Internal Hemipelvectomy and Pelvic Reconstruction

What the operation is. Internal hemipelvectomy is en bloc resection of part or all of the innominate bone with the lower limb preserved. External hemipelvectomy (hindquarter amputation) removes limb and hemipelvis together and is covered in the hindquarter amputation topic. The choice between them hinges on neurovascular involvement and soft-tissue coverage, and the resection is planned by zone, not by tumour size alone.

Who is a candidate. The principal indications:

• Primary bone sarcoma of the pelvis: chondrosarcoma (the most common pelvic primary in adults, chemo- and radio-resistant, so the surgical margin is everything), Ewing sarcoma after neoadjuvant chemotherapy, and osteosarcoma
• Selected soft-tissue sarcomas invading the pelvis
• Carefully selected solitary metastases or locally aggressive benign lesions (giant cell tumour) where curettage is inadequate
• Occasionally infection or a failed prior reconstruction, as a salvage setting

View larger

The margin comes first. Margin quality drives outcome, particularly in chondrosarcoma, where adjuvant therapy will not rescue a contaminated margin. The resection planes are planned on cross-sectional imaging, including whether the sacrum, femoral head or adjacent viscera must be included, and if no wide margin is possible with the limb in situ the operation is an external hemipelvectomy.

What limb salvage requires. All of the following must be satisfied:

• An achievable oncological margin (wide for sarcoma) with the limb retained
• A preservable femoral neurovascular bundle and at least one major nerve to the limb: classically the sciatic. Loss of the femoral nerve alone is compatible with useful function with a knee-stabilising brace
• A soft-tissue envelope adequate for closure, with or without pedicled or free flaps; involve plastic surgery early and map prior incisions and biopsy tracts
• Physiology that tolerates a long, high-blood-loss procedure, judged by anaesthetic and critical care assessment, with cell salvage and major transfusion planning
• A motivated patient who understands the complication rates and the prolonged rehabilitation

When salvage is the wrong answer. A salvaged limb that is insensate, ischaemic and painful is worse than a well-rehabilitated amputation, and marginal physiology or an unmotivated patient shifts the balance towards amputation. When the limb is taken, posterior or anterior flap coverage is planned according to which vessels remain uninvolved, and prosthetic and wheelchair rehabilitation is planned from the outset.

Consent for both. The final decision may be intraoperative, once the resection planes and nerves are directly inspected, so the patient is consented for both internal and external hemipelvectomy preoperatively and the patient, family and rehabilitation team are briefed on either outcome. Rehabilitation, surveillance imaging and psychological support are arranged in advance; nobody wakes to an unexpected amputation.

The language. The Enneking-Dunham classification (JBJS 1978) is the universal language for pelvic resections, and zone dictates both technical difficulty and reconstruction. Combined resections are common: periacetabular chondrosarcoma frequently requires a zone I plus II resection, with the osteotomy through the ilium and the pubic root, or a zone II plus III resection. Always describe a resection by its zones in the exam.

View larger

View larger

Staging. Local staging is a contrast MRI of the whole pelvis: intraosseous and extraosseous extent, the relationship to the iliac vessels, the sciatic and femoral nerves, the SI joint, the hip joint and the bladder and rectum. It is the study that defines the osteotomy planes. The rest of the staging:

• CT chest for pulmonary staging, because bone sarcomas metastasise to lung
• CT pelvis for cortical detail and matrix mineralisation, and as the dataset for navigation or 3D-printed cutting guides and custom implants
• Whole-body staging with bone scan or FDG-PET according to tumour type; PET is valuable for Ewing response assessment
• Bloods, with alkaline phosphatase and LDH where relevant, and fertility and psychology referral in young patients

Biopsy. An image-guided core needle biopsy at the treating sarcoma centre, along a tract agreed with the resecting surgeon. The tract must lie within the planned incision and be excisable en bloc with the specimen: a transgluteal or posterior biopsy of a periacetabular tumour can contaminate the flaps needed for closure and convert a limb-sparing case into an amputation, and the needle should not cross intermuscular planes or enter the joint. Mark the entry site by tattoo or photograph so that it is excised at resection.

Sequencing. Discuss at the sarcoma MDT before definitive surgery. Osteosarcoma and Ewing sarcoma receive neoadjuvant chemotherapy first; chondrosarcoma proceeds straight to surgery.

Operative planning. Virtual surgical planning on fused CT-MRI defines the osteotomies with a planned margin, commonly 5 to 10 millimetres beyond the MRI-defined tumour plus a soft-tissue cuff, and patient-specific cutting guides or computer navigation reduce intralesional resection rates. The rest of the plan:

• Preoperative angio-CT if a vessel is abutted, a vascular surgeon on standby, and consideration of ureteric stents, which make the ureters palpable, and a urinary catheter
• Bowel preparation and a defunctioning discussion if the rectum is at risk
• Cross-match substantial blood and give tranexamic acid. Cell salvage is available but contested in sarcoma: many avoid it or use leucocyte filtration
• Plastic surgery involvement for the flap coverage plan; the pedicled rectus abdominis is the workhorse
• Consent that, beyond the two operations, covers nerve deficit, infection requiring implant removal, and mortality

Choosing the reconstruction. The options form a ladder from no reconstruction at all to a patient-specific implant. Climb it only as far as bone stock, infection risk, demand and resources allow.

View larger

Infection dominates. Deep infection complicates 20 to 40 percent of pelvic resection-reconstructions, reflecting long operating time, large dead space, proximity to the perineum, irradiated tissue and implant surface colonisation. It is the most common reason endoprosthetic reconstructions fail, and the patient is warned that it may cost the reconstruction.

Preventing and treating it. Minimise operating time, staging the most complex cases; manage dead space meticulously; cover implants with flaps; drain; use extended antibiotic prophylaxis, as many units do, and silver or antibiotic coatings where available. When infection is established, debride early and aggressively. An established endoprosthetic infection usually mandates implant removal, as do recurrent infection, loosening or an exposed implant: conversion to hip transposition or a flail hip, or rarely a secondary external hemipelvectomy for uncontrolled sepsis.

Haemorrhage. The common and external iliac vessels, the superior gluteal artery at the greater sciatic notch and the corona mortis are all at risk. Proximal vascular control of the iliac vessels before the osteotomies is a core safety step; massive haemorrhage is the intraoperative killer.

Wound necrosis and flap failure. Long incisions, irradiated tissue and thin posterior flaps closed under tension. Preserve the perforators, plan pedicled rectus abdominis or gluteal flaps prospectively with plastic surgery, and avoid closure under tension. When a flap fails, debride early and salvage or re-cover it before implant exposure supervenes.

Dislocation and mechanical failure. Endoprosthetic dislocation reflects abductor loss and an altered hip centre, answered with dual-mobility or constrained liners, abduction bracing and careful abductor reattachment. Aseptic loosening, stem fracture and iliac stress fracture occur late, and revision options narrow with each failure, ending at transposition or amputation.

Venous thromboembolism. VTE risk is high after pelvic resection. Extended chemoprophylaxis plus mechanical prophylaxis, continued beyond discharge per unit protocol.

Local recurrence and surveillance. Local recurrence tracks with margin status and is highest after intralesional or marginal resection, so the margins are documented on the resection specimen. Surveillance is serial MRI of the pelvis for the resection bed and CT chest for the lung, the dominant site of metastasis, at intervals per sarcoma guidelines for a minimum of 5 years (10 for chondrosarcoma in many units). A recurrence in the bed goes to early salvage resection or amputation if resectable, lung disease to metastasectomy or systemic therapy referral, and external hemipelvectomy is reserved for uncontrolled sepsis or unsalvageable recurrence.

What to expect. Function depends on nerve preservation and abductor reconstruction. Isolated zone I or III resections often score 80 percent or better on the MSTS; zone II reconstructions cluster around 60 to 70 percent regardless of method, with hip transposition performing comparably to endoprostheses at lower reoperation cost. All zone II patients have some abductor deficiency: expect a Trendelenburg gait and a walking aid in the first year, and counsel accordingly.

View larger

• Global epidemiology: pelvic sarcomas are rare — chondrosarcoma is the most common pelvic primary in adults, Ewing sarcoma in children and adolescents; all should be managed in designated sarcoma centres, a principle enshrined in UK NICE sarcoma service guidance, ESMO-EURACAN clinical practice guidelines and equivalent national sarcoma pathways worldwide
• ESMO-EURACAN bone sarcoma guidelines: biopsy at the treating centre along a resectable tract; neoadjuvant chemotherapy for osteosarcoma and Ewing; surgery-first for conventional chondrosarcoma; structured MDT decision-making
• NICE (UK): referral of suspected bone sarcoma to specialist centres; supports the centralisation model that pelvic resection outcomes depend on (volume-outcome relationship is well recognised for these procedures)
• Registry evidence: national arthroplasty registries (NJR, AOANJRR and others) capture little tumour endoprosthesis data; the meaningful datasets are collaborative sarcoma registries and multicentre implant cohorts (for example the European LUMiC collaboration and ISOLS-affiliated series), which consistently report infection as the leading reconstruction failure
• Practice variation by resource setting: custom 3D-printed implants and navigation concentrate in high-resource centres; hip transposition and resection without reconstruction deliver comparable oncological outcomes and respectable function where implant infrastructure, bone banking or revision capacity are limited — an important equity point: limb salvage does not require a custom implant

• Endoprosthesis versus hip transposition for zone II: no randomised data; endoprostheses restore length and early function but carry infection/dislocation/loosening; transposition avoids implant failure at the cost of shortening. Series-level MSTS scores overlap substantially
• Custom 3D-printed implants: enthusiasm and early series are favourable, but long-term fixation, cost-effectiveness and the inflexibility problem (implant fixed before final margins) remain unresolved
• Navigation and patient-specific guides: reduce intralesional resection rates in comparative series, but survival benefit is unproven
• Cell salvage in sarcoma surgery: theoretical tumour-cell reinfusion risk versus massive transfusion need; leucodepletion filters are used in some centres, avoidance in others
• Reconstruction at all for zone I discontinuity: many patients function well with an unreconstructed defect and modest shortening; when to fuse the ring remains judgement-based
• Thresholds for external hemipelvectomy: with modern flaps and vascular reconstruction, the boundary keeps moving — but survival is driven by tumour biology and margin, not by whether the limb was kept

Related pages. The alternatives at either end: Hemipelvectomy - Hindquarter when the limb cannot be kept, and Hip Disarticulation and Forequarter Amputation for the neighbouring level. Limb Salvage Surgery Principles frames the decision.