What is the most effective management of acute fractures of the base of the fifth metatarsal?

Journal of Family Practice, August, 2006 by Davis Vu, Todd McDiarmid

EVIDENCE-BASED ANSWER

For acute Jones' fractures in recreationally active patients, early intramedullary screw fixation results in lower failure rates and shorter times to both clinical union and return to sports than non-weightbearing short leg casting (strength of recommendation [SOR]: A, based on 2 randomized controlled trials (RCT)]. Non-weightbearing short leg casting achieves union in 56% to 100% of patients but can require prolonged casting (SOR: B, based on 2 prospective cohorts and multiple retrospective, follow-up studies). Stress fractures were not included in this review.

For avulsion fractures of the fifth metatarsal tuberosity, a soft Jones' dressing allows earlier return to pre-injury levels of activity than rigid short leg casting (SOR: B, based on a lower-quality RCT).

CLINICAL COMMENTARY

For athletes, surgical correction of all Jones-type fractures usually preferred Fifth metatarsal fractures are frequently seen in clinical practice. When faced with a fifth metatarsal fracture, determine its exact location, which influences treatment. Acute fractures to the proximal end of the bone within the cancellous bone area, if nondisplaced, do very well with closed treatment.

Fractures between the insertion of the peroneus brevis and tertius tendons, which marks a transition from mostly cancellous to relatively avascular cortical bone, can be problematic. This injury, often called a Jones fracture, needs to be identified as a chronic stress injury, which uniformly does not heal well, an acute or chronic stress injury, or a pure acute injury. For athletes, both young and old, I prefer surgical correction of all Jones-type fractures to ensure a more definitive return to athletics. For the nonathlete, I allow the patient to make an informed decision for immediate surgical correction or for an attempt at closed treatment if it is not a chronic stress failure of the bone. I find that patients who choose closed treatment and understand the possible prolonged treatment course are not upset if they need surgical treatment for nonunion and are pleased with the option and attempt of not having surgery.

Douglas F. Aukerman, MD

Family and Community Medicine, The Milton S. Hershey

Medical Center, Penn State University

* Evidence summary

Fractures within 1.5 cm of the fifth metatarsal tuberosity, without extension distal to the fourth-fifth intermetatarsal articulation, occurring with less than 2-week symptom prodrome and without a history of previous fracture, are defined as "acute Jones' fractures" (FIGURE). In a recent RCT by Mologne et al, (1) 37 active-duty military personnel with acute Jones' fractures were randomized to either 8 weeks of no weight-bearing in a short leg casting, followed by a walking cast or hard-soled shoe until clinical union; or to early outpatient intramedullary screw fixation followed by no weight-bearing for 2 weeks, then weight-bearing as tolerated in a hard-soled shoe until clinical union. Screw fixation significantly reduced both time to clinical union and time to return to sports--by nearly 50% when compared with non-weightbearing short leg casting. Furthermore, at 26 weeks the casting group saw a significant 44% failure rate compared with only 5% in the surgical group (number needed to treat [NNT]=2.6). Six patients in the surgical group had mild discomfort from the screw head, and 3 needed the screw to be removed. Generalization of the results was limited by the mostly male military population.

[FIGURE OMITTED]

The rates and times of union with short leg casting vary over a wide range in the research literature. The casting group in the RCT above had union rates of 56% and median time to union of 14.5 weeks (lower and upper quartile range, 10.5-18.5). (1) A prospective registry of 68 consecutive acute Jones' fractures in primarily young military service members showed a 72% union rate with non-weightbearing short leg casting with average time to union of 21.2 weeks. (2) A heterogeneous group of 5 retrospective follow-up studies of short leg casting reported wide ranges in union rates of 72% to 100%, and in time to healing of 7 weeks to 21 months. (3-7) These studies varied in average age, sex, and athletic ability of their samples as well as type of immobilization and weight-bearing status during treatment.

Tuberosity avulsion fractures are proximal fifth metatarsal styloid fractures resulting from a forceful pull of the lateral band of the long plantar ligament or the peroneus brevis tendon during ankle inversion. A 12-week RCT in 89 consecutive patients presenting to an emergency department with fifth metatarsal tuberosity avulsion fractures compared a nonrigid, soft Jones' dressing consisting of alternating layers of cast padding and elastic bandages with a rigid short leg casting. (8) The Jones' dressing had a significant 28% reduction in time to return to pre-injury levels of activity. Other outcomes--time in treatment modality, time to radiographic healing, and functional foot score--were not different between intervention groups. Validity was limited by the 32% lost to follow-up rate.