The Effect of Tibiotalar Joint Line Level Alterations on Tibiotalar Range of Motion Following Total Ankle Arthroplasty.

BACKGROUND: The effect of tibiotalar joint line level (TTJL) on patient outcomes following total ankle arthroplasty (TAA) remains unclear. It was previously reported that patients with end-stage ankle arthritis have an elevated TTJL compared with nonarthritic ankles, and the TTJL post-TAA remains elevated compared with nonarthritic ankles. The objectives of this study were to (1) propose a reliable radiographic method to measure the TTJL absolute value and (2) determine the effect of TTJL alterations on tibiotalar range of motion (ROM) following TAA. METHODS: A retrospective review was performed on patients who underwent TAA between January 2018 and April 2021 with a minimum of 1-year postoperative follow-up and complete perioperative ROM radiographs. Radiographic TTJL and ROM measurements were performed by 2 observers. The proposed TTJL measuring technique computes 4 measurements: high, low, center of the talus (center), and center of the axis (axis). Reliability of measurements and correlation between TTJL measurements and ROM were assessed. RESULTS: A total of 33 patients were included. Postoperatively, 22 patients had a lowered TTJL compared to 11 patients with an elevated TTJL (2.2 ± 1.3 mm lowered vs 1.9 ± 1.2 mm elevated; P < .0001). Of the 4 TTJL measurements, 3 (low, center, axis) demonstrated a significant positive correlation between lowering the TTJL and improved tibiotalar dorsiflexion and 2 (low, axis) for total ROM (all P < .05). Plantarflexion was not significantly affected by TTJL alterations. Compared to patients with an elevated TTJL, patients with a lowered TTJL had improved tibiotalar dorsiflexion (8.8 vs 2.5 degrees; P = .0015) and total ROM (31.0 vs 22.9 degrees; P = .0191), respectively. The interrater reliability was nearly perfect (intraclass correlation r = 0.96-0.99). CONCLUSION: In this small series, we found that lowering the TTJL level may more closely reestablish the native TTJL and correlates with improved tibiotalar dorsiflexion and total ROM following TAA. LEVEL OF EVIDENCE: Level IV, case series.

The Hallux Metatarsophalangeal Capsule: An Anatomic Study With Respect to Percutaneous Hallux Valgus Correction.

BACKGROUND: Minimally invasive surgery for the treatment of hallux valgus deformities has become increasingly popular. Knowledge of the location of the hallux metatarsophalangeal (MTP) proximal capsular origin on the metatarsal neck is essential for surgeons in planning and executing extracapsular corrective osteotomies. A cadaveric study was undertaken to further study this anatomic relationship. METHODS: Ten nonpaired fresh-frozen frozen cadaveric specimens were used for this study. Careful dissection was performed, and the capsular origin of the hallux MTP joint was measured from the central portion of the metatarsal head in the medial, lateral, dorsal, plantarmedial, and plantarlateral dimensions. RESULTS: The ten specimens had a mean age of 77 years, with 5 female and 5 male. The mean distances from the central hallux metatarsal head to the MTP capsular origin were 15.2 mm dorsally, 8.4 mm medially, 9.6 mm laterally, 19.3 mm plantarmedially, and 21.0 mm plantarlaterally. CONCLUSION: The MTP capsular origin at the hallux metatarsal varies at different anatomic positions. Knowledge of this capsular anatomy is critical for orthopaedic surgeons when planning and performing minimally invasive distal metatarsal osteotomies for the correction of hallux valgus. TYPE OF STUDY: Cadaveric Study.

Weightbearing CT Analysis of the Transverse Tarsal Joint During Eversion and Inversion.

BACKGROUND: Understanding of the movement and function of the transverse tarsal joint (TTJt) continues to evolve. Most studies have been done in cadavers or under nonphysiologic conditions. Weightbearing computed tomographic (WBCT) scans may provide more accurate information about the position of the TTJt when the hindfoot is in valgus or varus. METHODS: Five volunteers underwent bilateral weightbearing CT scans while standing on a platform that positioned both hindfeet in 20 degrees of valgus and 20 degrees of varus. Each bone of the foot was segmented, and the joint surfaces of the talus, calcaneus, cuboid, and navicular were identified. The principal axes for each joint surface were determined and used to calculate the angles and distances between the bones with the foot in valgus or varus. RESULTS: In the coronal plane, the angle between the talus and calcaneus rotated 17.1 degrees as the hindfoot moved from valgus to varus. The distance between the centers of the talus and calcaneus decreased 7.1 mm. The cuboid translated 3.9 mm medially relative to the calcaneus. There was no change in angle or distance between the cuboid and navicular. The navicular rotated 25.4 degrees into varus relative to the talus. CONCLUSION: The TTJt locking mechanism was previously thought to occur from the talonavicular and calcaneocuboid joint axes moving from parallel to divergent as the hindfoot inverts. The current data show a more complex interaction between the four bones that comprise the TTJt and suggests that the locking mechanism may occur because of tightening of the ligaments and joint capsules. CLINICAL RELEVANCE: This study uses weight bearing CT scans of healthy, asymptomatic volunteers standing on valgus and varus platforms to characterize the normal motion of the transverse tarsal joint of the foot. A better understanding of how the transverse tarsal joint functions may assist clinicians in both the conservative and surgical management of hindfoot pathology.

Effect of Achilles Tendon Lengthening and Gastrocnemius Recession on Radiographic Tibiotalar Motion Following Total Ankle Replacement.

BACKGROUND: Surgeons frequently add an Achilles tendon lengthening or gastrocnemius recession to increase dorsiflexion following total ankle replacement. Previous studies have looked at the effects of these procedures on total tibiopedal motion. However, tibiopedal motion includes motion of the midfoot and hindfoot as well as the ankle replacement. The current study examined the effects of Achilles tendon lengthening and gastrocnemius recession on radiographic tibiotalar motion at the level of the prosthesis only. METHODS: Fifty-four patients with an average of 25 months follow-up after total ankle replacement were divided into 3 groups: (1) patients who underwent Achilles tendon lengthening, (2) patients who had a gastrocnemius recession, (3) patients with no lengthening procedure. Tibiotalar range of motion was measured on lateral dorsiflexion-plantarflexion radiographs using reference lines on the surface of the implants. RESULTS: Both Achilles tendon lengthening and gastrocnemius recession significantly increased tibiotalar dorsiflexion when compared to the group without lengthening. However, the total tibiotalar range of motion among the 3 groups was the same. Interestingly, the Achilles tendon lengthening group lost 11.7 degrees of plantarflexion compared to the group without lengthening, which was significant. CONCLUSION: Both Achilles tendon lengthening and gastrocnemius recession increased radiographic tibiotalar dorsiflexion following arthroplasty. Achilles tendon lengthening had the unexpected effect of significantly decreasing plantarflexion. Gastrocnemius recession may be a better choice when faced with a tight ankle replacement because it increases dorsiflexion without a compensatory loss of plantarflexion. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Painful Accessory Navicular and Spring Ligament Injuries in Athletes.

Painful accessory navicular and spring ligament injuries in athletes are different entities from more common posterior tibialis tendon problems seen in older individuals. These injuries typically affect running and jumping athletes, causing medial arch pain and in severe cases a pes planus deformity. Diagnosis requires a detailed physical examination, standing radiographs, and MRI. Initial treatment focuses on rest, immobilization, and restriction from sports. Orthotic insoles may alleviate minor pain, but many patients need surgery to expedite recovery and return to sports. The authors review their approach to these injuries and provide surgical tips along with expected rehabilitation to provide optimal outcomes.

Assessment of Bony Subfibular Impingement in Flatfoot Patients Using Weight-Bearing CT Scans.

BACKGROUND:: Lateral hindfoot pain in patients with flatfoot deformity is frequently attributed to subfibular impingement. It remains unclear whether this is primarily due to bony or soft-tissue impingement. No studies have used weight-bearing CT scans to evaluate subfibular impingement. METHODS:: Patients with posterior tibial tendonitis were retrospectively searched and reviewed. Subjects had documented flatfoot deformity, posterior tibial tenderness, weight-bearing plain radiographs, and a weight-bearing CT scan. CT scans were evaluated for calcaneofibular impingement on the coronal view and talocalcaneal impingement on the sagittal view. The distance between these structures was measured, along with the sinus tarsi volume. In the second part of this study, 6 normal volunteers underwent weight-bearing CT scans on a platform that held both feet in 20 degrees of varus, followed by 20 degrees of valgus. The same measurements were performed. RESULTS:: Thirty-five percent of flatfoot patients with posterior tibial tendonitis had bony impingement between the fibula and calcaneus on the coronal view. Thirty-eight percent had bony impingement between the talus and calcaneus on the sagittal view. Subjects with bony impingement based on CT scan had significantly higher talonavicular abduction angles on plain radiographs than those without impingement. Sinus tarsi volume decreased by more than half when the subtalar joint moved from varus to valgus in normal controls. CONCLUSION:: Bony subfibular impingement in patients with flatfeet was less common than previously reported. Accurate diagnosis of bony impingement may be useful for surgical decision-making. LEVEL OF EVIDENCE:: Level III, retrospective comparative study.

Measuring Visualized Tendon Length in Peroneal Tendoscopy.

BACKGROUND: Despite multiple studies outlining peroneal tendoscopy, no study exists to evaluate how effective tendoscopy is at visualizing the peroneal tendons without missing a lesion. We sought to measure the length of the peroneal tendons that could be visualized using tendoscopy. METHODS: Ten fresh cadaveric specimens were evaluated using standard peroneal tendoscopy techniques. Peroneus longus and brevis tendons were pierced percutaneously with Kirschner wires at the edge of what could be seen through the camera. The tendon sheaths were then dissected and the distances from anatomic landmarks were directly measured. During zone 3 peroneus longus tendoscopy, a more distal portal site was created for the final 5 specimens. RESULTS: The peroneus brevis could be visualized through the entirety of zone 1 and up to an average of 19.5 mm (95% confidence interval, 16.5-22.5) from its insertion onto the base of the fifth metatarsal in zone 2. Peroneus longus could be visualized through the entirety of zones 1 and 2 and up to an average of 9.7 mm from its insertion onto the base of the first metatarsal in zone 3. This distance was decreased significantly with a more distal portal. The muscle belly of peroneus brevis terminated an average of 1.8 mm (-3.7 to 7.3) above the tip of the lateral malleolus. CONCLUSIONS: Despite limitations, these results suggest that the vast majority of the length of the peroneal tendons can be seen during routine peroneal tendoscopy. A more distal skin portal site may improve visualization of zone 3 of peroneus longus. CLINICAL RELEVANCE: This study confirms the ability of peroneal tendoscopy to see the entire tendon length with appropriate portal placement.

Measuring Visualized Joint Surface in Hallux Metatarsophalangeal Arthroscopy.

BACKGROUND: Arthroscopy has been increasingly used to evaluate small joints in the foot and ankle. In the hallux metatarsophalangeal (MTP) joint, little data exist evaluating the efficacy of arthroscopy to visualize the articular surface. The goal of this cadaveric study was to determine how much articular surface of the MTP joint could be visualized during joint arthroscopy. METHODS: Ten fresh cadaveric foot specimens were evaluated using standard arthroscopy techniques. The edges of the visualized joint surface were marked with curettes and Kirschner wires; the joints were then surgically exposed and imaged. The visualized surface area was measured using ImageJ® software. RESULTS: On the distal 2-dimensional projection of the joint surface, an average 57.5% (range, 49.6%-65.3%) of the metatarsal head and 100% (range, 100%-100%) of the proximal phalanx base were visualized. From a lateral view of the metatarsal head, an average 72 degrees (range, 65-80 degrees) was visualized out of an average total articular arc of 199 degrees (range, 192-206 degrees), for an average 36.5% (range, 32.2%-40.8%) of the articular arc. CONCLUSION: Complete visualization of the proximal phalanx base was obtained. Incomplete metatarsal head visualization was obtained, but this is limited by technique limitations that may not reflect clinical practice. CLINICAL RELEVANCE: This information helps to validate the utility of arthrosocpy at the hallux metatarsophalangeal joint.

Outcome of Lateral Transfer of the FHL or FDL for Concomitant Peroneal Tendon Tears.

BACKGROUND: Concomitant tears of the peroneus longus and brevis tendons are rare injuries, with literature limited to case reports and small patient series. Only 1 recent study directly compared the results of single-stage lateral deep flexor transfer, and no previous series objectively evaluated power and balance following transfer. The purpose of this study was to evaluate clinical outcomes, patient satisfaction, and objective power and balance data following single-stage flexor hallucis longus (FHL) and flexor digitorum longus (FDL) tendon transfers for treatment of concomitant peroneus longus and brevis tears. METHODS: Over an 8-year period (2005-2012), 9 patients underwent lateral transfer of the FHL or FDL tendon for treatment of concomitant peroneus longus and brevis tears. All but 1 patient underwent additional procedures to address hindfoot malalignment or other contributing deformity at the time of surgery. Mean age was 56.9 years, and average body mass index was 27.9. Lateral transfer of the FHL was performed in 5 patients, and FDL transfer performed in 4 with mean follow-up 35.7 months (range: 11-94). Eight of 9 patients completed SF-12 and Foot Function Index (FFI) scores, and 7 returned for range of motion (ROM) and manual strength testing of the involved and normal extremities. These 7 patients also completed force plate balance tests, in addition to peak force and power testing on a PrimusRS machine with a certified physical therapist. RESULTS: All patients were satisfied with the results of the procedure. Mean SF-12 physical and mental scores were 32 and 55, respectively; mean FFI total score was 56.7. No postoperative infections were noted. Two patients continued to utilize orthotics or braces, and 2 patients reported occasional pain with weightbearing activity. Three patients noted mild paresthesias in the distribution of the sural nerve and 2 demonstrated tibial neuritis. All patients demonstrated 4/5 eversion strength in the involved extremity. Average loss of inversion and eversion ROM were 24.7% and 27.2% of normal, respectively. Mean postoperative eversion peak force and power were decreased greater than 55% relative to the normal extremity. Patients demonstrated nearly 50% increases in both center-of-pressure tracing length and velocity during balance testing. There were no statistically significant differences between the FHL and FDL transfer groups with regards to clinical examination or objective power and balance tests. CONCLUSION: The FHL and FDL tendons were both successful options for lateral transfer in cases of concomitant peroneus longus and brevis tears. Objective measurements of strength and balance demonstrated significant deficits in the operative extremity, even years following the procedure. These differences, however, did not appear to alter or inhibit patient activity levels or high satisfaction rates with the procedure. Although anatomic studies have demonstrated benefits of FHL transfer over the FDL tendon, further studies with increased patient numbers are needed to determine if these differences are clinically significant. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Anatomic comparison of lateral transfer of the long flexors for concomitant peroneal tears.

BACKGROUND: Lateral transfers of the flexor hallucis longus (FHL) or flexor digitorum longus (FDL) tendons have been described for treatment of concomitant, irreparable peroneal tears. This study evaluated the anatomic benefits and constraints of lateral FHL and FDL tendon transfers with regard to available tendon length, diameter, and proximity to the posterior neurovascular bundle. METHODS: In 9 cadaveric specimens, the FHL and FDL tendons were transected through a medial approach distal to the knot of Henry. Each tendon was transferred into a lateral incision, passing the FDL tendon both posterior and anterior to the tibial neurovascular bundle. The tendons were individually secured to the base of the fifth metatarsal with the foot in maximal eversion and dorsiflexion. The length of donor tendon available for fixation at the fifth metatarsal was measured. After the FDL tendon transfer was secured, the posterior neurovascular bundle was examined for signs of compression. RESULTS: Average FHL tendon diameter measured 5.1 mm; the FDL measured 4.5 mm. After passage through a bone tunnel, an additional 4.9 cm of FHL tendon remained to suture to itself; only 0.5 cm remained for the posterior and anterior FDL transfers. Transfer of the FHL did not increase muscle bulk within the retrofibular groove. Every FDL transfer posterior to the neurovascular bundle produced obvious visual compression of the tibial nerve with plantar flexion and inversion of the foot. CONCLUSION: Use of the FHL tendon for lateral transfer consistently provided sufficient length of tendon for multiple fixation options and a stronger muscle for transfer. Fixation options for the FDL were limited due to its shorter length. Lateral transfer of the FDL tendon posterior to the neurovascular bundle caused visible compression on the tibial nerve with ankle and hindfoot range of motion. CLINICAL RELEVANCE: This anatomic study confirmed several advantages for the use of the FHL tendon transfer in cases of concomitant peroneal tears.

Tibiotalocalcaneal arthrodesis with bulk femoral head allograft for salvage of large defects in the ankle.

BACKGROUND: Tibiotalocalcaneal arthrodesis in patients with large segmental bony defects presents a substantial challenge to successful reconstruction. These defects typically occur following failed total ankle replacement, avascular necrosis of the talus, trauma, osteomyelitis, Charcot, or failed reconstructive surgery. This study examined the outcomes of tibiotalocalcaneal (TTC) arthrodesis using bulk femoral head allograft to fill this defect. METHODS: Thirty-two patients underwent TTC arthrodesis with bulk femoral head allograft. Patients who demonstrated radiographic union were contacted for SF-12 clinical scoring and repeat radiographs. Patients with asymptomatic nonunions were also contacted for SF-12 scoring alone. Preoperative, intraoperative, and postoperative factors were analyzed to determine positive predictors for successful fusion. RESULTS: Sixteen patients healed their fusion (50% fusion rate). Diabetes mellitus was found to be the only predictive factor of outcome; all 9 patients with diabetes developed a nonunion. In this series, 19% of the patients went on to require a below-knee amputation. CONCLUSIONS: Although the radiographic fusion rate was low, when the 7 patients who had an asymptomatic nonunion were combined with the radiographic union group, the overall rate of functional limb salvage rose to 71%. TTC arthrodesis using femoral head allograft should be considered a salvage procedure that is technically difficult and carries a high risk for complications. Patients with diabetes mellitus are at an especially high risk for nonunion. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Posterior tibial tendon tear after 4-cortex syndesmotic screw fixation: a case report and literature review.

We describe a previously unreported problem of a patient who underwent errant 4-cortex syndesmotic screw fixation with resultant posterior tibial tendon tear necessitating removal of hardware and repair of a tendon tear.

Effect of a steel toe cap on forefoot injury pattern in a cadaveric model.

BACKGROUND: Crush injuries to the foot are a common workplace injury and a significant source of morbidity, disability and lost wages. Many regulatory bodies including the Occupational Safety and Health Administration (OSHA) recommend the use of safety shoes in certain occupations to help protect against these occupational hazards. However there remains controversy and paucity of published data regarding the protection afforded by a steel toe cap in regards to clinical injury pattern. This study looks to investigates the protective influence of a steel toe cap on crush injuries of the forefoot. MATERIALS AND METHODS: Five non-osteoporotic paired cadaver lower extremities were appropriately fitted to a standard work boot. One foot of each pair was fitted into a steel toe capped boot (designated ``ST'' group) while the other foot was fitted into an identical version of the work boot but without the protective steel toe cap (designated ``NST'' group). Each foot was crushed using a custom designed rig with a load of 150 lb dropped from a calibrated height of 3 feet to the forefoot. X-rays were obtained to assess fracture location & comminution and stress fluoroscopy was used to assess for any ligamentous Lisfranc injury. RESULTS: The NST group averaged 8.2 fractured bones per foot while the ST group averaged 3.6 fractured bones per foot (p = 0.001). The NST group demonstrated significantly more metatarsal fractures (3.2 fractures/foot) versus the ST group (one fracture/foot) (p = 0.020). The NST group demonstrated significantly more proximal phalanx fractures (4.2 fractures/foot) compared to the ST group (2.6 fractures/foot) (p = 0.035). Middle and distal phalanx fractures were not significantly different between the two groups. A higher percentage of the bones fractured were deemed comminuted in the NST group (53.6%) versus the ST group (38.8%) although this did not reach statistical significance. CONCLUSION: This study demonstrated that the steel toe affords protective advantages in crush injuries to the foot in limiting the number and severity of metatarsal and proximal phalanx fractures. However the steel toe does not fully protect the forefoot from injury. CLINICAL RELEVANCE: Crush injuries to the foot are a common workplace injury. Strict adherence to workplace safety standards may limit the severity of crush injuries to the foot and additional safety measures such as metatarsal guards should be considered when appropriate.

Inadvertent screw stripping during ankle fracture fixation in elderly bone.

Poor screw purchase because of osteoporosis presents difficulties in ankle fracture fixation. The aim of our study was to determine if cortical thickness, unicortical versus bicortical purchase, and bone mineral density are predictors of inadvertent screw stripping and overtightening. Ten paired cadaver ankles (average donor age, 81.7 years; range, 50-97 years) were used for the study. Computed tomography scanning with phantoms of known density was used to determine the bone density along the distal fibula. A standard small-fragment, 7-hole, one-third tubular plate was applied to the lateral surface of the fibula, with 3 proximal bicortical cortical screws and 2 distal unicortical cancellous screws. A posterior plate, in which all 5 screws were cortical and achieved bicortical purchase, was subsequently applied to the same bones and positioned so that the screw holes did not overlap. A torque sensor was used to measure the torque of each screw during insertion (Ti) and then stripping (Ts). The effect of bone density, screw location, cortical thickness, and unicortical versus bicortical purchase on Ti and Ts was checked for significance (P < .05) using a general linearized latent and mixed model. We found that 9% of the screws were inadvertently stripped and 12% were overtightened. Despite 21% of the screws being stripped or being at risk for stripping, we found no significant predictors to warn of impending screw stripping. Additional work is needed to identify clinically useful predictors of screw stripping.

Posterior calf injury.

Acute injuries of the Achilles tendon are common among athletes and non-athletes alike. Injuries of other posterior calf muscles are far less common but should be considered in the differential, to ensure proper diagnosis and treatment of patients with calf injuries. This article focuses on these calf injuries, including injuries of the gastrocnemius, plantaris, soleus, and flexor hallucis longus, which may occasionally be mistaken for Achilles tendon disorders.

Prediction of three-dimensional contact stress and ligament tension in the ankle during stance determined from computational modeling.

BACKGROUND: Our goal was to quantify and visualize the three-dimensional loading relationship between the ligaments and articular surfaces of the ankle to identify and determine the stabilizing roles of these anatomical structures during the stance phase of gait. MATERIALS AND METHODS: We applied discrete element analysis to computationally model the three-dimensional contact characteristics and ligament loading of the ankle joint. Physiologic loads approximating those at five positions in the stance phase of a normal walk cycle were applied. We analyzed joint contact pressures and periankle ligament tension concurrently. RESULTS: Most ankle joint loading during the stance phase occurred across the articular surfaces of the joint, and the amount of ligament tension was small. The tibiotalar articulation showed full congruency throughout most of the stance phase, with peak pressure developing anteriorly toward the toe-off frame. Of the periankle ligaments, the deep deltoid ligament transferred the most force during the stance phase (57.2%); the superficial deltoid ligament transferred the second-most force (26.1%). The anterior talofibular ligament transferred force between the talus and fibula continuously, whereas the calcaneofibular ligament did not carry force during gait. The distal tibiofibular ligaments and the interosseous membrane were loaded throughout the stance phase. CONCLUSION: Force transmission through the ankle joint during the stance phase is predominantly through the articular surfaces, and the periankle ligaments do not play a major stabilizing role in constraining ankle motion. The medial ligaments have a more important role than do the lateral ligaments in stabilizing the ankle joint. CLINICAL RELEVANCE: In addition to ligament insufficiency, other factors, such as varus tilt of the tibial plafond, may be important in the development of recurrent instability. Continuous loading of syndesmosis ligaments provides a theoretical basis for evidence of syndesmosis screw breakage or loosening. The analysis method has potential applications for clarifying ankle joint function and providing a basis for comparison between normal and abnormal joint conditions.