Transcutaneous Osseointegrated Prosthesis Systems (TOPS) for Rehabilitation After Lower Limb Loss: Surgical Pearls.

Background: The biology of osseointegration of any intramedullary implant depends on the design, the press-fit anchoring, and the loading history of the endoprosthesis. In particular, the material and surface of the endoprosthetic stem are designed to stimulate on- and in-growth of bone as the prerequisite for stable and long-lasting integration1-8. Relative movement between a metal stem and the bone wall may stimulate the formation of a connective-tissue interface, thereby increasing the risk of peri-implant infections and implant loss9-12. The maximum achievable press-fit (i.e., the force closure between the implant and bone wall) depends on the diameter and length of the residual bone and thus on the amputation level. Beyond this, the skin-penetrating connector creates specific medical and biological challenges, especially the risk of ascending intramedullary infections. On the one hand, bacterial colonization of the skin-penetrating area (i.e., the stoma) with a gram-positive taxon is obligatory and almost impossible to avoid9,10. On the other hand, a direct structural and functional connection between the osseous tissue and the implant, without intervening connective tissue, has been shown to be a key for infection-free osseointegration11,12. Description: We present a 2-step implantation process for the standard Endo-Fix Stem (ESKA Orthopaedic Handels) into the residual femur and describe the osseointegration of the prosthesis13. In addition, we demonstrate the single-step implantation of a custom-made short femoral implant and a custom-made humeral BADAL X implant (OTN Implants) in a patient who experienced a high-voltage injury with the loss of both arms and the left thigh. Apart from the standard preparation procedures (e.g., marking the lines for skin incisions, preparation of the distal part of the residual bone), special attention must be paid when performing the operative steps that are crucial for successful osseointegration and utilization of the prosthesis. These include shortening of the residual bone to the desired length, preparation of the intramedullary cavity for hosting of the prosthetic stem, precise trimming of the soft tissue, and wound closure. Finally, we discuss the similarities and differences between the Endo-Fix Stem and the BADAL X implant in terms of their properties, intramedullary positioning, and the mechanisms leading to successful osseointegration. Alternatives: Socket prostheses for transfemoral or transtibial amputees have been the gold standard for decades. However, such patients face many challenges to recover autonomous mobility, and an estimated 30% of all amputees report unsatisfactory rehabilitation and 10% cannot use a socket prosthesis at all. Rationale: Transcutaneous osseointegrated prosthetic systems especially benefit patients who are unable to tolerate socket suspension systems, such as those with short residual limbs and/or bilateral limb loss. The use of a firmly integrated endoprosthetic stem allows patients and surgeons to avoid many of the limitations associated with conventional socket prostheses, such as the need to continually fit and refit the socket to match an ever-changing stump6,14-19. Discussion between patients who are considering an osseointegrated prosthesis and those who have already received one ("peer patients") has proven to be a powerful tool to prevent unrealistic expectations. Patients with a transhumeral amputation especially benefit from the stable connection between the residual limb and exoprosthesis. Motion of the affected and even the contralateral shoulder is no longer impaired, as straps and belts are dispensable. Furthermore, transmission of myoelectric signals from surrounding muscles to the prosthesis is fundamentally improved. However, comorbidities such as diabetes mellitus or peripheral arterial disease require careful counseling, even if these conditions were not responsible for the loss of the limb. Transcutaneous osseointegrated prosthetic systems for replacement of an upper or lower limb might not be an option in patients who are unable, for any reason, to take adequate care of the stoma. Expected Outcomes: Despite subtle differences between the systems utilized for the intramedullary anchoring of the prosthetic stem, all data indicate that mobility and quality of life significantly increase while the frequency of stoma infections is remarkably low as long as the patient is able to follow simple postoperative care protocols2-5,9,10,13-19. Important Tips: The impaction pressure of the implant depends on the diameter of the implant and the quality of the residual bone (i.e., the time interval between the amputation and the implantation of the prosthetic stem). The extent of reaming of the inner cortex of the residual bone must be adapted to these conditions. The standard Endo-Fix Stem and BADAL X implant are both slightly curved to adapt to the physiological shape of the femur. Thus, the surgeon must be sure to insert the implant in the right position and at the correct rotational alignment. When preparing a short femoral stump, carefully identify the exact transection level in order to obtain enough bone stock to anchor the implant in the correct intramedullary position for an additional locking screw into the femoral neck and head. Depending on the residual length of the humerus and the press-fit stability of the implant, the utilization of locking screws is optional, as a notch at the distal end of the implant guarantees primary rotational stability. Acronyms and Abbreviations: TOPS = transcutaneous osseointegrated prosthesis systemsEEP = endo-exo prosthesisMRSA = methicillin-resistant staphylococcus aureusa.p. = anteroposteriorK-wire = Kirschner wireCT = computed tomographyDCA = double conus adapterOFP = osseointegrated femur prosthesis.

[Functional rehabilitation after transfemoral amputation : Shaft prosthesis or endo-exo prosthesis?] / Funktionelle Rehabilitation nach Oberschenkelamputation : Schaftprothese oder Endo-Exo-Prothese?

BACKGROUND: After transfemoral amputation a prosthesis is required to restore autonomous standing and bipedal locomotion. Attachment of the prosthesis can be achieved either classically via socket suspension with a shaft in the stump or directly via implantation of an intramedullary transcutaneous femoral prosthesis (osseointegrated prosthesis). AIM: A fully instrumented gait analysis should enable objectification of the anticipated advantages of the EEP with respect to the gait pattern and individual mobility. MATERIAL AND METHODS: In two patients with a unilateral transfemoral amputation a comprehensive gait analysis was carried out prior to and 6 months (patient 1) or 11 and 20 months (patient 2) after switching from a socket prosthesis to an EEP. This was carried out in the Gait Realtime Analysis Interactive Lab (GRAIL), a fully instrumented gait laboratory with virtual reality and enables assessment close to the conditions of daily life. RESULTS: In both cases the gait analysis confirmed the advantages associated with an EEP for the transmission of force to the prosthesis and the accompanying improvement in gait symmetry.

Fifteen years of experience with Integral-Leg-Prosthesis: Cohort study of artificial limb attachment system.

Integral-Leg-Prosthesis (ILP) is a comparatively new attachment system that allows direct skeletal docking of artificial limbs. Between January 1999 and December 2013, 69 patients with transfemoral amputation were fitted with ILPs by a single German surgeon. Device design iterations and surgical techniques evolved during these years. For the purposes of comparison, patients receiving the first two designs and procedure iterations were placed in group 1 and the patients fitted with the final design were placed in group 2. Infection rate and planned and unplanned surgical interventions were statistically compared using Fisher exact test. Data demonstrated that the high rate of stoma-associated infections seen in group 1 was dramatically reduced in group 2. Of the 39 patients with 42 implants in group 2, none had operative interventions secondary to infection. All group 2 patients remained infection-free without the use of antibiotics by following a simple but defined wound-hygiene protocol. We concluded that the final iteration of the osseointegrated intramedullary device with a low energy surface at the soft tissue and prosthesis interface allowed a biologically stable skin stoma that remained infection-free without chronic use of antibiotics. The reduction in the infection rate was attributed to the clinically based, empirically driven changes in design and surgical techniques.

The Evaluation of Daily Life Activities after Application of an Osseointegrated Prosthesis Fixation in a Bilateral Transfemoral Amputee: A Case Study.

Individuals with a transfemoral amputation (TFA) may experience limitations in daily life due to reduced mobility and prosthesis-related problems. An osseointegrated prosthesis fixation (OPF) procedure in amputees might contribute to a solution for patients with short stumps or socket-related problems. To date, no study has specifically described the application of an OPF procedure in individuals with a TFA. This study evaluated the level of daily life activities of a 21-year old service member with a bilateral TFA and cerebral trauma. Due to a short stump length and coordination problems, an OPF procedure was deemed the most suitable option.The result of this procedure and the rehabilitation program showed an increased mobility and satisfaction as obtained by the assessment of life habits questionnaire (LIFE-H) and lower extremity functional scale. The participant was able to walk short distances and the Genium knee provided a stance position. Stair ambulation is impossible because of inadequate muscle capacity.In this specific case we conclude that the quality of life improved through the use of an OPF. However, OPF might not be the appropriate device for every individual with TFA, due to varying bone compositions, co-morbidities, and limited clinical experience and unknown long-term effects.