Split tendon transfers for the correction of spastic varus foot deformity: a case series study

Abstract

BackgroundOveractivity of anterior and/or posterior tibial tendon may be a causative factor of spastic varus foot deformity. The prevalence of their dysfunction has been reported with not well defined results. Although gait analysis and dynamic electromyography provide useful information for the assessment of the patients, they are not available in every hospital. The purpose of the current study is to identify the causative muscle producing the deformity and apply the most suitable technique for its correction.MethodsWe retrospectively evaluated 48 consecutive ambulant patients (52 feet) with spastic paralysis due to cerebral palsy. The average age at the time of the operation was 12,4 yrs (9-18) and the mean follow-up 7,8 yrs (4-14). Eigtheen feet presented equinus hind foot deformity due to gastrocnemius and soleus shortening. According to the deformity, the feet were divided in two groups (Group I with forefoot and midfoot inversion and Group II with hindfoot varus). The deformities were flexible in all cases in both groups. Split anterior tibial tendon transfer (SPLATT) was performed in Group I (11 feet), while split posterior tibial tendon transfer (SPOTT) was performed in Group II (38 feet). In 3 feet both procedures were performed. Achilles tendon sliding lengthening (Hoke procedure) was done in 18 feet either preoperatively or concomitantly with the index procedure.ResultsThe results in Group I, were rated according to Hoffer's clinical criteria as excellent in 8 feet and satisfactory in 3, while in Group II according to Kling's clinical criteria were rated as excellent in 20 feet, good in 14 and poor in 4. The feet with poor results presented residual varus deformity due to intraoperative technical errors.ConclusionOveractivity of the anterior tibial tendon produces inversion most prominent in the forefoot and midfoot and similarly overactivity of the posterior tibial tendon produces hindfoot varus. The deformity can be clinically unidentifiable in some cases when Achilles shortening co-exists producing foot equinus. By identifying the muscle causing the deformity and performing the appropriate technique, very satisfying results were achieved in the majority of our cases. In three feet both muscles contributed to a combined deformity and simultaneous SPLATT and SPOTT were considered necessary. For complex foot deformities where the component of cavus co-exists, supplementary procedures are required along with the index operation to obtain the best result.

The split anterior tibialis tendon transfer procedure for spastic equinovarus foot in children with cerebral palsy: results and factors associated with a failed outcome

“…Arrows showed the two halves of the anterior tibialis tendon with a balanced position of the foot after the procedure the other hand, others have reported that the EMG data did not correlate well with the clinical findings and warned of the use of needle EMG while children walk [2,9]. In this study, the decision to perform the SPLATT procedure was based on the observational pre-operative gait analysis and the positive reflex withdrawal test [1,11]; however, the observers agreed that the deviations of the gait were rated fair to moderate [17], which could affect the surgical planning [9,11,18]. Furthermore, AT tendon overactivity could be a contributing factor of a failed outcome if a split PT transfer was employed [9].…”

“…This difference may be due to the fact that children with GMFCS level 3 or more has a poorer ambulatory capacity to begin with so any visual assessment of their gait is variable [17] and will increase the chance of having an unpleasant outcome. Results of children with GMFCS levels 3 and 4 and levels 1 and 2 were similar; this would imply that the CCP did not have a sufficient follow-up time [11,16], thus the number of children may be too small to detect the difference between the groups. Concomitant knee and hip surgery and type of cerebral palsy can increase the deterioration of the gait during the follow-up period but the authors did not detect any significant association between these factors and a failed outcome [14].…”

“…A surgical treatment is advised when the deformity cannot be controlled by conservative means [4,8,13]. In this report, the SPLATT procedure combined with tendon and bone operations at the posterior aspect of the ankle was performed as a part of the MLSL surgery to correct the equinovarus foot deformity and improve foot posture suitable for gaiting [1,10,11,15,16]. The majority of the children maintained their GMFCS levels and balanced-plantigrade foot position in the operated foot at their latest visit.…”

“…Other factors such as the level of cognitive involvement, the degree of the muscle spasticity and family compliance may also influence the decision for the operation [11]. These factors could affect the ambulatory status of CCP in the long term.…”

“…The tendo achilles (TA) and ankle plantar flexor muscles such as the PT, flexor digitorum longus (FDL) and flexor hallucis longus (FHL) were lengthened to correct the equinus deformity [1,11]. The subtalar fusion was performed if needed.…”