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. 2021 May 13;55(5):1127-1134.
doi: 10.1007/s43465-021-00418-1. eCollection 2021 Oct.

Is Flexion Gap Rectangular in Native Indian Knees? Results of an MRI Study

Subodh Kumar Pathak  1 , Manish Sethi  2 , Abhijeet Ashok Salunke  3 , Praveen Thivari  1 , Rakesh Kumar Gautam  1 , Rashid Anjum  4 , Jasneet Chawla  1 , Aryan Sharma  1
Affiliations

Is Flexion Gap Rectangular in Native Indian Knees? Results of an MRI Study

Subodh Kumar Pathak et al. Indian J Orthop. .

Abstract

Background: The purpose of this study was to evaluate the flexion-gap of the native knees in the normal population and to assess any gender-specific variations in the flexion gap of the knees.

Methods: A total of 50 normal asymptomatic volunteers with normal knee radiographs were selected for MRI of the knee. The left knee was scanned in an open MRI using a T1-weighted sequence. Imaging was performed in neutral, passive varus and valgus stress at 90° of knee flexion by placing custom-made blocks on a special board consecutively below the distal part of the leg.

Results: The study population consisted of 26 males and 24 females with a mean age of 25.77 years. Under varus stress, the mean lateral flexion gap increased to 9.28 ± 1.53 mm and under valgus stress, the mean medial flexion gap increased to 2.75 ± 1.22 mm from neutral. The increase in the flexion gap on the lateral side was 5.28 ± 1.79 mm, which was significantly higher compared to that on the medial side. In gender-specific analysis, the mean lateral flexion gap was 10.21 mm in females and 8.46 mm in males under varus stress.

Conclusion: The findings of the study indicate that the lateral soft tissues are more lax compared to the medial soft tissue structures and this laxity is higher in females as compared to males. The study provides evidence of the existing physiological variations of these soft tissue structures resulting in a trapezoidal flexion gap in the native knees rather than the recommended rectangular gap.

Keywords: Knee; Laxity; MRI study; Total knee arthroplasty.

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Conflict of interest statement

Conflict of interestThe authors have no conflicts of interest to declare.

Figures

Fig. 1
Fig. 1
Custom-made blocks for applying the varus-valgus stress
Fig. 2
Fig. 2
a Position of the patient for imaging in neutral stress. b Position of the patient for imaging in varus stress. c Position of the patient for imaging in valgus stress
Fig. 3
Fig. 3
Different lines for measurements on the magnetic resonance imaging
Fig. 4
Fig. 4
a Flexion gap in neutral stress. b Flexion gap in varus stress. c Flexion gap in valgus stress
Fig. 5
Fig. 5
Box and whisker plot showing the difference in the flexion gap between the lateral and medial side with varus and valgus stress, respectively
Fig. 6
Fig. 6
Box and whisker plot showing the difference in the flexion gap between the genders
See this image and copyright information in PMC

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