Transtibial Osseointegration

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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.

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