Paper 59: No Difference in Post-Operative Outcomes for High-Grade Acromioclavicular Joint Surgery Performed Acutely vs Chronically

OBJECTIVES: There have been no large studies that directly compare long term outcomes in patients with Rockwood grade III-V acromioclavicular (AC) joint separations treated with acute vs. chronic repair. Therefore, the purpose of this study was to compare post-operative outcomes between patients who undergo high-grade AC joint surgery acutely (<6 weeks) vs chronically (>6 weeks). METHODS: A list of all AC joint surgery patients from 2010-2019 was obtained from the medical records. Chart review was conducted to determine patient demographics, time from injury to surgery, injury grade, and surgical technique, as well as outcomes and complications of AC joint surgery. Post-operative American Shoulder and Elbow Surgeons (ASES) and Single Assessment Numeric Evaluation (SANE) scores were also collected via RedCap. Patient radiographic outcomes were retrospectively reviewed by reviewing preoperative, immediate postoperative, and follow-up AP views of the operative shoulder and measuring the coracoclavicular (CC) interval distance. Loss of reduction was defined as a follow-up change of greater than 5 mm from the immediate post-operative radiographs measurement. Several multivariate analyses were conducted with post-operative ASES, SANE, and CC distance as the outcomes of interest in order to account for demographic differences between groups. RESULTS: Overall, 225 patients (113 acute, 112 chronic) were included in this study with an average follow-up of 3.5±2.8 years, average age of 40±15 years, and 86% being male. Patients in the acute group underwent surgery 2 ± 1 weeks after initial injury while patients in the chronic group underwent surgery 42 ± 35 weeks after injury. Significant differences in patient age, BMI, injury grade, surgical technique utilized, and pre-operative CC distance were observed between groups (all p<0.05) (Table 1). Rates of revision, loss of reduction, infection, fracture, and total complication rate, as well as post-operative ASES scores did not differ between groups. Patients treated acutely had a lower rate of loss of reduction (1.8mm v. 3.2mm, p=.044), a larger decrease in CC distance at latest follow-up compared to pre- operatively (11.8mm v. 9.0mm, p =.002), and better SANE scores (85.5 v. 75.5, p=.032). All other post- operative outcomes did not differ between groups. After controlling for confounding variables such as age, sex, BMI, injury grade, surgical technique, and time from injury to surgery, multivariate analysis found that female patients had lower ASES scores than male patients, while all other variables did not significantly relate to ASES score, SANE score, or post-operative CC distance (Table 2). CONCLUSIONS: Patients who underwent AC joint surgery acutely (<6 weeks) had similar post-operative outcomes to patients who underwent surgery chronically (>6 weeks) after initial injury. Multivariate analysis found that time from injury to surgery did not affect post-operative ASES scores, SANE scores, or post-operative CC distance.