Kitaoka, Harold B.

Background: Tibiotalar arthrodesis (TTA) is a common operation for end-stage ankle arthritis. Elevated body mass index (BMI) is believed to contribute to complications following TTA. Previous studies involved national registries or small, underpowered cohorts. This study aimed to determine the effects of elevated BMI on nonunion and complication rates following TTA with a large cohort from a single academic institution. Methods: A retrospective study identified 514 patients (527 ankles) who underwent primary TTA from 2005-2017. Mean age was 60 years. Patients were stratified by BMI according to the World Health Organization classification. A reference group of 203 patients (208 ankles) included normal weight or mildly overweight patients (BMI 18.5 to <30). Ankle radiographs were evaluated to determine union or nonunion. Other outcomes included revision TTA, reoperations, subsequent adjacent joint arthrodesis, infection, and readmission. Data were analyzed using Pearson χ 2 and odds ratios for categorical variables. Analysis of variance and Kaplan-Meier estimation assessed continuous variables and time-to-event outcomes, respectively. Mean follow-up was 34.3 months. Results: Obesity class III patients had elevated risk of complications compared with normal weight patients including nonunion (odds ratio [OR] 3.96, P = .002), revision (OR 3.69, P = .03), superficial infection (OR 9.36, P = .002), and readmission (OR 10.90, P = .01). Superficial infection rates were elevated in class I (OR 6.36, P = .007) and readmissions in class II (OR 9.98, P = .01). No differences were found in reoperation ( P = .448), symptomatic implant removal ( P = .805), adjacent joint arthrodesis ( P = .353), or deep infection ( P = .507) rates. Discussion: In this retrospective review after TTA, increased rates of nonunion, revision, superficial infection, and readmission were found in obesity class III patients, compared with the reference group of normal weight or mildly overweight patients. Superficial infection rates were likewise relatively elevated in class I and readmission rates in class II patients.

Abstract Electromyography (EMG) measurement has been the one of the major sources of information to understand the neuromuscular control of human locomotion, while a limited amount of knowledge is available due to its complicate signal structure. Other measurable parameters may be of little value in extracting the neuromuscular information without having a precise mechanical relationship.

Outcome measures evaluate various aspects of patient health, and when appropriately utilized can provide valuable information in both clinical practice and research settings. The orthopedic community has placed increasing emphasis on patient-reported outcome measures, recognizing their value for understanding patients’ perspectives of treatment outcomes. Patient-reported outcomes are information directly reported by patients regarding their perceptions of health, quality of life, or functional status without interpretation by healthcare providers. The American Orthopaedic Foot & Ankle Society (AOFAS) supports the use of validated patient-reported outcome (PRO) instruments to assess patient general health, functional status, and outcomes of treatment. It is not possible to recommend a single instrument to collect quality orthopedic data as the selection is dependent on the population being examined and the question being asked. We support the use of the PROMIS Physical Function Computerized Adaptive Test (PF CAT) or Lower Extremity Computerized Adaptive Test (LE CAT), which can be assessed with other domains such as Pain Interference. In addition, a disease-specific measure can be used when available.

We studied retrospectively the results in 24 patients (25 feet) who had been treated by subtalar arthrodesis with internal compression for post-traumatic arthritis from 1988 to 1992. Fifteen patients were men (16 feet) and nine (9 feet) were women. Their mean age was 43 years (22 to 68), and the average duration of follow-up was four years (2 to 6). A single compression screw was used in all feet and iliac-crest bone grafting in ten. Union was achieved in 24 of the 25 feet (96%). Based on a clinical scale the results were excellent in 10 feet, good in 7, fair in 6, and poor in 2 and on the Angus and Cowell score they were good in 19 feet, fair in 4, and poor in 2. The two poor results were due to nonunion in one patient and reflex sympathetic dystrophy in the other. One reoperation was performed for nonunion. Eighteen patients (18 feet) were satisfied with the results, four were satisfied with reservations, and three were dissatisfied. Progressive ankle and midfoot arthritis did not occur in the absence of pre-existing degenerative changes in these joints. We conclude that isolated subtalar arthrodesis with internal compression was effective treatment for post-traumatic subtalar arthritis. Iliac-crest bone grafting was not routinely required.

We performed distal chevron osteotomy of the second, third, or fourth metatarsal for painful plantar callosities in 19 non-rheumatoid patients (16 women, 3 men; 21 feet); their mean age was 59 years (32 to 85). The mean follow-up was four years (2 to 7). The overall results were good in 16 feet, fair in two, and poor in three, with four patients still having painful plantar callosities. There was union in all feet, but transfer metatarsalgia developed in three and three required an orthosis. Distal chevron osteotomy for intractable plantar callosities was successful both clinically and radiologically in most patients.

Background: One factor believed to contribute to the development of hallux valgus is an abnormality in collagen structure and makeup of the medial collateral ligament (MCL) of the first metatarsophalangeal joint (MTPJ). We hypothesized that the mechanical properties of the MCL in feet with hallux valgus are significantly different from those in normal feet and that these differences may be related to alterations in the type or distribution of collagen fibers at the interface between the MCL and the bone. Materials and Methods: Seven normal fresh-frozen cadaver feet were compared to four cadaver feet that had hallux valgus deformities. The MCL mechanical properties, structure of collagen fibers, and content proportion of type I and type III collagen were determined. Results: The load-deformation and stress-strain curves were curvilinear with three regions: laxity, toe, and linear regions. Laxity of the MCL in feet with hallux valgus was significantly larger than that of normal feet ( p = 0.022). Stiffness and tensile modulus in the toe region in feet with hallux valgus were significantly smaller than those in normal feet ( p = 0.004); however, stiffness and tensile modulus in the linear region were not significantly different. The MCL collagen fibrils in the feet with hallux valgus had a more wavy distribution than the fibrils in the normal feet. Conclusions: In general, strong staining for collagen III and to a lesser extent, collagen I was observed at the interface between the MCL and bone in the feet with hallux valgus but not in the normal feet. These results indicate that the abnormal mechanical properties of the MCL in feet with hallux valgus may be related to differences in the organization of collagen I and collagen III fibrils.

Background: Assessing patients with foot and ankle disorders by observation of gait is dependent on the examiner's experience and cannot provide information about three-dimensional movement, forces, or motion of segments of the foot. Gait analysis models usually consider the foot as a rigid body and study the foot and ankle as a unit. These models are adequate to describe ankle sagittal plane mechanics but are limited in their ability to provide accurate analysis in the other planes or of segments of the foot. They are, therefore, less effective for objective assessment of foot and ankle disorders than multi-segment foot models. Methods: We performed gait analysis using foot-specific analysis methods and evaluated kinematics, ground reaction forces, temporal force factors, and time-related gait factors in 20 normal subjects during level walking. Eleven reflective markers were applied to the foot and leg, and ten cameras and force plates were used. Subjects were tested in athletic shoes. Results: A three-segment model was constructed to determine three-dimensional motion in the sagittal, coronal, and transverse planes. This model enabled the determination of calcaneal-tibial (ankle-hindfoot complex) and metatarsal-calcaneal (midfoot) movement in three planes. Ground reaction forces, temporal force factors, cadence, stance time, swing time, and percentage of stance time were determined. Conclusions: These data provide baseline information for assessment of patients with disorders of the ankle and foot.

Background: It is necessary to have an understanding of ankle and hindfoot motion and stability to accurately diagnosis and treat ankle-hindfoot disorders. Methods: We devised an ankle ligament testing apparatus to more critically determine ankle stability in all planes with a constant rotational force applied (inversion, eversion, internal rotation, external rotation) throughout the range of sagittal plane motion in 13 cadaver specimens. Three-dimensional kinematics were determined with a magnetic tracking device. Results: With inversion force applied, calcanealtibial inversion was greatest in maximal plantarflexion (mean 22.1 ± 6.0 degrees) and gradually decreased with dorsiflexion, which indicated that the ankle had the most inversion instability in plantarflexion. With eversion force applied, calcaneal-tibial eversion gradually increased with increasing dorsiflexion to 12.7 ± 7.4 degrees indicating that the most eversion instability was in dorsiflexion. With internal rotation force applied, calcaneal-tibial internal rotation from plantarflexion to neutral ankle position increased. With external rotation force application, external rotation from neutral to maximal dorsiflexion increased. Conclusions: Ankle laxity was not constant but varied depending on the plantarflexion-dorsiflexion position and the direction of the applied force. The degree of ankle laxity was greater with inversion and internal rotation torque. Variation in laxity between specimens was observed, consistent with previous reports. These data indicate that the ankle is less stable in plantarflexion when inversion and internal rotation forces are applied. This may explain why the lateral ankle ligaments are most prone to injury in this position. The ankle was less stable in dorsiflexion when eversion and external rotation forces were applied. This is consistent with the observation that deltoid ligament injuries occur in the neutral to dorsiflexion position. The study demonstrates the importance of examining patients with suspected ankle ligament injuries in several ankle positions. The ankle testing device has potential application for in vivo testing of patients with suspected ankle ligament instability.

Eleven fresh-frozen cadaver foot specimens were tested to define changes in tarsal alignment associated with flatfoot, or pes planus, a common clinical problem. The three-dimensional position of four bones (talus, calcaneus, navicular, and first metatarsal) relative to the fixed tibia was determined with a magnetic tracking system in the intact foot and flatfoot conditions. In the flatfoot, the average metatarsal-to-talar position difference was 11.7° ± 4.4° in abduction ( P < 0.0001), 10.4° ± 3.6° in dorsiflexion ( P < 0.0001), and 10.9° ± 6.0° in eversion ( P < 0.0001) compared with the intact foot. The average calcaneal-to-talar position difference was 2.2° ± 2.6° in abduction ( P = 0.0171) and 2.7° ± 2.0° in eversion ( P = 0.0012) compared with the intact foot. The average navicular-to-talar position difference was 13.6° ± 5.0° in abduction ( P < 0.0001), 10.5° ± 6.6° in dorsiflexion ( P = 0.0004), and 8.1° ± 3.8° in eversion ( P < 0.0001) compared with normal. The average talar-to-tibial position difference was −8.2° ± 3.2° in dorsiflexion ( P < 0.001) compared with the intact foot. The average arch height difference was 6.0 ± 2.7 mm ( P < 0.0001) less than the normal condition. The deformity associated with flatfoot is complex and occurs in multiple joints and in all three planes. An understanding of the normal and pathologic (flatfoot) conditions is necessary to surgically restore appropriate alignment and function in hindfoot reconstruction operations.

Twenty patients (14 women and 6 men) (23 feet) had a single oblique osteotomy operation of the 2nd, 3rd, or 4th metatarsal without fixation during an 8-year period. The mean age was 46 years (range, 21–64 years). Each patient had a painful intractable plantar keratosis preoperatively. The average follow-up was 10 years (range, 3–14 years). Postoperatively, reoperation was performed in four feet because of painful callosities. For 13 of the 19 feet that did not have reoperation, patients were limited in footwear or required a shoe insert. Overall results were good for 10 feet, fair for 7 feet, and poor for 6 feet. The only complication was a deep infection that occurred in one foot (good result). Nonunion occurred in one foot and delayed union in one. The average decrease in metatarsal length after osteotomy was 6 ± 6 mm. The single oblique lesser metatarsal osteotomy may be successful, but one half of the patients continued to have some degree of pain and most patients had limitations in footwear. Overall results were disappointing, and patients who are offered this procedure should be advised of its limitations.