First Metatarsal Head Research Articles

Bone Density of the First Metatarsal Head: Which is the Best Place to Put the Screws in MIS Hallux Valgus Surgery?

Category: Basic Sciences/Biologics; Bunion Introduction/Purpose: Hallux valgus minimally invasive surgery (MIS) is becoming more common due to its good clinical and functional results. Third-generation MIS surgery uses screw fixation that is dependent on the bone density of the first metatarsal head (FMH) for optimal screw purchase. There is no information regarding areas of higher bone density (BMD) in the FMH that suggest a stronger area of fixation, nor has it been described whether it varies between different age groups or with gender. The objective of this study is to determine the BMD within four quadrants of the FMH. This finding could lead to identifying the ideal trajectory for screw placement. In addition, we evaluate BMD variation by age and gender. Methods: Transversal study. From our CT scan database, we obtained 40 patients with no previous history of first metatarsal fractures, pre existing hardware, foot surgery or osteoporosis. We divided the patients into 4 groups, each group containing 5 male and 5 female patients: group 1: <30 years, group 2: 31-45 years, group 3: 46-60 years, group 4: > 60 years. The main outcome is to evaluate the association between BMD in each FMH quadrant. Secondary outcomes are to identify any differences in BMD between gender and age groups. According to what has been previously discussed in the literature, two evaluators measured the Hounsfield units (HU) of each quadrant on a coronal cut located 10 mm proximal to the metatarsophalangeal joint using the Merge PACS system. Measures were averaged. Statistical analysis was performed by measuring normality with the Shapiro-Wilks test, and the ANOVA, Student's t-test, and Mann-Whitney U test. Results: The dorsolateral (DL) quadrant had the highest BMD (353.9hu) of all quadrants, followed by the lateral plantar (LP: 302.4hu), medial plantar (MP: 264.1hu), and dorsomedial (DM: 247.6hu) (p=0.001).When comparing the groups by age, DL (p=0.01) and LP (p=0.01) quadrants had significantly greater BMD in groups 1 and 2 (< 45 years) than groups 3 and 4 (> 45 years).When comparing BMD by gender, differences were only obtained in the group 4, in which mens had greater BMD in the DM (p=0.03), DL (p=0.02), and LP (p=0.01) quadrants.An significant inverse association between age and BMD was obtained for the DL (P=0.004) and MP (P=0.03) quadrants. Conclusion: There are differences in BMD between the quadrants of the first metatarsal head, with the greatest BMD being in the dorsolateral region at any age. BMD decreased proportionally with increasing age in the DL and MP quadrants. At the same age, there are no significant differences between gender, except in patients >60 years, where women have lower BMD in almost all quadrants.

Reconstructing the First Metatarsophalangeal Joint of Homo naledi.

The aim of the present study was to develop a new method to reconstruct damaged metatarsophalangeal joint (MTPJ) of Homo naledi's fossil and to deepen the understanding of the first metatarsal head (FMH) morphological adaptation in different gait patterns. To this purpose three methods were introduced. The first served to compare the anthropometric linear and volumetric measurements of Homo naledi's MTPJ to that of 10 various athletes. The second was employed to measure curvature diameter in FMH's medial and lateral grooves for sesamoid bones. The third was used to determine the parallelism between medial and lateral FMH grooves. The anthropometric measurements of middle-distance runner to the greatest extent mimicked that of Homo naledi. Thus, it was used to successfully reconstruct the damaged Homo naledi's MTPJ. The highest curvature diameter of medial FMH groove was found in Homo naledi, while in lateral FMH groove it was the highest in volleyball player, suggesting their increased bear loading. The parallelism of medial and lateral FMH grooves was observed only in Homo naledi, while in investigated athletes it was dis-parallel. Athletes' dis-paralleled structures make first MTPJ simple flexion movement a complicated one: not rotating about one axis, but about many, which may result in bringing a negative effect on running. In conclusion, the presented method for the reconstruction of the damaged foot bone paves the way for morphological and structural analysis of modern population and fossil hominins' gait pattern.

Effect of shoes cleat position on physiological and biomechanical variables of cycling performance

Introduction: The cleat under the cycling shoe is generally positioned below the first metatarsal head, directly over the pedal axis (Silberman et al., 2005, Clinical Journal of Sport Medicine, 15, 271-276). Previous studies did not found significant change of oxygen consumption (VO2) with moving forward or backward the cleat position (Van Sickle & Hull, 2007, Journal of Biomechanics, 40, 1262-1267; Paton, 2009, International Journal of Sports Physiology and Performance, 4, 517-523) although small changes in electromyography (EMG) activity in leg and thigh muscles have been observed (Ericson et al., 1985, Scandinavian Journal of Rehabilitation Medicine, 17, 53-61; Litzenberger et al., 2008, The Engineering of Sport 7, 1, 215-222). However, these changes have been observed with non cyclist subjects for larger shoe cleat displacements (+ 50 mm).  Purpose: The aim of this study was to investigate the acute effects of small variation of cleat position on the energy cost and pedalling technique (kinetics, kinematics and electromyography) during submaximal cycling. The second purpose was to analyze their effects on supramaximal cycling performance.  Methods: Twelve cyclists participated (25 ± 6 years; 69 ± 7 kg; 1.78 ± 0.05 m; Maximal Aerobic Power: 406 ± 40 W), being amateur and elite cyclists, according to previous conventions (Ansley and Cangley, 2009, European Journal of Sport Science, 9(2), 61-85). They performed three 5-min submaximal pedalling exercises (35, 50 and 65% MAP) and one 10-s supramaximal test (sprint) on Lode Excalibur electromagnetically braked cycle ergometer (Lode B. V., Groningen, The Netherlands). Three different cleat positions were studied in a randomized order: under the first metatarsal head, 15 mm forward and 15 mm backward. Power output, oxygen consumption, kinematics of lower limb joints and surface EMG activity (EMG) of six lower limb muscles (rectus femoris: RF, vastus lateralis: VL, biceps femoris: BF, tibialis anterior: TA, gastrocnemius lateralis: GL, soleus: SOL) were recorded during all the pedalling exercises, at 1, breath-by-breath, 200 and 1000 Hz, respectively. The kinematics and RMS over whole crank cycle of EMG activity were computed during 30 consecutives pedalling cycles. One-way ANOVA for repeated measures was performed to analyse the effect of cleat position on biomechanical and physiological variables.   Results and Discussion: Hip ROM was lower in forward position and ankle ROM was lower in backward position compared to the metatarsal position (Figure 1). None significant differences between the three cleat positions were found for knee ROM and RMS despite trends can be observed in backward position for SOL and GL activity to decrease and for RF and TA activity to increase. These tendencies are consistent with previous studies (Ericson et al., 1985; Litzenberger et al., 2008). Like in previous studies (Van Sickle & Hull, 2007; Paton, 2009), small changes of cleat position had no significant effects on VO2, nor on gross efficiency (19.9 ± 1.9 % ; 19.5 ± 2.1 % ;19.4 ± 2.0 % respectively for forward, metatarsal and backward cleat positions). No significant differences in peak power output were found during the supramaximal test between forward (18.9 ± 3.2 W.kg-1), metatarsal (19.0 ± 3.4 W.kg-1) and backward (19.0 ± 2.9 W.kg-1) cleat positions.  To conclude, the main finding of this study is that small changes of cleat position (± 15 mm) involve slight changes of kinematic of the hip and ankle joints without altering cycling efficiency and maximal power output during supramaximal sprints. Although muscular activity level remains unchanged by variation ± 15 mm of cleat position, these results should be completed by the analysis of the muscle timing activation.

Distal pedical fibular osteoseptocutaneous flap transfer for the lateral forefoot defect

Objective The anterior-lateral defect of foot that lost one of the three supporting point of foot can lead to collapse of the lateral longitudinal arch, overload of the first metatarsal heads, and painful callus formation. It is meaningful to investigate the effect of reconstructing the lateral forefoot defect with pedical fibular osteoseptocutaneous flap. Methods From March 1989 to June 2008, there were 38 patients with anterior-lateral defect of foot were constructed. The supporting point with the local distal based pedical fibular osteoseptocutaneous flap was constracted. Results All the 38 flaps survived. All 38 patients had been followed up from 6 months to 10 years (mean 23.5 months) postoperatively. The constructed supporting point of the foot was functional. The patients could walk freely with no pain, and was satisfied with the operation. Assessed with the rating system for foot and ankle established by the American Orthopaedic Foot And Anke Society, 8 patients got a score above 85, 23 patients between 75 to 85, 7 patients between 60 to 75. Conclusion It is effective that transferring local distal based pedical fibular osteoseptocutaneous flap to repair the anterior-lateral defect of foot. Key words: Forefoot; Distal pedical fibular osteoseptocutaneous flaps; Transplantation; Microsurgery

Surgical treatment of the first metatarsal fractures

Objective To explore the operative methods for the first metatarsal fractures. Methods From January 2003 to January 2006, surgical operation was done on 17 patients with the first metatarsal fractures including 15 males and two females at average age of 40.5 years (11-65 years). There were four patients with the first metatarsal base fractures, seven with the first metatarsal shift frac-tures and six with the first metatarsal neck or head fractures, of whom four were with open fractures. The surgical treatment included open reduction, plate internal fixation and screw or K-wire fixation. Results Of all, 14 patients were followed up for average 14 months ( 12-24 months), which showed wound healing at one stage, without any complications. The bone union time was 8-16 weeks (mean 10.5 weeks). All patients could walk with weight loading after mean 13 weeks (9-18 weeks), without obvious pain or com-plaints. According to the midfoot and forefoot scale of American Orthopedic Foot and Ankle Society (AOFAS), the mean score was 86.3 points (78-100 points). Conclusion Anatomic reduction and stable internal fixation is the best solution for the first metatarsal fracture and plays important role in recovery of foot form and foot arch function. Key words: Metatarsal bones; Fracture fixation, internal

Hallux valgus: further considerations--the first metatarsal head.

Hallux valgus: further considerations--the first metatarsal head.