The 71-Year-Old With a Dorsally Angulated Distal Radius and New Median Numbness
Mrs. R is a 71-year-old retired teacher who lives alone and still drives. Six hours after a fall on an icy sidewalk she presents with a distal radius fracture showing 22 degrees of dorsal tilt, 4 mm of radial shortening, a 2 mm intra-articular step-off on sagittal CT, and dorsal comminution. She reports numbness of the thumb and index finger since the fall; static two-point discrimination is 7 mm on the index pulp versus 4 mm on the uninjured side, and the median nerve is tender at the wrist. She takes apixaban for atrial fibrillation and has hypertension. Her T-score is minus 2.8. She is adamant that she will return to driving and to her bridge group within three months, and asks whether she really needs an operation.
1. Do you recommend nonoperative or operative treatment? Justify your answer with the specific radiographic parameters and patient factors, and state what you would accept as a satisfactory closed reduction if you chose that route.
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Recommendation: operative fixation. The numbers matter less than the direction in which they point:
- 22 degrees of dorsal tilt. Acceptable residual dorsal angulation after closed reduction is generally held to be within 5 to 10 degrees of neutral. At 22 degrees the radiocarpal contact shifts dorsally and terminal flexion, grip strength, and endurance all suffer.
- 4 mm of shortening. Ulnar-positive variance beyond about 2 mm correlates with distal radioulnar joint incongruity and weakness, and shortening is the deformity most likely to recur inside a cast.
- 2 mm articular step. A step of 2 mm or more in the radiocarpal joint is associated with post-traumatic arthritis.
- Dorsal comminution. This is precisely the pattern that loses position in a cast, usually within the first 10 to 14 days.
- Her goals and her bone. She lives alone, drives, and wants her hand back in three months; an osteoporotic malunion rarely delivers that.
If I did choose nonoperative care, a satisfactory closed reduction would mean dorsal tilt within 5 to 10 degrees of neutral, radial inclination of at least 15 degrees, ulnar variance within 2 mm, articular step under 2 mm, and no carpal malalignment, with radiographs repeated at 1, 2, and 3 weeks to catch collapse.
2. How do the median nerve findings change your plan and its timing? What will you do intraoperatively, and what do you tell her about prognosis?
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New numbness, provocation with wrist pressure, and two-point discrimination of 7 mm (abnormal is greater than 6 mm) after a fracture means acute carpal tunnel syndrome until proven otherwise. This converts an elective decision into an urgent one and is the most common reason a fractured wrist goes to the operating room ahead of schedule. The mechanism is usually hematoma and swelling beneath a tight transverse carpal ligament rather than laceration.
Timing: proceed with fixation within 24 to 48 hours rather than waiting for the swelling to settle. If symptoms are progressing (pain out of proportion, worsening numbness, early thenar weakness), move within hours. Coordinate apixaban reversal with anesthesia and accept a modest bleeding risk in exchange for decompression.
Intraoperatively: release the transverse carpal ligament, evacuate hematoma, and inspect the nerve for contusion or entrapment in fracture fragments. Document its appearance so that a later change has a baseline.
Counseling: most patients recover sensibility over weeks to months, but acute carpal tunnel syndrome after a fracture has a worse prognosis than the idiopathic form, and a subset of older patients are left with residual numbness. She should also be warned about disproportionate pain, swelling, and stiffness suggesting a complex regional pain syndrome, and told to report them early rather than at the three-month visit.
3. If you operate, what fixation do you choose and what are two technical pitfalls specific to her bone quality and comminution?
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A volar locking plate is reasonable even with dorsal comminution, because it functions as a fixed-angle construct that does not depend on a buttress from the dorsal cortex. Three pitfalls deserve specific attention in her:
- Dorsal screw penetration. In a fragment angulated 22 degrees dorsally, a screw measured off the volar cortex can protrude dorsally into the fourth compartment and rupture the extensor pollicis longus. Check with a true lateral and a dorsal tangential view before and after locking.
- Plate placed distal to the watershed line. In osteopenic bone there is a temptation to push the plate distally for purchase. A plate sitting on the volar rim causes flexor tendon irritation and attrition rupture, most often of the flexor pollicis longus. Aim proximal to the watershed with a rim-matched plate.
- Purchase in osteoporotic bone. Locking screws that fail to engage the far cortex, or a short plate relying on cancellous grip, will lose reduction. Use a longer plate, screws that engage the dorsal cortex, and, for severe comminution, a bridge plate or spanning external fixator rather than forcing a short plate to hold.
Finally, restore radial inclination and ulnar variance, not just volar tilt, and check the distal radioulnar joint before closing.