Exercise Prehabilitation Before ACL Reconstruction

Key Takeaways

• Both groups improved, with guided prehabilitation showing greater KOOS improvement; in the overall mixed-model analysis, KOOS group-by-time interaction terms reached significance at the surgery day and 60 days postoperatively.
• Most secondary measures were similar between groups, with isolated interval-specific differences in Y-Balance and calf raise performance.
• No serious adverse events were reported, while dropout was substantial and the investigators advised cautious interpretation because the effects were small.

Guided prehabilitation was associated with greater improvement in perceived knee function than brochure-based home training before ACL reconstruction. In the overall mixed-model analysis, a KOOS group-by-time interaction reached p=0.039 by the surgery day and again 60 days later. In a single-blinded randomized trial involving people scheduled for reconstruction after unilateral ACL rupture, both groups improved over time. The patient-reported primary outcome favored guided training, and the trial compared guided center-based prehabilitation with structured self-administered home exercise.

This monocentric, prospective randomized controlled trial used 1:1 computer-generated block randomization with sealed-envelope allocation. It enrolled 114 participants aged 16 to 60 years with unilateral complete primary ACL rupture confirmed by MRI and clinical examination, with mean age 31.03 years, SD 10.30, and 53% female. All were scheduled for arthroscopically assisted anatomic reconstruction using hamstring or quadriceps tendon autograft. Guided prehabilitation was tailored, adaptive, structured, and criteria-based, delivered in a rehabilitation center twice weekly for 60 minutes plus weekly home exercise, while the comparator used a six-exercise brochure three times weekly. Training began at the earliest feasible date and lasted at least three weeks. KOOS sum score was the prespecified primary outcome, with range of motion, strength, functional asymmetries, hopping, ACL-RSI, and Tegner score as secondary domains.

Both groups improved before surgery on the KOOS sum score, although the guided group started from a lower baseline. The guided group moved from 46.04 at baseline, with a 95% CI of 45.07 to 47.02, to 58.52 before reconstruction, with a 95% CI of 57.51 to 59.54. The comparator group moved from 51.01, with a 95% CI of 50.10 to 51.92, to 59.18, with a 95% CI of 58.40 to 59.96. In the prespecified pre-surgery mixed model, there were no significant group, time, or group-by-time effects; in the overall mixed-model analysis, the group-by-time interaction was significant for change to the surgery day and to 60 days postoperatively, both at p=0.039. The between-group difference centered on patient-reported knee function and was modest in size.

Most secondary outcomes did not show significant between-group effects across follow-up. There were no significant effects for extension deficit, flexion deficit, ACL-RSI, counter movement jump, and isokinetic testing. Two isolated interval-specific findings emerged within that broader neutral pattern. The calf raise test showed a group-by-time effect favoring the comparator from time point 2 to 7, with p=0.022, while the Y-Balance test favored the intervention from time point 2 to 6, with p=0.046. The objective secondary profile was otherwise broadly similar across groups.

No serious adverse events were reported during follow-up through 180 days after surgery. Meniscus repair surgery led to exclusion in seven participants, acute infections affected three, one participant fell on stairs, and pain-related issues prevented completion of some assessments. Overall, 58 participants discontinued the intervention or dropped out, and travel burden was described as one implementation challenge. Assessments occurred at hospital anamnesis, one to seven days preoperatively, the surgery day, and 30, 60, 90, and 180 days postoperatively. The investigators noted small effects, baseline KOOS differences, difficulty separating training effects from increased clinical contact, and the need for cautious interpretation with further research.