LUND, Sweden—Nearly all American patients with anterior cruciate ligament (ACL) damage undergo ACL reconstruction surgery, but they would probably regain as much muscle strength and function from physical therapy alone. Data from patients enrolled in the first randomized, controlled trial (RCT) to compare surgical vs. nonsurgical intervention show that at a mean follow-up of 3 years after injury,
  • strength tests were similar,
  • function tests were similar, and
  • only about half of patients in either group had normal knee function.1

“The lack of differences between patients treated with training and surgical reconstruction or training only indicates that reconstructive surgery is not a prerequisite for restoring muscle function.”—Eva Ageberg, PT, PhD
Lead author Eva Ageberg, PT, PhD, commented, “The lack of differences between patients treated with training and surgical reconstruction or training only indicates that reconstructive surgery is not a prerequisite for restoring muscle function.” Dr. Ageberg, who is in the orthopedics department at Lund University Hospital in Lund, Sweden, also pointed out that muscle function remained significantly abnormal in more than one-third of patients, which predicts a higher risk of future knee osteoarthritis (OA) in these patients.

No gain in hop, jump, symmetry, or strength after knee ACL reconstruction

This study was an add-on examination for patients enrolled in the first randomized, controlled trial to compare physical training with surgical reconstruction: the KANON (Knee Anterior cruciate ligament, NON-surgical versus surgical treatment) study. Dr. Ageberg emphasized that this was not part of the RCT, outcomes of which will be reported separately.

The muscle strength and function study included 54 patients (15 women, 39 men), 36 of whom had been randomized to training plus surgical reconstruction, and 18 of whom had been randomized to training alone. 20 patients had reconstructive surgery with patella tendon graft and 16 had surgery with hamstring tendon graft.

All patients in both groups followed a moderately aggressive, physical therapist-supervised training program for at least 4 months. The protocol included exercises and set goals for range of motion, muscle function, and functional performance.

The researchers used a battery of 3 hop tests to measure functional performance and 3 muscle power tests to measure lower extremity muscle strength. Dr. Ageberg said that all patients wore shorts, T-shirts, sneakers, and medical stockings covering both knees to disguise possible scars from surgery and maintain investigator blinding. The hop tests included vertical jump, one-leg hop for distance, and side hop. The strength tests measured quadriceps and hamstring muscle power during knee extension and knee flexion, as well as lower extremity muscle power during leg press.

“The principal findings of this study were that there were no differences between the surgical and the nonsurgical treatment groups in muscle strength or functional performance between 2 and 5 years after injury; that approximately two-thirds of the patients had recovered normal muscle function in the single tests; and that only approximately half of the patients had recovered normal function for the test batteries,” Dr. Ageberg reported.

Dr. Ageberg noted that the primary outcome, the Limb Symmetry Index (LSI) in the hop and strength tests were high in both groups, “indicating good muscle function regardless of whether or not patients underwent surgical reconstruction.”

Study limitation: 41% of patients not included in follow-up assessment

The investigators wrote that the study's major strength is that all of the patients were from an RCT on training and surgery versus training only, but its major limitation is that 41% of the patients contacted for the follow-up did not attend the assessment.

However, the nonattendees were younger, had a higher activity level, and had better subjective scores than the attendees, and 61% had been treated with training only. This suggests that their participation would likely have  strengthened the study's main conclusion: ACL reconstruction adds little to restoring muscle function beyond the benefits of training alone.

Reference

1. Ageberg E, et al. Muscle strength and functional performance in patients with anterior cruciate ligament injury treated with training and surgical reconstruction or training only: A two- to five-year follow-up.  Arthritis Care & Research 2008;59:1773-1779.