Nuffield Department of Orthopaedics, Rheumatology, and Musculoskeletal Sciences, University of Oxford, Windmill Road, Headington, Oxford OX3 7LD, England. E-mail address for D.W. Murray:
J Bone Joint Surg Am. 2016 Jan 6;98(1):1-8. doi: 10.2106/JBJS.N.00487.
High-volume surgeons attain the best results following unicompartmental knee replacement (UKR), but the exact relationship between caseload and outcome is not clear. It is not known whether this effect is due to patient selection or surgical skill nor whether a similar effect is seen in total knee replacement (TKR). The aim of this study was to quantify the effect of surgical caseload on survival of both TKR and UKR.
This study was based on 459,280 patient records (422,149 TKRs and 37,131 UKRs) from the National Joint Registry for England and Wales. The caseload-outcome relationship was characterized graphically and quantified using regression techniques. Patient selection was compared among high, medium, and low-volume surgeons. Prosthetic survival was compared between UKRs (performed by high, medium, and low-volume surgeons) and matched TKRs.
Caseload affected survival of TKR and, more strongly, of UKR. The revision rate following UKR dropped steeply until the volume reached ten cases per year, plateauing at thirty cases. For surgeons performing fewer than ten UKRs per year, the mean eight-year rate of survival of the UKRs was 87.9% (95% confidence interval [CI] = 86.9% to 88.8%) compared with 92.4% (95% CI = 90.9% to 93.6%) for those who performed thirty UKRs or more per year. Analysis of the TKRs showed a linear decrease in revision rate as caseload increased (hazard ratio [HR] for revision = 0.99 [95% CI = 0.98 to 0.99] for every five-case increase in caseload). Surgeons who performed a lower volume of UKRs tended to operate on younger and healthier patients and were more likely to perform revisions to treat loosening and pain. After matching of patients who had undergone UKR with those who had undergone TKR, the surgeons who performed a high volume of UKRs were found to have an eight-year revision/revision rate similar to that seen after TKR (HR for revision or reoperation = 1.10 [95% CI = 0.99 to 1.22] favoring TKR).
This study confirmed the importance of surgical caseload in determining the survival of UKR and, to a lesser extent, TKR. The reasons for this effect are complex and not fully explained by variables recorded in the National Joint Registry; however, the patient selection and revision threshold of lower-volume surgeons may be a factor. Examination of matched patients in this study demonstrated that high-volume surgeons can achieve revision/reoperation rates similar to those observed following TKR.
在单髁膝关节置换术（UKR）后，高手术量的外科医生能够取得最佳效果，但手术量与结果之间的确切关系尚不清楚。尚不清楚这种效果是由于患者选择还是手术技能所致，也不清楚这种效果是否在全膝关节置换术（TKR）中存在。本研究的目的是定量评估手术量对 TKR 和 UKR 生存率的影响。
本研究基于英格兰和威尔士国家关节登记处的 459280 名患者记录（422149 例 TKR 和 37131 例 UKR）。通过图形和回归技术来描述手术量-结果关系并进行量化。比较高、中、低手术量外科医生之间的患者选择。比较 UKR（由高、中、低手术量外科医生进行）与匹配的 TKR 的假体生存率。
手术量影响 TKR 的生存率，对 UKR 的影响更大。UKR 后的翻修率急剧下降，直到每年达到 10 例，然后稳定在 30 例。对于每年进行少于 10 例 UKR 的外科医生，UKR 的 8 年平均生存率为 87.9%（95%置信区间[CI] = 86.9%至 88.8%），而每年进行 30 例或以上 UKR 的外科医生的生存率为 92.4%（95%CI = 90.9%至 93.6%）。对 TKR 的分析显示，翻修率随着手术量的增加而呈线性下降（每增加 5 例手术，翻修的风险比[HR]为 0.99[95%CI = 0.98 至 0.99]）。手术量较低的外科医生倾向于为年龄较小且健康状况较好的患者进行手术，并且更倾向于进行翻修以治疗松动和疼痛。在 UKR 患者与 TKR 患者匹配后，发现进行大量 UKR 的外科医生的 8 年翻修/再手术率与 TKR 相似（翻修或再次手术的 HR = 1.10[95%CI = 0.99 至 1.22]，TKR 更有利）。
本研究证实了手术量在确定 UKR 和 TKR 生存率方面的重要性，在一定程度上也证实了这一点。这种效果的原因很复杂，无法完全用国家关节登记处记录的变量来解释；但是，低手术量外科医生的患者选择和翻修阈值可能是一个因素。本研究对匹配患者的检查表明，高手术量的外科医生可以达到与 TKR 相似的翻修/再手术率。
