Fifth metatarsal fractures in skeletally immature patients do not need routine orthopedic surgeon assessment and follow-up

Abstract

Objectives

The aim of this study was to determine the rate of delayed or nonunion of fifth metatarsal fractures in skeletally immature patients. Using this information, we sought to develop an evidence-based clinical care pathway in order to mitigate unnecessary patient radiation exposure, costs to families, and costs to the health system.

Methods

We retrospectively reviewed the charts and radiographs of patients who presented to an academic tertiary-care paediatric hospital between 2009 and 2014 with isolated fifth metatarsal fractures.

Results

A total of 114 patients (61 males and 53 females) with mean age of 11.2 (SD 3.0) years old were included in the study. No patients required operative management. There was one case of delayed union and no cases of nonunion. There was no association of these complications with fracture type, location, or mechanism of injury. There was no association of complications with immobilization type or immobilization period. Despite the low complication rate and need for surgery, fracture clinic resource utilization was significant. Fractures were managed with a mean number of 3.1 (SD 0.89) clinic visits and a mean number of 2.7 (SD1.0) radiology department visits where a mean total of 7.9 (SD 3.4) x-rays were performed.

Conclusions

Based on our retrospective review, skeletally immature patients presenting with isolated fifth metatarsal fractures have a very low rate of delayed or nonunion. A selective follow-up strategy will decrease radiation exposure, reduce costs to families and the healthcare system, without compromising clinical outcomes.

Fifth metatarsal fractures are the most common metatarsal fracture in children and account for 6% of paediatric fractures (1,2). Due to little mention in the paediatric literature, clinicians managing paediatric fifth metatarsal fractures, often rely on the adult literature to guide management. This leads to frequent and lengthy follow-up because of the high rate of nonunion seen in adults (i.e., the Jones Fracture) (3). This incurs direct costs to the health care system, as well as indirect costs to parents, who must miss work on account of their child’s appointments (4,5). There is also the potential harm of exposing children to unnecessary ionizing radiation from unnecessary serial radiographs.

Management recommendations for adult fifth metatarsal fractures are typically based on the anatomical classification of the fracture location, due to varying clinical outcomes in each location (6–9). In particular, the Jones fracture, defined as a fracture at the proximal metaphyseal-diaphyseal junction or proximal diaphysis of the fifth metatarsal, is known to have prolonged healing time due to the watershed pattern of bone perfusion in this region, that may result in symptomatic delayed or nonunion (3,6,9). Regardless, the majority of fifth metatarsal fractures in adults are treated nonsurgically with immobilization, and achieve clinical union in approximately 6 weeks (8,10). In adults, Nagar et al. recommended an initial x-ray to diagnose, classify, and plan treatment of the fracture, with subsequent radiographs only indicated in patients with a Jones fracture or who are still symptomatic at 8 weeks and may benefit from surgical intervention. Otherwise, asymptomatic patients are discharged on clinical grounds as soon as possible, with no further radiographic confirmation or follow-up indicated (11).

In paediatric patients, there remains controversy over which fifth metatarsal fractures require prolonged immobilization and follow-up due to greater healing and remodeling potential of skeletally immature patients (6,12). Two recent articles recommend using anatomical location of the fracture as a guide for treatment (6,12). However, both of these studies defined children based on age (<18 years old) rather than skeletal maturity and therefore included patients with fused physes. Furthermore, neither article included any recommendations for clinical and radiographic follow-up.

The objective of this study was therefore to determine the rate of symptomatic delayed union and nonunion in skeletally immature patients with fifth metatarsal fracture and the rate of surgical intervention required in this population.

METHODS

Following Research Ethics Board approval, we retrospectively reviewed all patients with fifth metatarsal fractures who presented at The Hospital for Sick Children, Toronto, Ontario, from January 2009 through December 2014. The patients were identified via a radiology department search conducted on the hospital’s ISYS radiology database (ISYS, Odyssey Development, Inc.) using the key words ‘(metatarsal* OR Jones) AND fracture*’. Inclusion criteria comprised patients up to 18 years of age who were skeletally immature (defined as open physes on injury radiographs) with an isolated fifth metatarsal fracture confirmed by a paediatric radiologist on initial injury radiographs. Patients with multiple fractures, polytrauma, nonaccidental injury, underlying bone disease, pathologic fractures, stress fractures, closed physes, and patients referred to our fracture clinic after being treated at another institution were excluded.

The patients typically presented to the emergency department of our institution. They were initially immobilized and referred by the emergency department physician to our orthopedic fracture clinic.

Inpatient and outpatient charts were reviewed using the Electronic Patient Chart system, while radiographs were reviewed using the Picture Archiving and Communication System.

Basic demographic variables were collected, including age, sex, previous injury to the same foot, mechanism of injury, other associated injuries, surgical intervention, and complications. Characteristics of the fracture were obtained from the radiographs and radiologist reports, including fracture side (left, right, and both), type (simple and comminuted), anatomical location (zone, length in mm), physeal involvement, and displacement (6,8,12). Temporal variables such as return to sport, time to resolution of pain on palpation at fracture site, and radiographic union were also recorded when available. Symptomatic nonunion was defined as failure to show radiographic progression for 3 months or to unite by 9 months and persistent symptoms such as pain associated with these radiographic findings (13). All continuous variables are presented as a mean, while categorical variables are presented as a percentage.

Symptomatic nonunion was the primary outcome. Surgical treatment rate was the secondary outcome.

Descriptive statistics were used to describe the patients’ demographics and the proportion of patients requiring surgical intervention.

RESULTS

A total of 114 patients (61 males and 53 females) with a mean age of 11.2 (range 2.5 to 17.1) were included in the study. All patients were treated nonsurgically. Supplementary Appendix 1 outlines the process of inclusion and exclusion throughout the ISYS and full-chart review on Electronic Patient Chart.

The most common mechanism of injury was inversion injury (74.6%) (Table 1). The majority of fractures were in the transverse orientation (60.5%), with avulsion (14.0%), oblique (14.0%), and other types of fractures being less common. With respect to fracture location, 50.9% of fractures were apophyseal, 24.6% were at the neck/shaft, 18.4% were intra-articular, and 6.1% were at the metaphyseal-diaphyseal junction (i.e., Jones fracture) (Table 2).

Table 1.

Fracture characteristics

	Total (N=114)
Fracture side
Left	63 (55.3%)
Right	51 (44.7%)
Fracture type
Transverse	69 (60.5%)
Avulsion	16 (14.0%)
Oblique	16 (14.0%)
Buckle	5 (4.4%)
Spiral	2 (1.8%)
Comminuted	1 (0.9%)
Missing	5 (4.4%)
Fracture location
Apophyseal	58 (50.9%)
Neck/Shaft	28 (24.6%)
Intra-articular	21 (18.4%)
Jones*	7 (6.1%)
Mechanism of injury
Inversion Injury	85 (74.6%)
Fall	18 (15.8%)
Contact	5 (4.4%)
Missing	6 (5.3%)

*Jones fracture = fracture of fifth metatarsal through the metaphyseal-diaphyseal junction.

Table 2.

Management and outcome information

	Total (N=114)
Number of clinic visits	3.1 (SD = 0.89)
Number of radiology visits	2.7 (SD = 1.0)
Number of x-rays	7.9 (SD = 3.4)
Days from injury to x-ray	1.8 (SD = 4.0)
Initial immobilization type
Back-slab	71 (62.3%)
Walking boot	28 (24.6%)
Short-leg cast	4 (3.5%)
Crutches only	4 (3.5%)
Stiff-soled shoe	3 (2.6%)
Tensor	1 (0.9%)
No immobilization	2 (1.8%)
Missing	1 (0.9%)
Final immobilization type
Walking boot	61 (53.5%)
Stiff-soled shoe	25 (21.9%)
Short-leg cast	14 (12.3%)
Back-slab	10 (8.8%)
Crutches only	1 (0.9%)
No immobilization	2 (1.8%)
Missing	1 (0.9%)
Radiographic union
Confirmed	19 (16.7%)
Discharged from clinic before confirmation	95 (83.3%)
No	0 (0%)
Resolution of pain to palpation
Confirmed	78 (68.4%)
Discharged from clinic before confirmation	36 (31.6%)
No	0 (0%)
Mean time from injury to resolution of pain to palpation (days) (min-max)	32 (6–61)
Mean time from injury to radiographic union (days) (min-max)	60 (27–200)
Complications
Nonunion	0 (0%)

The mean number of clinic visits, including initial consultation in the emergency department was 3.1 (±0.89) (Table 2). The mean number of radiology department visits was 2.7 (±1.0), where patients received an average of 7.9 (±3.4) total radiographs. The initial radiograph occurred 1.8 (±4.0) days after injury (Table 2).

All of the fractures were managed nonoperatively. Initial immobilization was achieved through a back-slab in 62.3% of patients; however, 53.5% of patients were eventually transitioned to a prefabricated walking boot.

68.4% of patients were followed until pain free on palpation of the fracture site. Pain resolution took an average of 32 days (ranging from 6 to 61 days). 16.7% of patients were followed until radiographic union which occurred on average 60 days after injury.

No complications were documented. No patient had a documented symptomatic nonunion necessitating surgical management (Table 2).

DISCUSSION

We reviewed skeletally immature patients with fifth metatarsal fractures treated at our institution. Despite the short follow-up period, no patient had documented symptomatic nonunion and no patient required surgical treatment of their fifth metatarsal fracture.

Existing literature for both paediatric and adult fifth metatarsal fracture management has focused on the anatomical location of the fracture as the main prognostic indicator regarding healing. There are only two existing published studies that suggest a treatment approach for paediatric patients presenting with isolated fifth metatarsal fracture, both of which suggest using fracture location in the Jones region to recognize children who may require surgery (6,12).

In 2007, Herrera-Soto et al. retrospectively reviewed 103 patients with fifth metatarsal fractures. They classified the fractures into three types (fleck fracture, intra-articular fracture, and Jones fractures). The average time to healing ranged from 4 to 12 weeks depending on fracture type, Jones taking the longest time. Two of 15 patients in the Jones group underwent primary surgical treatment and 3 underwent surgical treatment for refractures. They noted that delayed healing or refracture in Jones type fracture where almost exclusively seen in patients older than 13 years old (6).

More recently, a retrospective series of 238 paediatric metatarsal fractures from a single institution by Mahan et al. suggested a simple ruler measurement from the proximal tip of the fifth metatarsal as a way to identify paediatric patients who are most likely to need surgical intervention (12). This study suggested that the 20–40 mm region, which is the approximate zone of the Jones fracture, to be most at risk of delayed or nonunion. In their cohort, 6 of the 43 patients who were identified with fractures in this region were managed with surgical intervention. Nine of the 15 patients who received surgery were over 13 years old and 6 were over 16 years old. Additionally, in 5 of the 15 surgically managed fractures, surgery was performed within 5 weeks of injury, presumably not for nonunion. In one case, a surgical approach was pursued in order to facilitate early return to sport (12).

The previously mentioned studies suggest that Jones type fractures (proximal metaphyseal-diaphyseal junction) have a higher rate of delayed union, nonunion, and refracture. However, most of these complications were observed in older children. These two cohorts also included skeletally mature patients. In the Mahan et al. (12) series, no patient under the age of 11 years old required surgery and only 2 patients under the age of 13 years old required surgery for nonunion. Similarly, in the Herrera-Soto et al. group (6), three patients underwent surgical fixation for refracture of Jones type fractures; they were all over 13 years old. Only two patients underwent initial fixation. The average age of the surgical patients was 15.5 years old.

Our study only looked at skeletally immature patients and did not find any documented symptomatic delayed union or nonunion. The different age range and maturity between previously published work and this current cohort may explain the lowest rate of complication and surgical treatment. However, a study presented at the 2020 Pediatric Orthopaedic Society of North America Annual Meeting by Davidson and al found similar outcomes. The authors retrospectively reviewed 305 patients with proximal fifth metatarsal fractures but did not specify the age. Five patients were treated surgically. Of these, faster return to sport was mentioned as the indication in four patients. All fractures treated nonsurgically healed. Mean time to healing varied according to location and varied between 5.5 and 8.3 weeks (14).

Our primary limitation is the retrospective nature of our review, leading to selection and information biases and limited follow-up data. This being said, our institution is the only tertiary care paediatric hospital in a region of 6 million people, so it seems likely that children with complications would have been included in this cohort. Another limitation is the relatively small numbers in our cohort.

In conclusion, the results from our series and review of the literature suggest that skeletally immature patients presenting with an isolated fifth metatarsal fracture can be managed conservatively with immobilization-type chosen based on initial symptoms, physical examination, and patient or provider preference. Given the low rate of symptomatic nonunion, skeletally immature patients with isolated fifth metatarsal do not require routine clinical or radiographic follow-up.

SUPPLEMENTARY DATA

Supplementary data are available at Paediatrics & Child Health Online: Supplementary Appendix 1. Patient flow diagram.

Funding: The Hospital for Sick Children Perioperative Services Summer Studentship.

Potential Conflicts of Interest: All authors: No reported conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.