Split Tendon Transfer Research Articles

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

To systematically review the efficacy of split tendon transfer surgery on gait-related outcomes for children and adolescents with cerebral palsy (CP) and spastic equinovarus foot deformity. Five databases (CENTRAL, CINAHL, PubMed, Embase, Web of Science) were systematically screened for studies investigating split tibialis anterior or split tibialis posterior tendon transfer for spastic equinovarus foot deformity, with gait-related outcomes (published pre-September 2022). Study quality and evidence were assessed using the Methodological Index for Non-Randomized Studies, the Risk of Bias In Non-Randomized Studies of Interventions, and the Grading of Recommendations Assessment, Development and Evaluation. Overall, 17 studies (566 feet) were included: 13 studies used clinical grading criteria to report a postoperative 'success' of 87% (75% to 100%), 14 reported on orthotic use with 88% reduced postoperative use, and one study reported on ankle kinematics improvements. Ten studies reported post-surgical complications at a rate of 11/390 feet (2.8%), but 84 feet (14.8%) had recurrent varus (68 feet, 12%) or occurrence of valgus (16 feet, 2.8%). Only one study included a patient-reported outcome measure (pain). Split tendon transfers are an effective treatment for children and youth with CP and spastic equinovarus foot deformities. Clinical data presented can be used for future study designs; a more standardized functional and patient-focused approach to evaluating outcomes of surgical intervention of gait may be warranted.

Treatment of spastic varus/ equinovarus foot with split-tendon transfers in cerebral palsy: How does it affect the hindfoot motion?

IntroductionThe flexible spastic varus foot in cerebral palsy is commonly corrected by split-tendon transfer of tibialis anterior or tibialis posterior. These tendon transfers are said to preserve hindfoot motion, which is until now not been proven. Therefore, the aim of the study was to show the hindfoot motion following split-tendon transfer in comparison to a midtarsal arthrodesis. Materials and methodsA retrospective study was done on patients with flexible spastic varus foot in cerebral palsy who underwent a combined split-tendon transfer of tibialis anterior and posterior. Patients with a rigid foot deformity underwent a midfoot arthrodesis. These children and normal children served as controls. An instrumented gait analysis was done in all patients before and at follow-up. A statistical analysis was done using 2-factor ANOVA with repeated measures on time. ResultsThirteen children underwent a combined split-tendon transfers of tibialis anterior and posterior muscles and 14 children midtarsal arthrodesis. The mean follow-up was 2.4 (SD=0.8) years for flexible varus foot and 1.9 (SD=0.7) years for rigid foot deformity. The preoperative hindfoot range of motion in eversion-inversion was 54% and 49% of TD controls in flexible varus foot and rigid foot deformity respectively. At follow-up, it reduced further to 45% and 42% of TD controls in the respective groups. ConclusionBoth flexible and rigid hindfoot deformity reduced the hindfoot motion. However following surgery, the hindfoot motion reduced further and was identical in both groups independent of the type of surgery. This indicates a tenodesis-effect of split-tendon transfers on the hindfoot.

Split versus full tibialis anterior tendon transfer in treatment of residual dynamic supination in treated idiopathic clubfoot by Ponseti method

Background Dynamic supination is a common sequelae following successful nonoperative treatment of clubfoot with the Ponseti technique. It is resulted from a strong tibialis anterior muscle and weak antagonists, particularly the peroneal and tibialis posterior muscles. Tendon-balancing procedure is the most reasonable solution. Use of tibialis anterior tendon transfer (TATT) in recurrent clubfoot deformities has been described since 1940. Patients and methods Through this study, we compare the results of split versus full TATT in the treatment of residual dynamic supination in treated idiopathic clubfoot by Ponseti method. Patients were divided into two groups. The first group (nine patients with 10 feet) (group I) consists of the patients who were managed with split tendon transfer and the second group (nine patients with 10 feet) (group II) consists of the patients who managed with full tendon transfer. Garceau and Palmer’s clinical criteria and a grading system proposed by Thompson and colleagues were used for evaluation of the results of tendon transfer either split or full. Results A total of 18 children (13 males and five females) were involved in this study. The average of the age of the children in group I was 4.3 years and in group II was 4 years at the time of surgery. According to Garceau and Palmer’s clinical criteria, in group I, the preoperative ratings of 10 feet were as follows: four feet were good and six feet were fair, with scores of 3 points and 2 points, respectively. The postoperative ratings were five feet were excellent and five feet were good, with scores of 4 points and 3 points, respectively, with a statistically significant improvement (P 0.05). According to the grading system proposed by Thompson and colleagues for restoration of muscle balance, in group I, eight feet achieved good results and two feet achieved fair results, whereas in group II, seven feet achieved good result and three feet achieved fair results. In comparing the results of both groups, we found there was no statistically significant relation (P>0.05). Conclusion TATT is an excellent method of correcting residual dynamic clubfoot deformity and there is no significant difference in the results by either full transfer or split transfer, and the surgeon’s preference plays a major role in selection of the procedure.

Estudio de las unidades neurofuncionales del flexor carpi ulnaris y su utilidad en las transferencias tendinosas

ObjectivesThe purpose of this paper is to document the intramuscular innervation of flexor carpi ulnaris (FCU), its vascularisation, and its subsequent organisation in neurofunctional units. The relevance of these neurofunctional units in the performance of split-tendon transfers of this muscle is also discussed. Although this idea has already been put into practice in some surgical centres, there are few published works in the literature which graphically show its underlying anatomical basis. Material and methodsSix FCU specimens were extracted from human cryopreserved cadavers and stained following Sihler's technique. In order to study the vascularization, 5 of them were also injected with coloured latex through the brachial artery. ResultsIn all of the specimens, each of the two heads of the FCU corresponded to a neurofunctional unit, and was independently innervated (Taylor's type III pattern). The 5 injected specimens belonged to either type II or type III of the Mathes-Nahai classification. ConclusionsThe divisibility of the muscle into two independently vascularised and innervated neurofunctional units allows two tendons to be obtained from the donor muscle, which are then transferable to two different muscles, thus optimising the transfer.

A comprehensive analysis of pectoralis major transfer for long thoracic nerve palsy

In the treatment of long thoracic nerve palsy with pectoralis major transfer, it remains unknown whether direct transfer of the pectoralis to the scapula or indirect transfer with an interpositional graft provides superior outcomes. A 3-tiered study was performed to gain a comprehensive understanding. (1) A survey of the membership of the American Shoulder and Elbow Surgeons (ASES) was conducted to reach a Level V consensus. (2) A systematic review was conducted to identify all series evaluating direct and indirect transfer of the pectoralis major tendon to create a Level IV consensus. (3) A retrospective review was performed to provide Level III evidence. (1) Surgeons were evenly split between whole and split tendon transfers, direct and indirect transfers, and graft types. More experienced surgeons were more likely to prefer an indirect transfer. (2) Analysis of 10 Level IV studies (131 shoulders) revealed that patients who underwent indirect transfer were significantly more likely to develop recurrent winging (P=.009) and had lower active forward elevation (P<.001) and ASES scores (P=.0016). (3) Twenty-four patients were included in our retrospective review with a mean follow-up of 4.3years (77% follow-up), of whom 14 underwent indirect transfer and 10 underwent direct transfer. There were no significant differences in recurrence of winging, range of motion, or ASES scores. Level V and III evidence suggests that there is no functional difference between direct and indirect transfer. Level IV evidence must be interpreted with caution.

Architectural properties of the neuromuscular compartments in selected forearm skeletal muscles.

The purposes f this study were to (i) explore the possibility of splitting the selected forearm muscles into separate compartments in human subjects; (ii) quantify the architectural properties of each neuromuscular compartment; and (iii) discuss the implication of these properties in split tendon transfer procedures. Twenty upper limbs from 10 fresh human cadavers were used in this study. Ten limbs of five cadavers were used for intramuscular nerve study by modified Sihler's staining technique, which confirmed the neuromuscular compartments. The other 10 limbs were included for architectural analysis of neuromuscular compartments. The architectural features of the compartments including muscle weight, muscle length, fiber length, pennation angle, and sarcomere length were determined. Physiological cross-sectional area and fiber length/muscle length ratio were calculated. Five of the selected forearm muscles were ideal candidates for splitting, including flexor carpi ulnaris, flexor carpi radials, extensor carpi radialis brevis, extensor carpi ulnaris and pronator teres. The humeral head of pronator teres contained the longest fiber length (6.23 ± 0.31 cm), and the radial compartment of extensor carpi ulnaris contained the shortest (2.90 ± 0.28 cm). The ulnar compartment of flexor carpi ulnaris had the largest physiological cross-sectional area (5.17 ± 0.59 cm(2)), and the ulnar head of pronator teres had the smallest (0.67 ± 0.06 cm(2)). Fiber length/muscle length ratios of the neuromuscular compartments were relatively low (average 0.27 ± 0.09, range 0.18-0.39) except for the ulnar head of pronator teres, which had the highest one (0.72 ± 0.05). Using modified Sihler's technique, this research demonstrated that each compartment of these selected forearm muscles has its own neurovascular supply after being split along its central tendon. Data of the architectural properties of each neuromuscular compartment provide insight into the 'design' of their functional capability. In addition to improving our understanding of muscle anatomy and function, elucidation of forearm neuromuscular compartments architecture may ultimately provide information useful for selection of muscle subdivisions used in tendon transfer.

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

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.

Lateral and Medial Plantar Pressures after Split versus Whole Anterior Tibialis Tendon Transfer

If whole and split transfer of the anterior tibialis tendon (SPLATT) do not differ in balancing the forefoot, whole tendon transfer would provide a simpler alternative as part of treatment of an equinovarus deformity. We hypothesized that no significant differences in percent plantar lateral forefoot pressures would be observed between split and whole tendon transfer. We used a spastic model to test the hypothesis that overcorrection would not occur with whole tendon transfer. In ten specimens from five lower extremity matched pairs, a SPLATT was anchored to the cuboid. After loading, simulated whole tendon transfer to the lateral cuneiform was done. Normal loading was Achilles, 250 N, tibialis anterior, 200 N, peroneals/tibialis posterior, 142 N; and spastic loading was Achilles, 500 N, tibialis anterior, 400 N, peroneals/tibialis posterior, 142 N. Pressure data were collected for both normal and spastic conditions. Percent of forefoot pressure was calculated for the lateral and medial sector. Percent lateral pressure was slightly lower after whole tendon transfer (normal, p < 0.01; spastic, p < 0.01). This difference was not clinically important. Medial pressure did not differ in the spastic versus the normal model after split or whole tendon transfer. Whole and split anterior tibialis tendon transfer both resulted in a balanced forefoot. Neither whole tendon nor split tendon transfer resulted in overcorrection in a simulated spastic model. Whole tendon transfer may be an effective and simpler alternative to SPLATT for unloading the lateral forefoot in both a normal and a spastic foot.

Effect of Attachment Site and Routing Variations in Split Tendon Transfer of Tibialis Posterior

Effect of Attachment Site and Routing Variations in Split Tendon Transfer of Tibialis Posterior

Effect of attachment site and routing variations in split tendon transfer of tibialis posterior.

Spastic equinovarus is a condition that commonly affects the gait of children with cerebral palsy. Split tendon transfers of the tibialis posterior (TP) are often performed to eliminate the excessive hindfoot inversion present in equinovarus. TP muscle moment arms were computed before and after three variations of split TP tendon transfer to assess the effectiveness of each. The three surgeries tested were (1) the original split TP transfer to the distal peroneus brevis tendon routing behind the lateral malleolus; (2) an attachment variation in which the transferred tendon half was attached to the proximal peroneus brevis tendon rather than to the distal site; and (3) a routing variation in which the transferred tendon half was passed through a window in the interosseous membrane and attached to the distal peroneus brevis tendon. Tendon tension was controlled for in these experiments because improper tensioning is often cited as a reason for poor outcomes. All three surgeries significantly reduced the ability of TP to invert the hindfoot, thus eliminating a potential deforming force, but the reduction following interosseous routing was significantly less than that found for the other two transfer procedures. Routing through the interosseous membrane also reduced the ability of the TP to plantarflex the foot, but ankle actions were preserved following the other two surgeries. Routing through the interosseous membrane to an anterior attachment site resulted in a muscle with minimal potential to create or resist action about the ankle joint. Similar moment arms were measured when the attachment site on the peroneus brevis tendon was located either proximally or distally, suggesting that this choice does not appear to significantly affect the mechanical outcome.

Effects of tensioning errors in split transfers of tibialis anterior and posterior tendons.

Split transfers of the tibialis anterior and posterior tendons are commonly performed to address hindfoot varus deformities in patients with cerebral palsy, stroke, or brain injury. Poor outcomes from these procedures are often attributed to a failure to tension the transferred tendon properly, but the mechanical effects of this aspect of the procedure have not been quantified, to our knowledge. The purpose of the present study was to use a cadaver model to examine changes in the actions of these muscles that occur when the tensions in the halves of the split tendon are intentionally balanced or unbalanced to varying degrees. Tendon excursion was measured in seven cadaveric specimens before and after split tendon transfer with experimentally controlled tensions in the halves of the split tendon. The muscle moment arm, a quantitative indicator of the action of a muscle about a joint axis, was calculated as the derivative of tendon excursion with respect to the subtalar joint angle. The tibialis anterior had an eversion moment arm with the subtalar joint in a neutral position following surgery, but the tibialis posterior had virtually no action in the neutral position. Following the split transfers with ideally balanced tension, subtalar joint rotations of >5 degrees strongly influenced the moment arm of the tibialis posterior (p < 0.0002), indicating that its action depends on the position of the hindfoot. The moment arm of the tibialis anterior, however, was influenced only by rotations of >/=20 degrees (p > 0.1741 for each angle pair comparison of <20 degrees ). Moment arms were generally insensitive to imbalances in tension between the medial and lateral tendon halves; significant differences in the moment arm (p < 0.05), compared with that in the balanced condition, were seen only when one half was slack or nearly so. These results suggest that it is possible for a split tendon transfer to be successful over a large range of tensionings. Split transfer of the tibialis posterior tendon produced the desired mechanical outcome in that the tibialis posterior had an eversion moment arm when the foot was inverted and an inversion moment arm when the foot was everted. Split transfer of the tibialis anterior to the cuboid, however, produced a muscle that consistently functioned as an everter regardless of the position of the hindfoot.

Long-Term Follow-up of Surgery for Equinovarus Foot Deformity in Children With Cerebral Palsy

The factors associated with failed operative intervention in the treatment of equinovarus foot deformity in children with cerebral palsy (CP) were evaluated after long-term follow-up. One hundred eight children with CP who had surgery on the posterior tibialis tendon (split tendon transfer, intramuscular lengthening, or Z-lengthening) on 140 feet were reviewed at a mean age of 16.8 years with 7.3 years of follow-up. The surgery was considered a failure when a 10 degrees or greater varus or valgus hindfoot deformity was present or if an additional operative intervention was required or planned. Involvement of CP, age at operation, and preoperative status of ambulation were significant factors in the outcome of the surgery. Hemiplegic patients demonstrated the best results, regardless of age or surgical procedure. Seventy-five percent of diplegic and quadriplegic patients who were younger than 8 years or who were not capable of community ambulation failed operative intervention, and surgery on the posterior tibialis tendon is not recommended in this group of patients.

Changes in muscle moment arms following split tendon transfer of tibialis anterior and tibialis posterior.

Moment arms of tibialis anterior (TA) and tibialis posterior (TP) about the subtalar and talocrural joint axes were measured in anatomic specimens both before and after split tendon transfers. These procedures are commonly performed to correct hindfoot varus, a gait deformity that is often seen in patients with cerebral palsy, stroke, and brain injury. Split tendon transfer significantly reduced the inversion moment arms of tibialis anterior and tibialis posterior at all subtalar joint angles except for the most everted position in the case of TA. Changes in subtalar joint moment arms produced by split tendon transfer, especially those seen in TA, were variable, suggesting that the procedure may be susceptible to technical errors, especially related to balancing tensions in the medial and lateral tendon halves. Talocrural joint moment arms of both muscles were preserved following split tendon transfer. This study presents the first measurements of the moment arms of split transferred muscles. These characterizations of the mechanics of split tendon transfer will aid in the planning and assessment of these procedures.

Split anterior tibial tendon transfer for recurrent idiopathic clubfoot

Complete anterior tibial tendon transfer for the treatment of the recurrent clubfoot was first described by Garceau.1 Split anterior tibial tendon transfer has been described in the treatment of the spastic equinovarus foot deformity in both the adult and child.2–4 To our knowledge, split tibialis anterior tendon transfer has not been reported before as an isolated treatment of the recurrent idiopathic clubfoot. A split tendon transfer is thought to have a lower risk of over-correction, although this has never been proven in comparative studies. We report our results using a split tendon transfer for the treatment of the recurrent clubfoot. We assess outcome clinically, pedobarographically and ultimately whether the patient required further surgery.

Biomechanical study of tibialis anterior tendon transfer.

The tibialis anterior tendon transfer has been used in the treatment of recurrent congenital clubfoot and paralytic equinovarus foot deformities in cerebral palsy. This study attempts to determine the optimal site of tibialis anterior tendon insertion for ankle and foot motion and to compare the split and whole tendon transfer. Ten fresh normal anatomic leg specimens were used. The lateral half of the tibialis anterior tendon was detached from its insertion, passed beneath the extensor retinaculum, and anchored to the appropriate tarsal bone by a barbed staple. Tension was applied, and ankle and foot motions were measured. The experiment was done by anchoring the tendon to the tarsal bones along the axis of the second metatarsal and serially through to the axis of the fifth' metatarsal. The entire experiment was repeated using the whole tibialis anterior tendon. For split tendon transfer, insertion onto the fourth metatarsal axis was the most effective route; it produced maximal dorsiflexion with minimal supination and pronation. For whole tendon transfer, the ideal site of insertion was along the third metatarsal axis. However, the difference between the average maximum dorsiflexion achieved by the split tendon transfer and that of total tendon transfer is not statistically significant.

Correction of hallux varus via split tendon transfer

The split tendon transfer is introduced as an additional procedure for the correction of hallux varus. More clinical and statistical evaluations are required to fully appreciate its potential benefits.

The Cincinnati Incision for the Split Posterior Tibial Tendon Transfer

The split posterior tendon transfer has been effective in correcting equinovarus deformity in children with cerebral palsy. The original report of this procedure described a four incision approach. We have modified the technique by substituting the single transverse, Cincinnati incision, which permits better visual and physical access to the operative field and has no major disadvantages.

SPLIT TENDON TRANSFER

SPLIT TENDON TRANSFER