Custom-made endoprostheses for the femoral amputation stump: an alternative to hip disarticulation in tumour surgery

[Endoprostheses for stump formation after hip disarticulation]

BACKGROUND

Hip disarticulation is a psychologically and physically demanding procedure. However, it remains a therapeutical option whenever limb salvage proves impossible due to sarcoma, severe implant-associated infections or trauma. The stump lengthening procedure (SLP) is a surgical technique that allows partial salvage of the thigh through endoprosthetic proximal femur replacement after hip disarticulation, depending on the amount of viable soft tissue coverage. This leads to a more appealing visual appearance, facilitates prosthetic fitting and significantly improves limb function.

OBJECTIVES

Description of indications for SLP, surgical technique, presentation of clinical and functional outcomes.

METHODS

Review of applying literature and presentation of outcomes of our own SLP collective.

RESULTS

The risk of local recurrence does not increase after SLP compared to hip disarticulation. While the majority of patients can be fitted with an exoprosthesis, a walking aid is usually necessary for ambulation. Exoprostheses are usually worn throughout the entire day, and patients manage distances of a mean of 2000 metres, even if reconstruction lengths are less than 10 cm. Patients aged 50 years or older tend to wear their exoprosthesis for shorter periods of daywear and achieve significantly poorer functional scores. Postoperative complications are common at a rate of 52%. Periprosthetic infection (21%) and soft tissue perforation of the implant with subsequent implant-associated infection (14%) were the most severe complications observed.

CONCLUSIONS

The stump lengthening procedure poses a feasible alternative to classic hip disarticulation in patients with multiple prior operations and/or advanced stages of disease. It leads to satisfactory cosmetic and functional results without jeopardizing local tumor control. Stump perforation presents as the most common complication. Apart from improving the ability to sit down comfortably, both patients treated with a curative and palliative intent manage to ambulate using exoprostheses. With increasing age at the time of operation, walking aids are necessary for ambulation.

Novel intramedullary device for lengthening transfemoral residual limbs

Background

Lower limb loss is a highly disabling medical condition that can severely impact a person’s quality of life. Recovery becomes especially challenging if an amputee has a short residual limb, which can complicate proper prosthetic fitting, causing discomfort, difficulties in suspension, and reduced mobility. Current limb lengthening techniques such as the Ilizarov apparatus and external fixators are cumbersome, uncomfortable, and have high complication rates. In this study, we investigated the effectiveness of a novel limb-lengthening device that uses intramedullary bone lengthening and requires only one percutaneous rod at the end of the limb during the distraction phase. Only the intramedullary nail remains after the distraction phase, and no external components are required during the consolidation phase. We hypothesize that this system would create a much easier experience for the patient.

Methods

The system was first tested in a mock surgical implantation using plastic femur bones. The device was then tested in a series of cadaveric experiments using pelvis-to-knee specimens by a group of surgeons. Surgeons evaluated the surgical insertion technique, soft tissue considerations, hardware fixation strategies, and the effectiveness of the distraction mechanism. Revisions and improvements to the device and surgical procedure were made based on the results from the cadaveric experiments.

Results

A questionnaire was given to two visiting surgeons following the final iteration of the device. The surgeons reported that the system effectively lengthened the limb, was sturdy, and could be installed efficiently. However, there remains a risk of infection and soft tissue imbalances, similar to that introduced by an external fixator device. Suggestions on how to improve the design of the device and mitigate infection through postoperative management and surgical standard of care will be considered for future clinical trials.

Conclusions

The described intramedullary residual limb-lengthening device has evolved from a prototype to a mature model tested in six cadaveric experiments to date. Further mechanical and functional testing is needed to finalize the device before testing in patients.

Stump lengthening procedure with modular endoprostheses - the better alternative to disarticulations of the hip joint?

We report outcomes of 28 patients after stump-lengthening procedures (SLPs) with modular tumor endoprostheses following high-thigh amputation and hip disarticulation over 11years. Mean follow up was 41.3months (range 7.4 to 133.6months). Mean Musculoskeletal Tumour Society Score was 56% (n=11); ten out of eleven patients alive used an exoprosthesis regularly. Complications occurred in 15 patients with infection being most common. In 2 cases, the prostheses had to be explanted. Our data suggest that SLP facilitates post-operative rehabilitation and prosthesis usage. Modular endoprostheses for stump-lengthening allow optimization of remnant soft-tissue envelope, reducing the risk of stump perforation.