Hindfoot motion following reconstruction for posterior tibial tendon dysfunction.

INTRODUCTION: Due to advances in technology, segmental gait analysis of the foot is now possible and can elucidate hindfoot deformity in persons with posterior tibial tendon dysfunction (PTTD). This study evaluated the motion of the hindfoot and ankle power following surgical reconstruction for PTTD utilizing a segmental foot model during gait. MATERIALS AND METHODS: Twenty patients who underwent posterior tibial tendon reconstruction for Stage 2 PTTD using transfer of the flexor digitorum longus tendon to the navicular tuberosity, reconstruction of the calcaneo-navicular ligament complex, and a medial displacement calcaneal osteotomy were evaluated at a minimum followup of 1 year. Three-dimensional gait analysis was performed utilizing a 4-segment foot model. Temporal-spatial parameters included walking velocity, cadence, step length, and single support time. Sagittal, coronal, and transverse hindfoot motion with respect to the tibia/fibula and ankle power was calculated throughout the gait cycle. RESULTS: Walking velocity, cadence, and step length were not significantly different between the study subjects and the normal control group. Study patients did show a significantly smaller single support time on both the affected and unaffected limbs compared to controls. There was no statistical difference in plantarflexion-dorsiflexion, varus-valgus, or ankle push-off power between the affected and unaffected sides of the study subjects, or between the affected side and the controls. CONCLUSION: In this preliminary postoperative study, surgical reconstruction for PTTD effects quantifiable objective improvement in walking velocity, hindfoot motion and power.

Locomotor treadmill training with partial body-weight support before overground gait in adults with acute stroke: a pilot study.

OBJECTIVE: To investigate the impact of locomotor treadmill training with partial body-weight support (BWS) before the initiation of overground gait for adults less than 6 weeks poststroke. DESIGN: Parallel group, posttest only. SETTING: Inpatient rehabilitation center. PARTICIPANTS: Adults after first stroke admitted to an inpatient rehabilitation unit: treadmill group (n=7) and comparison group (n=7). INTERVENTIONS: Locomotor treadmill training with partial BWS or traditional gait training methods. MAIN OUTCOME MEASURES: Gait kinematics, symmetry, velocity, and endurance at least 6 months postinsult. RESULTS: Data from 3-dimensional gait analysis and 6-minute walk test (6MWT) supported improved gait for adults postacute stroke who practiced gait on a treadmill before walking over ground. Gait analysis showed increased knee flexion during swing and absence of knee hyperextension in stance for the treadmill group. In addition, more normal ankle kinematics at initial contact and terminal stance were observed in the treadmill group. Improved gait symmetry in the treadmill group was confirmed by measures of single support time, hip flexion at initial contact, maximum knee flexion, and maximum knee extension during stance. The treadmill group also walked further and faster in the 6MWT than the comparison group. CONCLUSIONS: Application of locomotor treadmill training with partial BWS before overground gait training may be more effective in establishing symmetric and efficient gait in adults postacute stroke than traditional gait training methods in acute rehabilitation.

Physical properties, durability, and energy-dissipation function of dual-density orthotic materials used in insoles for diabetic patients.

BACKGROUND: Patients with neuropathic conditions may develop plantar bony deformities through neuropathic collapse, frequently placing the skin and soft tissues at risk. Orthoses have been used to accommodate and distribute plantar pressures over a large surface area, thereby minimizing peak loading pressures in small regions and reducing the risk of ulceration. METHODS: A previously described bony prominence model (Brodsky et al.) was used to test the pressure-absorbing and force-transmission properties of various orthotic material combinations used in our outpatient clinic. Six materials were tested in five combinations of materials for their compressive properties: [MS]: medium plastazote (M) + soft plastazote (S); [MN]: medium plastazote (M) + nickelplast (N); [NP] nickelplast (N) + Poron (P); [MO] medium plastazote (M) + Spenco (O); and [MC] medium plastazote (M) + P-cell (C). Materials were tested for 100,000 cycles using a materials-testing system (MTS) apparatus (MTS Systems Corporation, Cary, NC) and software. Stress-strain curves comparing the measured peak pressure to the elastic deformation, or the percentage of compression a material experiences with respect to its original thickness, were plotted for each orthotic combination. RESULTS: For MS, MN, MO, and to a lesser extent, MC, a trend was noted for decreased elastic deformation with increased testing. Additionally, the peak pressures before and after testing for each 10,000 testing cycle for each of the orthotic combinations were plotted. For both MN and NP, no demonstrable difference was noted in the peak pressures in the pretesting and post-testing for the 100,000 cycles. The MO showed a trend for increased peak pressures after each testing cycle. Both the MC and MS peak pressures markedly increased with respect to pretesting value. Also, the MN, MO, and MS all showed an overall trend for increased load cell values with increasing cycles at fast loading. CONCLUSIONS: These data showed that some orthotic combinations are more effective than others at reducing peak pressures during compression testing using our bony prominence model. Further studies are needed to test the orthotic combinations for shear and combined shear and compression modes.

Prospective gait analysis in patients with first metatarsophalangeal joint arthrodesis for hallux rigidus.

BACKGROUND: Arthrodesis of the first metatarsophalangeal (MTP) joint is a common procedure with a proven long-term success rate. However, there is limited scientific information on its functional results. There is little data in the literature about changes in gait parameters after first MTP joint arthrodesis. The purpose of this study was to objectively evaluate the effects of first MTP joint arthrodesis on gait. METHODS: Twenty-three patients with symptomatic hallux rigidus refractory to nonoperative treatment were treated with first MTP joint arthrodesis. A prospective gait analysis study was performed on all patients at an average of 8.6 days before surgery and then again at least 1 year postoperatively. Preoperative and postoperative data from the patients were compared to determine differences in clinically relevant temporal-spatial, kinematic, and kinetic parameters of gait. RESULTS: There were three statistically significant changes in gait: increases in maximal ankle push-off power and single-limb support time on the involved extremity, and a decrease in step width. CONCLUSIONS: First MTP joint arthrodesis produces objective improvement in propulsive power, weightbearing function of the foot, and stability during gait.

Unloading mechanism in the total contact cast.

BACKGROUND: The effectiveness of total contact casts is postulated to be due to the reduction of plantar pressure. We investigated plantar loads to evaluate the mechanism by which total contact casts off-load the plantar surface of the foot to determine if it is the intimate molding of the weightbearing plantar surface or if a below-knee cast is necessary. METHODS: Plantar pressures and forces in a total contact cast (TCC) were recorded in 12 healthy subjects, using the Pedar (Novel GmbH, Munich, Germany) pedobarographic system. The measurements were repeated after removal of the 'shank' portion of the cast (proximal to malleoli), leaving in effect, a well-molded shoe-cast (SC). Measurements included average force and peak pressure. All parameters were measured under two different loading conditions: single-leg standing balanced on the casted limb and over-ground walking. To assess the contribution of calf geometry, the 'calf ratio' was calculated by dividing the largest by the smallest circumferences of the calf. All parameters were compared between TCC and SC for each subject in each of the two conditions. Paired t-tests were used to evaluate significance, which was set at a level of p < 0.006 due to the Bonferroni Correction. RESULTS: Removal of the shank portion of the TCC significantly increased the average plantar force by 31% during walking. The force only increased 9% during standing, which was not significant. Peak pressure increased 53% after removal of the shank portion of the TCC during walking. Peak pressure was not significantly different during standing on one limb. No correlation was found between the calf ratio and the magnitude of change in the measured values. CONCLUSIONS: These results help to partially explain the widely recognized clinical observation that molded insoles and shoes, no matter how well conformed to the foot, do not reduce plantar loads as effectively as a total contact cast. The mechanism appears to be a critical unloading function of the proximal, 'shank' portion of the cast, presumably due to reduction in ankle motion.

Knee bracing for unicompartmental osteoarthritis.

Unicompartmental osteoarthritis of the knee affects millions of individuals. Most nonsurgical management of this progressive disease is primarily directed at reducing inflammation and pain with medication. Evidence supports the clinical efficacy of bracing for managing osteoarthritis of the knee. In some patients, bracing significantly reduces pain, increases function, and reduces excessive loading to the damaged compartment. A variety of health and functional status instruments, as well as radiologic techniques and biomechanical investigations, has been used to evaluate the unloading capabilities of these braces. Although changes in angulation are relatively minimal, the braces have been shown to load share and thus reduce the stresses in the degenerated medial compartment of the knee.

Functional outcome of arthrodesis of the first metatarsophalangeal joint using parallel screw fixation.

BACKGROUND: Arthrodesis of the first metatarsophalangeal (MTP) joint is a reliable procedure for a painful hallux. Most studies focus on the surgical results rather than the functional outcome for the patient. Therefore, we examined the effects of first MTP joint arthrodesis on activities of daily living and recreational activities. METHODS: Fifty-three patients (60 feet) who had isolated arthrodesis of the first (MTP) joint using a parallel screw fixation technique were evaluated for the functional outcome after the surgery to determine the effect of the arthrodesis on the activities of daily living and on recreational sports and exercise. RESULTS: Fusion was achieved in all patients; all but three stated that they would have the surgery again. Postoperative pain scores evaluated using the Visual Analogue Scale indicated effective pain relief. High levels of function were demonstrated in this group of patients. CONCLUSION: Arthrodesis of the first MTP joint is not only a successful surgical technique for relief of pain and correction of deformity but also allows a high level of function in everyday life and in recreational activities.

Sutureless avascular meniscal repair with a photoactive naphthalimide compound: a preliminary animal study.

PURPOSE: The purpose of this study was to evaluate the ability of 2 new photoactive naphthalimide compounds to repair a lesion in the avascular zone of the meniscus. TYPE OF STUDY: In vivo animal study. METHODS: Ten Barbados sheep were used as the animal model. Under anesthesia, the left knee joint was opened and 2 identical lesions were produced in the avascular zone of the medial meniscus. The posterior horn lesion was left alone and used as the control and the lesion in the anterior horn was repaired using the photoactive laser technique. The photoactive laser technique involved placing small amounts of a naphthalimide compound into the lesion and then irradiating the site with a laser (457 nm and 1.8 W/cm2) for 6 minutes. Two different versions of the naphthalimide compound were produced and divided between the 10 animals. The joint was then flushed with normal saline and closed in layers with resorbable sutures. Four animals were euthanized at the end of 1 month and 6 animals were euthanized at the end of 3 months. After death, the medial meniscus was exposed, dissected free, and then placed in 10% buffered formalin for histologic preparation and staining. RESULTS: At 1 month, the control lesions grossly showed no repair and the photochemically repaired lesions appeared to be bonded. The photochemically repaired lesions showed some bridging by an eosinophilic amorphous-appearing substance. The previous cleft within the fibrocartilaginous structure had disappeared, and early formation of connective tissue fibers was identified. However, some reduction in cellularity was seen in these tissue sections. At 3 months, again the control lesions did not show any repair response, while the photochemically repaired lesions showed results similar to the animals at 1 month, but with a less consistent pattern of tissue bonding and remodeling. The reduced tissue cellularity was still noted. There was no discernible difference between the naphthalimide compounds. CONCLUSIONS: These preliminary results demonstrate the potential usefulness of this photochemical bonding for the treatment of avascular meniscal lesions. Additional research will be necessary to fully understand the mechanism of this repair and optimize its use before any human trials. CLINICAL RELEVANCE: This is a preliminary animal study investigating the short-term in vivo effects of a novel photochemical compound for the repair of meniscal lesions. This repair may someday be valuable in the repair of avascular meniscal lesions.

Photochemical tissue bonding using monomeric 4-amino-1,8-naphthalimides.

Certain substituted naphthalimides have been shown to produce, on photochemical activation, mechanically viable bonds between a variety of tissue surfaces. It is believed that these compounds act as photochemically activated oxidants, catalyzing the formation of reactive intermediates in the extracellular matrices of approximated tissue surfaces. The condensation of these intermediates results in the formation of crosslinks between the intimate surfaces. Of particular interest is the application of this technique to the repair of tears in the typically unrepairable avascular zone of menisci. The menisci are collagen-rich fibrocartilaginous tissues that support up to 90% of the load across the knee joint and participate in important functions including shock absorption, joint stabilization, hyperextension prevention, and lubrication of the knee. Preliminary ex vivo and in vivo work in our laboratories has demonstrated that photochemically activated naphthalimides have significant potential for the repair of meniscal lesions. We describe preliminary ex vivo studies assessing the relative abilities of a variety of water-soluble monomeric 4-amino-1,8-naphthalimides to bond bovine knee meniscal tissue on visible light irradiation.

The effect of ankle position on plantar pressure in a short leg walking boot.

Short leg walking boots have been shown to be an effective alternative to total contact casting for the reduction of plantar pressure. Conventional theory indicates that placing the ankle in different positions may affect the plantar pressure and ultimately the healing time for a plantar ulcer. This study attempted to determine the changes in plantar pressures due to alterations in the position of the ankle angle in a walking boot. Thirteen healthy subjects were recruited and tested with an insole pressure measurement system. The result demonstrated that small changes in ankle position in dorsiflexion or plantarflexion have a significant impact on resulting forefoot and hindfoot plantar pressures while walking in a prefabricated boot.

Plantar pressures in fiberglass total contact casts vs. a new diabetic walking boot.

The objective of this study was to determine in healthy individuals whether the Bledsoe Diabetic Conformer Boot reduces plantar pressures as well as a fiberglass total contact cast. Eighteen normal subjects, without any prior foot or ankle problems, were recruited for this study. Plantar pressures were measured using the Novel Pedar in-shoe pressure measurement system. The results of this study demonstrate that in individuals without foot deformities, the Bledsoe Diabetic Conformer Boot performs as well as, and in many parameters, even better than a fiberglass total contact cast with respect to reducing the forces and pressures on the plantar surface of the foot.

First metatarsophalangeal arthrodesis: a clinical, pedobarographic and gait analysis study.

This study investigated the results of first metatarsophalangeal (MTP) arthrodesis in terms of clinical outcome measures, plantar pressure distribution, and gait patterns. Ten feet in nine patients with severe hallux rigidus (HR) who underwent first MTP arthrodesis were studied. The preoperative evaluation included a subjective questionnaire, physical exam, AOFAS hallux score, radiographs and dynamic pedobarography (EMED). At follow-up (average 34 months) these were repeated, and gait analysis studies were obtained. Patients showed significant clinical improvement based on the subjective criteria. The mean AOFAS score improved from 38 preoperatively to 90 postoperatively. Postoperative EMED analysis showed restoration of the weightbearing function of the first ray, with greater maximum force carried by the distal hallux at toe-off. Kinematic and kinetic gait analysis from each patient's operative limb were compared to the unaffected contralateral limb and to age- and sex-matched healthy subjects. The kinematic data indicated a significantly shorter step length with some loss in ankle plantar flexion at toe-off on the fused side. The kinetic data indicated a reduction in both ankle torque and ankle power at push-off. Clinical results indicated effective pain relief and a high level of patient satisfaction, consistent with previous reports in patients with symptomatic Hallux Rigidus.

Reduction of medial compartment loads with valgus bracing of the osteoarthritic knee.

BACKGROUND: Patients with medial compartment osteoarthritis of the knee may be treated nonoperatively with adjustable valgus bracing. HYPOTHESIS: Valgus bracing reduces load on the medial compartment through the application of an external valgus moment about the knee, resulting in pain relief. STUDY DESIGN: Prospective cohort study. METHODS: Eleven patients were tested using an instrumented brace and three-dimensional gait analysis. We measured the valgus moment applied by the adjustable valgus brace and determined the compressive load in the medial compartment. We also documented the effects of increased valgus alignment of the brace and increased strap tension on load sharing. Pain and activity levels were also recorded. RESULTS: Pain and activity level improved in all subjects with valgus bracing. During gait, valgus bracing reduced the net varus moment about the knee by an average of 13% (7.1 N.m) and the medial compartment load at the knee by an average of 11% (114 N) in the calibrated 4 degrees valgus brace setting. Increasing valgus alignment with the adjustable brace had a greater effect on the medial compartment load than did increasing strap tension. CONCLUSION: Adjustable valgus bracing was effective in reducing medial compartment load and subsequent pain while also improving knee function in a group of patients with osteoarthritis.

Dynamic knee motion in anterior cruciate impairment: a report and case study.

Knee motion has been routinely analyzed using radiographic techniques in a static setting. Over the past decade, techniques of in vivo dynamic knee motion analysis have emerged, which have shed light on normal and pathologic knee motion. Most of these methods are either invasive or restricted to small indoor laboratories. This paper describes a new device that records in vivo dynamic knee motion without the restrictions of current techniques and shows results when this device is used with a patient with an anterior cruciate impairment. We believe that dynamic knee motion studies are critical to a full assessment of the effect of an injury and to subsequent rehabilitation and recovery and that this new device can be a useful diagnostic tool.