Background: 

Functional outcomes are commonly reported in studies of patients undergoing limb-salvage surgery for the treatment of musculoskeletal tumors; however, interpretation requires knowledge of the smallest amount of improvement that is important to patients: the minimally important difference (MID). We established the MIDs for the Musculoskeletal Tumor Society Rating Scale-93 (MSTS-93) and Toronto Extremity Salvage Score (TESS) for patients with bone tumors undergoing lower-extremity endoprosthetic reconstruction.

Methods: 

This study was a secondary analysis of the recently completed PARITY (Prophylactic Antibiotic Regimens in Tumor Surgery) study. We used MSTS-93 and TESS data from this trial to calculate (1) the anchor-based MIDs with use of an overall function scale and a receiver operating characteristic curve analysis and (2) the distribution-based MIDs based on one-half of the standard deviation of the change scores from baseline to the 12-month follow-up and one-half the standard deviation of baseline scores.

Results: 

Five hundred and ninety-one patients were available for analysis. The Pearson correlation coefficients for the association between changes in MSTS-93 and TESS scores and changes in the external anchor scores were 0.71 and 0.57, indicating high and moderate correlations. The anchor-based MID was 12 points for the MSTS-93 and 11 points for the TESS. Distribution-based MIDs were larger: 16 to 17 points for the MSTS-93 and 14 points for the TESS.

Conclusions: 

Two methods for determining MIDs for the MSTS-93 and TESS for patients undergoing lower-extremity endoprosthetic reconstruction for musculoskeletal tumors yielded quantitatively different results. We suggest the use of anchor-based MIDs, which are grounded in changes in functional status that are meaningful to patients. These thresholds can facilitate responder analyses and indicate whether significant differences following interventions are clinically important to patients.

Level of Evidence: 

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

中文翻译：

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定义肌肉骨骼肿瘤学功能结果的最小重要差异

背景： 

在针对接受保肢手术治疗肌肉骨骼肿瘤的患者的研究中，经常报告功能结果；然而，解释需要了解对患者重要的最小改善量：最小重要差异（MID）。我们为接受下肢内置假体重建的骨肿瘤患者建立了肌肉骨骼肿瘤协会评定量表-93 (MSTS-93) 和多伦多肢体挽救评分 (TESS) 的 MID。

方法： 

这项研究是对最近完成的 PARITY（肿瘤手术中预防性抗生素治疗方案）研究的二次分析。我们使用来自该试验的 MSTS-93 和 TESS 数据来计算（1）使用整体功能量表和接收者操作特征曲线分析的基于锚的 MID，以及（2）基于二分之一的基于分布的 MID。从基线到 12 个月随访的变化分数的标准差以及基线分数标准差的二分之一。

结果： 

五百九十一名患者可供分析。MSTS-93 和 TESS 评分的变化与外部锚评分的变化之间的关联的 Pearson 相关系数分别为 0.71 和 0.57，表明存在高度相关性和中等相关性。MSTS-93 的基于锚点的 MID 为 12 点，TESS 的基于锚点的 MID 为 11 点。基于分布的 MID 较大：MSTS-93 为 16 至 17 点，TESS 为 14 点。

结论： 

对于接受肌肉骨骼肿瘤下肢内置假体重建的患者，确定 MSTS-93 和 TESS 的 MID 的两种方法产生了数量上不同的结果。我们建议使用基于锚定的 MID，其基于对患者有意义的功能状态变化。这些阈值可以促进应答者分析，并表明干预后的显着差异对患者是否具有临床重要性。

证据级别： 

预后III 级。有关证据级别的完整描述，请参阅作者须知。