An Ankle-Foot Orthosis With a Lateral Extension Reduces Forefoot Abduction in Subjects With Stage II Posterior Tibial Tendon Dysfunction.

STUDY DESIGN: Controlled laboratory, repeated measures. BACKGROUND: Posterior tibial tendon dysfunction is a common musculoskeletal problem that includes tendon degeneration and collapse of the medial arch of the foot (flatfoot deformity). Ankle-foot orthoses (AFOs) typically are used to correct flatfoot deformity. Correction of flatfoot deformity involves increasing forefoot adduction, forefoot plantar flexion, and hindfoot inversion. OBJECTIVES: To test whether a foot orthosis with a lateral extension reduces forefoot abduction in patients with stage II posterior tibial tendon dysfunction while walking. METHODS: The gait of 15 participants with stage II posterior tibial tendon dysfunction was evaluated under 3 conditions: a standard AFO, an AFO with a lateral extension, and a shoe-only control condition. Kinematic variables of interest were evaluated at designated time points in the gait cycle and included hindfoot inversion/eversion, forefoot plantar flexion/dorsiflexion, and forefoot abduction/adduction. A 3-by-4, repeated-measures analysis of variance (brace condition by gait phase) was used to compare variables across conditions. RESULTS: The AFO with a lateral extension resulted in a significantly greater change in forefoot adduction compared to the standard AFO (2.6°, P = .02) and shoe-only conditions (4.1°, P<.01) across all phases of stance. Forefoot plantar flexion was significantly increased when comparing the standard AFO and AFO with a lateral extension to the shoe-only condition. The AFO with the lateral extension also demonstrated significantly increased hindfoot inversion during the loading response and terminal stance phases. CONCLUSION: Off-the-shelf and standard AFOs have been shown to improve forefoot plantar flexion and hindfoot eversion, but not forefoot adduction. A lateral extension added to a standard AFO along the forefoot significantly improved forefoot adduction in participants with posterior tibial tendon dysfunction while walking.

Effect of ankle-foot orthotic devices on foot kinematics in Stage II posterior tibial tendon dysfunction.

BACKGROUND: Data are limited on the various orthotic devices available for patients with Stage II posterior tibial tendon dysfunction (PTTD). Foot kinematics observed while walking with an orthotic device are hypothesized to be associated with clinical outcomes and could be used to refine future device designs. METHODS: Fifteen subjects (age, 63.6 ± 6.8 years) with Stage II PTTD walked in the lab under four conditions: (1) shoe only (control condition), (2) shoe with a custom solid AFO (Arizona Co, Mesa, AZ), (3) shoe with a custom articulated AFO (Arizona Co, Mesa, AZ), and (4) shoe with an off-the-shelf AFO (AirLift, DJ Orthopedics). Kinematic data were collected to determine the degree of hindfoot inversion, forefoot plantarflexion (reflective of raising the MLA), and forefoot adduction associated with each condition. RESULTS: The custom articulated device was associated with greater hindfoot inversion compared to the shoe only condition at loading response (p = 0.002), mid-stance (p < 0.001), and terminal stance (p = 0.02). The custom articulated device, custom solid device, and off-the-shelf device were associated with greater forefoot plantarflexion compared to the shoe only condition across all four phases of stance. There were no differences between any of the devices and the shoe condition associated with forefoot adduction. CONCLUSION: The custom devices were associated with greater hindfoot inversion and forefoot plantarflexion compared to walking with only a shoe, while the off-the-shelf device was associated with forefoot plantarflexion but no change in hindfoot motion. None of the devices corrected forefoot abduction compared to the shoe only condition. CLINICAL RELEVANCE: The current biomechanical data may aid in understanding the clinical outcomes seen using these devices as well as provide data to support new designs.

Lateral tibial plateau fracture depression as a predictor of lateral meniscus pathology.

The goal of this study was to determine if the degree of lateral tibial plateau fracture depression on computed tomography (CT) images predicted the presence of lateral meniscus tears. The study group comprised 85 patients who sustained a lateral tibial plateau fracture and underwent open reduction and internal fixation by the same surgeon. Degree of plateau depression was measured in millimeters by CT. Operative reports were retrospectively reviewed to determine if the lateral meniscus tear was intact or torn at the time of surgery. Twenty-eight patients had a lateral meniscus tear noted at the time of surgery. No significant differences existed in gender, mechanism or energy level of injury, Schatzker classification, or type of fracture among patients with a lateral meniscal tear as compared to those without a tear. Patients with > or =10 mm of plateau depression had an eight-fold increase in risk of having a lateral meniscus tear compared to those with <10 mm of depression. Patients younger than 48 years had a four-fold increase in risk of having a lateral meniscus tear than older patients.This study demonstrated an association between the amount of tibial plateau depression and the likelihood of a lateral meniscus tear. These findings may be used to predict those who have sustained a tear of the lateral meniscus and to advise the surgeon to prepare for a repair. Further prospective studies using magnetic resonance imaging as a tool to evaluate the extent of soft tissue injuries in plateau fractures is needed.