The popliteal entrapment syndrome.

Five examples of the popliteal entrapment syndrome have been reported in 4 patients aged between 17 and 41. The diagnosis in each case was made pre-operatively. The anatomical anomalies consisted in three instances of an abnormally high insertion of the inner gemellus (medial head of gastrocnemius) muscle tendon with the artery located twice in front and once in the middle of the tendon, in another instance compression was due to a hypertrophic musculus plantaris and finally, in the last instance, the anomalies were caused by abnormal fibrous bands. In two instances the artery was thrombosed, in three it was compressed in an intermittent fashion. The patients responded well to treatment, by a graft in the case of thrombosis, and by sectioning the abnormal insertions of the gemellus muscle or the fibrous bands in the others. The frequency of these different anatomical types, the relative evolutivity and the embryological hypotheses are studied in the 111 cases recorded in the literature between 1970 and 1983.