The use of the absorbable interference screw for a split anterior tibial tendon (SPLATT) transfer procedure

Interference screw versus suture button fixation for tibialis anterior tendon transfer: a biomechanical analysis

Tibialis anterior tendon (TAT) transfer to the lateral cuneiform is commonly utilized to treat dynamic supination for relapsed clubfoot deformity. Traditional suture button fixation (SBF) may lead to skin necrosis at the button/skin interface. While interference screw fixation (ISF) would mitigate this concern, this fixation method has not been investigated in clubfoot patients. This study aims to investigate the performance of ISF versus SBF for TAT transfer in a cadaveric model. Ten matched pairs of cadaveric feet were obtained. One of each matched specimen underwent TAT transfer to the lateral cuneiform using ISF and the other underwent TAT transfer using SBF. For each ISF specimen, the tension of the transferred TAT required to bring the ankle to neutral was measured. This tension was then applied to both matched specimens using an MTS machine. Tension dissipation was measured after a 20-minute interval. In specimens with SBF, a load cell was positioned between the plantar skin and suture button to determine plantar skin pressure at the time of initial tension application. Average tension necessary to achieve neutral dorsiflexion was 49.4 N. Average tension dissipation after 20 min was significantly less in the IFS group (20 N versus 23.6 N, P = 0.02). No fixation failures occurred in either group. Average plantar foot skin pressure was 196.5 mmHg at initial tension application, exceeding thresholds for tissue ischemia. ISF allows for tendon tensioning at forces beyond those expected to result in skin necrosis with SBF with less dissipation of tension over time.

Lateral Cuneiform Ossification and Tibialis Anterior Tendon Width in Children Ages 3 to 6: Implications for Interference Screw Fixation of Tibialis Anterior Tendon Transfers in Children

BACKGROUND

While the transfer of the tibialis anterior tendon (TAT) to the lateral cuneiform (LC) following serial casting has been used for nearly 60 years to treat relapsed clubfoot deformity, modern methods of tendon fixation remain largely unstudied. Interference screw fixation represents an alternative strategy that obviates concerns of plantar foot skin pressure-induced necrosis and proper tendon tensioning associated with button suspensory fixation. A better understanding of LC morphology in young children is a necessary first step in assessing the viability of this fixation technique. Therefore, the purpose of this investigation is to define LC morphology and TAT width in children aged 3 to 6 years.

METHODS

A retrospective radiographic review of 40 healthy pediatric feet aged 3 to 6 years who had either magnetic resonance imaging or computed tomography scans was performed at a single pediatric hospital. The length, width, and height of only the ossified portion of the LC were measured digitally using sagittal, coronal, and axial imaging. In addition, the maximal cross-sectional diameter of the TAT was measured at the level of the tibiotalar joint.

RESULTS

The average ossified LC width ranged from 8.5 mm in the 3-year-old cohort to 10.3 mm in 6-year-old children. Analysis of variance testing revealed no statistically significant difference in width between age groups. Average ossified LC length ranged from 13.5 mm in the 3-year-old cohort to 18.3 mm in 6-year-old children with statistically significant increases in age groups separated by 2 or more years. Significant differences in LC height, volume, and TAT diameter were demonstrated after analysis of variance testing. The TAT to ossified LC width ratio ranged from 44% to 53% across age groups.

CONCLUSIONS

The dimensions of the LC ossification center are large enough to allow interference screw fixation in children 3 to 6 years of age. Further studies are needed to investigate interference screw fixation performance in the pediatric clubfoot population.

LEVEL OF EVIDENCE

Level IV.

The Treatment of Recurrent Congenital Clubfoot

The Ponseti method for treatment of congenital clubfoot is well established and has been introduced in most pediatric orthopedic centers worldwide. However, reported rates of recurrence are largely variable and open joint surgery is still performed frequently, even in the age group younger than 6 years of age. Preventing recurrence and residual deformity can be achieved by strict adherence to the Ponseti method, ensuring and enforcing brace compliance, frequent follow-up, and early treatment of recurrence. This review discusses reasons for clubfoot recurrence, prevention of clubfoot recurrence, and the treatment of recurrent congenital clubfoot within the realm of the Ponseti method.

Split anterior tibialis tendon transfer to peroneus brevis for spastic equinovarus in children with hemiplegia

PURPOSE

The aim of this study is to report the safety and eff-cacy of soft-tissue surgery incorporating split transfer of tibi-alis anterior to peroneus brevis (SPLATT-PB) for children with hemiplegic spastic equinovarus.

METHODS

This was a retrospective case series of children and adolescents with spastic hemiplegia who had a novel combination of SPLATT-TB, intramuscular tenotomy of tibialis posterior and either spasticity management or gastrocsole-us lengthening as the index surgery. The principal outcome measures were changes in pain and difficulty with shoe wear and radiological parameters obtained from weight-bearing anteroposterior and lateral radiographs of the affected foot before and after surgery.

RESULTS

A total of 63 patients with symptomatic spastic equinovarus met the inclusion criteria. Mean age at surgery was 9.8 years (6 to 18) and the mean follow-up was seven years (range 3 to 10 years). Foot pain and problems with shoe wear improved after surgery. Seven radiological criteria showed a clinically and statistically significant improvement at follow-up, the majority being in the normal range. There were 11 surgical adverse events, all classified as Modified Cla-vien-Dindo Grade II. Three patients required further surgery for recurrent equinus, eight patients required further surgery for valgus deformities and four patients required bony surgery for residual varus deformities.

CONCLUSION

Soft-tissue surgery for spastic equinovarus was successful in the majority of children with spastic hemiplegia, particularly between ages eight and 12 years, resulting in a plantigrade, flexible foot with minimal pain or limitations in shoe-wear. Children younger than 8 years at index surgery were more prone to overcorrection into valgus. Children older than 12 years had persistent varus deformities requiring bony surgery.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Split Tibialis Anterior Tendon Transfer to The Peroneus Brevis or Tertius for the Treatment of Varus Foot Deformities in Children with Static Encephalopathy: A retrospective case series

INTRODUCTION

The study purpose was to determine the safety/efficacy of a split anterior tibialis tendon transfer (SPLATT) to the peroneus tertius or brevis in children with static encephalopathy and varus feet.

METHODS

A retrospective review of short- and long-term complications, change in ankle range of motion, strength, and gait kinematics. Predictors of postoperative varus or valgus were examined.

RESULTS

One hundred thirty-three patients were included (average age [SD] 10.3 [3.7]), with an average follow-up of 3.9 (3.4) years. Forefoot/hindfoot eversion range of motion improved (P ≤ 0.05), dorsiflexor strength was maintained or improved in 76.9% of patients, and dorsiflexion in swing phase was maintained. Complications occurred in 6 of 133 patients (4.5%) and included 1 transfer failure, 1 wound dehiscence, and four pressure areas from casts. Successful correction was achieved in 77% of patients. Later onset of recurrent varus (14.4%, 10.6% requiring revision surgery) and pes valgus (8.7%, 4.8% requiring revision surgery) occurred. The length of the follow-up predicted the development of the pes valgus (odds ratio 1.28, 95% CI 1.0 to 1.6).

DISCUSSION

SPLATT to the peroneus tertius or brevis is effective, and complications are rare. Subsequent valgus or recurrent varus deformities may occur, possibly requiring repeat surgery.

The split transfer of tibialis anterior tendon to peroneus tertius tendon for equinovarus foot in children with cerebral palsy

OBJECTIVE

The aim of this study was to analyze the results of the split anterior tibialis tendon transfer (SPLATT) to peroneus tertius (PT) for equinovarus foot deformity in children with cerebral palsy (CP).

METHODS

The medical records of 25 ambulatory CP patients (mean age: 8.7±3.2 years, range: 4-16 years) with equinovarus foot (33 feet), who underwent SPLATT to PT surgery between 2014 and 2016, were retrospectively reviewed. A senior surgeon performed all the surgical procedures. SPLATT was performed as part of a single-event multilevel surgery for the lower limb, and the concomitant procedures on the same extremity were recorded. The patients who required any additional foot or ankle surgery that could affect the clinical outcome (except heel cord lengthening) were excluded from the study. The Kling's College Criteria were used to evaluate the procedural outcome of the foot position and gait, and the associated complications were recorded.

RESULTS

The mean follow-up time was 28.8±5 months (range: 24-42 months). The postoperative Kling scores were excellent for 27 feet of the patients who had a plantigrade foot, without fixed or postural deformity, in a regular shoe, having no calluses; good for 5 cases for those who walked with less than 5° varus, valgus, or equinus posture of the hind foot, wearing regular shoes, having no callosities; and fair for 1 case for those who had recurrence of the deformity. There was only one wound detachment, which was treated with wound care and dressing. None of the patients had overcorrection, infection, or bone fracture.

CONCLUSION

The dynamic SPLATT to PT surgery for the management of the equinovarus foot deformities in the CP patients is a safe and less complicated surgical alternative with a good functional outcome. It is a safe and effective treatment method for the management of equinovarus foot deformities in CP.

LEVEL OF EVIDENCE

Level IV, Therapeutic study.

The Neuro-Orthopaedic Approach

Upper motor neuron disease or injury can lead to muscle spasticity or nonfunction throughout the body. Imbalance in muscle forces predisposes patients to development of functional deficiencies, contractures, pain, and poor hygiene. The approach to neuro-orthopaedic patients is by necessity multidisciplinary, because a variety of nonsurgical and surgical options are available. In evaluating each patient, surgeons must consider the extent and quality of any deformity, potential for improvement in function, the ability to alleviate pain, and potential for improvement in hygiene and cosmesis. Surgical techniques include tendon lengthenings, releases, transfers, osteotomies, and bony fusions.

Tibialis Anterior Tendon Transfer for Relapsing Idiopathic Clubfoot

INTRODUCTION

A relapsed idiopathic clubfoot can be effectively treated with transfer of the entire tibialis anterior tendon to the mid-dorsum of the foot following repeated manipulations and serial casts.

STEP 1 PREOPERATIVE PLANNING

Ensure that the foot has been adequately corrected for tendon transfer by performing both clinical and radiographic evaluation.

STEP 2 PREPARE THE PATIENT

Position the patient supine, induce general anesthesia, and perform a caudal block for postoperative pain management.

STEP 3 IDENTIFY AND RELEASE THE TIBIALIS ANTERIOR TENDON FROM ITS INSERTION

Identify the tibialis anterior tendon and release its insertion on the medial cuneiform and first metatarsal bones.

STEP 4 PREPARE THE TENDON AND SURROUNDING TISSUES FOR TRANSFER

Release obstructing tissues and prepare the freed tendon for lateral transfer to the mid-dorsum of the foot.

STEP 5 PREPARE THE LATERAL CUNEIFORM FOR TENDON TRANSFER AND FIXATION

Identify the lateral cuneiform with fluoroscopy and prepare it for transfer of the tibialis anterior tendon.

STEP 6 TRANSFER AND SECURE THE TENDON

Make a subcutaneous path, transfer the tendon, and secure it in the osseous tunnel of the lateral cuneiform.

STEP 7 POSTOPERATIVE CARE

We apply a long leg cast and restrict patients to non-weight-bearing for six weeks.

RESULTS

The tibialis anterior tendon transfer has been used to treat relapsing idiopathic clubfoot with great success for more than fifty years.IndicationsContraindicationsPitfalls & Challenges.

Spastic foot and ankle deformities: evaluation and treatment

Spastic foot and ankle deformities can occur from various causes and have profound effects on individuals and society. Presentations can vary clinically and a thorough clinical evaluation, potentially with a dynamic electromyogram, is essential to selecting the most appropriate treatment. Nonoperative treatments, such as orthotics, casting, oral medications, and nerve blocks, can be effective but surgery is indicated if they are no longer effective. Of the various operative procedures to treat this condition, split anterior tibialis tendon transfer and tendo Achilles lengthening are the most commonly performed. Multiple surgical options have been shown to be effective.

Nerve structures at risk in the plantar side of the foot during anterior tibial tendon transfer: a cadaver study

BACKGROUND

Anterior tibial tendon transfer is a common procedure for treatment of clubfoot recurrence. Fixation of the tendon usually includes passing the tendon through the lateral cuneiform. Drilling the bone and passing sutures through the plantar aspect of the foot may cause neurovascular damage.

METHODS

Anterior tibial tendon transfer was performed through the lateral cuneiform in twelve cadaveric limbs. Drill holes were made perpendicular to the lateral cuneiform surface (group A), made perpendicular to the weight-bearing surface (group B), inclined 15° in the frontal and sagittal planes (group C), or aimed at the middle of the plantar aspect of the foot (group D). Two unmodified Keith needles and two blunted Keith needles were each passed ten times per foot. A dissection was performed. The average distance from the drill hole to the nerve structures and the number of punctures of nerve structures were reported.

RESULTS

In group A, the drill hole was 1.7 mm from a medial plantar nerve branch and 5 mm from the nerve bifurcation. In group B, the hole was 0.3 mm from a branch of the lateral plantar nerve and 25.3 mm from the lateral plantar nerve bifurcation. The drill hole in group C was 1.7 mm from the lateral plantar nerve bifurcation. In group D, the drill direction resulted in an inclination of 22° in the frontal plane and 4° in the sagittal plane. The drill exited 7.7 mm from a medial plantar nerve branch and 4.3 mm from a lateral plantar nerve branch. The medial and lateral plantar nerve bifurcations were at a distance of 13 mm and 14.7 mm, respectively, from the drill hole in group D. Unmodified Keith needles punctured nerve structures twelve times in group A, twenty times in group B, six times in group C, and once in group D. Use of blunted Keith needles resulted in no nerve punctures.

CONCLUSIONS

When anchoring the transferred anterior tibial tendon in the lateral cuneiform for the treatment of clubfoot recurrence, the drill should be aimed at the middle of the plantar surface of the foot to minimize the risk of nerve damage. Passing the sutures with a blunt needle might prevent damage to nerves or vessels when anterior tibial tendon transfer to the lateral cuneiform is performed for the treatment of clubfoot recurrence.

The use of bioabsorbable screw in a split anterior tibial tendon transfer: a preliminary result

The split anterior tibial tendon transfer is a procedure commonly used to correct equinovarus deformity of the foot, primarily in children with spastic cerebral palsy. The procedure has been reported to yield satisfactory results; it can be combined with other soft tissue lengthening. Typically, the transferred tendon can be fixed by either button, staple, metal screw, or anchored into two bony tunnels. Occasionally, failure to maintain transferred tendon fixation may result from conventional surgical methods and therefore lead to undesirable results. The technique of using bioabsorbable interference screw has been proved to be effective in securing the graft as anterior cruciate ligament reconstruction in knee joint. To our knowledge, only few literatures have reported on the use of bioabsorbable screw in the treatment of tendon transfers around the foot. From 2004 to 2006, split anterior tibial tendon transfers with concomitant tendo-Achilles lengthening were applied to 13 patients (16 feet) who had a dynamic equinovarus deformity secondary to spastic cerebral palsy. Mean age at surgery was 8 years and the average follow-up period was 16 months (range, 12-28 months). A 7 x 23 mm cannulated bioabsorbable interference screw was used to fix the transferred tendon. Postoperatively, we used the rating system of Kling et al. to assess the clinical results. Our findings showed that there were 10 excellent, six good, and no poor results. All patients had improved gait at their latest follow-ups. At final follow-up, there was no graft failures or postoperative complications related to the bioabsorbable screw in our series. Although the study is based on a small number of cases, we suggest this technique is an additional armamentarium in fixation for tendon transfers in children's feet.

Fixation techniques for split anterior tibialis transfer in spastic equinovarus feet

Equinovarus of the foot is the most common lower extremity deformity following traumatic brain injury. We evaluated outcomes of the split anterior tibialis tendon transfer (SPLATT) for correction of equinovarus in 47 patients with hemiplegic traumatic brain injury and specifically studied differences in outcomes with two tendon fixation techniques. Seventeen patients constituting Group I underwent fixation with one technique and 30 constituting Group II had another technique. Patients in both groups had appropriate procedures based on dynamic electromyography and gait analyses. Both groups were demographically comparable. All 47 feet were corrected to plantigrade position. Thirty-six of 47 patients became brace-free at final followup. There was a notable decrease in the use of ambulatory aids and ambulatory status improved in both groups. There were three fixation-related complications in Group I and none in Group II. Surgical correction of the spastic equinovarus with SPLATT, in the appropriate patient, with or without associated tendon procedures helps to achieve and maintain correction, improves the ambulatory status of the patient, and eliminates the need for bracing in as much as 77% of patients. We recommend the Group II construct owing to the considerably lower complication rate.

Tenotomy and tendon transfer about the forefoot, midfoot and hindfoot

Tendon lengthening and transfer are essential surgical procedures for every foot and ankle surgeon to master, because they are useful in restoring balance and correcting flexible foot deformities. These techniques are even more useful in treating the high-risk patient, because they involve minimal soft-tissue injury and maximum preservation of vascularity. The primary goal of this article is to supplement the foot and ankle surgeon's options for treating static and dynamic foot deformities in the high-risk patient by discussing useful tendon lengthening and transfer procedures about the forefoot, midfoot, and hindfoot.

Surgery can reduce the nonoperative care associated with an equinovarus foot deformity

Equinovarus is the most common lower extremity deformity seen after a stroke. Despite its frequency, there are no specific guidelines in determining when surgery should be considered and for which patients it is appropriate. We evaluated the charges of nonsurgical and surgical treatments for equinovarus foot in 29 consecutive patients who underwent surgery for a unilateral equinovarus deformity after stroke. Twenty-six patients (seven males, 19 females) were available for followup. Mean patient age at the time of stroke was 48.2 years (range, 3-66 years). The average age at surgery was 54.7 years (range, 23-72 years), with a mean duration of nonsurgical treatment of 74.7 months. The minimum followup was 6 months following surgery (mean, 18.2 months; range, 6-48 months). Physical therapy accounted for 88% of nonoperative charges, with chemodenervation and orthotics accounting for 10% and 2%, respectively. Postoperatively, 19 patients were able to discontinue physical therapy compared with none preoperatively, and 17 discontinued orthotic use. Surgical correction of the equinovarus foot, in the appropriate patient, can decrease the use of nonoperative care for a patient who has had a stroke. We recommend surgery be considered earlier when an equinovarus deformity persists after the period of spontaneous neurologic recovery.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Bioabsorbable fixation in foot and ankle

Bioabsorbable implants are playing an increasing role in the surgical management of foot and ankle pathologies. Current technology allows implants to have acceptably comparable strength and pull-out characteristics to metallic implants. The advantages include elimination of secondary surgeries, biodegradability of implants placed across mobile articular surfaces, as well as acceptable biocompatibility and resorption properties to limit historical complication concerns.

The principles of interference screw fixation: application to foot and ankle surgery

Based on the success of the anterior cruciate ligament model, interference screw fixation is now being applied to a wide variety of orthopedic conditions that require the fixation of tendon or ligament to bone. The primary focus of this article is to present the principles of interference screw fixation. By understanding the principles of interference screw fixation, the foot and ankle surgeon will be able to apply this fixation technique to a wide variety of surgical applications for tendon transfers or ligament repairs. The surgical technique, history, principles of fixation, studies of fixation strength, tissue healing, and foot and ankle indications are reviewed. A modified Girdlestone digital flexor tendon transfer procedure description is included to illustrate how interference screw techniques may be applied to foot surgery.