Comparison of two different methods in preoperative planning of the amount of lengthening in Z achilloplasty technique.

Achilles tendon lengthening (ATL) surgery is a technique that is frequently used in the surgical treatment of contracture of the Achilles tendon seen in many pediatric orthopedic problems such as cerebral palsy, clubfoot, pes planovalgus and myelomeningocele. It is important to appropriately adjust the amount of ATL. However, the literature on the preoperative calculation of the required amount of tendon lengthening is limited. The aim of the study was to compare the reliability of the two different methods of predicting the amount of ATL. Eighteen feet of 16 patients who underwent ATL with Z-plasty technique were included in the study. The required amount of ATL was calculated as double blind according to the Cosine theorem and a method that was described by Garbarino et al. in 1985 and compared with the amounts of ATL applied during the operation. The mean amount of lengthening was 25.24 mm during surgery. The required amount of lengthening was 41.55 ± 11.0 mm, according to the Garbarino's method. The required amount of lengthening was 23.93 ± 9.03 mm, according to the Cosine theorem. The quantities calculated according to the Cosine theorem showed excellent agreement with the amount of lengthening during surgery. The quantities calculated according to the Garbarino's method showed poor agreement with the amount of lengthening during surgery. The calculation of the amount of ATL required in the treatment of the equinus deformity before surgery is possible by Cosine Theorem. The method of Cosine theorem is more reliable than the previous method described by Garbarino et al.