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.

Reproducibility of computed tomography to evaluate ankle and hindfoot fusions.

BACKGROUND: Although plain radiographs have been historically used to evaluate the status of arthrodesis in the foot and ankle, computed tomography (CT) has gained popularity for evaluation of fusion status. The degree of fusion identified on CT scan has been correlated with functional outcome, with an arthrodesis area of 25-50% necessary for clinical success. In the clinical setting, orthopaedic surgeons often evaluate CT scans independently. The purpose of this study was to evaluate the interrater reliability of CT scans to assess the status of hindfoot or ankle fusions among orthopaedic foot and ankle surgeons. METHODS: Forty-one CT scans were identified retrospectively from the tertiary referral practices of 4 fellowship-trained orthopaedic foot and ankle surgeons. Inclusion criteria were patients with ankle, subtalar, or tibiotalocalcaneal fusions. Fusions with bulk allograft were excluded. All CT scans were completed at the investigating institution. The primary author (RAC) reviewed all CT scans to ensure the adequacy and completeness of the films. Images were blinded of any patient identifiers. All 4 surgeons individually reviewed the blinded scans and determined whether the arthrodesis site was greater than or less than 50% fused. Interrater reliability was completed via kappa analysis. RESULTS: Based on kappa analysis, there was high interrater reliability in the assessment of subtalar arthrodesis. This was not statistically significant for the evaluation of ankle arthrodesis. CONCLUSION: The CT scan has become instrumental in determining the adequacy of arthrodesis in the foot and ankle. The present study demonstrates the reliability of orthopaedic surgeons to ascertain the status of subtalar arthrodesis via CT scan. LEVEL OF EVIDENCE: Level IV, 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.

Relative strengths of the calf muscles based on MRI volume measurements.

BACKGROUND: In 1985, Silver et al. published a cadaver study which determined the relative order of strength of the muscles in the calf. Muscle strength, which is proportional to volume, was obtained by dissecting out the individual muscles, weighing them, and then multiplying by the specific gravity. No similar studies have been performed using {\it in vivo} measurements of muscle volume. METHODS: Ten normal subjects underwent 3-Tesla MRI's of both lower extremities using non-fat-saturated T2 SPACE sequences. The volume for each muscle was determined by tracing the muscle contour on sequential axial images and then interpolating the volume using imaging software. RESULTS: The results from this study differ from Silver's original article. The lateral head of the gastrocnemius was found to be stronger than the tibialis anterior muscle. The FHL and EDL muscles were both stronger than the peroneus longus. There was no significant difference in strength between the peroneus longus and brevis muscles. CONCLUSION: This revised order of muscle strengths in the calf based on in vivo MRI findings may assist surgeons in determining the optimal tendons to transfer in order to address muscle weakness and deformity.

Driving brake reaction time following right ankle arthrodesis.

BACKGROUND: The purpose of this study was to compare the brake reaction time of patients with successful right ankle fusion to normal volunteers without an ankle fusion. METHODS: Ten patients who underwent successful right ankle arthrodesis were evaluated using a driving simulator as well as an in-shoe pedobarographic measuring system. Brake reaction time, braking force, peak pressure, contact area, and the center of force between the foot and the brake pedal were recorded. SF-12 scores were obtained from all study patients. A control group of ten age-matched individuals without ankle fusion was included for comparison. RESULTS: Mean brake reaction time for the ankle fusion group (0.42+/-0.14 seconds) was significantly slower than for the control group (0.33+/-0.06 seconds) (p=0.03). The center of force was consistently isolated to the forefoot in the ankle fusion group compared to controls who distributed the center of force over both the forefoot and midfoot. There was no significant difference between the ankle fusion and control groups with respect to braking force, peak pressure, or contact area. CONCLUSION: The mean brake reaction time following successful right ankle arthrodesis was significantly slower than that of normal controls. However, the fusion group time was still below the threshold for what is defined as a safe brake reaction time by the United States Federal Highway Administration.

Minimally invasive deltoid ligament reconstruction for stage IV flatfoot deformity.

BACKGROUND: Stage IV is the most advanced form of acquired adult flatfoot deformity (AAFD). It is present when valgus tibiotalar angulation occurs with foot deformities associated with AAFD. Tibiotalocalcaneal or pantalar fusion has been the gold standard for treatment of Stage IV AAFD. However, in some of these patients the tibiotalar deformity is correctable. We sought to determine whether minimally invasive deltoid ligament reconstruction in conjunction with triple arthrodesis (MIDLR/Triple) allows tibiotalar joint sparing surgical therapy in Stage IV-A AAFD patients. MATERIALS AND METHODS: Patients diagnosed with Stage IV-A AAFD were given the option of undergoing ankle joint sparing surgery with the MIDLR/Triple technique. Those that chose this option were followed longitudinally. Eight patients underwent the ankle joint sparing procedure. Average followup was 36 months. Radiographic and functional outcome measures were obtained. Success was defined as maintenance of 3 degrees or less of valgus tibiotalar angulation and greater than 2 mm of lateral joint space remaining at final followup. RESULTS: At final followup, five were judged to have a successful outcome. In those, tibiotalar valgus angulation was reduced from 6.4±2.9 degrees to 2.0±2.0 degrees, lateral ankle joint space was maintained at preoperative levels and SF-12 functional scores were equal to age matched normative scores. The only parameter found to be predictive of successful outcome was the magnitude of preoperative tibiotalar tilt. CONCLUSIONS: MIDLR/triple is a new treatment option that requires significant care in patient selection and surgical execution. It is a choice that allows for preservation of ankle motion in patients diagnosed with Stage IV-A AAFD who have less than 10 degrees of valgus tibiotalar tilt on preoperative standing ankle radiographs.

Comparison of initial compression of the medial, lateral, and posterior screws in an ankle fusion construct.

BACKGROUND: One of the requirements for successful ankle arthrodesis is adequate compression by the fixation across the fusion surfaces. A common screw construct for ankle fusion is three crossed screws from proximal-to-distal. Because the screws are inserted nearly orthogonal to each other, it is possible minimal additional compression is obtainable once the first screw is inserted. The aim of this study was to determine which of the three screws gave the greatest initial compression and theoretically should be inserted first. MATERIALS AND METHODS: Seventeen cadaver limbs were dissected to expose the anterior and posterior aspects of the tibiotalar joint. Three Fuji film templates were created for each ankle joint with a hole to accommodate a 7.0-mm cannulated screw. Each film was tested with a single medial, lateral, or posterior screw. The Fuji films were then analyzed for contact area, percent contact area, and pressure. RESULTS: There was no difference in the total contact area, percent contact area, or pressure generated between the three screws. The mean contact area for all screws was 11% of the joint surface. All three screws had greater contact area and percent contact area over the anterior half of the ankle joint. CONCLUSION: The medial, lateral, and posterior screws were equivalent with respect to contact area, percent contact area, and pressure generated across the tibiotalar joint. All three screws had greater contact area over the anterior half of the joint. Only 11% of the tibiotalar joint surface came in contact following the insertion of a single partially threaded screw. CLINICAL RELEVANCE: In a neutrally aligned ankle arthrodesis the order of screw insertion does not affect the amount of compression ultimately achieved at the fusion site.

Percutaneous screw configuration versus perimeter plating of calcaneus fractures: a cadaver study.

BACKGROUND: Percutaneous screw configuration has been used clinically to reduce the high rate of wound complications associated with the extensile approach of standard open reduction and internal plate fixation. The aim of this cadaveric biomechanical study was to compare the strength of the standard perimeter plating with that of the percutaneous screw configuration for a Sanders type-2B calcaneus fracture. MATERIALS AND METHODS: Ten pairs of fresh-frozen cadaveric lower limbs were prepared and osteotomized to create a Sanders type-2B fracture. Of each pair, one specimen underwent open reduction and internal fixation with standard perimeter plating; the other was stabilized with the percutaneous screw configuration. Each foot was compressed axially via the talar dome (1 mm/sec) until failure occurred. Differences in treatment groups were analyzed for significance (p < 0.05) using paired t-tests. RESULTS: Construct stiffness was 158 +/- 85 and 113 +/- 60 N/mm for the plate and percutaneous fixation, respectively (p = 0.18). Failure occurred at an average of 1156 +/- 513 and 1064 +/- 540 N for the plate and percutaneous construct, respectively (p = 0.65). CONCLUSION: The results suggest that open reduction and internal fixation with percutaneous screw configuration for Sanders type-2B calcaneus fractures provides a strength similar to that of perimeter plating. CLINICAL RELEVANCE: Percutaneous screw fixation of calcaneus fractures may provide fracture reduction similar to plate fixation.