膝骨关节炎患者膝痛和膝冷与髌下脂肪垫神经支配病理特征的相关性分析

Correlation analysis of knee pain and coldness in osteoarthritis between patients'complaints and the pathological characteristics of infrapatellar fat pad innervation

目的探讨膝骨关节炎(KOA)患者髌下脂肪垫神经支配的病理特征及其与患者膝关节痛、冷感觉的相关性。方法前瞻性非随机对照研究。纳入2022年2—12月中国康复研究中心北京博爱医院29例(29膝)KOA患者为KOA组,纳入同期8例(8膝)膝关节或膝关节周围组织急性创伤的非KOA患者为对照组。KOA组男8例、女21例,年龄61~95[70.0(64.5,76.5)]岁,均行初次全膝关节置换术治疗,对照组男6例、女2例,年龄30~84[61.0(30.5,81.0)]岁,接受开放手术或关节镜手术治疗。术前采用疼痛视觉模拟评分法(VAS)评分、西安大略和麦克马斯特大学骨关节炎指数(WOMAC)、膝关节协会评分(KSS)和膝冷评分定量评价KOA患者的膝关节疼痛、寒冷程度,并根据Kellgren-Lawrence(K-L)影像分级系统对KOA患者进行K-L分级。采用免疫荧光法检测2组患者髌下脂肪垫内降钙素基因相关肽(CGRP)阳性感觉神经和酪氨酸羟化酶(TH)阳性交感神经的密度,采用酶联免疫吸附试验(ELISA)检测KOA组患者髌下脂肪垫内CGRP含量。观察指标:(1)比较2组患者的性别、年龄、侧别、体质量指数(BMI)等基线资料。(2)比较2组患者髌下脂肪垫中免疫荧光检测CGRP阳性感觉神经和TH阳性交感神经密度的差异,(3)比较不同K-L分级患者免疫荧光检测CGRP阳性感觉神经和TH阳性交感神经密度的差异,(4)分析CGRP阳性感觉神经、TH阳性交感神经及CGRP含量与VAS评分、WOMAC、KSS、膝冷评分的相关性,(5)分析膝冷评分与K-L分级、VAS评分和WOMAC疼痛分量表的相关性。结果(1)2组患者的年龄、侧别、BMI比较,差异均无统计学意义(P值均>0.05),性别差异有统计学意义(P=0.035)。(2)KOA组CGRP阳性感觉神经密度[17.65(5.88,23.53)fibers/mm^(2)]高于对照组[2.94(0.00,16.18)fibers/mm^(2)],TH阳性交感神经密度[11.76(0.00,17.65)fibers/mm^(2)]低于对照组[20.59(13.23,29.41)fibers/mm^(2)],差异均有统计学意义(Z=2.16、2.48,P值均<0.05)。(3)29例KOA患者中K-L 3级15例、4级14例。K-L 4级KOA患者CGRP阳性感觉神经密度[(25.21±13.73)fibers/mm^(2)]高于K-L 3级KOA患者[(9.80±8.52)fibers/mm^(2)],差异有统计学意义(t=3.66,P=0.001),K-L 3级和4级KOA患者TH阳性交感神经密度分别为[11.76(5.88,17.65)fibers/mm^(2)]和[8.82(0.00,23.53)fibers/mm^(2)],差异无统计学意义(Z=0.27,P=0.813)。(4)CGRP含量为7.18~18.50(11.50±2.66)μg/L,与WOMAC疼痛分量表中夜间睡眠时疼痛呈正相关(r=0.444,P=0.044),与膝冷评分呈正相关(r=0.500,P=0.021),TH阳性交感神经密度与VAS评分呈负相关(r=-0.438,P=0.047),与WOMAC疼痛分量表中夜间睡眠时疼痛呈负相关(r=-0.523,P=0.015)、与膝冷评分呈负相关(r=-0.457,P=0.037)。(5)膝冷评分与K-L分级、VAS评分、WOMAC疼痛分量表之间均无相关性(P值均>0.05)。结论KOA患者髌下脂肪垫内CGRP含量增高会加重其膝关节痛、冷感觉,而TH阳性交感神经密度增高会减轻其膝关节痛、冷感觉。尽管未发现CGRP阳性感觉神经密度与膝关节痛、冷感觉之间的关系,但是CGRP含量与膝关节痛冷感之间存在一定的相关性。

Objective This study aimed to investigate the correlation between the pathological characteristics of infrapatellar fat pad innervation in knee osteoarthritis(KOA)with knee pain and coldness.Methods A prospective non-randomized controlled study was conducted.From February 2022 to December 2022,29 KOA patients(29 knees)in Beijing Boai Hospital,China Rehabilitation Research Center were enrolled in the KOA group,and 8 non-KOA patients(8 knees)with acute trauma to the knee joint or surrounding tissues were recruited as the control group.The KOA group included 8 males and 21 females,who were aged 61-95(70.0[64.5,76.5])and underwent primary total knee arthroplasty.The control group comprised 6 males and 2 females,who were aged 30-84(61.0[30.5,81.0])and underwent open surgery or arthroscopic surgery.The pain Visual Analogue Scale(VAS),the Western Ontario and McMaster Universities Osteoarthritis index(WOMAC),the Knee Society score(KSS),and the cold knee score were all used to quantitatively assess the severity of knee pain and coldness in the KOA patients prior to surgery.KOA patients were rated according to the Kellgren-Lawrence(K-L)radiographic grading system.Immunofluorescence was used to identify the density of sensory(calcitonin gene-related peptide[CGRP]as a marker)and sympathetic(tyrosine hydroxylase[TH]as a marker)nerves in the infrapatellar fat pad of two groups of patients.Enzyme-linked immunosorbent assay was used to measure the content of CGRP in the infrapatellar fat pad of patients in the KOA group.The following observation indicators were investigated:(1)The baseline data such as gender,age,side,and body mass index(BMI)of patients in two groups were compared.(2)The density differences of CGRP-positive sensory nerves and TH-positive sympathetic nerves in the infrapatellar fat pad between the two groups were compared.(3)The density of CGRP-positive sensory nerves and TH-positive sympathetic nerves in patients with different K-L grades was compared.(4)The correlation among CGRP-positive sensory nerves,TH-positive sympathetic nerves,and CGRP content with VAS,WOMAC,KSS,and cold knee scores was analyzed.(5)The correlation between cold knee scores with K-L grading,VAS,and WOMAC pain subscale was explored.Results(1)No significant difference in age,side,and BMI was observed between the two groups(all P values>0.05).The gender difference was statistically significant(P=0.035).(2)The density of CGRP-positive sensory nerve(17.65[5.88,23.53]fibers/mm^(2))in the KOA group was higher than that in the control group(2.94[0.00,16.18]fibers/mm').Meanwhile,the density of TH-positive sympathetic nerve(11.76[0.00,17.65]fibers/mm^(2))was lower than that in the control group(20.59[13.23,29.41]fibers/mm^(2)).Notably,the differences were statistically significant(Z=2.16,2.48,all P values<0.05).(3)A total of 15 patients of K-L 3 grade and 14 patients of K-L 4 grade were found in 29 KOA patients.The density of CGRP-positive sensory nerve in K-L 4 grade KOA patients([25.21±13.73]fibers/mm^(2))was higher than that in K-L 3 grade KOA patients([9.80+8.52]fibers/mm^(2)),and the differences were statistically significant(t=3.66,P=0.001).The densities of TH-positive sympathetic nerve in K-L 3 and K-L 4 grade KOA patients were(11.76[5.88,17.65]fibers/mm^(2))and(8.82[0.00,23.53]fibers/mm^(2)),respectively,with no statistically significant difference(Z=0.27,P=0.813).(4)CGRP content was 7.18-18.50(11.50±2.66)μg/L,which was positively correlated with pain during sleep at night on the WOMAC(r=0.444,P=0.044)and positively correlated with the cold knee scores(r=0.500,P=0.021).The density of TH-positive sensory nerve was negatively correlated with VAS(r=-0.438,P=0.047),negatively correlated with pain during sleep at night on the WOMAC(r=-0.523,P=0.015),and negatively correlated with the cold knee scores(r=-0.457,P=0.037).(5)No correlation existed between the cold knee scores and K-L grading,VAS,and WOMAC pain subscale(all P values>0.05).Conclusion An increase in CGRP content in the infrapatellar fat pad of patients with KOA can exacerbate knee pain and coldness.Meanwhile,an increase in the density of TH-positive sympathetic nerve can alleviate knee pain and coldness.Although no correlation was found between the density of CGRP-positive sensory nerve and knee pain and coldness,there is a certain correlation between CGRP and knee pain and coldness.