Medial Hamstring Tendonitis
Medial Hamstring Tendonitis / Pes Anserinus Bursitis / Semimembranosus Bursitis
Blimey! … that lot’s a bit of a mouthful, isn’t it?! So, to try and explain it all ---
The hamstrings are the muscles at the back of the thigh, which bend the knee when they contract. The hamstrings arise from the ‘sitting bone’ at the base of the pelvis called the ischial tuberosity. They pass down the back of the thigh in two main groups: on the outer (lateral) side is the biceps femoris muscle, and this attaches onto the top of the fibular head (at the outer side of the top of the shin). On the inner (medial) side, there is a group of muscles from both the hamstrings and the adductors, which converge and whose tendons attach to the inner (medial) side of the top of the front of the shin. These muscles are the:-
The tendons converge into an area on the inner side of the front of the top of the tibia (shin bone) called the pes anserinus (meaning ‘bird’s foot’).
In addition to all this, there are various sacs of fluid around these tendons that act as lubricants, preventing the tendons from rubbing. These sacs are called ‘bursae’ (singular = bursa).
Any of the tendons or their tendon sheaths, or any of the bursae around this area can become inflamed, either in relation to trauma, or from overuse or in response to surgery and/or rehab on the knee.
If the tendons or their tendon sheaths are inflamed then this is called ‘medial hamstring tendonitis’. If the area of attachment of the tendons at the front of the shin is inflamed then this is called ‘pes anserinus bursitis’. If the bursa next to the semimembranous (on the inner side of the knee, just above the actual joint line) is inflamed, then this is called semimembranosus bursitis.
All of these conditions are very similar and cause very similar symptoms, with pain around the medial side of the knee, particularly with any kind of exercise that involves repetitive or heavy hamstring contractions.
None of these conditions are ‘dangerous’, but they can be painful and annoying.
The best investigation to check the inside of the knee, to make sure that there are no problems inside the joint (such as a medial meniscal tear or medial compartmental articular cartilage damage), is an MRI scan.
The best investigation to actually check specifically for tendonitis/bursitis is an Ultrasound Scan.
Once the exact diagnosis has been confirmed, then most patients respond very well to conservative (non-surgical) treatments such as:-
If, despite trying all of the above, the symptoms persist then the next step is to have a ultrasound-guided steroid/cortisone injection. This acts as a very powerful anti-inflammatory and it normally cures the problem, although sometimes it can be necessary to repeat the injection more than once if symptoms persist or subsequently come back after an injection.
Note well, that in my personal opinion there is never a good reason to inject in or around someone’s medial hamstring tendons blindly in clinic …. It is far more accurate and safe for a Consultant Radiologist to do an ultrasound scan and for them to perform the injection under ultrasound guidance, in the X-ray Department, so that they can see the exact spot that is inflamed and so that they can actually watch the tip of the needle going into exactly the correct place before injecting the steroid. (This does, of course, presume that you’ve actually got direct access to an appropriate Consultant Radiologist, which is certainly the case in the private sector but not always in the NHS.)