Long-term Outcome of Total Femur Replacement

Abstract

Introduction: Total femur replacement is an option instead of amputation for extensive bone tumour or after revision surgery with a massive bone loss. Over a long period of time the patients may need revision surgery, and this might affect the functional outcome. We reviewed all consecutive total femur replacements done for primary and revision surgery of primary bone tumours in our centre to evaluate the long-term functional outcome and survival.

Materials and methods: All patients who had total femur resection and reconstruction with modular endoprosthesis replacement in our centre from June 1997 to May 2022 were reviewed. The respondents were surveyed through WhatsApp using google form which was translated into Bahasa Malaysia based on the Musculoskeletal Tumour Society Scoring System (MSTS). The data were presented as descriptive data on the final survival of the limb and prosthesis.

Results: Ten patients underwent total femur replacement. There were eight osteosarcoma, one giant cell tumour and one chondromyxoid fibroma. Three patients with osteosarcoma succumbed to pulmonary metastases; all had good early post-operative functional outcomes without local recurrence. Seven patients were available for long term evaluation of function with a mean follow-up of 17.6 years (ranged 10-25 years). Four patients with total femur replacement had good functional outcomes (60-80%) without revision with 10-25 years follow-up. Three patients experienced acetabulum erosion and chronic pain that required early hip replacements. Two of them were complicated with superior erosions and bone loss and subsequently were managed with massive reconstruction using cemented acetabulum cage reconstruction. The other has diabetes mellitus with chronic infection following revision of distal femur endoprosthesis to total femur replacement and subsequently underwent limited hemipelvectomy after 14 years.

Conclusion: Total femur replacement offers a good long term functional outcome and prosthesis survival and is a favourable option for limb salvage surgery.

Keywords: limb salvage surgery; long-term outcome; total femur replacement.

Fig 1:

Case 6. A 8-year-old girl with diaphyseal osteosarcoma crossing the distal femur physis with bone marrow extension to the trochanter was initially managed with resection of the entire femur with allograft reconstruction. Four years later, the entire construct was converted to total femur endoprosthesis at her age of 12 due to severe acetabulum erosion and pain. The limb length discrepancy was managed by contralateral all physeal epiphysiodesis. She was ambulating pain-free without support with 3cm shortening 12 years following TFR surgery. (a) MRI showed extensive marrow involvement of the entire femur, (b) total femur allograft reconstruction, (c) acetabulum erosion on pelvic radiograph, (d) Operative photo showed acetabulum cartilage erosion, € Total femur endoprosthesis with hip replacement, (f) lower limb scanogram showed total femur replacement with limb shortening of 2cm.

Fig 2:

Case 3. A 16-year-old boy, diagnosed with distal femur osteosarcoma and medullary extension to the trochanteric region. Wide resection and total femur endoprosthesis were done at the age of 16-year-old. The bipolar femoral head had to be converted to cemented liner due to early cartilage erosion. He came eight years later with limb shortening and an unstable hip due to superolateral erosion of the acetabulum. The hip was reconstructed with cemented Gap II anti protrusio cage and constraint cup for the stability of the hip. After ten years of revision, he is now ambulating pain-free and has a stable hip. (a, b) Total femur endoprosthesis with bipolar head showed acetabular erosion. (c, d) Radiograph and CT scan showed polyethylene liner had migrated superiorly with significant bone loss, (e) Cemented anti protrusio cage with constraint cup. (f) Intra-operative photo showed cemented constrained cup with bipolar articulation.

Fig 3:

Case 7. A 23-year-old gentleman presented with a traumatic spiral fracture involving the midshaft of the right femur. Radiograph revealed the presence of an ill-defined osteolytic lesion in the distal metaphysis of the ipsilateral femur associated with cortical destruction with minimal soft tissue opacity at the posterolateral aspect of the region. He was initially treated with an interlocking nail, and the fracture united. However, there was a progression of distal femur lytic lesion, and biopsy confirmed the conventional type of osteosarcoma. He underwent four courses of chemotherapy and responded well. Total femur with distal quadriceps resection was performed to achieve a wide and adequate margin due to contamination from previous surgery. The limb was reconstructed with total femur endoprosthesis and a motorised latissimus dorsi flap. He is now 10 years post-surgery, disease-free, and ambulating without support with a 20° knee extension lag due to quadriceps weakness. (a) Traumatic oblique fracture mid-shaft femur with early lytic and rarefaction of distal femur. (b) the distal femur lytic lesion progressed but the fracture united well. (c) Bone scan showed active lesion occupied the distal femur and no evidence of distant metastases. (d, e, f) resection of the entire femur with anticipated contamination to the soft tissue and endoprosthesis replacement with latissimus dorsi flap.