First MTP joint instability - Expanding the concept of "Turf-toe" injuries

Although the classic definition of the Turf-toe injury refers to a very specific clinical and pathological picture, we think that the concept can be broadened to encompass a wide variety of traumatic lesions of the first metatarsophalangeal joint (MTP1). These are lesions typically difficult to diagnose, with a large variation of outcomes and a potential to impair patients' functional performance on a definitive and perennial basis. The objective of this study is to present the result obtained by treating 24 cases of traumatic injuries to the MTP1 joint in a midterm follow-up time.

In the period from 1999 to 2016, 24 patients were treated with MTP1 joint instability - "Expanded Turf-toe" - diagnosis. All patients were performing sports activities when they were injured: soccer (33%); martial arts (17%); running (13%); tennis (8%); olympic gymnastics (8%) and others (basketball, slalom, motorcycling, surfing, and ballet) (21%). Injuries were classified as Grade I (2 patients - 8%), Grade II (8 patients - 33%) and Grade III (14 patients - 59%) lesions. All patients with grades I and II were treated conservatively whereas those classified as grade III were treated surgically.

After an average follow-up of 4.5 years we observed an improvement in the AOFAS hallux score from 42 to 82 points after treatment (p<0.001). The most frequent cause was axial load with various direction of stress at the first MTP. The mechanism of lesion varied among extension with hallux varism (42%), pure hyperextension (25%), extension with hallux valgism (21%), pure hyperflexion (8%) and hyperflexion with hallux valgism (4%). A separate analysis of each group showed a significant improvement in AOFAS Hallux scores after treatment: 51-84 (p<0.001) and 36-81 (p<0.001) for conservative and surgical groups, respectively. Four patients with GIII injuries (29%) and two with GII injuries (20%) did not resume their previous activities. Although pre-treatment AOFAS hallux scores were significantly different between groups, post-treatment scores were similar (p=0.615).

Turf-toe is a serious injury that may prevent a high percentage of patients from resuming their previous physical activities. Mechanism of lesion might be varied generating a wide range of lesions that fit into the expanded concept of the Turf-toe injury. Both forms of treatment lead to satisfactory results if well conducted. The correct identification, classification, and grading of first metatarsophalangeal joint (MTP) instability helps in decision making and selection of the adequate treatment.

Level IV, retrospective case series.