Primary Stability of Collared and Collarless Cementless Femoral Stems – A Finite Element Analysis Study

Background: Primary stability of the femoral stem is important for the long-term results of cementless total hip arthroplasty. Cementless collared stems have been known to have higher stability than collarless stems when there is a contact between the collar and the calcar. The purpose of this study was to compare the stabilities of collared stem and collarless stem in 2 loading conditions: 1) flat walking and 2) stair climbing. Methods: We constructed 3 finite element models. In the first model, the collar had contact with the calcar. The second model had a 1 mm gap between the calcar and the collar. The third model was constructed with a collarless stem. The proximal femur around the stem was divided into 3 zones: the upper zone (Gruen zones 1 and 7), the middle zone (Gruen zones 2 and 6), and the lower zone (Gruen zones 3 and 5). The micromotion at the stem/bone interface was measured at each zone of the 3 models under the 2 loading conditions. Results: The results showed that collared stems were more stable when the collar was in contact with the calcar than when a gap was left between the collar and the calcar. In particular, collar contact was highly effective in suppressing the micromotion proximal to the stem. Conclusions: Compared to the collarless stem, the collared stem had comparable stability when there was a gap at the collar and calcar interface and higher stability when there was contact between the collar and the calcar

Musculo-cutaneous flap for reconstruction surgery for deep surgical site infection after total en bloc spondylectomy: A technical note

Background: Total en bloc spondylectomy (TES) is potential radical resection surgery for spinal tumors. Surgical procedure of TES includes extremely wide detachment of surrounding soft tissue from pathological vertebra, resulting in impairment of blood supply. Moreover, massive dead space inevitably is made after vertebral body resection. Therefore deep surgical site infection (SSI) after TES could be intractable. To date, suitable treatment for deep SSI after TES has not been established. Case description: A 72years old man underwent TES of 12th thoracic level via single posterior approach for primary leiomyosarcoma. Postoperative additional irradiation was performed. One year after surgery, late infection around the cage occurred. We removed the cage followed by autologous iliac bone grafting, we treat the wound by open therapy and daily irrigation, followed by negative pressure wound therapy. Four-month later, we performed musculo-cutaneous flap using latissimus dorsi muscle with plastic surgeons. At the follow-up visit one year after flap surgery, no evidence of recurrence of infection was observed. Conclusion: Musculo-cutaneous flap is one of treatment options to fill the dead space and to control deep SSI after TES. Keywords: Total en bloc spondylectomy, Surgical site infection, Fla

Robotic rehabilitation therapy using Hybrid Assistive Limb (HAL) for patients with spinal cord lesions: a narrative review

ABSTRACT: Background: The Hybrid Assistive Limb (HAL) is a rehabilitation device that utilizes the “interactive biofeedback” hypothesis to facilitate the motion of the device according to the user's motion intention and appropriate sensory input evoked by HAL-supported motion. HAL has been studied extensively for its potential to promote walking function in patients with spinal cord lesions, including spinal cord injury. Methods: We performed a narrative review of HAL rehabilitation for spinal cord lesions. Results: Several reports have shown the effectiveness of HAL rehabilitation in the recovery of walking ability in patients with gait disturbance caused by compressive myelopathy. Clinical studies have also demonstrated potential mechanisms of action leading to clinical findings, including normalization of cortical excitability, improvement of muscle synergy, attenuation of difficulties in voluntarily initiating joint movement, and gait coordination changes. Conclusions: However, further investigation with more sophisticated study designs is necessary to prove the true efficacy of HAL walking rehabilitation. HAL remains one of the most promising rehabilitation devices for promoting walking function in patients with spinal cord lesions

A newly developed upper limb single-joint HAL in a patient with elbow flexion reconstruction after traumatic brachial plexus injury: A case report

We report a case in which elbow flexion exercises using the upper limb single-joint Hybrid Assistive Limb (upper limb HAL-SJ) were implemented in a patient 13 months postoperatively following elbow flexion reconstruction with intercostal nerve transfer after a traumatic brachial plexus injury. Treatment using the upper limb HAL-SJ was administered once a week for 10 sessions from 13 to 16 months after surgery. Exercises using the upper limb HAL-SJ supported elbow motion by detecting bioelectric signals through surface electrodes on the biceps and triceps brachii. No adverse events were observed during treatment with the upper limb HAL-SJ. Improvements in elbow flexion strength were observed during treatment. Treatment with the upper limb HAL-SJ can be performed safely and effectively following elbow flexion reconstruction by intercostal nerve transfer after a traumatic brachial plexus injury