Reviewed by Tyler Tice, PT, DPT, OCS, ATC
Introduction:
Arthroscopic partial meniscectomies (APM) are a minimally invasive surgical procedure that is used to reduce or even eliminate the symptoms associated with a meniscus injury. It is common for patients to return to normal recreational activities with very little supervised rehabilitation through physical therapy. However, it is becoming increasingly clear within current evidence that patients who undergo meniscectomy surgeries demonstrate significant quadriceps atrophy, quadriceps inhibition, and strength. Although muscular strength and hypertrophy are common goals of physical therapy after APM, the rate of torque development (RTD) is a metric that is often overlooked in its significance for performing recreational activities and as result many patients maintain a low RTD even 5 weeks post-op. The importance in RTD after APM has not been widely studied and was theorized by the researchers to be heavily linked to patient reported outcomes after surgery because of its role in performance of recreational activity.
Methods:
The study included 20 participants undergoing APM. Participants were excluded from the trial if they had a current or recent other knee ligament injury, recent lower extremity fracture, BMI of 40kg/m2, or inability to perform an MRI. Each participant underwent MRI imaging to determine muscle volume, EMG analysis of quadricep activation, muscle contraction speed testing, knee extension maximal voluntary isometric contraction testing, RTD testing, and voluntary activation completeness.
Conclusions of the Study:
Researchers concluded that there were several factors that contributed to the RTD deficits seen after APM. Maximum strength and the time it takes for the participant to reach maximal strength accounted for roughly 10-15% of the between limb deficits seen in patients after APM. Deficits in neuromuscular control of the quadriceps were a predicted contributor to the slowed RTD seen in APM patients. It was also noted that although a participant may be able to restore quadricep muscle volume and absolute strength after surgery, it does not correlate with a return to previous RTD and deficits in RTD were similar at 2 weeks and 5 weeks post-op to pre-surgical measures. Participants with greater side-to-side differences were associated with worse patient related outcomes, however due to the smaller size of this study and limited scope of time utilized to see patient outcomes these results should be interpreted with caution until a larger study is conducted with the same results.
Clinical Implications:
Quadriceps strength and knee extension range of motion are key aspects of rehab for most post-op knee related patients. However, what is often not considered is the RTD which can be significantly lacking after APM and potentially other arthroscopic surgical interventions. Normal recreational and activities of daily living require a great deal of rapid muscle activation to perform them well. Therefore, it is advised based on the evidence in this study to incorporate rapid knee extension based movement into patient’s rehabilitation program whenever it is appropriate in order to improve RTD. Incorporating knee extension focused power, plyometric, and agility movements, while also promoting quadriceps absolute strength and hypertrophy, could improve patient related outcomes within the first 5 weeks post-op as long as the exercise selection is appropriate for the patient’s goals. However, further investigation is needed in order to determine if there are long term deficits in RTD in APM and other arthroscopic surgical patients that can be addressed by incorporating power, agility, and plyometric training earlier in rehabilitation.
Reference
Cobian, D. G., Koch, C. M., Amendola, A., & Williams, G. N. (2017). Knee extensor rate of torque development before and after arthroscopic partial meniscectomy, with analysis of neuromuscular mechanisms. Journal of Orthopaedic & Sports Physical Therapy, 47(12), 945–956. https://doi.org/10.2519/jospt.2017.7310