若年女性成人における外反母趾の機能的能力、足指屈筋力、足底圧との相関：横断的研究

Correlation between functional ability, toe flexor strength, and plantar pressure of hallux valgus in young female adults: a cross-sectional study.

• Mieko Yokozuka
• Kanako Okazaki
• Yuko Sakamoto
• Koko Takahashi

抄録

背景:

女性では、加齢に伴って口蓋外反母趾（HV）の有病率が増加する。高齢者におけるHVを含む足の問題と転倒との関係については、これまでにいくつかの研究が行われてきた。本研究では、若年女性において HV が機能活動の低下を引き起こすかどうかを検討するとともに、HV の角度、機能活動、足指屈筋力、足底圧との関係を評価した。

BACKGROUND: The prevalence of hallux valgus (HV) increases with age in females. Several studies have investigated the relationship between foot problems, including HV, and falls in older individuals. This study aimed to examine whether HV causes a decline in functional activity in young females and also evaluate the relationship between HV angle, functional activity, toe flexor strength, and plantar pressure.

方法:

下肢疾患の治療を受けていない女性94名（平均年齢19.6±1.3歳、平均体格指数21.2±2.0kg/m）を対象とした。HV角度はフットプリントを用いて決定した。機能的到達距離(FR)と最大歩幅(MSL)、足指屈筋力、足底圧を測定した。足底圧は歩行時に測定した。また、8つの領域（第1趾、第2趾から第5趾、第1中足骨、第2趾から第4趾、第5中足骨、中足部、踵内側、踵外側）のFRと足底圧を算出した。

METHODS: We assessed 94 females (mean age, 19.6 ± 1.3 years; mean body mass index, 21.2 ± 2.0 kg/m) not currently receiving treatment for lower limb disease. HV angle was determined using their footprint. Functional reach (FR) and maximum step length (MSL), toe flexor strength, and plantar pressure were measured. Plantar pressure was measured during walking. We also calculated FR and the pressure in eight regions (first toe, second through fifth toes, first metatarsal, second through fourth metatarsals, fifth metatarsal, midfoot, medial heel, and lateral heel).

結果:

HV群と無HV群の参加者はそれぞれ39人と55人であった。FRとMSLはHV群と無HV群で有意差はなかった。足指屈筋力は、HV群と無HV群で有意差があった（それぞれ26.69±9.68 vs. 32.19±8.55）（p=0.002、β=0.206）。歩行時の足底圧は、HV群では第2趾から第5趾で有意に低下した(p=0.005, β=0.187)。FR時の足底圧はHV群で第1中足骨で有意に高かった(p=0.016, β=0.338)。HV角度は、第2趾から第5趾の足指屈筋力（r=0.315, p=0.002, β=0.121）と歩行時の足底圧（r=0.362, p<0.001, β=0.047）と負の相関があり、第1中足骨のFR時の足底圧（r=0.308, p=0.002, β=0.137）と正の相関がありました。足指屈筋力は第2～第4中足骨のFR時の足底圧と負の相関があり(r=0.318, p=0.002, β=0.115)、MSLと正の相関があった(r=0.330, p=0.001, β=0.092)。

RESULTS: There were 39 and 55 participants in the HV and no HV groups, respectively. FR and MSL did not differ significantly between the HV and no HV groups. Toe flexor strength was significantly different between the HV and no HV groups (26.69 ± 9.68 vs. 32.19 ± 8.55, respectively) (p = 0.002, β = 0.206). During walking, plantar pressure was significantly lower in the second through fifth toes in the HV group (p = 0.005, β = 0.187). During FR, plantar pressure was significantly greater in the first metatarsal in the HV group (p = 0.016, β = 0.338). HV angle was negatively correlated with toe flexor strength (r = - 0.315, p = 0.002, β = 0.121) and plantar pressure during walking in the second through fifth toes (r = - 0.362, p < 0.001, β = 0.047), and positively correlated with plantar pressure during FR in the first metatarsal (r = 0.308, p = 0.002, β = 0.137). Toe flexor strength was negatively correlated with plantar pressure during FR in the second through fourth metatarsals (r = - 0.318, p = 0.002, β = 0.115), and there was a positive correlation with MSL (r = 0.330, p = 0.001, β = 0.092).

結論:

本研究では、若年女性において、HVが足指屈筋力を低下させ、歩行時やFR時の前足部圧に影響を与えることを確認しました。さらに、足指屈筋力はMSLに影響を与えた。若いうちからHVの発症・悪化を予防する努力をすることで、高齢になってからの転倒リスクを軽減できる可能性がある。

CONCLUSIONS: This study confirmed that HV reduces toe flexor strength and affects forefoot pressure during walking and FR in young females. Moreover, the toe flexor strength affects MSL. Efforts to prevent the onset and deterioration of HV from a young age might help reduce the risk of falling when older.