Loss of knee extension is very common following a knee surgery or a knee injury. Full restoration of knee extension is vital to patient outcomes. A study by Shelbiurne and Gray in AJSM 2009 showed that loss of extension following ACL reconstruction led to oseteoarthritis. It showed that loss of full knee extension decreases the patients satisfaction outcomes. If full knee extension is not restored via physical therapy then the patient will demonstrate functional deviations and gait abnormalities. Physical therapy is essential in restoring knee extension following surgery or injury and consists of 2 stages, passive and active knee extension. The patient must have full passive motion before they can have full active motion, so it is essential to start passive knee extension immediately following surgery. Passive knee extension is the ability of an outside force to stretch the knee through full range of motion. Three tissues primarily limit this motion; the hamstring muscle, the gastroc muscle, and the posterior joint capsule. Physical therapy will consist of dry needling, cupping, and soft tissue mobilization (massage) to loosen the muscles up in order to improve passive knee extension. The joint capsule responds best to low load, long duration stretching so it is recommended to perform 4 sets of 15 min passive stretching into extension in order to achieve full range of motion. The patella (knee cap) can also limit both passive and active knee extension if it does not move freely. In a mobile knee it must glide superiorly in order for the knee to achieve full extension and to allow the quads to fully engage. Your physical therapist will perform superior patellar mobilizations in order to restore full patella motion. Once passive knee extension is achieved, the focus shifts to aggressive facilitation and strengthening of the quad muscle in order to achieve full active knee extension. There are lots of different exercises to facilitate and strengthen the quads but I find that many Physical Therapists skip over the basics and get to the “fun” exercises too quickly. There is a time to push the “functional” exercises like skater squats, bulgarian split squats, lunges, etc but if you don’t master the basics you will regress, evidenced by swelling and prolonged pain. I see it time and time again the PTs skip over the basics just to progress to functional exercises quickly, but the patient continues to struggle with swelling and pain for longer than they should and it really slows their progress. At physioFit we emphasize the basics then move on to the fun exercises! It is vital to establish volitional control of the quads at full terminal knee extension. We use neuromuscular re-education (NMES) to facilitate a good quad contraction. Numerous studies, including Labanca et al, 2018 show NMES with exercise increase quad strength greater than exercise alone. The pictures below show our patient working on quad facilitation and strengthening using the NMES device. We utilize this unit because it has a switch that the patient can press to activate the quads which allows the patient to be in full control of their quad contraction. Once we establish good volitional control of the quads we progress to the more functional exercises but we master the basics first! If you or anybody you know has knee pain reach out to us and we would love to work with you!!
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