Case of the Week: Bicyclist Knee Pain

Patient: 30 year old IT consultant

Presentation: Patient has signed up to participate in a week-long bicycle trek from Los Angeles to San Francisco in the first week of June. In his training for this ride, he has been taking longer and longer rides on the weekends and short rides during the week. This past weekend, he tried to take a 74 mile ride, but had to stop at 30 miles due to right knee pain. This pain has been nagging for the last few weeks, but only presents while cycling and usually goes away once the ride is over. This past week, the pain was significant enough that he stopped riding, and walked back to an area where he could call a friend to pick him up and bring him home. There is no radiation of pain, numbness, tingling or significant weakness. He has never had an injury to the right side and has not other complaints.

Examination: The right vastus medialis oblique (VMO) is tight and tender +2/4 with mild edema (swelling) at the insertion on the patella. Right knee range of motion is within normal limits. Muscle testing reveals a weak right VMO. Deep tendon reflexes are within normal, as is sensation in the lower extremities. Orthopedic tests for meniscus involvement, chondromalacia patella, cruciate ligament tears and medial or lateral instability were all negative.

Discussion: As we have previously discussed, the muscle balance in the knee is crucial. When performing a repetitive motion, such as cycling, the knee is repeatedly put under stress in both flexion and extension. If the muscles of the knee are not putting synchronized forces on it, irritation can result. In this case, the patient already had a weakness in his right VMO. He just never noticed it until he was training for this ride. The VMO is a common muscle to have a weakness in. It doesn’t mean he trained incorrectly or was somehow deficient. Many athletes, including runners, cyclists and skiers end up irritating their VMO’s with increased activity. The key is early detection and appropriate strengthening.

In this case, the patient has already significantly irritated the VMO. It is fortunate that he has decided to seek help at this time because continuing to train on an injured knee could lead to even more significant injuries later on. As the knee flexes and extends, the VMO and the Vastus Lateralis Oblique(VLO) must pull on the knee cap (patella) equally to ensure that it tracks in a straight line up and down. When the VMO is weak, the patella does not track properly, leading to pain, inflammation and eventual damage to the joint.

Treatment: First, we need to prevent further irritation and control pain. We do this by icing the affected area, gentle massage to promote lymphatic drainage, and myofascial release to reduce tension in the VMO. Once the VMO is loose and no longer irritated, the patient must begin a specific strengthening regime to build up the VMO. It is important to strengthen evenly on both legs to ensure proper muscle balance.

Outcome: The patient is improving steadily. He has been able to go on several short rides without pain, and is looking forward to increasing his distance now that his knee is balanced.

Suggestion of the Week:
Get good equipment
If you are a cyclist, buy the best bike you can afford. Then have it fitted to you by an expert. (This is a link to the best bike fit guy I know). A good bike fit should NOT take only 10 minutes. There are a lot of little aspects of fitting a bike to its rider that must be taken into account. Without a good bike fit, you are more prone to injury and you will be less efficient in your riding, making you slower and more fatigued. Same goes if you are a runner. Get your feet evaluated and buy shoes for your feet and your needs. Then, take care of them! Keep a log of how many miles your shoes have on them. Once a shoe has hit between 300 and 500 miles (depending on the brand) you need to make them your new gardening shoes. A running shoe has a lifespan and trying to push a shoe past its life will only result in decreased performance and possible injury.

Exercise of the Week:
VMO Strengthening
This is so easy, it’s ridiculous. Sit in a chair. Turn your foot out as much as you can. Straighten your leg. Return your foot to the floor. Repeat until you feel fatigue in the lower middle section of your thigh muscle. If you need more of a challenge, add a small weight to your ankle or use tubing tied to your foot and the chair leg. By turning your foot out, you isolate the VMO. Don’t be surprised if you have less endurance and strength in this position than you do with your leg straight. When the leg is straight, you are using all of your quadriceps. By isolating the VMO, you can strengthen focally and improve the muscle balance across your knee. (Image provided by Dr. Henry Domke, The Living Healthly Podcast)