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.

Effect of subacromial erosion shape on rotator cuff and clinical outcomes after hook plate fixation in type 5 acromioclavicular joint dislocations: a retrospective cohort study

Background

Surgical fixation using hook plates is widely used in the treatment of acromioclavicular (AC) joint dislocations. The purpose of this study was to evaluate the incidence and shape of subacromial erosions after removal of the hook plate in type 5 AC joint dislocations. Further, we evaluated the effect of the shape of the subacromial erosion on the rotator cuff.

Methods

We retrospectively reviewed 30 patients who underwent hook plate fixation for type 5 AC joint dislocations at our hospital between December 2010 and December 2018. Patients with a follow-up of at least 1 year were included. Clinical outcomes were assessed using the final follow-up Constant-Murley, Korean Shoulder, and visual analog scores. To ensure that the appropriate reduction was well maintained, the coracoclavicular distances of the injured and contralateral sides were evaluated at the last follow-up. Computed tomography was performed to investigate the presence and shape of the subacromial erosion after hook plate removal at 4 months after surgery. Ultrasonography was performed to investigate the presence of rotator cuff lesions at the last follow-up. Clinical and radiological outcomes were compared between groups divided according to the presence and types of subacromial erosions.

Results

Subacromial erosion was observed in 60% of patients (18/30): 13, 2, and 3 simple groove, cave, and marginal protrusion types, respectively. Four patients showed reduction loss at the final follow-up. There were no significant differences in clinical and radiological outcomes between the groups with and without subacromial erosion. Moreover, there were no significant differences between groups according to the types of subacromial erosion. There were no rotator cuff lesions, such as partial tears, in the injured shoulders.

Conclusions

Hook plate fixation may induce subacromial erosions. However, the subacromial erosions caused by the hook plate did not affect the clinical outcomes of type 5 AC joint dislocations. Moreover, regardless of its shape, the subacromial erosion did not affect the clinical outcomes nor cause rotator cuff lesions after plate removal.

Residual coracoclavicular separation after plate fixation for distal clavicle fractures: comparison between fracture patterns

Background

Plate fixation is an established treatment for Neer type II and V distal clavicle fractures; however, residual coracoclavicular (C-C) separation after osteosynthesis for unstable distal clavicle fractures has rarely been discussed. This study aimed to reveal the extent of postoperative C-C separation after plate fixation for distal clavicle fractures and to evaluate the relationship between residual C-C separation and the risk of postoperative complications.

Methods

We retrospectively reviewed 60 patients with a displaced distal clavicle fracture that was treated with a Scorpion plate without C-C reconstruction and successfully united. Distal clavicle fractures were divided as per the Neer classification into type IIA (12 patients), IIB (36 patients), and V (12 patients) groups. The modified C-C distance ratio at the time of injury and after bone union, and the postoperative complications (plate-related pain, delayed union, infection, and contracture) were compared among the three groups.

Results

The mean postoperative modified C-C distance ratio was 115.0% ± 12.0%; this ratio was significantly larger in the type IIB and V groups than in the type IIA group (P = .021 and P = .006, respectively). However, there was no significant difference in the frequency of postoperative complications among the three groups.

Conclusions

Our study demonstrated that a certain degree of C-C separation remained after plate fixation for Neer type II and V distal clavicle fractures, even when bone union was achieved. The postoperative residual C-C separation was greater for the type IIB and V groups than for the type IIA group; however, this difference may not affect postoperative complications.

The frequency of reduction loss after arthroscopic fixation of acute acromioclavicular dislocations using a double-button device, and its effect on clinical and radiological results

Background

The aim of this study was to investigate the effect of reduction loss of more than 3 mm on clinical and radiological results after at least 2 years of follow-up after arthroscopic fixation of acute acromioclavicular joint dislocations using a double-button device.

Methods

Thirty-six patients who had acute (< 3 weeks old), type III or V acromioclavicular (AC) joint dislocations underwent arthroscopic fixation of the AC joint using a double-button device. Clinical and radiological evaluations were performed at preoperative, postoperative first day, 3 months and last follow-up. When the coracoclavicular (CC) distances of patients at the last follow-up were compared to the early postop CC distances, those with a difference of 3 mm or less were grouped as group A and those with a difference of more than 3 mm were grouped as group B.

Results

There was no statistically significant difference between the groups in terms of age, gender, follow-up time, time from injury to surgery, return to work, and distribution of Rockwood classification. Pre-operative CC distance was reduced from 18.7 ± 3.5 to 8.5 ± 0.6 in the early postoperative period. Anatomic reduction was achieved in all patients compared with the unaffected side (CC distance 8.6 ± 0.7). However, the CC distance increased to 9.9 ± 1.5 at the third-month follow-up and increased to 11 ± 2.7 at the last follow-up. There were no significant Constant score differences between the groups in the preoperative and last follow-up periods (p > 0.05). At the last follow-up, the mean Acromioclavicular Joint Instability (ACJI) score of group A was 84.4 ± 8, whereas it was 68.3 ± 8.3 for group B, and the difference was statistically significant (p < 0.01). Furthermore, the subjective evaluation and aesthetic subjective satisfaction values of group B were lower than group A (p < 0.01).

Conclusions

Reduction loss of more than 3 mm was observed in 25% of patients after arthroscopic fixation of acute acromioclavicular dislocations using a double-button device. Although this loss did not create a statistically significant difference in Constant scores, AC joint-specific tests such as ACJI, subjective evaluation, and aesthetic subjective satisfaction values were significantly impaired.

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

BACKGROUND

The conventional AO hook locking compression plate (LCP) (Synthes, Solothurn, Switzerland) has only three holes for lateral fragments; therefore it is not suitable for use during the fixation of small-comminuted fragments in some cases. Recently, a novel hybrid hook LCP (TDM, Seoul, Korea) was developed to overcome this limitation. Here, we evaluated the clinical and radiologic outcomes of a novel hybrid hook LCP for Neer type V distal clavicle fractures compared to the outcomes of a conventional AO hook plate.

METHODS

Seventy-eight consecutive patients who underwent hook LCP fixation for Neer type V distal clavicle fractures were included. The subjects were divided into 2 groups: the conventional AO hook LCP group and the novel hybrid hook LCP group. For clinical assessments, the American Shoulder and Elbow Surgeons (ASES) score, Korean shoulder score (KSS), and Constant score were recorded. The percentage modified coracoclavicular distance (MCCD %) was used for the evaluation of fracture reduction. Typical reported complications, such as secondary dislocation, implant failure or loosening, peri-implant fracture, acromion osteolysis, postoperative acromioclavicular joint arthrosis, non-union, or delayed union, were also analyzed.

RESULTS

There were no differences in the clinical outcomes (ASES, KSS, and Constant scores) between the two groups. Bone union was achieved in a significantly shorter period in the hybrid hook LCP group (13.6±2.0weeks) than in the AO hook LCP group (17.5±4.8weeks, p<0.001). Consequently, the time to implant removal was also significantly shorter in the hybrid hook LCP group (4.0±0.5months) than in the AO hook LCP group (5.4±1.1months, p<0.001). The MCCD% showed no significant differences between the treatment groups. There was no statistically significant difference in the complication rate between the two groups; however, the hybrid hook LCP fixation resulted in a lower prevalence of hook-related complications.

CONCLUSION

The hybrid hook LCP fixation showed satisfactory clinical and radiologic outcomes in comparison with the AO hook LCP fixation. The hybrid hook LCP is useful for multiple screw fixation of inferior comminuted fragments in Neer type V distal clavicle fractures. The bone union was significantly shorter; thus, the time to implant removal was also significantly shorter.

LEVEL OF EVIDENCE

Level III, Retrospective study.

Comparative analysis of locking plate versus hook plate osteosynthesis of Neer type IIB lateral clavicle fractures

INTRODUCTION

Controversy exists on optimal operative treatment of vertically unstable Neer IIB lateral clavicle fractures. Aim of this study was to analyse and compare clinical and radiological results and complications of locking plate osteosynthesis (LPO) versus hook plate osteosynthesis (HPO) with acromioclavicular joint (ACJ) stabilization. The hypothesis was, that HPO would recreate coracoclavicular stability more effectively and potentially lead to a superior outcome.

METHODS

This retrospective, observational cohort study included 32 patients (19 HPO, 13 LPO) with a mean age of 44.1 ± 14.2 years at surgery. The mean follow-up period was 54.2 months (range 25.2-111.4 months). Besides standard radiography, bilateral coracoclavicular distances were assessed by means of preoperative and follow-up stress radiographs after implant removal. Clinical outcome measures included the Constant score (CS), the Oxford shoulder score (OSS), the subjective shoulder value (SSV) and the Taft score (TS).

RESULTS

Bone union occurred in all but one patient and proved to occur delayed in five patients (15.6%). Radiographical healing required a mean of 4.2 ± 4.0 months irrespective of the type of osteosynthesis. At follow-up, mean coracoclavicular distance was increased by 34% (±36) without significant differences between both groups. HPO patients obtained a significantly lower TS (HPO: 9.5 ± 1.5 points, LPO: 11.1 ± 1.3 points; p = 0.005). Other mean score values did not differ (CS: 90.1 ± 7.4 points, OSS: 43.2 ± 9.2 points, SSV: 91.1 ± 14.7%). Sixteen patients (50.0%) experienced complications. Overall prevalence of complications was significantly higher in the HPO group (p = 0.014).

CONCLUSIONS

Both HPO and LPO were equally effective in relation to restoration of vertical stability, overall functional outcome and fracture consolidation in treatment of Neer IIB fractures. Contrary to our hypothesis, HPO was not associated with superior recreation of the coracoclavicular distance. Considerable drawbacks of HPO were an inferior ACJ-specific outcome (Taft-Score) and a higher overall complication rate. Level of evidence IV.