Biceps Femoris Tendonitis
The hamstring muscles at the back of the thigh are very large and powerful. When they contract they bend the knee backwards. The hamstrings are broadly split into two halves – one half attaches to the medial (inner) side of the top of the shin. The other half goes to the lateral (outer) side – this is called the Biceps Femoris muscle. The bottom part of the muscle turns into a tendon, and this tendon attaches to the top of the head of the fibula (the small bone on the outer side of the shin).
As with any tendon, the Biceps Femoris tendon can be damaged from trauma (e.g. twisting injuries), from a sudden pull or from overuse. The tendon can very occasionally completely tear or avulse off the fibular head – which is normally a fairly severe injury that often requires surgery. More often, though, the tendon may sustain a partial tear (sprain) or the tendon may become inflamed (tendonitis) or, in the longer term the tendon may become degenerate (tendinosis), with a decreased blood supply and patches of scar tissue in it.
The word ‘tendinopathy’ simply means ‘something wrong with a tendon’, but it doesn’t describe what the exact pathology is, i.e. whether it is a sprain, inflammation or degeneration.
Biceps tendinopathy causes pain around the outer (lateral) side of the knee, specifically in the area where the tendon sits, just above the fibular head. This pain tends to come on with any kind of exercise that involves strong or repeated contraction of the hamstrings, such as running.
The best form of imaging to check the whole knee and to double check for any potential intra-articular damage deep inside the knee is an MRI scan.
However, the most sensitive and accurate investigation for specifically looking at superficial tendons and for differentiating between tendonitis, tendinosis or sprains is an Ultrasound Scan with Doppler.
Most cases of Biceps Femoris Tendinopathy respond well to the classic trial of rest, ice and anti-inflammatories. Once the diagnosis has been confirmed by appropriate imaging, then most people benefit from a course of physiotherapy treatments.
Only if symptoms persist and are bad enough despite appropriate physio treatments should one then consider more invasive potential treatments. If needed, tendinopathies can be treated with various types of injection (steroid injections, dry needling, PRP injections) or by Extracorporeal Shockwave Therapy (ESWT). This is the remit of Sport & Exercise Medicine Specialists (Sports Physicians/Doctors) who specialise in the non-surgical management of tendinopathies. Rarely, if ever, does Biceps Femoris Tendinopathy ever actually need any kind of surgical treatment.