Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences University of Oxford, Nuffield Orthopaedic Centre, Oxford, OX3 7LD,, UK.
Musculoskeletal Research Unit, Level 1 Learning and Research Building, University of Bristol, Southmead Hospital, Bristol, BS10 5NB,, UK.
J Orthop Surg Res. 2020 Jan 31;15(1):35. doi: 10.1186/s13018-020-1566-2.
Osteoporosis and osteopenia are conditions characterised by reduced bone mineral density (BMD). There is concern that bone with reduced BMD may not provide sufficient fixation for cementless components which primarily rely on the quality of surrounding bone. The aim of our study was to report the midterm clinical outcomes of patients with reduced BMD undergoing cementless unicompartmental knee replacements (UKR). Our hypothesis was that there would be no difference in outcome between patients with normal bone and those with reduced BMD.
From a prospective cohort of 70 patients undergoing cementless UKR surgery, patients were categorised into normal (n = 20), osteopenic (n = 38) and osteoporotic groups (n = 12) based on their central dual-energy X-ray absorptiometry (DEXA) scans according to the World Health Organization criteria. Patients were followed up by independent research physiotherapists and outcome scores; Oxford Knee Score (OKS), Tegner score, American Knee Society Score Functional (AKSS-F) and Objective (AKSS-O) were recorded preoperatively and at a mean of 4 years postoperatively. The prevalence of reoperations, revisions and mortality was also recorded at a mean of 5 years postoperatively.
There were no significant differences in the midterm postoperative OKS (P = 0.83), Tegner score (P = 0.17) and AKSS-O (P = 0.67). However, the AKSS-F was significantly higher (P = 0.04) in normal (90, IQR 37.5) compared to osteoporotic (65, IQR 35) groups. There were no significant differences (P = 0.82) between normal and osteopenic bone (80, IQR 35). The revision prevalence was 5%, 2.6% and 0% in the normal, osteopenic and osteoporotic groups respectively. The reoperation prevalence was 5%, 7.9% and 0% respectively. There were no deaths in any group related to the implant.
We found that patients with reduced BMD could safely undergo cementless UKR surgery and have similar clinical outcomes to those with normal BMD. However, larger studies with longer follow-up are needed to confirm our findings and ensure that cementless fixation is safe in patients with reduced BMD.
骨质疏松症和骨量减少症的特征是骨密度降低（BMD）。人们担心，骨密度降低的骨骼可能无法为主要依赖周围骨骼质量的非骨水泥部件提供足够的固定。我们研究的目的是报告接受非骨水泥单髁膝关节置换术（UKR）治疗的骨密度降低患者的中期临床结果。我们的假设是，正常骨患者和骨密度降低患者的结果没有差异。
从接受非骨水泥 UKR 手术的 70 名患者的前瞻性队列中，根据世界卫生组织标准，根据中央双能 X 线吸收法（DEXA）扫描将患者分为正常组（n=20）、骨质疏松组（n=38）和骨质疏松组（n=12）。由独立的研究理疗师对患者进行随访，并记录术前和平均 4 年后的牛津膝关节评分（OKS）、Tegner 评分、美国膝关节协会评分功能（AKSS-F）和客观（AKSS-O）。还记录了平均 5 年后的再手术、翻修和死亡率的发生率。
在中期术后 OKS（P=0.83）、Tegner 评分（P=0.17）和 AKSS-O（P=0.67）方面，无显著差异。然而，正常组（90，IQR37.5）的 AKSS-F 明显高于骨质疏松组（65，IQR35）（P=0.04）。正常骨与骨质疏松骨（80，IQR35）之间无显著差异（P=0.82）。正常、骨质疏松和骨质疏松组的翻修发生率分别为 5%、2.6%和 0%。再手术的发生率分别为 5%、7.9%和 0%。任何组均无与植入物相关的死亡。
我们发现，骨密度降低的患者可以安全地接受非骨水泥 UKR 手术，并且与骨密度正常的患者具有相似的临床结果。然而，需要更大规模的研究和更长时间的随访来证实我们的发现，并确保非骨水泥固定在骨密度降低的患者中是安全的。
