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Operative Treatment of Metacarpal Shaft Frx

 



- Treatment Options:
    - percutaneous pinning w/ 1.6 mm or 2.00 m K wires in small fragments;

           
            - ref:
                   Complications of smooth pin fixation of fractures and dislocations in the hand and wrist.
                   Absorbable intramedullary implants for hand fractures. Animal experiments and clinical trial.
    - screw fixation:
            - 2.0 mm or 2.7 mm cortex screws as lag screws in spiral frx;
            - 2.0 mm screws are applied to the cortex and the 2.7 mm screws are applied to the metaphysis;
            - screws should be countersunk to remove prominent head and to improve loading characteristics;
            - generally two screws are required for metacarpal shaft fractures;
            - note: the drilling into small bones does have an effect of torsional rigidity;
                   - drilling a hole more than 30% of the shaft diameter, leads to a 90% reduction in torsional rigidity;
    - plate fixation:
            - indicated for multiple metacarpal shaft frx, or other unstable shaft fractures that cannot be help reduced w/ K wires or screws;
                   - overlying soft tissues must be intact for plate fixation;
            - in absence of comminution & intact palmar cortex, one quarter tubular plate w/ 2.7 mm screws is adequate;
                   - this will allow plate to function as a tension band plate;
            - w/ comminution, use stronger implant such as 2.7 mm DCP & consider bone grafting;
            - plates must be placed on the dorsal surface inorder to function as a tension band;
            - quater tubular plate or 2.7 mm DCP as neutralization plate, especially in lag screw fixation of second to fifth metacarpals, esp w/ spiral fractures with rotational displacement;
                   - w/ segmental defects or comminution a 2.7 mm DCP is required;
            - prebending of the plate slightly beyond the normal metacarpal bow allows restoration of the anterior cortical butress;

                   

            - references:
                   Unstable metacarpal and phalangeal fracture treatment with screws and plates.
                   Rigid internal fixation in the hand: 104 cases.
                   Rigid fixation of phalangeal and metacarpal fractures.
                   Use of a minicondylar plate for metacarpal and phalangeal periarticular injuries.
                   Complications of plate fixation in the hand skeleton.

    - surgical approach: (plate fixation)
            - see: extensor anatomy;
            - longitudinal incision made either between on the outer border of the metacarpals;
            - border metacarpals are approached thru longitudinal incisions between 2nd and thrid or fourth and fifth metacarpals;
            - juncturae tendinum interconnecting the common extensor tendons can be split to enhance exposure (tag for later repair);
            - proximally the incision may be curved to expose the CMC joints;
            - if the metacarpal head needs to be exposed the extensor mechanism may be split down the middle or may be entered thru the radial saggital band;
                    - the radial side offers better exposure to the joint than the ulnar side;
            - carefully incise thru the intrisic fascia inorder to preserve an optimal gluiding mechanism;
    - external fixation of metacarpal fractures:
            - indicated for crush, mangling, or burn injuries which occur along w/ metacarpal fractures;
            - often used in conjunction w/ soft tissue reconstructive procedures;
            - references:
                    Manipulation and external fixation of metacarpal fractures.
                    External fixation of unstable metacarpal and phalangeal fractures.
                    External fixation of metacarpal and phalangeal fractures.
                    Treatment of hand injuries by external fixation.