| Objective The ulnar nerve injury or combined with media nerve resulted inintrinsic paralysis .The deformity of claw fingers occurred with the MP jointhyperextension and IP joint flexion. Because of the sever influence on thenormal hand function, such as hand elexterity and strength, how to correct themalformation with efficiency was a great problem we had to face. The varietyof procedures available used to correct the ulnar palsy clawing of the handwhich was not attributable to the fact that none was very good but to thevariable functional deficits that appear from one patient to the next with ulnarpalsy. Now as to be agreed with by all, it was the only solution to restore thehand function by corrective intervention after nerve injure which could notrepair early or get recovered satisfactorily. Based on such a situation, wedesigned and carried out a study to biomechanically evaluate the relativeefficiency of PDF, PDF in half and palmar fascia. Then we investigated theclinical application for correction in 5 cases of claw fingers after ulnar nerveinjury between 1990 and 2005.Method and result Ten fresh symmetrical arms in adults were tested. Eachsymmetrical arm was assigned into the two groups of PDF and PDF in half.Ten palmar fascias and ten PDFs from each finger were cut down respectivelyand then 5 of the 10 PDFs were split into two tails equally. They wereconserved in the isotonic Na chloride. Testing was performed using an InstronUniversal Test Instrument (model AG-10TA; made in Japan). It would controlthe stress and strain exerted on the test sample automatically, and print out thedata of each load, elongation, stress and strain, then the curve of stresscompared with elongation. It showed that PDF and that in half could endurelarge amount of stress exerted on it with less elongation in size. The differencebetween half PDF with palmar fascia group was statistically significant(P<0.05) in maximum stress and in maximum elongation in size. Themaximum stress of half PDF was ten times larger than that of palmar fascia,while the maximum elongation in size of palmar fascia was two times biggerthan that of half PDF. In the aspect of modulus of elasticity, there was nosignificant difference between the two groups of PDF integrated and that inhalf, but it was significant weaker in half PDF than palmar fascia. Based on it,PDF in half provided us a better tendon for tenodesis than palmar fascia bybiomechanical testing, on the other hand, it avoided the disadvantage tosacrifice large amount of PDFs that would result in new disorders of hand. Inclinical application, we designed and carried out a new surgical procedure asfollows. A curved incision from the metacarpophalangeal joint crease to theposition -5cm proximal to the ligament carpi transversum exposed the tendonsheath (A1 pulley) and PDF. A further incision on PDF between A1 pulley andA2 pulley was made, then PDF was brought out and cut down proximal to thebrevi-vincula tendinum. Tension was adjusted with the MP joint in flexion of30　-40　.The proximal end of PDF was looped around the A1 pulley andsutured with itself. The distal end of PDF was sutured to its own periosteum ofeach side after the IP joint was adjusted in extension. The other incisionposition on PDF was 2cm distal to the ligament carpi transversum. Tensionwas adjusted to hold the wrist in neutral position, then looped the PDF aroundthe ligament carpi transversum and suture it with the former. The hand is heldin plaster splint and this position should be maintained for 4 weeks. Between1990 to 2005, this new surgical procedure was applied in 5 patients with clawfingers. After 4 to 11 years of follow-up visit, all the malformations werecorrected and the ability of grip was restored with no recurrence.Discussion After the ulnar nerve injury or combined with media nerve, whenintrinsic muscles to the fingers were paralyzed, they had lost the prime flexorsof the MP joints and they had also lost the ability to extend the IP joints whenthe MP joints were in hyperextension. The combination of intact long flexorsof the fingers with long extensors resulted in discoordination and a classicalclawing posture. The long extensors, attempting to extend the fingers in theabsence of balanced flexion of the MP joints, hyperextend the MP joints. In... |
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