Outcome of type 4 pelvic resection and reconstruction with a high hip center in malignant pelvic tumours: A case series and short-term review

Abstract

Background

Type 4 pelvic resections for malignant pelvic tumours are complex procedures requiring meticulous surgical planning to balance oncological control and preservation of hip joint function. Reconstruction with a high hip centre is one strategy to restore a mobile hip joint after ilium resection.

Methods

This retrospective case series reviews eight patients (5 males, 3 females; mean age 52.5 years, range 36–70) who underwent Type 4 pelvic resection and high hip centre reconstruction at a single institution. Tumour histologies included chondrosarcoma (n = 5), Ewing’s sarcoma (n = 1), malignant hemangiopericytoma (n = 1), and metastatic papillary thyroid carcinoma (n = 1). The mean follow-up duration was 44 months (24–69 months).

Results

The average surgical time was 4 h (range 3.5–6 h) with a mean estimated blood loss of 1500 ml (range 1200–2000 ml). Complications occurred in 50% of cases, including deep wound infection (n = 1), seroma formation (n = 2), and implant failure (n = 1). There were no local recurrences. Oncological outcomes showed that 3 patients died due to disease progression, 1 remains alive with disease, and 4 are disease-free. Functional outcomes were assessed using the MSTS and TESS scoring systems, with mean scores of 63.4% (range 33.3%–80.3%) and 65.7% (range 25%–86.6%), respectively.

Conclusion

Type 4 pelvic resection with high hip centre reconstruction is a viable option for managing select malignant pelvic tumours, offering reasonable short-term oncological control and functional outcomes despite a notable complication rate. Careful patient selection and surgical planning remain essential.

Introduction

Malignant pelvic tumours, particularly sarcomas and metastatic cancers, present significant surgical challenges, especially when they involve the pelvis. Pelvic resections can result in substantial functional impairments, particularly when the acetabulum is affected. Based on the classifications established by Enneking and Dunham, these resections are categorised into four types: Type 1 involves the iliac wing, Type 2 pertains to the periacetabular region, Type 3 covers the pubic rami, and Type 4 encompasses the entire hemipelvis at the sacrum. ¹ Type 4 resections are regarded as the most complex due to the intricate anatomy of the pelvis and the involvement of critical structures such as the iliac vessels, ureters, and pelvic floor muscles, coupled with the necessity for clear oncologic resection margins.^2,3 Such resections may involve hemipelvectomy, including the removal of all of the pelvic bone alongside adjacent soft tissue. Historically, the treatment of pelvic sarcomas with involvement of the entire hemipelvis often led to hindquarter amputation.

Nevertheless, the emergence of limb salvage surgery has established internal hemipelvectomy as the preferred technique. However, no consensus remains on the optimal reconstruction methods for Type 4 pelvic resections. Effective reconstruction following a pelvic resection aims to enhance functional outcomes by preserving or restoring hip joint mechanics, particularly abductor function critical for gait and stability.^4,5 However, in Type 4 resections, the acetabulum and the abductor mechanisms are sacrificed with the tumour to achieve negative resection margins.

We report on eight patients who underwent Type 4 pelvic resections for malignant pelvic sarcomas, followed by prosthetic reconstruction utilising the high hip centre technique. This study aims to provide a short-term review of functional outcomes and complications associated with this surgical approach.

Materials and methods

This retrospective case series includes patients who underwent Type 4 pelvic resections for malignant pelvic tumours at our centre between 2019 and 2022, with a minimum follow-up period of 2 years. Participants were diagnosed with pelvic sarcomas, either as primary tumours or secondary malignancies, that necessitated a type 4 resection of the pelvis. There were a total of 89 patients with pelvic sarcoma who had undergone surgery during the study period. The breakdown is as follows: 27 patients had type 1 resection, 31 had type 2 resection, 14 had type 3 resection, and 8 had type 4 resection. 15 patients underwent Hindquater amputation (External Hemipelvectomy). The patients who underwent Type 1, Type 2, or Type 3 resections were excluded from the study. All surgeries were performed by two experienced orthopaedic surgeons specialising in sarcoma.

Before surgery, each patient underwent plain radiography, local staging via magnetic resonance imaging (MRI), and systemic staging using positron emission tomography (PET) scans. A biopsy was conducted to confirm histopathological diagnoses and to grade the tumours. Surgical interventions were performed following a thorough review of all biomedical imaging results.

We report the clinical outcomes, including postoperative complications, oncological results (local recurrence and metastasis), and functional outcomes. The follow-up period is defined as the time from the surgery date until either patient death or the last review date. Functional outcomes were assessed using the Musculoskeletal Tumour Society Score (MSTS Score) and the Toronto Extremity Salvage Score (TESS) during the most recent outpatient visit or through a telephone interview. Overall survival was calculated from the date of surgery to the last recorded date of patient survival or the date of death. Data analysis was conducted using Microsoft Excel 2021.

Surgical technique

Two senior orthopaedic oncologists performed all resections under general anaesthesia. All patients underwent bowel preparation the day before the scheduled surgery. Prophylactic antibiotics, specifically intravenous Vancomycin and Metronidazole, were administered following the induction of anaesthesia. Patients were positioned in a floppy lateral position on the operating table.

Type 4 pelvic resections involve the excision of the ilium, ischium, and pubis, including the sacroiliac joint posteriorly and the symphysis pubis anteriorly. This procedure can be approached via a utilitarian or a question mark incision. The incision begins at the posterior superior iliac spine and extends to the anterior superior iliac spine, along the iliac crest, with its length determined by the chosen approach. In the utilitarian approach, the incision is extended along the inguinal crease to the symphysis pubis, with an additional limb created from the anterior superior iliac spine (ASIS) down the lateral thigh. In contrast, the question mark approach extends to the mid-inguinal point before curving laterally along the upper thigh.

During the surgery, dissection began with detaching the abdominal muscles from the iliac crest while preserving the iliacus muscle as a cuff around the tumour, exposing the external iliac vessels, femoral vessels, and nerves. Subsequently, the gluteus maximus and tensor fascia lata muscles were detached on the outer table to form a myocutaneous flap while sparing the gluteal vessels that supply these muscles. Dissection continued down to the sacroiliac joint, and an en-bloc resection was performed through both the sacroiliac joint and pubic symphysis, with extensions through the superior and inferior pubic rami in cases where the tumour did not extend medially.

For reconstruction, a high hip centre technique was utilised, employing an antiprotrusio cage (GAP II, Howmedica, Stryker). The lateral surface of the sacrum was prepared using a reamer to create a slight indentation for secure placement of the Antiprotrusio Cage (APC). The GAP II cage was then anchored to the sacrum using long screws (Figure 1). Once securely in place, a constrained cup (Stryker, Howmedica) was cemented into the APC (Figure 2). The proximal femur was osteotomised transversely at the lesser trochanter level, and a proximal femur endoprosthesis was employed to extend the length of the proximal femur, thereby establishing a high hip centre while maintaining limb length (Figure 3). The primary objective was to restore a stable hip joint centre with normal limb length, facilitating early weight bearing post-surgery. Figure 4 shows the postoperative radiographs of some of the patients.

Figure 1.

Shows the APC stabilised to the lateral border of the sacrum. (a) Common Illiac vessels. (b) Gluteal vessels. (c) APC (Gap 2 cage). (d) Femoral head.

Figure 2.

The constrain cup cemented into the gap 2. (a) Femoral nerve. (b) Gluteal vessels. (c) Constrain cup. (d) Femoral head.

Figure 3.

shows the proximal femur endoprosthesis in situ. (a) Femoral nerve. (b) Gluteal vessels. (c) Sciatic nerve. (d) Proximal femur endoprosthesis.

Figure 4.

Radiograph shows examples of high hip centre reconstruction.

Postoperative care

Following surgery, all patients received a comprehensive postoperative care regimen that included a combination of physical therapy and vigilant monitoring for complications such as infection, wound dehiscence, or prosthetic failure. Patients were encouraged to begin early rehabilitation on the first day after the procedure. Initial exercises included quadriceps isometric contractions, patellar mobility exercises, and ankle flexion-extension activities, all initiated on postoperative day one. Hip flexion, abduction, and extension exercises were introduced as recovery progressed. Patients were permitted to bear full weight on their affected limb starting on postoperative day two.

Functional assessments were conducted at follow-up visits, utilising the Musculoskeletal Tumour Society (MSTS) score and the Toronto Extremity Salvage Score (TESS). As part of the treatment protocol for the patient diagnosed with.

Follow up

The follow-up regimen consisted of regular physical examinations and radiological assessments (pelvic and chest radiographs) conducted every 3 months during the first 2 years. Subsequently, the follow-up schedule transitioned to every 6 months for another 3 years and finally annually for another 5 years. This structured approach aimed to monitor recovery, detect any complications early, and assess functional outcomes in the long term.

Results

This case series included eight patients (5 males, 3 females). The mean age at surgery was 52.5 years (range: 36–70 years), and the mean follow-up duration was 44 months (range: 24–69 months).

All patients were diagnosed with malignant tumours, of which five patients were diagnosed with chondrosarcoma, one with Ewing’s sarcoma, one with malignant hemangiopericytoma and one with metastasis from papillary thyroid carcinoma. These tumours primarily involved the iliac wing, acetabulum and some os pubis. Three patients had lung metastasis at the time of diagnosis of the primary tumour (chondrosarcoma, hemangiopericytoma and papillary thyroid cancer) (Table 1).

Table 1.

Shows patient details.

No.	Age	Sex	Diagnosis	Follow-up (Months)	Chemotherapy	Radiotherapy	Local recurrence	MSTS (%)	TESS (%)	Complications	Oncology outcome
1	43	M	Hemangiopericytoma	60			Nil	77.6	81.9		Dead
2	36	M	Ewings	78	Pre and post operative		Nil	80.3	86.6		Disease free
3	44	F	Chondrosarcoma	24			Nil	66.7	44.0	Deep infection	Disease free
4	70	F	Papillary thyroid cancer	42		Postoperative	Nil	70.0	84.4	Seroma	Dead
5	59	M	Chondrosarcoma	47			Nil	62.5	68.8	Seroma	Alive with disease
6	68	M	Chondrosarcoma	31			Nil	50.0	61.1		Dead
7	52	F	Chondrosarcoma	49			Nil	33.3	25	Cage failure with proximal implant migration	Disease free
8	48	M	Chondrosarcoma	35			Nil	66.8	74.2		Disease free

All patients underwent Type 4 pelvic resections, with an average surgical time of 4 h (range: 3.5–6 h). The average estimated blood loss was 1500 ml (range: 1200–2000 ml). The resections involved removal of portions of the sacrum, acetabulum, pelvic ring, and surrounding soft tissues.

The complication rate was 50%, with complications occurring in 4 patients. One patient developed a deep wound infection that was managed successfully via debridement, washout and antibiotics. She was diagnosed with an infection 6 weeks after the surgery when she presented with right hip pain and upper thigh swelling. She had a washout twice, and a simulant embedded with Vancomycin and Gentamycin was inserted in the 2^nd debridement. She also received a total of 3 months of antibiotics (meropenem). Two patients were diagnosed with seromas and treated successfully with ultrasound-guided aspiration and antibiotics. One patient had implant failure with screw breakage with prosthetic loosening of the GAP II cage and proximal migration of the proximal femur endoprosthesis. The construct eventually stabilised after a short migration (Figure 5). She is currently mobilising with a walking frame with a limb length discrepancy of 4 cm. She is treated conservatively as she is pain-free and able to ambulate with support. No other patient had a limb length discrepancy of more than 2 cm.

Figure 5.

Failure of the APC cage with superior migration and stabilisation.

Oncological outcome: three patients passed away due to primary disease progression, one patient remains alive with the disease, and the other four patients are free of disease. No patients were reported to have local recurrence of disease.

The latest functional outcomes at recent follow-up revealed a mean MSTS score of 63.4% (range 33.33%—80.33%) and a mean TESS score of 65.7% (range 25%—86.6%).

Discussion

Type 4 pelvic resections are among the most demanding procedures in orthopaedic oncology. The primary challenge lies not only in achieving a wide oncological margin but also in reconstructing the massive skeletal defect to restore function. Our short-term results demonstrate that reconstruction with a high hip centre is a feasible option, providing acceptable functional outcomes (mean MSTS 63.4%) with no local recurrences in this small cohort, albeit with a significant complication rate (50%).

To contextualise our results, it is imperative to compare them with outcomes from other reconstruction strategies for major pelvic defects, as illustrated by the comparative studies in Table 2. The choice of reconstruction is nuanced, balancing the risks of complications against potential functional gains. Resection arthroplasty (flail hip), as reported by Gupta et al., offers the simplest approach with a low risk of implant-related complications and a respectable mean MSTS score of 67.3% in their large series (n = 24). ⁶ However, this technique is associated with a very high rate of superficial infection (40.6%) and results in significant limb shortening and instability, often requiring permanent bracing. Biologic reconstructions, such as the autogenous graft with pedicle screws used by Sabourin et al., aim to restore bone stock but are fraught with challenges. ⁷ Their small series (n = 4) reported a catastrophic complication profile, including deep infection (33.3%), graft non-union (42.0%), and soft tissue issues, yielding a functional outcome (MSTS 61.1%) similar to ours but with a much higher morbidity. More modern prosthetic solutions have been developed to improve stability. The hemipelvic endoprosthesis combined with a pedicle screw-rod system, as used by Zhang et al. and Wang et al., shows promising functional results (MSTS 63.3% and 84.0%, respectively).^8,9 These systems provide immediate stability but are not without significant risks, including deep infection (5–16.7%), dislocation (10%), and mechanical failure (16.7%). Wang et al.’s series also reported a high rate of delayed wound healing (33.3%). The 3D-printed endoprosthesis reconstruction presented by Zeping et al. offers excellent customisation and a high MSTS score (79.6%), but it still carries a substantial infection risk (35.7%). ¹⁰

Table 2.

Comparison papers on type 4 resections.

Study	No of patients	Type of resection	Reconstruction	Follow-up (Months)	MSTS (%)	Complications
Gupta et al.	24	I + IV	No reconstruction	159.0	67.3	Superficial infection 40.6%, recurrence 3.0%
Sabourin et al.	4	I + IV	Autogenous graft with pedicle screws	57.0	61.1	Deep infection 33.3%, hematomas 25.0%, scar necrosis 33.3%, graft non-union 42.0%
Zhang et al.	6	I + II + III + IV	Hemipelvic endoprosthesis combined with pedicle screw-rod system	36.0	63.3	Deep infection 5.0%, dislocation 10.0%, local recurrence 15.0%
Zeping et al.	10	I + IV	3D printed endoprosthesis reconstruction + patient specific instrument	28.5	79.6	Superficial and deep infection 35.7%
Wang et al.	26	I + IV	Hemiplevic reconstruction system with pedicle-screw rod	84.4	84.0	Delayed wound healing 33.3%, deep infection 16.7%, implant failure 16.7%

Our results with the high hip centre technique—a 50% overall complication rate including one deep infection (12.5%), two seromas (25%), and one mechanical failure (12.5%)—fit within the spectrum of reported outcomes for these major reconstructions. While our overall complication rate is notable, the profile is arguably more favourable than the high rates of non-union and deep infection seen in biologic reconstructions ⁷ and the soft tissue complications reported by others. Our mean MSTS score of 63.4% is comparable to the results of Zhang et al. (63.3%) ⁸ and Sabourin et al. (61.1%), ⁷ though it falls short of the excellent scores reported by Wang et al. (84.0%) ⁹ and Zeping et al. (79.6%). ¹⁰ The paramount oncological goal was achieved, with no local recurrences in our cohort, a success rate comparable to or better than those reported in the comparison studies (0–15%).^11,12 While some authors report acceptable outcomes with no reconstruction,^13,14 these approaches may not be satisfactory for some patients, as they require prolonged postoperative immobility, delayed weight bearing, and a significant limb-length discrepancy.

The limitations of this study include its retrospective design, small sample size, and relatively short follow-up period. Larger, multi-centre studies with longer follow-up are needed to further evaluate the durability of this reconstruction and its long-term functional benefits. Nevertheless, based on our experience and this comparative analysis, the high hip centre reconstruction represents a valuable and competitive technique in the armamentarium for managing these challenging cases, particularly when the goal is to preserve a mobile hip joint with a manageable complication profile.^5,15

Conclusion

Type IV pelvic resections remain a complex surgical challenge due to the extensive nature of the resection and the anatomical proximity to critical neurovascular structures. In this series, the use of endoprosthetic reconstruction with a high hip centre demonstrated promising oncologic and functional outcomes. The reconstruction technique restored pelvic stability, preserved ambulatory function, and allowed most patients to regain independent mobility with manageable complication rates. Our results support the use of this method as a viable reconstructive option following Type IV pelvic resections, particularly when stability and early mobilisation are key objectives.