Moulton Samuel G, Provencher Matthew, Vidal Armando, Wiedrick Jack, Arnold Kaytee, Crawford Dennis
University of California San Francisco, San Francisco, California, USA.
The Steadman Clinic, Vail, Colorado, USA.
Orthop J Sports Med. 2023 Mar 6;11(3):23259671231153132. doi: 10.1177/23259671231153132. eCollection 2023 Mar.
Preoperative magnetic resonance imaging (MRI) is used to estimate the quantity of tissue provided for fresh osteochondral allograft (FOCA) in the knee. Use of 3-dimensional (3D) MRI modeling software for this purpose may improve defect assessment, providing a more accurate estimate of osteochondral allograft tissue required and eliminating the possibility of acquiring an inadequate quantity of tissue for transplant surgery.
To evaluate the capacity of damage assessment (DA) 3D MRI modeling software to preoperatively estimate the osteochondral allograft surface area used in surgery.
Cohort study (diagnosis); Level of evidence, 2.
Included were 36 patients who had undergone FOCA surgery to the distal femur. Based on the preoperative MRI scans, the DA software estimated the total surface area of the lesion as well as the surface areas of each subarea of injury: full-thickness cartilage injury (International Cartilage Repair Society [ICRS] grade 4), partial-thickness cartilage injury (ICRS grade 2-3), bone marrow edema, bone loss, and bone cyst. The probability of overestimation of graft tissue areas by the DA software was calculated using a Bayes-moderated proportion, and the relationship between the prediction discrepancy (ie, over- or underestimation) and the magnitude of the DA estimate was assessed using nonparametric local-linear regression.
The DA total surface area measurement overestimated the actual area of FOCA tissue transplanted 81.6% (95% CI, 67.2%-91.4%) of the time, corresponding to a median overestimation of 3.14 cm, or 1.78 times the area of FOCA transplanted. The DA software overestimated the area of FOCA transplanted 100% of the time for defect areas measuring >4.52 cm. For defects <4.21 cm, the maximum-magnitude underestimation of tissue area was 1.45 cm (on a fold scale, 0.63 times the transplanted area); a plausible heuristic is that multiplying small DA-measured areas of injury by a factor of ∼1.5 would yield an overestimation of the tissue area transplanted most of the time.
The DA 3D modeling software overestimated osteochondral defect size >80% of the time in 36 distal femoral FOCA cases. A policy of consistent but limited overestimation of osteochondral defect size may provide a more reliable basis for predicting the minimum safe amount of allograft tissue to acquire for transplantation.
术前磁共振成像（MRI）用于评估膝关节新鲜骨软骨异体移植（FOCA）所提供的组织量。使用三维（3D）MRI建模软件进行此操作可能会改善缺损评估，更准确地估计所需的骨软骨异体移植组织量，并消除移植手术中获取组织量不足的可能性。
评估损伤评估（DA）3D MRI建模软件术前估计手术中使用的骨软骨异体移植表面积的能力。
队列研究（诊断）；证据等级，2级。
纳入36例行股骨远端FOCA手术的患者。基于术前MRI扫描，DA软件估计病变的总表面积以及每个损伤子区域的表面积：全层软骨损伤（国际软骨修复协会[ICRS]4级）、部分层软骨损伤（ICRS 2-3级）、骨髓水肿、骨质流失和骨囊肿。使用贝叶斯调节比例计算DA软件高估移植组织面积的概率，并使用非参数局部线性回归评估预测差异（即高估或低估）与DA估计值大小之间的关系。
DA总表面积测量在81.6%（95%CI，67.2%-91.4%）的时间内高估了实际移植的FOCA组织面积，对应中位数高估3.14 cm，即移植的FOCA面积的1.78倍。对于测量面积>4.52 cm的缺损区域，DA软件在100%的时间内高估了移植的FOCA面积。对于<4.21 cm的缺损，组织面积的最大幅度低估为1.45 cm（以倍数计，为移植面积的0.63倍）；一个合理的经验法则是，将DA测量的小损伤面积乘以~1.5的系数，在大多数情况下会高估移植的组织面积。
在36例股骨远端FOCA病例中，DA 3D建模软件在80%以上的时间内高估了骨软骨缺损大小。对骨软骨缺损大小进行一致但有限的高估策略可能为预测移植所需的最低安全异体移植组织量提供更可靠的基础。
