MedSport, Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan, USA.
Department of Orthopedic Surgery, Mayo Clinic, Phoenix, Arizona, USA.
Am J Sports Med. 2022 May;50(6):1635-1643. doi: 10.1177/03635465221087391. Epub 2022 Apr 19.
Cartilage transplants in the patellofemoral joint have demonstrated lower success rates than in the femoral condyles. This is likely related to the more complex morphology and biomechanics of the joint. While previous studies have evaluated cartilage surface matching and congruence, little work has been done to study the associated subchondral bone congruency in these grafts.
To determine if differences in patellar morphology play a role in the alignment of the donor patellar osteochondral allograft subchondral bone with the native patellar subchondral bone.
Controlled laboratory study.
A total of 20 (10 Wiberg I and 10 Wiberg II/III) fresh-frozen human patellae were designated as recipients and size-matched to both a Wiberg I and a Wiberg II/III patellar donor. A 16-mm osteochondral allograft transplant to the central ridge of the patella was performed in random order with each matched donor. Transplanted patellae underwent a nano-computed tomography (nano-CT) scan, were digitally reconstructed, and were superimposed on the initial nano-CT scan of the native recipient patella. MATLAB was used to determine the surface height deviation between the native and donor subchondral bone surfaces. DragonFly 3-dimensional imaging software was used to measure subchondral bone step-off heights at the native-donor interface. Differences between matched and unmatched grafts were compared using a 2-way analysis of variance and the Sidak post hoc test.
Subchondral bone surface deviation did not differ between Wiberg matched and unmatched allografts. The step-off height was significantly greater in unmatched (1.38 ± 0.49 mm) compared with matched (1.14 ± 0.52 mm) plugs ( = .015). The lateral quadrant step-off differed between matched (0.89 ± 0.43 mm) and unmatched (1.60 ± 0.78 mm) grafts ( = .007).
While unmatched Wiberg patellar osteochondral allograft implantation did not result in significantly different subchondral bone surface height deviations, there was a significant difference in the circumferential subchondral bone step-off height in the lateral quadrant. Further investigation using finite element analysis modeling will help determine the role of subchondral bone surface on shear and compression force distributions in these areas.
Given that subchondral bone stiffness and morphology play a role in cartilage health, subchondral bone congruency may play a role in graft survival. Understanding how this congruency plays a role in cartilage force distribution will help surgeons improve the long-term success of osteochondral allograft transplants.
髌股关节的软骨移植成功率低于股骨髁。这可能与关节更复杂的形态和生物力学有关。尽管先前的研究已经评估了软骨表面匹配和一致性，但很少有研究致力于研究这些移植物中相关的软骨下骨一致性。
确定髌骨关节形态的差异是否会影响供体髌骨关节软骨移植的软骨下骨与正常髌骨关节软骨下骨的对齐。
对照实验室研究。
共 20 个（10 个 Wiberg I 型和 10 个 Wiberg II/III 型）新鲜冷冻的人髌骨被指定为受体，并与 Wiberg I 型和 Wiberg II/III 型髌骨供体进行尺寸匹配。随机顺序在每个匹配的供体上进行中央嵴的 16mm 骨软骨同种异体移植。移植后的髌骨进行纳米计算机断层扫描（nano-CT）扫描，数字化重建，并与初始接受者髌骨的 nano-CT 扫描叠加。使用 MATLAB 确定正常和供体软骨下骨表面之间的表面高度偏差。使用 DragonFly 3D 成像软件测量在原生-供体界面处的软骨下骨阶跃高度。使用双向方差分析和 Sidak 事后检验比较匹配和不匹配移植物之间的差异。
Wiberg 匹配和不匹配同种异体移植物的软骨下骨表面偏差没有差异。不匹配（1.38±0.49mm）与匹配（1.14±0.52mm）插件相比，阶跃高度显着更高（=0.015）。外侧象限阶跃在匹配（0.89±0.43mm）和不匹配（1.60±0.78mm）移植物之间存在显着差异（=0.007）。
尽管未匹配的 Wiberg 髌骨骨软骨同种异体移植并未导致软骨下骨表面高度偏差有显着差异，但在外侧象限的周向软骨下骨阶跃高度存在显着差异。使用有限元分析模型的进一步研究将有助于确定软骨下骨表面在这些区域的剪切和压缩力分布中的作用。
鉴于软骨下骨刚度和形态在软骨健康中起作用，软骨下骨一致性可能在移植物存活中起作用。了解这种一致性如何影响软骨力分布将有助于外科医生提高骨软骨同种异体移植的长期成功率。
