Development Of Squat-And-Smile Test As Proxy For Femoral Shaft Fracture-Healing In Patients In Dar Es Salaam, Tanzania

Background: There are few validated instruments that serve as a proxy for fracture-healing after lower-extremity trauma in low-resource settings. The squat-and-smile test (S&S) has been under development by SIGN (Surgical Implant Generation Network) Fracture Care International to monitor outcomes of lower-extremity long-bone fractures after intramedullary nailing in resource-limited settings. The goals of this study were to develop and identify domains of the S&S test.Methods: The S&S domains were developed through an iterative process, and consensus was achieved regarding 3: squat depth, support needed to squat, and facial expression. Adult patients with an OTA/AO type-32 femoral shaft fracture were included in this retrospective study and had the S&S administered at 6 weeks and 3, 6, and 12 months postoperatively. Two authors independently assessed photographs of the patients performing the S&S. S&S domains were correlated with the EuroQol 5-Dimensions (EQ-5D) index score, and comparisons were made between S&S domains and reoperation status. Interrater and test-retest reliability was assessed using the kappa statistic. Sensitivity and specificity analyses were performed.Results: Six hundred and nine S&S images were evaluated for 231 patients. Each domain improved over time and correlated positively with EQ-5D scores (p < 0.05). Squat depth and support needed to squat correlated with the need for a reoperation (p <= 0.01), and both had high specificity (0.95 and 0.97, respectively) for ruling out the need for a reoperation at 1 year. All 3 domains had high test-retest reliability (K = 0.95, 0.92, and 0.96). Squat depth and need for support also had strong interrater reliability (K = 0.75 and 0.78).Conclusions: The S&S is a potential tool for monitoring clinical and functional outcome of femoral shaft fractures in low resource settings. Our data support the binary assessment of squat depth and need for support, but not facial expression, as a proxy for fracture-healing. Future prospective studies in external populations are warranted to evaluate the validity, reliability, and responsiveness of the S&S.