Pain in the Post-Operative Week Predicts Pain and Hand Use Twelve Weeks after Proximal Phalangeal Fracture Fixation

Background: The purpose of this study was to determine whether baseline characteristics predict outcomes twelve weeks after open reduction and internal fixation of proximal phalangeal fracture. Methods: A cohort of patients (n = 48, mean 35 years; SD 11) commencing outpatient rehabilitation within one week of surgery were reviewed. Outcomes of interest were active PIP extension; active total range of motion; pain at rest; comprehensive pain; strength; and hand use (reported difficulty performing specific activities such as turning a door handle, as well as usual activities including housework and recreation) at twelve weeks. Possible predictors included which finger is injured, whether the fracture is intra or extra-articular, whether the dominant or non-dominant hand is injured and/or how much pain is experienced in the first post-operative week. Multiple linear regression was performed to produce a model of the prediction for each outcome of interest at Week 1 (baseline). Results: Results from multivariate linear regression analyses suggest that pain at rest at baseline was significantly predictive of pain at rest (OR = 1.25, 95% CI = 1.06-1.47),p = 0.01), comprehensive pain (OR = 3.18, 95% CI = 1.47-6.84,p = 0.01), and hand use (OR = 2.38, 95% Cl = 1.18-4.80, p = 0.02) twelve weeks after open reduction and internal fixation of proximal phalangeal fracture. The turning point on the receiver-operator characteristic curve of false versus true risk (AUC = 0.94,p = 0.04) indicated that at least a score of 4.5 on the 10 cm visual analogue scale for baseline resting pain was needed for significant likelihood of reduced hand use. Which finger was injured, location of fracture and side of injury were not predictive of any outcomes. Conclusions: Moderate to high levels of resting pain in the week following surgery for proximal phalangeal fracture is predictive of pain and hand use at twelve weeks. Moderate to high levels of resting pain should be recognised as unusual, and could be targeted in rehabilitation. Further prospective studies are needed to determine whether early identification and targeted intervention to reduce pain improves outcomes at 12 weeks.