This month DR MIKE MULDER sheds some more light on dreaded knee injuries
When you ride out onto a trail less travelled, it is always nice to have a companion. Going below the waist to discuss knee problems is certainly outside my comfort zone, so I have enlisted the help of my partner, Dr Roy Endenburg. Roy certainly knows his way around the knee and he is a member of the distinguished Amabubesi Club, which attests to his cycling pedigree.
Although the knee is a hinged joint, it is an inherently unstable structure. It has a complex articulation surface, which manages massive loads and forces. The joint surfaces are comprised of the lower end of the femur (thigh bone), which has 2 “knuckles” called condyles, and the flat upper end of the tibia (shin bone). The meniscii (singular: meniscus) are the semi-circular cartilage wedges that keep the condyles centred on the tibial surface. The knee relies on a complex group of ligaments to achieve motion: the cruciate ligaments (anterior and posterior) lie internally, while the collaterals (medial and lateral) lie on the sides. Power to bend and straighten the knee is generated by the hamstrings and quadriceps muscles respectively. This power is transmitted to the tibia via the patella (knee cap), which improves the angle that the quadriceps tendon acts on the bone. As the knee moves, the patella glides on the front surface of the femur. The bulk of knee problems that Roy sees fall into 2 categories: (1) sudden injuries from falls and crashes, and (2) gradual onset of pain, related to technique and bike set-up.
Injuries from accidents involve the bone, the soft tissues (cartilage, meniscus or ligaments)
or a combination of both. Fractures of the patella or upper surface of the tibia (tibial plateau) are generally as a result of direct impact of your knee against the ground, rock, tree, pole, sign, car or whatever stopped your ride! There is often little doubt that a fracture has occurred … think serious pain and dramatic swelling. X-rays and CT scans will clarify the extent of the injury and determine treatment options. Not infrequently these fractures are discovered late when pain does not settle. Roy’s advice is if you struggle to bear weight through the knee after a fall, particularly when climbing stairs, then the cause must be found. Soft tissue injuries are the “wash and lube” of knee surgeons. The ligament or meniscus is frequently injured during a twisting manoeuvre at the knee. For example, when your foot is trapped in the cleat during a fall. These injuries are associated with pain and swelling of the knee, difficulty bending and sometimes an unstable feeling. Soft tissue injuries do not show up on x-rays or CT scans. Diagnosis requires a combination of skilled examination and an MRI scan, which shows soft tissue structures better. If you find yourself literally on your knees after a bike accident, seek advice from a specialist with an interest in knees. The skill is to know which injuries need surgery, and which can be treated with rest and rehab.
DREADED KNEE PAIN
Knee pain in sport is common. It is often the reason many runners see the light and take up
cycling. Knee pain is frequently linked to an old sports injury or due to “wear-and-tear” related degeneration of the joint cartilage. Let’s look at some of the causes of knee pain specific to cycling. Top of the list is simply overuse. Cyclists are frequently guilty of overdoing their training miles, or rapidly escalating their training in preparation for an event. Unless the training is gradually built up over time, the cartilage, ligaments and tendons are subjected to excessive loads. The key is to be sensible, plan your training and plan for gradual increases, including rest and recovery periods. Anterior knee pain located in the front of the knee may be due to excess compression between the patella and the lower femur. Once again, over- use is commonly a cause, but so too is pedalling technique. High gear low cadence climbing places unnecessary load through this area. Unfit or inexperienced riders often prefer this style of riding. This problem can be rectified with adopting a lower gear and spinning a higher cadence. Altering technique to incorporate the hamstrings in the upstroke portion of the pedal action also reduces the load through the patella. One of the first steps in the correction of anterior knee pain is correct set-up of your bike. All too often saddle height, tilt and fore/aft position is the difference between efficient versus painful load-bearing through the knee. Seemingly subtle changes can be highly effective. Pain experienced on either side of the knee (inner: medial and outer: lateral) may be due to the load not being equally distributed through the condyle. Rotation of the foot relative to the knee differs between individuals. It is somewhere on the spectrum between “duckfoot” and “pigeon-toed”. You should take cognisance of this with respect to the position of your foot on the pedal. This angle is dictated by the position of the cleat on your shoe. Badly placed cleats alter the line of force through either facet of the joint, creating an unequal load and leading to pain. Make sure that when you replace shoes or cleats that you replicate your set up perfectly. Just a cautionary note on self-medicating with anti-inflammatories while riding. Many “intelligent and educated” cyclists have ended up in ICU with kidney failure. Be prudent. I know it’s hard to rest, but make an educated choice. Find out what is wrong and make educated decisions. An article on such a vast topic as knee pain and problems can run into pages which will not please the editor. Hopefully this broad guide gives you a starting point to think about assessing and avoiding the dreaded knee pain.
PAIN POSSIBLE SOLUTION
Front of knee Raise saddle 1cm
Back of knee Move cleat forward a few mm
Outer side of the knee Rotate your cleat inwards
Inner side of the knee Rotate your cleat outwards
Pain behind the kneecap A few very light training sessions. Better to rest