(The) Contact area and pressures according to A 2mm displacement in isolated meidal malleolar fractires : a cadaver study

다국어 초록 (Multilingual Abstract)

Objective : Ankle fractures constitute 9% of all fractures, and 1of 5 ankle fractures are isolated medial malleolar fractures (IMMFs). Conservative treatment is recommended for IMMF with displacement ≤2 mm, but it remains controversial and medical evidence is lacking. This study was performed to evaluate the changes in contact area and pressure in the tibiotalar joint, with a 2mm displacement after IMMF.

Materials and Methods : Ten cadavers (six male and four female cadavers: mean age, 66 years)were used to establish a situation in which IMMF occurred during ankle injury. I performed IMMF corresponding to types C and D of the Herscovici classification, and it was displaced by 2 mm. The normal group was defined as a normal tibiotalar joint, the TF(transverse fracture) group as a 2 mm transverse displacement corresponding to the Herscovici classification type C, and the OF(oblique fracture) group as a 2 mm oblique displacement corresponding to the Herscovici classification type D.
A universal mechanical testing machine was used for axial loading. I used a low-grade pressure-sensitive(prescale) film to measure the contact area and pressureat the tiobiotalar joint. The talar contact surface was divided into nine zones and changes in average pressure and peak pressure were measured. For statistical analysis, the Wilcoxon signed-rank test was used to compare the normal group and TF groups, and the normal group and OF groups. The Mann-Whitney U test was used to compare the TF and OF groups.

Results : In normal group, the average contact area of the tibiotalar joint was 317mm2(256-347) and 308mm2(262-364), average pressure was 2.19N/mm2(1.94-2.27) and 2.15N/mm2(2.06-2.53), and peak pressure was 5.99N/mm2(4.45-6.72) and 5.74 N/mm2(4.63-6.95). In the TF and OF groups, the average contact area decreased by 9% and 12%, respectively, and the average pressure increased by 8% and 14%, respectively. There was no statistical difference in peak pressure between the normal, TF, and OF groups. When the talar contact surface was divided into nine zones, the peak pressure difference in the central-medial zone was 0.046 after oblique fracture.

Conclusion : In the case of transverse and oblique fractures, a 2mm displacement showed significant changes in contact area and contact pressure compared to the normal tibiotalar joint, but there were no significant changes pertaining to shape, between the two fractures. With a 2 mm displacement after oblique fracture, a significant increase in peak pressure was observed in the central-medial zone.

Clinical Relevance : The indications for surgery or conservative treatment of IMMF remain unclear. This study was performed to evaluate the changes in contact area and pressure in the tibiotalar joint with a 2 mm displacement after IMMF.

국문 초록 (Abstract)

연구목적: 족관절 골절은 전체 골절에서 약 9%를 차지하고, 내과 단독 골절은 족관절 골절의 약 5분의 1정도이다. 2mm이하의 내과 단독 골절은 보존적 치료가 권장되지만, 논란이 있으며, 의학적 근거는 부족한 실태이다. 본 연구의 목적은 2mm의 전위가 있는 내과 단독 골절에서 족관절 내 접촉 면적과 압력의 변화를 측정하는 것이다.

연구방법: 10구의 사체(남자 6구와 여자 4구, 평균 나이 66세)에 내과 단독 골절을 만들어 연구를 진행하였다. 정상 20족, 수평 골절 10족, 경사 골절 10족으로 관절내 접촉면적과 압력 변화를 측정하였다. 수평 골절군은 Herscovici 분류 C, 경사 골절군은 Herscovici 분류 D에 따라 2mm 전위를 만들고, 나사 고정 후 계측하였다.
족관절에 수직 부하 기계로 압력을 가하고, 족관절내에 접촉면과 압력변화를 특수 필름을 이용하여 측정하였다. 거골 접촉면은 아홉 구획으로 나뉘어 평균 압력과 최고 압력을 측정하였다. 정상과 수평 골절군, 정상과 경사 골절군의 결과 비교를 위하여 Wilcoxon signed-rank test를 사용하였고, 수평 골절군과 경사 골절군의 비교를 위해 Mann-Whitney U test를 사용하였다.

결과: 정상군에서 관절 내 접촉면적은 317mm2(256-347)와308mm2(262-364
)이었다. 평균 압력은 2.19N/mm2(1.94-2.27)와 2.15 N/mm2(2.06-2.53)이었으며, 최대 압력은 5.99N/mm2(4.45-6.72)와 5.74 N/mm2(4.63-6.95)로 측정되었다. 수평 골절군에서 접촉 면적은 9% 감소, 평균압력은 8% 증가하였으며, 경사 골절군에서 접촉면적은 12% 감소, 평균 압력은 14% 증가 하였다. 거골 면적을 아홉 구획으로 나눈 연구에서는 경사 골절군에서 최대압력 증가가 중앙-내측 구획에서 유의하게 측정되었다.

결론: 2mm 전위가 있는 수평 골절군과 경사 골절군에서 정상과 비교하여, 통계적으로 유의한 접촉면적의 감소와 평균 압력의 증가가 관찰되었다. 그러나 골절의 형태에 따른 변화에는 유의한 결과는 관찰되지 않았다. 거골 면적을 아홉 구획으로 나누었을 때, 경사 골절군에서 중앙-내측 구획에서 최대압력이 유의하게 증가되었다.

목차 (Table of Contents)

• Ⅰ. Introduction 1
• Ⅱ. Materials and Methods 2
• 1) Specimen preparation 2
• 2) Osteotomy & fixation with 2mm block 3
• 3) Mechinical setup 4
• 4) Pressure-sensitive film 5
• 5) Measurement of contact area and contact pressure 5
• 6) statistical analysis 7
• Ⅲ. Results 8
• 1) Comparison of contact area, average contact pressure, and peak pressure between the three groups 8
• 2) P-value of pressure change in nine zones 9
• Ⅳ. Discussion 10
• Ⅴ. Conclusion 14
• References 15
• Abstract 18

참고문헌 (Reference)

1. General principles of fracture treatment, Wood G., , 2003

2. The Online Materials Information Resource, MatWeb, 15 December 2017, , 2015

3. Fractures of the ankle ; analytic historic survey as the basis of new experimental , roentgenologic and clinical investigations, Lauge N., 56 ( 3 ) :259-317, , 1948