兽研Frontiers in Veterinary Science01frontiersin.org 类型 原创研究 发表于 2026年10月6日 DOI 10.3389/fvets.2026.1934451 开放获取 编辑：Antonio González Cantalapiedra，西班牙圣地亚哥-德孔波斯特拉大学 审稿：Mario García-González，西班牙圣地亚哥-德孔波斯特拉大学；Pedro Figueirinhas Paiva，西班牙拉斯帕尔马斯大学大加那利分校 *通讯作者：Bridget L. Anderson bridget.anderson@bluepearlvet.com 收稿 2026年7月10日 修回 2026年8月31日 接受 2026年9月21日 发表 2026年10月6日 引用格式：Anderson BL, Frederick SW and Popovitch C (2026) Assessment of radiographic healing after tibial plateau leveling osteotomy in young and older dogs using the modified RUST scoring system. Front. Vet. Sci. 13:1934451. doi: 10.3389/fvets.2026.1934451 版权 © 2026 Anderson, Frederick and Popovitch。本文为开放获取文章，依据知识共享署名许可（CC BY）条款分发。允许在其他论坛使用、分发和复制，前提是注明原作者和版权所有者，并按照公认的学术规范引用本期刊的原始发表。不符合上述条款的使用、分发或复制均不被允许。 使用改良RUST评分系统评估年轻犬和老年犬胫骨平台水平化截骨术后影像学愈合情况 Bridget L. Anderson 1 *，Steven W. Frederick 2 和 Catherine Popovitch 1 1 BluePearl宠物医院，美国宾夕法尼亚州莱维敦；2 BluePearl科学部，美国佛罗里达州坦帕 目的：使用改良胫骨骨折影像学愈合评分（mRUST）系统，比较年轻犬（2–5岁）和老年犬（8–12岁）胫骨平台水平化截骨术（TPLO）术后截骨部位的影像学愈合评分，并评估大语言模型辅助判读（LLM）、外科医生和外科住院医师评分之间的一致性。研究设计：回顾性筛选2023年至2025年间在2–5岁或8–12岁接受单侧TPLO治疗、体重20–40 kg的客户所有犬。排除患有内分泌疾病或TPLO手术或恢复过程不典型的犬。将犬分为第1组（2–5岁）和第2组（8–12岁）。术后8周X线片由LLM、一名外科医生和一名外科住院医师分别使用4分制mRUST系统独立评分。采用Wilcoxon秩和检验比较各年龄组间的评分，并使用组内相关系数（ICC）评估评分者间一致性。结果：第1组49只犬；第2组51只犬。第1组平均（SD）年龄为3.82（1.11）岁，第2组平均（SD）年龄为9.24（0.99）岁。在各年龄组之间，LLM（p = 0.352）、外科医生（p = 0.908）或住院医师（p = 0.588）评估的mRUST评分均无差异。LLM、外科医生和住院医师评分之间仅具有一般一致性（ICC = 0.4504，p < 0.001）。结论：在TPLO术后8周评估时，实际年龄与mRUST评分无关。mRUST系统在人类观察者之间表现出中等一致性。LLM评分显示出应用前景；但尚需进一步改进以用于临床。 关键词：年龄，犬，成骨，影像学截骨愈合，胫骨平台水平化截骨术 引言 前十字韧带疾病（CCLD）是犬后肢跛行的常见原因。胫骨平台水平化截骨术（TPLO）已成为前十字韧带断裂的标准手术干预措施（1）。该手术通过降低胫骨平台角度，在步态支撑期中和胫骨前向推力，从而恢复膝关节稳定性（2, 3）。然而，需要注意的是，术后骨愈合是手术成功的关键决定因素，因为它影响恢复时间以及犬恢复完全功能的能力。
Anderson等，10.3389/fvets.2026.1934451，《兽医科学前沿》，02frontiersin.org。人类研究表明，衰老可因骨量和骨质量下降而成为骨折的危险因素（4）。此外，小鼠骨愈合的差异以及较老年动物与年轻组相比出现的软骨细胞分化和成熟延迟，以及血管侵入和骨形成受损（5）。这与先前关于老年人群骨折愈合延迟的报道一致，可能源于间充质干细胞分化能力较低以及血管生成/血管发生受损（4）。尽管人类医学中已发现年龄相关骨愈合差异具有重要意义，但专门比较不同年龄组犬在TPLO手术后影像学骨愈合的研究有限。现有临床文献主要关注临床结局，如疼痛管理、跛行缓解、步态分析、骨关节炎发展、关节角度测量和并发症发生率，而未专门量化基于年龄的骨愈合差异（6, 7）。因此，更好地理解年龄如何影响骨愈合结局对于兽医优化术后护理、制定个体化康复方案以及向宠物主人提供准确预后至关重要。TPLO术后影像学骨愈合评估在术后临床决策中发挥核心作用，包括活动限制建议、康复进展和随访评估时机。尽管影像学的主观判读在临床实践中仍很常见，但客观评分系统已被越来越多地采用以实现评估标准化。多种量表已被用于客观评估影像学骨愈合，包括5分、10分和12分等不同量表（8–10）。每种评分系统都面临独特挑战，目前兽医学中尚未建立用于评估截骨愈合的单一标准化评分系统（11）。改良胫骨骨折影像学愈合评分（mRUST）先前为人类骨科医学开发（12），已被改编用于兽医领域，以根据骨痂存在或持续骨折线来定量评估皮质愈合（8）。本研究目的是使用mRUST评分系统评估TPLO术后实际年龄与影像学截骨愈合之间的关联，旨在确定在标准化术后时间点，仅年龄本身是否是影像学愈合延迟的可靠预测指标。我们的零假设是，接受TPLO的年轻犬（2–5岁）和老年犬（8–12岁）在术后8周时的影像学骨愈合评分无差异。方法。研究设计和病例选择。本回顾性队列研究评估了在美国宾夕法尼亚州费城三家私立转诊医院接受治疗的犬TPLO术后影像学截骨愈合情况。回顾性审查了美国宾夕法尼亚州费城三家私立转诊医院环境的电子病历，以识别2023年1月至2025年1月期间接受单侧TPLO的体重20–40 kg的犬。根据手术时的实际年龄将犬分为两个预先定义的年龄组：第1组包括2–5岁犬，第2组包括8–12岁犬。6–7岁犬被排除，以增加年龄组之间的分离度，用于评估影像学截骨愈合中潜在的年龄相关差异。估计每组至少45只犬可在双侧α为0.05时提供80%把握度，以检测总mRUST评分1.5分的组间差异，假设标准差≤2.5分。纳入标准为：犬接受Slocum描述的常规单侧TPLO，年龄在2–5岁（第1组）或8–12岁（第2组），且在术后前8周体格检查或影像学检查中无任何重大并发症（2, 13）。此外，纳入标准包括完整病历和可用的正交膝关节X线片。排除标准为：手术时年龄超出第1组和第2组预先定义范围；根据血液学和/或血清生化评估有全身性疾病证据；术中或术后发生Cook等（13）定义的重大并发症；缺乏完整病历或术后X线片；同时接受皮质类固醇治疗；或手术时发现并发骨科或神经系统疾病（例如内侧髌骨脱位、神经肌肉疾病或肌腱病）。手术操作。麻醉方案在各病例或参与机构之间未标准化。术前用药、诱导、维持和围手术期镇痛方案由麻醉师根据个体患者因素选择，包括年龄、身体状况、并发内科考量和偏好。因此，年轻犬和老年犬的麻醉方案不同。本研究未将具体麻醉方案作为变量进行评估。所有TPLO手术均由委员会认证的兽医外科医生或美国兽医外科学院住院医师在委员会认证外科医生直接监督下完成。所有犬均进行髌旁微型关节切开术以确认CCL断裂诊断。所有CCL在关节切开时均进行清创。如果手术时存在半月板病变，则进行后内侧半半月板切除术。常规使用摆动径向刀片进行曲线截骨。截骨内固定使用锁定TPLO接骨板，采用两种不同植入物系统（DePuy Synthes Vet，宾夕法尼亚州Paoli，以及Arthrex Vet Systems，佛罗里达州Naples）。每只接受Synthes植入物的犬在截骨远端放置两枚皮质螺钉，其余孔用锁定螺钉填充。每只接受Arthrex植入物的犬在截骨远端放置一枚皮质螺钉，其余孔用锁定螺钉填充。所有截骨均使用每块TPLO接骨板的加压孔进行加压。每只犬在手术时由外科医生酌情使用适当尺寸的植入物。所有螺钉放置后按常规闭合。术后立即以及术后约8周获取胫骨正交X线片，近端包括膝关节、远端包括跗骨。对每张X线片评估植入物位置、尺寸是否合适以及胫骨平台角改变是否充分，以完成病例。犬由外科服务团队负责恢复，并在出院时获得关于术后切口护理、活动限制和用药的指示。本研究中的所有犬出院时均给予抗生素药物（头孢泊肟5–10 mg/kg PO q 24 h x 7–14天或头孢氨苄22 mg/kg PO q 12 h x 7–14天），一种
Anderson等，10.3389/fvets.2026.1934451，《 Frontiers in Veterinary Science》03 frontiersin.org 非甾体抗炎药（卡洛芬 2.2 mg/kg 口服 每12小时一次）、额外镇痛药（加巴喷丁 10 mg/kg 口服 每8小时一次）以及镇静剂（曲唑酮 5 mg/kg 口服 每8小时一次）。加巴喷丁和曲唑酮的给药持续时间在各参与机构之间未标准化，而是根据患者的舒适度、行为、所需的活动限制、临床医生的判断以及主人报告的关切进行个体化调整。同样，药物续方的标准化标准也未建立，根据个体患者需求在临床认为适当时追加处方加巴喷丁或曲唑酮。随访复查通过外科部门在术后2周（通过虚拟复查进行切口评估和步态分析）和术后8周进行体格检查和放射学检查。如果通过虚拟复查发现问题或主人报告了关切，则进行面对面复查以进一步评估。在完成初始2周复查后，向主人提供术后活动指导，包括增加缓慢、受控的牵绳行走至每日10分钟，每周增加5分钟，直至8周面对面复查。镇静剂或镇痛药物可根据请求续方。放射学评估 所有8周随访X光片均由一位小动物外科住院医师（BA）、一位委员会认证的小动物外科医生（CP）和一种LLM评估方法进行收集评估。委员会认证的外科医生仅获得匿名X光片，对患者身份、临床信息、实际年龄和年龄组设盲。外科住院医师负责病例识别、数据收集和X光片收集，因此可以接触患者身份和临床信息；然而，在放射学评分时未参考患者年龄和年龄组。外科医生和外科住院医师独立进行各自的评估，且对彼此的mRUST评分设盲。LLM未获得患者身份、临床信息、实际年龄、年龄组或人类评分者所赋评分。截骨部位愈合采用mRUST评分系统进行评分。在正交放射学投照上独立评估四个皮质：内侧位投照上的头侧和尾侧皮质，以及头尾位投照上的内侧和外侧皮质。根据放射学愈合程度，每个皮质被赋予1至4分的评分：1 = 无骨痂形成，截骨线清晰可见；2 = 骨痂形成，截骨线仍可见；3 = 桥接骨痂，截骨线模糊或消失；4 = 完全皮质重塑，皮质连续性恢复，截骨线不可见。四个皮质的评分相加生成总mRUST评分，范围为4至16分，评分越高代表放射学截骨愈合越好。所有三种评估方法（小动物外科住院医师、委员会认证外科医生和LLM辅助判读）均使用相同的评分标准。所有人工评估的图像均使用单一PACS程序（Keystone Asteris，蒙特利尔，加拿大）进行评估。对于大语言模型辅助评估，术后正交TPLO X光片于2025年6月上传至ChatGPT（OpenAI，旧金山，加利福尼亚州，美国）。评估时通过ChatGPT界面可用的具体底层模型版本未记录。多只犬在同一对话中依次评估。每个病例均提供相同的标准化指令和mRUST评分标准。在评分之前，指示模型审查预定义的mRUST标准，随后根据相应的正交放射学视图对头侧、尾侧、内侧和外侧四个皮质分别赋予1至4分的单独评分（图1）。记录四个皮质评分并相加生成总mRUST评分，范围为4至16分。评估每张X光片使用相同的提示词，已在补充材料1中提供。统计分析 连续数值变量采用Shapiro–Wilk检验评估正态性。参数分布的数值变量以均值±标准差（SD）汇总，有序和非参数分布的数值变量以中位数和四分位距（IQR）汇总。参数分布的数值变量采用Student's t检验比较，非参数分布的数值变量采用Wilcoxon秩和检验比较。分类变量之间的频率分布采用独立性卡方检验比较。各评估方法的总mRUST评分在年龄组之间采用Wilcoxon秩和检验比较。统计显著性设定为α = 0.05。LLM、外科医生和住院医师之间总mRUST评分的一致性采用基于单向随机效应模型的单测量、绝对一致性组内相关系数（ICC）评估，并计算95%置信区间。外科医生与外科住院医师总mRUST评分之间的一致性也采用相同方法单独评估。结果 最初共识别439只犬。87只（19.8%）因失访被排除，130只（29.6%）不符合入组的年龄或体重标准，43只（9.8%）同时接受了双侧TPLO手术，79只（18%）先前已在对侧肢体接受过TPLO。剩余100只犬（22.8%）符合所有纳入标准，其中49只犬分配至第1组，51只犬分配至第2组。第1组包括29只（59.2%）绝育雌性和20只（40.8%）去势雄性，而第2组包括26只（51.0%）绝育雌性、23只（45.1%）去势雄性和2只（3.9%）未去势雄性。混合品种犬在两组中均最常见（第1组51.0%，第2组60.8%），其次是拉布拉多寻回犬、比特犬和金毛寻回犬。手术与随访X光片之间的中位间隔为56天（范围54–65天）。年龄因研究设计而不同；第1组平均（SD）年龄为3.82（1.11）岁，而第2组平均（SD）年龄为9.24（0.99）岁。第1组犬略重于第2组犬（中位体重分别为32.6 [IQR：29.0–34.6] kg和29.9 [IQR：24.0–34.3] kg；p = 0.007）。性别分布在两组之间无显著差异（p = 0.311）。植入物类型在两组之间差异显著：第1组75.5%的犬接受了Arthrex植入物，而第2组为54.9%（p = 0.031）。第2组大多数犬（58.8%）接受了半月板切除术，而第1组为34.7%（p = 0.016）。
Anderson等，10.3389/fvets.2026.1934451，《前沿兽医科学》，04，frontiersin.org。LLM评估、外科医生评估和住院医师评估的mRUST总评分在各年龄组之间无显著差异（分别为p = 0.352、p = 0.908和p = 0.588；表1；图2）。各评估方法和年龄组的mRUST评分中位数、四分位距和范围汇总于表1。LLM评估的mRUST评分、外科医生评估评分和住院医师评估评分显示出中等程度的评估者间一致性[单次测量、绝对一致性（AA）ICC = 0.4504（95% CI：0.3305–0.5664；p < 0.001）]。外科医生评估评分与住院医师评估评分之间的一致性更强[单次测量、AA ICC = 0.7923（95% CI：0.7065–0.8552；p < 0.001）]。讨论：本回顾性队列研究发现，使用mRUST评分系统，接受TPLO的年轻成年犬与老年成年犬在术后8周影像学截骨愈合评分上无统计学显著差异。这些发现提示，在所评估的术后时间点，实际年龄与影像学截骨愈合无关；然而，不能排除愈合早期速率或进展方面的差异。由于在TPLO术后8周时未发现年轻犬与老年犬在影像学愈合方面存在显著差异，因此无法拒绝零假设。前瞻性研究在术后2–12周内以频繁间隔评估TPLO影像学骨愈合，一致发现无需额外干预的常规愈合发生在8–12周内（14, 15）。然而，尽管Franklin等提出，术后7周和10周时组间骨愈合评分的轻微差异更可能归因于其组间犬年龄的差异，而非富血小板血浆的使用（15），但那些研究均未评估年龄对骨愈合的影响。在本研究中，影像学截骨愈合在术后约8周时进行评估，因为这代表了参与医院的常规随访方案。该评估时间在研究人群中相对一致，随访X线片获取时间中位数为56天。图1：胫骨平台水平截骨术（TPLO）后约8周获得的代表性正交X线片，展示使用改良胫骨骨折影像学愈合评分（mRUST）评估的四个皮质。在内外侧位投影（A）上识别头侧皮质（蓝色箭头）和尾侧皮质（红色虚线箭头），在头尾位投影（B）上识别内侧皮质（红色虚线箭头）和外侧皮质（蓝色箭头）。根据影像学截骨愈合程度，每个皮质被赋予1至4分的mRUST评分，四个皮质评分相加生成总mRUST评分，范围为4至16分。表1：按评估方法比较各年龄组改良胫骨骨折影像学愈合评分（mRUST）。评估方法：组1（n = 49）中位数（IQR）范围；组2（n = 51）中位数（IQR）范围；p值*。LLM：12（11–12）8–13；12（11–12）8–14；0.352。外科医生：12（10–13）8–15；11（10–13）8–16；0.908。住院医师：11（10–13）8–16；11（10–12）9–16；0.588。数据以中位数（四分位距[IQR]）和范围表示。组1包括2–5岁犬（n = 49），组2包括8–12岁犬（n = 51）。LLM，大语言模型；mRUST，改良胫骨骨折影像学愈合评分。p值代表使用Wilcoxon秩和检验比较各年龄组间总mRUST评分。*p值比较同一评估方法下年龄组1与年龄组2犬的评分。
Anderson 等，10.3389/fvets.2026.1934451，Frontiers in Veterinary Science，05，frontiersin.org，术后（范围，54–65 天）。尽管该时间点对于术后决策具有临床相关性（11），但在单一时间间隔进行评估限制了对截骨愈合进展的评估。可能的情况是，年龄相关差异在愈合过程早期即已存在，但至 8 周时已无法检测到。例如，年轻犬可能表现出更早的成骨启动或更快的成骨进展，而老年犬在 8 周评估时达到相似的放射学愈合评分。因此，8 周时未检测到差异不应被解释为年龄组之间截骨愈合的速率或模式等同的证据。需要纳入连续放射学评估的前瞻性研究，以确定实际年龄是否影响 TPLO 术后放射学截骨愈合的速率。年龄组之间无统计学显著差异应谨慎解读。一种可能的解释是，在所评估的术后 8 周时间点，仅实际年龄并不代表 TPLO 术后放射学截骨愈合的临床相关决定因素。该发现支持继续使用标准化放射学评估来指导术后随访和客户咨询，而非仅根据患者年龄修改预期。从临床角度来看，这些发现提示，仅实际年龄可能并不表明 TPLO 术后约 8 周时放射学截骨愈合延迟的预期；然而，不能排除小的年龄相关差异。或者，缺乏统计学显著差异可能反映研究设计固有的局限性，而非基于年龄的愈合差异。本研究的回顾性性质、对单一术后时间点的评估以及患者特征的可变性可能降低了检测细微或延迟愈合差异的能力。尽管存在可能影响愈合的其他合并症的犬被排除，但本研究中未评估的因素，如可能影响放射学愈合的骨质量或术后活动水平，无法进行分析。这些发现提示，虽然不应假定仅实际年龄可预测 TPLO 术后放射学愈合延迟，但有必要开展纳入多个术后时间点和功能结局指标的前瞻性研究，以更全面地描述年龄、放射学愈合与临床恢复之间的关系。另一个局限性是使用实际年龄来定义研究分组。生物学衰老在犬之间存在差异，并可能受品种、体型、遗传学和个体健康状况等因素影响；因此，相同实际年龄的犬可能不处于等效的生物学衰老阶段。入组限于体重 20–40 kg 的犬，以减少与不同体型相关的一些变异性。本研究中使用的预定义年龄范围旨在在年轻和老年成年犬群体之间建立区分，而非代表标准化的生物学衰老类别。未来纳入额外生物学或生理学衰老指标的研究可能更好地描述衰老与放射学截骨愈合之间的关系。本研究的次要目的是评估 LLM 辅助与人工 mRUST 评估之间的一致性。LLM 辅助评分显示出比人工观察者评分更窄的分布，62% 的犬总 mRUST 评分为 12，88% 的评分在 10 至 12 之间。三种评估方法之间的一致性为中等。重要的是，本研究旨在评估一致性而非诊断准确性。没有可用的放射学截骨愈合独立参考标准；因此，LLM 与人工观察者之间的不一致无法确定哪种评估更准确。同样，LLM 辅助评分较窄的分布不应必然被解释为更高的一致性 or 更优的性能，因为这种聚集可能反而反映对放射学表现细微差异的敏感性降低。这些发现支持在得出关于诊断准确性或临床实用性的结论之前，使用经过验证的参考标准对 LLM 辅助 mRUST 评估进行进一步研究。图 2 显示了年轻犬（第 1 组；2–5 岁，n = 49）和老年犬（第 2 组；8–12 岁，n = 51）在胫骨平台水平截骨术后约 8 周时总改良胫骨骨折放射学愈合评分（mRUST）的分布。图中显示了（A）LLM 评估、（B）委员会认证外科医师评估和（C）外科住院医师评估的个体 mRUST 评分。对于 LLM 辅助评估（p = 0.352）、外科医师评估（p = 0.908）或住院医师评估（p = 0.588），年龄组之间未发现 mRUST 评分的显著差异。
Anderson等，10.3389/fvets.2026.1934451，《Frontiers in Veterinary Science》06 frontiersin.org，三种评估方法之间的一致性为中等，而外科医生与住院医师之间的一致性则显著更高。在讨论计算机辅助评分方法用于放射影像解读时，现有人类和兽医肌肉骨骼影像学领域的证据突出了几个关键考量。第一，大量研究报告称，大语言模型辅助解读可以达到与受过训练临床医生相似的骨折检测性能，尽管这一准确度水平并非普遍适用（16）。第二，系统综述表明，尽管大语言模型总体有效，但在识别细微放射学异常方面仍面临挑战（17）。第三，特别是在兽医领域，比较研究显示大语言模型辅助解读可能接近但无法完全替代委员会认证的放射科医师，其作用更可能是增强而非替代人类解读（18）。在截骨愈合评分背景下（例如我们使用mRUST系统），LLM辅助评分的聚集性可能限制检测放射学截骨愈合或重塑细微差异的能力。因此，未来工作应致力于人类-大语言模型联合工作流程，将大语言模型辅助解读输出与功能/临床结局（步态分析、测力板）进行校准，并探索在此类特定截骨术后愈合数据集而非仅原发骨折检测上的算法训练。年龄组之间存在若干潜在混杂变量差异，包括植入物系统和尾内侧半半月板切除术的频率。植入物类型理论上可通过钢板设计和结构力学的差异影响放射学截骨愈合，这可能改变截骨部位的稳定性和骨折块间运动。尽管本研究中使用的两种植入物系统均为锁定TPLO钢板，且两种系统均进行了截骨加压，但螺钉配置和植入物设计存在差异。本研究并非专门设计用于评估植入物系统对放射学截骨愈合的影响；因此，不能排除植入物选择的影响。半月板切除术在老年犬中也更频繁地进行。由于尾内侧半半月板切除术是在手术中发现半月板病变时进行的，这一差异可能反映年龄组之间 underlying 膝关节疾病严重程度或慢性程度的变化。半月板病变及其治疗可能潜在地影响术后关节炎症、舒适度、肢体使用和手术肢体的负重，尽管本研究尚未确定半月板切除术对截骨愈合的直接作用。然而，植入物类型和半月板切除术在年龄组之间的不均衡分布代表了潜在的混杂来源，在解释实际年龄与放射学截骨愈合之间的关系时应予以考虑。此外，尽管在放射学评估期间手术住院医师未参考或不知晓患者年龄和年龄组，且人类观察者独立对放射影像进行评分，但住院医师参与了病例识别和数据收集，因此并未对其他患者信息完全设盲。与不完全设盲相关的观察者偏倚可能性不能完全排除。放射影像质量、麻醉管理、围手术期和术后用药方案、手术技术和康复方案在所有病例中也未标准化。可用样本量超过了每组检测mRUST总评分1.5分差异所需的最低估计45只犬（80%功效）。然而，年龄组之间较小的差异可能未被检测到，不能排除。此外，对多机构真实世界病例的回顾性评估增强了外部有效性和临床适用性。最后，尽管放射学截骨愈合是临床决策中的关键决定因素，但它可能无法完全反映机械强度或功能恢复。放射影像仍是术后评估最广泛使用的工具，但将标准化评分与客观结局指标配对应成为未来研究的优先事项。本研究发现，接受TPLO的年轻犬和老年犬在8周放射学截骨愈合评分上无统计学显著差异。在本研究的局限性内，实际年龄与评估术后时间点的mRUST评分无关；然而，不能排除较小的年龄相关差异或愈合过程早期出现的差异。mRUST系统显示两名人类观察者之间的一致性大于所有三种评估方法中观察到的总体一致性。由于没有可用的独立参考标准，无法确定LLM辅助评分的诊断准确性。这些发现表明，仅实际年龄可能不是TPLO后约8周放射学截骨愈合的可靠预测因素，并支持在制定术后建议时继续使用个体放射学评估。在确定LLM辅助放射学截骨评分的临床效用之前，需要进一步研究纳入标准化LLM方法学、独立参考标准和前瞻性验证。数据可用性声明 本研究中呈现的原始贡献包含在文章/补充材料中，进一步查询可联系通讯作者。伦理声明 根据当地立法和机构要求，涉及动物的研究不需要伦理批准，因为这是对现有医疗记录和放射影像的回顾性审查，没有专门为研究目的进行干预或程序。未获得动物主人关于其动物参与本研究的书面知情同意，因为这是对现有医疗记录和放射影像的回顾性审查，没有专门为研究目的进行干预或程序。作者贡献 BA：项目管理、写作——审阅与编辑、形式分析、方法学、写作——原始草稿、验证、调查、数据管理、可视化、资源、概念化。SF：方法学、概念化、项目
Anderson等，10.3389/fvets.2026.1934451，《Frontiers in Veterinary Science》07 frontiersin.org，给药、研究、监督、验证、写作——审阅与编辑、形式分析、资金获取、资源。CP：项目管理、概念化、方法学、验证、可视化、监督、写作——审阅与编辑、研究、资源、软件。资金 作者声明本研究及/或其发表未获得资金支持。致谢 作者感谢George E. Moore，DVM，PhD，DACVIM（SAIM），DACVIM（Epi）在统计分析方面提供的协助。利益冲突 作者声明本研究是在不存在任何可被解释为潜在利益冲突的商业或财务关系的情况下进行的。生成式AI声明 作者声明在本稿件的创作中未使用生成式AI。本文图表旁提供的任何替代文本（alt text）均由Frontiers在人工智能支持下生成，并已尽合理努力确保准确性，包括在可能情况下由作者审阅。如您发现任何问题，请联系我们。出版者注 本文中表达的所有主张仅代表作者本人，不一定代表其所属组织、出版者、编辑和审稿人的观点。本文中可能评估的任何产品或其制造商可能作出的任何主张，均不受出版者保证或认可。补充材料 本文的补充材料可在线获取，网址为：https://www.frontiersin.org/articles/10.3389/fvets.2026.1934451/full#supplementary-material 参考文献 1. von Pfeil DJF, Kowaleski MP, Glassman M, Dejardin LM. 兽医骨科协会会员对体重超过15千克（33磅）犬颅交叉韧带断裂首选治疗方法的调查结果。J Am Vet Med Assoc.（2018）253:586–97. doi: 10.2460/javma.253.5.586 2. Slocum B, Slocum TD. 胫骨平台水平化截骨术治疗颅交叉韧带断裂：原理与生物力学。Vet Clin North Am Small Anim Pract.（1993）23:777–95. doi: 10.1016/s0195-5616(93)50082-7 3. Warzee CC, Dejardin LM, Arnoczky SP, Perry RL. 胫骨平台水平化对犬颅交叉韧带缺陷膝关节胫骨前向和后向推力的影响：一项体外实验研究。Vet Surg.（2001）30:278–86. doi: 10.1053/jvet.2001.21400 4. Wagner DR, Karnik S, Gunderson ZJ, Nielsen JJ, Fennimore A, Promer HJ, 等. 功能失调的干细胞和祖细胞随年龄增长损害骨折愈合。World J Stem Cells.（2019）11:281–96. doi: 10.4252/wjsc.v11.i6.281 5. Lu C, Miclau T, Hu D, Hansen E, Tsui K, Puttlitz C, 等. 骨折修复年龄相关变化的细胞学基础。J Orthop Res.（2005）23:1300–7. doi: 10.1016/j.orthres.2005.04.003.1100230610 6. Innes JF, Bacon D, Lynch C, Pollard A. 犬颅交叉韧带缺陷手术的长期结果。Vet Rec.（2000）147:325–8. doi: 10.1136/vr.147.12.325 7. Wemmers AC, Charalambous M, Harms O, Volk HA. 使用胫骨平台水平化截骨术或胫骨结节前移术手术治疗犬颅交叉韧带疾病：一项采用荟萃分析方法的系统综述。Front Vet Sci.（2022）9:1004637. doi: 10.3389/fvets.2022.1004637 8. Leal RA, Lambrechts NE, Crowley JD, Griffin JF IV, Karnia JJ, Torres BT, 等. 犬胫骨平台水平化截骨术后骨愈合评估的放射学评分系统比较。Front Vet Sci.（2023）10:1147386. doi: 10.3389/fvets.2023.1147386 9. Lazar TP, Berry CR, DeHaan JJ, Peck JN, Correa M. 犬颅交叉韧带断裂胫骨平台水平化截骨术与囊外稳定术的长期放射学比较。Vet Surg.（2005）34:133–41. doi: 10.1111/j.1532-950X.2005.00021.x 10. Marin K, Unis MD, Horgan JE, Roush JK. 体重低于15千克犬胫骨平台水平化截骨术后8周内短期术后并发症的危险因素：一项回顾性研究。PLoS One.（2021）16:e0247555. doi: 10.1371/journal.pone.0247555 11. Huerta Y, Filliquist B, Agnello KA, Syrcle JA, Chou P-Y, Garcia TC, 等. 使用两种放射学评分系统评估接受胫骨平台水平化截骨术的拳师犬的截骨愈合。Vet Comp Orthop Traumatol.（2025）38:34–40. doi: 10.1055/s-0044-1788908 12. Whelan DB, Bhandari M, Stephen D, Kreder H, McKee M, Zdero R, 等. 用于评估髓内固定后胫骨骨折愈合的胫骨骨折放射学愈合评分系统的开发。J Trauma.（2010）68:629–32. doi: 10.1097/TA.0b013e3181a7c16d 13. Cook JL, Evans R, Conzemius MG, Lascelles BD, McIlwraith CW, Pozzi A, 等. 兽医临床骨科研究报告时间范围、结局和并发症的拟议定义和标准。Vet Surg.（2010）39:905–8. 14. Kieves NR, MacKay CS, Adducci K, Rao S, Goh C, Palmer RH, 等. 高能聚焦冲击波疗法加速骨愈合。一项盲法、前瞻性、随机犬临床试验。Vet Comp Orthop Traumatol.（2015）28:425–32. doi: 10.3415/VCOT-15-05-0084 15. Franklin SP, Burke EE, Holmes SP. 富血小板血浆对接受高位胫骨截骨术犬骨愈合的影响。PLoS One.（2017）12:e0177597. doi: 10.1371/journal.pone.0177597 16. Nowroozi A, Salehi MA, Shobeiri P, Agahi S, Momtazmanesh S, Kaviani P, 等. 人工智能在平片骨折检测中的诊断准确性及其与临床医生的比较：一项系统综述和荟萃分析。Clin Radiol.（2024）79:579–88. doi: 10.1016/j.crad.2024.04.009 17. Husarek J, Hess S, Razaeian S, Ruder TD, Sehmisch S, Müller M, 等. 商业骨折检测产品中的人工智能：诊断测试准确性的系统综述和荟萃分析。Sci Rep.（2024）14:73058. doi: 10.1038/s41598-024-73058-8 18. Joslyn SK, Faulkner J, Ma D, Appleby R. 评论：兽医放射科医生与最先进商业AI软件对犬猫放射学检查的放射学解读比较。Front Vet Sci.（2025）12:1615947. doi: 10.3389/fvets.2025.1615947
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Frontiers in Veterinary Science01frontiersin.org TYPE Original Research PUBLISHED 06 October 2026 DOI 10.3389/fvets.2026.1934451 OPEN ACCESS EDITED BY Antonio González Cantalapiedra, University of Santiago de Compostela, Spain REVIEWED BY Mario García-González, University of Santiago de Compostela, Spain Pedro Figueirinhas Paiva, University of Las Palmas de Gran Canaria, Spain *CORRESPONDENCE Bridget L. Anderson bridget.anderson@bluepearlvet.com RECEIVED 10 July 2026 REVISED 31 August 2026 ACCEPTED 21 September 2026 PUBLISHED 06 October 2026 CITATION Anderson BL, Frederick SW and Popovitch C (2026) Assessment of radiographic healing after tibial plateau leveling osteotomy in young and older dogs using the modified RUST scoring system. Front. Vet. Sci. 13:1934451. doi: 10.3389/fvets.2026.1934451 COPYRIGHT © 2026 Anderson, Frederick and Popovitch. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Assessment of radiographic healing after tibial plateau leveling osteotomy in young and older dogs using the modified RUST scoring system Bridget L. Anderson 1 *, Steven W. Frederick 2 and Catherine Popovitch 1 1 BluePearl Pet Hospital, Levittown, PA, United States, 2 BluePearl Science, Tampa, FL, United States Objective: To compare radiographic osteotomy healing scores after tibial plateau leveling osteotomy (TPLO) in young (2–5 years) and old (8–12 years) dogs using the modified Radiographic Union Score for Tibial fractures (mRUST) system, and to evaluate agreement between large language model-assisted interpretation (LLM), surgeon, and surgical resident scoring. Study design: Client-owned, 20–40 kg dogs treated with unilateral TPLO at ages 2–5 or 8–12 years between 2023 and 2025 were retrospectively identified. Dogs with endocrinopathy or atypical TPLO or recovery were excluded. Dogs were assigned to Group 1 (2–5 years) or Group 2 (8–12 years). 8-week postoperative radiographs were scored independently by an LLM, a surgeon, and a surgical resident using the 4-point mRUST system. Scores were compared between age groups using the Wilcoxon rank-sum test, and interrater agreement was assessed using an intraclass correlation coefficient (ICC). Results: Group 1 had 49 dogs; Group 2 had 51 dogs. Group 1 had a mean (SD) age of 3.82 (1.11) years, while Group 2 had a mean (SD) age of 9.24 (0.99) years. mRUST scores did not differ between age groups across LLM (p = 0.352), surgeon (p = 0.908), or resident assessments (p = 0.588). LLM, surgeon, and resident scores had only fair agreement (ICC = 0.4504, p < 0.001). Conclusion: Chronological age was not associated with mRUST score following TPLO at the 8-week postoperative evaluation. The mRUST system demonstrated moderate agreement between human observers. LLM scoring showed promise; further refinement is needed for clinical application. KEYWORDS age, dog, osteogenesis, radiographic osteotomy healing, tibial plateau leveling osteotomy Introduction Cranial cruciate ligament disease (CCLD) is a common cause of hindlimb lameness in dogs. The tibial plateau leveling osteotomy (TPLO) procedure has become a standard surgical intervention for CCL rupture (1). The procedure restores stability to the stifle joint by neutralizing cranial tibial thrust during the stance phase of gait by decreasing the tibial plateau angle (2, 3). However, it is important to note that post-procedure bone healing is a crucial determinant of success, as it affects the recovery time and the dog’s ability to return to full function.
Anderson et al. 10.3389/fvets.2026.1934451 Frontiers in Veterinary Science02frontiersin.org Studies of humans have demonstrated that aging can be a risk factor for fractures due to decreased bone mass and bone quality (4). Additionally, differences in bone healing in mice and identified delayed chondrocyte differentiation and maturation, as well as impaired vascular invasion and bone formation in older animals compared to the younger group (5). This aligns with previous reports of delayed fracture healing in the elderly population, likely resulting from a lower capacity for mesenchymal stem cell differentiation and impaired angiogenesis/vasculogenesis (4). Despite the significance of age-related differences in bone healing identified in human medicine, limited studies have specifically compared radiographic bone healing between different age groups of dogs following TPLO surgery. Existing clinical literature has focused on clinical outcomes such as pain management, lameness resolution, gait analysis, osteoarthritis development, goniometry, and complication rates without specifically quantifying differences in bone healing based on age (6, 7). Therefore, a better understanding of how age influences bone healing outcomes is crucial for veterinarians to optimize postoperative care, tailor rehabilitation protocols, and provide accurate prognoses to pet owners. Radiographic assessment of bone healing following TPLO plays a central role in postoperative clinical decision-making, including recommendations for activity restriction, progression of rehabilitation, and timing of follow-up evaluations. Although subjective interpretation of radiographs remains common in clinical practice, objective scoring systems have been increasingly adopted to standardize assessment. Various scales have been used to evaluate radiographic bone healing objectively, including variations on 5-, 10-, and 12-point scales (8–10). Each scoring system presents unique challenges, and currently, a single, standardized scoring system for evaluating osteotomy healing has not been established in veterinary medicine (11). The modified Radiographic Union Score for Tibial Fractures (mRUST), previously developed for human orthopedic medicine (12), has been adapted for veterinary applications to quantitatively assess cortical healing based on the presence of callus or a persistent fracture line (8). The objective of this study was to evaluate the association between chronologic age and radiographic osteotomy healing following TPLO using the mRUST scoring system, with the aim of determining whether age alone is a reliable predictor of delayed radiographic union at a standardized postoperative time point. Our null hypothesis was that radiographic bone healing scores at 8 weeks postoperatively would not differ between younger (2–5 years) and older (8–12 years) dogs undergoing TPLO. Methods Study design and case selection This retrospective cohort study evaluated radiographic osteotomy healing following TPLO in dogs treated at three private practice referral hospitals in Philadelphia, Pennsylvania, USA. Electronic medical records from three private practice referral hospital settings in Philadelphia, Pennsylvania, USA were retrospectively reviewed to identify dogs weighing 20–40 kg that underwent unilateral TPLO between January 2023 and January 2025. Dogs were categorized into two predefined age groups based on chronologic age at the time of surgery: Group 1 included dogs aged 2–5 years and Group 2 included dogs aged 8–12 years. Dogs aged 6–7 years were excluded to increase separation between the age groups for evaluation of a potential ageassociated difference in radiographic osteotomy healing. A minimum of 45 dogs per group was estimated to provide 80% power at a twosided α of 0.05 to detect a between-group difference in total mRUST score of 1.5 points, assuming a standard deviation of ≤2.5 points. Dogs were included if they had a routine unilateral TPLO, as described by Slocum, when they were between the ages of 2–5 years (Group 1) or 8–12 years (Group 2) without any major complications on physical or radiographic examination during the first 8 postoperative weeks (2, 13). Furthermore, inclusion criteria involved complete medical records and available orthogonal stifle radiographs. Dogs were excluded if they were outside the predefined age ranges for Groups 1 and 2 at the time of surgery; had evidence of systemic disease based on hematologic and/or serum biochemical evaluation; experienced a major complication during or after surgery, as defined by Cook et al. (13); lacked complete medical records or postoperative radiographs; were receiving concurrent corticosteroid therapy; or had concurrent orthopedic or neurologic conditions identified at the time of surgery (e.g., medial patellar luxation, neuromuscular disease, or tendinopathy). Surgical procedure Anesthetic protocols were not standardized across cases or participating institutions. Premedication, induction, maintenance, and perioperative analgesic protocols were selected by the anesthetist based on individual patient factors, including age, physical status, concurrent medical considerations, and preference. Therefore, anesthetic protocols differed between younger and older dogs. Specific anesthetic protocols were not evaluated as variables in the present study. All TPLO procedures were performed by either a board-certified veterinary surgeon or an American College of Veterinary Surgeons resident under the direct supervision of a board-certified surgeon. Parapatellar mini-arthrotomies were performed in all dogs to confirm the diagnosis of CCL rupture. All CCLs were debrided at time of arthrotomy. If meniscal pathology was present at the time of surgery, a caudomedial hemimeniscectomy was performed. A curvilinear osteotomy was performed routinely using an oscillating radial blade. Internal fixation of the osteotomy was performed using locking TPLO plates with two different implant systems (DePuy Synthes Vet, Paoli, PA, and Arthrex Vet Systems, Naples, FL). Each dog who received a Synthes implant had two cortical screws placed distal to the osteotomy, with the remaining holes filled with locking screws. For each dog that received the Arthrex implant, one cortical screw was placed distal to the osteotomy, with the remaining holes filled with locking screws. All osteotomies were compressed using the compression hole with each TPLO plate. Each dog received appropriately sized implants, at the surgeon’s discretion, at the time of surgery. Routine closure was performed following all screw placements. Postoperative orthogonal radiographs of the tibia to include the stifle proximally and tarsus distally were obtained immediately following surgery and at approximately 8 postoperative weeks. Confirmation of appropriate implant positioning, sizing, and sufficient tibial plateau angle modification was assessed for each radiograph to complete the case. Dogs recovered with the surgical service and were discharged with instructions regarding postoperative incision care, activity restrictions, and medication. All dogs in the study were discharged with an antibiotic medication (cefpodoxime 5–10 mg/kg PO q 24 h x 7–14 days or cephalexin 22 mg/kg PO q 12 h x 7–14 days), a
Anderson et al. 10.3389/fvets.2026.1934451 Frontiers in Veterinary Science03frontiersin.org non-steroidal anti-inflammatory medication (carprofen 2.2 mg/kg PO q 12 h), additional pain medication (gabapentin 10 mg/kg PO q 8 h), and a sedative (trazodone 5 mg/kg PO q 8 h). The duration of gabapentin and trazodone administration was not standardized across participating institutions and was individualized according to patient comfort, behavior, activity restrictions needed, clinician discretion, and owner-reported concerns. Similarly, standardized criteria for medication refills were not established, and additional gabapentin or trazodone was prescribed when deemed clinically appropriate based on individual patient needs. Follow-up rechecks were performed through the surgical department at 2 postoperative weeks (via a virtual recheck for incision evaluation and gait analysis) and 8 postoperative weeks for physical and radiographic examinations. If concerns were noted via virtual recheck or if owner concerns were reported, in-person rechecks were performed for further assessment. Owners were given postoperative activity instructions following completion of the initial 2-week recheck, which included increasing slow, controlled leash walks up to 10 min daily, with increments of 5 min weekly, until the in-person 8-week recheck. Refills of sedative or pain medications were provided upon request. Radiographic evaluation All 8-week follow-up radiographs were collected for evaluation by a small animal surgical resident (BA), a board-certified small animal surgeon (CP), and an LLM assessment method. The board-certified surgeon was provided only anonymized radiographs and was blinded to patient identity, clinical information, chronological age, and age group. The surgical resident was responsible for case identification, data collection, and radiograph collection and therefore had access to patient identifying and clinical information; however, patient age and age group were not referenced at the time of radiographic scoring. The surgeon and surgical resident performed their assessments independently and were blinded to each other’s mRUST scores. The LLM was not provided with patient identity, clinical information, chronological age, age group, or scores assigned by human raters. Osteotomy site healing was scored using the mRUST scoring system. Four cortices were independently evaluated on orthogonal radiographic projections: the cranial and caudal cortices on the mediolateral projection and the medial and lateral cortices on the craniocaudal projection. Each cortex was assigned a score from 1 to 4 according to the degree of radiographic healing: 1 = no callus formation with a clearly visible osteotomy line; 2 = callus formation with a persistent visible osteotomy line; 3 = bridging callus with an indistinct or absent osteotomy line; 4 = complete cortical remodeling with restoration of cortical continuity and no visible osteotomy line. Scores from the four cortices were summed to generate a total mRUST score ranging from 4 to 16, with higher scores representing greater radiographic osteotomy healing. The same scoring criteria were used by all three assessment methods: a small animal surgical resident, a boardcertified surgeon, and LLM-assisted interpretation. All human-assessed images were evaluated using a single PACS program (Keystone Asteris, Montreal, Canada). For large-language model-assisted assessment, postoperative orthogonal TPLO radiographs were uploaded to ChatGPT (OpenAI, San Francisco, CA, USA) in June 2025. The specific underlying model version available through the ChatGPT interface at the time of assessment was not recorded. Multiple dogs were evaluated sequentially within the same conversation. The same standardized instructions and mRUST scoring criteria were provided for each case. Prior to scoring, the model was instructed to review the predefined mRUST criteria and subsequently assign an individual score from 1 to 4 to each of the cranial, caudal, medial, and lateral cortices based on corresponding orthogonal radiographic views (Figure 1). The four cortical scores were recorded and summed to generate a total mRUST score ranging from 4 to 16. The same prompt was used for evaluating each radiograph and has been provided in Supplementary material 1. Statistical analysis Continuous numerical variables were assessed for normality with the Shapiro–Wilk test. Parametrically distributed numerical variables were summarized as mean ± standard deviation (SD), and ordinal and nonparametrically distributed numerical variables are summarized with median and interquartile range (IQR). Parametrically distributed numerical variables were compared using the Student’s t-test, and nonparametrically distributed numerical variables were compared with the Wilcoxon rank sum test. Frequency distributions between categorical variables were compared with the chi-square test of independence. Total mRUST scores were compared between age groups for each assessment method using the Wilcoxon rank-sum test. Statistical significance was set at α = 0.05. Interrater agreement for total mRUST scores among the LLM, surgeon, and resident was assessed using a single-measure, absolute agreement intraclass correlation coefficient (ICC) based on a one-way random-effects model, with 95% confidence intervals. Agreement between surgeon and surgical resident total mRUST scores was also assessed separately using the same method. Results A total of 439 dogs were initially identified. Eighty-seven (19.8%) were excluded due to loss of follow-up, 130 (29.6%) did not meet the age or weight criteria for enrollment, 43 (9.8%) underwent simultaneous bilateral TPLO procedures, and 79 (18%) had previously undergone TPLO on the contralateral limb. The remaining 100 dogs (22.8%) met all inclusion criteria, with 49 dogs assigned to Group 1 and 51 dogs assigned to Group 2. Group 1 included 29 (59.2%) spayed females and 20 (40.8%) neutered males, while Group 2 included 26 (51.0%) spayed females, 23 (45.1%) neutered males, and 2 (3.9%) intact males. Mixed-breed dogs were the most common in both groups (51.0% in Group 1 and 60.8% in Group 2), followed by Labrador Retrievers, Pitbulls, and Golden Retrievers. The median interval between surgery and follow-up radiographs was 56 days (range, 54–65 days). Age differed due to study design; Group 1 had a mean (SD) age of 3.82 (1.11) years, while Group 2 had a mean (SD) age of 9.24 (0.99) years. Group 1 dogs were slightly heavier than Group 2 dogs (median weight 32.6 [IQR: 29.0–34.6] kg and 29.9 [IQR: 24.0–34.3] kg, respectively; p = 0.007). Sex distribution did not significantly differ between groups (p = 0.311). Implant type differed significantly between groups: 75.5% of dogs in Group 1 received Arthrex implants, compared to 54.9% in Group 2 (p = 0.031). The majority (58.8%) of dogs in group 2 underwent meniscectomy, compared to 34.7% in Group 1 (p = 0.016).
Anderson et al. 10.3389/fvets.2026.1934451 Frontiers in Veterinary Science04frontiersin.org LLM-assessed, surgeon-assessed, and resident-assessed total mRUST scores did not significantly differ between age groups (p = 0.352, p = 0.908, and p = 0.588, respectively; Table 1; Figure 2). Median, interquartile range, and range of mRUST scores for each assessment method and age group are summarized in Table 1. LLM-assessed mRUST scores, surgeon-assessed scores, and resident-assessed scores demonstrated fair interrater agreement [singlemeasure, absolute agreement (AA) ICC = 0.4504 (95% CI: 0.3305–0.5664; p < 0.001)]. Agreement between surgeon-assessed scores and resident-assessed scores was stronger [single-measure, AA ICC = 0.7923 (95% CI: 0.7065–0.8552; p < 0.001)]. Discussion This retrospective cohort study found no statistically significant difference in 8-week radiographic osteotomy healing scores between younger and older adult dogs undergoing TPLO using the mRUST scoring system These findings suggest that chronological age was not associated with radiographic osteotomy healing at the evaluated postoperative time point; however, differences in the earlier rate or progression of healing cannot be excluded. The null hypothesis could not be rejected, as no significant differences in radiographic healing were identified between younger and older dogs at 8 weeks following TPLO. Prospective studies evaluating TPLO radiographic bone healing at frequent intervals over 2–12 postoperative weeks have consistently found that routine healing with no additional intervention occurs within 8–12 weeks (14, 15). However, none of those studies evaluated the impact of age on bone healing, despite Franklin et al. positing that slightly different bone healing scores between groups at 7 and 10 postoperative weeks was likely attributed more to differences in dog age between their groups rather than the use of platelet rich plasma (15). In our study, radiographic osteotomy healing was evaluated at approximately 8 weeks postoperative because this represents the routine follow-up protocol at contributing hospitals. The timing of this evaluation was relatively consistent across the study population, with follow-up radiographs obtained at a median of 56 days FIGURE 1 Representative orthogonal radiographs obtained approximately 8 weeks following tibial plateau leveling osteotomy (TPLO), demonstrating the four cortices evaluated using the modified Radiographic Union Score for Tibia fractures (mRUST). The cranial (blue arrow) and caudal (red dotted arrow) cortices are identified on the mediolateral projection (A), and the medial (red dotted arrow) and lateral (blue arrow) cortices are identified on the craniocaudal projection (B). Each cortex was assigned an mRUST score from 1 to 4 based on the degree of radiographic osteotomy healing and the four cortical scores were summed to generate a total mRUST score ranging from 4 to 16. TABLE 1 Comparison of modified Radiographic Union Scores for Tibial fractures (mRUST) scores between age groups by assessment method. Assessment methodGroup 1 (n = 49)Group 2 (n = 51)p-value* Median (IQR)RangeMedian (IQR)Range LLM12 (11–12)8–1312 (11–12)8–140.352 Surgeon12 (10–13)8–1511 (10–13)8–160.908 Resident11 (10–13)8–1611 (10–12)9–160.588 Data are presented as median (interquartile range [IQR]) and range. Group 1 included dogs 2–5 years of age (n = 49), and Group 2 included dogs 8–12 years of age (n = 51). LLM, large language model; mRUST, modified Radiographic Union Score for Tibial fractures. p-values represent comparisons of total mRUST scores between age groups using the Wilcoxon rank-sum test. *p-value comparing same assessment method scores for age group 1 to scores for age group 2 dogs.
Anderson et al. 10.3389/fvets.2026.1934451 Frontiers in Veterinary Science05frontiersin.org postoperatively (range, 54–65 days). Although this time point is clinically relevant for postoperative decision-making (11), evaluation at a single interval limits assessment of the progression of osteotomy healing. It is possible that age-related differences may have been present earlier in the healing process but were no longer detectable by 8-weeks. For example, younger dogs may have demonstrated earlier onset or more rapid progression of osteogenesis, while older dogs reached similar radiographic healing scores by the 8-week evaluation. Therefore, the absence of detectable differences at 8-weeks should not be interpreted as evidence that the rate or pattern of osteotomy healing is equivalent between age groups. Prospective studies to include serial radiographic assessments are needed to determine whether chronological age influences the rate of radiographic osteotomy healing following TPLO. The absence of a statistically significant difference between age groups should be interpreted cautiously. One possible explanation is that chronological age alone does not represent a clinically relevant determinant of radiographic osteotomy healing following TPLO at the evaluated postoperative time point of 8-weeks. This finding supports the continued use of standardized radiographic assessment to guide postoperative follow-up and client counseling, rather than modifying expectations based solely on patient age. From a clinical perspective, these findings suggest that chronological age along may not show expectation of delayed radiographic osteotomy healing at approximately 8 weeks following TPLO; however, small age-related differences cannot be excluded. Alternatively, the lack of statistically significant differences may reflect limitations inherent to the study design rather than differences in healing based on age. The retrospective nature of this study, evaluation of a single postoperative time point, and variability in patient characteristics may have reduced the ability to detect subtle or delayed differences in healing. Although dogs were excluded if they had presence of other comorbidities that may affect healing, factors that were not evaluated in the current study such as bone quality or postoperative activity level that may have influenced radiographic healing were not available for analysis. These findings suggest that while chronologic age alone should not be assumed to predict delayed radiographic healing following TPLO, further prospective studies incorporating multiple postoperative time points and functional outcome measures are warranted to more fully characterize the relationship between age, radiographic healing, and clinical recovery. An additional limitation is the use of chronological age to define the study groups. Biological aging varies among dogs and may be influenced by factors including breed, body size, genetics, and individual health status; therefore, dogs of the same chronological age may not be at equivalent stages of biological aging. Enrollment was restricted to dogs weighing 20–40 kg to reduce some of the variability associated with different body sizes. The predefined age ranges used in this study were intended to create separation between younger and older adult populations rather than represent standardized biological aging categories. Future studies incorporating additional measures of biological or physiologic aging may better characterize the relationship between aging and radiographic osteotomy healing. A secondary aim of this study was to evaluate agreement between LLM-assisted and human mRUST assessment. LLM-assisted scores demonstrated a narrower distribution than scores assigned by the human observers, with 62% of dogs receiving a total mRUST score of 12 and 88% receiving scores between 10 and 12. Agreement among the three assessment methods was fair. Importantly, the present study was designed to evaluate agreement rather than diagnostic accuracy. No independent reference standard for radiographic osteotomy healing was available; therefore, disagreement between the LLM and human observers cannot establish which assessment was more accurate. Similarly, the narrower distribution of LLM-assisted scores should not necessarily be interpreted as greater consistency or superior performance, as this clustering may instead reflect reduced sensitivity to subtle differences in radiographic appearance. These findings support further investigation of LLM-assisted mRUST assessment using a validated reference standard before conclusions regarding diagnostic accuracy or clinical utility can be made. Agreement among FIGURE 2 Distribution of total modified Radiographic Union Score for Tibial fractures (mRUST) scores between younger (Group 1; 2–5 years, n = 49) and older (Group 2; 8–12 years, n = 51) dogs approximately 8 weeks following tibial plateau leveling osteotomy. Individual mRUST scores are shown for (A) LLM assessment, (B) board-certified surgeon assessment, and (C) surgical resident assessment. No significant differences in mRUST scores were identified between age groups for the LLM-assisted (p = 0.352), surgeon (p = 0.908), or resident (p = 0.588) assessments.
Anderson et al. 10.3389/fvets.2026.1934451 Frontiers in Veterinary Science06frontiersin.org all three assessment methods was fair, whereas agreement between the surgeon and resident was substantially greater. Existing evidence across both human and veterinary musculoskeletal imaging highlights several key considerations when discussing the use of a computer-assisted scoring approach in radiographic interpretations. First, numerous studies report that large language model-assisted interpretation can achieve fracture-detection performance similar to that of trained clinicians, though this level of accuracy is not universal (16). Second, systematic review indicates that while large language models are generally effective, they continue to face challenges in identifying subtle radiographic abnormalities (17). Third, in veterinary medicine specifically, comparative studies show large language model-assisted interpretation may approach but not fully replace board-certified radiologists, and its role is more likely to augment rather than replace human interpretation (18). In the context of osteotomy healing scoring (such as our use of the mRUST system), the clustering of LLM-assisted scores may limit the ability to detect subtle differences in radiographic osteotomy healing or remodeling. Therefore, future work should aim for combined humanlarge-language model workflows, incorporate calibration of large language model-assisted interpretation output with functional/clinical outcomes (gait-analysis, force plate) and explore algorithmic training on such specific post-osteotomy healing datasets rather than primary fracture detection alone. Several potential confounding variables differed between age groups, including implant system and frequency of caudomedial hemimeniscectomy. Implant type could theoretically influence radiographic osteotomy healing through differences in plate design and construct mechanics, which may alter stability and interfragmentary motion at the osteotomy site. Although both implant systems used in this study were locking TPLO plates and osteotomy compression was performed in both systems, differences in screw configuration and implant design were present. The study was not specifically designed to evaluate the effect of implant system on radiographic osteotomy healing; therefore, an effect of implant selection cannot be excluded. Meniscectomy was also performed more frequently in older dogs. Because caudomedial hemimeniscectomy was performed when meniscal pathology was identified at surgery, this difference may reflect variation in the severity or chronicity of underlying stifle disease between age groups. Meniscal pathology and its treatment could potentially influence postoperative joint inflammation, comfort, limb use, and loading of the operated limb, although a direct effect of meniscectomy on osteotomy healing has not been established in this study. Nevertheless, the unequal distribution of implant type and meniscectomy between age groups represents a potential source of confounding and should be considered when interpreting the relationship between chronological age and radiographic osteotomy healing. Additionally, although patient age and age group were not referenced or known to the surgical resident during radiographic assessment and the human observers scored the radiographs independently, the resident was involved in case identification and data collection and therefore was not completely blinded to other patient information. The potential for observer bias related to incomplete blinding cannot be entirely excluded. Radiographic quality, anesthetic management, perioperative and postoperative medication protocols, surgical technique, and rehabilitation protocols were also not standardized across all cases. The available sample size exceeded the estimated minimum of 45 dogs per group required to detect a 1.5- point difference in total mRUST score with 80% power. However, smaller differences between age groups may not have been detected and cannot be excluded. Moreover, retrospective evaluation of multiinstitutional, real-world cases enhances external validity and clinical applicability. Finally, although radiographic osteotomy healing is a critical determinant in clinical decision-making, it may not fully reflect mechanical strength or return of function. Radiographs remain the most widely used tool for postoperative evaluation, but pairing standardized scoring with objective outcome measures should be a priority for future research. This study found no statistically significant difference in 8-week radiographic osteotomy healing scores between younger and older dogs undergoing TPLO. Within the limitations of the present study, chronological age was not associated with mRUST score at the evaluated postoperative time point; however, smaller age-related differences or differences occurring earlier in the healing process cannot be excluded. The mRUST system demonstrated agreement between the two human observers was greater than the overall agreement observed among all three assessment methods. Because no independent reference standard was available, the diagnostic accuracy of LLM-assisted scoring could not be determined. These findings suggest that chronological age alone may not be a reliable predictor of radiographic osteotomy healing at approximately 8 weeks following TPLO and support the continued use of individual radiographic assessment when making postoperative recommendations. Further studies incorporating standardized LLM methodology, independent reference standards, and prospective validation are necessary before the clinical utility of LLM-assisted radiographic osteotomy scoring can be determined. Data availability statement The original contributions presented in the study are included in the article/Supplementary material, further inquiries can be directed to the corresponding author. Ethics statement Ethical approval was not required for the studies involving animals in accordance with the local legislation and institutional requirements because this is a retrospective review of existing medical records and radiographs, with no interventions or procedures performed specifically for research purposes. Written informed consent was not obtained from the owners for the participation of their animals in this study because this is a retrospective review of existing medical records and radiographs, with no interventions or procedures performed specifically for research purposes. Author contributions BA: Project administration, Writing – review & editing, Formal analysis, Methodology, Writing – original draft, Validation, Investigation, Data curation, Visualization, Resources, Conceptualization. SF: Methodology, Conceptualization, Project
Anderson et al. 10.3389/fvets.2026.1934451 Frontiers in Veterinary Science07frontiersin.org administration, Investigation, Supervision, Validation, Writing – review & editing, Formal analysis, Funding acquisition, Resources. CP: Project administration, Conceptualization, Methodology, Validation, Visualization, Supervision, Writing – review & editing, Investigation, Resources, Software. Funding The author(s) declared that financial support was not received for this work and/or its publication. Acknowledgments The authors thank George E. Moore, DVM, PhD, DACVIM (SAIM), DACVIM (Epi) for his assistance with the statistical analyses. Conflict of interest The author(s) declared that this work was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Generative AI statement The author(s) declared that Generative AI was not used in the creation of this manuscript. Any alternative text (alt text) provided alongside figures in this article has been generated by Frontiers with the support of artificial intelligence and reasonable efforts have been made to ensure accuracy, including review by the authors wherever possible. If you identify any issues, please contact us. Publisher’s note All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher. Supplementary material The Supplementary material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fvets.2026.1934451/ full#supplementary-material References 1. von Pfeil DJF, Kowaleski MP, Glassman M, Dejardin LM. 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