TENDON TRANSFER COMBINED WITH CALCANEAL OSTEOTOMY FOR TREATMENT OF POSTERIOR TIBIAL TENDON INSUFFICIENCY - A RADIOLOGICAL INVESTIGATION

We present the radiographic results after flexor digitorum longus tend on transfer combined with a medial displacement calcaneal osteotomy fo r the treatment of posterior tibial tendon insufficiency. Eighteen pat ients with posterior tibial tendon insufficiency were reviewed from 12 to 26 months after surgery. The 15 women and 3 men had a mean age of 54 years (range, 38-72 years). The talar-first metatarsal and talonavi cular coverage angles were measured before and after surgery on the an teroposterior weightbearing radiographs. The mean preoperative talar-f irst metatarsal and talonavicular coverage angles were 21 degrees (ran ge, 3-45 degrees) and 34 degrees (range, 0-55 degrees), respectively. The mean postoperative values for these angles were 8.5 degrees (range , 0-35 degrees) and 21 degrees (range, -30-45 degrees), respectively. The mean talar-first metatarsal angle decreased from 21 degrees to 8.5 degrees, a mean improvement of 12.5 degrees, and the mean talonavicul ar coverage angle decreased from 34 degrees to 21 degrees, a mean impr ovement of 13 degrees. On the lateral weightbearing radiographs, the t alar-first metatarsal angle and the distance from the medial cuneiform to the floor were measured before and after surgery. The mean preoper ative values were -22 degrees (range, -10 to -40 degrees) and 9 mm (ra nge, 1-19 mm), respectively. The mean postoperative values were -9 deg rees (range, +5 to -25 degrees) and 16 mm (range, 10-28 mm), respectiv ely. The mean talar-first metatarsal angle decreased from -22 to -9 de grees (a mean improvement of 13 degrees), and the distance from the me dial cuneiform to the floor increased from 9 to 16 mm (a mean improvem ent of 7 mm). We conclude that the use of a combined medial displaceme nt osteotomy of the calcaneus with a tendon transfer for treatment of posterior tibial tendon insufficiency may offset the inherent weakness of the flexor digitorum ion-gus transfer by reducing the antagonistic deforming force of heel valgus.