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Treatment of Distal Radius Frx Malunion

- Discussion:
    - often patients will note pain weeks to months after the cast is removed;
    - w/ excessive dorsal tilt, will often develop a symptomatic ulnar mid-carpal instability (or carpus adaptive DISI);
            - in the report by Taleisnik and Watson (1984), the average amount of dorsal tilt which caused significant symptoms was 23 deg, however, in one case a patient had symptoms w/ 8 deg of volar tilt; 
    - Colles fracture: does the anatomical result affect the final function?
    - Midcarpal instability caused by malunited fractures of the distal radius.

- Exam:
    - w/ excessive dorsal tilt, look for:
          - symptoms may include tenderness over lunocapitate and triquetrohamate joints;
          - a painful audible snap often results from active ulnar deviation w/ forearm pronation;
          - some loss of palmar flexion is usually present;
          - grip strength is usually decreased by 50%;
    - w/ excessive radial shortening or loss of radial inclination would be more likely to affect the RU joint (limiting pronation and supination);

- Radiographs:
    - PA View
         - Radial Inclination
         - Radial Length 
    - Lateral View
         - Fat Pads (in the case of occult injury)
         - Palmar Slope 
               - look for dorsal tilt of the lunate (DISI deformity);
               - excessive dorsal tilt is associated w/ ulnar mid carpal instability (or carpus adaptive DISI);

- Opening Wedge Osteotomy:
     - preoperative consdierations:
            - this procedure is mainly indicated in young active patients;
            - ensure that the fracture is fully healed before the osteotomy is performed;
                   - if the osteotomy is performed before the frx is fully healed, the distal radius may re-fracture as the osteotomy is created;
            - radiographs of the opposite wrist should be taken inorder to help judge how much correction is necessary;
     - surgical technique:
            - dorsal approach to the distal radius;
                   - distal radius is approached between the 2nd and 4th compartments;
                   - EPL tendon is mobilized;
                   - subperiosteal dissection will maximize the amount of soft tissue between the extensor tendons and the plate;
            - in the saggital plane, a K wire is inserted perpendicular to the radial surface, at a point several cm proximal to the osteotomy site;
     - preparing for the osteotomy:
            - a second K wire is inserted just proximal to radial articular surface, at an angle subtended by it and first wire which equals amount of deformity in saggital plane;
            - finally a third K wire is inserted parallel to the joint line;
                   - this ensures that the osteotomy is parallel to the joint line;
                   - consider using flouro to confirm this, or place a wire thru the joint capsule along the articular surface of the radius;
            - Lister's tubercle is removed to produce a more flat surface for the plate;
            - osteotomy site is marked 2.5 cm proximal to the wrist joint;
            - Homan retractors are inserted to protect the volar soft tissues;
     - osteotomy:
            - osteotomy is made just proximal to the sigmoid notch;
            - in the AP plane, the osteotomy is made at right angles to the radial shaft (as opposed to making it parallel to the radial inclination);
                   - the later cut may not allow enough room for distal screw fixation;
            - in the lateral plane, the osteotomy is made parallel to the dorsal tilt;
            - osteotomy is created on dorsal and radial aspects of the distal radius, which allows lengthening and re-creation of volar tilt (against intact volar and ulnar periosteal hinge);
                   - the osteotomy is spread open w/ laminar spreaders until the K wires are parallel;
                   - on the radial side of osteotomy, the amount of opening should equal the templated radial length deficit;
                   - if present, correct any supination deformity of the distal fragment;
     - fitting the bone graft:
            - laminar spreads hold the osteotomy apart while calipers are used to measure the bony defect;
            - radiographs are taken to confirm the correction;
            - bone graft is harvested to fit the required dimensions;
            - a hall burr can be used to gently shape the bone graft;
            - typically the graft will be triangular on the lateral view, and will be trapezoidal on the AP view;
            - a plate can be used to secure the graft, but if additional fixation is needed, a lag screw can be inserted from radial styloid to the ulnar cortex of the distal radius;
     - assessment of RU joint: (see RU joint)
            - these patients will often have an ulnar impaction syndrome;
            - following opening wedge osteotomy, check passive supination and pronation;
            - w/ a significant deficit, consider Bower's arthroplasty;
            - some authors will choose a Darrach procedure





Midcarpal instability caused by malunited fractures of the distal radius.  

Correction of post-traumatic wrist deformity in adults by osteotomy, bone-grafting, and internal fixation

Opening-wedge osteotomy, bone graft, and external fixation for correction of radius malunion.

Corrective Osteotomy for Intra-Articular Malunion of the Distal Part of the Radius.