Nanno Mitsuhiko, Sawaizumi Takuya, Kodera Norie, Tomori Yuji, Takai Shinro
Department of Orthopaedic Surgery, Nippon Medical School, Musashi Kosugi Hospital.
J Nippon Med Sch. 2015;82(5):220-8. doi: 10.1272/jnms.82.220.
This study aimed to evaluate the kinematics of the flexor pollicis longus tendon (FPL) at the wrist by examining the movement of the FPL on the distal radius during various wrist and finger motions using transverse ultrasound in healthy volunteers.
Forty-eight wrists of 24 asymptomatic volunteers were examined by transverse ultrasound to observe the location of the FPL on the distal radius at 5 wrist positions (neutral, 60° dorsal flexion, 60° palmar flexion, 40° ulnar deviation, and 10° radial deviation) with all 5 fingers in full extension and full flexion, and isolated thumb in full flexion, respectively.
We found that the FPL was situated statistically significantly more ulnodorsally at the wrist dorsal and ulnar deviation positions, more ulnopalmarly at the wrist palmar flexion position, and more radiopalmarly at the wrist radial deviation-position than at the wrist neutral position with all 5 fingers at full extension. Especially, it moved statistically significantly most ulnodorsally at the wrist dorsal flexion position during finger motion. The FPL moved most statistically significantly ulnopalmarly at the wrist palmar flexion position with all 5 fingers in full extension among all wrist positions during finger motion. During finger motion, the wrist dorsal flexion position induced significant displacement of the FPL to the distal radius and compressed it between the flexor tendons and the distal radius. The average distance between the FPL and the volar surface of the distal radius in the palmar-dorsal direction at wrist dorsal flexion position in all fingers at full flexion was 1.9 mm, the smallest among all wrist positions during finger motion.
There is a significant relationship between the transverse movement of the FPL at the distal radius and wrist and finger motions. Our findings indicated that the irritation of the FPL caused by the movement of both the FPL itself and of the flexor digitorum superficialis and profundus is most induced with the wrist in dorsal flexion with all 5 fingers at full flexion compared to other wrist positions during finger motion. This wrist position might be the optimum one at which to evaluate the irritation of the FPL from volar locking plates in patients with distal radius fracture. We believe that our transverse ultrasound results can play a role in the gaining of a better understanding of the kinematics of the FPL. Moreover, they have potential to lead to improved diagnosis of and treatment for fractures of the distal radius and help to minimize the risk of FPL rupture related to volar locking plates.
本研究旨在通过使用横向超声检查健康志愿者在各种腕部和手指运动过程中拇长屈肌腱（FPL）在桡骨远端的运动情况，来评估腕部FPL的运动学。
对24名无症状志愿者的48个腕部进行横向超声检查，以观察在5种腕部位置（中立位、背伸60°、掌屈60°、尺偏40°和桡偏10°）下，当所有5根手指完全伸展和完全屈曲，以及单独拇指完全屈曲时，FPL在桡骨远端的位置。
我们发现，与所有5根手指完全伸展时的腕部中立位相比，在腕部背伸和尺偏位置，FPL在统计学上显著更位于尺背侧；在腕部掌屈位置，FPL更位于尺掌侧；在腕部桡偏位置，FPL更位于桡掌侧。特别是，在手指运动过程中，FPL在腕部背伸位置时在统计学上显著最位于尺背侧。在手指运动过程中的所有腕部位置中，当所有5根手指完全伸展时，FPL在腕部掌屈位置时在统计学上显著最位于尺掌侧。在手指运动过程中，腕部背伸位置会导致FPL向桡骨远端显著移位，并将其挤压在屈肌腱和桡骨远端之间。在所有手指完全屈曲时，腕部背伸位置下FPL与桡骨远端掌侧表面在掌背方向上的平均距离为1.9毫米，是手指运动过程中所有腕部位置中最小的。
FPL在桡骨远端的横向运动与腕部和手指运动之间存在显著关系。我们的研究结果表明，与手指运动过程中的其他腕部位置相比，当腕部背伸且所有5根手指完全屈曲时，FPL自身以及指浅屈肌和指深屈肌的运动对FPL造成的刺激最大。这个腕部位置可能是评估桡骨远端骨折患者掌侧锁定钢板对FPL刺激的最佳位置。我们相信，我们的横向超声检查结果有助于更好地理解FPL的运动学。此外，它们有可能改善桡骨远端骨折的诊断和治疗，并有助于将与掌侧锁定钢板相关的FPL断裂风险降至最低。
