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J Knee Surg 2023; 36(10): 1052-1059
DOI: 10.1055/s-0042-1748823
Original Article

Outcomes of Semiknee Replacement in Skeletally Immature Bone Sarcoma Patients

Dasen Li
1   Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, People's Republic of China
,
Tao Ji
1   Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, People's Republic of China
,
Wei Guo
1   Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, People's Republic of China
,
Huayi Qu
1   Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, People's Republic of China
,
Haijie Liang
1   Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, People's Republic of China
,
Yi Yang
1   Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, People's Republic of China
,
Xiaodong Tang
1   Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, People's Republic of China
,
Rongli Yang
1   Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, People's Republic of China
,
Jichuan Wang
1   Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, People's Republic of China
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Abstract

Introduction A semiknee mega endoprosthesis (SKMEP) was used to replace the resected distal femur or proximal tibia in skeletally immature bone sarcoma patients. This study investigated the surgical technique, endoprosthesis survival rate, functional outcome, complications, and approaches to resolve limb-length discrepancy (LLD) following this procedure.

Patients and Methods In total, 15 girls and 16 boys with a mean age of 9.1 years (range, 4–12) and 8.9 years (range, 5–13), respectively, were included in this study. The mean length of the resected distal femur (15 cases) and proximal tibia (16) was 145.0 and 122.8 mm, respectively. Altogether, 19 custom-made SKMEPs and 12 modular units were used to reconstruct the bone and joint defects.

Results The average follow-up was 82.8 months (range, 4–225 months). Five patients died of disease. Seven SKMEPs were revised to total knee endoprosthesis after a mean of 40.3 months. Nineteen patients retained the original SKMEP, and the mean LLD was 4.3 cm (range, 0–10 cm). One case each of Henderson type 1B, type 2A, type 2B, and type 5B failures was observed. Knee subluxation occurred in two cases. Although a slight laxity of the knee was identified on physical examination, the average Musculoskeletal Tumor Society 93(MSTS93) functional score was 84.5% (range, 57–97%). The estimated implant survival was 70.5% at 5 years.

Conclusion This was the largest retrospective study reporting the application of SKMEP in bone sarcoma patients. For selected skeletally immature bone sarcoma patients, SKMEP is an option with satisfactory functional outcomes and survival rates. However, heightening pads or shoes to compensate the LLD were indispensable before subsequent LLD was adjusted by further operation(s).

Keywords

semiknee - endoprosthesis - limb-length discrepancy - sarcoma - skeletally immature patient


Publication History

Received: 26 May 2021

Accepted: 18 March 2022

Article published online:
11 July 2022

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