Data presented at the 2012 annual meeting of the Orthopaedic Trauma Association indicate that surgical repair with hook plate fixation is not superior to nonsurgical treatment for acute dislocation of the acromioclavicular (AC) joint (Fig. 1). The study also found no clear evidence that hook plate fixation improves short-term outcomes for complete AC joint dislocations.

Although the current literature suggests no advantage to surgical intervention, according to presenter Michael D. McKee, MD, of St. Michael’s Hospital, Toronto, prior trials comparing the two treatment methods used outdated surgical techniques and surgeon-based or radiographic outcome measures. Dr. McKee and his fellow researchers sought to evaluate surgical versus nonsurgical treatment of acute AC joint dislocations using modern surgical fixation and patient-based outcome measures.

Prospective, randomized clinical trial
The researchers performed a prospective, multicenter, randomized trial comparing surgical repair with hook plate fixation to nonsurgical treatment for acute complete dislocations (grades III, IV, V) of the AC joint in patients aged 16 to 60 years. Of the 83 patients, 40 (36 males, 4 females; mean age: 38 years) were randomized to surgical repair with hook plate fixation; 43 (42 males, 1 female; mean age: 37 years) were randomized to nonsurgical treatment with a sling. Both groups had similar demographics and no significant differences in mechanisms of injury or degree of initial displacement.

Patients in the surgical cohort underwent hook plate fixation within 21 days of the injury and began performing active and passive exercises at 2 weeks postoperatively. Resistance exercises were implemented at 6 weeks and patients were allowed to return to full activity at 3 months postoperatively. The mean time for removal of the plate in 32 patients was 8 months. The plates were well tolerated and therefore not removed in the remaining 8 patients.

“We reduced the dislocation with a hook plate, in general, without any other augmentation devices, although our surgical protocol allowed it,” said Dr. McKee.

Patients in the nonsurgical cohort wore a sling for 4 weeks at which time they began active and passive exercises, followed by resistance and strengthening exercises at 6 weeks postinjury. Pendulum exercises were implemented per the attending surgeon’s discretion.

No significant differences found
The researchers compared results for the two cohorts at 6 weeks and at 3-, 6-, 12-, and 24-month follow-up using the following outcome measures:

• Disabilities of the Arm, Shoulder and Hand (DASH) score
• Constant Shoulder score
• Short Form-36
• clinical assessment
• standardized radiographs

The primary outcome measure was the DASH score at 1 year.

“We performed comprehensive follow-ups on both groups and were very careful to standardize the radiographs in terms of the position of the patient (standing, arms at side, no sling) and the views (bilateral AC joints, AP view with 10-degree cephalic tilt, axillary view of the affected shoulder),” said Dr. McKee.

The researchers found that mean DASH scores were significantly better in the nonsurgical cohort at 6 weeks and 3 months (32 and 16, respectively), compared to the surgical cohort (46 and 29). However, they found no significant differences in DASH scores between the two groups at 6 months, 1 year, or 2 years. Similarly, there were no significant differences in Constant score values between the two groups (Table 1).

Radiographic alignment was much better in the surgical group than in the nonsurgical group. At 1 year, 8 percent of surgical patients had a subluxated joint, compared to 89 percent of nonsurgical patients (P = 0.0001).

Complications in the nonsurgical group included soft-tissue complications (n = 2) and heterotopic ossification (n = 3); 8 patients were unhappy with the appearance of the shoulder. Complications in the surgical group included two acromial erosions and two plate failures. “In retrospect, all four surgical complications were due to over reduction of the joint and we have since refined our techniques and implants,” said Dr. McKee.

The authors noted that they were unable to demonstrate a difference in the two groups at early follow up, due primarily to the rapid improvement and good outcomes in the nonsurgical patients.

“We found that shoulder function and clinical outcomes were consistently good in both groups, with a mean Constant score of greater than 90 and a mean DASH score of approximately 9 in both groups at 1 year,” said Dr. McKee.

The researchers concluded that although hook plate fixation is a consistent surgical technique with a low complication rate that reliably restores AC joint alignment, it is not superior to nonsurgical treatment in acute AC joint dislocations. They also found no clear evidence that surgical treatment with currently available implants improves short-term outcome for complete AC joint dislocations.

Dr. McKee added, “Unfortunately, we have not been able to reliably identify the small subgroup of patients who are unhappy following nonsurgical care of this injury.”

Maureen Leahy is assistant managing editor of AAOS Now. She can be reached at leahy@aaos.org

Dr. McKee’s coauthors of “A Multicenter Randomized Clinical Trial of Nonoperative versus Operative Treatment of Acute Acromioclavicular Joint Dislocation,” are Stéphane Pelet, MD, PhD; Karine Sinclair, MD; Luc Bédard, MD; Jean Lamontagne, MD; Emil H. Schemitsch, MD; Jeremy A. Hall, MD; Milena R. Vicente, RN; Robert G. McCormack, MD; Dominique Rouleau, MD; Pierre Guy, MD; Edward J. Harvey, MD; Andrew Furey, MD; Christian Veillette, MD; and Terry Axelrod, MD.

Disclosures: Dr. McKee—Stryker; Synthes; Zimmer; Wright Medical Technology, Inc.; Wolters Kluwer Health: Lippincott Williams & Wilkins; Journal of Orthopaedics and Traumatology (JOT); American Shoulder and Elbow Surgeons; Orthopaedic Trauma Association (OTA); Canadian Orthopaedic Association (COA); Dr. Pelet—Arthrex Inc.; Amgen; Astra Zeneca; Président Comite de DPC AOQ; Dr. Lamontagne—Zimmer; Synthes; Dr. Schemitsch—Stryker; Amgen Co.; Smith & Nephew; Wright Medical Technology, Inc.; Kuros; Zimmer; Synthes; Saunders/Mosby-Elsevier; JOT; OTA; COA; Dr. Hall —Stryker; Zimmer; Pfizer; Synthes; Smith & Nephew; Amgen Co; Biomimetic; Dr. McCormack— Stryker; Synthes; COA; Dr. Rouleau—Smith & Nephew; DePuy, A Johnson & Johnson Co.; KCI; Stryker; Synthes; Zimmer; Dr. Guy—Stryker; Traumis; Synthes; DePuy, A Johnson & Johnson Co.; Dr. Harvey—Synthes; Stryker; Smith & Nephew; Zimmer; Canadian Journal Of Surgery; JOT; OTA; COA; Dr. Veillette—Biomet; Smith & Nephew; Clinical Orthopaedics and Related Research; COA; Ms. Vicente and Dr. Furey—no conflicts; Drs. Sinclair, Bédard, and Axelrod—no information available.

Bottom Line

• Although AC joint dislocation is a common injury, the optimal treatment remains unclear.
• This study was the first prospective randomized clinical trial comparing surgical and nonsurgical treatment of these injuries using modern surgical fixation and patient-based outcome measures.
• Results indicated that surgical repair with hook plate fixation is not superior to nonsurgical treatment for acute dislocation of the AC joint.
• The study also found no clear evidence that hook plate fixation improves short-term outcomes for complete AC joint dislocations.