Minimal morbidity found after flexor hallucis longus tendon transfer

Postop AOFAS and SF-36 scores were excellent; patients’ daily activities were not limited.

One of the few studies evaluating postop morbidity of flexor hallucis longus tendon transfers yielded excellent American Orthopaedic Foot and Ankle Society and SF-36 scores.

Jeffrey Willers, MD, currently in practice at Southern Sports Medicine and Orthopaedic Center in Nashville, Tenn., presented results at the American Orthopaedic Foot and Ankle Society (AOFAS) 21st Annual Summer Meeting. Willers’ research was performed while he was a fellow at the O.L. Miller Foot and Ankle Center in Charlotte, N.C.

“Despite the frequency that these transfers are performed in the foot and ankle and orthopedic community, little is known about the donor morbidity associated with it,” he said, noting that he and colleagues found only one other study by Coull et al with objective functional data on the subject.

“This study had 16 patients and looked at the AOFAS scores, SF-36 and pedobarograph, and found no significant increase in loading or transfer metatarsalgia. All patients did very well in their AOFAS and SF-36,” he added.

The study, published in the December 2003 issue of Foot and Ankle International, reported that no patients noted a functional weakness, but no objective strength measurements were recorded.

Patient demographics

Willers and colleagues conducted a retrospective review of 54 flexor hallucis longus (FHL) transfers in 52 patients at the Miller Orthopaedic Clinic from 1998 to 2004. Preoperatively, all patients had insertional tendinosis or chronic Achilles tendon rupture.

Surgeons performed FHL transfer through a single longitudinal incision along the medial border of the Achilles tendon. After debriding the Achilles tendon, they used a biotenodesis screw to secure the FHL transfer within the bone tunnel, and used a corkscrew suture anchor for Achilles reattachment.

The researchers excluded nine patients: six who had undergone bilateral procedure, one with amputation on the contralateral side, one with arthrodesis on the contralateral side and one with profound peripheral neuropathy. Other patients were either lost or unavailable for follow-up, leaving 24 patients with a mean age of 56 years (range 39 to 76 years). There were 12 men and 12 women. Twelve patients experienced the pathology in their right foot and 12 in their left.

Excellent functional outcomes

At a mean follow-up of 29 months, researchers clinically evaluated the patients’ hallux function using the AOFAS hallux metatarsophalangeal-interphalangeal scale and the SF-36 score. In addition, they objectively evaluated patients with computerized pedobarography to determine dynamic weight-bearing pressure/time mapping and detect changes in forefoot loading, compared to the contralateral unaffected foot. They also used the dynomometer to test the strength of the hallux.

Researchers found that patients had excellent functional outcome scores for the AOFAS hallux MTP-IP and SF-36 scores. The mean AOFAS hallux MTP-IP score was 96 (range, 72 to 100) and the mean SF-36 score was 71 (range, 23 to 93). “Unfortunately, there was no preoperative comparison for SF-36 or AOFAS hallux MTP-IP,” Willers said.

Compared to the contralateral unaffected foot, pedobarographic measurements indicated a decrease in pressure below the distal phalanx of the hallux, but it was not statistically significant. The measurements also showed no difference in plantar pressure at the first or second metatarsophalangeal joints. Using the dynomometer, researchers found a statistically significant difference (P=.037) in the hallux flexion strength.

For more information:
Richardson D, Jones C, Cohen B, et al. Evaluation of the morbidity of flexor hallucis longus tendon transfer. Presented at the American Orthopaedic Foot and Ankle Society 21st Annual Summer Meeting. July 14-17, 2005. Boston.
Coull R, Flavin R, Stephens MM. Flexor hallucis longus tendon transfer: evaluation of postoperative morbidity. Foot and Ankle International. 2003; 24(12):931-4.