Peter R. Cavanagh

The Biomechanical Function of the Anterolateral Ligament of the Knee

Background: Recent anatomic investigations of the lateral structures of the knee have identified a new ligament, called the anterolateral ligament (ALL). To date, the anterolateral ligament has not been biomechanically tested to determine its function. Hypothesis: The ALL of the knee will resist internal rotation at high angles of flexion but will not resist anterior drawer forces. Study Design: Controlled laboratory study. Methods: Eleven cadaveric knees were subjected to 134 N of anterior drawer at flexion angles between 0° and 90° and separately to 5 N·m of internal rotation at the same flexion angles. The in situ forces of the ALL, anterior cruciate ligament (ACL), and lateral collateral ligament (LCL) were determined by the principle of superposition. Results: The contribution of the ALL during internal rotation increased significantly with increasing flexion, whereas that of the ACL decreased significantly. At knee flexion angles greater than 30°, the contribution of the ALL exceeded that of the ACL. During anterior drawer, the forces in the ALL were significantly less than the forces in the ACL at all flexion angles (P < .001). The forces in the LCL were significantly less than those in either the ACL or the ALL at all flexion angles for both anterior drawer and internal rotation (P < .001). Conclusion: The ALL is an important stabilizer of internal rotation at flexion angles greater than 35°; however, it is minimally loaded during anterior drawer at all flexion angles. The ACL is the primary resister during anterior drawer at all flexion angles and during internal rotation at flexion angles less than 35°. Clinical Relevance: Damage to the ALL of the knee could result in knee instability at high angles of flexion. It is possible that a positive pivot-shift sign may be observed in some patients with an intact ACL but with damage to the ALL. This work may have implications for extra-articular reconstruction in patients with chronic anterolateral instability.

Muscle volume, strength, endurance, and exercise loads during 6-month missions in space.

INTRODUCTIONnDecrements in muscular strength during long-duration missions in space could be mission-critical during construction and exploration activities. The purpose of this study was to quantify changes in muscle volume, strength, and endurance of crewmembers on the International Space Station (ISS) in the context of new measurements of loading during exercise countermeasures.nnnMETHODSnStrength and muscle volumes were measured from four male ISS crewmembers (49.5 +/- 4.7 yr, 179.3 +/- 7.1 cm, 85.2 +/- 10.4 kg) before and after long-duration spaceflight (181 +/- 15 d). Preflight and in-flight measurements of forces between foot and shoe allowed comparisons of loading from 1-g exercise and exercise countermeasures on ISS.nnnRESULTSnMuscle volume change was greater in the calf (-10 to 16%) than the thigh (-4% to -7%), but there was no change in the upper arm (+0.4 to -0.8%). Isometric and isokinetic strength changes at the knee (range -10.4 to -24.1%), ankle (range -4 to -22.3%), and elbow (range -7.5 to -16.7%) were observed. Although there was an overall postflight decline in total work (-14%) during the endurance test, an increase in postflight resistance to fatigue was observed. The peak in-shoe forces during running and cycling on ISS were approximately 46% and 50% lower compared to 1-g values.nnnDISCUSSIONnMuscle volume and strength were decreased in the lower extremities of crewmembers during long-duration spaceflight on ISS despite the use of exercise countermeasures. in-flight countermeasures were insufficient to replicate the daily mechanical loading experienced by the crewmembers before flight. Future exercise protocols need careful assessment both in terms of intensity and duration to maximize the dose of exercise and to increase loads compared to the measured levels.

Off-loading the diabetic foot for ulcer prevention and healing

BACKGROUNDnRetrospective and prospective studies have shown that elevated plantar pressure is a causative factor in the development of many plantar ulcers in diabetic patients and that ulceration is often a precursor of lower extremity amputation. In this article, we review the evidence that relieving areas of elevated plantar pressure (off-loading) can prevent and heal plantar ulceration.nnnRESULTSnThere is no consensus in the literature concerning the role of off-loading through footwear in primary or secondary prevention of ulcers. This is likely due to the wide diversity of intervention and control conditions tested, the lack of information about off-loading efficacy of the footwear used, and the absence of a target pressure threshold for off-loading. Uncomplicated plantar ulcers should heal in 6 to 8 weeks with adequate off-loading. The total contact cast and other nonremovable devices are most effective because they eliminate the problem of nonadherence to recommendations for using a removable device. Conventional or standard therapeutic footwear is not effective in ulcer healing. Recent United States and European surveys show a large discrepancy between guidelines and clinical practice in off-loading diabetic foot ulcers. Many clinics continue to use methods that are known to be ineffective or have not been proven effective, while ignoring methods that have been demonstrated to be efficacious.nnnCONCLUSIONSnA number of strategies are proposed to address this situation, notably the adoption and implementation of recently established international guidelines, which are evidence-based and specific, by professional societies in the United States and Europe. Such an approach would change the often poor current expectations for healing diabetic plantar ulcers.

Cost of treating diabetic foot ulcers in five different countries

Most estimates in the literature for the economic cost of treating a diabetic foot ulcer (DFU) are from industrialized countries. There is also marked heterogeneity between the complexity of cases considered in the different studies. The goal of the present article was to estimate treatment costs and costs to patients in five different countries (Chile, China, India, Tanzania, and the United States) for two hypothetical, but well‐defined, DFUs at the extreme ends of the complexity spectrum. A co‐author, who is a treating physician in the relevant country, was asked to choose treatment plans that represented the typical application of local resources to the DFU. The outcomes were pre‐defined as complete healing in case 1 and trans‐tibial amputation in case 2, but the time course of treatment was determined by each investigator in a manner that would be typical for their clinic. The costs, in local currencies, for each course of treatment were estimated with the assistance of local hospital administrators. Typical reimbursement scenarios in each country were used to estimate the cost burden to the patient, which was then expressed as a percentage of the annual per capita purchasing power parity‐adjusted gross domestic product. There were marked differences in the treatment plans between countries based on the availability of resources and the realities of local conditions. The costs of treatment for case 1 ranged from Int

Predictors of depressive symptoms in persons with diabetic peripheral neuropathy: a longitudinal study.

102 to Int

Plantar pressures in diabetic patients with foot ulcers which have remained healed

3959 in Tanzania and in the United States, respectively. The cost for case 2 ranged from Int

Off-loading the Diabetic Foot for Ulcer Prevention and Healing

3060 to Int

Depression predicts first but not recurrent diabetic foot ulcers

188u2009645 in Tanzania and in the United States, respectively. The cost burden to the patient varied from the equivalent of 6u2009days of average income in the United States for case 1 to 5.7u2009years of average annual income for case 2 in India. Although these findings do not take cost‐effectiveness into account, they highlight the dramatic economic burden of a DFU for patients in some countries. Copyright

Prevention of Recurrent Foot Ulcers With Plantar Pressure–Based In-Shoe Orthoses: The CareFUL Prevention Multicenter Randomized Controlled Trial

Aims/hypothesisThe aim of the study was to determine whether diabetic peripheral neuropathy (DPN) is a risk factor for depressive symptoms and examine the potential mechanisms for this relationship.MethodsThis longitudinal study (9 and 18xa0month follow-up) of 338 DPN patients (mean age 61 years; 71% male; 73% type 2 diabetes) examined the temporal relationships between DPN severity (meanu2009±u2009SD; neuropathy disability score [NDS], 7.4u2009±u20092.2; mean vibration perception threshold, 41.5u2009±u20099.5xa0V), DPN somatic experiences (symptoms and foot ulceration), DPN psychosocial consequences (restrictions in activities of daily living [ADL] and social self-perception) and the Hospital Anxiety and Depression subscale measuring depressive symptoms (HADS-D; mean 4.9u2009±u20093.7).ResultsControlling for baseline HADS-D and demographic/disease variables, NDS at baseline significantly predicted increased HADS-D over 18xa0months. This association was mediated by baseline unsteadiness, which was significantly associated with increased HADS-D. Baseline ADL restrictions significantly predicted increased HADS-D and partly mediated the association between baseline unsteadiness and change in HADS-D. Increased pain, unsteadiness and ADL restrictions from baseline to 9xa0months each significantly predicted increased HADS-D over 18xa0months. Change in social self-perception from baseline to 9xa0months significantly predicted increased HADS-D and partly mediated the relationships of change in unsteadiness and ADL restrictions with change in HADS-D.Conclusions/interpretationThese results confirm that neuropathy is a risk factor for depressive symptoms because it generates pain and unsteadiness. Unsteadiness is the symptom with the strongest association with depression, and is linked to depressive symptoms by perceptions of diminished self-worth as a result of inability to perform social roles.

Foot forces during typical days on the international space station

Aimsu2002 The recurrence of foot ulcers is a significant problem in people with diabetic neuropathy. The purpose of this study was to measure in‐shoe plantar pressures and other characteristics in a group of neuropathic patients with diabetes who had prior foot ulcers which had remained healed.