Case Reports

Snapping Biceps Femoris Tendon

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A conservative treatment with physical therapy, activity modification, and a Cho-Pat knee strap (to provide a posterior-to-anterior buttress and to prevent snapping) was attempted for 4 weeks. However, the patient could not tolerate the strap, and the activity restraints prevented him from performing his job as an active-duty soldier. Given the failure of conservative treatment, operative intervention was elected.

Upon exploration of the biceps femoris insertion, the accessory anterolateral tibial insertion was readily identified (Figure 3). Notably, the expected normal lateral edge insertion was thickened and extended beyond the lateral edge, distal, and anterior on to the fibular head (Figure 4). The anterolateral tibial band was released first. However, the snapping remained evident. The thickened anterior fibular accessory band was then released back to its normal, lateral edge, and at this point, no further snapping was observed with deep flexion of the knee. Inspection of the remaining posterolateral and lateral edge insertion demonstrated a healthy, 1-cm thick tendinous insertion. The accessory slips were completely excised, and the incision was closed without any additional repair or re-insertion (Figure 5). The patient presented no complications postoperatively. He was allowed to bear weight as tolerated and was limited to stretching and gravity resistance training for 4 weeks. At 1 month, the patient was released to progress back to full activity. By 8 weeks postoperative, he remained free of snapping and resumed his regular running routine and military duties without restriction or pain.

DISCUSSION

Release of the anomalous bands with no further repair or re-insertion of the biceps femoris allowed this active-duty soldier to resume full running and duty-related activities in <2 months. In this particular patient, given his anatomy, the treatment was successful. The literature indicates that optimal results and surgical approach depend upon the pathological anatomy encountered.

Date and colleagues4 described a similar anatomical anomaly as with our patient, whom after the release of tibial insertion, snapping was still observed, thus requiring the release of anterior fibular insertion. They noted the necessity of suturing the accessory limbs onto the periosteum of the fibular head to achieve a stable biceps femoris.

In other cases, abnormal bony anatomy of the fibula has been shown to cause snapping. Vavalle and Capozzi5 described a case of snapping biceps in a marathon runner, who needed partial resection of the fibular head to eliminate snapping. The runner made a full return to the sport. Fung and colleagues2 described a similar approach to a 17-year-old cyclist; however, this patient presented exostoses of the bilateral fibular heads. The exostoses were bilaterally excised, and the snapping ceased. Kristensen and colleagues13 described a patient with an anomalous tibial insertion. Rather than releasing the tibial insertion, a partial resection of the fibular head allowed for cessation of snapping.

Other authors advocate the detachment and anatomic re-insertion of the biceps femoris into the fibular head. Bernhardson and LaPrade6 reported a series of 3 patients requiring this approach with excellent results. Bansal and colleagues8 were the first to describe a soccer player with an isolated injury to the knee as a traumatic cause for a snapping biceps femoris. After failure of conservative treatment attempts, exploration and re-insertion through a bone tunnel allowed for return to the sport. Hernandez and colleagues11 and Lokiec and colleagues12 both described the reproduction of the normal biceps femoris anatomy through re-insertion procedures after identifying patients with abnormal anatomical insertions as causes for snapping.

CONCLUSION

We presented a case of an active military service member with a unilateral snapping biceps femoris tendon due to an anomalous distal insertion on both the proximal tibia and anterior fibular head. The release of abnormal insertions and maintenance of his normal anatomical insertion allowed for a quick and effective return to running and duty at full capacity. Although other surgical approaches have been described to include partial fibular head resection or anatomical re-insertion, we believe that the approach to this rare condition should be anatomy-based as the causes of snapping can significantly vary. We believe that if the normal posterolateral and lateral edge insertions of the biceps femoris are intact, removal of the abnormal anatomy without any repair or reconstruction can safely lead to successful surgical outcomes.

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