Dynamic Imaging Evaluation in Turf Toe Injuries: A Prospective Protocol in 18 Patients

Abstract

Category Sports; Trauma Introduction/Purpose: Turf Toe remains a diagnostic challenge for the orthopedic surgeon. A high index of suspicion is needed, in addition to adequate imaging strategies to characterize the broad spectrum of injuries involving this pathology. MRI imaging provides excellent static soft-tissue details and it has become widely used to determine the anatomical structures damaged. However, defining the stability of the 1st metatarsophalangeal (MTP) plantar plate complex is difficult without proper dynamic evaluation and this is crucial to define between conservative or operative management. Since there is no current consensus regarding the optimal imaging assessment to optimize turf toe diagnosis we present the results of an imaging protocol, including dynamic fluoroscopy and ultrasound (US), to enhance the identification of unstable Turf Toe injuries. Methods: A prospective imaging protocol consisting of bilateral comparative weightbearing x-rays, US examination, and mobilization under fluoroscopy was designed. The inclusion criterion was any patient with clinical findings consistent with plantar plate injury after forced hyperextension of the hallux. All studies were informed and performed by trained musculoskeletal radiologists. Location and symmetry of the sesamoids under the metatarsal, increased distal sesamoid-to-phalanx distance and proximal migration of one or both sesamoids were suggestive findings of unstable plantar plate rupture on weightbearing x-rays. Ultrasound examination was performed to address soft tissue injuries, characterize the magnitude of the plantar plate rupture and for dynamic/comparative stability assessment. A comparative dynamic fluoroscopic evaluation was performed to evaluate the behavior of the sesamoids under maximal dorsiflexion and plantarflexion of the hallux on the lateral view. MRI was also done in all of the patients with positive findings of instability. Results: Eighteen patients (11M/7F) were evaluated under suspicion of turf toe injury from August 2016 to November 2019. The mean age was 31 years old (range:14-50). Weightbearing X-rays were positive for sesamoid complex instability in one patient. Four patients (22,2%) had positive findings for instability in fluoroscopy and US. The agreement between US and fluoroscopy was excellent (kappa coefficient 1). Assuming fluoroscopy examination as the gold standard for instability, the US was highly effective at detecting unstable injuries (Sensitivity 100%, Specificity 100%, PPV 100%, NPV 100%). Four patients positive for instability received operative treatment. Conclusion: In our series, dynamic ultrasound and fluoroscopy allowed detection of 4/18 unstable turf toe injuries compared to Weightbearing X-rays that detected only one unstable injury. US examination is highly sensitive for instability being comparable to fluoroscopic examination. Dynamic testing, with either US or fluoroscopy, in turf toe may improve the diagnosis of severe injuries, leading to higher detection of patients requiring surgical stabilization of the plantar complex.