Jumper's knee or infrapatellar tendonitis is a chronic inflammatory disease affecting the tendon between the kneecap and the tibia resulting in pain, stiffness and weakness. The normal collagen fibres in the tendon can become disorganized and sometimes replaced by a tight cyst with gel-like substance. Physiotherapy (clic to..) is definitely the initial step to try to resume sports activities once diagnosis is confirmed with ultrasound or MRI. If this fails (in a minority) , surgery can be indicated to decompress the tendon. Rehab in these circumstances is challenging and time-consuming (up to a year).

Cruciate ligaments are not just simple elasticated collagen bands but sophisticated fine tuned structures surrounded by a neuro-vascular plexus providing continuous bio-feedback during knee joint motion. In moments of acute stress the stretched ligament sends out info to immediately recruit all possible muscle strength. Sometimes the impact on the knee is too great or reaction speed too slow, hence tear partially or completely. Depending on the overall status of the knee, it may make sense to reconstruct the ligament usually with one of the hamstrings. Unfortunately, although ACL-reconstruction usually allows re-participation in football, rugby,..it does not necessarily protect against progressive wear and tear of the cartilage. Alternatives consist of an intensive rehab programme with physiotherapists (to be started anyway) or usage of braces (http://www.ossur.com) . Lots of people with ACL tears are perfectly capable of engaging in activities of daily living without pain or instability. ACL or PCL reconstruction is best done by expert surgeons doing more than 30 similar procedures every year.

The classic 'wear and tear' is still subject to lots of investigations and research. Why is it that in some 80 year old heavy labourers cartilage is still pristine and in other 30 year marathon runners bare bone is covering the joint surfaces? Genetics? Loading cycles? Different healing potential? We know already that inflammation takes place and that cartilage as a firm water mattress is losing water and becomes brittle. Cartilage cells unfortunately can not move out to help others - they are stuck. Yes, they can rejuvenate by dividing themselves but only 30 times in a life time. Basically, on any given joint surface each cell has about thirty credit units. Use them, lose them and then? Then clefts appear, bigger and bigger and as with icebergs chips come off, if not the odd big chunk. Symptoms of pain and stiffness induced by minimal cartilage damage can be relieved by weight reduction, muscle strengthening, intra-articular cartilage injections (www.synvisc.com) or dietary modifications (not proven yet). More severe damage could require arthroscopic debridement or reconstruction. Exciting research has indeed shown that cartilage can be transplanted or even regrown in the lab. THE KEY to success ultimately will be the discovery of a bio-glue enabling cultured cartilage to grow in and become stuck to the bone. Watch that space!

Knee joint replacements together with hip prosthetic procedures are one of the great achievements in musculo-skeletal care over the past 40 years. Badly worn out knees can be extremely painful and in the past forced people to become wheelchair bound. The idea that resurfacing the bare bone surfaces with metal alloy and bio-binding would reduce the painful friction and allow pain free motion is indeed revolutionary. Bio-engineers together with knee surgeons are continuously attempting to create a design and materials that could imitate the ultimate - the normal biological knee. We are certainly not there yet but lifespan of a successful prosthesis can be 10-20 years. Obviously, it is paramount to understand that the initial goal of knee joint care is preservation of your own as long as possible. Indeed, despite the success rate of 95% there are some major possible (albeit) rare complications such as infection, deep venous thrombosis.