The Clinical Study On Surgical Treatment Of Chronic Mallet Finger Deformity Repaired By Palmaris Longus Tendon-flap Graft

Mallet finger is a deformity character with the flexion of DIPjoint because the anatomical continuity of the terminal extensorapparatus is destroyed, and DIP joint loses the function of activeextension. Because flexor tendon is dominant, extension lag is notbe observed by the patient, all those factors induce chronic malletfinger deformity. The deformity is a frequently-occurring disease,and many surgical treatments were reported, but there is not asatisfied final result. To investigate a reliable procedure of surgicaltreatment for chronic mallet finger deformity, we designed andapplied palmaris longus tendon-flap graft to restore the anatomicalconstruction and biomechanical balance of terminal extensorapparatus to 80 cases with chronic mallet finger deformity in past14 years.Methods and Results: under brachial plexus nerve block oranesthesia, a "ㄣ" shape incision is operate on the dorsal skin ofDIP joint, operating and reveal proximal and distal end andremoving hyperplastic cicatricial tissues. A laterigrade hole isdrilled by a miniature drill, and cut a piece of palmaris longustendon-flap(4.0～5.0 ㎝×0.3～0.5 ㎝) with paratenon, and guide theflap to the hole. A Kirschner wire(ф0.8 ㎜)is used to fix the DIPjoint, then adjust the tensity of graft tendon-flap, make it as anisosceles triangle, 0/3 and 0/5 nylon suturalis are used to mattresssuture the tendon-flap and normal tendon, meanwhile, recovery theparatenon. Suture the skin, the injured finger and neighbor are fixedby a cypsum fibrosum on extending wrist and fingers position.Dermal sutures are out about 2 weeks, pull out the Kirschner wireafter 6 weeks. Aided cypsum fibrosum or aluminous plate fixed forabout 2 weeks in night to protect the injured fingers, synchronouslystart to rehabilitated treatment.According to Patel's evaluation standard, there were 18 casesgraded as excellent, 57 cases as good, 4 cases as fair, and 1case aspoor, excellent and good rate was 93.75% by follow-up rangedfrom 1 to 11 years. The patients were satisfied with both functionand appearance.Discussion: As a result of the injury in I area of extenso-tendonequipment, the integrity of Muscle-Tendon-Bone system and thebiomechanics-balance of extensor and flexor tendon are bothdestroyed. Osseous or tendinous mallet finger deformity would bean absolute end-results.Restoring the terminal extensor apparatus is a biomechanics'sprinciple of re-establishing the integrity of Muscle-Tendon-Bonesystem. All the operations are done directly open, so goodappearances and satisfied functions would be gotten. Meanwhile theother constitutions are complete remained, these conditions areanatomical foundations to restore the functions of hands in themaximal possible. As the transplanted tendon-flap contains enoughparatenons, it can re-establish new blood circulation easily, confirmarticular capsule and keep satisfactory physiological tendinous glide,All these steps can effectually lower the cicatrical adhesive riskamong tendon, periost and articular capsule at the suture, and as faras possible avoid some complications such as recurrence, chronicache, and insufficient tendinous intension. On the other hand, mostnormal tissues are retained and the transplanted flap is not exposed,so the appearance is satisfied. Otherwise, external fixation afteroperation and intensive rehabilitation treatment are very importantto treat the chronic mallet finger deformity.Conclusion: The method is so simple and direct that almost allthe primary hospitals can carry it out. Moreover, the therapeuticeffect is certain. Indications include Type Ⅰ~Ⅲ and Type Ⅳ-B.The primary objective to design the procedure is toward thetreatment of Osseous and tendinous mallet finger deformity, but inthe clinical practice, the method also can apply the cases whichneed to be recovered the functions on the next procedure and thecases which has failed in expectant treatment. Accordingly,transplanting palmaris longus tendon-flap graft to restore terminalextensor apparatus is an available method.