Role of the peroneal tendons in the production of the deformed foot with posterior tibial tendon deficiency

Peroneus Brevis to Longus Tendon Transfer in the Treatment of Flexible Progressive Collapsing Foot Deformity: A Cadaveric Study

BACKGROUND

Although operative treatment of the flexible progressive collapsing foot deformity (PCFD) remains controversial, correction of residual forefoot varus and stabilization of the medial column are important components of reconstruction. A peroneus brevis (PB) to peroneus longus (PL) tendon transfer has been proposed to address these deformities. The aim of our study was to determine the effect of an isolated PB-to-PL transfer on medial column kinematics and plantar pressures in a simulated PCFD (sPCFD) cadaveric model.

METHODS

The stance phase of level walking was simulated in 10 midtibia cadaveric specimens using a validated 6-degree of freedom robot. Bone motions and plantar pressure were collected in 3 conditions: intact, sPCFD, and after PB-to-PL transfer. The PB-to-PL transfer was performed by transecting the PB and advancing the proximal stump 1 cm into the PL. Outcome measures included the change in joint rotation of the talonavicular, first naviculocuneiform, and first tarsometatarsal joints between conditions. Plantar pressure outcome measures included the maximum force, peak pressure under the first metatarsal, and the lateral-to-medial forefoot average pressure ratio.

RESULTS

Compared to the sPCFD condition, the PB-to-PL transfer resulted in significant increases in talonavicular plantarflexion and adduction of 68% and 72%, respectively, during simulated late stance phase. Talonavicular eversion also decreased in simulated late stance by 53%. Relative to the sPCFD condition, the PB-to-PL transfer also resulted in a 17% increase (P = .045) in maximum force and a 45-kPa increase (P = .038) in peak pressure under the first metatarsal, along with a medial shift in forefoot pressure.

CONCLUSION

The results from this cadaver-based simulation suggest that the addition of a PB-to-PL transfer as part of the surgical management of the flexible PCFD may aid in correction of deformity and increase the plantarflexion force under the first metatarsal.

CLINICAL RELEVANCE

This study provides biomechanical evidence to support the addition of a PB-to-PL tendon transfer in the surgical treatment of flexible PCFD.

Review of Classification Systems for Adult Acquired Flatfoot Deformity/Progressive Collapsing Foot Deformity and the Novel Development of the Triple Classification Delinking Instability/Deformity/Reactivity and Foot Type

Background: Classifications of AAFD/PCFD have evolved with an increased understanding of the pathology involved. A review of classification systems helps identify deficiencies and respective contributions to the evolution in understanding the classification of AAFD/PCFD. Methods: Using multiple electronic database searches (Medline, PubMed) and Google search, original papers classifying AAFD/PCFD were identified. Nine original papers were identified that met the inclusion criteria. Results: Johnson's original classification and multiple variants provided a significant leap in understanding and communicating the pathology but remained tibialis posterior tendon-focused. Drawbacks of these classifications include the implication of causality, linearity of progression through stages, an oversimplification of stage 2 deformity, and a failure to understand that multiple tendons react, not just tibialis posterior. Later classifications, such as the PCFD classification, are deformity-centric. Early ligament laxity/instability in normal attitude feet and all stages of cavus feet can present with pain and instability with minor/no deformity. These may not be captured in deformity-based classifications. The authors developed the 'Triple Classification' (TC) understanding that primary pathology is a progressive ligament failure/laxity that presents as tendon reactivity, deformity, and painful impingement, variably manifested depending on starting foot morphology. In this classification, starting foot morphology is typed, ligament laxities are staged, and deformity is zoned. Conclusions: This review has used identified deficiencies within classification systems for AAFD/PCFD to delink ligament laxity, deformity, and foot type and develop the 'Triple classification'. Advantages of the TC may include representing foot types with no deformity, defining complex secondary instabilities, delinking foot types, tendon reactivity/ligament instability, and deformity to represent these independently in a new classification system. Level of Evidence: Level V.

Posterior Tibial Tendon Transfer for the Correction of Drop Foot

BACKGROUND

Drop foot is a crippling condition that often requires surgical intervention to restore functional dorsiflexion. Although transfer of the posterior tibial (PT) tendon has been well described for the treatment of drop foot, there is no consensus on whether tendon transfers affecting the ankle joint sufficiently restore functional status for daily activities. In addition, most studies have focused on drop foot caused by peripheral nerve disorders. The purpose of this study was to evaluate the functional outcomes and patient satisfaction following PT tendon transfer for the correction of drop foot resulting from both peripheral and central neurologic causes.

METHODS

Patients with drop foot who underwent a PT tendon transfer were followed for a minimum of 1 year and investigated retrospectively. Outcome measures included the American Orthopaedic Foot & Ankle Society ankle and hindfoot scoring system, a patient satisfaction questionnaire, postoperative ankle range of motion, and postoperative ambulatory status.

RESULTS

We evaluated 15 feet in 14 patients at a median follow-up of 50 months. The median postoperative American Orthopaedic Foot & Ankle Society ankle and hindfoot score was 85.0. Thirteen patients (92.9%) reported that they would undergo the procedure again. The median postoperative passive ankle dorsiflexion was 5.0°, and the median postoperative passive ankle plantarflexion was 30.0°. Thirteen patients (92.9%) were able to ambulate postoperatively. Ten (71.4%) ambulated without the use of an ankle-foot orthosis (AFO), and three (21.4%) ambulated with the use of an AFO. Overall, orthoses were able to be discontinued in 73.3% of the cases.

CONCLUSIONS

Our results suggest that the PT tendon transfer is an effective procedure for the treatment of drop foot that can improve the patient's functional status and ability to ambulate. The majority of patients were able to discontinue the use of their AFO postoperatively.

Treatment approach to isolated common peroneal nerve palsy by mechanism of injury: Systematic review and meta-analysis of individual participants' data

BACKGROUND

We reviewed the individual participant data of patients who sustained isolated common peroneal nerve (CPN) injuries resulting in foot drop. Functional results were compared between eight interventions for CPN palsies to determine step-wise treatment approaches for the underlying mechanisms of nerve injury.

METHODS

PubMed, Embase, Cochrane Library, Web of Science, Scopus, and CINAHL databases were searched. PRISMA-IPD and Cochrane guidelines were followed in the data search. Eligible patients sustained isolated CPN injuries resulting in their foot drop. Patients were stratified by mechanisms of nerve injury, ages, duration of motor symptoms, and nerve defect/zone of injury sizes, and were compared by functional results (poor = 0, fair = 1, good = 2, excellent = 3), using meta-regression between interventions. Interventions evaluated were primary neurorrhaphy, neurolysis, nerve grafts, partial nerve transfer, neuromusculotendinous transfer, tendon transfer, ankle-foot orthosis (AFO), and arthrodesis.

RESULTS

One hundred and forty-four studies included 1284 patients published from 1985 through 2020. Transection/Cut: Excellent functional results following tendon transfer (OR: 126, 95%CI: 6.9, 2279.7, p=0.001), compared to AFO. Rupture/Avulsion: Excellent functional results following tendon transfer (OR: 73985359, 95%CI: 73985359, 73985359, p<0.001), nerve graft (OR: 4465917, 95%CI: 1288542, 15478276, p<0.001), and neuromusculotendinous transfer (OR: 42277348, 95%CI: 3001397, 595514030, p<0.001), compared to AFO. Traction/Stretch: Good functional results following tendon transfer (OR: 4.1, 95%CI: 1.17, 14.38, p=0.028), compared to AFO. Entrapment: Excellent functional results following neurolysis (OR: 4.6, 95%CI: 1.3, 16.6, p=0.019), compared to AFO.

CONCLUSIONS

Functional results may be optimized for treatments by the mechanism of nerve injury. Transection/Cut and Traction/Stretch had the best functional results following tendon transfer. Rupture/Avulsion had the best functional results following tendon transfer, nerve graft, or neuromusculotendinous transfer. Entrapment had the best functional results following neurolysis.

Surgical Management of Musculotendinous Balance in the Progressive Collapsing Foot Deformity: The Role of Peroneal and Gastrocnemius Contracture

Surgical treatment of progressive collapsing foot deformity (PCFD) relies on understanding the dynamic and deforming musculotendinous structures that contribute to hindfoot valgus, forefoot abduction, forefoot varus, and collapse or hypermobility of the medial column. Equinus commonly is seen in PCFD and consideration should be given to isolated gastrocnemius or Achilles lengthening. Although transfer of the flexor digitorum longus tendon is performed in PCFD attributed to dysfunction and pathology of the posterior tibialis tendon (PTT), retention of PTT is an area for further research. The peroneus brevis, which contributes to hindfoot imbalance in chronic cases, is a possible component of tendon rebalancing.

Orthopedic Surgical Foot Management in Hansen Disease

Hansen disease remains a common problem worldwide with 750,000 new cases diagnosed each year. Nerve injury is a central feature of the pathogenesis because of the unique tendency of Mycobacterium leprae to invade Schwann cells and the peripheral nervous system, that can be permanent and develop into disabilities. The orthopedic surgeon has an important role in the management of neuropathy, performing surgical release of the tibial and common peroneal nerves in potentially constricting areas, thus providing a better environment for nerve function. In cases of permanent loss of nerve function with drop foot, specific tendon transfers can be used.

Dynamic correction for forefoot varus in stage II-A adult flatfoot: Technique tip

Posterior tibial tendon dysfunction (PTTD) is a progressive disorder and a common cause of adult acquired flatfoot deformity, and forefoot varus is a frequent component in advanced cases. The author proposes peroneus brevis-to-longus transfer as an additional step to correct the forefoot varus component of stage II-A posterior tibial tendon dysfunction. We have performed this dynamic correction of forefoot varus in 12 patients at our institution, and observed promising clinical and radiographic improvement. It is a soft tissue procedure that avoids additional incisions and represents a favorable alternative to more demanding techniques, such as osteotomy or arthrodesis.

Functional Outcomes Following Anterior Transfer of the Tibialis Posterior Tendon for Foot Drop Secondary to Peroneal Nerve Palsy

BACKGROUND

This retrospective comparative study reports the practical function in daily and sports activities after tibialis posterior tendon transfer for foot drop secondary to peroneal nerve palsy.

METHODS

Seventeen patients were followed for a minimum of 3 years after tibialis posterior tendon transfer for foot drop secondary to peroneal nerve palsy. Matched controls were used to evaluate the level of functional restoration. Functional evaluations included American Orthopaedic Foot & Ankle Society (AOFAS) scores, Foot and Ankle Outcome Score (FAOS), Foot and Ankle Ability Measure (FAAM) scores, and isokinetic muscle strength test. Radiographic evaluation for the changes of postoperative foot alignment included Meary angle, calcaneal pitch angle, hindfoot alignment angle, and navicular height.

RESULTS

Mean AOFAS, FAOS, and FAAM scores significantly improved from 65.1 to 86.2, 55.6 to 87.8, and 45.7 to 84.4 points at final follow-up, respectively. However, all functional evaluation scores were significantly lower as compared to the control group ( P < .001). Mean peak torque (60 degrees/sec) of ankle dorsiflexors, plantarflexors, invertors, and evertors at final follow-up were 7.1 (deficit ratio of 65.4%), 39.2, 9.8, and 7.3 Nm, respectively. These muscle strengths were significantly lower compared to the control group ( P < .001). No significant differences in radiographic measurements were found, and no patients presented with a postoperative flat foot deformity. One patient (5.9%) needed an ankle-foot orthosis for occupational activity.

CONCLUSIONS

Anterior transfer of the tibialis posterior tendon appears to be an effective surgical option for paralytic foot drop secondary to peroneal nerve palsy. Although restoration of dorsiflexion strength postoperatively was about 33% of the normal ankle, function in daily activities and gait ability were satisfactorily improved. In addition, tibialis posterior tendon transfer demonstrated no definitive radiographic or clinical progression to postoperative flat foot deformity at intermediate-term follow-up.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Unique Case of Posterior Tibial Tendon Dysfunction After Stingray Strike

BACKGROUND

Posterior tibial tendon dysfunction is a common cause of adult acquired flatfoot deformity. The cause of posterior tibial tendon dysfunction is often multifactorial and may include repetitive microtrauma, poor blood supply to the tendon, and, rarely, traumatic rupture.

CASE DESCRIPTION

We present the case of a 69-year-old male with posterior tibial tendon dysfunction secondary to a stingray injury that occurred directly into the posterior tibial tendon. This injury led to an acquired adult flatfoot deformity that ultimately required surgical reconstruction. At the time of surgery, the posterior tibial tendon was severely degenerative at the site of skin penetration.

LITERATURE REVIEW

Previous case reports of stingray injury describe full-thickness skin penetration with a subsequent inflammatory response and large zone of necrobiosis. This is the first reported case of stingray trauma and envenomation directly into tendon with subsequent tendon dysfunction.

CLINICAL RELEVANCE

There are thousands of stingray injuries in the United States annually. Injuries vary in severity depending on the type of stingray, size of stingray, and depth and location of injury. For certain injuries, such as direct penetration into tendon, early irrigation and debridement may limit subsequent deficits caused by progressive tendon dysfunction.

LEVELS OF EVIDENCE

Therapeutic, Level IV: Case study.

Outcomes of the Bridle Procedure for the Treatment of Foot Drop

BACKGROUND

The purpose of this study was to determine the clinical outcomes and objective measures of function that can be expected for patients following the Bridle procedure (modification of the posterior tibial tendon transfer) for the treatment of foot drop.

METHODS

Nineteen patients treated with a Bridle procedure and 10 matched controls were evaluated. The Bridle group had preoperative and 2-year postoperative radiographic foot alignment measurements and completion of the Foot and Ankle Ability Measure. At follow-up, both groups were tested for standing balance (star excursion test) and for ankle plantarflexion and dorsiflexion isokinetic strength, and the American Orthopaedic Foot & Ankle Society and Stanmore outcome measures were collected only on the Bridle patients.

RESULTS

There was no change in radiographic foot alignment from pre- to postoperative measurement. Foot and Ankle Ability Measure subscales of activities of daily living and sport, American Orthopaedic Foot & Ankle Society, and Stanmore scores were all reduced in Bridle patients as compared with controls. Single-limb standing-balance reaching distance in the anterolateral and posterolateral directions were reduced in Bridle participants as compared with controls (P < .03). Isokinetic ankle dorsiflexion and plantarflexion strength was lower in Bridle participants (2 ± 4 ft·lb, 44 ± 16 ft·lb) as compared with controls (18 ± 13 ft·lb, 65 ± 27 ft·lb, P < .02, respectively). All Bridle participants reported excellent to good outcomes and would repeat the operation. No patient wore an ankle-foot orthosis for everyday activities.

CONCLUSION

The Bridle procedure was a successful surgery that did not restore normal strength and balance to the foot and ankle but allowed individuals with foot drop and a functional tibialis posterior muscle to have significantly improved outcomes and discontinue the use of an ankle-foot orthosis. In addition, there was no indication that loss of the normal function of the tibialis posterior muscle resulted in change in foot alignment 2 years after surgery.

LEVEL OF EVIDENCE

Level III, retrospective comparative series.

Posterior tibial tendon transfer in the spastic brain-damaged adult does not lead to valgus flatfoot

BACKGROUND

We studied the possible development of valgus flat foot after transfer of the posterior tibial tendon to the lateral cuneiform, used for surgical restoration of dorsiflexion in brain-damaged adult patients with spastic equinovarus foot.

METHODS

Twenty hemiplegic patients were reviewed with a mean postoperative follow-up of 57.9 months. Weightbearing radiographs, static baropodometry analysis and functional evaluation were used to assess postoperatively outcomes.

RESULTS

On the operated side, weightbearing radiographs showed an absence of medial arch collapse and a symmetrical and physiological hindfoot valgus; static baropodometric analysis showed a reduced plantar contact surface with a pes cavus appearance. The surgical procedure yielded good functional results. Nineteen patients were satisfied with the outcome of their surgery.

CONCLUSIONS

Our findings support that transfer of the posterior tibial tendon does not lead to valgus flat foot in the spastic brain-damaged adult, and is still a current surgical alternative for management of spastic equinovarus foot.

Kinetics and kinematics after the Bridle procedure for treatment of traumatic foot drop

BACKGROUND

The Bridle procedure restores active ankle dorsiflexion through a tri-tendon anastomosis of the tibialis posterior, transferred to the dorsum of the foot, with the peroneus longus and tibialis anterior tendon. Inter-segmental foot motion after the Bridle procedure has not been measured. The purpose of this study is to report kinetic and kinematic variables during walking and heel rise in patients after the Bridle procedure.

METHODS

18 Bridle and 10 control participants were studied. Walking and heel rise kinetic and kinematic variables were collected and compared using an ANOVA.

FINDINGS

During walking the Bridle group, compared with controls, had reduced ankle power at push-off [2.3 (SD 0.7) W/kg, 3.4 (SD 0.6) W/kg, respectively, P<.01], less hallux extension during swing [-13 (SD 7)°, 15 (SD 6)°, respectively, P<.01] and slightly less ankle dorsiflexion during swing [6 (SD 4)°, 9 (SD 2)°, respectively, P=.03]. During heel rise the Bridle group had 4 (SD 6)° of forefoot on hindfoot dorsiflexion compared to 8 (SD 3)° of plantarflexion in the controls (P<.01).

INTERPRETATION

This study provides evidence that the Bridle procedure restores the majority of dorsiflexion motion during swing. However, plantarflexor function during push-off and hallux extension during swing were reduced during walking in the Bridle group. Abnormal mid-tarsal joint motion, forefoot on hindfoot dorsiflexion instead of plantarflexion, was identified in the Bridle group during the more challenging heel rise task. Intervention after the Bridle procedure must maximize ankle plantarflexor function and midfoot motion should be examined during challenging tasks.

Total and distributed plantar loading in subjects with stage II tibialis posterior tendon dysfunction during terminal stance

BACKGROUND

In subjects with stage II tibialis posterior tendon dysfunction (TPTD), the function of the tibialis posterior muscle is altered and may be associated with a change in total and distributed loading.

METHODS

Thirty subjects with a diagnosis of stage II TPTD and 15 matched control subjects volunteered to participate in a study to examine the total and distributed plantar loading under the foot during the terminal stance phase of gait. Plantar loading, measured as the subject walked barefoot, was assessed using instrumented flexible insoles. A secondary analysis was done to explore the contribution of flatfoot kinematics to plantar loading patterns.

RESULTS

Overall, there was reduced total plantar loading in subjects with stage II TPTD compared with controls. Accounting for differences in total loading, the presence of clinically measured weakness in subjects with TPTD was associated with reduced lateral forefoot loading. Medial longitudinal arch height was significantly correlated with loading patterns but explained only 21% of the variance in observed loading patterns.

CONCLUSION

Subjects with TPTD who are strong exhibited loading patterns similar to controls. Changes in total and distributed loading during terminal stance suggest there are altered ankle mechanics at push-off during the functional task of gait.

CLINICAL RELEVANCE

Strength, in the presence of TPTD, may be important to stabilize the midfoot during gait and might be important in rehabilitation protocols.

PTT functional recovery in early stage II PTTD after tendon balancing and calcaneal lengthening osteotomy

BACKGROUND

The decision to offer surgery for Stage II posterior tibial tendon deficiency (PTTD) is a difficult one since orthotic treatment has been documented to be a viable alternative to surgery at this stage. Taking this into consideration we limited our treatment to bony realignment by a lengthening calcaneus Evans osteotomy and tendon balancing. The goal of the study was to clinically evaluate PTT functional recovery with this procedure.

METHOD

The patient population included 17 feet in 13 patients. Inclusion was limited to early Stage II PTTD flatfeet with grossly intact but deficient PTT. Deficiency was assessed by the lack of hindfoot inversion during single heel rise test. The surgical procedure included an Evans calcaneal opening wedge osteotomy with triceps surae and peroneus brevis tendon lengthening. PTT function at follow up was evaluated by an independent examiner. Evaluation was performed at an average of 4 (range, 2 to 6.3) years.

RESULTS

One case presented postoperative subtalar pain that required subtalar fusion. Every foot could perform a single heel rise with 13 feet having active inversion of the hindfoot during elevation.

CONCLUSIONS

The results of this study provide evidence of PTT functional recovery without augmentation in early Stage II. It challenges our understanding of early Stage II PTTD as well as the surgical guidelines recommending PTT augmentation at this specific stage.

Peroneus longus transfer for drop foot in Hansen disease

Leprosy or Hansen's disease is a chronic infectious disease caused by the Mycobacterium leprae. Nerve injury is a central feature of the pathogenesis of leprosy that results in autonomic, sensory and motor neuropathy. One of the most common secondary disabilities caused by Hansen's disease is the drop foot and it is found in 2% to 5% of newly-diagnosed leprosy patients. Unlike the clinical picture of traumatic injury of the common peroneal nerve where both of its branches (the deep peroneal nerve and the superficial peroneal nerve) are involved, in leprosy there is the possibility of isolated involvement of the deep peroneal nerve branch, sparing the superficial peroneal branch. The article discusses the advantages of using the peroneus longus tendon transfer to the dorsum of the foot instead of the posterior tibial tendon for the correction of dropfoot in selected cases where the peroneals tendons are intact.

Tendon transfer options in managing the adult flexible flatfoot

Patients undergoing surgery for posterior tibial tendon dysfunction may require tendon transfer. The flexor digitorum longus is most commonly transferred, although the flexor hallucis longus and peroneus brevis have also been described in the literature. This article discusses the advantages and disadvantages of the different tendons, the surgical techniques used to perform them, and their results in the literature, concentrating principally on studies in which additional bone procedures were not performed. This article will also discuss the potential role for isolated soft tissue procedures in the treatment of stage 2 posterior tibial tendon dysfunction.

Tendon transfers for drop foot correction: long-term results including quality of life assessment, and dynamometric and pedobarographic measurements

BACKGROUND

Drop foot deformity is a common problem with severe restrictions in quality of life and impairment of daily activities. A technique of posterior tibial tendon transfer through the interosseus membrane and fixation to the anterior tibial and the long peroneal tendon "Bridle procedure" (stirrup-plasty) offers a physiological alternative to surgical correction.

METHODS

Data of 53 consecutive patients treated by stirrup-plasty were acquired from patient's charts; 31 were interviewed with standardized questionnaires; 20 were examined physically; 19 received pedobarography, and 8 underwent dynamometric muscle function tests. Follow-up time averaged 6.5 years.

RESULTS

The mean range of motion (ROM) in the ankle joint was 8° dorsiflexion and 15° plantar flexion. Most patients achieved plantigrade foot position and the majority developed gait without orthotic devices. As expected, maximum dorsiflexion torque averaged a third of the non-operated leg, according to reduced muscle diameter and strength of the transferred muscle. Pressure distribution of the sole during gait was not relevantly altered by the tendon transfer compared to the non-operated leg. Most patients were satisfied with the operative results and reported a significant increase in quality of life.

CONCLUSIONS

Fusion of the transposed posterior tibial, anterior tibial and the peroneus longus tendon prevents drop foot deformity sufficiently. The stirrup mechanism, in combination with tenodesis of the toe extensors, provides a balanced foot and avoids equinovarus and cavus deformity without immobilizing the ankle joint. Improvements in quality of life parameters justify the risk of the operative procedure for the patient.

Cadaveric flatfoot model: ligament attenuation and Achilles tendon overpull

Flatfoot deformity is characterized by loss of the medial longitudinal arch, forefoot abduction, hindfoot eversion, and often Achilles tendon contracture. Our objectives were to validate a cadaveric flatfoot model that involves selective ligament attenuation and to determine if Achilles tendon overpull is associated with increased pes planus severity. We measured the three-dimensional (3D) orientation of the bones of interest in the unloaded, loaded, and Achilles tendon overpull conditions. A flatfoot model was created by attenuating ligaments involved in the pes planus deformity followed by cyclic axial loading, and bone orientations were acquired in the three conditions. Significant differences seen between normal feet and flat feet were consistent with those seen with the pes planus deformity. The first metatarsal dorsiflexed and abducted relative to the talus. The navicular abducted relative to the talus. The calcaneus everted relative to the tibia. The talus plantar flexed and adducted. Achilles overpull resulted in first metatarsal-to-talus dorsiflexion and navicular-to-talus abduction. Thus, selective ligament attenuation followed by cyclic axial loading can create a cadaveric flatfoot model consistent with the in vivo deformity. Longitudinal arch depression, hindfoot eversion, talonavicular joint abduction, forefoot abduction, and talar plantar flexion were seen. Simulated Achilles tendon contracture increased the severity of the deformity, particularly in arch depression and forefoot abduction.

New tendon transfer for correction of drop-foot in common peroneal nerve palsy

Common peroneal nerve palsy has been reported to be the most frequent lower extremity palsy characterized by a supinated equinovarus foot deformity and foot drop. Dynamic tendon transposition represents the gold standard for surgical restoration of dorsiflexion of a permanently paralyzed foot. Between 1998 and 2005, we operated on a selected series of 16 patients with traumatic complete common peroneal nerve palsy. In all cases, we performed a double tendon transfer through the interosseous membrane. The posterior tibialis tendon was transferred to the tibialis anterior rerouted through a new insertion on the third cuneiform and the flexor digitorum longus was transferred to the extensor digitorum longus and extensor hallucis longus tendons. All 16 patients were reviewed at a minimum followup of 24 months (mean, 65 months; range, 24-114 months). The results were assessed using the Stanmore system questionnaire and were classified as excellent in eight, good in five, fair in two, and poor in one. Postoperative static and dynamic baropodometric evaluations also were performed. The proposed procedure, which provides an appropriate direction of pull with adequate length and fixation, is a reliable new method to restore balanced foot dorsiflexion correcting the foot and digit drop and producing a normal gait without the use of orthoses.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Adult-acquired flatfoot deformity following posterior tibialis to dorsum transfer: a case report

A previous study showed that flatfoot deformity does not develop after posterior tibialis to dorsum transfer in patients with peroneal nerve palsy. Their conclusion was that it is the unopposed pull of the peroneus brevis which leads to the flatfoot deformity in posterior tibial tendon dysfunction. This case report presents a patient who developed a flatfoot deformity after posterior tibialis to dorsum transfer despite nonfunctioning peroneal muscles.

Biomechanics and clinical analysis of the adult acquired flatfoot

The adult acquired flatfoot is a deformity that results from the loss of dynamic and static supportive structures of the medial longitudinal arch. The severity of the deformity is dependent upon the role of ligamentous disruption on the hindfoot that can be determined by careful clinical examination. Treatment of the adult flatfoot requires an understanding of the biomechanical effects of deforming forces, tendon dysfunction, ligament disruption, and joint sublaxation.

Giannini prosthesis for flatfoot

BACKGROUND

To determine the clinical and radiographic results of arthroereisis using the Giannini endo-orthotic implant for the treatment of pediatric flatfoot deformity, we retrospectively evaluated 37 patients (65 feet).

METHODS

Twenty-two boys and 15 girls were followed for an average of 26.5 months. Their overall average age was 9.4 (range 5 to 14) years. Pain, function, participation in sports activity, and the changes in radiographic measurements taken at 3, 6, and 12 months and then at 1-year intervals were evaluated.

RESULTS

Pain or discomfort decreased from 60% (22 patients) preoperatively to 6% (2 patients) postoperatively. The percentage of normal postoperative footprints was 59% (38 feet) with first-degree flatfoot present in 27 feet (41%). Sports activities were taken up by 19 patients (51%) after surgery. An 8-mm endo-orthotic implant was used in 43 (66%) feet and an Achilles tenotomy was done in 38 feet (59%). The radiographic angles with the greatest degree of correction when compared to preoperative angles were the talar-first metatarsal angle (99%) and the calcaneal-pitch (36%). After placement of the endo-orthotic implant, the talar angle influenced the rest of the radiographic measurements. There was no postoperative deterioration in any of the radiographic angles measured during the monitoring period. Complications occurred in 10.7% of the patients, with postoperative pain being the most frequently reported (6% of patients). There was no infection or local reaction to a foreign body. Removal of the endo-orthotic implant was not done on a routine basis.

CONCLUSION

This operative technique respects the anatomical structure of the foot and produces good clinical and radiographic results.

Palsy of the common peroneal nerve after traumatic dislocation of the knee

Injury to the common peroneal nerve was present in 14 of 55 patients (25%) with dislocation of the knee. All underwent ligament reconstruction. The most common presenting direction of the dislocation was anterior or anteromedial with associated disruption of both cruciate ligaments and the posterolateral structures of the knee. Palsy of the common peroneal nerve was present in 14 of 34 (41%) of these patients. Complete rupture of the nerve was seen in four patients and a lesion in continuity in ten. Three patients with lesions in continuity, but with less than 7 cm of the nerve involved, had complete recovery within six to 18 months. In the remaining seven with more extensive lesions, two regained no motor function, and one had only MRC grade-2 function. Four patients regained some weak dorsiflexion or eversion (MRC grade 3 or 4). Some sensory recovery occurred in all seven of these patients, but was incomplete. In summary, complete recovery occurred in three (21%) and partial recovery of useful motor function in four (29%). In the other seven (50%) no useful motor or sensory function returned.

Peroneus brevis is a more effective evertor than peroneus longus

A primary function of the peroneus longus and peroneus brevis is to provide the eversion moment necessary to balance the opposing inversion moments. Surgeons often deal with the loss of or need to sacrifice one of these tendons. This study compares the evertor mechanisms of the peroneus brevis and peroneus longus muscle. This is accomplished in a cadaver model in which the performance of each of the muscle tendons during early heel rise of gait is assessed utilizing the same tendon loads in each so that force is not a variable. Six fresh-frozen cadaver foot-ankle specimens were studied during a simulated early heel rise phase of the gait cycle. The study compared the effect of the peroneus brevis and peroneus longus by separately applying the same load to the each of the tendons. At the talonavicular joint, the peroneus brevis loaded condition externally rotated the navicular 2.1 degrees more than when the peroneus longus was loaded. At the subtalar joint, the peroneus brevis loaded condition resulted in 0.9 degrees more calcaneus valgus relative to the talus than was present during the peroneus longus loaded condition. The experimental data support the hypothesis that the peroneus brevis tendon mechanism is more effective than is the peroneus longus mechanism in rotating the navicular externally and the calcaneus into valgus. This has clinical implications for assisting surgeons in trying to preserve evertor function.

Recovery of the posterior tibial muscle after late reconstruction following tendon rupture

The purpose of this study was to determine the recovery potential of the posterior tibial muscle after late reconstruction following tendon rupture in stage II of posterior tibial tendon dysfunction. Fourteen patients (18 women, 6 men; mean age 59.8 years) were investigated 47 months (range, 24-76 months) after surgical reconstruction of a completely ruptured posterior tibial tendon (end-to-end anastomosis, side-to-side augmentation with the flexor digitorum longus tendon) in combination with a distal calcaneal osteotomy with a tricortical iliac crest bone graft for lengthening of the lateral column. At follow-up, clinical and radiological investigations were performed, including strength measurement and qualitative and quantitative MRI investigation. The overall clinical results were graded excellent in 12 patients, good in one, fair in one, and poor in none. The average ankle-hindfoot score (American Orthopaedic Foot and Ankle Society) improved from preoperatively 49.1 (range, 32-60) to 93.1 (range, 76-100) at follow-up. The functional result correlated with patient's satisfaction and sports activities (p <.05). All patients showed a significant strength of the posterior tibial muscle on the affected side, but it was smaller than on non-affected side (p <.05). The mean posterior tibial muscle strength was 75.1 N on affected and 104.9 N on nonaffected side, corresponding to a ratio of 0.73 between the two legs. The mean area of the posterior tibial muscle was 1.89 cm(2) on affected side, and 3.48 cm(2) on nonaffected side, corresponding to a ratio of 0.55 between the two legs. While fatty degeneration for the posterior tibial muscle was found in all patients, it was found to decrease with increasing strength of the posterior tibial muscle (p <.05) and muscular size (p <.05). On postoperative MRI, the posterior tibial tendon could be found to be intact in all patients. The recovery potential of the posterior tibial muscle was shown to be significant even after delayed repair of its ruptured tendon. A ruptured and/or diseased posterior tibial tendon should not be transected as it excludes any recovery possibilities of the posterior tibial muscle.

Issues relating to failure in the treatment of posterior tibial tendon dysfunction

As our understanding of the underlying cause of flat foot progression improves so will our understanding of how best to catalog and treat the instabilities that are seen. Determining the failure of one type of treatment will be difficult until we can better define the varied pathology and give the treatment methods sufficient time to prove or disprove their premise. If an underlying systemic disease, where either unreliable motor function or unstable ligament support is present, joint arthrodeses are the preferred method of treatment. It is important not to fuse in situ, but rather effect the complete realignment of the foot through the fused joints. At a minimum, I believe that the subtalar fusion is the most appropriate method for gaining a stable correction. Any more stability will warrant a triple arthrodesis. Treatment for the diseased tendon should also be addressed appropriately. Tendon reconstruction alone provides no assurance of weight-bearing deformity correction or lasting function for most patients who have isolated type 2 dysfunction and should be avoided as a stand-alone procedure. It still serves a vital purpose in restoring function to the foot, and, combined with other procedures, aids in the preservation of dynamic response to weight-bearing loads. The choice of adjunctive procedures should be based on the pathology present. Each of the treatment regimens that is discussed in this article has a place in the overall treatment of the clinical disease but none, by itself, seems to correct all of the presentations that are possible for this pathologic entity. The possible exception may be the use of a subtalar realignment and fusion, but this may be overkill in many mild to moderate deformities. Care should be taken in choosing the proper treatment based on the pathology that is presented by each patient.

Posterior tibial tendon force requirement in early heel rise after calcaneal osteotomies

Posterior tibial tendon insufficiency leads to decreased inversion strength. The purpose of this study was to measure the posterior tibial tendon force required to achieve early heel rise, defined as 7 degrees of calcaneal plantar flexion and 5 degrees of calcaneal inversion, in the intact foot and compare it to the requirements following medial displacement calcaneal osteotomy and following posterior distraction osteotomy. Thirteen cadaver specimens were loaded in a custom testing apparatus. The force required of the posterior tibial tendon to achieve early heel rise decreased from 399 +/- 50 N in the intact foot to 328 +/- 78 N (p < 0.001) after medial displacement osteotomy and 206 +/- 122 N (p < 0.001) after posterior distraction. Therefore, both the medial displacement and the posterior distraction osteotomies reduced the inversion demand at the posterior tibial tendon, with the distraction osteotomy being more effective in this reduction. Interestingly, these osteotomies also reduced the Achilles force required to achieve the heel rise position.

Tibialis posterior insufficiency occurring in a patient without peronei: a mechanical etiology

A patient presented with a painful flatfoot deformity, which developed after the onset of a drop-foot secondary to a herniated lumbar disk. On examination, the only functioning muscles were her gastrocnemius-soleus complex and her intrinsic toe flexors. Her affected foot had taken the classic deformity seen with tibialis posterior dysfunction--a valgus heel, midfoot collapse and an abducted forefoot. Peroneus brevis was not functioning and therefore could not be implicated as part of the etiology of this patient's acquired flatfoot deformity. The mechanism in which the ground reaction force produces the foot deformity in a tibialis posterior insufficient foot will be presented.

Outcome following addition of peroneus brevis tendon transfer to treatment of acquired posterior tibial tendon insufficiency

The flexor digitorum longus, the tendon most often used for transfer in posterior tibial tendon insufficiency, is one-half to one-third the size of the posterior tibial tendon. Occasionally it may be particularly small or may have been previously used for transfer. In these cases, the senior author has felt that the addition of a transfer of the Peroneus Brevis (PBr) tendon may be helpful in maintaining sufficient tendon and muscle mass to rebalance the foot. Thirteen patients who underwent this procedure were retrospectively identified and matched by age and length of follow-up to patients who underwent a more standard tendon transfer operation minus the addition of the PBr transfer. Pain and functional status were then assessed by the American Orthopaedic Foot and Ankle Society's ankle/hindfoot rating scale. Each patient was tested by an independent physical therapist to evaluate inversion and eversion strength. The mean duration of follow-up was 20.6 months (12 to 34 months). The average AOFAS score of the PBr group was 75.8 compared to 71.5 for the standard control group. There was no significant difference between the groups when inversion or eversion strengths were compared. Inversion strength and eversion strength was rated good or excellent (4 or 5) in 12 out of 13 of the PBr transfer group patients. No major complications were encountered in either group. Although it does not increase inversion strength, a PBr transfer can be used to augment a small FDL without causing significant eversion weakness. This can be useful when the FDL is particularly small or in revision surgery.

Treatment of stage 4 adult acquired flatfoot

Stage 4 PTT dysfunction is a rare anatomic condition in which fixed hindfoot valgus is associated with valgus tilting of the talus within the ankle mortise. Success with nonoperative management is the exception rather than the rule. The surgical options are a tibiotalocalcaneal fusion or a pantalar fusion; however, there are few results reported in the adult acquired flatfoot population. Valgus talar tilting after triple arthrodesis may be the challenge of the future.

Preliminary results comparing two methods of lateral column lengthening

Forty-five patients (49 feet) underwent lateral column lengthening as treatment for painful pes planus. Twenty-five patients (27 feet) were available for both radiographic and clinical evaluation at least one year postoperatively. Of these 25 patients, 10 feet underwent Evans opening wedge osteotomy with tricortical iliac crest bone graft; 17 feet underwent calcaneocuboid distraction arthrodesis utilizing iliac crest bone graft. In addition, both groups underwent debridement of the posterior tibial tendon combined with transfer of the flexor digitorum longus into the navicular for reinforcement. Radiographic results documented marked improvement in all parameters. There was more improvement in the calcaneocuboid fusion group than the osteotomy group, but the difference was not statistically significant. Postoperative AOFAS rating scores averaged 87.9 for the osteotomy group and 80.9 for the distraction arthrodesis group. The difference was not statistically significant. Twenty of 25 patients (83.5%) in both groups were very satisfied. Twenty-four of 25 patients (96%) stated that knowing the final result they would have the same surgery again. Complications were reported for 32 patients (34 feet). Both the Evans opening wedge calcaneal osteotomy and calcaneocuboid distraction arthrodesis offer significant improvement in the radiographic parameters and AOFAS clinical scores for patients with painful, flexible flatfoot deformity. However, the complication rate remains high with both methods, and the rate of nonunion and delayed union with the calcaneocuboid distraction arthrodesis method remains a significant problem with this technique.

Extrinsic muscle activity, foot motion and ankle joint moments during the stance phase of walking

This study examined stance phase foot kinematics, kinetics and electromyographic (EMG) activity of extrinsic muscles of 18 healthy males. Three-dimensional kinematic and kinetic data were obtained via video analysis of surface markers and a force plate. Ankle joint moments are described about orthogonal axes in a segmental coordinate system. Kinematic data comprise rearfoot and forefoot motion, described about axes of a joint coordinate system, and medial longitudinal arch height. Surface EMG was obtained for tibialis anterior, soleus, gastocnemius medialis and lateralis, peroneus longus and peroneus brevis and extensor digitorum longus. It was concluded that the demands on the controlling muscles are greatest prior to foot flat and after heel rise. Tibialis anterior restrained rearfoot plantarflexion from heel contact to 10% stance, and eversion between 10% stance and footflat. Activity in peroneus longus was consistent with its role in causing eversion after heel contact, then as a stabiliser of the forefoot after heel rise. Activity in peroneus brevis suggested a role in restraining lateral rotation of the leg over the foot, late in stance.

Tibialis posterior tendon dysfunction: a primary or secondary problem?

Seventeen patients with a mean follow-up of 64.4 months following a tibialis posterior tendon transfer to regain active foot dorsiflexion were clinically examined specifically for signs of tibialis posterior tendon dysfunction. The results show that 8 patients (47%) had Grade 4 or better power of eversion but none had a clinical flatfoot on the Harris-Beath footprints. Only 6% had forefoot abduction; 17% exhibited hindfoot valgus and 82% were able to perform the single-heel rise. Tibialis posterior tendon dysfunction therefore does not appear to be an inevitable sequel of tibialis posterior tendon transfer even in the presence of a functioning peroneal muscle. Other studies have noted that a pre-existent flatfoot was often present in patients with tibialis posterior tendon dysfunction. None of the patients in this study had pre-existent flatfoot. We suggest that a predisposition, in the form of a pre-existent tendency to flatfoot may also be a factor in the pathogenesis of tibialis posterior tendon dysfunction. This may explain the long-term failure of flexor digitorum longus and flexor hallucis longus tendon transfers in the treatment for tibialis posterior tendon dysfunction when the biomechanics of the foot has not been altered.