Biceps femoris snapping and friction on the fibular head secondary to abnormal distal tendon insertion: 15 cases and a literature review

Abstract

Introduction: Abnormal biceps femoris distal tendon insertion can cause tendon snapping, as is well-known in the literature. The presenting symptom is lateral knee pain, often during sports activities and cycling in particular. The present study tested two hypotheses: abnormal biceps femoris insertion on the fibular head may cause painful friction without clinical snapping, whether visible, audible or palpable; surgical correction achieves good results for pain and return to sport, regarding both snapping and friction.

Material and methods: Between 2006 and 2017, 11 patients were managed for pain secondary to abnormal biceps femoris insertion. In 4 cases, pain was bilateral, resulting in a total of 15 knees: 9 with snapping (in 6 patients), and 6 with friction syndrome without snapping (in 5 patients). All 6 patients with snapping were male, with a mean age of 29 years. Friction without snapping concerned 3 female and 2 male patients, with a mean age of 30 years. Study data included type and level of sport, clinical signs, imaging, type and results of treatment, and type of abnormality.

Results: The insertion abnormality consisted in excessively anterior insertion in the fibular arm in 6 cases, in predominantly tibial insertion in 2 cases, and in isolated tibial insertion in 4 cases. Surgery mainly consisted inrelease and reinsertion of the distal biceps femoris tendon (in 7 cases). All patients were able to return to sport. The mechanism underlying snapping and friction was the same: distal biceps tendon friction on the fibular head secondary to unduly anterior fibular or predominantly or exclusively tibial insertion.

Discussion: The literature reports 24 cases, all of snapping, with between 1 and 3 cases per author. These findings were compared with the present results. With or without snap, symptoms are secondary to abnormal tendon insertion and to activity or sport requiring repeated knee flexion greater than 90°.

Conclusions: (1) Case studies show that lateral knee pain by friction on the fibular head is not systematically accompanied by snapping. (2) In all reports and in the present series, surgery was highly effective on snapping and pain, and patients returned to sport at their previous level.

Level of evidence: IV.

Keywords: Biceps femoris tendon friction syndrome; Lateral knee pain; Snapping biceps femoris tendon; Snapping knee.