J Orthop Sports Phys Ther 1991;14(2):70-74.

Key Words: Ankle, foot structure, alignment reliability

Study Design: Case report with repeated measures. Objectives: To describe the effects of a tendo-Achilles lengthening (TAL) and total contact casting (TCC) on wound healing, motion, plantar pressure, and function in a patient with diabetes mellitus, peripheral neuropathy, neuropathic ulcer, and limited dorsiflexion range of motion (DFROM). Background: Limited DFROM has been associated with increased forefoot pressures and skin breakdown. A TAL was expected to increase DFROM and reduce forefoot pressures during walking, but the influence on muscle performance and function was unknown. Methods and Measures: The patient was a 42-year-old man with a 20-year history of type 1 diabetes (NIDDM) and a recurrent neuropathic plantar ulcer. Outcome measures were DFROM, isokinetic plantar flexor muscle peak torque, in-shoe and barefoot peak plantar pressure, physical performance test (PPT) score, and peak ankle and hip moments during walking obtained from an automated gait analysis. All tests were completed pre-TAL, 8 weeks post-TAL (after immobilization in a TCC), and 7 months post-TAL. Results: The wound healed in 40 days. The TAL resulted in a sustained increase in DFROM (0 to 18°). Plantar flexor peak torque was reduced by 21% 8 weeks after the TAL compared with the torque before surgery but recovered fully at 7 months. Seven months following TAL, in-shoe forefoot peak plantar pressure was reduced by 55%, barefoot pressure decreased by 14%, PPT score increased by 24%, peak ankle plantar flexor moment remained decreased by 30%, and the peak hip flexor moment increased by 41% during walking. Conclusion: For this patient, a TAL resulted in short-term deficits in peak plantar flexor torque, but a 7-month follow-up showed improvements in ankle DFROM, walking ability, and a decrease in forefoot in-shoe peak plantar pressure.

J Orthop Sports Phys Ther. 2000;30(2):85-90.

Key Words: dorsiflexion range of motion, peak plantar pressure, physical performance test, plantar flexor moment

Study Design: Descriptive study to compare relationships between muscle performance measures in 2 subject groups. Objectives: To determine the relationships between plantar flexor (PF) muscle stiffness, strength (concentric peak torque), and dorsiflexion (DF) range of motion (ROM) in subjects with diabetes who have peripheral neuropathy (n = 17, 10 men, 7 women; age = 58 ± 11 years) and age-matched controls (n = 17, 10 men, 7 women; age = 62 ± 6 years). Background: The relationships between muscle stiffness, strength, and joint ROM have not been clearly established. Furthermore, the effect of neuromuscular pathology on these relationships is unknown. Methods and Measures: PF stiffness and strength measurements were obtained with an isokinetic dynamometer. DF ROM was measured with a goniometer. A Pearson correlation matrix was constructed for each subject group using stiffness, strength, and ROM variables. The percent contribution of passive torque to total torque was computed at 2 joint angles. Results: In subjects with diabetes and peripheral neuropathy (DM-PN) peak concentric PF torque was positively correlated with passive torque at 5° DF (r = 0.77), Stiffness #1 (r = 0.58), and Stiffness #2 (r = 0.50). The percentage of passive PF torque at 5° DF was greater in subjects with DM-PN, compared to control subjects (29.3 ± 9.4% versus 12.6 ± 5.9%). Conclusions: The positive correlation between PF stiffness and strength, and the greater percentage of passive PF torque in subjects with DM-PN suggest that patients with decreased strength may use passive torque to maximize total torque. Therefore, treatment methods designed to decrease stiffness should be used cautiously.

J Orthop Sports Phys Ther. 2000;30(8):473-483.

Key Words: active and passive tension, ankle joint, biomechanics

This clinical perspective describes the application of plantar pressure assessment in footwear and insert design. First, the rationale and evidence for using pressure assessment to assist in the design of footwear for patients with diabetes is described. I discuss 2 important measures obtained from pressure assessment: peak pressure, because it represents the magnitude of potential mechanical stresses that can contribute to skin breakdown, and contact area, because this identifies the treatment areas. Using measures obtained from pressure assessment, guidelines are presented to maximize contact area of the insert to the foot and reduce highest peak pressures on the skin, with the goal of preventing skin breakdown. Second, a rationale and guidelines are presented for the application of plantar pressure assessment in the evaluation and design of footwear for people without impairments (ie, the general public). Finally, future applications of pressure assessment to improve the design and fit of shoes are discussed. Benefits and limitations of using pressure assessment to assist in footwear design are addressed throughout.

J Orthop Sports Phys Ther. 1999;29(12):747-755.

Key Words: diabetes, orthotic devices, pressure, shoes, ulcer

Physical therapists use various gait training strategies to reduce stress on the lower extremities, but we could find no description or evaluation of the step-to gait using a cane. The purpose of this study was to evaluate the effect of a step-to gait pattern and a cane on peak plantar pressures on the forefoot and the heel. Ten healthy subjects were evaluated (five females, five males, mean age = 24.6 ± 4.9 years). In addition, one subject with peripheral neuropathy was tested to determine if a patient could be trained to use the step-to walking pattern and show similar results. All subjects were instructed in four walking conditions: step-to with and without a cane and step-through with and without a cane. Walking speed during the step-through pattern (normal walking) was matched to the speed of the step-to pattern. For the 10 healthy subjects, peak plantar pressures and walking speed of each of the four conditions were compared using a 2 x 2 repeated measures analysis of variance. One factor was gait pattern and one factor was use of a cane. Peak plantar pressures decreased an average of 53% on the forefoot but increased an average of 14% on the heel when subjects walked using step-to gait compared with a step-through gait. There was no effect due to use of a cane or walking speed between the conditions. The patient with peripheral neuropathy demonstrated a similar pattern but greater magnitude of changes compared with the healthy subjects. The foot initiating the step-to pattern showed a reduction in peak plantar pressures on the forefoot, probably because the foot remained flat during stance phase and a large push-off was not required. The step-to pattern, however, results in a slower and less symmetrical gait. The use of a step-to gait may be beneficial for patient populations that need to reduce plantar pressures on the forefoot.

J Orthop Sports Phys Ther. 1998;28(3):139-145.

Key Words: foot, biomechanics, gait, diabetes

Many injuries to the foot appear to be caused by repeated, excessive plantar pressures. In-shoe pressure systems are capable of measuring pressures at the interface between the shoe or orthotic and the plantar foot during a given functional activity. The purpose of this article is to describe the use of an in-shoe pressure system as a tool to aid physical therapists in the management of patients with foot problems as a result of excessive plantar pressures. Case histories are provided that describe the application of an in-shoe pressure device in the management of one patient with a neuropathic ulcer and one patient with metatarsalgia. A discussion of the primary clinical and equipment considerations of using this type of device is included.

J Orthop Sports Phys Ther. 1995;21(6):328-336.

Key Words: foot pressure, diabetes, arthritis, biomechanics

Many athletes develop shin splints after athletic activity. The purpose of this case report is to describe the treatment of a patient with posteromedial tibial pain (shin splints) who habitually ran with a forefoot contact running style. The 20-year-old male patient, who played volleyball and basketball about 7 hours a week, complained of pain in the middle one-third of the posteromedial tibia after an acute but prolonged episode of running. Routine observational analysis and in-shoe pressure analysis of the patient's running style showed that he habitually ran on his toes with an absence of heelstrike (forefoot contact running). After instructing the patient on heel-toe running, he no longer complained of posteromedial tibial bone pain. Several possible reasons are proposed for the reduction of leg pain following cessation of forefoot contact running. This case report proposes forefoot contact running as a possible contributor to posteromedial shin splints and that a change in running style may be the optimal treatment for some patients.

J Orthop Sports Phys Ther. 1994;20(2):98-102.

Key Words: shin splints, overuse injury, running