Deterioration of initially accepted radiological alignment of conservatively treated AO type-C distal radius fractures: mid-term outcome.

BACKGROUND AND AIMS: It still remains controversial how often the once-accepted radiological alignment of an AO type-C distal radius fracture deteriorates after conservative treatment, and to what extent this deterioration is perhaps associated with patient-rated outcome measures (PROms). Thus, we aimed to evaluate this radiological deterioration and its association with mid-term functional follow-up.

PATIENTS AND METHODS: We retrospectively reviewed 66 patients (mean age at fracture 53 years, SD 14.1, range 18-73, female 65%) with 68 C-type distal radius fractures at a mean of 6.7 years (SD 0.5 years, range 5.8-7.7 years) after primary closed reduction and cast immobilization. Radiographs of the wrists were taken and analysed for any radial shortening, dorsal tilt or step-off at the joint surface. Range of motion and grip strength were measured. In addition to the radiological result, primary outcome measures included Quick Disabilities of the Arm, Shoulder and Hand (QDash) and Patient-Rated Wrist Evaluation (PRWE).

RESULTS: At mid-term follow-up, an acceptable anatomical radiological result was seen in only 22 wrists (32%). Deterioration of the once-achieved and accepted primary alignment was seen in a majority of cases (68%). Radial shortening of ≥ 2 mm was found in 34 wrists (51%, mean 4 mm, range 2-8 mm), with no association with QDash (12.8 vs. 5.5, p = 0.22) or PRWE (9.1 vs. 5.7, p = 0.40). Only four patients (6%) showed step-off at the joint surface (mean 1.1 mm, range 0.5-2 mm). Twenty-two wrists (32%) showed dorsal tilt of ≥ 10° (five with volar tilt of 15°-25°), with no effect on QDash or PRWE (14.7 vs. 6.5, p = 0.241 and 10.1 vs. 5.8, p = 0.226). Altogether, patients with dorsal tilt, step-off or shortening did not show significantly worse QDash (10.3 vs. 5.7, p = 0.213) or PRWE (8.1 vs. 5.1, p = 0.126) versus those with none. Twenty-nine (43%) of the patients had deficits in range of motion (ROM), either in extension (39%), flexion (43%), supination (16%) or pronation (4%), or combinations of these. Worse extension was associated with worse QDash (15.9 vs. 5.0, p = 0.037), flexion deficit with worse PRWE (11.5 vs. 4.4, p = 0.005) and supination deficit with both QDash (21.7 vs. 6.8, p = 0.025) and PRWE (18.9 vs. 5.2, p = 0.007).

CONCLUSIONS: The initially accepted radiological alignment of AO type-C radius fractures deteriorated in a majority of cases during conservative treatment. However, this deterioration was fairly mild and showed no significant association with functional outcome. Restricted ROM showed some association with PROms.

LEVEL OF EVIDENCE: IV.