Transkutanes osseointegriertes Prothesensystem (TOPS) als Durchsteckprothese

Objective

Simultaneous implantation of a TOPS (transcutaneous osseointegrated prosthetic system) and THA (total hip arthroplasty) or staged approach.

Indications

Patients with a TOPS who have coxarthrosis. Patients with an existing THA who have required above-knee amputation and need a TOPS. Patients with an existing TOPS who sustain a medial femoral neck fracture and are not stabilizable with osteosynthesis.

Contraindications

Atypical anatomy, osteomyelitis, radiation or chemotherapy to the affected limb in the last 18 months, peripheral occlusive arterial disease with critical ischemia, diabetes mellitus with polyneuropathy, local dermal or systemic infection, immunocompromised state or use of immunosuppressants, cognitive impairment or lack of compliance for the system, other significant physical impairments.

Surgical technique

Individualized preoperative planning based on CT data. Access similar to conventional THA for existing TOPS. Implantation of an artificial acetabulum with a matching inlay. Similar approach for medial femoral neck fractures without reconstructive options. For existing THA and prior above-knee amputation, removal of existing shaft and potentially neck component for modular prosthesis. Subsequent implantation of TOPS stem in conventional manner.

Postoperative management

Additional THA requires appropriate rehabilitation following endoprosthesis guidelines, tailored to the TOPS situation. For simultaneous implantation of TOPS and THA the patients’ load-bearing capacity and mobilization depend on the duration of the implanted stem.

Results

Only 4 patients have been treated at BGU Murnau making statistical analysis not feasible. Three of the 4 patients experienced significant pain relief and improved mobility shortly after surgery. One patient remained as immobile postoperatively as preoperatively due to inability to achieve pain-free full weight-bearing.