拇指掌指关节绞锁18例临床分析及发病机制的探讨

Clinical analysis and investigation of mechanism of 18 cases with metacarpophalangeal joint locking of the thumb

目的探讨拇指掌指关节绞锁的发病机制,对现有治疗方法做出改良。方法回顾性分析北京积水潭医院2007年3月—2014年10月收治的18例拇指掌指关节绞锁患者的临床资料,其中男17例、女1例,年龄19~41岁,右侧15例、左侧3例。手术治疗4例,根据手术中发现的解剖特征,推断发病机制;保守治疗14例,其中改良复位手法治疗3例,传统复位手法治疗11例。观察患者治疗后拇指掌指关节的主、被动活动度、疼痛、稳定性以及和关节绞锁是否复发等。结果(1)4例手术治疗患者术中观察到桡侧籽骨近侧缘撞击掌骨头关节面导致出现软骨缺损,籽骨嵌于软骨缺损内致使拇指掌指关节绞锁。在近节指骨基底处部分松解拇短展肌和拇短屈肌腱止点,可以很容易地解除关节绞锁。术后随访3~6个月,所有患者拇指掌指关节未见不稳定和疼痛,未见绞锁复发。患者术前拇指掌指关节主动活动度平均为-31.8°^-19.3°,被动活动度平均为-32.5°~30°;术后关节主、被动活动度一致,平均为-3.8°~52.5°;患者对手术疗效的主观评价均满意。(2)14例保守治疗患者均复位成功,其中改良复位手法3例,传统复位手法11例。复位前拇指掌指关节活动度平均为-28.6°^-15.2°,被动活动度为-30.4°~26.5°;复位后关节主、被动活动度一致,平均活动度为-15.8°~47.5°。随访6~8周,末次随访双侧拇指掌指关节活动度一致,未见关节不稳定和疼痛,未见绞锁复发。结论拇指掌指关节绞锁的发病机制为拇指过伸时桡侧籽骨向远端和桡侧移位,其近侧缘在掌骨头关节面上刻划出一沟槽状软骨缺损,在拇短展肌和拇短屈肌腱的张力作用下,籽骨嵌于软骨缺损中而导致关节发生绞锁。根据这一损伤机制,改良复位手法可被用于治疗拇指掌指关节绞锁。

Objective To study the mechanism of metacarpophalangeal joint locking of the thumb,and modify the current treatment.Methods Eighteen patients with metacarpophalangeal joint(MCPJ)locking of the thumb were studied from 2007 to 2014 in Beijing Jishuitan Hospital.There were 17 males and 1 female with age of 19-41 years old,and 15 patients were on the right side,3 patients were on the left side.Four patients were treated surgically.According to the anatomical characteristics found in the operation,the mechanism was deduced,Fourteen patients were treated conservatively,including 3 patients treated with modified reduction method and 11 patients treated with traditional reduction method.The patients were followed up to observe the active and passive range of motion(ROM),pain,stability of metacarpophalangeal joint of the thumb,and recurrence.Results(1)During surgery,it was found that the radial sesamoid was seated in a cartilage defect on the volar aspect of the metacarpal head.It appeared that the defect was created by the proximal edge of sesamoid.When the abductor pollicis brevis(APB)and flexor pollicis brevis(FPB)muscles were partially detached from their insertion at the base of the proximal phalanx,the locking could be successfully released.All patients satisfied the recovery of the function.No recurrence of the locking was found during a follow-up of 3 to 6 months.All patients obtained the full active and passive ROM for their MCPJ with neither pain nor instability.Before operation,the mean active and passive ROM of the thumb MCPJ was from-31.8°to-19.3°and from-32.5°to-30°,respectively.The mean ROM of the joint was from-3.8°to 52.5°postoperatively.Active hyperextension of the first metacarpophalangeal joint was restricted after operation.The results of the treatment were assessed as satisfactory by all patients.(2)Fourteen cases were treated with conservative method successfully.Before reduction,the mean active and passive ROM of the thumb MCPJ was from-28.6°to 15.2°and from-30.4°to 26.5°,respectively.All patients obtained the full active and passive ROM for their MCPJ with neither pain nor instability.The mean ROM of the joint was form-15.8°to 47.5°after reduction.No recurrence of the locking was found during a follow-uo of 6 to 8 weeks.Conclusions The pathogenesis of thumb metacarpophalangeal joint dislocation is that the radial sesamoid is displaced distally and radially when the thumb is overextended.A groove-shaped cartilage defect on the articular surface of the metacarpal head is carved by the proximal edge of the radial sesamoid.Under the tension of the APB and FPB tendons,the sesamoid is embedded in the cartilage defect,thereby causing locking of the joint.Based on this mechanism,a modified reduction method can be used to treat MCPJ locking of the thumb.