Jonathan T. Deland

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

Motion of the Hindfoot after Simulated Arthrodesis

Arthrodesis of the subtalar joint, triple arthrodesis (involving the subtalar, talonavicular, and calcaneocuboid joints), double arthrodesis (involving the talonavicular and calcaneocuboid joints), arthrodesis of the talonavicular joint, and arthrodesis of the calcaneocuboid joint were simulated in a cadaver model, and the range of motion of each joint not involved in the simulated arthrodesis was measured with a three-dimensional magnetic space tracking system. The excursion of the posterior tibial tendon was also measured under all of these conditions. We found that any combination of simulated arthrodeses that included the talonavicular joint severely limited the motion of the remaining joints to about 2 degrees and limited the excursion of the posterior tibial tendon to 25 per cent of the preoperative value. Simulated arthrodesis of the calcaneocuboid joint had little effect on the range of motion of the subtalar joint, and it reduced the range of motion of the talonavicular joint to a mean of 67 per cent of the preoperative value; a mean of 73 per cent of the excursion of the posterior tibial tendon was retained. After simulated arthrodesis of the subtalar joint, a mean of 26 per cent of the motion of the talonavicular joint, 56 per cent of the motion of the calcaneocuboid joint, and 46 per cent of the excursion of the posterior tibial tendon was retained. The talonavicular joint is the key joint of the triple joint complex. The talonavicular joint had the greatest range of motion, and simulated arthrodesis of this joint essentially eliminated motion of the other joints of the complex. CLINICAL RELEVANCE: Arthrodesis of any of the joints of the so-called triple joint complex (the subtalar, talonavicular, and calcaneocuboid joints) limits the motion of the remaining, unfused joints. However, clinical estimates of these limitations are imprecise and motion of the individual joints cannot be specifically measured clinically. It is important to be able to measure the limitation of motion of each joint after arthrodesis of the other joints in order to understand the clinical implication of the arthrodesis. Also, it is necessary to ascertain the effect of limiting the motion of these joints on the excursion of the posterior tibial tendon in order to determine when it is appropriate to reconstruct the tendon concomitantly with these arthrodeses.

Adult-acquired Flatfoot Deformity

Abstract Originally known as posterior tibial tendon dysfunction or insufficiency, adult‐acquired flatfoot deformity encompasses a wide range of deformities. These deformities vary in location, severity, and rate of progression. Establishing a diagnosis as early as possible is one of the most important factors in treatment. Prompt early, aggressive nonsurgical management is important. A patient in whom such treatment fails should strongly consider surgical correction to avoid worsening of the deformity. In all four stages of deformity, the goal of surgery is to achieve proper alignment and maintain as much flexibility as possible in the foot and ankle complex. However, controversy remains as to how to manage flexible deformities, especially those that are severe.

Posterior Tibial Tendon Insufficiency: Which Ligaments are Involved?:

Background: The pathology manifested in posterior tibial tendon insufficiency (PTTI) is not limited to the posterior tibial tendon. The association of ligament failure with deformity has been discussed in numerous publications, but extensive documentation of the structures involved has not been performed. The purpose of this observational study was to identify the pattern of ligament involvement using standarized, high-resolution magnetic resonance imaging (MRI) in a series of 31 consecutive patients diagnosed with PTTI compared to an age matched control group without PTTI. Method: The structures evaluated by MRI were the posterior tibial tendon, superomedial and inferomedial components of the spring ligament complex, talocalcaneal interosseous ligament, long and short plantar ligaments, plantar fascia, deltoid ligament, plantar naviculocuneiform ligament, and tarsometatarsal ligaments. Structural derangement was graded on a five-part scale (0 to IV) with level 0 being normal and level IV indicating a tear of more than 50% of the cross-sectional area of the ligament. Standard flatfoot measurements taken from preoperative plain standing radiographs were correlated with the MRI grading system. Results: Statistically significant differences in frequency of pathology in the PTTI group and controls were found for the superomedial calcaneonavicular ligament (p < 0.0001), inferomedial calcaneonavicular ligament (p < 0.0001), interosseous ligament (p = 0.0009), anterior component of the superficial deltoid (p < 0.0001), plantar metatarsal ligaments (p = 0.0002) and plantar naviculocuneiform ligament (p = 0.0006). The ligaments with the most severe involvement were the spring ligament complex (superomedial and inferomedial calcaneonavicular ligaments) and the talocalcaneal interosseous ligament. Conclusion: Ligament involvement is extensive in PTTI, and the spring ligament complex is the most frequently affected. Because ligament pathology in PTTI is nearly as common as posterior tibial tendinopathy, treatment should seek to protect or prevent progressive failure of these ligaments.

Adult Acquired Flatfoot Deformity at the Talonavicular Joint: Reconstruction of the Spring Ligament in an in Vitro Model

The mobile unilateral flatfoot deformity of chronic posterior tibial tendon insufficiency has been difficult to correct by soft tissue procedures. The procedures can decrease pain, but they do not always correct the longitudinal arch or relieve all the symptoms. Using 10 fresh frozen cadaveric specimens and a rig for stimulation of weightbearing, the deformity associated with chronic posterior tibial tendon insufficiency was produced by multiple ligamentous release and documented by AP and lateral radiographs. Reconstruction of the spring ligament using a ligament bone autograft from the superficial deltoid ligament was then performed and tested under load. The mean correction was within 2.5° of normal (over or undercorrection) on both the AP and lateral radiographs with the specimens under load. Clinical Relevance. In posterior tibial tendon insufficiency, it may be possible to address the ligament as well as tendon insufficiency to gain a corrected arch. The success of such a procedure will depend upon adequate tendon and ligament reconstruction in a fully mobile deformity. Questions remain as to the adequacy of this ligament graft, and a stronger free ligament graft, as well as correction of any bony malalignment, may be required.

Total Ankle Arthroplasty With the Agility Prosthesis: Clinical and Radiographic Evaluation:

Background: Although ankle arthrodesis remains a standard operative procedure for disabling ankle arthritis, it has potential long-term problems. Total ankle arthroplasty offers preserved joint motion and may be a more favorable option in select patients. The purpose of this study was to report the intermediate-term clinical and radiographic results of total ankle arthroplasty using the Agility prosthesis. Methods: We retrospectively reviewed the results of total ankle arthroplasty in 41 consecutive patients (43 ankles). Evaluation included preoperative and postoperative questionnaires, physical examination, and radiographs. Results: At the time of followup, 38 patients (40 ankles) were available for review. The most common preoperative diagnoses included posttraumatic arthritis (24 of 40 ankles, 60%) and rheumatoid arthritis (eight of 40 ankles, 20%). Average age at surgery was 63 (range 32 to 85) years. Average followup was 44.5 (range 26 to 64) months. Preoperative and postoperative American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scores averaged 33.6 and 83.3, respectively, demonstrating significance (p < 0.001). Postoperative Medical Outcomes Study Short Form-36 (SF-36) Physical Component Summary (PCS) and Mental Component Summary (MCS) scores averaged 49.5 and 56.1, respectively. Although 34 of 40 ankles demonstrated radiographic lucency or lysis, the degree of involvement varied. Migration or subsidence of components was noted in 18 ankles. Overall, 37 of 38 patients were satisfied with the outcome of their surgery and would have the same procedure under similar circumstances. Conclusions: Agility total ankle arthroplasty results in a favorable clinical outcome and patient satisfaction in most patients at intermediate-term followup. However, total ankle arthroplasty is associated with potential complications and the need for subsequent operative intervention. Radiographic followup commonly reveals periprosthetic lucency, lysis, and component migration or subsidence, but this does not appear to adversely affect the intermediate-term clinical outcome. The long-term consequences of such radiographic findings are of concern, and surgeons and patients choosing this procedure need to be cautious.

Gross, Histological, and Microvascular Anatomy and Biomechanical Testing of the Spring Ligament Complex:

In recent years there has been an increased interest in the treatment of acquired pes planus. The breakdown of the medial longitudinal arch is most often seen at the talonaviculocalcaneal articulation. This suggests a relationship between the ligamentous complex at this articulation and acquired pes planus. This study was undertaken to gain a better understanding of the gross, histologic, and microvascular anatomy, as well as the biomechanics of the ligamentous structures surrounding the talonaviculocalcaneal articulation. Cadaver dissections of 38 fresh-frozen feet were performed. Detailed descriptions of the gross anatomy of the superomedial calcaneonavicular ligament, inferior calcaneonavicular ligament, and the superficial deltoid ligament were recorded. Their relationships to the posterior tibialis tendon and to the bones of the talonaviculocalcaneal articulation are described. The histology and microvascularity of these structures were also studied. Preliminary biomechanical testing was performed. It was found there are two definitive anatomic structures that are commonly called the spring ligament: the superomedial calcaneonavicular ligament (SMCN) and the inferior calcaneonavicular ligament (ICN). The SMCN ligament was found to have histologic properties that suggest significant load bearing. The histology of the ICN ligament suggests a pure tensile load function. The deltoid ligament and the posterior tibialis tendon had direct attachments to the SMCN ligament in all specimens. An articular facet composed of fibrocartilage was found in each SMCN ligament specimen. The microvascular structures showed an avascular articular facet present in the ligament. The biomechanical testing showed that the SMCN ligament and ICN ligament had strength similar to ankle ligaments. This study suggests this “spring ligament complex” has more of a “sling” function for the talar head. It is hoped that the better understanding of this region will add to our understanding of the etiology of pes planus and possible treatment alternatives.

Pes Planus in Patients with Posterior Tibial Tendon Insufficiency: Asymptomatic Versus Symptomatic Foot

Bilateral weightbearing anteroposterior and lateral radiographs were analyzed in 43 patients with a clinical diagnosis of posterior tibial tendon insufficiency by two independent observers. The radiographs of each patients asymptomatic foot was considered to serve as the control for the preexistance of pes planus. The radiographs were assessed for the severity of flatfoot deformity, the degree of talonavicular coverage, the talometatarsal angle, the calcaneometatarsal angle, the cuneiform to ground height and the cuneiform to fifth metatarsal height. Interobserver correlatations were assessed. Results indicated that there was a high interobserver correlation for the values measured, making these angles reproducible among observers. Strong correlations were found in the degree of severity of flatfoot deformity between the asymptomatic and symptomatic feet as well as the values used to assess pes planus (i.e., similar radiographic measurements on the opposite side). The data suggest that patients with posterior tibial tendon insufficiency often have a preexisting flatfoot. This substantiates our belief that a preexisting flexible flatfoot, although far from the determining factor, is one of several etiological factors in the development of posterior tibial tendon insufficiency.

Magnetic Resonance Imaging of the Lisfranc Ligament of the Foot

Early recognition of subtle Lisfranc injuries is important, because deformity and disability may develop after initially unremarkable radiographs. The authors studied 23 patients (mean age, 25.4 years) with a history of midfoot trauma with both radiographs and magnetic resonance imaging (MRI). When compared with the uninjured side, diastasis on radiographs ranged from 0 to 2 mm. The MRI revealed 2 intact ligaments, 3 complete tears, and 18 partial tears. All patients with complete tears had at least 2 mm more displacement between the second metatarsal and medial cuneiform, compared with the unaffected side. Because of the presence of complete or near complete rupture, seven patients underwent surgery, and the degree of rupture was confirmed. MRI of five cadaver specimens was also performed, disclosing discrete dorsal and plantar components. MRI was found to be useful in identifying Lisfranc ligament tears. If there is clear diastasis on weightbearing radiographs, MRI is not indicated. Whereas radiographic findings may be equivocal, however, MRI may accurately disclose the degree of ligament disruption.

Lateral Column Lengthening with Calcaneocuboid Fusion: Range of Motion in the Triple Joint Complex

Lengthening the lateral column of the foot has been shown to correct flatfoot deformity. In adults, however, lengthening leads to calcaneocuboid arthritis. Lateral column lengthening with calcaneocuboid fusion, which lengthens the lateral column of the foot and prevents calcaneocuboid arthritis, was investigated in a cadaver model to determine the remaining range of motion in the talonavicular and subtalar joints. Inversion/eversion motion was produced by tendon pulls and the range of motion was measured in three dimensions using a magnetic space tracker. After lateral column lengthening with calcaneocuboid fusion, 48% of talonavicular and 70% of subtalar joint range of motion were preserved. Analysis of the inversion and eversion ranges of motion suggests that the lengthening fusion limits eversion more than inversion. These findings demonstrate the need for clinical investigation of this procedure, which could preserve motion in the talonavicular and subtalar joints, correct deformity, and obviate calcaneocuboid arthritis.