Modified Weaver-Dunn Procedure for Type 3 Acromioclavicular Joint Dislocation: Functional and Radiological Outcomes

Abstract

Background: Controversy surrounds the indication for treatment of type 3 acromioclavicular joint dislocation, and the optimal reconstructive technique has not yet been defined. Since the first description of the Weaver-Dunn procedure, several studies have described the clinical and radiological results that can be expected postoperatively; however, few studies have evaluated the outcomes of this technique for chronic type 3 acromioclavicular joint dislocation.

Purpose/hypothesis: The purpose of this study was to evaluate the functional and radiographic mid- to long-term outcomes of a modified Weaver-Dunn procedure for chronic Rockwood type 3 acromioclavicular joint dislocation. We hypothesized that (1) functional outcomes comparable with sex- and age-matched healthy individuals could be achieved with the modified Weaver-Dunn procedure and (2) joint stability could be restored after surgery.

Study design: Case series; Level of evidence, 4.

Methods: Out of 30 patients who sustained a chronic type 3 acromioclavicular joint dislocation, 27 had a minimum 12-month follow-up and were included in the study. All patients underwent a modified Weaver-Dunn procedure. The Constant-Murley score was used to assess patient postoperative function. Subjective evaluation of patient satisfaction with surgery was also recorded. Radiological assessment was performed postoperatively to evaluate superoinferior and anteroposterior joint stability.

Results: After a mean follow-up period of 51.6 months, the mean Constant-Murley score was 90.1, which was 97.2% that of a group of sex- and age-matched healthy individuals. In the multivariate analysis, higher Constant-Murley score was associated with male sex (β = 0.385; P = .043) and higher subjective satisfaction scale (β = 0.528; P = .003). All patients returned to their previous work and sport activity levels having high satisfaction with surgery. Successful vertical acromioclavicular joint reduction was obtained in all but 1 patient; however, horizontal joint stability was not completely restored with the modified Weaver-Dunn procedure. No intraoperative complications occurred, and the postoperative complication rate was 7.4%.

Conclusion: In patients with chronic type 3 acromioclavicular joint dislocation, the modified Weaver-Dunn procedure is an effective technique to restore vertical but not horizontal joint stability 4 years after surgery. High levels of satisfaction with surgery and functional outcomes comparable with sex- and age-matched healthy individuals can be achieved.

Keywords: Constant-Murley score; Rockwood type 3 dislocation; Weaver-Dunn; chronic acromioclavicular joint dislocation; outcome predictors; radiological assessment of acromioclavicular joint stability.

Figure 1.

Schematic drawing of (A) a grade 3 acromioclavicular joint dislocation treated with a modified Weaver-Dunn procedure. (B) The lateral end of the clavicle is resected and the coracoacromial ligament is harvested with a tricortical bone block from the acromion. (C) The coracoacromial ligament, together with the acromial bone block, is prepared with 2 nonabsorbable braided sutures passed through drill holes performed at the lateral end of the clavicle. The clavicle is reduced, and a surgical tape is passed around the clavicle and coracoid process. (D) Thereafter, the acromial bone block together with the coracoacromial ligament is secured to the clavicle.

Figure 2.

Measurement of coracoclavicular (CC) ratio on Zanca view. The CC ratio is the coracoclavicular distance between the cranial rim of the coracoid and the caudal border of the clavicle.

Figure 3.

Measurement of D/A ratio on Zanca view: “A” is the height of the acromion, between its inferior and superior margins. “D” is the distance between the line drawn through the inferior margin of the acromion and a parallel line passing through the lowest and most lateral point of the clavicle.

Figure 4.

Measurement of X/Y ratio on axillary view: “Y” is the distance between a line drawn through the middle of the outer quarter of the clavicle along the longitudinal axis and a parallel line drawn through the most anterior and lateral margin of the clavicle. “X” is the distance between a third line, parallel to the other 2, drawn through the most anterior margin of the acromion and the one passing through the most anterior and lateral margin of the clavicle.