Functional outcome of 103 fractures of the proximal fifth metatarsal bone.

BACKGROUND: Metatarsal fractures are common skeletal injuries of the lower extremity in adults. The majority involves the proximal fifth metatarsal bone. In the current literature, there still exists controversy regarding treatment recommendations for the different fracture entities. METHODS: All patients suffering from single fractures to the proximal fifth metatarsal bone between 2003 and 2015 were enrolled in this retrospective analysis. Only patients with a minimum follow-up of 12 months were included. The fractures were classified according to Lawrence and Botte (L&B). Data were collected via patient registry, radiographs and a standardized questionnaire (Foot and Ankle Outcome Score = FOAS). For outcome analysis, the nonparametric Mann-Whitney U test was performed and Spearman's rank correlation coefficient calculated. RESULTS: In total, the functional outcomes of 103 patients suffering from fractures to the proximal fifth metatarsal bone were analyzed. L&B type I fractures (n = 13) had a FAOS score of 91 ± 23, L&B type II (n = 67) presented a score of 91 ± 15 and L&B type III (n = 23) a score of 93 ± 11. Surgically treated patients with an L&B type II fracture had no statistically significant better functional outcome in comparison to conservative management (p = 0.89). Operatively treated L&B type III fractures tended to have a better functional score (p = 0.16). The follow-up time was 58 (min: 15; max: 164) months. CONCLUSIONS: Overall, the functional outcome following fractures to the proximal fifth metatarsal bone is satisfactory. Conservatively treated L&B type II fractures showed an equivalent functional outcome compared to surgical management. Patients with an L&B type III fracture mainly were treated surgically, but difference in FAOS score did not reach level of significance.

Fifth Metatarsal Fractures in Professional Soccer Players: Case Series.

OBJECTIVE: Fifth metatarsal fractures occur mainly in young athletes, with an estimated incidence of 1.8 per 1000 individuals per year. This study aims to evaluate the functional outcome of professional soccer players undergoing surgical treatment of fifth metatarsal base fractures. METHODS: We appraised 34 soccer players operated on from July 2001 to June 2016. All individuals were assessed by the American Orthopedic Foot and Ankle Score (AOFAS) and Visual Analog Scale (VAS) before and after surgery, with a mean 23-month follow-up. The need for grafting, fracture healing, Torg classification, and return to sports were also evaluated. RESULTS: There were 10 attackers, 7 offensive-defensive midfielders, 6 side defenders, 5 central defensive midfielders, 3 defenders, 2 goalkeepers, and 1 defensive midfielder, at an average age of 19 years. Preoperative and postoperative AOFAS averaged 42 and 99 points, respectively, whereas VAS scores were 6 and 0. The longer the time to get operated on, the greater was the need for grafting (P = .011). In our study, all fractures have consolidated. Return to sports occurred, on average, 73 days after surgical treatment, and it was not influenced by the time to get operated on, fracture healing, Torg classification, and grafting. CONCLUSION: Surgical treatment of the fifth metatarsal base fracture in professional soccer players presents good clinical results. Getting back to activities after surgery is not influenced by surgery time, fracture healing, Torg classification, and grafting.Levels of Evidence: Level IV: Therapeutic studies, Case series.

Adequate union rates for the treatment of acute proximal fifth metatarsal fractures.

PURPOSE: To compare the bone healing, clinical, and return to daily activity outcomes after either surgical or conservative management of acute zone 1, 2, and 3 fifth metatarsal fractures. METHODS: A literature search was performed to identify studies published from the earliest record to January 2019 using EMBASE (Ovid), MEDLINE via PubMed, CINAHL, and Web of Science. All articles assessing clinical outcomes of acute proximal fifth metatarsal fractures were included. Bone healing and clinical outcomes were thereafter calculated using a simplified pooling method. RESULTS: Thirty-two articles comprising of a total of 1,239 fractures were included, of which one was a randomized controlled trial, seven were prospective studies, and 24 were retrospective studies. 627 zone 1 fractures demonstrated union rates of 93.2% following conservative treatment and 95.1% following surgical treatment. Conservatively managed zone 1 fractures were displaced 49.5% of the time, compared to a rate of 92.8% for the surgically treated cases. For Jones' (zone 2) fractures, bone healing outcomes of conservative versus surgical treatment showed union rates of 77.4% versus 96.3%, refracture rates of 2.4% versus 2.1%, and mean time to union of 11.0 weeks versus 9.4 weeks, respectively. Only ten proximal diaphyseal (zone 3) fractures were reported, with a mean return to work of 8.2 weeks. CONCLUSION: Acute zone 1 fractures are preferably treated conservatively as similar union rates were found after both conservative and surgical management. In contradistinction, acute zone 2 fractures demonstrate higher union rates and faster time to union when treated surgically. The outcomes of acute zone 3 fractures are rarely reported in the literature, so treatment recommendations remain unclear. Further research of proximal fifth metatarsal fractures is warranted to provide more definitive conclusions, but current findings can aid surgeons during the shared clinical decision making process. LEVEL OF EVIDENCE: IV.

Correlations between weight-bearing 3D bone architecture and dynamic plantar pressure measurements in the diabetic foot.

BACKGROUND: Measurements of plantar loading reveal foot-to-floor interaction during activity, but information on bone architecture cannot be derived. Recently, cone-beam computer tomography (CBCT) has given visual access to skeletal structures in weight-bearing. The combination of the two measures has the potential to improve clinical understanding and prevention of diabetic foot ulcers. This study explores the correlations between static 3D bone alignment and dynamic plantar loading. METHODS: Sixteen patients with diabetes were enrolled (group ALL): 15 type 1 with (N, 7) and without (D, 8) diabetic neuropathy, and 1 with latent autoimmune diabetes. CBCT foot scans were taken in single-leg upright posture. 3D bone models were obtained by image segmentation and aligned in a foot anatomical reference frame. Absolute inclination and relative orientation angles and heights of the bones were calculated. Pressure patterns were also acquired during barefoot level walking at self-selected speed, from which regional peak pressure and absolute and normalised pressure-time integral were worked out at hallux and at first, central and fifth metatarsals (LOAD variables) as averaged over five trials. Correlations with 3D alignments were searched also with arch index, contact time, age, BMI, years of disease and a neuropathy-related variable. RESULTS: Lateral and 3D angles showed the highest percentage of significant (p < 0.05) correlations with LOAD. These were weak-to-moderate in the ALL group, moderate-to-strong in N and D. LOAD under the central metatarsals showed moderate-to-strong correlation with plantarflexion of the 2nd and 3rd phalanxes in ALL and N. LOAD at the hallux increased with plantarflexion at the 3rd phalanx in ALL, at 1st phalanx in N and at 5th phalanx in D. Arch index correlated with 1st phalanx plantarflexion in ALL and D; contact time showed strong correlation with 2nd and 3rd metatarsals and with 4th phalanx dorsiflexion in D. CONCLUSION: These preliminary original measures reveal that alteration of plantar dynamic loading patterns can be accounted for peculiar structural changes of foot bones. Load under the central metatarsal heads were correlated more with inclination of the corresponding phalanxes than metatarsals. Further analyses shall detect to which extent variables play a role in the many group-specific correlations.

The coordination patterns of the foot segments in relation to lateral ankle sprain injury mechanism during unanticipated changes of direction.

Preventing lateral ankle sprain injuries (LAS) in females competing in court sports is a high priority, as an athlete's risk for re-injury and developing long term dysfunction increases significantly after sustaining an acute LAS. Stability to the ankle joint is passively provided by the joint congruity and ligaments, and actively by the muscles acting on the foot. The ankle joint is most stable when loaded and dorsiflexed. However, during unanticipated changes of direction, typical in court sports, the foot is often in a vulnerable unloaded, plantarflexed position. Stability of the forefoot and controlling rearfoot movement to avoid excessive ankle inversion and adduction thus becomes imperative. Information regarding the coupling relationship between the forefoot (hallux and metatarsal segments) and the rearfoot (calcaneus segment) during unanticipated changes of direction is lacking. The aim of this study was to supplement current LAS prophylactic knowledge by describing and quantifying hallux-calcaneus and metatarsal-calcaneus coupling. The coupling angles between sagittal plane hallux, tri-planar metatarsal and frontal- and transverse plane calcaneus movement, respectively, were calculated with a modified vector coding technique which used segmental velocities in a local, anatomical reference frame instead of segmental angles in a global reference frame. Coupling relationships revealed anti-phase movement between sagittal- metatarsal and frontal plane calcaneus movement throughout stance. During loading, sagittal- and frontal plane metatarsal acceleration/deceleration were coupled with frontal-transverse plane calcaneus acceleration/deceleration respectively. The remainder of the braking phase was characterized by calcaneus eversion deceleration. During propulsion, the hallux and metatarsal segments increased plantar flexion velocity in response to calcaneus inversion and adduction acceleration. As the forefoot was the only point of contact during stance, the coupling between segments were most likely neuromuscular. Strengthening intrinsic and extrinsic foot muscles may thus contribute to foot and ankle stability, adding to current prophylactic LAS strategies.

Effects of metatarsal domes on plantar pressures in older people with a history of forefoot pain.

BACKGROUND: Forefoot pads such as metatarsal domes are commonly used in clinical practice for the treatment of pressure-related forefoot pain, however evidence for their effects is inconsistent. This study aimed to evaluate the effects on plantar pressures of metatarsal domes in different positions relative to the metatarsal heads. METHODS: Participants in this study included 36 community-dwelling adults aged 65 or older with a history of forefoot pain. Standardised footwear was used and plantar pressures were measured using the pedar®-X in-shoe plantar pressure measurement system. Peak pressure, maximum force and contact area were analysed using an anatomically-based masking protocol that included three forefoot mask sub-areas (proximal to, beneath, and distal to the metatarsal heads). Data were collected for two different types of prefabricated metatarsal domes of different densities (Emsold metatarsal dome and Langer PPT metatarsal pad) in three different positions relative to the metatarsal heads. Seven conditions were tested in this study: (i) control (no pad) condition, (ii) Emsold metatarsal dome positioned 5 mm proximal to the metatarsal heads, (iii) Emsold metatarsal dome positioned in-line with the metatarsal heads, (iv), Emsold metatarsal dome positioned 5 mm distal to the metatarsal heads, (v) Langer PPT metatarsal pad positioned 5 mm proximal to the metatarsal heads, (vi) Langer PPT metatarsal pad positioned in-line with the metatarsal heads, and (vii) Langer PPT metatarsal pad positioned 5 mm distal to the metatarsal heads. RESULTS: When analysed with the mask that was distal to the metatarsal heads, where the plantar pressure readings were at their highest, all metatarsal dome conditions led to significant reductions in plantar pressure at the forefoot compared to the control (no pad) condition (F3.9, 135.6 = 8.125, p < 0.001). The reductions in plantar pressure were in the order of 45-60 kPa. Both the Emsold metatarsal dome and the Langer PPT metatarsal pad, when positioned proximal to the metatarsal heads, managed to achieve this without adversely increasing plantar pressure proximally where the pad was positioned, however the Emsold metatarsal dome was most effective. CONCLUSIONS: Metatarsal domes reduce plantar pressure in the forefoot in older people with a history of forefoot pain. All metatarsal dome conditions significantly reduced peak pressure in the forefoot, however metatarsal domes that were positioned 5 mm proximal to the metatarsal heads provided the best balance of reducing plantar pressure distal to the metatarsal heads, where the pressure is at its greatest, but not adversely increasing plantar pressure proximally, where the bulk of the pad is positioned. In this proximal position, the Emsold metatarsal dome was more effective than the Langer PPT metatarsal pad and we cautiously recommend this forefoot pad for alleviating forefoot pressure in older people with forefoot pain.

The Biomechanical Relationship between Hallux Valgus Deformity and Metatarsal Pain.

Metatarsal pain is a common pathological outcome in patients with a hallux valgus (HV) deformity. However, the relationship between the degree of HV deformity and metatarsal pain has not been systematically examined. The purpose of the present study was to investigate the correlation between metatarsal pain and the degree of HV deformity. Between October 2017 and September 2018, 512 HV patients (944 feet) participated in an evaluation of their HV angle (HVA) using X-ray images. The participants were divided into four groups corresponding to their HVA (<15°, 15° to 20°, 21° to 40°, or >40°). Load rate, impulse, contact duration, and contact area were measured and recorded as dynamic gait parameters using the RsScan system. Data were evaluated using SPSS statistical software. The visual analog scale (VAS) was used to assess metatarsal pain. For the four HV deformity groups, the peak value of impulse and contact duration was concentrated on the second and third metatarsals (Meta2 and Meta3) (P < 0.05); contact area was also shown on metatarsals 1, 2, and 5 (P < 0.05). Metatarsal pain on Meta2 had the highest VAS score (VAS: 6.57), followed by Meta3 (Mean VAS: 5.72). In the HV > 40° group, the load location on Meta2 was transferred to Meta1. The percent of pain attributed to Meta2 and Meta3 was also increased in this group. These findings illustrated that metatarsal pain was primarily located on Meta2 and Meta3 in the different degrees of HV deformity. This information can provide the location to target for pain relief and help guide further rehabilitation.

Bizarre parosteal osteochondromatous proliferation co-occurring with a metatarsal fatigue fracture: a case report.

BACKGROUND: Bizarre parosteal osteochondromatous proliferation (BPOP) is a relatively rare benign extraperiosteal osteochondroma-like proliferative lesion that shares similarities with malignant tumours in terms of morphology. The aetiology of BPOP has yet to be determined and there are no previous reports of BPOP associated with fracture. CASE PRESENTATION: A 57-year-old woman presented with a one-month history of pain and swelling in her right foot, which were worsened by activity and improved with rest. Physical examination revealed a hard, non-mobile mass measuring 1.5 cm × 1.5 cm on the dorsal aspect of the third metatarsal of the right foot. There was overlying erythema and tenderness on palpation. Computed tomography (CT) of the right foot demonstrated a fracture of the neck of the third metatarsal, osteolysis at the fracture site and soft tissue swelling. Bone scintigraphy revealed increased tracer uptake suggesting abnormal bone metabolism at the neck of the third metatarsal. Surgical excision of the lesion was performed. Histopathology and immunohistochemistry confirmed the diagnosis of BPOP. CONCLUSION: BPOP is a rare benign lesion that is commonly misdiagnosed. Differential diagnosis is mainly achieved through imaging and histopathological assessment.

PAPPI: Personalized analysis of plantar pressure images using statistical modelling and parametric mapping.

Quantitative analyses of plantar pressure images typically occur at the group level and under the assumption that individuals within each group display homogeneous pressure patterns. When this assumption does not hold, a personalized analysis technique is required. Yet, existing personalized plantar pressure analysis techniques work at the image level, leading to results that can be unintuitive and difficult to interpret. To address these limitations, we introduce PAPPI: the Personalized Analysis of Plantar Pressure Images. PAPPI is built around the statistical modelling of the relationship between plantar pressures in healthy controls and their demographic characteristics. This statistical model then serves as the healthy baseline to which an individual's real plantar pressures are compared using statistical parametric mapping. As a proof-of-concept, we evaluated PAPPI on a cohort of 50 hallux valgus patients. PAPPI showed that plantar pressures from hallux valgus patients did not have a single, homogeneous pattern, but instead, 5 abnormal pressure patterns were observed in sections of this population. When comparing these patterns to foot pain scores (i.e. Foot Function Index, Manchester-Oxford Foot Questionnaire) and radiographic hallux angle measurements, we observed that patients with increased pressure under metatarsal 1 reported less foot pain than other patients in the cohort, while patients with abnormal pressures in the heel showed more severe hallux valgus angles and more foot pain. Also, incidences of pes planus were higher in our hallux valgus cohort compared to the modelled healthy controls. PAPPI helped to clarify recent discrepancies in group-level plantar pressure studies and showed its unique ability to produce quantitative, interpretable, and personalized analyses for plantar pressure images.

Detailed analysis of the transverse arch of hallux valgus feet with and without pain using weightbearing ultrasound imaging and precise force sensors.

BACKGROUND: Hallux valgus is the most common forefoot deformity and affects the transverse arch structure and its force loading patterns. This study aims to clarify the differences in the transverse arch structure and the force under the metatarsal heads individually, between normal feet and hallux valgus feet, and between hallux valgus feet with pain and without pain. We further test the association between the parameters of the transverse arch and hallux valgus angle and between the parameters and pain in hallux valgus. METHODS: Women's feet (105 feet) were divided into normal group (NORM) and hallux valgus group (HVG); and further into subgroups: hallux valgus without pain (HV Pain (-)) and hallux valgus with pain (HV Pain (+)). Transverse arch height and metatarsal heads height were measured using weight-bearing ultrasound imaging. Force under the metatarsal heads was measured using force sensors attached directly on the skin surface of the metatarsal heads. The measurements were taken in three loading positions: sitting, quiet standing and 90% weight shift on the tested foot. Differences between the groups were compared using Student t-test and Wilcoxon Exact test. Multivariate logistic analysis with adjustment for physical characteristics was also conducted. RESULTS: Transverse arch height was significantly higher in HVG than in NORM in all positions; there were no significant differences between HV Pain (+) and HV pain (-). Lateral sesamoid was significantly higher in HVG and HV Pain (+) than in NORM and HV Pain (-) respectively when bearing 90% of the body weight unilaterally. There was a trend of higher forces under the medial forefoot without significant difference. Transverse arch height and lateral sesamoid height were associated with the hallux valgus angle, while lateral sesamoid height was associated with forefoot pain in hallux valgus deformity. CONCLUSIONS: This study shows the differences in the transverse arch structure between normal feet and feet with hallux valgus, and between hallux valgus feet with and without pain. This finding is noteworthy when considering future treatments of painful feet, notably the height of the lateral sesamoid which seems to play a role in forefoot pain.

Effect of the Modified Lapidus Procedure on Pronation of the First Ray in Hallux Valgus.

BACKGROUND: Hallux valgus (HV) is a triplanar deformity of the first ray including pronation of the first metatarsal with subluxation of the sesamoids. The purpose of this study was to investigate if a first tarsometatarsal fusion (modified Lapidus technique), without preoperative knowledge of pronation measured on weightbearing computed tomographic (CT) scans, changed pronation of the first metatarsal and determine if reduction of the sesamoids was correlated with changes in first metatarsal pronation. METHODS: Thirty-one feet in 31 patients with HV who underwent a modified Lapidus procedure had preoperative and at least 5-month postoperative weightbearing CT scans and radiographs. Differences in preoperative and postoperative pronation of the first metatarsal using a 3-dimensional computer-aided design, HV angle, and intermetatarsal angle (IMA) were calculated using Wilcoxon signed-rank tests. After dividing patients into groups based on sesamoid station, Kruskal-Wallis H tests were used to compare first metatarsal pronation between the groups. RESULTS: The mean preoperative and postoperative pronation of the first metatarsal was 29.0 degrees (range 15.8-51.1, SD 8.7) and 20.2 degrees (range 10.4-32.6, SD 5.4), respectively, which was a mean change in pronation of the first ray of -8.8 degrees (P < .001). There was no difference in pronation of the first ray when stratified by postoperative sesamoid position (P > .250). The average preoperative and postoperative IMA was 16.7 degrees (SD 3.2) and 8.8 degrees (SD 2.8), which demonstrated a significant change (P < .001). CONCLUSIONS: The modified Lapidus procedure was an effective tool to change pronation of the first ray. Reduction of the sesamoids was not associated with postoperative first metatarsal pronation. LEVEL OF EVIDENCE: Level IV, case series.

Radiological Evaluation of a Preoperative First Metatarsal Realignment Test for Metatarsus Primus Varus and Hallux Valgus Correction by the Syndesmosis Procedure.

BACKGROUND: Metatarsus primus varus correction is one of the primary surgical objectives for hallux valgus correction. Some soft tissue procedures have shown that the first metatarsal can be adequately realigned without osteotomy. The hypothesis of this study was that this correctability should also be demonstrable preoperatively. The purpose of this study was to assess whether a simple forefoot taping technique could do so and whether it could also be correlated with operative results after the syndesmosis procedure. METHODS: Between May 2014 and December 2015, 147 feet with hallux valgus from 85 patients with an average age of 46.2 years underwent the syndesmosis procedure. All were followed prospectively with standing radiographic assessment of their first intermetatarsal angle, metatarsophalangeal angle, and medial sesamoid position preoperatively without and with a forefoot wrapping technique and postoperatively at 10 days, 6 months, and 1 year. RESULTS: Their average preoperative intermetatarsal angle was reduced from 14.4 to 8.4 degrees by the wrapping technique, and their average metatarsophalangeal angle was spontaneously reduced from 31.8 to 21.8 degrees. After a minimum 1-year follow-up, they stabilized at 7.4 and 18.6 degrees, respectively. There was significant correlation between hallux valgus and metatarsus primus varus corrections by both forefoot wrapping and surgical methods with Spearman's rank correlation of metatarsophalangeal angle and intermetatarsal angle corrections (r = 0.6077, P < .0001 due to the wrapping method; r = 0.7157, P < .0001 due to the syndesmosis procedure). All raw working radiographic images for this study can be viewed in the Supplemental Material section. CONCLUSION: This study found that a simple forefoot tape-wrapping technique could be used preoperatively to verify first metatarsal mobility for metatarsus primus varus correction by the soft tissue syndesmosis procedure without osteotomies. LEVEL OF EVIDENCE: Level II, prospective comparative study.

Mechanical Basis of Metatarsalgia.

The 3-rocker mechanism of gait provides a framework to understand why patients have mechanical metatarsal pain and to differentiate between the various types of metatarsalgia. Clinical examination of the patient together with radiological findings allows identification of the type of metatarsalgia and the pathomechanics involved, and the planning of surgical treatment. Second-rocker/nonpropulsive metatarsalgia is related with an abnormal inclination of a metatarsal in the sagittal plane, either anatomic or functional (equinism). Third-rocker/propulsive metatarsalgia is related to an abnormal length of a certain metatarsal with respect to the neighboring metatarsals in the transverse plane.

Ligamentous Lisfranc Injury: A Biomechanical Comparison of Dorsal Plate Fixation and Transarticular Screws.

OBJECTIVES: Optimal fixation technique after purely ligamentous Lisfranc injury remains controversial. This biomechanical study compares dorsal plate versus transarticular screw fixation by measuring dorsal and plantar joint diastasis. A unique protocol was developed, using reflective triad markers and positional cameras. METHODS: Eleven cadaveric matched pairs were assigned to either transarticular screw or dorsal plate fixation. Two reflective triad markers were placed into the medial cuneiform (C1) and second metatarsal base (MT2). Three cameras recorded the 3-dimensional location of triads to quantify C1-MT2 diastasis in the following states: intact Lisfranc ligament (INTACT), cut ligament (CUT), fixed (SCREW or PLATE) joint, and fixed joint after 10,000 loaded cycles. On completion, the plantar Lisfranc ligament insertions were identified, and plantar diastasis was determined using additional reflective triads. Statistical post hoc pairwise comparisons assessed differences in diastasis. RESULTS: C1-MT2 diastasis in the CUT state increased relative to INTACT (P < 0.001). SCREW fixation reduced C1-MT2 diastasis relative to CUT at dorsal (P < 0.007) and plantar (P = 0.015) locations after cycling. PLATE fixation significantly reduced dorsal diastasis relative to CUT (P < 0.001) but not for plantar diastasis (P > 0.99). PLATE plantar diastasis was numerically higher than INTACT but not significantly (P > 0.39). PLATE plantar diastasis tended to be greater than SCREW before cycling (P = 0.068) and after cycling (P = 0.080). CONCLUSIONS: Transection of the Lisfranc ligament complex yielded C1-MT2 diastasis. Both SCREW and PLATE fixation successfully reduced dorsal diastasis. However, upon load, the PLATE resulted in greater plantar diastasis, nearly statistically different relative to the SCREW. Cyclic loading at 343 N did not worsen diastasis.

Transfer of plantar pressure from the medial to the central forefoot in patients with hallux valgus.

BACKGROUND: The aim of the study was to evaluate changes in plantar pressure distribution in feet affected by hallux valgus compared with their contralateral non-affected feet and with the feet of healthy control subjects. METHODS: Thirty-six patients with unilateral hallux valgus who were indicated for surgery and 30 healthy subjects were assessed on a pedobarographic instrumented treadmill for step length and width, mean stance phase, and plantar foot pressure distribution. Plantar pressure distribution was divided into eight regions. RESULTS: Significantly higher plantar pressures were observed in hallux valgus feet under the second and third metatarsal heads (p = .033) and the fourth and fifth toes (p < .001) than in the healthy control feet. Although decreased pressures were measured under the hallux in affected feet (197 [82-467] kPa) in contrast to the contralateral side (221 [89-514] kPa), this difference failed to reach statistical significance (p = .055). The gait parameters step width, step length, and single-limb support did not show any differences between hallux valgus and control feet. CONCLUSION: Although the literature on changes in plantar pressures in hallux valgus remains divided, our findings on transferring load from the painful medial to the central and lateral forefoot region are consistent with the development of transfer metatarsalgia in patients with hallux valgus.

Biomechanical comparison of fixation stability using a Lisfranc plate versus transarticular screws.

BACKGROUND: To obtain adequate fixation in treating Lisfranc soft tissue injuries, the joint is commonly stabilized using multiple transarticular screws; however iatrogenic injury is a concern. Alternatively, two parallel, longitudinally placed plates, can be used to stabilize the 1st and 2nd tarsometatarsal joints; however this may not provide adequate stability along the Lisfranc ligament. Several biomechanical studies have compared earlier methods of fixation using plates to the standard transarticular screw fixation method, highlighting the potential issue of transverse stability using plates. A novel dorsal plate is introduced, intended to provide transverse and longitudinal stability, without injury to the articular cartilage. METHODS: A biomechanical cadaver model was developed to compare the fixation stability of a novel Lisfranc plate to that of traditional fixation, using transarticular screws. Thirteen pairs of cadaveric specimens were tested intact, after a simulated Lisfranc injury, and then following implant fixation, using one method of fixation randomly assigned, on either side of each pair. Optical motion tracking was used to measure the motion between each of the following four bones: 1st metatarsal, 2nd metatarsal, 1st cuneiform, and 2nd cuneiform. Testing included both cyclic abduction loading and cyclic axial loading. RESULTS: Both the Lisfranc plate and screw fixation method provided stability such that the average 3D motions across the Lisfranc joint (between 2nd metatarsal and 1st cuneiform), were between 0.2 and 0.4mm under cyclic abduction loading, and between 0.4 and 0.5mm under cyclic axial loading. Comparing the stability of fixation between the Lisfranc plate and the screws, the differences in motion were all 0.3mm or lower, with no clinically significant differences (p>0.16). CONCLUSIONS: Diastasis at the Lisfranc joint following fixation with a novel plate or transarticular screw fixation were comparable. Therefore, the Lisfranc plate may provide adequate support without risk of iatrogenic injury to the articular cartilage.

The value of axial loading three dimensional (3D) CT as a substitute for full weightbearing (standing) 3D CT: Comparison of reproducibility according to degree of load.

BACKGROUND: Full weightbearing (WB) three dimensional computed tomography (3D CT) is an excellent imaging tool. However, due to its high cost, it is only used in a few hospitals. We evaluated the usefulness and cost-effectiveness of axial loading (AL) 3D CT by comparing bony alignments with standing radiographs, and assessed reproducibility according to the degree of AL. METHODS: Eighty patients (156 feet), who underwent standing radiographs and 3D CT with an AL device from January 2016 to May 2017, were investigated. According to the degree of AL (AL force×100/body weight), the patients were randomly assigned to three groups: Group A (30-50%; n=21, 40 feet), Group B (50-70%; n=32, 63 feet), and Group C (70-100%; n=27, 53 feet). The following angles were measured three times by two orthopedists: hallux valgus (HVA), 1st-2nd intermetatarsal (IMA1-2), and talo-navicular coverage (TNCA), calcaneal pitch (CPA), talo-1st metatarsal (T1MA), and talo-calcaneal angle (TCA). Agreements between the two imaging methods were analyzed and compared according to the degree of axial loading in each group. RESULTS: Intra- and interobserver reliability was excellent (>0.75). In Group A (30-50% AL), all of the angles except HVA and IMA1-2 differed (p<.05). In Group B (50-70%), TNCA (p=.023), T1MA (p=.017), and TCA (p=.035) differed. In Group C (70-100%), none of the angles differed between the two imaging methods (p>.05). Higher agreement between the two imaging methods was realized when 70% or more(>70%) AL was applied. CONCLUSIONS: AL 3D CT with >70% axial load has full WB effects and can be substituted for expensive full WB 3D CT.

Radiographic Evaluation of First Metatarsal and Medial Cuneiform Morphology in Juvenile Hallux Valgus.

BACKGROUND: Operative treatment of juvenile hallux valgus (JHV) has a high recurrence rate. The aim of this study was to better understand the pattern of radiographic deformity. METHODS: Standing radiographs of 93 feet in 57 patients with JHV, and 50 feet in 36 normal patients were measured. Measurements included: hallux valgus angle (HVA), first metatarsal physis status (open or closed), intermetatarsal angle (IMA), distal metatarsal articular angle (DMAA), Meary's angle, medial cuneiform angle (MCA), relative first to second metatarsal length ratio (1:2 MT ratio), cuneiform obliquity (CO), and congruency of the metatarsophalangeal joint (MTPJ). JHV groups were defined as normal (HVA 0-15 degrees), mild-moderate (HVA 15-35), or severe (HVA > 35) and were analyzed. RESULTS: Seventy of 93 feet (75%) with JHV presented with mild-moderate JHV (average HVA of 26.2 ± 5.6 degrees), and 23 feet (25%, 23/93) presented with severe JHV (average HVA of 41.9 ± 5.3 degrees). Multivariable analysis determined that DMAA ( P < .001), MCA ( P = .04), and congruency ( P < .001) were independently associated with JHV and its severity (normal vs mild-moderate vs severe). Severe JHV cases had larger DMAA ( P = .01), larger IMA ( P = .01), larger 1:2 MT ratio ( P = .02), and were less frequently congruent ( P = .03) compared with mild-moderate JHV cases. CONCLUSION: Deformity in JHV was highly correlated with both the proximal and distal morphology of the first metatarsal and medial cuneiform. Severe JHV was associated with increased bony deformity and increased incongruity of the MTPJ. Treatment should be individualized, but JHV treatment algorithms can take this information into account. LEVEL OF EVIDENCE: Level III, comparative study.

An anatomically-based masking protocol for the assessment of in-shoe plantar pressure measurement of the forefoot.

BACKGROUND: The area beneath the metatarsal heads is a common location of foot pain, which is often associated with high plantar pressures. Current plantar pressure assessment protocols focus mainly on the gross area of the forefoot with minimal attention paid to specific areas such as the metatarsal heads. The aim of this study was to develop and assess a new anatomically-based masking protocol that is clinically relevant to measure forefoot plantar pressure during shod conditions based on the anatomical positions of the metatarsal heads. METHODS: Initially, we developed a masking protocol to measure forefoot plantar pressure during shod conditions based on the anatomical positions of the metatarsal heads. This new masking protocol divided the forefoot into three sub-areas (proximal, beneath, and distal to the metatarsal heads) as determined by the position of each metatarsal head. Following development of the new masking protocol, we compared the new protocol against a traditional protocol, which defines the forefoot as between 51 and 81% of the foot length. To compare the two masking protocols, we tested two experimental conditions: (i) a control condition (i.e. no metatarsal pad), and (ii) a metatarsal pad condition. We then compared plantar pressure differences between the two experimental conditions for the two masking protocols. Participants for this component of the study included 36 community dwelling older adults (mean age 75.6 years ±5.4) with a history of forefoot pain. Forefoot plantar pressure data were measured while walking using the pedar®-X in-shoe system. Peak pressure, maximum force and contact area at the time of peak pressure were determined and results were compared between the two masking protocols. RESULTS: The traditional masking protocol showed that the metatarsal pad significantly decreased peak pressure and increased contact area in the forefoot area (i.e. within the entire mask area), but maximum force was not significantly different between the two conditions. In contrast, the newly developed anatomically-based masking protocol indicated that the metatarsal pad decreased peak plantar pressures distal to and beneath the metatarsal heads by increasing force and contact area proximal to the metatarsal heads. CONCLUSIONS: An anatomically-based masking protocol that is clinically relevant was developed to assess forefoot plantar pressure during shod conditions based on the anatomical positions of metatarsal heads. We propose that the new forefoot masking protocol will provide greater interpretability of forefoot plantar pressure data, which will aid clinicians and researchers for diagnostic, prognostic and therapeutic purposes.

Effects of severe hallux valgus on metatarsal stress and the metatarsophalangeal loading during balanced standing: A finite element analysis.

The internal stress of the human foot enables efficient parametric evaluation of structural and functional impairments associated with foot deformities, such as hallux valgus (HV). However, the status of the internal stress of such a deformed foot remains insufficiently addressed due to the difficulties and limitations of experimental approaches. This study, using finite element (FE) methodology, investigated the influence of severe HV deformity on the metatarsal stress and the metatarsophalangeal (MTP) joint loading during balanced standing. FE models of a normal foot and a severe HV were constructed and validated. Each FE model involves 28 bones and various cartilaginous structures, ligaments, and plantar fascia, as well as encapsulated soft tissue. All the materials except for the encapsulated soft tissue were considered isotropic and linearly elastic, while the encapsulated soft tissue was set as nonlinear hyperelastic. Hexahedral elements were assigned to the solid parts of bones, cartilage, and the encapsulated soft tissue. Link elements were assigned to ligaments and plantar fascia. A plate was created for simulating ground support. A vertical force of a half-body weight was applied on the bottom of the plate for simulating balanced standing loading. The superior surfaces of the encapsulated soft tissue, distal tibia, and distal fibula were fixed. Stress distribution in the metatarsals, contact pressure, and force at the MTP joints were comparatively analysed. Compared to the normal foot, the HV foot showed higher stress concentration in the metatarsals but lower magnitude of MTP joint loading. In addition, the region with high contact pressure at the first MTP joint shifted medially in the HV foot. Knowledge of this study indicates that patients with severe HV deformity are at higher risk of metatarsal injuries and functional impairment of the MTP joints while weight bearing.