Site-specific loading at the fifth metatarsal base in rehabilitative devices: implications for Jones fracture treatment

Biomechanical effectiveness of controlled ankle motion boots: A systematic review and narrative synthesis

INTRODUCTION

Controlled ankle motion (CAM) boots are a below-knee orthotic device prescribed for the management of foot and ankle injuries to reduce ankle range of motion (RoM) and offload the foot and ankle whilst allowing continued ambulation during recovery. There is a lack of clarity within the current literature surrounding the biomechanical understanding and effectiveness of CAM boots.

AIMS

To summarise the biomechanical effects of CAM boot wear as an orthotic for restricting ankle RoM and offloading the foot.

METHODS

A systematic literature review was conducted in accordance with the PRISMA 2020 guidelines. All papers were independently screened by two authors for inclusion. Methodological quality was appraised using Joanna Briggs Critical Appraisal checklists. A narrative synthesis of all eligible papers was produced.

RESULTS

Thirteen studies involving 197 participants (113 male and 84 female) were included. All studies were quasi-randomised and employed a within-study design, of which 12 studies included a control group and a range of CAM boots were investigated. CAM boots can be seen to restrict ankle RoM, however, neighboring joints such as the knee and hip do have kinetic and kinematic compensatory alterations. Plantar pressure of the forefoot is effectively redistributed to the hindfoot by CAM boots.

CONCLUSION

The compensatory mechanisms at the hip and knee joint during CAM boot wear could explain the secondary site pain often reported in patients, specifically at the ipsilateral knee and contralateral hip. Although CAM boots can be used to restrict ankle motion, this review has highlighted a lack of in-boot kinematic analyses during CAM boot use, where tracking markers are placed on the anatomical structure rather than on the boot, or through video fluoroscopy, urging the need for a more robust methodological approach to achieve this. There is a need for studies to assess the biomechanical alterations caused by CAM boots in populations living with foot and ankle pathologies. Future research, adopting a longitudinal study design, is required to fully understand the effectiveness of CAM boots for rehabilitation.

Short-Term Outcomes of Jones-Specific Implant Versus Intramedullary Screw and Plate Fixation for Proximal Fifth Metatarsal Fractures

Although intramedullary screw fixation is commonly performed for proximal fifth metatarsal fractures, high rates of nonunion, refracture, and hardware prominence have been reported. The Jones Specific Implant (JSI) is a novel surgical implant which contours to the native curvature of the fifth metatarsal allowing for a more anatomic fixation. The purpose of this study was to compare short-term complication rates and outcomes of patients treated with the JSI to other fixation types such as plates and intramedullary screws. Electronic records were queried for adult patients with proximal fifth metatarsal fractures who underwent primary fixation from 2010 to 2021. All patients were treated by a foot and ankle fellowship-trained surgeon with intramedullary screws, plates, or JSI (Arthrex Inc., Naples, FL). Visual analog scale (VAS) and the American Orthopedic Foot and Ankle Score (AOFAS) were recorded and compared using univariate statistics. Eighty-five patients underwent fixation using intramedullary screw (n = 51, 60%), plate (n = 22, 25.9%), or JSI (n = 12, 14.1%) with a mean follow-up of 11.1 ± 14.6 months. The total cohort demonstrated a significant improvement in VAS pain (p < .0001) as well as AOFAS (p < .0001) scores. When comparing the cohort treated with JSI and the cohort treated with all other types of fixation, there were no significant differences in postoperative VAS or AOFAS scores. Only 3 complications, one with JSI (3.5%) required removal of the symptomatic hardware. The JSI is a novel treatment for proximal fifth metatarsal fractures, with similar early outcomes and complication rates when compared with intramedullary screw and plate fixation.

Medical and Biomechanical Risk Factors for Incident Bone Stress Injury in Collegiate Runners: Can Plantar Pressure Predict Injury?

Background:

Bone stress injury (BSI) is a common reason for missed practices and competitions in elite track and field runners.

Hypothesis:

It was hypothesized that, after accounting for medical risk factors, higher plantar loading during running, walking, and athletic movements would predict the risk of future BSI in elite collegiate runners.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

A total of 39 elite collegiate runners (24 male, 15 female) were evaluated during the 2014-2015 academic year to determine the degree to which plantar pressure data and medical history (including Female and Male Athlete Triad risk factors) could predict subsequent BSI. Runners completed athletic movements while plantar pressures and contact areas in 7 key areas of the foot were recorded, and the measurements were reported overall and by specific foot area. Regression models were constructed to determine factors related to incident BSI.

Results:

Twenty-one runners (12 male, 9 female) sustained ≥1 incident BSI during the study period. Four regression models incorporating both plantar pressure measurements and medical risk factors were able to predict the subsequent occurrence of (A) BSIs in female runners, (B) BSIs in male runners, (C) multiple BSIs in either male or female runners, and (D) foot BSIs in female runners. Model A used maximum mean pressure (MMP) under the first metatarsal during a jump takeoff and only misclassified 1 female with no BSI. Model B used increased impulses under the hindfoot and second through fifth distal metatarsals while walking, and under the lesser toes during a cutting task, correctly categorizing 83.3% of male runners. Model C used higher medial midfoot peak pressure during a shuttle run and triad cumulative risk scores and correctly categorized 93.3% of runners who did not incur multiple BSIs and 66.7% of those who did. Model D included lower hindfoot impulses in the shuttle run and higher first metatarsal MMP during treadmill walking to correctly predict the subsequent occurrence of a foot BSI for 75% of women and 100% without.

Conclusion:

The models collectively suggested that higher plantar pressure may contribute to risk for BSI.

Dynamic Loading Assessment at the Fifth Metatarsal in Elite Athletes With a History of Jones Fracture

OBJECTIVE

We hypothesize that athletes who have suffered Jones fractures will apply significantly higher loads at the fifth metatarsal base during athletic activities compared with matched uninjured athletes.

DESIGN

Sixteen athletes were recruited to participate. Eight athletes had a history of Jones fracture, and 8 age, gender, and position-matched athletes without a history of foot injury were recruited as controls.

SETTING

Institutional study at Stanford University.

PARTICIPANTS

Sixteen athletes with/without a history of foot injury from Stanford University.

INTERVENTIONS

Athletes performed a standardized series of movements while wearing calibrated, wireless pressure mapping insoles, and then again with their custom corrective insoles.

MAIN OUTCOME MEASURES

Peak pressure, mean pressure, maximum force, and force-time integral (ie, impulse) were recorded for each activity.

RESULTS

Athletes with a history of Jones fracture showed a significantly increased peak pressure (183 ± 23 vs 138 ± 7 kPA), mean pressure (124 ± 14 vs 95 ± 4 kPA), and maximum force (15 ± 1.2 vs 12 ± 1.2%BW) at the fifth metatarsal base during walking and running compared with uninjured matched controls (all P < 0.05).

CONCLUSIONS

Athletes with a history of Jones fracture exert significantly increased peak and mean forces at the base of the fifth metatarsal during common athletic activities. Custom orthoses do not seem to offload this region in all cases. Increased loads may contribute to the development of stress injury to the fifth metatarsal during repetitive loading, and ultimately fracture of the bone.

Surgical Management of Proximal Fifth Metatarsal Fractures in Elite Athletes: A Systematic Review

Background

As a result of the high physical demand in sport, elite athletes are particularly prone to fifth metatarsal fractures. These injuries are typically managed surgically to avoid high rates of delayed union and allow for quicker return to play (RTP).

Purpose

To review studies showing clinical and radiographic outcomes, RTP rates, and complication rates after different surgical treatment modalities for fifth metatarsal fractures exclusively in elite-level athletes.

Study Design

Systematic review; Level of evidence, 4.

Methods

A systematic search was conducted within the PubMed, Scopus, and Cochrane databases from January 2000 to January 2020. Inclusion criteria consisted of clinical outcome studies after operative management of fifth metatarsal fractures in elite athletes. Exclusion criteria consisted of nonoperative management, high school or recreational-level athletic participation, nonclinical studies, expert opinions, and case series with <5 patients.

Results

A total of 12 studies met inclusion and exclusion criteria, comprising 280 fifth metatarsal fractures treated surgically. Intramedullary screw fixation was the most common fixation construct (47.9%), and some form of intraoperative adjunctive treatment (calcaneal autograft, iliac crest bone graft, bone marrow aspirate concentrate, demineralized bone matrix) was used in 67% of cases. Radiographic union was achieved in 96.7% of fractures regardless of surgical construct used. The overall mean time to union was 9.19 weeks, with RTP at a mean of 11.15 weeks. The overall reported complication rate was 22.5%, with varying severity of complications. Refracture rates were comparable between the different surgical constructs used, and the overall refracture rate was 8.6%.

Conclusion

Elite athletes appeared to have a high rate of union and reliably returned to the same level of competition after surgical management of fifth metatarsal fractures, irrespective of surgical construct used. Despite this, the overall complication rate was >20%. Specific recommendations for optimal surgical management could not be made based on the heterogeneity of the included studies.

Treatment of Zone 1 Fractures of the Proximal Fifth Metatarsal With CAM-Walker Boot vs Hard-Soled Shoes

BACKGROUND

Zone 1 fractures of the proximal fifth metatarsal are usually treated nonsurgically using some type of immobilization. The aim of this study was to compare clinical and functional outcomes, time to return to prior activity levels, and rate of bone healing when using a hard-soled shoe (HSS) vs a controlled ankle motion (CAM)-walker boot (CWB).

METHODS

Seventy-two consecutive patients with zone 1 fractures of the fifth metatarsal base were treated conservatively with either an HSS or CWB by 2 different providers. We included 57 women and 15 men, average age of 41.3 (range, 16-88) years. Radiographic findings, visual analog scale (VAS) for pain, and American Orthopaedic Ankle & Foot Society (AOFAS) midfoot score were assessed. Patients were followed at 4, 8, 10, 12, and 24 weeks or until asymptomatic and able to return to prior level of activities. Statistical analysis was performed using Mann-Whitney U, Fisher exact, and chi-square tests. P values <.05 were considered significant.

RESULTS

Age and gender distributions were similar in both groups (P = .23 and P = .57). Patients had similar VAS and AOFAS scores after 8 (P = .34 and P = .83) and 12 (P = .87 and P = .79) weeks. Average time for bone healing was significantly faster using the CWB (7.2 weeks) when compared to the HSS (8.6 weeks) (P < .001). The average time to return to prior level of activities was similar in both groups (8.3 weeks for CWB and 9.7 weeks for HSS) (P = .11). Fracture displacement was equal in both groups, with a mean of 1.9 mm of displacement in patients using the HSS, and a mean of 1.6 mm in those using the CWB (P = .26).

CONCLUSION

Zone 1 fractures of the proximal fifth metatarsal can be treated conservatively with either a hard-soled shoe or a CAM-walker boot. Even though patients treated in the CAM-walker boot demonstrated earlier signs of complete healing, similar clinical and functional results were achieved with both treatments.

LEVEL OF EVIDENCE

Level III, retrospective comparative series.

MODIFYING MIDSOLE STIFFNESS of BASKETBALL FOOTWEAR AFFECTS FOOT and ANKLE BIOMECHANICS

Background

There is a growing incidence of foot injuries in basketball, which may be from the sport's repetitive, forceful multi-directional demands. Modifying midsole stiffness of the basketball shoe has been reported to alter ankle motion and plantar forces to reduce the risk of injury; however, the effects on anatomical, in-shoe foot (metatarsal), motion is not well understood.

Purpose

The purpose of this study was to identify differences in foot and ankle biomechanics between basketball shoes with differing midsole stiffness values during single-leg jump landings. It was hypothesized that a stiffer midsole would elicit lower 1^st metatarsophalangeal joint (MTPJ) dorsiflexion angles, higher ankle dorsiflexion angles, and higher plantar forces and relative loading in the distal foot.

Study Design

Experimental cross-sectional study.

Methods

Twenty high school and collegiate-aged basketball players performed a single-leg side drop jump and a single-leg cross drop jump in a pair of standard basketball shoes and a pair of shoes modified with a fiberglass plate to increase midsole stiffness. Three-dimensional motion analysis and flexible insoles quantified foot and ankle kinematics and plantar force distribution, respectively. Separate 2 (footwear) × 2 (task) repeated measures ANOVA models were used to analyze differences in 1) ankle kinematics, 2) 1^st metatarsophalangeal kinematics, 3) maximal regional plantar forces, and 4) relative load.

Results

The stiffer shoe elicited decreased peak ankle plantarflexion (mean difference = 5.8 °, p = 0.01) and eversion (mean difference = 6.6 °, p = 0.03) and increased peak ankle dorsiflexion angles (mean difference = 5.0 °, p = 0.008) but no differences were observed in 1^st MTPJ motion (p > 0.05). The stiffer shoe also resulted in lower peak plantar forces (mean difference = 24.2N, p = 0.004) and relative load (mean difference = 1.9%, p = 0.001) under the lesser toes.

Conclusions

Altering the midsole stiffness in basketball shoes did not reduce motion at the MTPJ, indicating that added stiffness may reduce shoe motion, but does not reduce in-shoe anatomical motion. Instead, a stiffer midsole elicits other changes, including additional ankle joint motion and a reduction in plantar forces under the lesser toes. Collectively, this indicates that clinicians need to account for unintended compensations that can occur throughout the kinetic chain when altering a shoe property to alleviate a musculoskeletal injury.

Level of Evidence

2b.

Associated Joint Pain With Controlled Ankle Movement Walker Boot Wear

Background:

Controlled ankle movement (CAM) walker boots may cause gait alterations and leg-length discrepancy. This study evaluates secondary site pain relating to immobilization in a CAM walker boot.

Methods:

Patients wearing a CAM walker boot were prospectively enrolled and evaluated for new or worsened secondary site pain. Surveys at four time points were completed to evaluate secondary site pain severity and its effect on function.

Results:

The study included 46 patients (mean age, 49 years). At transition out of the boot (mean, 4.2 weeks), 31 patients (67%) reported pain which was new or worse than at baseline. The sites most susceptible to pain were lower back, contralateral hip, and ipsilateral knee. Most pains (84%) began within the first 2 weeks of boot wear. Secondary site pain was less common after transition out of the boot: 18 patients (39%) at 1 month and 15 patients (33%) at 3 months.

Conclusion:

Secondary site pain after CAM walker boot wear is common. The frequency and severity of pain lessened after transition out of the boot. Yet, one-third of patients still had new or worsened secondary site pain 3 months after cessation of boot wear.

Early Weightbearing Protocol in Operative Fixation of Acute Jones Fractures

The treatment of Jones fractures has been controversial in terms of nonoperative versus operative management, given the high incidence of nonunion secondary to the delicate blood supply to the proximal fifth metatarsal. We report a retrospective review of a patient cohort treated with an early weightbearing protocol after operative intramedullary fixation in acute Jones fractures. Thirty-one consecutive patients with an acute Jones fracture underwent operative fixation with a single intramedullary solid screw. The postoperative protocol consisted of immediate weightbearing in a controlled ankle motion boot for 2 weeks with a gradual transition to regular shoes at 2 weeks postoperative. At 2 weeks, the patients were allowed to perform low-impact activities such as walking, swimming, biking, or elliptical training. Patients were allowed to return to all activities, as tolerated, regardless of radiographic healing, at 6 weeks postoperatively. Serial postoperative radiographs were taken at 2-week intervals to determine radiographic union. Our patient population consisted of 24 males (77.42%) and 7 females (22.58%), with a mean average age of 37.5 ± 12.59 years and mean average body mass index of 25.7 ± 2.32 kg/m². Fracture union was observed in all 31 patients (100%) at a mean average of 5.7 ± 1.47 (range 4 to 10) weeks. Two (6.5%) patients required hardware removal, with one (3.2%) experiencing sural neuritis. This review of patients undergoing early weightbearing after operative fixation of an acute Jones fracture demonstrated a satisfactory incidence of union compared with traditional postoperative protocols at a mean follow-up duration of 18.58 ± 5.66 months.

Walking Gait Before and After Chiropractic Care Following Fifth Metatarsal Fractures: A Single Case Kinetic and Kinematic Study

Objectives

The purpose of this report is to describe the kinetic and kinematic analysis of walking gait following healed left proximal fifth metatarsal fractures.

Clinical Features

A 62-year-old female presented at a chiropractic clinic with concerns that recent metatarsal fractures had not fully resolved and reported abnormal gait due to pain and several weeks use of a "walking boot." The patient's walking gait was evaluated with a force-sensor treadmill and an inertial measurement unit motion capture system. Recordings were made before, at midpoint, and post-chiropractic care (11 visits total). Data were analyzed for spatio-temporal gait parameters, vertical ground reaction forces, and ranges of motion of the hip, knee, and ankle.

Intervention and Outcome

Pre-care, the patient's self-rated disability in walking was 50 out of 80 on a Lower Extremity Functional Scale, which improved to 80 out of 80, post-care. Her self-selected preferred walking speed increased, as did step length, cadence, and single support time. Increased symmetry was seen in timing of peak ground reaction forces, stance phase percentages of loading and pre-swing, and ranges of motion for hip and knee flexion and extension.

Conclusions

The patient recovered completely, and the post-injury kinematic and kinetic data allowed for quantification of gait patterns and changes in the clinical environment.

Effects of turf and cleat footwear on plantar load distributions in adolescent American football players during resisted pushing

Metatarsal and midfoot injuries are common in American football. Footwear design may influence injury rates by altering plantar foot loading patterns in these regions. The purpose of this study was to determine the effect of cleat design on in-shoe plantar foot loading during a football-specific, resisted pushing task. Twenty competitive football players (age 14.7 ± 1.8 years, height 1.72 ± 0.10 m, and mass 71.8 ± 26.9 kg) completed three trials of pushing a weighted sled at maximal effort in a standard shoe (CLEAT) and artificial turf-specific shoe (TURF), with flexible in-shoe force measuring insoles. Repeated measures ANOVAs identified mean differences in maximum force and relative load under all regions of the foot. Results showed higher forces in the CLEAT under the medial (p < 0.001) and lateral (p = 0.004) midfoot, central (p = 0.007) and lateral (p < 0.001) forefoot, and lesser toes (p = 0.01), but lower forces in the hallux (p = 0.02) compared to the TURF shoe. Additionally, relative loading was higher in the CLEAT under the medial (p < 0.001) and lateral (p = 0.002) midfoot and lateral (p < 0.001) forefoot, but lower in the medial forefoot (p = 0.006) and hallux (p < 0.001) compared to the TURF shoe. The two shoes elicited distinct plantar loading profiles and may influence shoe selection decisions during injury prevention or rehabilitation practices.

Zone II and III fifth metatarsal fractures in athletes

PURPOSE OF REVIEW

This study aimed to review indications, complications, and outcomes of zone II and III fifth metatarsal fractures based on recent literature.

RECENT FINDINGS

High rates of nonunion, delayed union, and refracture in athletes treated non-operatively. The standard of care is operative treatment in athletes with intramedullary fixation. Operative treatment of zone II and III fractures in athletes will decrease the risk of nonunion and refracture while leading to an earlier return to play.

Plantar pressure asymmetry and risk of stress injuries in the foot of young soccer players

BACKGROUND

Asymmetries in the magnitude of plantar pressure are considered a risk factor for stress fracture of the fifth metatarsal in soccer athletes.

OBJECTIVE

To investigate the presence of plantar pressure asymmetries among young soccer athletes.

DESIGN

Observational.

SETTING

Laboratory.

PARTICIPANTS

Thirty young adolescents divided into a soccer player group (n = 15) or a matched control group (n = 15).

MAIN OUTCOME MEASURES

Mean plantar pressure was determined for seven different regions of the foot. Data were compared between the preferred and non-preferred foot, and between the groups, during barefoot standing on a pressure mat system.

RESULTS

Higher pressure was found in the hallux, 5th metatarsal and medial rearfoot of the non-preferred foot in the young soccer players. These asymmetries were not observed in the control group. Magnitudes of plantar pressure did not differ between the groups.

CONCLUSION

Young soccer players present asymmetries in plantar pressure in the hallux, 5th metatarsal and medial rearfoot, with higher pressure observed in the non-preferred foot.

Bone Stress Injuries in Runners

Bone stress injuries (BSIs) are common running injuries and may occur at a rate of 20% annually. Both biological and biomechanical risk factors contribute to BSI. Evaluation of a runner with suspected BSI includes completing an appropriate history and physical examination. MRI grading classification for BSI has been proposed and may guide return to play. Management includes activity modification, optimizing nutrition, and addressing risk factors, including the female athlete triad. BSI prevention strategies include screening for risk factors during preparticipation evaluations, optimizing nutrition (including adequate caloric intake, calcium, and vitamin D), and promoting ball sports during childhood and adolescence.

Stress Fractures of the Foot

Stress fractures of the foot and ankle may be more common among athletes than previously reported. A low threshold for investigation is warranted and further imaging may be appropriate if initial radiographs remain inconclusive. Most of these fractures can be treated conservatively with a period of non-weight-bearing mobilization followed by gradual return to activity. Early surgery augmented by bone graft may allow athletes to return to sports earlier. Risk of delayed union, nonunion, and recurrent fracture is high. Many of the patients may also have risk factors for injury that should be modified for a successful outcome.

Treatment of Acute Jones Fractures Without Weightbearing Restriction

Jones fractures are reportedly prone to nonunion and generally treated with a period of non-weightbearing or operative treatment. Extended non-weightbearing can have adverse effects, and operative treatment poses various risks. We report the clinical results of patients treated without weightbearing restriction. All patients treated for metatarsal fractures by a single surgeon from January 1, 2000 to December 31, 2009 were identified through the clinical billing records by International Classification of Diseases, ninth revision, code. Through a radiographic and medical record review, 27 consecutive patients with acute Jones fractures treated without weightbearing restriction were identified. The demographic information and clinical and radiographic results were recorded. Of the 27 patients, 24 (89%) had achieved clinical union at a mean of 8.0 ± 2.6 weeks. Complete radiographic union was noted in 13 (48%) patients, and 13 (48%) others had made significant progress toward radiographic union but had not yet reached it. Two (8.3%) patients were lost to follow-up. One patient (4%) developed nonunion. Patients with acute Jones fractures can be treated without weightbearing restriction. This protocol results in rapid clinical union and a low rate of nonunion.

Analysis of 213 currently used rehabilitation protocols in foot and ankle fractures

INTRODUCTION

Fractures of the ankle, hind- and midfoot are amongst the five most common fractures. Besides initial operative or non-operative treatment, rehabilitation of the patients plays a crucial role for fracture union and long term functional outcome. Limited evidence is available with regard to what a rehabilitation regimen should include and what guidelines should be in place for the initial clinical course of these patients. This study therefore investigated the current rehabilitation concepts after fractures of the ankle, hind- and midfoot.

METHODS

Written rehabilitation protocols provided by orthopedic and trauma surgery institutions in terms of recommendations for weight bearing, range of motion (ROM), physiotherapy and choice of orthosis were screened and analysed. All protocols for lateral ankle fractures type AO 44A1, AO 44B1 and AO 44C1, for calcaneal fractures and fractures of the metatarsal as well as other not specific were included. Descriptive analysis was carried out and statistical analysis applied where appropriate.

RESULTS

209 rehabilitation protocols for ankle fractures type AO 44B1 and AO 44C1, 98 for AO 44A1, 193 for metatarsal fractures, 142 for calcaneal fractures, 107 for 5(th) metatarsal base fractures and 70 for 5(th) metatarsal Jones fractures were evaluated. The mean time recommended for orthosis treatment was 6.04 (SD 0.04) weeks. While the majority of protocols showed a trend towards increased weight bearing and increased ROM over time, the best consensus was noted for weight bearing recommendations.

CONCLUSION

Our study shows that there exists a huge variability in rehabilitation of fractures of the ankle-, hind- and midfoot. This may be contributed to a lack of consensus (e.g. missing publication of guidelines), individualized patient care (e.g. in fragility fractures) or lack of specialization. This study might serve as basis for prospective randomized controlled trials in order to optimize rehabilitation for these common fractures.