Quantification of dynamic posterior translation in modified bilateral Alexander views and correlation with clinical and radiological parameters in patients with acute acromioclavicular joint instability

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.

Efficacy of allogeneic tendon material coracoclavicular ligament reconstruction combined with Kirschner wire and titanium alloy hook plate material fixation in the treatment of acromioclavicular joint dislocation

Objective

To compare the effects of allogeneic tendon coracoclavicular ligament reconstruction combined with Kirschner wire fixation and clavicular hook plate fixation on early postoperative pain, postoperative shoulder joint function score and shoulder joint mobility in patients with acromioclavicular joint dislocation.

Methods

From January 2020 to January 2023, 43 patients with acromioclavicular joint dislocation admitted to Xi 'an Honghui Hospital were included. Among them, 24 patients were treated with the clavicular hook plate technique (Hook Plate,HP) group, and 19 patients were treated with allogeneic tendon coracoclavicular ligament reconstruction combined with the Kirschner wire technique (Allogeneic Tendon, AT) group. The Constant-Murley score of shoulder joint function 6 months after operation, postoperative shoulder joint activity, preoperative and postoperative pain, operation time, intraoperative blood loss and complications were compared between the two groups.

Results

All 43 patients were followed up for an average of 9.7 (9-12) months. The intraoperative blood loss in the allogeneic tendon group was less than in the hook plate group. The Constant-Murley shoulder function score was higher than that in the hook plate group 6 months after the operation. The abduction and lifting activity was greater than that in the hook plate group. The visual analogue scale scores at 3 days and 14 days after operation were lower than those in the hook plate group. The difference was statistically significant (p < 0.001). There was 1 case (5.3%) of exudation around the Kirschner needle track in the allogeneic tendon reconstruction group, and 5 cases (20.8%) of complications in the hook plate group, including 1 case of internal fixation stimulation, 2 cases of acromion impingement syndrome, 1 case of acromioclavicular joint osteoarthritis, and 1 case of shoulder joint stiffness. The complication rate of the allogeneic tendon group was lower than that of the hook plate group.

Conclusion

The clinical efficacy of allogeneic tendon coracoclavicular ligament reconstruction combined with Kirschner wire fixation in treating acromioclavicular joint dislocation (Rockwood type III-V) is better than hook plate internal fixation. The patients have less early postoperative pain and better recovery of shoulder joint function and shoulder joint mobility.

Management of Acute High-Grade Acromioclavicular Joint Dislocations: Comparable Clinical and Radiological Outcomes After Bidirectional Arthroscopic-Assisted Stabilization With the Single Low-Profile Suture Button Technique Versus Double-Suture Button Technique

PURPOSE

To compare the 2-year clinical and radiological outcomes of an arthroscopic-assisted bidirectional stabilization procedure using a single low-profile (LPSB) or double-suture button (DSB) technique with additional percutaneous acromioclavicular (AC) cerclage fixation for patients with acute high-grade AC joint dislocation.

METHODS

This retrospective cohort study compared male patients aged between 18 and 56 years with acute high-grade AC joint dislocation fixed with either a LPSB or DSB technique. Patients were examined at least 24 months after surgery. Subjective Shoulder Value (SSV), Taft (TF), and Acromioclavicular Joint Instability (ACJI) scores were evaluated. Coracoclavicular difference, ossification, AC joint osteoarthritis, and dynamic posterior translation (DPT) were assessed on bilateral anteroposterior stress radiographs and modified Alexander views. The revision rate due to implant conflict and duration of surgery were reported. Group outcome differences were analyzed using standardized hypothesis tests.

RESULTS

28 patients aged 39.2 (LPSB) and 36.4 years (DSB) (P = .319; CI: -2.77-8.34) were eligible per cohort. The follow-up was 30.5 (LPSB) and 37.4 months (DSB) (P = .02; CI: -12.73-1.08). LPSB patients rated a significantly higher SSV (93.2% vs 81.9% [DSB]; P = .004). TF and ACJI scores were similar between the groups. Coracoclavicular difference markedly decreased from 12 mm to 3 mm for both cohorts (P < .001). Ossification was identified in over 85% in both cohorts (P = .160; CI -0.77-0.13) and osteoarthritis in 21.4% (LPSB) and 39.3% (DSB) (P = .150). Persistent DPT was found in around 30% for both cohorts (P = .561; CI -0.26-0.48). The revision rates were 0% (LPSB) and 7% (DSB) (P = .491). LPSB surgery was shorter (59.7 vs 71.5 mins [DSB]) (P = .011).

CONCLUSIONS

The results of the LPSB and DSB techniques with additional percutaneous AC cerclage fixation showed comparable outcomes with excellent clinical and satisfactory radiological results. The assessment of the subjective patient satisfaction was in favor of the LPSB technique and no postoperative revision event was observed following this procedure.

LEVEL OF EVIDENCE

Level III, retrospective comparative therapeutic trial.

Position of scapula and clavicle in acute acromioclavicular joint dislocations: depressed scapula or elevated distal clavicle?

Background

Increased coracoclavicular distance due to acute acromioclavicular joint (ACJ) instability is often described as a pseudoelevation of the clavicle due to inferior hanging of the scapula, while the distal clavicle remains in its position. The aim of this study was to analyze whether the elevation of the distal clavicle, depression of the scapula, or both are associated with vertical instability and to evaluate the impact of weighted stress radiographs on the clavicle and scapular position in acute ACJ instabilities.

Methods

The cohort consisted of 505 patients (f = 52, m = 453; mean age 46 years) which presented to our emergency department or outpatient clinic and treated in our institution from 2006 to 2019 displaying an acute ACJ injury. The panorama views that displayed at least two vertebraes with their spinous processes were retrospectively evaluated. Two raters assessed the panorama views twice regarding the clavicular and coracoidal angle of both sides in relation to the cervicothoracal spine and the difference in height of both clavicles and coracoids.

Results

In our cohort, five types of displacement were distinguished: type A, only clavicle is elevated (N = 46); B, only scapula depressed (N = 36); C, the clavicle elevated and the scapula depressed (N = 67); D, both depressed (N = 133); and E, both elevated (N = 223). 123 patients had non-weighted radiographs and 353 patients stress views with 10 kg of axial load, whereas 29 patients had both radiological modalities. Among these 29 patients, a significant increase in coracoclavicular distance difference, clavicle, and scapula height (P < .05, respectively) was observed, when non-weighted radiographs were compared with weighted. A total of 13 shifts could be observed during the Rockwood type comparison of non-weighted radiographs with the weighted: six from Rockwood type II to III, two from type III to V, and five from type V to type III.

Conclusion

Acute injury to the ACJ does not exclusively lead to a depression of the scapula or an elevated distal clavicle but rather leads to various vertical displacement combinations, however mostly to the elevation of both structures possibly due to muscle spasm and pain. Comparing both radiological modalities of the same patients, the routine use of weighted views should be questioned, since often a shift of Rockwood stage can be observed might lead to on the one hand inadequate conservative treatment for underestimated injuries however on the other hand unnecessary surgery for overestimated dislocations.

Dynamic Horizontal Instability of the Acromioclavicular Joint: A Case Report

CASE

A 19-year-old female patient with a history of shoulder trauma 6 years ago presented with dynamic horizontal instability of the acromioclavicular joint (ACJ). She was treated with open ACJ reconstruction using gracilis allograft and showed a satisfactory clinical result at 1-year follow-up.

CONCLUSION

Dynamic pure horizontal instability of the ACJ is a rare entity with only 6 cases reported in the literature. Till now, all reported patients who necessitated surgical treatment failed because of residual instability and/or pain. We present the seventh case of this type with a successful clinical outcome.

[Minimally Invasive Techniques for the Treatment of Acute and Chronic Acromioclavicular Joint Instabilities]

Acromioclavicular joint instabilities are one of the most common injuries of the shoulder girdle. Diagnostic measures include the vertical and horizontal components of instability. The main goals of treatment include pain reduction, joint stabilization, and return to physical activity. For operative treatment, there are numerous techniques available. Recently, minimally-invasive techniques were developed and showed equal results as with open approach. These procedures facilitate simultaneous treatment of concomitant shoulder lesions and reduce soft tissue trauma as well as the risk of infection. This article presents an overview of such minimally-invasive techniques for both acute and chronic instabilities. Both techniques address the aspect of horizontal instability, which was found to compromise clinical results. For an acute injury, we describe the use of a low-profile button system combined with an additional acromioclavicular cerclage. In the chronic setting with a bidirectional (vertical and horizontal) instability, a free tendon graft combined with a single TightRope augmentation is recommended.

Acromioclavicular Joint Injuries in Sport

ABSTRACT

Sport-related shoulder injuries, including disruptions to the acromioclavicular joint (ACJ), are common. An ACJ injury is classified by the degree and direction of the clavicle displacement. Although the diagnosis can be made clinically, standard radiographic views are important to determine the severity of the ACJ disruption and assess for concurrent injuries. The majority of ACJ injuries can be managed nonoperatively; however, surgical treatment is indicated in some cases. Long-term outcomes are generally favorable for most ACJ injuries, and athletes generally return to sport without functional limitations. This article provides an in-depth discussion regarding all aspects of ACJ injuries, including clinically relevant anatomy, biomechanics, evaluation, treatment, and complications.

The Reliability of Acromioclavicular Joint Dislocation Classification Systems: A Comparison Between the Rockwood and Kraus Classifications

Background

The Rockwood system for the classification of acute acromioclavicular (AC) joint dislocations has been associated with a lack of reliability. A novel system has been proposed (Kraus classification) that is based on dynamic posterior translation of these injuries.

Purpose

To assess the interobserver and intraobserver reliability of the Rockwood and Kraus classification systems and also to examine the impact of surgeon experience on the assessments.

Study Design

Cohort study (diagnosis); Level of evidence, 3.

Methods

Included were 45 patients with acute AC joint injuries who underwent a radiographic examination using standard bilateral AP and modified Alexander views. For interobserver reliability, 6 shoulder surgeons (expert group) and 6 orthopaedic residents (novice group) reviewed the radiographs to classify injuries according to the Rockwood and Kraus classifications; for each categorization, the participants chose between nonoperative management and surgical treatment. The evaluation was repeated 6 weeks later to determine intraobserver reliability. Kappa (κ) coefficients and their 95% CIs were used to compare interobserver and intraobserver reliability for each classification system according to assessor experience. Statistical differences were considered significant when the upper and lower boundaries of the 95% CI did not overlap.

Results

The overall interobserver agreement for diagnosis (both novice and expert groups) was moderate (κ = 0.52 [95% CI, 0.51-0.54]) for the Rockwood classification and substantial (κ = 0.62 [95% CI, 0.53-0.65]) for the Kraus classification; however, no significant differences were observed between the κ values. The overall interobserver agreement for treatment selection was substantial when using both the Rockwood (κ = 0.78 [95% CI, 0.72-0.81]) and Kraus (κ = 0.77 [95% CI, 0.66-0.87]) classifications. The overall intraobserver agreement for diagnosis was substantial using both the Rockwood (κ = 0.65 [95% CI, 0.61-0.67]) and Kraus (κ = 0.73 [95% CI, 0.69-0.75]) classifications. There were no significant differences between the novice and expert groups on any of the evaluations.

Conclusion

The Kraus system was slightly more reliable than the Rockwood system for classifying AC joint injuries both between assessor groups and overall. The level of surgeon experience had no impact on the evaluations.

Reliability of the ISAKOS Modification to Subclassify Rockwood Type III Acromioclavicular Joint Injuries

Background

To improve clinical management, the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) developed a specific subclassification of Rockwood type III acromioclavicular (AC) injuries: IIIA (no overriding distal clavicle) and IIIB (overriding distal clavicle).

Purpose/Hypothesis

The study aimed to determine the inter- and intraobserver reliability of the radiographic classification proposed by ISAKOS for AC injuries. It was hypothesized that the strength of agreement for the ISAKOS modification will be substantial to almost perfect.

Study Design

Cohort study (diagnosis); Level of evidence, 3.

Methods

We evaluated 40 radiographs of all types of AC joint injuries from patients at a single institution. The images were distributed to 6 shoulder and elbow fellowship-trained orthopaedic surgeons, along with standardized assessment questionnaires. The evaluators measured the bilateral coracoclavicular distance and the coracoclavicular ratio and classified the severity of the injuries according to the modified ISAKOS Rockwood classification. Four of the surgeons repeated the evaluation 6 weeks later to calculate intraobserver agreement. The kappa (κ) statistic was calculated for categorical inter- and intraobserver reliability. Intraclass correlation coefficient (ICC) estimates were calculated for the reliability of the coracoclavicular distance measurement. A 2-tailed test was performed to assess statistical significance.

Results

Overall interobserver agreement was substantial (κ = 0.637; 95% CI, 0.595-0.680) among the 6 evaluators, and intraobserver agreement was also substantial among the 4 evaluators (κ = 0.616; 95% CI, 0.549-0.638). The interobserver agreement for evaluating types IIIA and IIIB was fair (κ = 0.215; 95% CI, 0.135-0.295) and moderate (κ = 0.473; 95% CI, 0.393-0.553), respectively. The agreement on the coracoclavicular distance measurements was excellent among the 6 evaluators on both the affected side (ICC, 0.982; 95% CI, 0.970-0.990) and the unaffected side (ICC, 0.930; 95% CI, 0.894-0.958).

Conclusion

Substantial agreement was found when categorizing AC joint injuries using the ISAKOS modification of the Rockwood classification, with excellent reliability demonstrated for the quantitative assessment of vertical displacement of the clavicle. Visual examination was unreliable in differentiating type IIIA injuries from type IIIB injuries.

Clinical and anatomical outcomes of isolated coracoclavicular fixation after acromioclavicular joint injury: is it stable enough or is additional horizontal fixation necessary?

Background

Recently, an emphasis has been put on anatomical reduction of acromioclavicular (AC) joint both in vertical and hortizontal planes for management of AC joint injuries due to persisting horizontal instability. Therefore, an additional AC fixation in horizontal plane has been recommended. However, relation between horizontal AC joint instability and clinical outcomes is still controversial. This study aims to evaluate outcomes of isolated coraco-clavicular fixation using arthroscopic assisted single coraco-clavicular tunnel technique in grade III and V AC joint injuries and to investigate the correlation between anatomical and clinical outcomes.

Methods

This study was conducted with 19 patients with grade III or V AC joint injury. Clinical outcomes included postoperative pain intensity and functional outcomes (Constant Score, American Shoulder and Elbow Surgeons, and Subjective Shoulder Value). Radiological evaluations were performed using radiographs and postoperative computed tomography scans. Degree of initial injury and postoperative stability both on axial and coronal planes were evaluated after radiological assessment. Correlations between anatomical and clinical outcomes were investigated using Pearson's correlation test.

Results

At the final follow-up assessment, the mean pain score was 1.8 ± 1.8, mean American Shoulder and Elbow Surgeons score was 81.0 ± 15.4, mean Subjective Shoulder Value was 81.3 ± 19.6, and mean Constant Score was 86.3 ± 14.8. The mean loosening ratio and AC distance were 43.5 ± 30.6% and 4.3 ± 12.4 mm, respectively. No correlation was observed between postoperative anatomical and clinical outcomes (P > .05).

Conclusion

Additional AC fixation on horizontal plane is not a prerequisite for all injuries, there is no significant association between horizontal instability and clinical outcomes and indications of an additional AC fixation needs to be determined.

The Morphology of the Acromioclavicular Joint Does Not Influence the Postoperative Outcome Following Acute Stabilization—A Case Series of 81 Patients

Purpose

To specifically evaluate the influence of the acromioclavicular (AC)-joint morphology on the outcome after arthroscopically assisted coracoclavicular (CC) stabilization surgery with suspensory fixation systems and to investigate whether an additional open AC-joint reduction and AC cerclage improves the clinical outcome for patients with certain morphologic AC-joint subtypes.

Methods

Patients with an acute acromioclavicular joint injury, who underwent arthroscopically assisted CC stabilization with suspensory fixation systems with or without concomitant AC cerclage between January 2009 and June 2017 were identified and included in this retrospective cohort analysis. AC-joint morphology was assessed on preoperative radiographs and categorized as “flat” or “non-flat” (“oblique”/“curved”) subtypes. After a minimum of 2 years of follow-up, postoperative Single Assessment Numeric Evaluation (SANE), American Shoulder and Elbow Surgeons (ASES), and visual analog scale (VAS) scores for pain were collected. A subgroup analysis of clinical outcomes depending on the surgical technique and morphological subtype of the AC joint was performed.

Results

Eighty-one patients (95% male, mean age 35 ± 12 years) could be included at a mean follow-up of 57 ± 14 months. Radiographic assessment of AC-joint morphology showed 24 (30%) cases of flat type, 38 (47%) cases of curved type, and 19 (23%) cases of oblique morphology. Postoperatively, no clinically significant difference could be detected after the treatment of AC joint injury via CC stabilization with or without concomitant AC cerclage (VAS_rest: P = .067; VAS_max: P = .144, ASES: P = .548; SANE: P = .045). No clinically significant differences were found between the surgical techniques for the flat morphologic subtype (VAS_rest: P = .820; VAS_max: P = .251; SANE: P = .104; ASES: P = .343) or the non-flat subtype (VAS_res: P = .021; VAS_max: P = .488; SANE: P = .243, ASES: P = .843).

Conclusions

In arthroscopically assisted AC stabilization surgery with suspensory fixation systems for acute AC-joint injury, the AC-joint morphology did not influence the postoperative outcome, independent of the surgical technique. No clinical benefit of performing an additional horizontal stabilization could be detected in our collective at mid-term follow-up.

Level of Evidence

Level IV, therapeutic case series.

Is coracoclavicular ossification a complication or a good prognostic factor after surgical treatment of acromioclavicular joint injury?

Background

The purpose of this study was to investigate whether heterotopic ossification (HO) in the coracoclavicular (CC) space after surgical treatment of acromioclavicular joint (ACJ) injury is a complication or a sign of good prognosis.

Methods

Fifty-nine consecutive patients who underwent CC reconstruction with or without augmentation of the ACJ for acute ACJ injuries were analyzed. Postoperative American Shoulder and Elbow Surgeons (ASES) score, Constant score (CS), subjective shoulder value (SSV), and visual analog scale (VAS) results were evaluated. For radiological evaluation, HO was evaluated, and CC distances were measured.

Results

Fifty-one patients (11 women and 40 men; mean age, 36 years [range, 17-68 years]) were evaluated after a mean follow-up of 3 years (range, 2-8 years). The mean ASES score at the follow-up was 82.73 (range, 51.6-100), mean CS was 85 (range, 50-100), mean SSV was 80 (range, 40-100), and mean VAS was 1.9 (range, 0-5). It was observed that the clinical outcomes (ASES, CS, SSV, VAS) of patients who developed ossification in the CC space were better than those who did not although it was not statistically significant. No statistically significant differences were found in the clinical outcomes (ASES, CS, SSV, VAS) between patients who underwent CC reconstruction without augmentation of the ACJ and those who were combined (P > .05).

Conclusion

HO in the CC space is a common finding following AC joint fixation injury. We suggest that HO is not a complication and might possibly have positive effects on clinical outcomes.

The “Chiang Mai Lean Forward” Radiographic View for Acromioclavicular Joint Injuries: A Cadaveric Study

Background:

Operative treatment is suggested for unstable type 3 acromioclavicular (AC) joint injuries; however, there is no clear consensus regarding the definition of an unstable type 3 injury. We propose a new radiographic method, the “Chiang Mai lean forward” view, to verify horizontal displacement in an unstable AC joint injury.

Hypothesis:

A radiograph taken with the torso leaning forward would allow the detection of a higher proportion of AC joint injuries.

Study Design:

Descriptive laboratory study.

Methods:

A total of 20 shoulders from 10 fresh whole-body cadaveric specimens (mean age, 68.8 years) were tested at 3 different torso leaning angles (30°, 45°, and 60°) to determine the best position for projecting the x-ray beam. The shoulders were dissected sequentially starting with the AC ligament (stage 1), then additional sectioning of the partial coracoclavicular (CC) ligament with either the trapezoid ligament cut first (stage 2A) or the conoid ligament cut first (stage 2B), and finally complete sectioning of the CC ligament (stage 3). Radiography was performed after each stage to evaluate the degree of displacement of the anterior border of the acromion relative to the anterior border of the clavicle. Paired t tests were used to compare the degree of displacement at each stage to that of the shoulder before cutting.

Results:

Leaning at an angle of 30° provided better visualization of the AC joint in the “Chiang Mai lean forward” view. Compared with the intact condition, complete isolated cutting of the AC ligament produced 5.21 mm of horizontal displacement of the AC joint (P < .0001), complete tearing of the AC ligament and partial cutting of the CC ligament resulted in a displacement of <12 mm (7.91 mm at stage 2A [P = .0003] and 8.10 mm at stage 2B [P = .0013]), and complete tearing of both the AC and the CC ligaments resulted in a displacement of 26.37 mm (P < .0001).

Conclusion:

The “Chiang Mai lean forward” radiographic view is a potentially useful tool for determining the degree of the injury and the stability of the AC joint.

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.

Kinematic Alterations in the Shoulder Complex in Rockwood V Acromioclavicular Injuries During Humerothoracic and Scapulothoracic Movements: A Whole-Cadaver Study

BACKGROUND

Previous cadaveric kinematic studies on acromioclavicular injuries described mainly rotational differences during humerothoracic movements. Although isolated scapulothoracic movements are also often performed during activities of daily life and can be painful after acromioclavicular injuries, they have not been extensively studied. Further, the analysis of joint translations in kinematic studies has received little attention compared with biomechanical studies.

HYPOTHESIS

A kinematic analysis of joint motions in the intact shoulder versus a shoulder with Rockwood V injury would demonstrate a different pattern of kinematic alterations during humerothoracic and scapulothoracic movements.

STUDY DESIGN

Descriptive laboratory study.

METHODS

A kinematic analysis was performed in 14 cadaveric shoulders during 3 humerothoracic passive movements (coronal and sagittal plane elevation and horizontal adduction) and 3 scapulothoracic passive movements (protraction, retraction, and shrug). An optical navigation system registered rotational motions in the sternoclavicular, scapulothoracic, and acromioclavicular joints in the intact and Rockwood V conditions. In the acromioclavicular joint, mediolateral, anteroposterior, and superoinferior translations were also analyzed.

RESULTS

In the Rockwood V condition, a significant increase in clavicular elevation in the sternoclavicular joint during both humerothoracic and scapulothoracic movements was demonstrated, whereas a significant decrease in posterior rotation of the clavicle occurred only during humerothoracic movements. In the scapulothoracic joint, the scapular position changed most significantly during protraction. In the acromioclavicular joint, the scapular tilting position was altered significantly during both humerothoracic and scapulothoracic movements, whereas the scapular rotational position changed only during coronal and sagittal plane elevation. The largest significant changes in the scapular protraction position were seen during protraction movement. Further, in the acromioclavicular joint there was a significant inferior translation of the scapula during all motions, a significant anterior translation during protraction and horizontal adduction, and a significant posterior translation during coronal plane elevation. Mediolaterally, the acromial end of the scapula slid further under the distal clavicle during protraction than during horizontal adduction.

CONCLUSION

Large kinematic differences were seen between the intact state and a Rockwood V lesion not only during humerothoracic movements but also during scapulothoracic movements in the cadaveric model. During humerothoracic movements, rotational differences were mainly caused by alterations in the clavicular position. In contrast, during protraction, the alterations in the scapular position were the dominant factor.

CLINICAL RELEVANCE

This study demonstrates that protraction induces larger kinematic alterations than horizontal adduction in acromioclavicular injuries and can therefore be included in both clinical examination and kinematic analyses to identify lesions more clearly.

Concomitant Acromioclavicular and Coracoclavicular Ligament Reconstruction with a Duo-Figure-8 Autogenic Graft Wrapping Technique for Treating Chronic Acromioclavicular Separation

Backgroud

Coracoacromial ligament transfer is the traditional procedure for treating chronic acromioclavicular separation, but it is significantly inferior to ligament reconstruction according to biomechanical and clinical studies. However, ligament reconstruction carries the risk of complications of graft loosening and peri-tunnel fractures. Currently, there is no ligament reconstruction procedure optimal for preventing such complications. The purpose of this study was to describe and retrospectively analyze the clinical and radiological outcomes of a “duo-figure-8” autogenic graft wrapping technique, which was used to concomitantly reconstruct the acromioclavicular and coracoclavicular ligaments.

Methods

Preoperative, immediate postoperative, and final follow-up oputcomes were evaluated in 10 enrolled patients. Radiographic outcomes were indicated by the bilateral difference of the coracoclavicular distance (CCD) and overlapping length of the acromioclavicular joint (OLac). Quality of reduction was classified into 4 grades according to bilateral CCD difference into overreduction (< 0 mm), anatomic reduction (0–4 mm), partial loss of reduction (4–8 mm), and recurrent dislocation (> 8 mm). Clinical outcomes were evaluated using the American Shoulder and Elbow Surgeons (ASES) and Constant scores.

Results

The mean side-to-side differences for CCD were 11.9 mm (preoperative), −0.1 mm (immediate postoperative), and 3.4 mm (final follow-up); those for OLac were 9.4 mm (preoperative) and 2.7 mm (final follow-up). CCD and OLac outcomes significantly improved at final follow-up (p < 0.05). At the immediate postoperative stage, 6 and 4 patients had overreduction and anatomic reduction, respectively. At final follow-up, 7 and 3 patients had anatomic reduction and partial loss of reduction, respectively. The magnitude of improvement of ASES scores for patients with anatomic reduction and partial loss of reduction (p = 0.20) was 18.1 and 20.0, respectively. The magnitude of improvement of Constant scores in patients with anatomic reduction and partial loss of reduction (p = 0.25) was 19.9 and 22.3, respectively.

Conclusions

The technique yielded acceptable functional outcomes in patients with anatomic reduction or partial loss of reduction. The “duo-figure-8” wrapping method—a single autogenic tendon graft passing beneath the coracoid process with a tendon-knot fixation over the distal clavicle and looping around the acromion intramedullary—did not increase the risk of peri-tunnel fractures over the clavicle, coracoid process, or acromion.

Long-term stability of coracoclavicular suture fixation for acute acromioclavicular joint separation

PURPOSE

The optimal (SBJI) surgical treatment for acute acromioclavicular (AC) joint disruption remains controversial. What is being presented is the long-term functional outcomes of a double cross-looped coracoclavicular (CC) suture technique with the intention of restoring both anteroposterior and superior displacement of the clavicle.

METHODS

Between 2007 and 2016, 81 patients underwent surgical reconstruction for acute acromioclavicular joint (AC) disruption in two orthopaedic centers. Two patients died for reasons unrelated to the treatment, and seven missed the final follow-up appointment, leaving 72 patients (67 males; 5 females; age 37 ± 12.4; range 15-64 years) for clinical and radiological assessments. All cases were classified according to the Rockwood classification as type III (n = 34), IV (n = 14) or V (n = 24). The dislocation was repaired with double cross-looped CC fixation using four Ethibond sutures passing underneath the coracoid and through a 4.5 mm drill hole in the clavicle in opposing directions to control both anteroposterior and vertical displacement. Radiological investigation preoperatively and at the last follow-up included anteroposterior and/or Zanca views, axillary or Alexander views, and comparative stress radiography of both AC joints. Patients were evaluated clinically with the Constant-Murley score (CMS) and Acromio Clavicular Joint Instability Score (ACJIS). Loss of reduction, subluxation, CC ligament ossification, post-traumatic arthritis, and peri-implant fractures were also recorded.

RESULTS

Seventy-two patients were available for the last clinical and radiological evaluations. At a median follow-up period of 6.3 ± 2.1 years (range 3-12 years), the CMS and ACJIS were 92.1 ± 7.2 (range 60-100 points) and 90.4 ± 8.6 (range 45-100 points), respectively. Complications included 9 (12.5%) patients with slight loss of reduction, 2 (1.7%) with dislocation recurrence, 1 (1.3%) with superficial infection, 1 (1.3%) with a fracture of the lateral end of the clavicle, and 2 (1.7%) with persistent tenderness in the AC joint. The incidence of periarticular ossification was 22.4% and did not affect the final outcome.

CONCLUSIONS

This technique represents an effective and low-cost treatment for acute AC joint separations.

LEVEL OF EVIDENCE

IV.

Weighted or internal rotation radiographs are not useful in the classification of acromioclavicular joint dislocations

BACKGROUND

Weighted radiographs are performed to classify acromioclavicular joint dislocations; however, the evidence regarding their usefulness is conflicting. Laboratory studies suggest that internal rotation views can replace weighted radiographs, but this has not been clinically evaluated.

PURPOSE

To evaluate whether weighted or internal rotation radiographs uncovers more high-grade acromioclavicular joint dislocations than non-weighted radiographs.

MATERIAL AND METHODS

A total of 162 patients with acromioclavicular joint dislocations were prospectively included. After applying exclusion criteria, 140 remained. Three panorama radiographs, including both coracoclavicular intervals, were completed of each participant: first, a weighted radiograph with 5-kg weights suspended from the wrists; second, a non-weighted radiograph; and third, an internal rotation radiograph. The coracoclavicular intervals were measured by two radiologists independently, and measurements were translated into Rockwood classifications. The classifications and measurements derived from the different radiographic views were compared.

RESULTS

Weighted radiographs caused no significant changes in classification. For the internal rotation views, there was a significant change in classification for radiologist 2; however, the reason was that more injuries were downgraded compared to the non-weighted views. Relative to the non-weighted radiographs, the mean increase of the coracoclavicular interval on the injured side in the weighted view was 0.5 mm (95% confidence interval [CI] 0.37-0.65) and in the internal rotation view 0.2 mm (95% CI 0.04-0.33). While these changes were statistically significant, they were small and not clinically important.

CONCLUSION

This study does not support the use of weighted and internal rotation radiographs in the classification of acromioclavicular joint dislocations.

Evaluation of the Circles Measurement and the ABC Classification of Acromioclavicular Joint Injuries

BACKGROUND

Acromioclavicular joint (ACJ) injuries are common. Despite this, it remains unclear how best to assess, classify, and manage these cases. A simple, reliable, valid, and accurate radiographic parameter to measure ACJ displacement would allow improved consistency of diagnosis and subsequent treatment pathways.

PURPOSE

To evaluate "the circles measurement" and associated "ABC classification" as a tool for assessing ACJ displacement and injury classification.

STUDY DESIGN

Descriptive laboratory study.

METHODS

The circles measurement is taken from a lateral Alexander radiograph of the shoulder. The measurement is the center-to-center distance between 2 circles drawn to define the lateral extent of the clavicle and the anteromedial extent of the acromion; it is independent of the displacement plane, judging total ACJ displacement in any direction rather than trying to quantify vertical and/or horizontal displacement. When utilized clinically, the circles measurement is a single measurement calculated as the difference between values recorded for the injured and uninjured sides. Validation of the circles measurement was performed using lateral Alexander radiographs (including ±20° projection error in all planes) and computed tomography of standardized ACJ injury simulations. We assessed inter- and intrarater reliability, convergent validity, and discriminant validity of the circles measurement and subsequently generated a classification of ACJ injury based on displacement.

RESULTS

Reliability and validity of the circles measurement was excellent throughout. Interrater reliability (ICC [intraclass correlation coefficient] [2,1], 95% CI; n = 78; 4 observers) was 0.976 (0.964-0.985). Intrarater reliability (ICC [2,1]; 95% CI; n = 78; 2 measures) was 0.998 (0.996-0.998). Convergent validity (Pearson correlation coefficient, r) was 0.970 for ideal radiographs and 0.889 with ±20° projection error in all planes. Discriminant validity, with 1-way analysis of variance, showed a P value of <.0001 and effect size (η²) of 0.960, with the ability to distinguish between the previously defined stable (Rockwood IIIA) and unstable (Rockwood IIIB) injuries. The results permitted objective, statistically sound parameters for the proposed ABC classification system.

CONCLUSION

The circles measurement is a simple, reliable, valid, accurate, and resilient parameter for assessing ACJ displacement and can be used in conjunction with the proposed ABC classification to define ACJ injuries more accurately and objectively than previously described.

CLINICAL RELEVANCE

This novel parameter has the potential to standardize the initial assessment and possibly the subsequent clinical management of ACJ injuries, in addition to providing a standardized measure for future research.

The ligamentous injury pattern in acute acromioclavicular dislocations and its impact on clinical and radiographic parameters

BACKGROUND

Acromioclavicular (AC) joint dislocations are classified according to the Rockwood (RW) classification, which is based on radiographic findings. Several authors have suggested magnetic resonance imaging (MRI) for visualization of the capsuloligamentous structures stabilizing the AC joint. The aim of this study was to describe the ligamentous injury pattern in acute AC joint dislocations by MRI and investigate associations with clinical and radiographic parameters.

METHODS

This prospective study included 45 consecutive patients (5 women and 40 men; mean age, 33.6 years [range, 19-65 years]) with an acute AC joint separation (RW type I in 5, RW type II in 8, RW type III in 18, and RW type V in 14). All patients underwent physical examination of both shoulders, and clinical scores (Subjective Shoulder Value, Constant score, Taft score, and Acromioclavicular Joint Instability Score) were used to evaluate the AC joint clinically as well as radiographically. Post-traumatic radiography included bilateral anteroposterior stress views and bilateral Alexander views to evaluate vertical instability and dynamic posterior translation. MRI was performed for assessment of the AC and coracoclavicular (CC) ligaments and the delto-trapezoidal fascia.

RESULTS

Radiographic and MRI classifications were concordant in 23 of 45 patients (51%), whereas 22 injuries (49%) were misjudged; of these, 6 (13%) were reclassified to a more severe type and 16 (36%), to a less severe type. The integrity of the CC ligaments was found to have a clinical impact on vertical as well as horizontal translation determined by radiographs and on clinical parameters. Among patients with an MRI-confirmed complete disruption of the CC ligaments, 68% showed a radiographic CC difference > 30% and 75% showed complete dynamic posterior translation. Inferior clinical parameters were noted in these patients as compared with patients with intact CC ligaments or partial disruption of the CC ligaments (Constant score of 67 points vs. 49 points [P < .05] and Acromioclavicular Joint Instability Score of 51 points vs. 23 points [P < .05]). The inter-rater and intra-rater reliability for assessment of the ligamentous injury pattern by MRI was fair to substantial (r = 0.37-0.66).

CONCLUSION

The integrity of the CC and AC ligaments found on MRI has an impact on clinical and radiographic parameters.

Ultrasound Evaluation of Anterior Acromioclavicular Relationship in the Horizontal Plane on 40 Healthy Subjects. A New Possibility for Differential Diagnosis of Acromioclavicular Disjunctions Rockwood Stage 3 and 4? A Pilot Study

OBJECTIVE

To evaluate the repeatability and reproducibility of an ultrasound examination of the acromioclavicular joint (ACJ) performed by an orthopaedic surgeon to analyze anterior ACJ relationship in the horizontal plane.

DESIGN

Prospective observational study on healthy subjects.

SETTING

The study was conducted in 2017 in a university department of orthopaedic surgery and traumatology.

LEVEL OF EVIDENCE

III.

PATIENTS (OR PARTICIPANTS)

Forty consecutive volunteers aged 18 to 40 years were involved. INTERVENTIONS (OR ASSESSMENT OF RISK FACTORS OR INDEPENDENT VARIABLES):: The ultrasound examination was performed by 2 orthopaedic surgeons with a SonoSite M-Turbo portable ultrasound machine (Fujifilm, Japan). Distance measurement between the anterior edge of the clavicle (AECL) and the anterior edge of the acromion (AEAC) was done on the right side, then on the left one and repeated by the same examiner.

MAIN OUTCOME MEASURES

The intra- and interexaminer reproducibility of measurements was analyzed as primary outcome. Concordance of distance measurements between the right and left sides on the same subject was evaluated, as well as the "typical morphology" of the ACJ in the horizontal plane.

RESULTS

The intra- and interexaminer reproducibility for AECL-AEAC distance measurements was, respectively, 0.95 (0.93-0.97) and 0.87 (0.84-0.90). The correlation between the right and left sides was significant (P < 0.001), with a reproducibility of 0.86 (0.83-0.89). Twenty-seven (67.5%) volunteers were considered to have a "perfect alignment" of the AECL and AEAC.

CONCLUSIONS

This study confirms that it is possible to evaluate with good reproducibility the anterior AC relationship in the horizontal plane and that both sides are similar on the same subject.

Restoring Horizontal Stability of the Acromioclavicular Joint: Open Acromioclavicular Ligament Reconstruction and Repair With Semitendinosus Allograft

Injuries to the acromioclavicular (AC) joint are common and comprise ∼12% of shoulder injuries. Stability to the AC joint depends on the coracoclavicular (CC) ligaments for vertical stability and AC ligaments and capsular structures for horizontal stability. Injuries to the AC ligaments can lead to horizontal instability of the AC joint. There is no gold standard technique for treating these injuries surgically, and many of the described procedures focus on vertical instability rather than horizontal instability. This article describes an open AC ligament reconstruction with semitendinosus allograft to restore horizontal stability of the AC joint.

Methods used to assess the severity of acromioclavicular joint separations in Japan: a survey

Background

In acromioclavicular joint (ACJ) separations, patient characteristics determine the indications for surgery. However, in Japan, classification methods used to assess the severity of ACJ separations differ between institutions, and even within a classification method, different interpretations can lead to different assessments of severity. Therefore, in this study, we conducted an email survey of Japan Shoulder Society (JSS) members regarding their assessment methods for ACJ separation severity.

Methods

A questionnaire about methods for assessing the severity of ACJ separations was emailed to JSS members (1655) including 59 JSS councilors. The survey focused on diagnostic imaging methods, classifications of severity assessments, and methods of assessing severity.

Results

In total, 183 responses were received. All respondents used an anteroposterior view of the ACJ. Severity assessments were classified by the Tossy classification (57 respondents), Rockwood classification (141 respondents), and other classifications (7 respondents) including duplication. Of the 141 respondents using the Rockwood classification, 119 diagnosed type III as ACJ dislocation when the inferior clavicle border translated above the superior acromial border, whereas 56 used the coracoclavicular distance. However, to diagnose type V, 118 respondents used the coracoclavicular distance whereas 38 used palpation. To diagnose type IV, 57 respondents considered all cases in which the clavicle translated posterior to the acromion, even when vertical ACJ dislocation occurred simultaneously. However, 88 respondents did so in the presence of posterior clavicle displacement and ACJ subluxation.

Conclusion

The Rockwood classification is commonly used for severity assessments in Japan; however, there is some disagreement regarding the assessment for the diagnosis of type IV. Methods to diagnose both superior and posterior translation of the clavicle need further debate.

Horizontal Instability of the Acromioclavicular Joint: A Systematic Review

BACKGROUND

Injuries to the acromioclavicular (AC) joint are common and should be suspected in patients who have shoulder pain in the region of the acromion and clavicle. Injuries to the AC ligament can cause horizontal instability and are often neglected or underdiagnosed, which can lead to poor patient outcomes.

PURPOSE

To perform a systematic review of the literature on the diagnosis and treatment of horizontal instability of the AC joint.

STUDY DESIGN

Systematic review.

METHODS

The authors performed a systematic review using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. PubMed and EMBASE were searched for studies that investigated diagnosis, treatment, and failure of operative management of acute and chronic AC separations. Studies that did not specifically evaluate AC joint injuries, were not written in English, or were specific only to vertical instability of the AC joint were excluded.

RESULTS

Overall, 23 articles met the inclusion criteria and were therefore included in this systematic review. Diagnosing horizontal AC instability is difficult using plain radiographs; dynamic views were shown in some cases to better detect horizontal instability than with static views. More than 60 procedures for treating AC joint injuries have been published, but many focus on vertical rather than horizontal instability. Modifications to current surgical procedures to incorporate reconstruction of the horizontal component showed improved patient outcomes. Such modifications included additional AC joint suture cord cerclage, combined AC and coracoclavicular ligament reconstruction, and the Twin Tail TightRope triple button technique. Failure after surgical stabilization of AC joint separation has been reported to occur in 15% to 80% of cases.

CONCLUSION

No consensus is available regarding the best practices for diagnosis, evaluation, and treatment of acute or chronic horizontal instability of the AC joint. Moreover, horizontal instability injuries are often neglected or poorly understood, making diagnosis difficult, which may lead to high complication rates and failure after surgical stabilization.

Acromioclavicular joint augmentation at the time of coracoclavicular ligament reconstruction fails to improve functional outcomes despite significantly improved horizontal stability

PURPOSE

Acromioclavicular joint reconstruction is a well-established and frequently performed procedure. Recent scientific and commercial interest has led to a drive to develop and perform surgical techniques that more reliably restore horizontal stability in order to improve patient outcomes. The aim of this systematic review was to evaluate the biomechanical evidence for procedures directed at restoring horizontal stability and determine whether they are associated with superior clinical results when compared to well-established procedures.

METHODS

A review of the online databases Medline and EMBASE was conducted in accordance with the PRISMA guidelines on the 23rd December 2017. Biomechanical and clinical studies reporting either static or dynamic horizontal displacement following acromioclavicular joint reconstruction (Coracoclavicular reconstruction or Weaver-Dunn) were included. In addition, biomechanical and clinical studies reporting outcomes after additional augmentation of the acromioclavicular joint were included. The studies were appraised using the Methodological index for non-randomised studies tool.

RESULTS

The search strategy identified 18 studies eligible for inclusion: six biomechanical and 12 clinical studies. Comparative biomechanical studies demonstrated that acromioclavicular augmentation provided significantly increased horizontal stability compared to the coracoclavicular reconstruction and Weaver-Dunn procedure. Comparative clinical studies demonstrated no significant differences between coracoclavicular reconstruction with and without acromioclavicular augmentation in terms of functional outcomes (American Shoulder and Elbow Surgeon and Constant score), complication or revision rates. However, one comparative study did demonstrate an improvement in Taft (p = 0.018) and Acromioclavicular Joint Instability scores (p = 0.0001) after acromioclavicular augmentation.

CONCLUSION

In conclusion, coracoclavicular reconstruction with augmentation of the acromioclavicular joint has been shown to provide improved horizontal stability in both biomechanical and clinical studies compared to isolated coracoclavicular reconstruction. However, comparative studies have shown no clinical advantage with respect to American Shoulder and Elbow Surgeon or Constant scores and, therefore, the results of this systematic review do not support acromioclavicular augmentation in routine clinical practice.

LEVEL OF EVIDENCE

IV.

Acromioclavicular Joint Injuries: Evidence-based Treatment

Injuries to the acromioclavicular (AC) joint are common in the athletic patient population. Most AC joint injuries occur in young males, typically from a direct fall onto the superior aspect of the shoulder when the arm is adducted. Numerous publications describing joint anatomy and biomechanics, surgical techniques for reconstruction, and rehabilitation protocols are available to guide treatment strategies for injuries to the AC joint. Treatment is typically nonsurgical for type I and II injuries and surgical for type IV and VI injuries. Controversy surrounds the indications for nonsurgical versus surgical treatment of type III and V injuries. Multiple surgical techniques have been described, including coracoclavicular (CC) screw fixation, coracoacromial ligament transfer, and numerous methods of CC ligament reconstruction. Anatomic CC ligament reconstruction can be performed either open or arthroscopically, with and without graft augmentation. This article will discuss clinically relevant anatomy and biomechanical properties of the AC joint and will review decision-making principles and treatment options for common AC joint injuries. An updated summary of clinical outcomes after AC joint treatment will also be presented.

Primary versus revision arthroscopically-assisted acromio- and coracoclavicular stabilization of chronic AC-joint instability

BACKGROUND

A gracilis tendon autograft with TightRope-augmentation can be used for arthroscopically-assisted acromioclavicular (AC)- and coracoclavicular (CC-)stabilization of chronic bidirectional AC-joint instability after failed primary treatment. The impact of failed initial treatment on postoperative outcome is unclear. Hence, the purpose of this study was to evaluate it.

METHODS

Twenty-seven of 38 patients suffering from chronic AC-joint instability after either failed conservative (group 1) or surgical treatment (group 2) treated in the above-mentioned technique were finally included in this study. The Subjective Shoulder Value, the Constant Score, the Taft Score and the Acromioclavicular Joint Instability Score were used for clinical evaluation. Bilateral anteroposterior stress radiographs and bilateral Alexander views were obtained for radiological evaluation.

RESULTS

14 patients of group 1 [3f/11m; median age 47.6 (range 20.9-57.4) years] could be evaluated after a median follow-up of 24.3 (range 20-31.2) months and 13 patients of group 2 [6f/7m; median age 44.9 (range 24.9-61.0) years] were available after a median follow-up of 28.8 (range 20-33) months. Comparison of clinical score results revealed no significant differences between both groups. The median CC-difference showed no significant difference between the groups [group 1 0.8 (0-10.5) mm, group 2 0.9 (0-4.3) mm].

CONCLUSION

AC- and CC-stabilization of chronic bidirectional AC-joint instability using a gracilis tendon autograft with TightRope-augmentation can be recommended after failed conservative and surgical treatment.

STUDY DESIGN

Retrospective cohort study; Level of evidence III.

Risk of neurological injury in posterior bone block surgery for recurrent glenohumeral instability: a cadaveric study

INTRODUCTION

Recurrent posterior glenohumeral instability poses a challenge for treatment. Bone block procedures have been advocated in cases where a bony defect is present. However, these techniques are not free of complications due to the proximity of neurovascular structures. The aim of this study is to measure the distance to the axillary and suprascapular nerves at the different steps of the procedure.

MATERIALS AND METHODS

Ten frozen human cadavers were used. The bone graft was prepared and placed on the posterior aspect of the glenoid, where it was fixed with two K-wires in different positions: parallel to the articular surface and with 20° of medial angulation. The distance from the entry and exit points of the K-wires to the axillary and suprascapular nerves was measured.

RESULTS

At the exit point, mean distance from the superior K-wire to the axillary nerve was 4.4 mm in the neutral position and 14.4 mm when medially angulated (p = 0.01) and 2.6 mm and 11.5 mm, respectively, for the inferior K-wire (p < 0.01). No differences were found at the entry point (p = 0.7 and p = 0.3). For the suprascapular nerve, mean distance to the entry point of the superior K-wire was significantly greater when it was inserted with 20° of medial angulation than when placed in neutral position (p = 0.04). No differences were found for the inferior K-wire (p = 0.35).

CONCLUSION

Posterior bone block surgery should be performed taking into consideration the possibility of axillary nerve injury anteriorly at the exit point of the K-wires. Wire and screw insertion parallel to the glenoid articular surface may reduce the risk, while increased wire or screw medial angulation with respect to the glenoid surface may heighten risk.

LEVEL OF EVIDENCE

Not applicable (cadaveric study).

Dynamic instability of the acromioclavicular joint: A new classification for acute AC joint separation

Background

Acute acromioclavicular (AC) dislocation is classified according to Rockwood (RW). Although of clinical relevance, dynamic horizontal translation (DHT) is not listed in this classification or in frequently used clinical evaluation tools. The aim of this study was (a) to evaluate vertical and horizontal AC joint instabilities and assess their combined occurrence and clinical appearance in a consecutive group of patients, as well as (b) to develop a new classification of acute AC joint dislocation.

Method

A consecutive group of 61 patients (seven female, 54 male) with a mean age of 34.5 years (18.9–60.1) were included in the study. All patients underwent posttraumatic clinical—Taft Score (TF), Acromioclavicular Joint Instability Score (ACJI), Constant Score (CS), Subjective Shoulder Value (SSV)—and radiological (bilateral anteroposterior stress and bilateral Alexander views) evaluation.

Results

According to the RW classification, the following AC dislocations were present: eight (13.1%) type I, nine (14.8%) type II, 22 (36.1%) type III, and 22 (36.1%) type V. Based on the clinical and radiographic results, a new classification is proposed: Type I instabilities show only a partial vertical displacement (≤30% coracoclavicular distance [CCD]) and type II a complete vertical displacement (>30% CCD). Both type I and II are further graded into none or partial (A) and complete DHT (B) as seen on bilateral Alexander views.

Conclusion

DHT can be found in low-grade instabilities and lead to inferior clinical results in the posttraumatic situation.

[Current aspects and new techniques in dislocation of the shoulder joint]

With 12% of all injuries concerning the shoulder, acromioclavicular (AC) joint dislocations are a common injury especially in young and active patients. The Rockwood classification is widely accepted, which differentiates between six types depending on the degree of injury and the vertical dislocation. Because the classification does not adequately address the horizontal instability, its benefits are questionable and there is currently no consensus. For this reason, the classification and the therapy of these injuries are increasingly becoming the subject of scientific investigations. Whereas conservative treatment for type I and II injuries and operative treatment for type IV-VI injuries are widely accepted, there is still no agreement in treating type III lesions. The goal of this review article is to present the current evidence for the diagnostics, different classifications and therapeutic possibilities.

Combined arthroscopically assisted coraco- and acromioclavicular stabilization of acute high-grade acromioclavicular joint separations

PURPOSE AND HYPOTHESIS

Due to high rate of persisting dynamic posterior translation (DPT) following isolated coracoclavicular double-button technique for reconstruction of the acromioclavicular (AC) joint reported in the literature, an additional acromioclavicular cerclage was added to the procedure. The aim of this study was to evaluate the clinical and radiological results of patients with high-grade AC-joint instability treated with a double TightRope technique with an additional percutaneous acromioclavicular cerclage.

METHODS

Fifty-nine patients (6 f/53 m; median age 38.3 (range 21.5-63.4 years) who sustained an acute high-grade AC-joint dislocation (Rockwood type V) were treated using the above-mentioned technique. At the final follow-up, the constant score (CS), the subjective shoulder value (SSV), the Taft score (TF) and the acromioclavicular joint instability score (ACJI) as well as bilateral anteroposterior stress views with 10 kg of axial load and bilateral modified Alexander views were obtained.

RESULTS

At a median follow-up of 26.4 (range 20.3-61.0) months, 34 patients scored a median of 90 (33-100) points in the CS, 90 (25-100) % in the SSV, 11 (4-12) points in the TF and 87 (43-100) points in the ACJI. The coracoclavicular (CC) distance was 12.1 (6.5-19.8) mm and the CC difference 2.0 (0.0-11.0) mm. Two patients (5.8%) showed a complete DPT of the AC joint, and fourteen patients (41.1%) displayed a partial DPT. The overall revision rate was 11.7%. Two patients presented implant irritation, one patient a recurrent instability, and one patient suffered from a local infection.

CONCLUSION

The arthroscopically assisted and image-intensifier-controlled double TightRope technique with an additional percutaneous acromioclavicular cerclage leads to good and excellent clinical results after a follow-up of 2 years. The incidence of persisting dynamic horizontal translation is lower compared to isolated coracoclavicular stabilization. Thus, we recommend using the double TightRope implant with an additional acromioclavicular cerclage.

LEVEL OF EVIDENCE

IV.

New quantitative radiographic parameters for vertical and horizontal instability in acromioclavicular joint dislocations

PURPOSE

The aim of this study was to identify the most accurate and reliable quantitative radiographic parameters for assessing vertical and horizontal instability in different Rockwood grades of acromioclavicular joint (ACJ) separations. Furthermore, the effect of projectional variation on these parameters was investigated in obtaining lateral Alexander view radiographs.

METHODS

A Sawbone model of a scapula with clavicle was mounted on a holding device, and acromioclavicular dislocations as per the Rockwood classification system were simulated with the addition of horizontal posterior displacement. Projectional variations for each injury type were performed by tilting/rotating the Sawbone construct in the coronal, sagittal or axial plane. Radiographic imaging in the form of an anterior-posterior Zanca view and a lateral Alexander view were taken for each injury type and each projectional variation. Five newly defined radiographic parameters for assessing horizontal and vertical displacement as well as commonly used coracoclavicular distance view were measured. Reliability, validity and the effect of projectional variation were investigated for these radiographic measurements.

RESULTS

All radiographic parameters showed excellent intra- and interobserver reliability. The validity was excellent for the acromial centre line to dorsal clavicle (AC-DC) in vertical displacement and for the glenoid centre line to posterior clavicle (GC-PC) in horizontal displacement, whilst the remaining measurements showed moderate validity. For AC-DC and GC-PC, convergent validity expressed strong correlation to the effective distance and discriminant validity demonstrated its ability to differentiate between various grades of ACJ dislocations. The effect of projectional variation increased with the degree of deviation and was maximal (3 mm) for AC-DC in 20° anteverted malpositioning and for GC-PC in 20° retroverted malpositioning.

CONCLUSIONS

AC-DC and the GC-PC are two novel quantitative radiographic parameters of vertical and horizontal instability in ACJ dislocations that demonstrate excellent reliability and validity with reasonable inertness to malpositioning. The use of AC-DC for assessing vertical displacement and GC-PC for assessing horizontal displacement in a single Alexander view is recommended to guide the appropriate management of ACJ dislocations. A better appreciation of the degree of horizontal instability, especially in lower Rockwood grades (II, III) of ACJ dislocations, may improve management of these controversial injuries.