Elias John J, Farrow Lutul D, Lartey Richard, Ok Ahmet Hakan, Li Mei, Yang Mingrui, Winalski Carl S, Li Xiaojuan
Cleveland Clinic Akron General, Akron, Ohio, USA.
Cleveland Clinic, Cleveland, Ohio, USA.
Orthop J Sports Med. 2025 May 20;13(5):23259671251334634. doi: 10.1177/23259671251334634. eCollection 2025 May.
Elevated body mass index (BMI) is a primary factor contributing to osteoarthritis of the knee, but data are lacking on the relationship between BMI and cartilage properties shortly after a traumatic injury.
PURPOSE/HYPOTHESIS: The purpose of the study was to relate BMI to patellofemoral cartilage properties after a patellar dislocation, using magnetic resonance imaging-based T1ρ relaxation times to assess cartilage. It was hypothesized that high BMI is correlated with long patellofemoral cartilage T1ρ relaxation times, indicating cartilage degradation, in both control knees and knees after patellar dislocation.
Cross-sectional study; Level of evidence, 3.
T1ρ relaxation time mapping was performed for underweight to obese (BMI < 40 kg/m) patients after a first-time patellar dislocation (n = 26; 19.8 ± 6.7 years old; 46 ± 36 days since dislocation), after multiple dislocations (n = 15; 18.4 ± 5.1 years old; 63 ± 33 days since most recent dislocation), and for healthy controls (n = 20; 20.1 ± 6.6 years old). For medial, lateral, and central regions of patellofemoral cartilage, mean T1ρ relaxation times were correlated against BMI. Statistical significance was set at < .05.
For the control group, long T1ρ relaxation times were significantly correlated with high BMI for every region of patellofemoral cartilage except the lateral patella ( < .025; = 0.26-0.63). On the contrary, for the first-time and multiple dislocations groups, long T1ρ relaxation times were significantly correlated with low BMI ( < .05; = 0.24-0.50) for the medial patella (multiple dislocations only), central patella, lateral patella, medial trochlear groove (first-time dislocation only), central trochlear groove (first-time dislocation only), and lateral trochlear groove (first-time dislocation only).
Long patellofemoral cartilage T1ρ relaxation times were related to high BMI for healthy knees, but unexpectedly related to low BMI after patellar dislocation. The results do not indicate a heightened risk of progressive cartilage degradation to osteoarthritis for overweight and obese patients immediately after patellar dislocation. For patients at a healthy weight and underweight, the traumatic injury is associated with early cartilage degradation, which could potentially initiate progressive degradation to posttraumatic osteoarthritis.
体重指数（BMI）升高是导致膝关节骨关节炎的主要因素，但关于创伤性损伤后不久BMI与软骨特性之间的关系，目前尚缺乏相关数据。
目的/假设：本研究的目的是通过基于磁共振成像的T1ρ弛豫时间来评估软骨，以探讨BMI与髌骨脱位后髌股关节软骨特性之间的关系。研究假设为，在对照组膝关节和髌骨脱位后的膝关节中，高BMI与较长的髌股关节软骨T1ρ弛豫时间相关，提示软骨退变。
横断面研究；证据等级为3级。
对首次髌骨脱位（n = 26；年龄19.8±6.7岁；脱位后46±36天）、多次脱位（n = 15；年龄18.4±5.1岁；距最近一次脱位63±33天）的体重过轻至肥胖（BMI < 40 kg/m²）患者以及健康对照组（n = 20；年龄20.1±6.6岁）进行T1ρ弛豫时间成像。对于髌股关节软骨的内侧、外侧和中央区域，将平均T1ρ弛豫时间与BMI进行相关性分析。设定统计学显著性水平为P <.05。
在对照组中，除髌骨外侧区域外，髌股关节软骨各区域的长T1ρ弛豫时间均与高BMI显著相关（P <.025；r = 0.26 - 0.63）。相反，在首次脱位组和多次脱位组中，髌骨内侧（仅多次脱位）、髌骨中央、髌骨外侧、内侧滑车沟（仅首次脱位）、中央滑车沟（仅首次脱位）和外侧滑车沟（仅首次脱位）的长T1ρ弛豫时间与低BMI显著相关（P <.05；r = 0.24 - 0.50）。
对于健康膝关节，髌股关节软骨较长的T1ρ弛豫时间与高BMI相关，但在髌骨脱位后却意外地与低BMI相关。这些结果并未表明超重和肥胖患者在髌骨脱位后立即发生软骨渐进性退变至骨关节炎的风险增加。对于体重正常和体重过轻的患者，创伤性损伤与早期软骨退变相关，这可能会引发向创伤后骨关节炎的渐进性退变。
