David B. Thordarson

Prospective Controlled Trial of STAR Total Ankle Replacement versus Ankle Fusion: Initial Results

Background: Mobile-bearing ankle replacements have become popular outside of the United States over the past two decades. The goal of the present study was to perform a prospective evaluation of the safety and efficacy of a mobile-bearing prosthesis to treat end stage ankle arthritis. We report the results of three separate cohorts of patients: a group of Scandanavian Total Ankle Replacement (STAR) patients and a control group of ankle fusion patients (the Pivotal Study Groups) and another group of STAR total ankle patients (Continued Access Group) whose surgery was performed following the completion of enrollment in the Pivotal Study. Materials and Methods: The Pivotal Study design was a non-inferiority study using ankle fusion as the control. A non-randomized multi-centered design with concurrent fusion controls was used. We report the initial perioperative findings up to 24 months following surgery. For an individual patient to be considered an overall success, all of the following criteria needed to be met: a) a 40-point improvement in total Buechel-Pappas ankle score, b) no device failures, revisions, or removals, c) radiographic success, and d) no major complications. In the Pivotal Study (9/00 to 12/01), 158 ankle replacement and 66 arthrodesis procedures were performed; in the Continued Access Study (4/02 to 10/06), 448 ankle replacements were performed, of which 416 were at minimum 24 months post-surgery at time of the database closure. Results: Major complications and need for secondary surgical intervention were more common in the Pivotal Study arthroplasty group than the Pivotal Study ankle fusion group. In the Continued Access Group, secondary procedures performed on these arthroplasty patients decreased by half when compared with the Pivotal Arthroplasty Group. When the Pivotal Groups were compared, treatment efficacy was higher for the ankle replacement group due to improvement in functional scores. Pain relief was equivalent between fusion and replacement patients. The hypothesis of non-inferiority of ankle replacement was met for overall patient success. Conclusion: By 24 months, ankles treated with STAR ankle replacement (in both the Pivotal and Continued Access Groups) had better function and equivalent pain relief as ankles treated with fusion. Level of Evidence: II, Prospective Controlled Comparative Surgical Trial

Operative vs. Nonoperative Treatment of Intra-Articular Fractures of the Calcaneus: A Prospective Randomized Trial:

Thirty patients with displaced, intra-articular calcaneus fractures were randomized to operative or nonoperative treatment. All patients had two or three major articular fragments of the posterior facet (Sanders type II or III). Nonoperative treatment included early mobilization and delayed weightbearing. Operative treatment involved open reduction and rigid internal fixation with a plate and screws through an extensile, L-shaped lateral approach followed by early mobilization and delayed weightbearing. Fifteen operative patients were evaluated at an average of 17 months follow-up and 11 nonoperative patients were seen at 14 months average follow-up. In the operative group, there were 7 excellent results, 5 good results, 2 fair results, and 1 poor result, and in the nonoperative group there was 1 excellent result, 3 good results, 1 fair result, and 6 poor results (difference significant at P < 0.01). A functional scoring system of 0–100 points was developed based upon the responses to an outcome assessment questionnaire. The average functional score for the operative group was far superior at 86.7, compared with 55.0 for the nonoperative group (P < 0.0001). Subtalar range of motion averaged 20° for the operative group and 17° for the nonoperative group with pain on extremes of motion of 25% of the operative patients compared with 100% of the nonoperative patients. This study is the first prospective, randomized trial to demonstrate the superior results of current operative treatment with early mobilization compared with nonoperative treatment.

The effect of fibular malreduction on contact pressures in an ankle fracture malunion model

Nine fresh-frozen cadaveric specimens were disarticulated through the knee, and the soft tissues, except for the interosseous ligaments and interosseous membrane, were removed to the level of the ankle. The subtalar joint was secured with screws in neutral position (approximately 5 degrees of valgus). Contact pressures in the tibiotalar joint were measured with use of low-grade pressure-sensitive film, which was placed through an anterior capsulotomy. For each measurement, 700 newtons of load was applied to the specimen for one minute. The film imprints were scanned, and the contact pressures were quantitated in nine equal quadrants over the talar dome. A fracture-displacement device was secured to the distal end of the fibula; the device allowed for individual or combined displacements consisting of shortening, lateral shift, and external rotation of the fibula. The ankle was maintained in neutral flexion. The ligamentous injury associated with a pronation-lateral rotation fracture of the ankle was simulated by dividing the deep fibers of the deltoid ligament, the anterior-inferior tibiofibular ligament, and the interosseous membrane to a point that was an average of fifty-three millimeters proximal to the ankle joint. Baseline contact area and contact pressure in the joint were determined, followed by measurements after two, four, and six millimeters of shortening of the fibula; after two, four, and six millimeters of lateral shift of the fibula; and after 5, 10, and 15 degrees of external rotation of the fibula. The three types of displacement were tested individually as well as in combination. The simulated deformities were found to cause a shift of the contact pressure to the mid-lateral and posterolateral quadrants of the talar dome, with pressures as high as 4.1 megapascals. A corresponding decrease in the contact pressures was noted in the medial quadrants of the talar dome. The highest pressures were recorded for maximum shortening of the fibula, the combination of maximum shortening and lateral shift, the combination of maximum shortening and external rotation, and the combination of maximum shortening, lateral shift, and external rotation. In general, increases in each displacement variable corresponded to increasing contact pressures. CLINICAL RELEVANCE: Previous biomechanical studies have demonstrated mixed results regarding the effect of lateral displacement of the talus on contact pressures in the ankle joint. We believe that we are the first to evaluate the individual and combined effects of shortening, lateral displacement, and malrotation of the fibula while load was applied through the tibial plateau—that is, while the tibia and fibula were loaded in a more physiological manner than accomplished previously. The findings of the present study confirm that substantial displacement of the fibula (two millimeters or more of shortening or lateral shift or 5 degrees or more of external rotation) increases the contact pressures in the ankle joint. Therefore, displacement of the fibula in these injuries should not be accepted.

Dynamic support of the human longitudinal arch: a biomechanical evaluation

This study was designed to evaluate the dynamic support provided to the human longitudinal arch by the leg muscles active in the stance phase of gait and by the plantar aponeurosis. Ten fresh adult cadaveric specimens were mounted in a materials testing machine. The tendons of the posterior tibialis, flexor digitorum longus, flexor hallucis longus, peroneus longus, peroneus brevis, and Achilles tendon were attached to force transducers. Plantar loads of 0, 350 and 700 N were applied, and the tendons were tensioned individually. The Achilles tendon was tensioned an amount equal to the plantar load; the posterior tibialis, flexor digitorum longus, flexor hallucis longus, peroneus longus, and peroneus brevis were tensioned a fractional amount (depending on the proportion of the cross-sectional area to the gastrocsoleus complex). The angular relationships between the first metatarsal, navicular, and talus were recorded using a 3-dimensional movement analysis system. An additional series of measurements was obtained by positioning the ankle plantarflexed 10° under a plantar load of 350 N. Dorsiflexing the toes with the ankle in a neutral position and loading the foot to 350 N and 700 N permitted an evaluation of the effect of the plantar aponeurosis. The plantar aponeurosis, via dorsiflexion of the toes, contributed the most significant arch support in the sagittal plane with a 3.6° increase between the first metatarsal and talus at 350 N and a 2.3° increase at 700 N. The posterior tibialis tendon consistently provided arch support at plantar loads of 350 N and 700 N. The peroneus longus consistently abducted the forefoot in the transverse plane at 350-N and 700-N load levels. The study provides further insight into the dynamic supporting and deforming forces of the longitudinal arch.

Ankle fusion in a high risk population: an assessment of nonunion risk factors

Between July 1992 and April 1996, 88 ankle fusions were performed at our institution. Sixty-seven of these had adequate follow-up for evaluation for union of the fusion, including adequate records and/or radiographs. The average age of patients was 43 years. There were 37 men and 24 women. The charts were reviewed to determine what level of trauma had resulted in posttraumatic arthritis (low energy, high energy, or open fracture). Alcohol use, drug abuse, diabetes, peripheral vascular disease, psychiatric history, smoking, or technical problems were also assessed. A chi-square analysis was used to evaluate the statistical significance. Nineteen of sixty-seven ankle fusions progressed to nonunion (28%). Eighty-five percent of the patients had posttraumatic arthritis. Among 17 patients with a history of open trauma, nine patients developed a nonunion (P < 0.03). A trend toward significance was noted for patients who were smokers, drank alcohol, had diabetes, had a psychiatric disorder, or used illegal drugs. Even with current techniques, this study demonstrates that a high risk population in a trauma center is at risk for nonunion after an ankle fusion caused by multiple risk factors, including a history of open trauma, tobacco use, alcohol use, illegal drug use, a history of psychiatric disorders, or diabetes.

Ankle Syndesmotic Injury

Abstract Ankle syndesmotic injury does not necessarily lead to ankle instability; however, the coexistence of deltoid ligament injury critically destabilizes the ankle joint. Syndesmotic injury may occur in isolation or may be associated with ankle fracture. In the absence of fracture, physical examination findings suggestive of injury include ankle tenderness over the anterior aspect of the syndesmosis and a positive squeeze or external rotation test. Radiographic findings usually include increased tibiofibular clear space decreased tibiofibular overlap, and increased medial clear space. However, syndesmotic injury may not be apparent radiographically; thus, routine stress testing is necessary for detecting syndesmotic instability. The goals of management are to restore and maintain the normal tibiofibular relationship to allow for healing of the ligamentous structures of the syndesmosis. Fixation of the syndesmosis is indicated when evidence of a diastasis is present. This may be detected preoperatively, in the absence of fracture, or intraoperatively, after rigid fixation of the medial malleolus and fibula fractures. Failure to diagnose and stabilize syndesmotic disruption adversely affects outcome.

Bioabsorbable Versus Stainless Steel Screw Fixation of the Syndesmosis in Pronation-Lateral Rotation Ankle Fractures: A Prospective Randomized Trial

Thirty-two patients who had pronation-lateral rotation (PLR) fractures occurring four centimeters or more proximal to the ankle joint or lower if the talus was displaced greater than one centimeter laterally were enrolled in this study. Seventeen patients were randomized to fibular plate fixation with a 4.5 ml polylactic acid (PLA) bioabsorbable syndesmotic screw, and fifteen patients randomized to fibular plate fixation with a 4.5 mm stainless steel syndesmotic screw. All thirty-two patients had uncomplicated healing of their fibular fracture without loss of reduction. There was neither evidence of osteolysis nor sterile effusion in the patients who were treated with the PLA screw. There were no wound complications in either group. No difference in range of motion or subjective complaints was noted in either group. Use of the PLA syndesmotic screw at short-term follow-up was well tolerated and avoided the need for subsequent screw removal.

Tibiotalocalcaneal arthrodesis using a dynamically locked retrograde intramedullary nail.

Background: Tibiotalocalcaneal arthrodesis is an important salvage method for patients with complex hindfoot problems, including Charcot arthropathy, osteonecrosis of the talus, combined arthritis of the ankle and subtalar joint, and failed total ankle arthroplasty. This study evaluated the results of a dynamic retrograde intramedullary nail for fixation with posterior to anterior distal interlocking screws placed through the calcaneus for tibiotalocalcaneal fusion. Methods: Thirty-three consecutive tibiotalocalcaneal fusions were done by a single surgeon (DBT) and were stabilized with a dynamic retrograde intramedullary nail. Time to fusion, impaction of the nail relative to the intramedullary canal, nail-tibial angle, and complications were noted. Average followup was 14 months. Results: Twenty-nine of 33 feet (88%) fused at an average of 3.7 months after surgery. Average impaction of the nail was 2.3 (0.5 to 5.0) mm. Cortical hypertrophy at the tip of the rod or at the proximal interlocking screw was noted in 13 of 27 patients. A trend toward a higher nonunion rate was noted in patients with an increased nail-tibial angle. Conclusion: Dynamic retrograde intramedullary nailing for fixation of the tibiotalocalcaneal fusions is a good method of stabilizing this complex fusion construct.

Complications After Treatment of Tibial Pilon Fractures: Prevention and Management Strategies

&NA; Complications after treatment of tibial pilon fractures can occur intraoperatively or in the early or late postoperative period. Perioperative complications include malreduction, inadequate fixation, and intra-articular penetration of hardware, all of which may be minimized by preoperative planning and meticulous operative technique. Wound complications can lead to deep infection, with potentially catastrophic consequences. The incidence of wound complications may be lessened by delaying surgery 5 to 14 days, until the posttraumatic swelling has subsided. Temporary fixation with a medial spanning external fixator is recommended if definitive internal fixation is delayed. Fracture blisters should be left undisturbed until the time of surgery. Incisions through bloodfilled blisters should be avoided whenever possible. Limited incisions to achieve reduction and fixation should be made directly over fracture sites, to minimize soft-tissue stripping. An indirect reduction technique involving the use ofligamentotaxis and low-profile small-fragment implants that minimize tension on the incision should be used. Late complications, such as stiffness and posttraumatic arthritis, correlate with the severity of the initial injury and the accuracy of reduction. Loss of ankle motion can be minimized by early range-of-motion exercise after stable fixation has been achieved. Posttraumatic ankle arthrosis should be initially treated with anti-inflammatory medication, activity modification, and walking aids. Symptomatic patients often require an ankle arthrodesis.

Correlation of hallux valgus surgical outcome with AOFAS forefoot score and radiological parameters.

Background: The purpose of the study was to evaluate the effect of three different types of hallux valgus surgeries on patient function using validated questionnaires and to correlate the results with radiographic and physical examinations. This study presents the 2-year followup data of a previous prospective outcome study. Methods: One hundred and ninety-six patients were enrolled in this study and completed a baseline AAOS Lower Limb Outcomes Data Collection Questionnaire. They completed the same form at 6, 12, and 24 months after having one of three types of hallux valgus surgeries (106 chevron osteotomies, 72 modified McBride procedures, and 18 modified Lapidus procedures). This questionnaire included the Short Form-36 Health Survey (SF-36) as well as questions relating to lower extremity function. Additionally, physicians were asked to complete preoperative and postoperative questionnaires on each patient that included radiographic and physical examination data and the type of surgery done. Completed outcome surveys and radiographic data were available on 196 patients, and physical examination scores were available to assign an AOFAS score in 111 patients at 24-month followup. A one-way comparison was done after stratifying the results for the type of surgery, preoperative hallux valgus angle and 1-2 intermetatarsal angle, postoperative hallux valgus angle and 1-2 intermetatarsal angle, and the change in the angles. Results: Four of the 10 SF-36 scores (physical function, role-physical, bodily pain, and role-emotional) for the combined data improved by more than five points. For the AAOS lower extremity function scores, physical health and pain (68.5 to 81.6), satisfaction with symptoms (1.8 to 3.6), global foot and ankle (77.6 to 93.4), and shoe comfort (29.0 to 58.7) scores all increased significantly. The AOFAS score increased from 52.6 to 85.5 (p < 0.001). Surprisingly, when comparing mild-to-moderate to severe deformities preoperatively and postoperatively using the absolute magnitude of the angular change in the hallux valgus or intermetatarsal angles, similar improvement was noted in AOFAS, SF-36, and AAOS lower extremity scores. The magnitude of preoperative deformity, postoperative residual deformity, and magnitude of correction also did not significantly change the amount of improvement in any of these scores. No significant differences were noted in the outcome scores among the three different surgeries. Conclusion: Patients who had hallux valgus surgery had significant improvements in four of their SF-36 scores, four of five of AAOS lower extremity scores, and AOFAS scores. The degree of deformity, amount of correction, or type of operation did not influence outcome.