Ganderup T, Jensen C, Holsgaard-Larsen A, Thorlund JB. Recovery of lower extremity muscle strength and functional performance in middle-aged patients undergoing arthroscopic partial menisectomy. Knee Surg Sports Traumatol Arthrosc, 2017, 25:347-354.
This article documents the recovery of muscles strength and functional performance in middle-aged patients before and after partial menisectomy. Over a 2–year period, 23 patients who underwent an arthroscopic partial menisectomy were tested 2 weeks before surgery and then 3 months and 12 months after surgery. Isometric muscle strength data was acquired from the knee flexors, knee extensors, and hip abductors. The time taken to generate the maximum force was used to calculate rate of force development. In addition, 2 functional tests were also measured: single leg squat for 30 seconds and maximum forward hop for distance.
The results showed pre-operative deficits in knee extensor force and rate of development. There were also statistical differences between the injured and non-injured leg for the single leg squat and hop-for-distance tests. The percentage deficits for the 4 measures ranged from 12% to 19%. At 3 months post-op, the side-to-side deficits remained, and the hip abductors muscles and knee flexor muscles also showed at statistical difference. At 12 months all of the differences in the data had resolved. These results support previous studies that show substantial deficits post-operatively that resolve anywhere from 12 to 48 months after surgery.
Why does this research matter for function? One reason is that it demonstrates functional deficits following a surgical procedure that some consider “benign” and not requiring post-op training. Another reason is that the authors calculated the of force development. This measure has functional consequences because muscle force that takes a long time to develop may not be a viable resource for most activities. Third, the dependent variables included 2 functional tests: single leg squat for 30 seconds, and the hop-for-distance. One could argue that other tests might be more appropriate, but certainly looking at some measures of how the muscles strength resources are utilized is essential for movement practitioners.
All of us in the movement industry are challenged to determine when patients / clients are able to return to sports / activities that caused the injury. Time since injury / surgery has not been an effective criteria because it does not take into consideration any individual differences. Return from knee injury is particularly difficult to gauge due to the influence of the hip, foot, and other regions of the kinematic chain. Nor will isolated tests of the foot or hip provide the desired information. It is only when functional tests, that involve the entire body, are designed to replicate the authentic stresses to the knee that there can be any confidence that the client is ready to return.
At Gray Institute®, practitioners of Applied Functional Science® are taught to take advantage of a sequence of body movements called the “36-360” test. This test combines 36 jumps or hops with 90 degrees of rotation to produce a 360 degree body rotation (and knee stresses) in both directions. When the hop test is performed for 36 consecutive movements on one leg, it can be used to compare one leg to the other (as was done in this research study). The “36-360” can be used to measure total horizontal distance covered, while the time to complete the rotational sequence is documented. Percentage deficits between sides can be calculated to document residual deficits or readiness for return.
The “36-360” creates the three-dimensional stresses to the knee found in dynamic functional activities. Because it places a high demand on the neuro-musculo-skeletal resources of the body, it is only used for a return-to-play test when the patient / client has demonstrated the ability to hop on one leg in all directions. However, if the patient / client has been progressed through the component movements of the “36-360,” it provides a movement challenge that provides the patient / client and the movement practitioner with an objective measure of function.