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knee rehabilitation

Knee rehabilitation

Athletes frequently return from one injury only to fall victim to another – a source of frustration for both athlete and therapist. A prime example is an overuse injury that develops as an athlete increases their training load after a period of rehabilitating an acute injury.

The consideration of proprioception retraining is especially important to prevent overuse problems after acute injury (see Mark Alexander’s article on proprioceptive deficits and injury in SIB 36). Most therapists and conditioning experts now incorporate proprioception retraining within rehab – indeed, they would be negligent not to. However, I believe most rehab programmes for athletes are insufficiently targeted to address specific muscle groups that are pain inhibited and weakened through disuse. When the acute injury is physiologically ready for a return to training, these muscle groups are then expected to perform at the same level as before, despite weeks or even months of disuse and inhibition. It is hardly surprising that overuse injuries arise when athletes try to increase their training load while these muscle groups are functioning poorly.

Lower limb overuse injuries often result from the failure of stability muscles to hold the lower limb segments in good posture during the stance phase of running. If gluteus medius, vastus medialis and tibialis posterior are not functioning optimally, there will be an increase in internal rotation of the femur and valgus positioning of the tibiofemoral joint from heel contact to mid-stance phase. The patella will track laterally, leading to an increase in activity of the tensor fascia latae and vastus lateralis and the foot will excessively pronate.

Such faulty mechanics can be the precursor for Achilles tendinopathy, medial tibial stress syndrome (MTSS) or ITB friction syndrome. Furthermore, it seems that after an acute lower limb injury, gluteus maximus activation decreases. This affects performance (reduced propulsive force and lumbopelvic stability), leads to overactivity of the hamstrings and lumbar spine extensors, and is associated with reduced range of movement in hip extension. These changes can manifest as a variety of pain states including extension-related low back pain from excessive shear forces between vertebrae or referred pain in the lower limb as a result of adverse neural tension.

Ben: a bad knee and bad advice

I first saw Ben eight weeks after a Grade 2 medial collateral ligament strain on his right knee. He had been given very poor advice from the hospital where his knee was X-rayed (no fracture). He was told to rest for four to six weeks, after which he could return to his usual activities, which included road running and heavy physical training with the army reserves.

Ben had become concerned with his progress and sought his own treatment, so from four to eight weeks his physiotherapy had consisted of deep transverse frictioning of the ligament, range of movement exercises, proprioception exercises and a programme aimed at gradually increasing the functional load on the ligament. When I inherited Ben as a patient he was just starting to return to running. However, after a week of increasing his distances, he had begun to develop medial knee pain of a chronic nature.

On palpation Ben had become very tender over the medial joint line and in particular the pes anserinus (the common tendinous insertion of semitendinosus, gracilis and sartorius, superficial to the tibial insertion of the MCL). Video assessment of Ben’s running on a treadmill revealed poor medial knee control. At right midstance phase, Ben was laterally tilting his pelvis, prompting an increase in femoral internal rotation, valgus positioning of the tibiofemoral joint and pronation.

It appeared as though the stability muscles crucial for lower limb posture during running were functioning well below their pre-injury ability. This was leading to an increase in rotation (the femur internally and tibia externally rotating) and traction (medially), which was overloading the structures demonstrating tenderness on palpation.

When I tested the functional stability of Ben’s right side in stance, the video assessment observations were confirmed. An effective (although subjective) way to do this is to observe the athlete’s ability to do a single-leg squat. Ben’s squat control on the right was significantly worse than the left, with his lower limb and pelvis beginning, at about 50 degrees of knee flexion, to fall into the same posture demonstrated on running. Ben also showed a key sign of poor strength through glut max and med, by his inability to maintain a neutral lumbar spine position and flex at the hip on the eccentric phase of the single-leg squat.

Ben’s rehab, in my opinion, had overlooked just one aspect, but a crucial one, it turned out. Not enough was done to maintain strength through glut med, glut max and vastas medialis (VMO). In the first week Ben could only perform activation and strengthening exercises that were nonweight bearing or static. However, as the ligament began to scar, he needed to have been working on more functional exercises that target these muscles.

For Ben to run pain-free in his London Nike 10km race in four weeks’ time, we started him on a series of exercises aimed at progressively restoring strength and function through these key muscles. Two maximal repetition sets of single-leg squats were prescribed. For the first set, Ben had to squat down to the lowest he could manage without losing control, to challenge the muscle groups to work through a large range. He improved at this very quickly. Once he had attained reasonable control, we introduced the second set, in which he had to squat only to approximately halfway but with dumbbells in either hand, to help build strength and endurance in the functional range for running.

We asked Ben to use a mirror to ensure that he maintained correct foot, knee and pelvis position throughout. Educating clients on correct posture can take time: it is common for it to take a couple of sessions before an athlete understands particular postural points.

If a client is struggling to control the medial drift of the knee on the eccentric phase, you can place a seat belt or high-resistance exercise band round the thighs, just above the knees. The belt is tightened so that when the knee is in a neutral position, it is taut. The athlete is then instructed to press outwards against the belt to maintain tension and stop it from falling down. This helps to recruit glut med. Ben was also required to feel like he was tensing through his VMO and squeezing his gluts.

We also included in the programme three maximal sets of lunges (ie, performed at full depth and to failure or loss of positional control), with the same emphasis on control and alignment; and isolated glut med strengthening in side-lying (the athlete lies on their side with the underneath leg bent to 45 degrees and the upper leg straight and in slight hip extension. The upper leg is raised and lowered for one repetition. To cheat, the athlete will try and use the tensor fascia lata (TFL) to perform the exercise by letting the pelvis roll back towards supine or by flexing the hip. The athlete should feel fatigue through glut med if the exercise is done correctly).

Once Ben had mastered these exercises, there were just two more things to do before we could return him to the cold, rainy winter streets of London (lucky him). Ben was already learning to pay close and continual attention to his lower limb posture, particularly when he was tiring. Now we added some tougher dynamic challenges to the target muscle groups:

  • fast hopping, punctuated by stopping and holding a balanced position with the knee and hip slightly flexed;
  • 90-degree turns in the air between hops;
  • catching and throwing a ball while hopping;
  • progressively increasing the instability of the surface.

Finally we took all this hard work and put it into Ben’s running. He ran slowly on the treadmill, taking great care that during his right stance phase he resisted the medial movement and rotation of his knee, just as he had been doing with all the exercises. As he became more comfortable with this change in technique, he gradually increased his speed and distance.

With all Ben’s cross training on an elliptical trainer, bike and in the pool, the Nike run proved to be a breeze and best of all, by 12 weeks after his injury, Ben could run pain-free and carry 20kg packs up mountains in camouflage.

knee rehabilitation