Lesser metatarsal fractures. Incidence, management, and review

Characterizing In-Situ Metatarsal Fracture Risk During Simulated Workplace Impact Loading

Metatarsal fractures represent the most common traumatic foot injury; however, metatarsal fracture thresholds remain poorly characterized, which affects performance targets for protective footwear. This experimental study investigated impact energies, forces, and deformations to characterize metatarsal fracture risk for simulated in situ workplace impact loading. A drop tower setup conforming to ASTM specifications for testing impact resistance of metatarsal protective footwear applied a target impact load (22-55 J) to 10 cadaveric feet. Prior to impact, each foot was axially loaded through the tibia with a specimen-specific bodyweight load to replicate a natural weight-bearing stance. Successive iterations of impact tests were performed until a fracture was observed with X-ray imaging. Descriptive statistics were computed for force, deformation, and impact energy. Correlational analysis was conducted on donor age, BMI, deformation, force, and impact energy. A survival analysis was used to generate injury risk curves (IRC) using impact energy and force. All 10 specimens fractured with the second metatarsal being the most common fracture location. The mean peak energy, force, and deformation during fracture were 46.6 J, 4640 N, 28.9 mm, respectively. Survival analyses revealed a 50% fracture probability was associated with 35.8 J and 3562 N of impact. Foot deformation was not significantly correlated (p = 0.47) with impact force, thus deformation is not recommended to predict metatarsal fracture risk. The results from this study can be used to improve test standards for metatarsal protection, provide performance targets for protective footwear developers, and demonstrate a methodological framework for future metatarsal fracture research.

Classification of avulsion fractures of the fifth metatarsal base using three-dimensional CT mapping and anatomical assessment: a retrospective case series study

Background

To clarify the injury mechanism of the avulsion fracture of the fifth metatarsal combining 3-dimensional (3D) fracture mapping with anatomical measurements.

Methods

Two hundred twenty-two patients with the avulsion fractures of the fifth metatarsal base, who were admitted to our hospital from August 2015 to August 2020. The computed tomography (CT) scans were used to generate the 3-D images of all mapped fracture lines for the avulsion fractures of the fifth metatarsal base were compiled in an overall 3D image. The fifth metatarsal base of 8 unpaired lower limbs of adult Asian frozen cadaveric specimens were also dissected to observe and measure the specific locations of the attachment points of the peroneus brevis, lateral band of the plantar fascia, and peroneus tertius to the fifth metatarsal base.

Results

Based on the type of fracture line produced and the specific locations of the attachment points of the tendons or fascia, the avulsion fractures of the fifth metatarsal base can be classified into three types: type I predominantly involves the action of the lateral band of the plantar fascia; type II predominantly involves the action of the peroneus brevis; type IIIA involves the joint action of the peroneus brevis and lateral band of the plantar fascia with one fracture line, and type IIIB involves the joint action of the peroneus brevis and lateral band of the plantar fascia with two fracture lines.

Conclusion

The lateral band of the plantar fascia and peroneus brevis play a major role, either separately or together, in avulsion fractures of the fifth metatarsal base. With this knowledge, we propose a novel classification based on the injury mechanism, which can serve as a reference for clinical treatment and diagnosis.

Level of evidence

Level III, retrospective case series.

Closed Antegrade/Retrograde intramedullary fixation of central metatarsal fractures: Surgical technique and clinical outcomes

BACKGROUND

Intramedullary fixation with k-wires is a surgical option in the management of fractures of the shaft and neck of central metatarsals. The current study aimed at investigating the clinical outcomes of closed antegrade/retrograde intramedullary pinning technique.

PATIENTS AND METHODS

A total of 34 patients (26 males and eight females) with 58 metatarsal neck and shaft fractures (28 shaft and 26 neck fractures) were operated using the antegrade/retrograde intramedullary fixation technique. At the final follow-up visit, pain intensity was assessed using the visual analog scale (VAS) and foot function was evaluated by the American Orthopedic Foot and Ankle Society (AOFAS) forefoot scoring system.

RESULTS

Mean follow-up period was 18 months, ranged 12 to 34. Mean time to clinical fracture healing was 6.5 weeks, ranged 5 to 9. Bony union was occurred in all the cases. No surgical site infection was noted. Mean VAS score at the final follow-up visit was 0.28, ranged 0 to 3. At the final follow-up, the mean AOFAS score was 95.2, ranged 81 to 100.

CONCLUSION

Closed antegrade/retrograde intramedullary pinning is a minimally invasive technique to manage central metatarsal fractures. Using this technique, metatarsal alignment can be restored and good clinical outcome is achieved.

Effect of Weight-Bearing in Conservative and Operative Management of Fractures of the Base of the Fifth Metatarsal Bone

Background

There is no established principle regarding weight-bearing in conservative and operative management of fifth metatarsal base fractures.

Methods

We reviewed 86 patients with acute fifth metatarsal base fractures. Conservatively treated late or early weight-bearing patients were assigned to Group A or C, respectively. Operatively treated late or early weight-bearing patients were assigned to Group B or D, respectively. Results were evaluated by clinical union, bone resorption, and the American Orthopaedic Foot and Ankle Society (AOFAS) and Visual Analogue Scale (VAS) scores.

Results

All 4 groups had bone union at a mean of 6.9 weeks (range, 5.1–15.0). There were no differences between the groups in the AOFAS and VAS scores. In the early weight-bearing groups, there were fewer cases of bone resorption, and the bone unions periods were earlier.

Conclusions

Early weight-bearing may help this patient population. Moreover, conservative treatment could be an option in patients with underlying diseases.

Acute fractures to the proximal fifth metatarsal bone: development of classification and treatment recommendations based on the current evidence

Fractures to the proximal fifth metatarsal bone are among the most frequent injuries to the foot. Various classifications intend to distinguish different fracture entities in regard to prognosis and treatment. The most commonly used classification by Lawrence and Botte delineates three fracture zones and gives treatment recommendations based on retrospective case series. Aim of our study was to critically review the literature and reevaluate the classification and treatment recommendations based on the highest level of evidence available. We performed a systematic literature search in Medline, Embase and Cochrane library and identified six prospective trials either comparing the same treatment for different fracture entities or different treatment strategies for the same fracture entity. The studies reveal that all "tuberosity avulsion fractures" (Zone 1, according to Lawrence and Botte) heal well using functional treatment. Even multifragmentary, displaced and intraarticular fractures in Zone 1 give comparable good results. Treatment with a short leg cast leads to a significant delay in return to preinjury level when compared to functional treatment. "Jones' fractures" (Zone 2) also demonstrate good to excellent results and complete bone healing when treated functionally. In contrast, "diaphyseal stress fractures" (Zone 3) at the distal limit of the fourth-fifth intermetatarsal articulation and just distally feature a significantly higher rate of treatment failure when treated non-operatively in a non-weight bearing short leg cast. Early intramedullary screw fixation leads to a significantly shorter time to bone healing and return to sport. In conclusion, acute fractures to the proximal fifth metatarsal bone should be classified into two entities only: First, metaphyseal fractures not extending beyond the distal end of the fourth-fifth intermetatarsal articulation, as these fractures, regardless the number of fragments, displacement and intraarticular involvement, should be treated functionally. Second, meta-diaphyseal fractures located at the distal end of the fourth-fifth intermetatarsal articulation or just distally, as these fractures require early intramedullary screw fixation.

Surgical correction of metatarsal malunion

Central metatarsal malunion is sparsely described in the literature. There are differing opinions on the importance of open reduction and internal fixation for lesser metatarsal fractures and possible complications from lack of appropriate treatment for these common fractures. In general, little emphasis is placed on performing open reduction and internal fixation of displaced central metatarsal fractures. In this report, we describe 2 cases in which displaced lesser metatarsal fractures were not reduced and were treated with only immobilization. Both of the patients presented later with pain and stiffness in the area of the fractures and at the metatarsophalangeal joints. In both cases, treatment consisted of metatarsal osteotomies with realignment and fixation. In each case, this treatment provided relief of pain, increased range of motion, and return to normal activity. In cases of painful metatarsal malunion, restoration of anatomic alignment may be necessary for resolution of pain and disability.

Closed antegrade intramedullary pinning for reduction and fixation of metatarsal fractures

The purpose of this study was to present the results of the metatarsal fractures treated with a closed antegrade intramedullary pinning technique. The records of 35 consecutive patients with metatarsal fractures operated on from August 2005 to June 2010 by the authors were retrospectively reviewed. Four patients were not contactable and 1 patient refused to participate. Accordingly, the study cohort was composed of 30 patients (24 male, 6 female) with 46 metatarsal head, neck, or shaft fractures. Inclusion criteria were metatarsal head, neck, or shaft fractures with a displacement of more than 3 to 4 mm or an angulation of more than 10° in the sagittal plane. Fractures combined with Lisfranc injury or metatarsal base fractures were excluded, as were bicortical comminuted fractures or long oblique fractures. Times to bone union, limitations of motion at affected metatarsophalangeal joints, and residual pain were evaluated at 6 weeks after surgery and at final follow-up. American Orthropedic Foot and Ankle Society scale was evaluated at final follow-up. Fracture union was obtained at an average of 7.1 (range 6 to 10) weeks. Two patients had moderate limitation of metatarsophalangeal joint at 6 weeks but recovered to full range at final follow-up. Average American Orthropedic Foot and Ankle Society score at final follow-up was 96.7 (range 83 to 100) points. Closed antegrade intramedullary pinning was found to be a useful method for treating displaced metatarsal fractures and to allow immediate joint motion and partial weightbearing in a stiff-soled shoe.

Percutaneous fixation of forefoot, midfoot, hindfoot, and ankle fracture dislocations

Open reduction with rigid internal fixation is the basic principle for surgical management in foot and ankle trauma. High-risk patients present a surgical dilemma for the foot and ankle surgeon because the possible complications are magnified in this patient population. Percutaneous fixation is a unique alternative for achieving anatomic stabilization without increased physical strain to the patient. The significant advantages of percutaneous fixation include minimizing damage to the vascular supply, maintaining and preserving a stable soft tissue envelope, and decreasing the potential risk for infection. This article provides an overview of percutaneous surgical fixation methods and their role in foot and ankle trauma for the high-risk patient.

Return-to-activity levels in 96 athletes with stress fractures of the foot, ankle, and leg: a retrospective analysis

Stress fractures of the foot and ankle are common in the athletic population. Because this population is especially eager to return to activity, such fractures can be challenging to treat. If the biomechanical faults are not addressed or gradual return to activity is not monitored appropriately, fractures occasionally recur. A retrospective analysis was conducted of 96 athletes who presented to a podiatric sports medicine practice over the course of 10 years with stress fractures confirmed by radiograph or bone scan. The most common type of fracture sustained by this population was tibial stress fracture, followed by second metatarsal fracture. Marathon training was the most common pre-injury activity overall, although fitness walking was the most common activity among those with metatarsal fractures. This study relates the most common types of stress fractures of the foot, ankle, and leg to certain athletic activities and correlates duration of symptoms before presentation with return-to-activity time.

Functional treatment of acute metatarsal fractures: a prospective randomised comparison of management in a cast versus elasticated support bandage

A randomised controlled trial was performed in 50 patients with acute isolated minimally displaced lesser metatarsal fractures in order to compare plaster immobilisation with elasticated support bandage treatment. Patients treated with elasticated support bandage had significantly higher AOFAS mid-foot scores at 3-months follow-up and complained of less pain throughout the treatment period. There was no difference between the two groups in time to independent mobility, mid-foot circumference, analgesic requirements and radiological union at 3 months. As plaster casts are associated with serious complications, which were encountered in these studies, we conclude that minimally displaced metatarsal fractures are better treated without a cast.

Biomechanical study of stress in the fifth metatarsal

OBJECTIVE: The stress throughout the fifth metatarsal was determined under various loading conditions, in order to better understand the causes of fractures to this bone. DESIGN: A mathematical approach was taken, in which the stresses were analysed using the methods of beam theory. BACKGROUND: Finite element analysis has frequently been used to determine the stress in bones. Beam theory provides an easier method for determining the force and moment resultant in any cross-section. The distribution of stress throughout the cross-section can then be found by solving certain partial differential equations defined on the cross-sections. METHODS: Cross-sections of the bone were obtained by slicing a mould, into which the bone was placed, at numerous intervals along its length. Analytic expressions describing each cross-section were obtained by fitting a Fourier series to a sequence of points along the boundary. RESULTS: The maximum stress found in the fifth metatarsal resulted from an oblique load, and had a magnitude less than would occur in a subject during normal walking. CONCLUSIONS: Since the magnitude of the stress is submaximal, this study lends theoretical support to the clinical observation that the diaphyseal fracture is indeed a stress fracture. RELEVANCE: Our analysis adds a biomechanical rationale to the pathomechanics of diaphyseal stress fractures of the fifth metatarsal. It suggests that inversion during repetitive activities may predispose the foot to fractures at a predictable location.