Functional popliteal entrapment syndrome in the sportsperson

To define the clinical syndrome of functional popliteal entrapment comparing pre and post surgical clinical outcomes with pre and post-operative provocative ultrasonic investigations. Further, to suggest a management pathway to differentiate chronic exertional compartment syndromes and concomitant venous popliteal compression.

In 32 claudicant sportspersons, 55 limbs were characterised pre-surgery clinically, with provocative testing including hopping, and following a series of non-invasive tests. The clinical findings, ankle brachial indices (ABI) and duplex outcomes were compared pre-operatively, at 3 months post-operatively (n = 52) and in the long term i.e. 16 months (n = 17).

At 3 months, all 55 limbs had clinical follow up. 52 of the 55 limbs had follow up with ultrasound with provocative manoeuvres. The ABIs normalised in 46 (88%). There were 40 of 52 (76%) that became asymptomatic post surgery with a normal scan. There were 4 of 52 (8%) who were clinically asymptomatic but with residual obstruction on duplex and who were able to resume their usual lifestyle. There were 4 (8%) that had abnormal findings both on post-operative scan and clinically. Re-operation on 2 limbs corrected the duplex findings and the symptoms. There were 4 (8%) limbs that had normal duplexes but continued with symptoms albeit varied from the presenting symptoms. In the longer term, a further 2 became symptomatic at 2.8 years requiring a further successful intervention. (Concomitant popliteal venous obstruction was present in 5 limbs (10%) on standing.)

In the claudicating sportsperson, where there are no well characterised specific anatomical abnormalities, the syndrome can be characterised by provocative clinical (particularly hopping) and non-invasive tests. A positive clinical outcome with surgery can be predicted by abnormal pre-surgical ultrasonic investigations and confirmed later by a similar normal post surgical study. Concomitant venous compression may occur while standing with both syndromes related to muscle hypertrophy.