Original ResearchA comparison of function after limb salvage with non-invasive expandable or modular prostheses in children
Introduction
Bone sarcomas frequently involve the metadiaphyseal junction and the growth plate of the long bones of children and adolescents. Surgical management of these tumours requires a wide resection with margins that extend into the normal tissue surrounding the tumour [1]. This may necessitate removal of the physis in the skeletally immature child when the tumour abuts or crosses the growth plate [2]. Reconstruction of the knee typically involves placement of a hinged knee type endoprosthesis [3]. In the skeletally immature patient, this creates a limb length inequality as the contralateral extremity continues to grow unabated [4] Custom prosthetic designs were initially unable to address this problem. Many children had to undergo amputation [5] or rotationplasty [6] to avoid future leg length discrepancy and to allow optimum mobility with an external prosthetic limb.
Technological advances to address this problem have resulted in the development of modular oncology prostheses which allow surgeons to periodically replace modular midsections with larger ones to compensate for differences in leg length [7]. This design decreases the necessity for amputation and increases patient satisfaction by preserving the limb and cosmesis. However, the exchange of components requires multiple surgical procedures to be performed over time, and predisposes the patient to significant morbidity [5]. Repeated bouts of tissue damage related to surgery, muscle atrophy related to post-surgical disuse and a general decrease in mobility related to recovery-period immobility may impact optimal limb function and contribute to long-term physical disability and lower quality of life [8].
Among children with remaining growth potential, in an effort to avoid additional surgery, non-invasive expandable prostheses were designed to allow expansion of the prosthesis without an open procedure [9]. The Repiphysis® non-invasive expandable prosthesis is an implant that allows expansion via external activation of a spring mechanism housed in the body of the implant. This device, like the modular systems appropriate for older children with little remaining growth potential, avoids amputation, allows the limb to be lengthened for optimal function and eliminates the potential complications associated with an open surgical procedure. Although it was anticipated that the use of this device would optimise limb function and mobility in these children as they grew and reached final adult height, data about the functional outcomes after using this type of prosthesis versus the modular system prosthesis were not available.
In this study, our aim was to compare range of motion and functional mobility outcomes among patients with bone sarcoma about the knee who underwent limb salvage surgery and insertion of modular system prostheses to those who underwent limb salvage surgery and insertion of non-invasive expandable prostheses.
Section snippets
Participants
Participants included children treated for lower extremity bone sarcoma at St. Jude Children’s Research Hospital. Forty-two children who underwent limb salvage surgery and received neoadjuvant chemotherapy and who returned for a follow-up visit during 18 consecutive months participated in this study. Inclusion criteria were: (1) diagnosis of lower-extremity bone sarcoma (Ewing sarcoma, osteosarcoma) after 1992; (2) limb-sparing surgical procedure at least one year prior to the scheduled visit;
Participants
Table 1 shows the characteristics of all the patients according to their type of prosthesis. There were no differences in the distributions of gender, race, tumour type, site of surgery (femur versus tibia) or time until first revision with respect to type of prosthesis. There was evidence of a significant difference in patient age at the time of surgery (p < 0.001). As expected, patients who received the modular system prosthesis were older than those who received the non-invasive expandable
Discussion
Progress in the oncologic management of children and adolescents with lower limb malignancies has improved their long-term survival. This progress has been accompanied by rapid developments to improve surgical techniques and to design prosthetic implants that not only improve functional outcomes, but also that limit the need for multiple subsequent surgical interventions. Because malignant bone tumours of the lower extremity frequently require resection of the involved physis, which in the
Role of the funding source
The funding source did not play a role in the study design, data collection, data analysis, data interpretation or writing of this manuscript.
Conflict of interest statement
None declared.
Acknowledgements
Authors at St. Jude Children’s Research Hospital received support from a Cancer Center Support Grant, CA 21765, from the National Institutes of Health and the American Lebanese Syrian Associated Charities (ALSAC).
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Limb salvage surgery has a higher complication rate than amputation but is still beneficial for patients younger than 10 years old with osteosarcoma of an extremity
2022, Journal of Pediatric SurgeryCitation Excerpt :also reported soft-tissue failures as the most common complication in extendible prostheses, with an incidence of 43% and 46%, respectively. The reported incidence of aseptic loosening is 8%–46% [34,35,37]. Aseptic loosening is usually a late complication [35], and thus its incidence in the present study was low (2%).
Osteofibrous dysplasia and adamantinoma: A summary of diagnostic challenges and surgical techniques
2021, Surgical OncologyCitation Excerpt :One patient developed a fracture of the expandable prosthetic component and was then revised to a rigid non-expandable prosthesis with no subsequent complications. Children who had their tibia reconstructed did not show any difference in functional outcomes or complication rates with either one of these techniques [66,101]. Compared to non-vascularized grafts, vascularized flaps are beneficial in providing adequate blood supply and soft-tissue mass to span large resection-generated defects [73,77].
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2017, Clinical OncologyCitation Excerpt :Several manufacturers have developed non-invasive EPRs, where lengthening occurs without an incision. One implant used an electromagnetic thermocouple to melt wax inside a ceramic implant allowing a spring to distract the telescopic parts, but produced unacceptably high levels of failure [60–65]. Other implants use an electromagnetic couple to power a small but powerful motor within the implant that distracts it when a current is applied.
Long-term outcomes of non-invasive expandable endoprostheses for primary malignant tumors around the knee in skeletally-immature patients
2022, Archives of Orthopaedic and Trauma Surgery