What Is the Outcome of Allograft and Intramedullary Free Fibula (Capanna Technique) in Pediatric and Adolescent Patients With Bone Tumors?

The role of the periosteal sleeve in the reconstruction of bone defects using a non-vascularised fibula graft in the pediatric population

BACKGROUND

Following resection of large benign bone tumors surgeons are confronted with bone defects severely affecting the stability of a limb. To restore the mechanical continuity of the bone different treatment methods using bone grafts have been described. In pediatric patients the thick periosteal sleeve is thought to contribute to bone formation.

HYPOTHESIS

An intact periosteal sleeve is crucial in bone remodelling around a non-vascularised fibular graft used to bridge large bone defects.

METHODS

We present a treatment technique applied in 6 cases comprising of subperiosteal tumor resection at the diaphyseal or metaphyseal level of long bones followed by defect bridging with a non-vascularised fibula graft inserted into the periosteal sleeve of the resection zone. Elastic intramedullary nails or plates were used for stabilisation.

RESULTS

Due to the intact periosteum at the resection site bone integration occurred quickly and full remodelling was seen in all but one case. Tumor location in this case was at the metaphyseal level resulting in tumor resection at the growth plate. Although bone healing at the distal resection site was seen after a few weeks proximal consolidation was only partial. Full reconstitution of the fibula in the remaining periosteal sleeve was seen in 5 cases, partial reconstitution in 1 case.

DISCUSSION

In the pediatric patient, the described technique is an effective and reliable treatment method for large benign bone tumors requiring resection. However, great diameter discrepancy of the donor and recipient site and a thin periosteum can be a limiting factor for its application.

LEVEL OF EVIDENCE

Level IV clinical study.

Treatment of critical-sized bone defects: clinical and tissue engineering perspectives

Critical-sized bone defects are defined as those that will not heal spontaneously within a patient's lifetime. Current treatment options include vascularized bone grafts, distraction osteogenesis, and the induced membrane technique. The induced membrane technique is an increasingly utilized method with favorable results including high rates of union. Tissue engineering holds promise in the treatment of large bone defects due to advancement of stem cell biology, novel biomaterials, and 3D bioprinting. In this review, we provide an overview of the current operative treatment strategies of critical-sized bone defects as well as the current state of tissue engineering for such defects.

RECONSTRUCTION OF BONE DEFECTS AFTER TUMOR RESECTION BY AUTOAND ALLOGRAFTS (review of literature)

The problem of replacement of large bone defects resulting from segmental bone resections in patients with bone tumors is still actual in modern orthopedics. Segmental defects cause the main difficulty especially in cases of disturbance of normal biomechanics while the “gold standard” of reconstruction with bone autograft is not always possible. The reason is that the defect can be so extensive that would make it impossible to harvest necessary autobone stock. Therefore, allografts based on demineralized bone with optimal properties for osteoregeneration are used as an alternative for autograft. For certain composite materials it is possible to program the properties of future graft by changing its compound. Literature analysis revealed that the effectiveness of the allograft in combination with additional components is comparable to autograft effectiveness. Mesenchymal stem cells of both bone marrow and adipose tissue can be used as an additional component to improve osteoregeneration. It is noteworthy that the analyzed studies did not reveal the influence of stem cells on the tumor recurrence. Nevertheless, the authors support the need of further researches in this area to confirm gained results. Some authors still prefer traditional methods of bone traction despite obtaining own satisfactory results of defects reconstruction with allografts. Such opinion is based on proven effectiveness of the method, structural stability of construction during treatment period and ability to adjust the process of bone regeneration at any stage. The authors goal was to analyze publications over the recent 5 years with the results of experiments and clinical studies on the replacement of large bone defects after bone tumor resection with autoand allografts. Based on the literature analysis the authors propose a general algorithm for graft selection in replacement of large bone defects after segmental bone resections. 

Bone adaptation of a biologically reconstructed femur after Ewing sarcoma: Long-term morphological and densitometric evolution

Combining bone allografts and vascularized fibular autografts in intercalary reconstructions after resection of bone sarcomas is of particular interest in young patients as it facilitates bone healing and union and helps reduce fractures. However, adverse events related to bone adaptation still occur. Bone adaptation is driven by mechanical loading, but no quantitative biomechanical studies exist that would help surgical planning and rehabilitation. We analyzed the bone adaptation of a successful femoral reconstruction after Ewing sarcoma during 76-month follow-up using a novel methodology that allows CT-based quantification of morphology and density. The results indicated that the vital allograft promoted bone adaptation in the reconstruction. However, an overall negative balance of bone remodeling and a progressive mineral density decrease in the femoral neck might threaten long-term bone safety. These concerns seem related to both surgical technique and mechanical stimuli, where a stiff metal implant may determine load sharing, which negatively affects bone remodeling.

Relationship between bone adaptation and in-vivo mechanical stimulus in biological reconstructions after bone tumor: A biomechanical modeling analysis

BACKGROUND

Biomechanical interpretations of bone adaptation in biological reconstructions following bone tumors would be crucial for orthopedic oncologists, particularly if based on quantitative observations. This would help plan for surgical treatments, rehabilitative programs and communication with the patients. We aimed to analyze the biomechanical adaptation of a femoral reconstruction after Ewing sarcoma according to an increasingly-used surgical technique, and to relate in-progress bone resorption to the mechanical stimulus induced by different motor activities.

METHODS

We created a multiscale musculoskeletal and finite element model from CT scans and motion analysis data at a 76-month follow-up of a patient, to analyze muscle and joint loads, and to compare the mechanical competence of the reconstructed bone with the contralateral limb, in the current real condition and in a possible revision surgery that removed proximal screws.

FINDINGS

Our results showed strategies of muscle coordination that led to differences in joint loads between limbs more marked in more demanding motor activities, and generally larger in the contralateral limb. The operated femur presented a markedly low ratio of physiological strain due to load-sharing with the metal implant, particularly in the lateral aspect. The possible revision surgery would help restore a physiological strain configuration, while the safety of the reconstruction would not be threatened.

INTERPRETATION

We suggest that bone resorption is related to load-sharing and to the internal forces exerted during movement, and the mechanical stimulus should be improved by adopting modifications in the surgical treatment and by promoting physical therapy aimed at specific muscle strengthening.

Management of Bone Sarcoma

Treatment of bone sarcoma requires careful planning and involvement of an experienced multidisciplinary team. Significant advancements in systemic therapy, radiation, and surgery in recent years have contributed to improved functional and survival outcomes for patients with these difficult tumors, and emerging technologies hold promise for further advancement.

Simultaneous reconstruction of the bone and vessels for complex femoral defect

Background

Several methods have been reported for intercalary reconstruction of femoral defects. Of these, free vascularized fibula grafts (FVFG) are preferred because of their durability, bone-healing potential, and tolerance to infection. If the bone tumor invades the femoral vessels, simultaneous vascular reconstruction also becomes necessary and significant technical hurdles make limb salvage difficult.

Case presentation

We present a 10-year-old girl who underwent limb-sparing surgery for a distal femur osteosarcoma. The femoral defect was 15 cm long, and the femoral vessel defect was 10 cm long. The femur was reconstructed with bilateral FVFG, and the femoral vessels were reconstructed with saphenous vein grafts. The grafts survived without vascular compromise, and the affected limb was preserved successfully.

Conclusions

Combined use of bilateral FVFG and autologous vein grafts makes limb-sparing surgery for a large osteosarcoma of the femur possible.

The Discrepancy between Patient and Clinician Reported Function in Extremity Bone Metastases

Background. The Musculoskeletal Tumor Society (MSTS) scoring system measures function and is commonly used but criticized because it was developed to be completed by the clinician and not by the patient. We therefore evaluated if there is a difference between patient and clinician reported function using the MSTS score. Methods. 128 patients with bone metastasis of the lower (n = 100) and upper (n = 28) extremity completed the MSTS score. The MSTS score consists of six domains, scored on a 0 to 5 scale and transformed into an overall score ranging from 0 to 100% with a higher score indicating better function. The MSTS score was also derived from clinicians' reports in the medical record. Results. The median age was 63 years (interquartile range [IQR]: 55–71) and the study included 74 (58%) women. We found that the clinicians' MSTS score (median: 65, IQR: 49–83) overestimated the function as compared to the patient perceived score (median: 57, IQR: 40–70) by 8 points (p < 0.001). Conclusion. Clinician reports overestimate function as compared to the patient perceived score. This is important for acknowledging when informing patients about the expected outcome of treatment and for understanding patients' perceptions.