Correction of leg length discrepancy (LLD) in skeletally mature patients with osteosarcoma was rarely reported and quite challenging. This study aimed to propose a treatment strategy of staged lengthening and reconstruction with a standard static prosthesis to address LLD and restore limb function. It also evaluated the effectiveness of the strategy in terms of leg lengthening, functional outcomes, and complications. The strategy for lengthening included three stages. In stage 1, the previous prosthesis was removed and an external fixator with a temporary rod-cement spacer was placed. In this stage, the external fixator was used to lengthen the limb to the appropriate length. In stage 2, the external fixator was removed and the old rod-cement spacer was replaced with a new one. In stage 3, the rod-cement spacer was removed and the standard static prosthesis was planted. Nine skeletally mature distal femoral osteosarcoma patients with unacceptable LLD were treated in our institution from 2019 to 2021. We performed a chart review on nine patients for the clinical and radiographic assessment of functional outcomes, LLD, and complications. The mean (range) leg lengthening was 7.3 cm (3.6–15.6). The mean (range) LLD of the lower limbs decreased from 7.6 cm (4.1–14.2) before the lengthening to 0.3 cm (− 0.3 to 2.1) at the final follow-up with statistical significance (P = 0.000). The mean (range) Musculoskeletal Tumor Society score improved from 30.3% (16.7%–53.3%) before the lengthening to 96.3% (86.7%–100%) at the final follow-up with statistical significance (P = 0.000). Three patients (33.3%) had a minor complication; none needed additional surgical intervention. In the short term, the current staged lengthening and reconstruction with standard static prosthesis provided satisfactory functional outcomes and LLD correction with few complications. The long-term effects of this method need further exploration.

骨骼成熟骨肉瘤患者下肢长度差异（LLD）的矫正很少有报道，而且相当具有挑战性。本研究旨在提出一种使用标准静态假肢分阶段延长和重建的治疗策略，以解决 LLD 并恢复肢体功能。它还评估了该策略在腿部延长、功能结果和并发症方面的有效性。延长战略包括三个阶段。在第一阶段，移除先前的假体并放置带有临时杆水泥垫片的外固定器。此阶段使用外固定器将肢体延长至合适的长度。在第二阶段，移除外固定器，并用新的替换旧的杆-水泥垫片。在第三阶段，移除杆-骨水泥垫片并植入标准静态假体。 2019 年至 2021 年，九名骨骼成熟、LLD 不可接受的远端股骨骨肉瘤患者在我们的机构接受了治疗。我们对 9 名患者进行了图表审查，以对功能结果、LLD 和并发症进行临床和放射学评估。腿部延长的平均（范围）为 7.3 厘米（3.6-15.6）。下肢平均（范围）LLD从延长前的7.6厘米（4.1-14.2）下降到最终随访时的0.3厘米（−0.3至2.1），具有统计学意义（ P = 0.000）。肌肉骨骼肿瘤协会评分的平均（范围）从延长前的 30.3% (16.7%–53.3%) 提高到最终随访时的 96.3% (86.7%–100%)，具有统计学意义 ( P = 0.000)。三名患者（33.3%）出现轻微并发症；没有人需要额外的手术干预。 在短期内，目前使用标准静态假体的分阶段延长和重建提供了令人满意的功能结果和 LLD 矫正，且并发症很少。这种方法的长期效果还需要进一步探索。