgery after 6 weeks from injury had a significantly greater risk of having a complication (odds ratio [OR] 3.19, 95% confidence interval [CI] 1.34-7.77, P = .009) and a significantly greater risk of having structural failure (OR 2.65, 95% CI 1.38-5.28, P = .004). Patients who had an arthroscopic technique had a greater risk of structural failure (P = .002). Complications, structural failure, and revision surgery were not significantly correlated with use of allograft or specific operative techniques. CONCLUSION: Surgical management of AC joint injuries is associated with a relatively high complication profile. Loss of reduction in the postoperative period is common. However, the revision surgery rate is low. These findings are important for patient preoperative counseling.

Iatrogenic instability of the acromioclavicular joint leads to ongoing impairment of shoulder function even following secondary surgical stabilization.

PURPOSE: Iatrogenic instability of the acromioclavicular joint (ACJ) following distal clavicle excision (DCE) represents an infrequent pathology. Revision surgery to restore ACJ stability and alleviate concomitant pain is challenging due to altered anatomic relationships. The purpose of this study was to evaluate the used salvage techniques and postoperative functional and radiological outcomes in retrospectively identify patients with a painful ACJ following DCE. We hypothesized that iatrogenic instability leads to ongoing impairment of shoulder function despite secondary surgical stabilization. METHODS: 9 patients with a painful ACJ after DCE (6 men, 3 women, 43.3 ± 9.4 years) were followed up at a minimum of 36 months after revision surgery. Besides range of motion (ROM), strength and function were evaluated with validated evaluation tools including the Constant score and the DASH score (Disability of the Arm, Shoulder and Hand questionnaire), specific AC Score (SACS), Nottingham Clavicle Score (NCS), Taft score and Acromioclavicular Joint Instability Score (AJI). Additionally, postoperative X-rays were compared to the unaffected side, measuring the coracoclavicular (CC) and acromioclavicular (AC) distance. RESULTS: At follow-up survey (55.8 ± 18.8 months) all patients but one demonstrated clinical ACJ stability after arthroscopically assisted anatomical ACJ reconstruction with an autologous hamstring graft. Reconstruction techniques were dependent on the direction of instability. The functional results demonstrated moderate shoulder and ACJ scores with a Constant Score of 77.3 ± 15.4, DASH-score of 51.2 ± 23.4, SACS 32.6 ± 23.8, NCS 77.8 ± 14.2, AJI 75 ± 14.7 points and Taft Score 7.6 ± 3.4 points. All patients stated they would undergo the revision surgery again. Mean postoperative CC-distance (8.3 ± 2.8 mm) did not differ significantly from the contralateral side (8.5 ± 1.6 mm) (p > 0,05). However, the mean AC distance was significantly greater with 16.5 ± 5.8 mm compared to the contralateral side (3.5 ± 1.9 mm) (p = 0.012). CONCLUSION: Symptomatic iatrogenic ACJ instability following DCE is rare. Arthroscopically assisted revision surgery with an autologous hamstring graft improved ACJ stability in eight out of nine cases (88.9%). However, the functional scores showed ongoing impairment of shoulder function and a relatively high overall complication rate (33.3%). Therefore, this study underlines the importance of precise preoperative indication and planning and, especially, the preservation of ACJ stability when performing AC joint resection procedures. LEVEL OF EVIDENCE: Case series, LEVEL IV.

Bone tunnel placement influences shear stresses at the coracoid process after coracoclavicular ligament reconstruction: a finite element study and radiological analysis.

INTRODUCTION: Coracoid fractures after arthroscopic treatment of acromioclavicular (AC) joint separations lead to poor clinical outcomes. In this study, different configurations of bone tunnels in the lateral clavicle and coracoid were examined concerning the amount of stress induced in the coracoid. METHODS: An authentic 3D finite element model of an ac joint was established. Three 2.4 mm bone tunnels were inserted in the lateral clavicle, which were situated above, medially and laterally of the coracoid. Then, two 2.4 mm bone tunnels were inserted in the latter, each simulating a proximal and a distal suture button position. Von Mises stress analyses were performed to evaluate the amount of stress caused in the coracoid process by the different configurations. Then, a clinical series of radiographs was examined, the placement of the clavicle drill hole was analyzed and the number of dangerous configurations was recorded. RESULTS: The safest configuration was a proximal tunnel in the coracoid combined with a lateral bone tunnel in the clavicle, leading to an oblique traction at the coracoid. A distal bone tunnel in the coracoid and perpendicular traction as well as a proximal tunnel in the coracoid with medial traction caused the highest stresses. Anatomical placement of the clavicle drill hole does lead to configurations with smaller stresses. CONCLUSION: The bone tunnel placement with the smallest amount of shear stresses was found when the traction of the suture button was directed slightly lateral, towards the AC joint. Anatomical placement of the clavicle drill hole alone was not sufficient in preventing dangerous configurations. LEVEL OF EVIDENCE: Controlled laboratory study.

Mini-open vs. arthroscopic double tight-rope reconstruction after acute AC-joint dislocation: a comparison in functional outcome and sports activity.

INTRODUCTION: In athletes, acromioclavicular joint disruptions account for up to 50% of all shoulder injuries. In high-grade injuries, surgery is favored to ensure a correct restoration of the joint, especially in young athletes. The aim of this study was to compare the clinical, radiological and sport related outcomes of the arthroscopic stabilization with the fixation of the AC joint in a mini-open approach. MATERIALS AND METHODS: 19 patients treated arthroscopically (ASK) and 26 patients with an acute AC-joint dislocation Rockwood V who had undergone the mini-open (MO) surgery were included. Constant Murley Score (CMS), Taft Score (TS) and the Simple Shoulder Tests (SST) were evaluated. The sports activity level was determined according to Valderrabano and the athlete's recovery of their athletic activity level after surgery according to Rhee. Furthermore, all available X-ray images were analyzed. RESULTS: Patients in the ASK group achieved an average score of 11.7 ± 0.6 points in the SST, 10.3 ± 1.8 points in the TS and 91.2 ± 11.8 points in the CMS. On average, patients in the MO group achieved results of 10.5 ± 1.4 points in the SST, 11.7 ± 0.7 points in the TS and 91.6 ± 9.8 points in the CMS. The ASK group showed significant difference regarding the CC distance in side comparison (Δ = 3.6 mm), whereas no significant difference was found in the MO group (Δ = 0.8 mm). In comparison of both groups, the posterior as well as the combined translation were significantly greater in the ASK group than in the MO group (posterior: ASK: 24.8 mm, MO: 19.3 mm, combined: ASK: 29.1 mm, MO: 20.9 mm). Residual horizontal instability was greater in the ASK group (43%) than in the MO group (32%). Similar results were achieved in sports activity and the recovery of athletic activity (Valderrabano: ASK: 2.8, MO: 2.6; Rhee: ASK: 1.6, MO: 1.5). CONCLUSIONS: Both techniques prove to be effective for the stabilization of high-grade AC-joint disruptions in athletes and showed excellent clinical results. From a radiographic standpoint, the mini-open procedure appears superior to the arthroscopic technique. After mini-open surgery postoperative loss of correction is less common and greater horizontal stability is achieved. The results also suggest the mini-open technique is superior to the arthroscopic procedure when aiming to restore the athlete's original level of sports activity.

Minimally invasive reconstruction of acute acromioclavicular joint injuries using the TwinBridge button system.

INTRODUCTION: Acute acromioclavicular joint (ACJ) injuries are among the most common shoulder injuries in active young adults. The most frequently used surgical treatments include the hook plate implantation and arthroscopic treatment using flip-button systems. The aim of this study was to evaluate the results of treating acute ACJ injuries using a new minimally invasive implant based on a flip-button system. MATERIAL AND METHODS: From January 2016 to October 2019, a total of 20 patients with acute ACJ injuries (1 × Type III, 3 × Type IV, 16 × Type V) underwent surgery using the Twinbridge implant (Smith & Nephew). It is a prefabricated construct consisting of two Endobuttons connected with an UltraTape. One button is placed under the coracoid using a special aiming device and two buttons are placed on the clavicle. Preoperatively, 1 day postoperatively, 3 months and at least 1 year postoperatively, patients were clinically examined and bilateral stress view and axial radiographs were obtained. At final follow-up, the simple shoulder test (SST), Taft score, Constant score, and ACJ instability (ACJI) score were recorded and a side-to-side ratio of the coracoclavicular (CC) distance was calculated. RESULTS: All 20 patients were contacted at final follow-up at a mean of 28 (min. 13, max 50) months. Six patients were not willing to come for a clinical and radiographic examination and were contacted via telephone. All six patients were free of complaints. Another two patients free of complaints refused radiographs at final follow-up. The patients presented a mean SST of 99.6% (20 patients, min. 91.7, max. 100), Taft score of 11.6/12 points (12 patients, min. 10, max. 12), ACJI of 85.5/90 points (12 patients, min. 78, max. 90), and a Constant score of 97.1 (14 patients, min. 81.0, max. 100) for the affected shoulder. Preoperative stress view images revealed a mean side-to-side difference of the CC distance with a ratio of 1:2.34 (min. 1:1.80, max. 1:3.33). At final follow-up, CC distance was calculated with a mean ratio of 1:1.12 (min. 1.1, max. 1:1.38). Axial images showed a proper position in all cases. A "perfect" radiological result was achieved in six patients (50%) with a side-to-side CC distance of less than 10% (ratio 1:1.1 or less). A Rockwood type II result was achieved in five patients (42%) with a distance of 10 to 25% (ratio 1.11-1.25). One (8%) presented with a Rockwood type III result with a difference of more than 25% (ratio 1:1.38) and was considered a radiological failure. CONCLUSIONS: When used correctly, the Twinbridge implant offers good-to-excellent clinical and radiographic results using a minimally invasive surgical technique. Complication rate is comparable to other button-systems.

Sonographic Measurement of Dynamic Horizontal Instability in Acromioclavicular Joint Instability: Description of a Simple Technique and Correlation to Radiographic Parameters.

OBJECTIVE: Dynamic horizontal instability is considered to be the main reason for poor outcome after treatment for acromioclavicular (AC) joint instability. In this study, we describe a simple technique to quantify this pathology via sonography. METHODS: Thirty-six shoulders from 18 patients with ac joint instabilities were examined using modified Alexander views and a standardized sonographic examination. On the Alexander views, overlap of acromion and clavicle (OLAC), glenoid center to posterior clavicle distance (GCPC), and lateral extension (LE) were measured. Afterwards, the results were analyzed and compared with sonography. Posterior translation of the clavicle and the difference of translation between healthy and injured shoulder were evaluated. RESULTS: The mean age of the patients was 39 ± 14 years (range 19-61 years). We included 4 (22%) Rockwood type 3, 1 (6%) Rockwood type 4, and 13 (72%) Rockwood type 5 lesions. Four (22%) patients were female and 14 (78%) male patients. Posterior clavicle translation of the injured shoulder correlated strongly between OLAC and sonography (r = -0.514, P = .029), and the difference of translation between healthy and injured shoulder correlated very strongly between LE and sonography (r = 0.737, P < .001). CONCLUSION: The sonographic measurement technique for horizontal instability presented in this work could help detect horizontal instabilities. While the observation of dynamic horizontal displacement is a strength of this technique, measurements are hindered in cases of high coracoclavicular distances. LEVEL OF EVIDENCE: Level III-retrospective cohort study.

Fistula of acromioclavicular cyst treated with a staged reverse total shoulder arthroplasty: a case report.

BACKGROUND: Acromioclavicular (AC) joint cysts are relatively rare. There are two distinct etiologies of AC cysts. Type 1 is isolated to the AC joint, while type 2, is related to a tear or rupture of the rotator cuff (RC). The disease is usually a rare result of advanced AC joint arthritis or RC-tear arthropathy. Patients may present with signs and symptoms of RC impingement and tear. Conservative management may be used initially in asymptomatic individuals who are also not concerned with cosmesis. Aspiration and steroid injection of the cyst has been reported as one method of non-surgical management of these lesions, however, there is a high rate of recurrence. CASE PRESENTATION: We report a case of A 72-year-old right-handed female with past medical history of type two diabetes mellitus, chronic smoking, and a prior right RC repair with distal clavicle resection who presented with an AC joint cyst complicated by a draining fistula as a result of cyst aspiration and steroid injection. Due to the persistent drainage of the cyst and concern for infection, the patient was treated with a staged reverse shoulder arthroplasty given the setting of an irreparable rotator cuff tear and end-stage cuff-tear arthropathy. CONCLUSION: This case demonstrates an important complication of persistent draining fistula resulting from AC joint cyst aspiration and steroid injection in the setting of advanced RC-tear arthropathy. In immunocompromised patients, staged reverse shoulder arthroplasty should be considered for treatment of these draining fistulas especially when the concern for periprosthetic infection is high.

Current concepts in acromioclavicular joint (AC) instability - a proposed treatment algorithm for acute and chronic AC-joint surgery.

BACKGROUND: There exists a vast number of surgical treatment options for acromioclavicular (AC) joint injuries, and the current literature has yet to determine an equivocally superior treatment. AC joint repair has a long history and dates back to the beginning of the twentieth century. MAIN BODY: Since then, over 150 different techniques have been described, covering open and closed techniques. Low grade injuries such as Type I-II according to the modified Rockwood classification should be treated conservatively, while high-grade injuries (types IV-VI) may be indicated for operative treatment. However, controversy exists if operative treatment is superior to nonoperative treatment, especially in grade III injuries, as functional impairment due to scapular dyskinesia or chronic pain remains concerning following non-operative treatment. Patients with a stable AC joint without overriding of the clavicle and without significant scapular dysfunction (Type IIIA) may benefit from non-interventional approaches, in contrast to patients with overriding of the clavicle and therapy-resistant scapular dysfunction (Type IIIB). If these patients are considered non-responders to a conservative approach, an anatomic AC joint reconstruction using a hybrid technique should be considered. In chronic AC joint injuries, surgery is indicated after failed nonoperative treatment of 3 to 6 months. Anatomic AC joint reconstruction techniques along with biologic augmentation (e.g. Hybrid techniques, suture fixation) should be considered for chronic high-grade instabilities, accounting for the lack of intrinsic healing and scar-forming potential of the ligamentous tissue in the chronic setting. However, complication and clinical failure rates remain high, which may be a result of technical failures or persistent horizontal and rotational instability. CONCLUSION: Future research should focus on addressing horizontal and rotational instability, to restore native physiological and biomechanical properties of the AC joint.

Low rate of substantial loss of reduction immediately after hardware removal following acromioclavicular joint stabilization using a suspensory fixation system.

PURPOSE: To evaluate immediate loss of reduction in patients undergoing hardware removal after arthroscopically assisted acromioclavicular (AC) joint stabilization using a high-tensile suture tape suspensory fixation system and to identify risk factors associated with immediate loss of reduction. MATERIALS AND METHODS: Twenty-two consecutive patients with a mean age of 36.4 ± 12.6 years (19-56), who underwent hardware removal 18.2 ± 15.0 months following arthroscopically assisted stabilization surgery using a suspensory fixation system for AC joint injury between 01/2012 and 01/2021 were enrolled in this retrospective monocentric study. The coracoclavicular distance (CCD) as well as the clavicular dislocation/acromial thickness (D/A) ratio were measured on anterior-posterior radiographs prior to hardware removal and immediately postoperatively by two independent raters. Loss of reduction, defined as 10% increase in the CCD, was deemed substantial if the CCD increased 6 mm compared to preoperatively. Constitutional and surgical characteristics were assessed in a subgroup analysis to detect risk factors associated with loss of reduction. RESULTS: Postoperatively, the CCD significantly increased from 12.6 ± 3.7 mm (4.8-19.0) to 14.5 ± 3.3 mm (8.7-20.6 mm) (p < 0.001) while the D/A ratio increased from 0.4 ± 0.3 (- 0.4-0.9) to 0.6 ± 0.3 (1.1-0.1) (p = 0.034) compared to preoperatively. In 10 cases (45%), loss of reduction was identified, while a substantial loss of reduction (> 6 mm) was only observed in one patient (4.5%). A shorter time interval between index stabilization surgery and hardware removal significantly corresponded to immediate loss of reduction (11.0 ± 5.6 vs. 30.0 ± 20.8 months; p = 0.007), as hardware removal within one year following index stabilization was significantly associated with immediate loss of reduction (p = 0.027; relative risk 3.4; odds ratio 11.67). CONCLUSIONS: Substantial loss of reduction after hardware removal of a high-tensile suture tape suspensory fixation system was rare, indicating that the postoperative result of AC stabilization is not categorically at risk when performing this procedure. Even though radiological assessment of the patients showed a statistically significant immediate superior clavicular displacement after this rarely required procedure, with an increased incidence in the first year following stabilization, this may not negatively influence the results of ACJ stabilization in a clinically relevant way. LEVEL OF EVIDENCE: IV.

No difference in clinical outcome at 2-year follow-up in patients with type III and V acromioclavicular joint dislocation treated with hook plate or physiotherapy: a randomized controlled trial.

BACKGROUND: The need for operative treatment of acute acromioclavicular (AC) joint dislocation is unclear. The purpose of this randomized controlled trial was to compare the outcomes after operative treatment with a hook plate with the outcomes after nonoperative treatment of acute Rockwood type III and type V AC joint dislocations separately. METHODS: The inclusion criteria were patients aged 18-65 years with an acute type III or type V AC joint dislocation with the availability to start treatment within 3 weeks after trauma. All patients received the same standardized outpatient rehabilitation protocol and were followed up for 24 months. Assessments were based on radiographs, clinical examination findings, and questionnaires. The primary outcome was the Constant score (CS). The secondary outcomes were as follows: Subjective Shoulder Value (SSV), QuickDASH score (abbreviated version of the Disabilities of the Arm, Shoulder and Hand questionnaire), shoulder pain at rest and during movement rated using a visual analog scale, EQ-5D (European Quality of Life 5 Dimensions) score, patient satisfaction, cosmesis, complications, and adverse events. The 4 groups were compared using 1-way analysis of variance and intention to treat. RESULTS: The included patients (N = 124) (mean age, 40 years [range, 18-64 years]; 91% male patients) were randomized, stratified by type, to nonoperative treatment (type III, n = 33; type V, n = 30) or operative treatment with a hook plate (type III, n = 30; type V, n = 31) at a single center. Three patients randomized to physiotherapy dropped out before any follow-up measures, leaving 121 patients in the study. Complete clinical follow-up data were obtained from 118 patients at 24 months. At 3 months, patients in both nonoperatively treated groups had a significantly better mean CS, SSV, and QuickDASH score and had less pain at rest and during movement compared with patients treated operatively. At 6, 12, and 24 months, there were no significant differences in the CS, SSV, QuickDASH score, pain, or EQ-5D score between the groups regardless of intervention. At 24 months, the mean CS was 88 for nonoperatively treated type III patients vs. 91 for operatively treated type III patients and was 90 vs. 91 for type V patients (P = .477). At final follow-up, patients had regained 97% of the mean CS comparing the uninjured and injured shoulders and 86% of the patients rated the result as excellent or good. Eleven patients assigned to nonoperative treatment (18%, 6 type III and 5 type V) underwent surgery within 19 months. CONCLUSIONS: Both the nonoperative and operative treatment groups had very good restoration of shoulder function and patient satisfaction at 24 months, and operative treatment did not lead to better outcomes compared with nonoperative treatment. In conclusion, our study does not support surgery with a hook plate in patients with acute Rockwood type III or type V AC joint dislocations.

High Early-onset acromioclavicular secondary pathologies after acute arthroscopic joint reduction: a cohort study.

PURPOSE: The research aim was to determine the prevalence and risk factors of early secondary acromioclavicular (AC) joint disease in patients undergoing acute arthroscopic AC joint reduction and fixation and early complications of acute surgical treatment in patients with high-grade AC joint dislocation. METHODS: Overall, 102 patients diagnosed with Rockwood type V AC joint dislocation and undergoing arthroscopic coracoclavicular fixation were included. Early clinical and radiological complications were evaluated, as well as risk factors of secondary AC joint pathology. RESULTS: Twenty-nine patients (28%) presented with a secondary AC joint pathology, with 24 and 5 cases of osteolysis and osteoarthritis, respectively. The main complication was a loss of reduction of ≥ 1 mm (78%). Patients aged > 55 years were more likely to develop a secondary AC joint disease (odds ratios (OR) = 10.1, 95% confidence interval (CI): 1.42 - 72.55, p = 0.021). Patients with osteolysis (OR = 3.2, 95% CI 1.16 - 9.27, p = 0.025) or loss of reduction of > 5 mm (OR = 7.4, 95% CI 2.31 - 24.08, p = 0.001) were more likely to develop AC joint pain. Patients with an initial over-reduction were less likely to develop a subluxated AC joint (OR = 0.033, 95% CI 0.0021-0.134, p = 0.001) CONCLUSION: Age > 55 years and female sex were identified as risk factors of early-onset secondary AC joint disease. Osteolysis and a loss of reduction of > 5 mm were risk factors of AC joint pain but not of revision surgery. The main early complication was a loss of reduction of ≥ 1 mm. An initial over-reduction of the distal clavicle was a protective factor to avoid AC joint subluxation.