Abstract:

Objective

To explore the role of lower extremity biomechanical evaluation in foot and ankle disease.

Methods

360 patients suspected of foot and ankle disease in Hengshui Second People's Hospital were analyzed retrospectively.All patients were classified according to suspected disease types： Group A（ankle fracture patients）， group B （Lisfranc injury patients）， group C （flat foot patients）， group D （bunion valva patients）；Each group was randomly divided into control group and observation groups according to the random number table method. The patients in control group were diagnosed and treated according to traditional imaging evaluation； In the observation group， lower extremity biomechanical assessment was added along with imaging evaluation to make diagnosis and treatment plan，and the differences of diagnosis results between the two groups were recorded. Follow-up visits at 3 months and 12 months after the end of treatment were conducted to evaluate the improvement using the AOFAS（American Orthopaedic Foot and Ankle Society） median foot score and VAS （Visual Analogue Scales） scores. The therapeutic effects of the control group and the observation group were statistically analyzed.

Results

Among 81 patients suspected of ankle fracture in each group of GroupA，the diagnostic accuracy of the observation group was 92.59%，higher than that of the control group（77.78%）.The rates of misdiagnosis and missed diagnosis were 28.57%and 5.41%，lower than those of the control group （46.15% and 17.65%）， the difference was statistically significant （P＜0.05）.Among 35 patients with suspected Lisfranc injury in each group of Group B，the diagnostic accuracy of the observation group was 94.29%，higher than that of the control group（62.86%）.The rates of misdiagnosis and missed diagnosis were 12.50% and 3.70%， lower than those of the control group （70.00% and 24.00%），the difference was statistically significant（P＜0.05）.Among 42 patients suspected of flatfoot in each group of GroupC，the diagnostic accuracy of the observation group was 95.24%，higher than that of the control group（71.43%）.The rates of misdiagnosis and missed diagnosis were 10.00% and 3.13%， lower than those of the control group （50.00% and 20.00%）， the difference was statistically significant （P＜0.05）. Similarly，Among 22 suspected bunion valgus patients in each group of GroupD， the diagnostic accuracy of observation group was 90.91%，higher than that of control group（59.09%）.The rates of misdiagnosis and missed diagnosis were 0.00%and 11.11%，lower than those of the control group（80.00%and 29.41%），the difference was statistically significant （P＜0.05）. Correlation analysis showed that AOFAS and VAS scores were the most correlated with the peak pressure of medial foot （r=0.787，-0.740， P=0.012， 0.033） among ankle fracture patients. The correlation between AOFAS score and average walking speed was the strongest （r=0.711， P=0.015）， and the correlation between VAS score and peak pressure of medial foot was the strongest（r=-0.707，P=0.013）in Lisfranc injury patients.The correlation between AOFAS score and self-selected step speed was the strongest（r=0.597，P=0.035），the correlation between VAS score and the peak pressure of the first metatarsal bone was the strongest（r=-0.550，P=0.041）in patients with flat feet.In bunion valgus patients，the correlation between AOFAS score and the peak pressure of the first metatarsal bone was the strongest（r=0.641，P=0.027），and the correlation between VAS score and the peak pressure of the medial foot was the strongest （r=-0.623， P=0.042）.

Conclusions

The addition of biomechanical evaluation on the basis of traditional X-ray diagnosis could significantly improve the accuracy of some diagnosis of foot and ankle diseases.A part of the mechanical evaluation indexes had strong correlation with the clinical scores of patients，and might have guiding significance for the treatment of foot and ankle diseases，as well as postoperative rehabilitation.

Key words: Ankle fracture, Lisfranc injury, Flat foot, Hallux valgus, Biomechanical evaluation