Improved ankle push-off power following cheilectomy for hallux rigidus: a prospective gait analysis study.

BACKGROUND: There is limited objective scientific information on the functional effects of cheilectomy. The purpose of this study was to test the hypothesis that cheilectomy for hallux rigidus improves gait by increasing ankle push-off power. METHODS: Seventeen patients with symptomatic Stage 1 or Stage 2 hallux rigidus were studied. Pre- and postoperative first metatarsophalangeal (MTP) range of motion and AOFAS hallux scores were recorded. A gait analysis was performed within 4 weeks prior to surgery and repeated at a minimum of 1 year after surgery. Gait analysis was done using a three-dimensional motion capture system and a force platform embedded in a 10-m walkway. Gait velocity sagittal plane ankle range of motion and peak sagittal plane ankle push-off power were analyzed. RESULTS: Following cheilectomy, significant increases were noted for first MTP range of motion and AOFAS hallux score. First MTP motion improved an average of 16.7 degrees, from means of 33.9 degrees preoperatively to 50.6 degrees postoperatively (p<0.001). AOFAS hallux score increased from 62 to 81 (p<0.007). As demonstrated through gait anaylsis, a significant increase in postoperative peak sagittal plane ankle push-off power from 1.71±0.92 W/kg to 2.05±0.75 W/kg (p<0.04). CONCLUSION: In addition to clinically increased range of motion and improved AOFAS Hallux score, first MTP joint cheilectomy produced objective improvement in gait, as measured by increased peak sagittal-plane ankle push-off power.

Effect of heating on the mechanical properties of insole materials.

BACKGROUND: The most common method of customizing shoe insoles to the shape and surface of the foot is to heat and then mold the materials. The effect of heating on the mechanical properties of these materials is unknown. METHODS: The properties of individual and common combinations of insole materials were tested before and after heating. Individual materials tested were soft Plastazote (SP), medium Plastazote (MP), Puff (F), and Nickelplast (N); combinations of materials that were tested were SP + F and MP + F, each with and without Poron (P). Three samples of each were tested five times. Materials were heated and then compressed with an MTS servohydraulic device. Load transmission and percent compression at maximal load were measured on single materials and their combinations. Stress-strain curves were measured. RESULTS: Compared to unheated material, the heated material transmitted higher forces. After heating, the combinations transmitted maximal load at a lower percentage of compression (i.e., became stiffer). Heating also changed the stress-strain curves of the three-material combinations, causing them to transmit maximal pressure at a lower strain. CONCLUSION: Heating insole materials changed their mechanical properties. The materials became stiffer and less effective in the attenuation of applied forces. CLINICAL RELEVANCE: The common practice of heating insole materials to improve their contact with the foot reduced the pressure-reducing properties of the materials, which may decrease their clinical effectiveness.

Excellent outcomes for adults who experienced early standardized treadmill training during acute phase of recovery from stroke: a case series.

OBJECTIVE: To describe gait outcomes, including assistive device use and incidence of falls, in a group of adults post stroke who received early standardized treadmill training (ESTT) in the acute phase of rehabilitation. DESIGN: A case series of 18 individuals post stroke with varied lesion size, location, and comorbidities. SETTING: Inpatient rehabilitation unit. INTERVENTION: Daily 30-minute sessions of ESTT initiated before overground training in the acute rehabilitation period. OUTCOME MEASURES: Three-dimensional gait analysis, 6-minute walk test (6MWT), assistive device inventory, and fall history. RESULTS: Gait analysis revealed better temporal and spatial symmetry than have been previously documented. Twelve participants walked at speeds of greater than 0.80 m/s and 10 walked without the use of an assistive device or orthoses. Mean 6MWT distance was 322.42 m (±114.33). Thirteen participants (72%) reported no falls over a 6-month period. CONCLUSION: These outcomes far surpass the current data reported in the literature for this patient population and were achieved by the application of an intervention that was feasible in the acute rehabilitation setting.

James Pat Evans, MD, 1930-2019.

This biographical sketch of Dr. J. Pat Evans commemorates the life and contributions of one of the most influential sports surgeons in the history of orthopedic surgery, drawing on articles written in remembrance of him and his contributions to orthopedic surgery and sports medicine.

Ruth Jackson, MD, 1902-1994.

This article commemorates Dr. Ruth Jackson for her contributions to orthopedic surgery and her status as a trailblazer for women in orthopedic surgery, becoming the first female member of the American Academy of Orthopedic Surgeons. She died on August 28, 1994, at the age of 91.

Robert Wilson Jackson, MD (1932-2010).

This article commemorates the life and contributions of one of the most influential sports surgeons in the history of orthopedic surgery, Dr. Robert Jackson.

Prospective study of the effect on gait of a two-component total ankle replacement.

BACKGROUND: The purpose of this study was to evaluate the functional outcome as measured by prospective gait analysis of patients undergoing total ankle arthroplasty using a 2-component Salto Talaris total ankle prostheses with a fixed polyethylene bearing. METHODS: Twenty-one patients with severe ankle arthritis who underwent unilateral total ankle arthroplasty using a 2-component Salto Talaris device with a fixed polyethylene bearing were studied prospectively. Mean age was 69 years in 16 female and 5 male patients, and mean follow-up was 37.2 (range, 24-50) months. Three-dimensional gait analysis was performed using a 12-camera digital-motion capture system preoperatively and repeated at a minimum of 2 years postoperatively. Temporospatial measurements included velocity, cadence, step length, and support times. Measured kinematic parameters included sagittal plane range of motion of the ankle, knee, and hip. Kinetic parameters included sagittal plane ankle power and ankle plantarflexion moment. RESULTS: There was significant improvement in temporospatial parameters, including step length (P = .014) and walking velocity, which increased from 0.9 to 1 m/s (P = .01). Kinematic results showed sagittal plane range of motion of the ankle increased significantly from a mean of 15.8 degrees preoperatively to 20.6 degrees (P = .00005) postoperatively with the increase occurring primarily in dorsiflexion. Kinetic results showed ankle peak power increased from a mean of 0.7 Nm/kg to 1.1 Nm/kg (P = .004). CONCLUSIONS: A prospective study of gait in patients undergoing total ankle arthroplasty using a 2-component Salto Talaris device with a fixed polyethylene bearing showed, at midterm follow-up, significant improvements in multiple parameters of gait when compared to the patients' own preoperative function. LEVEL OF EVIDENCE: Level IV, prospective case series.

Hindfoot motion following STAR total ankle arthroplasty: a multisegment foot model gait study.

BACKGROUND: One of the rationales for total ankle arthroplasty (TAA) is that it may retard the changes of hypermobility and accelerated arthritis in the hindfoot after ankle arthrodesis. Until recently, it has not been possible to quantify or even objectively demonstrate biomechanical findings to substantiate the theory that postsurgical biomechanical changes in the ankle produce changes in the kinematics of the hindfoot. Standard gait analysis has treated the foot as a single biomechanical unit. This study was undertaken to describe the hindfoot motion following Scandinavian Total Ankle Replacement (STAR) TAA by using multisegment foot model gait analysis. METHODS: Forty-six patients with a mean age of 66 years underwent a 3D gait analysis following TAR. Mean interval between surgery and gait analysis was 4.9 years (range 2 to 9). The contralateral limb was used as control for each patient. Temporospatial variables and kinematic parameters were studied. RESULTS: Temporospatial results showed statistically significant differences. Stance time on the affected side was 61.1% ± 2.2% of the gait cycle compared to 63.2% ± 2.1% for the unaffected side. Step length was 55.6 cm ± 10 on the affected side compared to 53.9 cm ± 10 for the unaffected side. Kinematics results were statistically significant: Ankle range of motion (ROM) on the arthroplasty side was 16.8 ± 4.5 degrees compared to 23.6 ± 5.0 on the unaffected side. Sagittal plane ROM was 12.7 ± 4.2 degrees on the arthroplasty side and 17.3 ± 3.5 degrees on the unaffected side. Coronal plane ROM was 4.7 ± 2.4 degrees on the arthroplasty side and 7.5 ± 2.4 degrees on the unaffected side. Transverse plane ROM on the arthroplasty side was 4.1 ± 1.5 degrees and 4.9 ± 1.6 on the unaffected side. CONCLUSION: This study showed that, in addition to previously documented diminution in sagittal plane motion and gait velocity, some of the residual abnormalities of gait following TAR were comprised of differences in hindfoot function. These results relate to the growing recognition of the importance of understanding hindfoot mechanics apart from those of the tibiotalar joint. LEVEL OF EVIDENCE: Level III, comparative case series.

Changes in gait following the Scandinavian Total Ankle Replacement.

BACKGROUND: There is a resurgence of popularity with regard to total ankle arthroplasty, although there are limited data documenting the effect of total ankle arthroplasty on ankle joint motion, gait, or ankle function. The purpose of this study was to perform a prospective evaluation of the effect of the Scandinavian Total Ankle Replacement on gait. METHODS: We prospectively studied fifty consecutive patients with advanced ankle arthritis who underwent unilateral total ankle arthroplasty with the Scandinavian Total Ankle Replacement ankle prosthesis. Three-dimensional gait analysis was performed with use of a twelve-camera digital-motion capture system. Kinetic parameters were collected with use of two force plates. Temporal-spatial measurements included stride length and cadence. The kinematic parameters that were measured included the sagittal plane range of motion of the ankle, knee, and hip. The kinetic parameters that were studied included ankle plantar flexion-dorsiflexion moment and sagittal plane ankle power. The mean period of follow-up was forty-nine months (range, twenty-four to 108 months). RESULTS: Temporal-spatial analysis showed that walking velocity increased as a function of increases in both cadence and stride length, and to significant levels for each. Kinematic analysis showed that ankle range of motion increased from a mean of 14.2° to 17.9° (p < 0.001), with the increase coming from increased plantar flexion. Increased motion was also measured at the hip and knee. Significant increases were found in ankle power (from 0.69 to 1.00 W/kg [p < 0.001]) and ankle plantar flexion moment (from 0.88 to 1.09 Nm/kg [p < 0.001]). CONCLUSIONS: This study demonstrated that, at the time of intermediate-term follow-up and in comparison with the effects of ankle arthrodesis on gait as reported in previous studies, total ankle arthroplasty was associated with a more normal ankle function and a more normal gait, both kinetically and in terms of temporal-spatial parameters. More importantly, the study demonstrated marked improvement in multiple, objective parameters of gait following total ankle arthroplasty as compared with the patient's own preoperative function. The long-term maintenance of the gait improvements will require further study.