Oxford Orthopaedic Engineering Centre, Nuffield Department of Orthopaedics, Rheumatology, and Musculoskeletal Sciences, Botnar Research Centre, University of Oxford, Oxford, UK.
Indiana University School of Medicine, Indianapolis, Indiana, USA.
Knee Surg Sports Traumatol Arthrosc. 2024 Mar;32(3):704-712. doi: 10.1002/ksa.12092. Epub 2024 Feb 28.
Cementless Oxford unicompartmental knee replacement (OUKR) is associated with less pain than cemented OUKR 5 years postoperatively. This may be due to improved fixation at the tibial wall, which transmits tension and reduces stress in the bone below the tibial component. This study compares tibial wall fixation with three different types of fixation: cemented, cementless with hydroxyapatite (HA) and cementless with a microporous titanium coat and HA (HA + MPC).
Three consecutive cohorts were identified (n = 221 cemented in 2005-2007, n = 118 HA in 2014-2015, n = 125 HA + MPC in 2016-2017). Analysis was performed on anterior-posterior radiographs aligned on the tibial component taken 1-2 years postoperatively. Aligned radiographs are needed to see narrow radiolucencies adjacent to the wall. Alignment was assessed with rotation ratio (RR = wall width/internal wall height). Perfect RR is 0.3, and a maximum threshold of 0.5 was used. Quality of fixation to the wall was assessed with fixation ratio (FR = bone wall contact height/total wall height). Notable radiographic features at the tibial wall were also recorded.
A total of 33 knees with cement, 37 knees with cementless with HA and 57 knees cementless with HA + MPC had adequately aligned radiographs. Fixation was significantly better with HA compared with cement (55% vs. 25%, p = 0.0016). The microporous coat further improved fixation (81% vs. 55%, p < 0.0001). FR > 80% was achieved in 3% of the cemented implants, 32% of HA and 68% of HA + MPC. In cementless cohorts, features suggestive of a layer of bone that had delaminated from the wall were seen in 8 (22%) HA and 3 (5%) HA + MPC knees.
Radiographic tibial wall fixation in OUKR is poor with cement. It improves with an HA coating and improves further with an intermediary MPC. Improved tibial wall fixation may explain the lower levels of pain observed with cementless rather than cemented fixation described in the literature, but further clinical correlation is needed.
Level III, retrospective cohort study.
与骨水泥固定牛津单髁膝关节置换术（OUKR）相比，非骨水泥固定 OUKR 在术后 5 年时疼痛程度更低。这可能是由于胫骨壁的固定得到改善，从而传递张力并减少胫骨部件下方骨的应力。本研究比较了三种不同固定方式（骨水泥固定、含羟基磷灰石（HA）的非骨水泥固定和含微孔钛涂层和 HA（HA+MPC）的非骨水泥固定）的胫骨壁固定情况。
确定了三个连续队列（2005-2007 年的 221 例骨水泥固定、2014-2015 年的 118 例 HA 固定、2016-2017 年的 125 例 HA+MPC 固定）。在术后 1-2 年对胫骨组件上的前后位 X 射线进行分析，这些 X 射线经过对齐。需要对齐的 X 射线才能看到胫骨壁附近的狭窄透光区。通过旋转比（RR=壁宽/内壁高度）评估对齐情况。理想的 RR 为 0.3，最大阈值为 0.5。通过固定比（FR=骨壁接触高度/总壁高度）评估对壁的固定质量。还记录了胫骨壁上的明显放射学特征。
共有 33 个膝关节使用骨水泥、37 个膝关节使用含 HA 的非骨水泥和 57 个膝关节使用含 HA+MPC 的非骨水泥进行了适当的 X 射线对齐。与骨水泥相比，HA 的固定明显更好（55%对 25%，p=0.0016）。微孔涂层进一步改善了固定（81%对 55%，p<0.0001）。在骨水泥固定组中，只有 3%的植入物达到了 FR>80%，HA 组为 32%，HA+MPC 组为 68%。在非骨水泥组中，在 8（22%）例 HA 和 3（5%）例 HA+MPC 膝关节中观察到提示骨壁有一层已分层的骨的特征。
在 OUKR 中，胫骨壁的骨水泥固定效果不佳。使用 HA 涂层可改善固定效果，使用中间 MPC 可进一步改善固定效果。胫骨壁固定的改善可能解释了文献中观察到的非骨水泥固定而非骨水泥固定的疼痛水平较低的情况，但需要进一步的临床相关性研究。
三级，回顾性队列研究。
