Non-operative treatment

The current literature does not provide any randomized controlled studies (RCT) investigating non-operative versus operative treatment for Lisfranc injuries, and thus the treatment of subtle injuries (< 2 mm of displacement) is controversial (Crates et al., 2015; Faciszewski et al., 1990; Meyer et al., 1994; Nunley & Vertullo, 2002;

Shapiro et al., 1994). Even though some stable injuries might need temporary immobilization, surgery has also been recommended for even minimally displaced injuries (Myerson et al., 1986; Nunley & Vertullo, 2002). There is consensus,

however, that poor functional outcomes are associated with delayed diagnosis or the inadequate treatment of instable or displaced injuries (Stavlas et al., 2010;

Weatherford, Anderson, & Bohay, 2017). It has been argued that inadequately treated or missed non-dislocated injuries may also lead to substantial disability, deformity, and dysfunction (Curtis et al., 1993).

The current literature on non-operative treatment only includes retrospective case-series and cohort studies with relatively small patient samples (Crates et al., 2015; Curtis et al., 1993; Faciszewski et al., 1990; Myerson et al., 1986; Nunley &

Vertullo, 2002; Shapiro et al., 1994) (Table 1). For example, the study by Myerson et al. (1986) presented results after the non-operative treatment of dislocated Lisfranc injury. A total of 5 from 52 patients were treated non-operatively because they were initially missed. Four of the patients resulted in a poor result and one resulted in a fair result according to the Painful Foot Center scoring systems (Myerson et al., 1986). Nunley and Vertullo (2002) performed a study in 15 patients with subtle Lisfranc injuries, where seven patients were treated non-operatively. They suggested that only non-dislocated injuries (Stage 1) should be treated non-operatively and the injuries with displacement (Stage 2, >2 mm) between the first and second metatarsal should be treated with open or closed reduction and internal fixation (Nunley &

Vertullo, 2002). Naturally, the possibility of selection bias must be kept in mind when interpreting these results.

Curtis et al. (1993) published a study investigating the treatment of subtle Lisfranc injuries in athletes. From 19 patients, 14 stable injuries were treated non-operatively.

Patient reported outcome measures were not used in this study, and the authors classified the outcomes of treatment themselves as follows: absence of symptoms was considered as excellent, minor symptoms or signs was considered as good, residual signs of symptoms with some disability was considered as fair, and marked symptoms or signs with disability was considered as poor. The results were excellent with six patients, good with three patients, fair with four, and poor with one patient.

The non-operative protocol used was very heterogenous ranging from “none” to

“cast for ten weeks”. (Curtis et al., 1993)

Table 1.Previous studies including nonoperatively treated Lisfranc injuries. StudyPatients Intervention Primary outcomeSecondary outcomes ResultsOther Myerson et al. 19865 Lisfranc fracture dislocations based on conventional radiographs.

No treatmentFoot Function Form -Painful Foot Center (PFC) score: four had Poor result and one had Fair.

The patients had either missed diagnosis or were overlooked, and therefore did not receive any treatment Faciszewski et al. 1990 13 subtle Lisfranc injuries with diastasis (2-5 mm) between the medial cuneiform and 2nd metatarsal base in weightbearing radiographs.

Below-knee cast immobilization from 3 to 7 weeks (n=9), ORIF (n=2) or no treatment (n=4) Evaluation system by Hardcastle et al.

-Cast: 5 Good, 2 Fair, 2 Poor results. ORIF: 2 Good results. No treatment: 1 Good, 1 Fair and 2 Poor results.

Duration from injury to diagnosis was from 1 month to 1 year. Curtis et al. 199319 athletes with subtle or severe Lisfranc injury based on conventional radiography and stress fluoroscopy.

Cast immobilization from 2 to 8 weeks (n=9), crutches without cast from 2 to 4 weeks (n=2), ORIF Main and Jowett criteria

-Cast: 4 Excellent, 1 Good, 3 Fair, 1 Poor Crutches without cast: 1 Excellent, 1 Good. ORIF: 4 Excellent, 1 Good. none:1 Excellent, 1 Good, 1 Fair.

The subtle injuries were classified in 3 groups, severe injuries according to Myerson et al. Resulting in heterogenous patient sample.

(n=5) or none (n=3) Shapiro et al. 19949 elite athletes with diastasis (2-5 mm) between the 1st and 2nd TMT joints in weightbearing radiographs.

Splint for 6 weeks (n=7), ORIF (n=1) or none (n=1) Return to sports (weeks) -Cast: average 12 weeks. ORIF: 24 weeks. none: 20 weeks.

Average follow-up was 34 months. Nunley and Vertullo 2002 15 athletes: 7 with positive scintigraphy (normal weightbearing radiographs), 8 with diastasis (2-5 mm) between the medial cuneiform and 2nd metatarsal base in weightbearing radiographs

Cast for 6 weeks (n=7), early CRIF (n=6) or late ORIF (n=2) Main and Jowett criteria -Cast: 7 Excellent, early CRIF: 6 Excellent late ORIF: 1 Excellent, 1 Good

All nonoperatively treated patients were diagnosed with bone scintigraphy. Average follow-up was 27 months. Crates et al. 201536 patients with tenderness and pain in the 1st and 2nd TMT region, weightbearing radiographs findings from none to up to 2 mm of diastasis between the medial cuneiform and 2nd metatarsal base

orthosis for 6 weeks with weightbearing allowed as tolerated (n=36) Conversion to operative treatment (surgeons’ decision)

AOFAS Midfoot Scale

20/36 (56%) patients were converted to fixation with screws either mini Tight- Rope. AOFAS score, mean (range): Nonoperative 75.3 (53-100); Converted to operative treatment 92.3 (72-100).

Clinical diagnosis without findings in weightbearing radiographs. ‘Failed’ nonoperative treatment was determined by a surgeon.

Crates et al. (2015) presented a retrospective cohort study investigating the nonoperative treatment of subtle Lisfranc injuries. Altogether, 36 athletes were treated non-operatively with orthosis for six weeks, and weightbearing was allowed as tolerated. The injury diagnosis was based on clinical evaluation, i.e., if the patient had tenderness and pain in the medial TMT region combined with positive piano key test, diagnosis was confirmed without any radiological findings. Patients were then categorized into 5 groups by weightbearing radiographs. The first group comprised patients without any findings and the fifth group comprised patients with diastasis of less than 2 mm between the second metatarsal base and the medial cuneiform. The treatment was considered successful in 16 patients and the treatment failed in 20 patients, leading to conversion to operative treatment. The failure of the non-operative treatment was subjectively determined by a surgeon and the treatment was considered to have failed if the pain persisted and there were difficulties in returning to previous activities. The improvement in mean AOFAS Midfoot Score after the treatment was higher in the operatively treated patients when compared with non-operative treatment (from 64 to 92, p< 0.0001 vs. from 62 to 75, p=0.0029). They concluded that some of the patients with Nunley and Vertullo Stage 1 injuries may require surgery. The diagnosis and the definition of failed treatment were purely based on the opinion of surgeons causing a significant bias. A further limitation of this study was that they included patients with clinical symptoms without radiographic findings. Therefore, some of these patients may not have even had a Lisfranc injury. (Crates et al., 2015)

There is no consensus on the non-operative treatment protocol for non- dislocated Lisfranc injuries. Nunley and Vertullo (2002) used a protocol where stable injuries were treated non-operatively with a non-weightbearing cast for six weeks. If the patient was painless at 6 weeks, the patient could return gradually to normal activity with a orthosis during the following 4 weeks (Nunley & Vertullo, 2002). In the review by Myerson and Cerrato (2008), they suggested stable injuries should be treated with immobilization in a cast for six to eight weeks. The instability should then be assessed at two weeks with weightbearing radiographs, and if the injury remains stable, operative treatment is not needed. They suggested that weightbearing can be permitted as tolerated during the immobilization (Myerson & Cerrato, 2008).

In the presented studies, the evaluation of outcomes is conducted using non- validated foot and ankle scoring systems (Main and Jowett system, PFC score,

AOFAS Midfoot Scale), the generic health related quality of life instrument (SF-36) or the generic musculoskeletal functioning instrument (SMFA). Indeed, none of these tools have been proven to be valid or reliable in assessing outcomes after the treatment of foot and ankle injuries. Obviously, without valid PROM’s and an exact description of non-operative treatment, it is challenging to draw conclusions on the results of non-operative treatment.