An Anatomic Study Of The Effect Of Froximal Interphalangeal Point Joint (PIPJ) Motion On The Tension Of The Extensor Tendon In Zone ?-?

Objectives Through the anatomy study in zone ?-? of extensor tendon in fresh adult specimen of the upper extremity,to observe the effect of interphalangeal joint activities in this area of the extensor tendon and to provide the anatomical basis for the fixed position in the treatment of extensor tendon injury.in zone ?-?.Methods 1 Anatomical study: The maximum passive flexion angle of 2nd-5th distal interphalangeal joint(DIPJ)from 16 fresh embalmed cadaver hands were measured with the proximal interphalangeal joint(PIPJ)in flexion 0°,45°and 90° position.The above measurements were repeated in three cases,which were to remove the dorsal skin,section the oblique retinacula ligament,and section the extensor tendon.The extensor tendon area was exposed in zone ?-?,and then be sectioned to make a mallet finger model.A Kirsches wire was pierced through the phalanx axis vertically in the middle phalanx neck level as a reference.A mark was made in the extensor tendon for the use of measuring the tendon gliding distance.The broadest gaps between the tendon edges and the tendon gliding distances were measured when the proximal interphalangeal joint(PIPJ)was flexed extension 0° to flexion 90° position.2 Clinical application: In our department from June 2013 to March 2016,70 patients with fresh mallet fingers were treated with expectant treatment.Among them,47 cases were tendinous mallet fingers,and the other was bony mallet finger(n=23).The fixed position was the extension of the metacarpophalangeal joint(MPJ),the flexion of the proximal interphalangeal joint(PIPJ)was 45°,and the distal interphalangeal joint(DIPJ)was extended to a depth of about 5°,with a fixed time of 6 weeks.The functional exercise began after 6 weeks treatment,and the patients were reviewed after 10 weeks and 14 weeks.The determination of the distal interphalangeal joint(DIPJ)flexion angle and the stretching angle was done in review.The therapeutic effect was evaluated by TAM scoring system.Results 1 Anatomical study: Compared with the results of intact finger,there was no significant difference in the maximum flexion angle of distal interphalangeal joint(DIPJ)between the removal of dorsal skin and sectioned the oblique retinacula ligament(P>0.05);When the extensor tendon was cut off,the passive flexion angle of the distal interphalangeal joint was significantly different(P<0.05),and do not follow the changes of the proximal interphalangeal joint.The maximum passive flexion angle of the distal interphalangeal joint(DIPJ)increased about 12% when the proximal interphalangeal joint(PIPJ)was flexed from extension 0° to flexion 90° position.The gap between the extensor tendon edges in zone II was 0.43mm(SD 0.09)when the proximal interphalangeal joint(PIPJ)was in extension 0° position.The proximal side of gap slipped to the distal side when the proximal interphalangeal joint(PIPJ)was flexed to 90° and the slipping distance was 0.76mm(SD 0.10).2 Clinical application: After 14 weeks of expectant treatment,all the 70 patients were reviewed,and the stretching angle of distal interphalangeal joints were markedly improved.The pretherapy stretching angle was 40.49° and the post-treatment was 2.95°.At the end of the review,according to the TAM evaluation,39 cases were excellent,good in 25 cases,fair in 4 cases and poor in 2 cases.The excellent and good rate was about 91.4%.Due to the distal interphalangeal joint swelling and compression pain,4 patients adjusted the orthosis and continue treatment after symptoms disappear.3 patients with orthosis broken were timely reviewed and replaced the orthosis in the treatment period.2 patients had no obvious improvement after treatment,and the surgical treatment was done after communication.Conclusions The extensor tendon is the main influencing factor in the linkage of the proximal interphalangeal joints and distal interphalangeal joints.When the proximal interphalangeal joint(PIPJ)is flexed,the intermediate tendon is pulled to the distal end and the two lateral tendon is moved toward the distal end,while the lateral tendon of the two side slips to the side of the joint.The extensor tendon was relaxed in zone ?-?,and the extensor tendon tension was the lowest.In the clinical treatment of extensor tendon injury and related diseases in zone ?-?,according to the anatomical characteristics of extensor tendon of the finger,can effectively reduce the tension of this area,and combined with rehabilitation exercise,can achieve ideal curative effect.