| Objective: By measuring the distal finger, we try to provide anatomical basis for treating bony mallet finger by absorbable suture tying avulsion fracture fragment, including skin incision, the entry point and angle of the needle for fixing distal interphalangeal joint, the position of the absorbable suture’s guiding hole; and we put the technique into clinical application and observe the curative effect.Methods: Randomly select 16 fresh adult upper limb specimens, including 16 thumbs, 16 index fingers, 16 middle fingers, 16 ring fingers and 16 little fingers.1. Observe the important structure of distal phalanx and design marker line: to determine the distal phalanx’s dorsal part and volar cortical border and to determine the surface projection of the distal phalanx’s middle line on the side of the finger.2. Measure the distance from the extensor terminal tendon to rear projection line of the distal finger grain(D); the distance from nail matrix proximal end to the distal tendon terminal and the width of the tendon terminal in order to design suitable length and width for skin incision.3. Determine the method and entry point and angle of Kirschner wire for fixing distal interphalangeal joint.4. Build bone mallet finger model group according to the angle between bone avulsion fracture line and the axis of the distal phalanx. Group A:15°,Group B:30°, Group C: 45°, Group D: 60°, Group E: 75°. Measure the distance between the absorbable suture entry point(O2) at bottom of distal phalanx and the distal streakline(C).5. The above data are measured with vernier caliper at an accuracy of 0.02 mm and analyzed by statistical software spss13.0, expressed by x_±s.6. Simulation experiment on fresh upper limbs of adult specimens.7. Performed the technique for the treatment of 15 bony mallet finger in 15 patients, Patient follow-up lasted 3 to 12 months. We graded the results by TAM(Total Active Movement).Results:1. At the bottom of the distal phalanx, the projection of the dorsal cortical border is at the dorsal nail fold. The projection of the volar cortical border is at the volar side of the finger’s side middle line. At the backbone of the distal phalanx, the projection of the dorsal cortical boundary and that of the volar cortical boundary is respectively at the nail fold line and the finger’s side middle line. The projection of the distal phalanx’s side middle line is at the carve line of the finger’s side middle line and nail fold line; The absorbable suture guiding hole’s best entry point is on the projection of the distal phalanx’s side middle line2. The best entry point of Kirschner wire for fixing distal interphalangeal joint is at the junction of the distal phalanx’s basilar part and the finger’s backbone. The best entry angle is 30°.3.(1) The width of the tendon terminal. Thumb:10.72±0.42 mm, Index finger: 6.14±0.33 mm, Middle finger: 6.73±0.39 mm, Ring finger:5.63±0.37 mm, Little finger:4.64±0.38 mm.(2) The distance between the tendon terminal and nail matrix proximal end. Thumb:1.53±0.12 mm, Index finger: 1.46±0.08 mm, Middle finger: 1.48±0.07 mm, Ring finger:1.42±0.07 mm, Little finger:1.42±0.08 mm.(3) The distance between tendon terminal and the rear projection line of the distal streakline. Thumb:6.12±0.55 mm, Index finger: 5.03±0.36 mm, Middle finger: 5.15±0.32 mm, Ring finger:4.89±0.36 mm, Little finger:4.02±0.24 mm.(4) The distance between Kirschner wire for fixing distal interphalangeal joint and the distal streakline. Thumb:8.86±0.44 mm, Index finger: 8.05±0.44 mm, Middle finger:8.60±0.40 mm, Ring finger:8.27±0.39 mm, Little finger:7.78±0.41 mm.(5) The distance between the absorbable suture entry point at bottom of distal phalanx and the distal streakline.Group A 15°: Thumb 7.22±0.42 mm, Index finger 7.00±0.40 mm, Middle finger 7.02±0.41 mm, Ring finger:6.26±0.44 mm, Little finger 5.54±0.43 mm.Group B 30°: Thumb 9.11±0.36 mm, Index finger 8.79±0.40 mm, Middle finger 8.91±0.39 mm, Ring finger 8.05±0.55 mm, Little finger 7.33±0.50 mm.Group C 45°: Thumb 10.28±0.30 mm, Index finger 9.84±0.30 mm, Middle finger 9.92±0.32 mm, Ring finger 9.01±0.51 mm, Little finger 8.19±0.52 mm.Group D 60°: Thumb 11.52±0.29 mm, Index finger10.91±0.36 mm, Middle finger10.93±0.42 mm, Ring finger 9.95±0.48 mm, Little finger 9.14±0.56 mm.Group E 75°: Thumb 13.73±0.34 mm, Index finger 12.99±0.38 mm, Middle finger 12.96±0.43 mm, Ring finger 12.08±0.46 mm, Little finger 11.33±0.57 mm.4. Simulation experiment has validated that the measured data can be used as a reference in surgery.5. All fractures united in all 15 patients. The evaluation results based on TAM: excellent in 6 cases, good in 7 cases, fair in 2 cases, no poor cases, good rate was 86.7%.Conclusions:Design U-shape incision at the distal interphalangeal joint, starting from the streakline on the palm side and no farther than the proximal nail matrix., forming a tongue-shaped flap. The width of the incision is 4-5mm than that of the terminal tendon.Distal interphalangeal joint tendon fixes at 0 ° position. Insert Kirschner wire at 0.5 ~ 1.0 mm at the palmar side of the surface projection line. The best entry point is at the junction of the distal phalanx’s basilar part and the finger’s backbone. The best entry angle is 30°. The distance between the entry point and the distal streakline: Thumb13 mm, index finger 12 mm, middle finger 13 mm, ring finger 12 mm, little finger 11 mm.The best entry point of absorbable suture guiding hole is on the side middle line of the distal phalanx.This method is simple and easy to master, with strong fixation and small economic burden and trauma, and also no foreign substance left. |
PDF Full Text Request