Revision Amputation with Press-Fit Osseointegration for Transfemoral Amputees.

Abstract

Press-fit transfemoral osseointegration is the technique of inserting an intramedullary metal implant into the residual femur of an amputee; the implant is passed transcutaneously to attach to a standard prosthesis that includes a knee, tibia, ankle, and foot. This allows the prosthesis to be skeletally anchored, eliminating socket-related problems such as tissue compression that can provoke neurogenic pain, skin abrasion, and fitting problems resulting from residual limb size fluctuation¹. Amputees with osseointegrated prostheses typically wear their prosthesis more and experience better mobility, quality of life, and extremity proprioception compared to those with socket prostheses^2-4.

Description: We demonstrate the fundamentals of a single-stage procedure involving an impacted press-fit porous-coated titanium osseointegration implant. The preoperative evaluation is summarized and the specific surgical steps are described: exposure, osteotomy, canal preparation, implant insertion, (optional) targeted muscle reinnervation, muscle closure, soft-tissue contouring and stoma creation, and abutment insertion.

Alternatives: Amputees who are dissatisfied with their quality of life or mobility when using a socket prosthesis can attempt to modify their socket or activity level or accept their situation. Non-osseointegration surgical options to try to improve socket fit include bone lengthening and/or soft-tissue contouring. An alternative design is a screw-type osseointegration implant¹.

Rationale: Press-fit osseointegration can be provided for amputees having difficulty with socket wear⁵. Press-fit osseointegration usually provides superior mobility and quality of life compared with nonoperative and other operative options for patients expressing dissatisfaction for reasons such as those mentioned above, including poor fit, compromised energy transfer, skin pinching, compression, and abrasions.

Expected outcomes: Review articles describing the clinical outcomes of osseointegration consistently suggest that patients have improved prosthesis wear time, mobility, and quality of life compared with patients with a socket prosthesis^3,4. In a recent study² of 18 femoral and 13 tibial amputees who had osseointegration, Reif et al. showed significant improvements in prosthesis wear time, mobility, and multiple quality-of-life surveys at a mean follow-up of nearly 2 years. The most common postoperative complication for this procedure is low-grade soft-tissue infection, which is usually managed by a short course of oral antibiotics. Much less often, soft-tissue debridement or implant removal may be needed to manage infection. Periprosthetic fractures can nearly always be managed with familiar fracture fixation techniques and implant retention⁶.

Important tips: Template and choose an implant with an optimal diameter that encroaches the inner cortex at the narrowest bone diameter; an implant that is too wide may not fit without causing a large fracture, and an implant that is too narrow may fall out. Do not cement the implant⁷.Ideally, the abutment of the implant should rest against a flat transverse bone end with cortical contact and leave the correct amount of room for the prosthetic knee so that it matches the height of the contralateral knee; avoid inserting an implant too distally or in too wide a metaphyseal flare.Gentle impaction pressure is necessary and small contained distal fractures are acceptable, but avoid causing a propagating fracture. Do not place cerclage cables or loose bone graft at these small fracture sites.Avoid the use of a tourniquet during intramedullary reaming to prevent potential heat-induced osteonecrosis.Nerve surgery such as targeted muscle reinnervation, if indicated, can be performed in the same surgical episode as the osseointegration.The muscles should be closed at the bone-implant interface with use of a tight purse string in order to provide a vascularized tissue barrier against bacterial ingress⁸.The skin surrounding the stoma should have unnecessary fat removed, but not excess removal leading to skin necrosis. The skin fascia should be sutured to the muscle surrounding the stoma to stabilize the peri-stomal skin.Soft-tissue contouring is needed to achieve the optimal soft-tissue tension around the stoma and abutment. Single-stage surgery has a distinct advantage in this regard.

Acronyms and abbreviations: MVA = motor vehicle accidentAP = anteroposteriorCT = computed tomographyTMR = targeted muscle reinnervationQTFA = Questionnaire for Persons with a Transfemoral AmputationEQ-5D = EuroQol 5 DimensionsLD-SRS = Limb Deformity-Scoliosis Research Society (questionnaire)PROMIS = Patient-Reported Outcomes Measurement Information System.