V. Vestergaard, The Harris Orthopaedics Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital, Boston, MA, USA.
V. Vestergaard, K. Borbjerg Hare, Department of Orthopaedic Surgery, Slagelse Hospital, Slagelse, Denmark.
Clin Orthop Relat Res. 2020 Sep;478(9):2036-2044. doi: 10.1097/CORR.0000000000001099.
Knee fractures may lead to post-traumatic knee osteoarthritis and subsequent TKA in some patients. However, absolute risk estimates and risk factors for TKA in patients with knee fractures compared with those of the general population remain largely unknown. Such knowledge would help establish the treatment burden and direct patient counseling after a knee fracture is sustained.
QUESTIONS/PURPOSES: (1) What is the short-term risk of TKA after knee fracture? (2) What is the long-term risk of TKA after knee fracture? (3) What are the risk factors for TKA in patients with knee fractures?
A nationwide 20-year, matched-case comparison cohort study of prospectively collected data from the Danish National Patient Registry included all patients at least 15 years old with International Classification of Diseases, 10th revision codes DS724, DS820, or DS821 (knee fractures) on the date their knee fracture was registered. Each patient with a knee fracture was matched (by sex and age) to five people without knee fractures from the general Danish population on the date the knee fracture patient's knee fracture was registered (population controls). Patients with knee fractures and people in the population control group were followed from the date the knee fracture patient's knee fracture was registered to the date of TKA, amputation, knee fusion, emigration, death, or end of follow-up in April 2018. TKA risks for patients with knee fractures versus those for population controls and TKA risk factors in patients with knee fractures were estimated using hazard ratios (HRs) with 95% CIs. A total of 48,791 patients with knee fractures (median age 58 years [interquartile range 41-73]; 58% were female) were matched to 263,593 people in the population control group.
The HR for TKA in patients with knee fractures compared with population controls was 3.74 (95% CI 3.44 to 4.07; p < 0.01) in the first 3 years after knee fracture. Among knee fracture patients, the risk of undergoing TKA was 2% (967 of 48,791) compared with 0.5% (1280 of 263,593) of people in the population control group. After the first 3 years, the HR was 1.59 (95% CI 1.46 to 1.71) and the number of patients with knee fractures with TKA events divided by the number at risk was 2% (849 of 36,272), compared with 1% (2395 of 180,418) of population controls. During the 20-year study period, 4% of patients with knee fractures underwent TKA compared with 1% of population controls. Risk factors for TKA in patients with knee fractures were: primary knee osteoarthritis (OA) versus no primary knee OA (HR 9.57 [95% CI 5.39 to 16.98]), surgical treatment with external fixation versus open reduction and internal fixation and reduction only (HR 1.92 [95 % CI 1.01 to 3.66]), proximal tibia fracture versus patellar fracture (HR 1.75 [95 % CI 1.30 to 2.36]), and distal femur fracture versus patellar fracture (HR 1.68 [95 % CI 1.08 to 2.64]). Surgical treatment of knee fractures was also a risk factor for TKA. The HRs for TKA in patients with knee fractures who were surgically treated versus those who were treated non-surgically were 2.05 (95% CI 1.83 to 2.30) in the first 5 years after knee fracture and 1.19 (95% CI 1.01 to 1.41) after 5 years.
Patients with knee fractures have a 3.7 times greater risk of TKA in the first 3 years after knee fracture, and the risk remains 1.6 times greater after 3 years and throughout their lifetimes. Primary knee OA, surgical treatment of knee fractures, external fixation, proximal tibia fractures, and distal femur fractures are TKA risk factors. These risk estimates and risk factors highlight the treatment burden of knee fractures, building a foundation for future studies to further counsel patients on their risk of undergoing TKA based on patient-, fracture-, and treatment-specific factors.
Level III, prognostic study.
膝关节骨折可能导致一些患者发生创伤后膝关节骨关节炎和随后的全膝关节置换术（TKA）。然而，与普通人群相比，膝关节骨折患者发生 TKA 的绝对风险估计和风险因素在很大程度上仍不清楚。这种知识将有助于确定治疗负担，并在膝关节骨折发生后直接为患者提供咨询。
问题/目的：（1）膝关节骨折后 TKA 的短期风险是多少？（2）膝关节骨折后 TKA 的长期风险是多少？（3）膝关节骨折患者发生 TKA 的风险因素有哪些？
一项全国范围内的 20 年、匹配病例对照队列研究，使用前瞻性收集的丹麦国家患者注册中心的数据，包括至少 15 岁的患者，这些患者的国际疾病分类第 10 版代码为 DS724、DS820 或 DS821（膝关节骨折），并在其膝关节骨折登记日期当天进行登记。每一位膝关节骨折患者都与普通丹麦人群中在膝关节骨折患者登记日当天性别和年龄相匹配的五人进行匹配（人群对照）。膝关节骨折患者和人群对照组的患者从膝关节骨折患者的膝关节骨折登记日期开始，随访至 TKA、截肢、膝关节融合、移民、死亡或 2018 年 4 月随访结束。使用风险比（HR）和 95%置信区间（CI）来估计膝关节骨折患者与人群对照组相比的 TKA 风险，以及膝关节骨折患者的 TKA 风险因素。共有 48791 名膝关节骨折患者（中位年龄 58 岁[四分位间距 41-73]；58%为女性）与人群对照组的 263593 人相匹配。
膝关节骨折患者与人群对照组相比，TKA 的 HR 在膝关节骨折后 3 年内为 3.74（95%CI 3.44-4.07；p<0.01）。在膝关节骨折患者中，接受 TKA 的风险为 2%（48791 例中的 967 例），而人群对照组中为 0.5%（263593 例中的 1280 例）。在 3 年后，HR 为 1.59（95%CI 1.46-1.71），膝关节骨折患者发生 TKA 事件的人数与风险人数之比为 2%（36272 例中的 849 例），而人群对照组为 1%（180418 例中的 2395 例）。在 20 年的研究期间，4%的膝关节骨折患者接受了 TKA，而人群对照组为 1%。膝关节骨折患者发生 TKA 的风险因素为：原发性膝关节骨关节炎（OA）与无原发性膝关节 OA（HR 9.57[95%CI 5.39-16.98]）、外固定与切开复位内固定和复位相比（HR 1.92[95%CI 1.01-3.66]）、胫骨近端骨折与髌骨骨折（HR 1.75[95%CI 1.30-2.36]）、股骨远端骨折与髌骨骨折（HR 1.68[95%CI 1.08-2.64]）。膝关节骨折的手术治疗也是 TKA 的一个风险因素。与非手术治疗相比，膝关节骨折患者接受手术治疗的患者发生 TKA 的 HR 分别为：膝关节骨折后 5 年内为 2.05（95%CI 1.83-2.30），5 年后为 1.19（95%CI 1.01-1.41）。
膝关节骨折患者在膝关节骨折后 3 年内接受 TKA 的风险增加 3.7 倍，3 年后及终身风险仍增加 1.6 倍。原发性膝关节 OA、膝关节骨折的手术治疗、外固定、胫骨近端骨折和股骨远端骨折是 TKA 的风险因素。这些风险估计和风险因素突出了膝关节骨折的治疗负担，为未来的研究奠定了基础，以便根据患者、骨折和治疗的具体因素，进一步为患者提供接受 TKA 的风险咨询。
III 级，预后研究。
