Pain after out-patient vs. in-patient ACL reconstruction: French prospective study of 1076 patients.

BACKGROUND: Anterior cruciate ligament (ACL) repair is increasingly performed on an out-patient basis. In France, however, concern about post-operative pain remains a strong barrier to out-patient ACL repair. The primary objective of this study was to compare post-operative pain after ACL repair as out-patient versus in-patient surgery. The secondary objectives were to assess the time-course of post-operative pain and to identify factors associated with pain intensity.

MATERIAL AND METHODS: A multicentre, prospective, comparative, non-randomised study was conducted in France for the French Society for Arthroscopy (SFA) symposium. Patients who underwent primary ACL repair between January 2014 and March 2015 were included if they were eligible for out-patient surgery. The choice between out-patient and in-patient surgery was based on organisational and logistical considerations. Pain intensity was self-evaluated by the patients using a visual analogue scale (VAS), pre-operatively then in the evening after surgery, during the night after surgery, and 1, 3, and 5 days after surgery. The patients performed the evaluations at home using websurvey.fr® software. Demographic data, the characteristics of the surgical procedure, and the IKDC and Lysholm scores before and after surgery were collected.

RESULTS: Of the 1076 patients included in the study, 680 had out-patient surgery and 396 in-patient surgery. Mean age was 30±9 years. The two groups were comparable at baseline. Pain intensity was not significantly different between the two groups at any of the measurement time points. Pain intensity showed a peak on post-operative day 1 that was similar in the two groups. The initial post-operative pain intensity score predicted subsequent pain intensity: patients with VAS scores <2 on the day of surgery also had low pain scores after surgery. In both groups, factors associated with greater pain intensity were age <25 years, high pre-operative pain score, and surgery performed after noon. Neither surgical technique nor concomitant lesions and methods used to treat them were associated with pain intensity. Risk factors for severe post-operative pain (VAS score >7) in the out-patient group were younger age, female gender, pre-operative VAS score >3, and tourniquet time >50minutes.

CONCLUSION: Pain intensity is similar after out-patient and in-patient ACL repair. Concern about pain should not be a barrier to performing ACL repair on an out-patient basis. Our data on the time-course of the pain and factors associated with greater pain intensity should prove useful for improving patient management after ACL repair.

LEVEL OF EVIDENCE: Level III, case-control study.