Clinical Research Directory

Transtibial Osseointegration

Purpose: Aim 1: Quantify soft tissue complications and infections of service members with transtibial amputations treated with OPRA OI and compare them to transfemoral OI service members. Aim 2: Compare the validated domains, such as functional, quality of life and pain scores, from the preoperative baseline to follow-up visits to determine if persons with transtibial amputations treated with OPRA osseointegrated prostheses demonstrate statistically significant and clinically relevant improvements. Aim 3: Compare physical performance measures preoperatively to follow-up visits for persons with transtibial amputations treated with OPRA osseointegrated prostheses to quantify statistically significant and clinically relevant improvements. Aim 4: Quantify the biomechanical loading and bone quality changes that are directly associated with patient reported outcomes for persons with transtibial amputations treated with OPRA osseointegration. Aim 5: Compare outcome measures between persons with traditional socket prostheses (patients as self-controls) and OPRA OI devices as well as a comparison between persons with transtibial OI and transfemoral OI. Subject Population: Male and female military health care beneficiaries age 22 to 65 years old presenting with a Transtibial limb loss. Study Design: This is a 4-year, prospective cohort FDA pivotal study involving off-label use of the OPRA OI implant in persons with transtibial amputation. Procedures: SURGICAL PROCEDURES: Surgery Stage I: The distal part of the tibia is exposed, preferably using existing incisions, to produce an appropriate fasciocutaneous flap. By the use of fluoroscopy and guiding devices the correct position of the fixture in the medullary canal is found. The canal is reamed step by step to a proper diameter to facilitate insertion of the implant. If the bone quality is poor, as determined by the operating surgeon, autologous bone graft from the iliac crest and/or the medullary canal is used. The fixture is then implanted into the intramedullary canal. Careful surgical technique is essential not to damage the tissue and to achieve osseointegration. A central screw, healing cylinder, and healing bolt are inserted. A myodesis is performed, and the wound is closed using suture. The sutures are removed 2-3 weeks postoperatively. When the skin is completely healed the Patient's conventional socket prosthesis could, in some instances, be used. Surgery Stage II (3-5 months after Stage I): The tibia is exposed via the incision from the Stage I-Surgery. The healing cylinder is removed and the tissues are trimmed in a way that the distal end of the bone protrudes a few millimeters. The skin will be attached directly to it. The endosteal canal is reamed to facilitate placement of the abutment. The skin in the abutment area is then trimmed to a diameter equal to the protruding end of the tibia. This is done to remove the subcutaneous fat and facilitate healing of the dermal layer to the distal end of the bone. The subcutaneous tissue is affixed to the periosteum using absorbable suture to prevent skin movement. A 8mm punch biopsy tool is used to create a circular hole in the skin precisely over the residual tibial canal. The remaining portion of the fasciocutaneous flap is sutured into position. A bolster dressing is placed and routine postoperative wound care is performed by daily dressing changes. Sutures are removed 2-3 weeks postoperatively. CLINICAL PROCEDURES A pre-study visit will be conducted up to 6 months prior to Surgery Stage I. Postoperative visits will occur 2-3 weeks after each surgery. Additional follow-up visits will occur 6, 12, 24, 36, 48 and 60 months post-Surgery Stage II. It is standard of care to follow patients postoperatively from time to time to ensure the wound(s) is /are healing, surveil for complications, and ensure rehabilitation is progressing. That said, the sole reason for engaging in the Clinical Follow-Up Procedures is for the purpose of conducting research under this particular protocol. Additional visits may occur including x-rays at the discretion of the clinical investigator in order to monitor the participants medical status/bone healing. RESEARCH PROCEDURES Timepoints: Baseline, Post-Op Stage II, 6 months, 12 months, 24 months, 36 months, 48 months, and 60 months The patients will be assessed before and after the surgery regularly. Both performance and safety data will be recorded on specially designed electronic Case Report Forms (eCRFs). Clinical and radiological assessments are performed preoperatively (in connection with the surgical procedures.

Clinical and Functional Assessment of Patients With Transfemoral Amputation Treated With Osteointegrated Implant

Limb amputation is a traumatic event that significantly reduces the ability to perform daily activities, impairs mobility, and lowers quality of life. In Italy, approximately 4 million people live with disabilities, with 1.2 million having motor disabilities. Among lower limb amputees (around 200,000), most are elderly, with amputations due to diabetic or vascular issues. Other groups include middle-aged adults (often victims of workplace accidents) and young individuals (victims of traffic accidents). Post-amputation rehabilitation mainly involves the use of prostheses, which, however, can cause skin problems due to the socket (the part that anchors the prosthesis to the residual limb). Among patients using a socket, 34-63% develop chronic skin issues and pain. Complications include excessive sweating, sores, abscesses, and irritation. Additionally, daily volume changes in the residual limb and long-term weight fluctuations further complicate the use of conventional prostheses. In the last two decades, research groups, assisted by experienced surgeons, have worked to develop implant solutions that bypass the socket and address these issues. One such solution is osteointegrated prostheses, which use the principle of osteointegration to anchor the prosthesis directly to the bone of the residual limb. A metal stem is surgically inserted into the medullary canal of the residual limb and fixed through bone growth, establishing a direct connection between the amputated limb and the external prosthesis. Osteointegrated prostheses are widely accepted worldwide as a valid alternative to socket prostheses, especially for young and active individuals with transfemoral, transtibial, transhumeral, or transradial amputations not caused by vascular issues. The key benefit of osteointegration is the restoration of load alignment along the anatomical and mechanical axis, improving control of the residual limb during walking, as well as overall functional capacity and quality of life. Other advantages include greater stability, enhanced sitting comfort, a wider range of hip movement, faster attachment and detachment of the prosthesis, and improved body perception. Additionally, the direct contact between the metal stem and the bone generates sensory feedback (osteoperception), allowing the patient to better control the amputated limb by perceiving ground contact through vibrations transmitted to the bone. Osteointegration offers the only viable alternative for prosthetic use in patients with a short residual limb, where conventional socket prostheses would not be suitable.

Anaesthetic Technique for Minor Lower Limb Amputation Surgery (ATLLAS)

Major lower limb amputation is recognised as a significant cause of morbidity and mortality. In the United Kingdom, 30-day in-hospital mortality is up to 8.7%. Minor lower limb amputations, defined as amputation at or below the ankle, are often considered minor procedures, but mortality at one month is 3.5%, similar to that of below knee amputations and 20% at one year. Any amputation is an indicator of poor health and should be considered a pivotal event in a patient's healthcare journey. In England alone, 21,738 minor lower limb amputations were performed between 2017 and 2020, with annual procedures on an increasing trajectory. Recent work has demonstrated striking regional differences in rates of major lower limb amputations in England which the authors ascribed to inequalities in the provision of healthcare. Improving the regional provision of support services for amputees is also part of the current governments NHS Long Term Workforce Plan (https://lordslibrary.parliament.uk/access-to-prosthetics-for-amputees-in-england/). While multiple studies have aimed to assess the impact of anaesthetic technique on outcomes following major lower limb amputation, there is little published data on factors impacting morbidity and mortality following minor lower limb amputation surgery. Evidence from the USA has shown deleterious effect of general anaesthesia (GA) as compared to regional anaesthesia for minor lower limb amputation in patients with peripheral artery disease. Higher rates of post-operative wound disruption, pneumonia, prolonged intubation, and septic shock were demonstrated with general anaesthesia rather than regional anaesthesia. Investigators have performed a single centre retrospective review of 382 patients undergoing minor lower limb amputation for vascular disease in our Trust (UHNM). We found that our patients undergoing these procedures under peripheral nerve block (PNB) techniques were older with higher rates of heart and kidney disease than those receiving a general anaesthetic. Despite this, these patients had reduced complications and length of hospital stay than the fitter patients. The difference seen here became even more pronounced following propensity matching. Investigators demonstrated a clinically significant reduction in the respiratory complication rate of 5.3% and overall complication rate of 12% and a reduction in length of stay of 6 days following use of peripheral nerve blocks rather than general anaesthesia. Investigators also demonstrated a reduction in length of stay of 4 days when DARF Form v4 - July 2023 16 administering peripheral nerve blocks rather than neuraxial anaesthesia (NA). This small and monocentric study suggests that there is value in repeating this process in a larger, national dataset.

Clinical Outcomes With Non-Powered vs. Powered Prosthetic Knees by K2-level Amputees

The goal of this proposed project is to gather community-based data from the K2-level Transfemoral Amputee (TFA) population to aid in evidence-based prescription of powered prosthetic knees (i.e., choosing the right device to maximize the benefit for each patient). The investigators intend to use this trial data along with a concurrent study being conducted within the K3-K4 level population to guide the implementation of effective prescriptions towards those that can benefit most from a given device and limit prescription to those who would not see benefit in order to ensure the most judicious use of Department of Defense (DoD) and Veteran's Affairs healthcare dollars. The findings will also be shared with the research community to help drive the design of future devices by identifying what features and functions are most beneficial to which patient populations when the devices are used outside of the laboratory. In summary, more community-based data on how powered prosthetic knees compare with the current standard in TFA populations is needed to allow for improved clinical decision making and clinical outcomes.