Pelvic reconstruction using an ice-cream cone prosthesis: correlation between the inserted length of the coned stem and surgical outcome

LUMiC Endoprosthetic Reconstruction of Periacetabular Tumor Defects: A Multicenter Follow-up Study

BACKGROUND

We previously reported promising early results for periacetabular tumor reconstructions using the LUMiC prosthesis. The current study evaluates mid-term complications, revision rates, cumulative incidence of implant revision, and risk factors for complications in a multicenter cohort.

METHODS

We assessed patients in whom a tumor defect after type P1b+2, P2, P2+3, or P1b+2+3 internal hemipelvectomy was reconstructed with a LUMiC prosthesis during the period of 2008 to 2022. Complications were reported according to the Henderson classification. Competing risks models were used to estimate the cumulative incidence of implant revision for mechanical and nonmechanical reasons, and reoperations for any complication. Cox models were used to study the effect of risk factors on dislocation and infection.

RESULTS

One hundred and sixty-six patients (median follow-up, 4.2 years [interquartile range, 2.6 to 7.6 years]) were included. A total of 114 (69%) were treated for a primary malignant tumor, 46 (28%) for metastatic carcinoma, 5 (3%) for a benign aggressive lesion, and 1 (1%) for another reason. One hundred and sixty-five reoperations were performed in 82 (49%) of the patients; 104 (63%) of the reoperations were within 6 months. Thirty-two (19%) of 166 implants were revised: 13 (8%) for mechanical reasons, mainly dislocation (n = 5, 3%), and 19 (11%) for nonmechanical reasons, mainly periprosthetic joint infection (PJI) (n = 15, 9%). The cumulative incidences of revision for mechanical reasons and PJI (Henderson 1 to 4) at 2, 5, and 10 years were 11% (95% confidence interval [CI], 7% to 17%), 18% (12% to 25%), and 24% (16% to 33%), respectively. Previous surgery at the same site was associated with an increased dislocation risk (cause-specific hazard ratio [HRCS], 3.0 [95% CI, 1.5 to 6.4]; p < 0.01), and resections involving the P3 region were associated with an increased infection risk (HRCS, 2.5 [95% CI, 1.4 to 4.7]; p < 0.01).

CONCLUSIONS

Despite a substantial reoperation risk, the LUMiC prosthesis demonstrated its durability in the mid-term, with a low mechanical revision rate and most patients retaining their primary implant. Most complications occur in the first postoperative months. Patients with previous surgery at the same site had an increased dislocation risk and might benefit from more conservative rehabilitation and aftercare. Measures should be aimed at reducing the PJI risk, especially in resections involving the P3 region.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Hip Transposition Can Provide Early Walking Function After Periacetabular Tumor Resection: A Multicenter Study

BACKGROUND

Reconstruction after periacetabular bone tumor resection involves important tradeoffs; large bone grafts or endoprostheses are reported to offer fair walking function in general but can be technically demanding and carry a high risk of severe complications. Conversely, hip transposition avoids implant-related risks, but stability and functional return may be less consistent. Fewer studies are available on hip transposition, which is also appealing in more resource-constrained environments, and little is known about the time course from surgery to functional return after hip transposition.

QUESTIONS/PURPOSES

(1) What is the time course of recovery of walking function after hip transposition, especially in the first 6 months? (2) What factors are associated with a greater likelihood of early functional recovery? (3) Is early (2-month) functional recovery associated with a greater likelihood of walking ability and higher Musculoskeletal Tumor Society (MSTS) scores?

METHODS

Between 2009 and 2019, six tertiary care centers in Japan treated 48 patients with internal hemipelvectomy for malignant tumors. During that time, the preferred reconstructive approach was hip transposition, and 92% (44 of 48) of our patients were treated with this procedure. Among them, 86% (38 of 44) had follow-up of at least 6 months, had no local recurrence during that time, and were included in our retrospective study. We chose 6 months as the minimum follow-up duration because the endpoints in this study pertained to early recovery rather than reconstructive durability. Hip transposition involved moving the proximal end of the femur (femoral head, resection end of the trochanteric area, and spacers such as prostheses) upward to the underside of the resected ilium or the lateral side of the sacrum if sacroiliac joint resection was performed. The end of the proximal femur was stabilized to the remaining ilium or sacrum using polyethylene tape, polyethylene terephthalate mesh, an iliotibial tract graft, or an external fixator, according to the surgeon's preference. The median age at surgery was 46 years (range 9 to 76 years), there were 23 women and 15 men, and the median follow-up duration was 17 months (range 6 to 110 months). The postoperative time course of functional recovery was assessed with a record review, the timing of functional milestones was identified (wheelchair, walker, bilateral crutches, single crutch or cane, and walking without an aid), and the MSTS score at the final follow-up was assessed. Additionally, demographic and surgical factors were reviewed, and their association with short-term functional recovery and the final functional outcome was analyzed.

RESULTS

Patients started using a walker at median postoperative day (POD) 20 (IQR 14 to 36) and with bilateral crutches at median POD 35 (IQR 20 to 57). At POD 60, which was the approximate median date of discharge, 76% (29 of 38) of patients were able to walk using bilateral crutches (the early recovery group) and 24% (nine of 38) of patients were not able to do so (the delayed recovery group). No baseline factors were different between the two groups. The early recovery group had a higher median MSTS score than the delayed recovery group: 57% (range 17% to 90%) versus 45% (13% to 57%) (p = 0.047). Moreover, more patients acquired better function (a single crutch or cane or more) in the early recovery group, with a median of 5 months (95% CI 4 to 11) than did those in the delayed recovery group (median not reached) (p = 0.0006). The HR was 15.2 (95% CI 2.5 to 93). Forty-two percent (16 of 38) underwent additional surgery for wound management.

CONCLUSION

It took patients a fair amount of time to recover walking function after hip transposition, and patients who could not walk on bilateral crutches at POD 60 seemed less likely to regain walking function and were likely to have lower MSTS scores thereafter. Wound-related complications were frequent. This method may be a realistic alternative for younger patients who have the strength for a long rehabilitation period or those who want to minimize prosthesis-related complications. Future studies with more patients are necessary to understand the risk factors associated with delayed recovery.Level of Evidence Level III, therapeutic study.

Pelvic bone sarcomas, prognostic factors, and treatment: A narrative review of the literature

Primary sarcomas of bone are rare malignant mesenchymal tumors. The most common bone sarcomas are osteosarcoma, Ewing's sarcoma, and chondrosarcoma. The prognosis has improved over the years, but bone sarcomas are still life-threatening tumors that need a multidisciplinary approach for diagnosis and treatment. Bone sarcomas arising in the pelvis present a unique challenge to orthopedic oncologists due to the absence of natural anatomical barriers, the close proximity of vital neurovascular structures, and the high mechanical demands placed on any pelvic reconstruction following the excision of the tumor. While radiotherapy has an important role especially in Ewing's sarcoma and chemotherapy for both Ewing's sarcoma and osteosarcoma, surgery remains the main choice of treatment for all three entities. While external hemipelvectomy has remained one option, the main aim of surgery is limb salvage. After complete tumor resection, the bone defect needs to be reconstructed. Possibilities to reconstruct the defect include prosthetic or biological reconstruction. The method of reconstruction is dependent on the location of tumor and the surgery required for its removal. The aim of this article is to give an insight into pelvic bone sarcomas, their oncological and surgical outcomes, and the options for treatment based on the authors' experiences.

The iliac stemmed cup in reconstruction of the acetabular defects secondary to tumor resection: a systematic review of literature

INTRODUCTION

Stemmed acetabular cups are suitable for reconstruction in case of important bone loss. Nevertheless, their use is not so common, because generally judged very invasive and technically difficult to implant. The aim of the present review is to verify the results of their use and to evaluate indications and complications.

MATERIALS AND METHODS

Literature research was performed in the main healthcare databases; indications, surgical technique, related complications, functional results and implant survival were valued and analyzed for every selected paper.

RESULTS

13 studies were selected, for a population of 424 patients and 428 hips. The main indication was reconstruction after tumor removal; the primary non-oncologic indication was revision for aseptic loosening. The most frequent complications were aseptic loosening and implant failure (16.2%), followed by deep infection (11.3%) and dislocation (9.8%). The average MSTS score was 65.9%; while data regarding functional results for degenerative cases are quite fragmented. The 5-years implant survival was 73.6%.

CONCLUSIONS

Data regarding SAC prostheses are quite rare in the literature; no prospective studies with comparisons with other reconstruction techniques are available so their use is mainly based on the experience of single centers. While data for tumors are more consistent and supported by studies, information on revisions of hip prosthesis implanted for degenerative problems is quite scarce. Preliminary results on the SAC prosthesis as a valid alternative both for tumoral and degenerative revision cases are encouraging. Prospective randomized studies are advocated to value results compared to alternative techniques.

Differences in hip musculoskeletal loads between limbs during daily activities in patients with 3D-printed hemipelvic reconstructions following tumor surgery

BACKGROUND

Anatomical custom-made prostheses, thanks to computer-aided design and 3D-printing technology, help improve osseointegration and reduce mechanical complications in bone reconstructions following bone tumors. A recent quantitative analysis of long-term recovery in patients with 3D-printed reconstructions following pelvic tumor surgery showed asymmetries in ground reaction forces between limbs during different motor activities, while standing very good motor performance and quality of life.

RESEARCH QUESTION

We analyzed hip contact forces and muscle forces in that cohort of six patients with an innovative custom-made reconstruction of the hemipelvis, and we tested the hypothesis that asymmetries in ground reaction forces would result in more marked differences in musculoskeletal forces.

METHODS

State-of-the-art musculoskeletal modeling in an optimization-based inverse-dynamics workflow was used to calculate hip contact forces and muscle forces during five motor activities, and the differences between limbs were statistically evaluated across the motor activity cycles and on the force peaks.

RESULTS

The musculoskeletal loads were found to be not symmetric, as hip loads were generally higher in the contralateral limb. We found significant differences in considerable portions of the motor activities cycles except squat, load symmetry indices indicating a load increase (median up to 25%) on the contralateral limb, especially during stair descent and chair rise/sit, and significantly higher values in the contralateral limb at force peaks.

SIGNIFICANCE

We confirmed the hypothesis that residual asymmetries found in ground reaction forces were amplified when hip musculoskeletal loads were investigated, reflecting a shift of the loads toward the intact limb. Despite the general trend of higher loads found in the contralateral hip, this cannot be considered a risk of overloading, as both hips supported loads in a physiological range or lower, indicating a likely optimal recovery.

The Possibilities of Personalized 3D Printed Implants-A Case Series Study

Background and Objectives: Following the most recent software and 3D printing developments, the use of personalized 3D printed orthopedic implants for treatment of complicated surgical cases has gained more popularity. Today, orthopedic problems that cannot be solved with standard implants may be effectively addressed using personalized prostheses. The aim of this study is to present the designing, modeling and production stages of four different personalized 3D printed prostheses and their application in clinical cases of patients who underwent treatment in various anatomical locations with a precisely specified indication for implantation. Materials and Methods: Based on computed tomography scanning, personalized 3D printed prostheses were designed, produced and used in four patients within a period of three to five days after injury or admission. Results: Early term follow-ups demonstrated good to excellent results. Conclusions: Personalized 3D printed prostheses offer an opportunity for a treatment of choice and provide good anatomical and functional results, shortened surgical time, less complications, and high satisfaction in patients with appropriate indications. The method should be considered primarily for patients with large bone defects, or such indicated for resection. Personalized 3D printed prostheses have the potential to become more common and beneficial in the future.

Long-term functional recovery in patients with custom-made 3D-printed anatomical pelvic prostheses following bone tumor excision

BACKGROUND

Anatomical custom-made prostheses make it possible to reconstruct complicated bone defects following excision of bone tumors, thanks to 3D-printed technology. To date, clinical measures have been used to report clinical-functional outcome and provide evidence for the effectiveness of this new surgical approach. However, there are no studies that quantified the achievable recovery during common activities by using instrumental clinical-functional evaluation in these patients.

RESEARCH QUESTION

What is the motor performance, functional outcome and quality of life in patients with custom-made 3D-printed pelvic prostheses following bone tumor?

METHODS

To analyze motor performance, six patients performed motion analysis during five motor activities at follow-up of 32 ± 18 months. Joint angles, ground reaction forces and joint moments of the operated and contralateral limbs were compared. On-off activity of lower-limb muscles were calculated from electromyography and compared to a healthy matched population. To analyze functional outcome and quality of life, differences in measured hip abductor strength between limbs were evaluated, as well as clinical-functional scores (Harris Hip Score, Barthel Index, Musculoskeletal Tumor Society score), and quality of life (SF-36 health survey).

RESULTS

We found only slight differences in joint kinematics when comparing operated and contralateral limb. The activity of gluteal muscles was normal, while hamstrings showed out-of-phase activities. Ground reaction forces and hip moments showed asymmetries between limbs, particularly in more demanding motor activities. We found a mean difference in hip abductor strength of 48 ± 82 N between limbs, good clinical-functional scores, and quality of life scores within normative.

SIGNIFICANCE

Our study showed optimal long-term results in functional recovery, mainly achieved through recovery of the gluteal function, although minor impairments were found, which may be considered for future improvement of this innovative surgery. The effect of a more loaded contralateral limb on internal loads and long-term performance of the implant remains unknown and deserves further investigation.

Extra-articular resection of the hip joint for pelvic sarcomas: Are there any oncological and functional risks compared with intra-articular resection?

BACKGROUND

While extra-articular resection (EAR) of the knee and shoulder joint is associated with poorer clinical outcomes, the oncological and functional risks of EAR of the hip joint are unknown. We aimed to compare these risks between EAR of the hip joint and intra-articular resection (IAR).

METHODS

We conducted a comparative study of 75 patients who underwent en-bloc tumour resection and limb-salvage reconstruction for bone sarcomas of the peri-acetabulum between 1996 and 2016. We divided patients into two groups for analyses; EAR (n = 21) and IAR (n = 54).

RESULTS

There was no statistical difference in oncological outcomes; the 5-year cumulative incidence of disease-specific death was 34% and 35% in the EAR and IAR groups, respectively (p = 0.943), and the 5-year cumulative incidence of LR was 26% and 34%, respectively (p = 0.482). The most common complications were dislocation (28%) and deep infection (28%); there was equally no difference between the groups. The mean Musculoskeletal Tumour Society score was 66% and 65% in the EAR and IAR groups, respectively (p = 0.795), and were significantly lower in patients with deep infection (52% vs. 69%; p = 0.013). In a sub-analysis on the outcomes in patients who underwent PI-uninvolved PII-resection for chondrosarcoma, no major differences in oncologic and functional outcomes were confirmed.

CONCLUSION

Patients undergoing EAR and limb-salvage reconstructions of the hip joint have undistinguishable oncological, clinical and functional outcomes compared to those undergoing IAR and reconstructions. If preoperative imaging suggests articular tumour involvement, there appears to be no detrimental effect of undertaking EAR to optimise local control.

Periacetabular reconstruction following limb-salvage surgery for pelvic sarcomas

Limb-salvage surgery for pelvic sarcomas remains one of the most challenging surgical procedures for musculoskeletal oncologists. In the past several decades, various surgical techniques have been developed for periacetabular reconstruction following pelvic tumor resection. These methods include endoprosthetic reconstruction, allograft or autograft reconstruction, arthrodesis, and hip transposition. Each of these procedures has its own advantages and disadvantages, and there is no consensus or gold standard for periacetabular reconstruction. Consequently, this review provides an overview of the clinical outcomes for each of these reconstructive options following pelvic tumor resections. Overall, high complication rates are associated with the use of massive implants/grafts, and deep infection is generally the most common cause of reconstruction failure. Functional outcomes decline with the occurrence of severe complications. Further efforts to avoid complications using innovative techniques, such as antibiotic-laden devices, computer navigation, custom cutting jigs, and reduced use of implants/grafts, are crucial to improve outcomes, especially in patients at a high risk of complications.