Return to sport after surgical treatment for high-grade (Rockwood III–VI) acromioclavicular dislocation

Acromioclavicular (AC) joint injuries are common in young athletes with an incidence of 9.2 per 1000 person-years [27]. The incidence of AC injuries is higher in contact sports and is highest in adults in their 20s [21, 31]. Full recovery with return to pre-injury level of sports and minimal time lost to injury is essential in the treatment of these injuries.

The Rockwood classification is most commonly used for classifying AC joint injuries according to the severity [31]. Most type I and II dislocations are treated conservatively. For type IV to VI AC joint dislocations, surgical treatment generally is the intervention of choice [21, 29, 31]. The optimal management of type III AC joint dislocations remains controversial. A trend is set toward initial non-surgical treatment, unless non-surgical treatment fails in patients with persistent pain or the inability to return to sport or work [21, 29, 31].

Many surgical techniques have been described for the repair of AC joint dislocations [2, 21]. When evaluating surgical treatment, existing literature mainly measures functionality with outcome scores or self-reported outcome measures. Limited literature exists about the rate of return to sport in this population. However, return to sport has been found to be a good indicator of success after treatment for injuries to the musculoskeletal body [10, 14, 17, 22]. Analyzing the rate of return to sport could provide surgeons and patients with relevant outcome information to optimize shared decision making. The purpose of this systematic review is to assess the rate of return to sport after surgical intervention in high-grade AC dislocation (Rockwood III–VI), to help surgeons address patient expectations. In contrast to the existing literature on this topic, the present review aims to combine outcomes of sports-practicing patients of studies with larger sample sizes and more recent studies with higher levels of evidence.

To conduct this systematic review, the PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) were followed [23].

After removal of duplicates, our initial search yielded 689 articles (370 from PubMed/MEDLINE, 283 from Embase, 36 from Cochrane) (see Fig. 1). Sixty-five articles were selected for full review after screening through titles and abstracts. Eleven articles met the inclusion criteria and were suitable for data extraction. By screening through the reference lists, one additional article was found to be suitable for inclusion in the review [3]. Of the 12 included studies, there was 1 randomized controlled trial (RCT) (level I), 1 prospective comparative study (level II), 4 retrospective comparative studies (level IV) and 6 retrospective case series (level IV). The median MINORS score for the comparative studies was 16.5/24 (range 16–23) and the median MINORS score for the non-comparative studies was 10/16 (range 8–10). Areas of improvement for most studies according to the MINORS were prospective data collection, unbiased assessment of the study endpoint and the prospective calculation of the study size. The RCT was not blinded for patients, personnel and outcome assessment, thereby at risk for detection bias and performance bias. The loss to follow-up was 18%, increasing the risk of attrition bias. Due to the high variety of the different types of sports, level of sports and the surgical techniques, in addition to the methodological heterogeneity and retrospective nature of most study designs, data were not pooled in an official meta-analysis.

Among all included studies, 498 patients underwent surgery for AC dislocation. Baseline characteristics could not be stratified for athletes since many studies included mixed populations. There were 97 patients diagnosed with Tossy III, 93 patients with Rockwood III, 100 patients with Rockwood IV, 208 with Rockwood V and none with Rockwood VI. The weighted mean age was 34 years (range 28–46) with 87% males. The weighted mean follow-up was 34 months (range 22–48). Of all patients, 462 were athletes practicing all levels of sports, ranging from recreational to professional sports. The five most common sports practiced were mountain biking (13%), rugby (10%), soccer (9%), cycling (9%) and fitness (9%) (see Fig. 2).

Most studies used techniques focused on the fixation of the coracoclavicular (CC) ligaments (see Table 1). Older studies most commonly performed an open modified Weaver–Dunn technique or Kirschner wires with additional CC fixation. In more recent studies, open techniques with cortical buttons or AC- and CC-fixation with an allo- or autograft were most commonly used. Three studies performed an arthroscopic technique, all using double cortical button techniques. Due to the wide variety of different surgical techniques, an additional analysis on the return to sport for each technique was not feasible.

For the postoperative care, all studies started with a period of immobilization, ranging from 2 to 6 weeks, followed by either physical therapy or exercises focusing on passive and active range of motion (ROM) (see Table 2).

The most important finding of the present study was a very high (94%) overall rate of return to sport in patients surgically treated for Rockwood III–VI AC dislocation. Additionally, many patients (84%) returned to their pre-injury level of sports. The rate of return to sport in patients surgically treated for high-grade AC dislocation is superior to that of patients surgically treated for rotator cuff repair and arthroscopic Bankart repair (81–85%) [14, 22].

Although this outcome is promising, it must be noted that 10 of 12 studies are level IV, of which the majority are non-comparative studies. In this review, only one randomized study could be included. The RCT of Muller et al. [24] showed that, at 24 months, 100% of patients treated with arthroscopically assisted double-suture-buttons participated in sports compared to 93% of patients treated with a clavicular hook plate.

A subgroup analysis on the rate of return to sport for different types of sports was not feasible. The study of Porschke et al. [30] compared sports activity for overhead athletes versus non-overhead athletes. Overhead athletes needed to change sport activity significantly more often (54% vs 12%; p = 0.011) and 27% had to reduce their sports level to low-demanding sports, while none of the non-overhead athletes lowered their level (p = 0.029). Muller et al. [24] found that overhead athletes had more benefit from a double-suture-button technique than collision athletes and suggested non-anatomic clavicle hookplate as a good alternative for the collision athletes.

The rates of return to sport for Rockwood III and V dislocations were similar. However, there were no comparative studies determining the return to sport outcomes for the different Rockwood subtypes. In addition, not all patients could be included in the Rockwood subgroup analysis since some authors used the Tossy classification, in which Tossy type III corresponds to Rockwood types III to VI. Notable is that the rate of return to sport in Rockwood IV dislocations was found to be lower, although this is mainly based on one study [39] analyzing 78 out of 83 patients with Rockwood IV dislocation included in this analysis. This study found a lower rate of return to former sports, especially among patients treated by a single cortical button technique. However, no data was presented on the possibility that patients practiced other sports at follow-up.

The surgical techniques for AC dislocation varied greatly among the included studies. A subgroup analysis was not feasible. A recent review of Gowd et al. [7] showed, although there is a trend toward minimally invasive procedures, there are no differences in loss of reduction, complication rate and revision rate between open and arthroscopic AC joint reconstruction. Considering return to sport outcomes, the RCT by Muller et al. [24] showed that patients treated arthroscopically by double cortical buttons had a superior level of performance in shoulder sport, close to the level of performance in healthy athletes, compared to patients treated by a hookplate.

Recently, a review on the return to sport after surgical management for AC dislocation was published by Kay et al. [13]. Five out of 12 studies included in the present review were also reviewed by Kay et al.; however, the present review included 7 additional studies reporting on return to sport outcomes after high-grade AC dislocation, one of which was an RCT. In contrast to Kay et al., we excluded three studies [4, 11, 37] due to lack of data on the practicing of sports pre-injury and four studies due to a sample size of less than 20 athletes [1, 6, 28, 36]. Another methodological difference was the approach to non-stratified data on mixed populations. The present review only combined patient outcomes from different studies when data on athletes were stratified, for instance in the analysis of functional outcome measures, while Kay et al. combined patient outcomes from all studies reporting on these outcomes, including studies with mixed populations. In addition, Kay et al. combined return to sport outcomes of acute versus chronic surgery although the cut-off intervals between studies were very different. No conclusion could be drawn on the rate of return to sport for acute versus chronic AC dislocation because of the many different definitions used for these injuries. For future research, it is important to work with one definition and one cut-off interval to be able to compare acute and chronic surgeries in different studies.

The present review was limited by the overall low level of evidence provided by the many level IV studies. As a consequence, no robust conclusions can be drawn on return to sport outcomes for different subgroups comparing surgical techniques, acute versus chronic surgery, types of sports and Rockwood subtypes. In addition, the rates of return to sport were mostly secondary outcomes in these studies, with insufficient attention paid to the many aspects of the return to sport. This may lead to publication bias when only high rates of return to sport are reported.

In this review, no comparison was made between conservative and surgical treatment for patients with high-grade AC dislocation. Non-operative treatment for high-grade AC dislocation is being studied more extensively since functional outcome may be non-inferior to surgery. A recent meta-analysis comparing surgical and conservative treatments of Rockwood III AC dislocation showed no significant differences in terms of functional outcome scores [34]. Similar findings are presented for Rockwood IV and V AC dislocations [12, 16, 25, 26]. Murray et al. [25], comparing open reduction and tunneled suspensory device with non-operative treatment in Rockwood III and V, states that non-operatively managed patient generally recover faster, although a substantial part of remain dissatisfied and require delayed surgical reconstruction.

The outcomes of this review may help surgeons in addressing patient expectations in a sporting population facing surgery for AC dislocation. Patients can now be properly informed on the rate of return to sport, time to return to sport and the patient satisfaction with the results. Still, surgeons need to consider conservative therapy, especially in Rockwood III, since non-surgical treatment can result in similar functional outcome. For future research, high-quality comparative studies are needed to provide adequate data for subgroup analysis on functional and sport outcomes, for both conservative and surgical treatment. When assessing return to sport outcomes, it is imperative to incorporate aspects of sports activity, frequency and intensity.