Tendon lengthening after achilles tendon rupture-passive effects on the ankle joint in a cadaveric pilot study simulating weight bearing.

BACKGROUND: In recent years, primary Achilles tendon ruptures have increased due to the aging population's participation in physically demanding activities. These injuries commonly occur during recreational sports and frequently lead to a long-term reduction in activity despite treatment. Non-operative methods of treatment for Achilles tendon ruptures may result in the Achilles healing in a lengthened position compared to the pre-injury state. This study uses a cadaveric model that simulates static weight bearing to explore the effect of a lengthened Achilles tendon on ankle joint load distribution. METHODS: Five lower limb cadaveric specimens were placed on a custom jig, where a 334 N (75 lb) load was applied at the femoral head, and the foot was supported against a plate to simulate static double-leg stance. A pressure mapping sensor was inserted into the ankle joint. A percutaneous triple hemiresection tendo-Achilles lengthening procedure (Hoke procedure) was performed on each specimen to simulate tendon lengthening after conservative treatment. Contact pressure, peak pressure, and center-of-pressure were measured for native and tendon-lengthened conditions. RESULTS: Tendon rupture did not significantly alter average contact pressure, peak contact pressures, or center-of-pressure in the ankle joint compared with native tendon. CONCLUSION: Achilles lengthening does not significantly change contact pressures of the ankle joint in this model . This result suggests that the passive restraint on ankle joint translation imposed by the Achilles tendon is minimal without muscle activation.

Pressure Distribution in the Ankle and Subtalar Joint With Routine and Oversized Foot Orthoses.

BACKGROUND: Foot orthoses are used to treat many disorders that affect the lower limb. These assistive devices have the potential to alter the forces, load distribution, and orientation within various joints in the foot and ankle. This study attempts to quantify the effects of orthoses on the intra-articular force distribution of the ankle and subtalar joint using a cadaveric testing jig to simulate weight bearing. METHODS: Five lower-limb cadaveric specimens were placed on a custom jig, where a 334-N (75-lb) load was applied at the femoral head, and the foot was supported against a plate to simulate double-leg stance. Pressure-mapping sensors were inserted into the ankle and subtalar joint. Mean pressure, peak pressure, contact area, and center of force were measured in both the ankle and subtalar joints for barefoot and 2 medial foot orthosis conditions. The 2 orthosis conditions were performed using (1) a 1.5-cm-height wedge to simulate normal orthoses and (2) a 3-cm-height wedge to simulate oversized orthoses. RESULTS: The contact area experienced in the subtalar joint significantly decreased during 3-cm orthotic posting of the medial arch, but neither orthosis had a significant effect on the spatial mean pressure or peak pressure experienced in either joint. CONCLUSION: The use of an oversized orthosis could lead to a decrease in the contact area and alterations in the distribution of pressure within the subtalar joint. CLINICAL RELEVANCE: The use of inappropriate orthoses could negatively impact the force distribution in the lower limb.

Social Media and Orthopaedics: Opportunities and Challenges.

Social media presents unique opportunities and challenges for practicing orthopaedic surgeons. Social media, such as blogging, Facebook, and Twitter, provides orthopaedic surgeons with a new and innovative way to communicate with patients and colleagues. Social media may be a way for orthopaedic surgeons to enhance communication with patients and healthcare populations; however, orthopaedic surgeons must recognize the limitations of social media and the pitfalls of increased connectedness in patient care.

Lower extremity injuries in snowboarders.

The popularity of skiing and snowboarding has increased tremendously over the past few decades. Whereas skiing has been an established winter sport for some time, snowboarding was created only in the 1960s. The great surge in popularity of snowboarding was sparked by its inclusion in the 1998 Winter Olympics. With increased participation in these winter activities has come a tremendous rise in injuries, despite equipment changes and promotion of safety behavior. Although participants in these sports share many common lower extremity injuries, the unique characteristics of skiing and snowboarding lead to marked differences in injury rates and mechanisms of many specific injuries of knee, foot, and ankle. In this article, we review the literature on the epidemiology of lower extremity injuries associated with snowboarding and the associated mechanisms of injury.

A computer assessment of the effect of hindfoot alignment on mechanical axis deviation.

Lower limb malalignment is a common cause of disability that increases risk of osteoarthritis (OA). Treatment of OA may require an osteotomy or arthroplasty, which mandate accurate evaluation of mechanical loading on the limbs to achieve optimal alignment and minimal implant wear. Surgical planning uses a conventional method of mechanical axis deviation (MADC) measured from the center of the femoral head to the center of the ankle. This method fails to account for hindfoot deformity distal to the ankle. We used a computer model to compare MADC with the ground mechanical axis deviation (MADG), drawn from the center of the hip to the ground reaction point. Average anatomic measurements were analyzed with a range of knee and hindfoot angle variation in single leg stance, double leg stance, toe off and heel strike. MADG was consistently higher than MADC, suggesting a more complete estimate of weight-bearing axis that considers hindfoot deformity.

A review of Charcot neuroarthropathy of the midfoot and hindfoot: what every radiologist needs to know.

Charcot neuroarthropathy (CN) occurs commonly in diabetic patients in the joints of the foot and ankle. Radiologists may be the first to suggest the diagnosis of CN and can facilitate prompt intervention and treatment if they are aware of the radiographic manifestations of CN and the signs of progression of disease. Radiologists should also become aware of the evolving treatment of the disease as focus is shifting toward early surgical intervention and limb salvage rather than amputation. Knowledge of preoperative assessment, the types of surgeries performed, and some of the encountered postoperative complications enable the radiologist to facilitate timely intervention by our surgical colleagues and be a valuable member of the management team.

Electrical impedance myography in the assessment of disuse atrophy.

UNLABELLED: Tarulli AW, Duggal N, Esper GJ, Garmirian LP, Fogerson PM, Lin CH, Rutkove SB. Electrical impedance myography in the assessment of disuse atrophy. OBJECTIVE: To quantify disuse atrophy using electrical impedance myography (EIM), a noninvasive technique that we have used successfully to study neurogenic and myopathic atrophy. DESIGN: We performed EIM of the tibialis anterior of subjects with disuse atrophy secondary to cast immobilization and in their contralateral normal leg. Subjects were studied shortly after cast removal and again several weeks to months after the cast was removed and normal mobility was restored. SETTING: Outpatient neurology and orthopedic practices at a tertiary care medical center. PARTICIPANTS: Otherwise healthy subjects (N=10) with unilateral leg fracture. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Resistance, reactance, and phase measured at 50kHz. RESULTS: The main EIM outcome parameter, phase at 50kHz, was lower in the immobilized leg in 9 of 10 cases. Additionally, when normal mobility was restored, the phase of the casted leg increased relative to its initial measurement in all 10 cases, while it increased inconsistently in the contralateral leg. CONCLUSIONS: EIM may be a powerful tool for the assessment of disuse atrophy.

Bone bruises associated with ACL rupture: correlation with injury mechanism.

BACKGROUND: Different patterns of bone bruising are seen on magnetic resonance imaging in acute anterior cruciate ligament ruptures. These patterns may relate to the mechanism of injury. HYPOTHESIS: There is a correlation between the mechanism of anterior cruciate ligament injury and bone bruise patterns on magnetic resonance imaging. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Data regarding the mechanism of anterior cruciate ligament rupture were collected prospectively on patients who had anterior cruciate ligament reconstructions. Inclusion criteria included a clear history of mechanism, magnetic resonance imaging within 6 weeks of injury, and no previous knee injury. Patients were divided into noncontact and contact mechanism groups. Bone bruise frequency, location, depth, and intensity were analyzed using magnetic resonance imaging and correlated with the mechanism of injury. RESULTS: Two hundred fifty-six patients were identified; 100 met the inclusion criteria, 86 were in the noncontact mechanism group, and 14 were in the contact mechanism group. The proportion of bone bruises in the lateral compartment in both groups was higher (P < .001) than in the medial compartment. Bone bruising was more frequent, deeper, and more intense in the noncontact group, with frequency (P = .019) and intensity (P < .001) scores reaching significance at the lateral tibial plateau. Medial compartment bone bruising was seen more frequently than previously reported, particularly in the noncontact group. CONCLUSION: The noncontact mechanism appears to cause more severe bone bruising in both the medial and lateral compartments.

The flat spot of the proximal ulna: a useful anatomic landmark in total elbow arthroplasty.

The relationship between the flat subcutaneous dorsal surface (flat spot) of the ulna and the anatomic flexion axis of the elbow was investigated in 68 cadaveric ulnae. The flat spot and the guiding ridge of the greater sigmoid notch were digitized with an electromagnetic tracking device. The area of the flat spot, as well as its angle with the plane of the greater sigmoid notch, was calculated. The size of the flat spot was variable but was found to be nearly perpendicular to the plane of the greater sigmoid notch (mean, 89.8 degrees +/- 6.5 degrees ). This indicates that the subcutaneous dorsal surface of the proximal ulna is a useful landmark to assist the surgeon intraoperatively to orient the ulnar component axially in total elbow arthroplasty.