Modified split tendon transfer of posterior tibialis muscle in the treatment of spastic equinovarus foot deformity: long-term results and comparison with the standard procedure

Abstract

Introduction Split tendon transfer of tibialis posterior (SPOTT) is a treatment option for the hindfoot varus deformity in patients with cerebral palsy (CP). The purpose of this study was to present the long-term results of the newly modified SPOTT procedure developed by our senior author and compare it with the standard SPOTT technique in equinovarus foot deformity due to CP. Method Our retrospective cohort study included patients with spastic foot deformity due to CP treated with the standard or modified SPOTT technique. Patients' age at the time of the surgery was ≥ five years with follow-up period of at least four years. Surgical outcomes were evaluated using Kling's criteria during the patient's last follow-up visit. Results The analysis included 124 patients (146 feet), where 105 feet were treated by the standard SPOTT technique and 41 feet by the modified SPOTT technique. Patients' median age at the time of the surgery was 11 years. Patients were followed-up for a median period of eight years during which the modified SPOTT technique showed significantly better surgical outcomes compared with the standard group (excellent/good results in 38 feet, 92.7%, vs. 79 feet, 75.2%, p = 0.02). Two groups of patients did not significantly differ in GMFCS level, age at the time of the surgery, or patient gender. There was similar distribution in CP patterns in the standard and modified groups; spastic hemiplegia was the most prevalent form, followed by spastic diplegia and spastic paraplegia. Overall, better surgical success was achieved in patients with GMFCS levels I-III (100%, 94.8%, and 69.8%, respectively). SPOTT procedure failure was frequently noticed in patients with GMFCS level IV (90.9%). ConclusionThe modified SPOTT procedure demonstrated efficiency and safety in patients with equinovarus foot deformity due to CP during the long-term follow-up. Compared with the standard procedure, the newly modified SPOTT technique showed significantly better surgical outcome, irrespective of the patients' gender, age, initial GMFCS level, and CP type.

The efficacy of split tibial tendon transfers on functional gait outcomes for children and youth with cerebral palsy and spastic equinovarus foot deformities

“…equinovarus vs varus), 17 , 29 intervention (i.e. modified SPLATT vs standard SPLATT or SPLATT vs SPOTT), 13 , 15 and type of CP (i.e. hemiplegia vs diplegia).…”

“…Eight studies (205 feet) implemented the SPLATT intervention, 7 - 14 of which three studies were published in 2020 or, more recently, 7 - 9 implementing the SPLATT to Peroneus Brevis/Peroneus Tertius approach versus the SPLATT to cuboid approach (used in studies prior to 2015). Ten studies implemented SPOTT (353 feet), 4 , 5 , 12 , 13 , 15 , 17 , 29 , 37 - 39 with the majority reporting the SPOTT to Peroneus Brevis surgical approach. Out of these studies, two reported either SPLATT or SPOTT intervention groups depended on the clinical presentation, 12 , 13 and one had a subgroup combining both procedures during index operation (n = 3 feet).…”

“…Three studies reported use of above-knee casts for at least six weeks with periods of restricted weightbearing, 5 , 12 , 36 with nine reporting the use of below-knee casts and earlier weightbearing. 7 , 8 , 10 , 11 , 14 , 15 , 17 , 29 , 39 Four studies 4 , 5 , 13 , 37 described a combination of above- and below-knee casts. Follow-up times varied widely from one to 16 years, with seven studies 5 , 9 , 10 , 13 , 14 , 29 , 40 reporting outcomes at a mean of five years or more, and six studies over seven years post-surgery.…”

“… 7 , 8 , 10 , 11 , 14 , 15 , 17 , 29 , 39 Four studies 4 , 5 , 13 , 37 described a combination of above- and below-knee casts. Follow-up times varied widely from one to 16 years, with seven studies 5 , 9 , 10 , 13 , 14 , 29 , 40 reporting outcomes at a mean of five years or more, and six studies over seven years post-surgery. 5 , 9 , 10 , 13 , 29 , 40 …”

“… 4 , 9 By contrast, when the impairment is more within the stance phase of gait with the hindfoot in varus and equinus (and an overactive TP), a SPOTT to the peroneus brevis (or the lateral cuneiform) on the lateral side of the foot is indicated. 15 This is considered preferable to TP lengthening, to minimize altering the capacity of the muscle to produce power through range, an undesired product of lengthening. 4 , 5 , 13 To a large degree, the actions of TA and TP muscle activity will overlap due to the phenomenon of segmental linkage, and for this reason both gait analysis and electromyographic assessments provide valuable adjuncts for operative planning.…”