Long-Term Effects on Adult Foot Function After Tibialis Anterior Tendon Transfer for Relapse of Idiopathic Clubfoot Deformity Treated with the Ponseti Method.

Talipes equinovarus (clubfoot) is an abnormality that is congenital (present at birth) in which the foot is twisted out of shape or positioning. The Ponseti method of treatment includes serial manipulations and application of casts and braces. Relapse of the deformity has been reported in a prevalence of 7-56 per cent. Relapses are often found to be the result of inadequate, short-term use of bracing and nonadherence to bracing recommendations. Further bracing can be utilized, however, proves challenging as the child ages and is less tolerant of bracing. The use of a tibialis anterior tendon transfer to the outside of the foot can be utilized to maintain the improved positioning that was accomplished with repeated casting. A retrospective review of prospectively collected data was performed to evaluate long-term outcomes on foot function in adults who had been treated for relapsed idiopathic clubfoot in childhood. This review collected data on all patients treated for idiopathic clubfoot using the Ponseti method at the University of Iowa from 1950 through 1967. All aspects of treatment were performed by Dr. Ignacio Ponseti. Follow-up data was obtained on thirty-five of the original 126 patients whom medical records were reviewed. Of this thirty-five, forty percent had underwent the tibialis anterior tendon transfer and served as the study group while the remaining sixty percent who did not undergo the tendon transfer served as the reference group. The average duration of the time between tibialis anterior tendon transfer and follow-up was forty-three years.

In follow-up, patient’s completed three outcome questionnaires: the American Academy of Orthopaedic Surgeons (AAOS) Foot and Ankle Outcomes Questionnaire, the Laaveg-Ponseti questionnaire, and the Foot Function Index (FFI). They also underwent a thorough physical examination, standing radiographs, a pedobarograhic analysis with pressure sensor as they walked freely across the room and surface electromyographic (SEMG) patterns were obtained from the tibialis anterior, lateral gastrocnemius and peroneus longus muscles. Results demonstrated that no patients in the tendon transfer group had a relapse or had required additional treatments for clubfoot at time of final follow-up. There was no statistically significant difference in the number of casts required in the initial treatment between the transfer and reference group. Questionnaire results showed no significant differences between the tendon transfer group and the reference groups on the AAOS Foot and Ankle Outcome or FFI. The Laaveg-Ponseti functional ratings were similar in both groups. Physical findings demonstrated that there was no significant difference in passive ankle plantar flexion-dorsiflexion and forefoot inversion. Nor was there significant difference in passive ankle dorsiflexion at any level of applied torque. Motor strength of the tibialis anterior and peroneal muscles was comparable between the tendon transfer and reference groups. Radiologic findings demonstrated that those whom underwent tendon transfer did have significantly smaller anteroposterior talocalcaneal angle than the reference group. They also demonstrated more talar flattening than the reference group of statistical significance. With the exception of more moderate to severe osteophyte (bone spur) formation in the navicular-cuneiform joint in the tendon transfer group overall degenerative changes and bone spur formation were similar between groups. Pedobaraographic analysis did not show any difference of significance between groups. Additionally there was no difference between the two groups in regards to SEMG data for firing times, nor when the tendon transfer group was compared to healthy college age students.

The authors of this study conclude that the results establish the effectiveness for the tibialis anterior tendon transfer in that there was no subsequent relapse of requirement of additional casting or surgical intervention for clubfoot. They noted that while there was greater bone spur formation at the navicular-cuneiform joint and talar flattening was more present upon radiographic evaluation in the tendon transfer group this did not have association with increased pain, greater medication use or difficulty walking. Several limitations were present in this study particularly the low patient follow-up rate of 28 per cent.