MRI to Predict Joint Laxity in ACL Reconstruction Patients

Abstract and Introduction

Abstract

Background: The present study was performed to determine whether MRI findings can predict the degree of knee joint laxity in patients undergoing ACL reconstruction and whether the accuracy of the prediction is affected by the MRI acquisition time.

Methods: We assessed prospectively collected data of 154 knees with ACL tears. The presence or absence of four primary findings of ACL tears, i.e., nonvisualization, discontinuity, abnormal signal intensity, and abnormal shape of the ACL, and five secondary findings, i.e., anterior translation of the tibia relative to the femur (≥7 mm), posterior cruciate ligament angle (<105°), bone contusion, Segond fracture, and the deep sulcus sign, were determined. Knee joint laxity was assessed using the Lachman and pivot shift tests. The associations between MRI findings and clinically assessed knee joint laxity were analyzed and compared between subgroups (≤3 months from injury to MRI, 89 knees; >3 months, 65 knees).

Results: Nonvisualization was related to the results of the Lachman test [Odds ratio (OR), 2.6; 95% confidence interval (CI), 1.2–5.5]. Anterior translation of the tibia relative to the femur was related to the results of the pivot shift test (OR, 3.8; 95% CI, 1.6–9.4). In subgroup comparisons of the early and late MRI groups, anterior translation of the tibia relative to the femur was related to the results of the pivot shift test in the early MRI group (OR, 4.5; 95% CI, 1.4–14.4). In contrast, no MRI findings had statistically significant relationships with physical findings in the late MRI group.

Conclusions: Our study indicates that MRI findings may have some usefulness for predicting the grade of knee laxity in patients with symptomatic ACL injury, but its value is limited, especially in patients with a longer time interval between injury and the performance of MRI.

Table 1. Comparison of the demographic characteristics between the early and late MRI groups
Parameter	Early MRI group (n = 89)	Late MRI group (n = 65)	P-value
Number of male patients*	73 (82)	61 (94)	0.031
Age (years)^†	31.4 ± 9.8	33.8 ± 9.1	0.124
Time from MRI to physical examination (days)^†	34.2 ± 21.8	35.3 ± 24.0	0.939
Time from injury to MRI (days)	18 (5–37)	733 (201–1915)	NA

Table 2. Comparisons of four primary and five secondary findings on magnetic resonance imaging between low-grade and high-grade instability on the Lachman and pivot shift tests ( n = 154)
Parameter	Lachman test	OR (95% CI)	P-value	Pivot shift test	OR (95% CI)	P-value
Low (n = 86)	High (n = 68)	Low (n = 25)	High (n = 129)
Primary findings
Nonvisualization	15	24	2.6 (1.2–5.5)	0.011	3	36	2.8 (0.8–10.1)	0.094
Discontinuity	57	36	1.1 (0.4–2.7)	0.914	18	75	0.8 (0.3–2.7)	0.764
Abnormal signal	46	31	1.3 (0.6–2.8)	0.579	16	61	0.7 (0.2–1.9)	0.448
Abnormal shape	43	30	1.4 (0.6–3.0)	0.451	15	58	0.7 (0.3–2.0)	0.534
Secondary findings
Deep sulcus sign	31	19	0.7 (0.4–1.4)	0.286	10	40	0.7 (0.3–1.6)	0.380
Segond fracture	3	1	0.4 (0.04–4.1)	0.630	1	3	0.6 (0.1–5.7)	0.511
PCL angle (<105°)	31	32	1.6 (0.8–3.0)	0.168	9	54	1.3 (0.5–3.1)	0.585
Anterior translation (≥7 mm)	51	46	1.4 (0.7–2.8)	0.287	9	88	3.8 (1.6–9.4)	0.002
Bone contusion
Absent or medial compartment	34	29	1.1 (0.6–2.2)	0.696	9	54	1.3 (0.5–3.1)	0.585
Lateral compartment	26	22	1.1 (0.6–2.2)	0.778	7	41	1.2 (0.5–3.1)	0.709
Both compartments	26	17	0.8 (0.4–1.6)	0.472	9	34	1.1 (0.6–2.2)	0.325

Table 2. Comparisons of four primary and five secondary findings on magnetic resonance imaging between low-grade and high-grade instability on the Lachman and pivot shift tests ( n = 154)

Parameter

Lachman test

OR (95% CI)

P-value

Pivot shift test

OR (95% CI)

P-value

Low (n = 86)

High (n = 68)

Low (n = 25)

High (n = 129)

Primary findings

Nonvisualization

2.6 (1.2–5.5)

0.011

2.8 (0.8–10.1)

0.094

Discontinuity

1.1 (0.4–2.7)

0.914

0.8 (0.3–2.7)

0.764

Abnormal signal

1.3 (0.6–2.8)

0.579

0.7 (0.2–1.9)

0.448

Abnormal shape

1.4 (0.6–3.0)

0.451

0.7 (0.3–2.0)

0.534

Secondary findings

Deep sulcus sign

0.7 (0.4–1.4)

0.286

0.7 (0.3–1.6)

0.380

Segond fracture

0.4 (0.04–4.1)

0.630

0.6 (0.1–5.7)

0.511

PCL angle (<105°)

1.6 (0.8–3.0)

0.168

1.3 (0.5–3.1)

0.585

Anterior translation (≥7 mm)

1.4 (0.7–2.8)

0.287

3.8 (1.6–9.4)

0.002

Bone contusion

Absent or medial compartment

1.1 (0.6–2.2)

0.696

1.3 (0.5–3.1)

0.585

Lateral compartment

1.1 (0.6–2.2)

0.778

1.2 (0.5–3.1)

0.709

Both compartments

0.8 (0.4–1.6)

0.472

1.1 (0.6–2.2)

0.325

Table 3. Comparisons of the four primary and five secondary findings on MRI and low- and high-grade instability on the Lachman and pivot shift tests
Parameter	Early MRI group (n=89)	Late MRI group (n=65)
Lachman test	OR (95% CI)	Pivot shift test	OR (95% CI)	Lachman test	OR (95% CI)	Pivot shift test	OR (95% CI)
Low (n=51)	High (n=38)	Low (n=16)	High (n=73)	Low (n=35)	High (n=30)	Low (n=9)	High (n=56)
Primary findings
Nonvisualization	4	8	3.1 (0.9–11.3) ^#	1	11	2.7 (0.3–22.5)	11	16	2.5 (0.9–6.9) ^†	2	25	2.8 (0.5–14.8)
Discontinuity	36	25	1.5 (0.5–5.0)	14	47	0.2 (0.03–1.9)	21	11	0.5 (0.1–2.5)	4	28	4.2 (0.7–24.8)
Abnormal signal	36	24	1.2 (0.4–3.8)	13	47	0.5 (0.1–2.4)	10	7	1.3 (0.4–4.8)	3	14	1.0 (0.2–5.1)
Abnormal shape	33	24	1.7 (0.6–5.1)	12	45	0.7 (0.2–2.6)	10	6	1.0 (0.3–3.7)	3	13	0.9 (0.2–4.5)
Secondary findings
Deep sulcus sign	22	15	0.9 (0.4–2.0)	8	29	0.7 (0.2–2.0)	9	4	0.4 (0.1–1.6)	2	11	0.9 (0.2–4.7)
Segond fracture	2	1	0.7 (0.1–7.6)	1	2	0.4 (0.04–5.0)	1	0	1.0 (0.9–1.0)	0	1	1.0 (1.0–1.1)
PCL angle (<105°)	12	10	1.2 (0.4–3.1)	2	20	2.6 (0.6–12.7)	19	22	2.3 (0.8–6.6)	7	34	0.4 (0.1–2.3)
Anterior translation (≥7 mm)	31	23	1.0 (0.4–2.3)	5	49	4.5 (1.4–14.4) ^*	20	23	2.5 (0.8–7.3) ^‡	4	39	2.9 (0.7–12.0)
Bone contusion
Absent or medial compartment	11	4	0.4 (0.1–1.5)	2	13	1.5 (0.3–7.5)	23	25	2.6 (0.8–8.6)	7	41	0.8 (0.2–4.2)
Lateral compartment	18	17	1.5 (0.6–3.5)	6	29	1.2 (0.4–3.4)	8	5	0.7 (0.2–2.3)	1	12	2.2 (0.3–19.2)
Both compartments	22	17	1.1 (0.5–2.5)	8	31	0.7 (0.3–2.2)	4	0	0.9 (0.8–1.0)	1	3	0.5 (0.04–4.9)

Table 3. Comparisons of the four primary and five secondary findings on MRI and low- and high-grade instability on the Lachman and pivot shift tests

Parameter

Early MRI group (n=89)

Late MRI group (n=65)

Lachman test

OR (95% CI)

Pivot shift test

OR (95% CI)

Lachman test

OR (95% CI)

Pivot shift test

OR (95% CI)

Low (n=51)

High (n=38)

Low (n=16)

High (n=73)

Low (n=35)

High (n=30)

Low (n=9)

High (n=56)

Primary findings

Nonvisualization

3.1 (0.9–11.3) ^#

2.7 (0.3–22.5)

2.5 (0.9–6.9) ^†

2.8 (0.5–14.8)

Discontinuity

1.5 (0.5–5.0)

0.2 (0.03–1.9)

0.5 (0.1–2.5)

4.2 (0.7–24.8)

Abnormal signal

1.2 (0.4–3.8)

0.5 (0.1–2.4)

1.3 (0.4–4.8)

1.0 (0.2–5.1)

Abnormal shape

1.7 (0.6–5.1)

0.7 (0.2–2.6)

1.0 (0.3–3.7)

0.9 (0.2–4.5)

Secondary findings

Deep sulcus sign

0.9 (0.4–2.0)

0.7 (0.2–2.0)

0.4 (0.1–1.6)

0.9 (0.2–4.7)

Segond fracture

0.7 (0.1–7.6)

0.4 (0.04–5.0)

1.0 (0.9–1.0)

1.0 (1.0–1.1)

PCL angle (<105°)

1.2 (0.4–3.1)

2.6 (0.6–12.7)

2.3 (0.8–6.6)

0.4 (0.1–2.3)

Anterior translation (≥7 mm)

1.0 (0.4–2.3)

4.5 (1.4–14.4) ^*

2.5 (0.8–7.3) ^‡

2.9 (0.7–12.0)

Bone contusion

Absent or medial compartment

0.4 (0.1–1.5)

1.5 (0.3–7.5)

2.6 (0.8–8.6)

0.8 (0.2–4.2)

Lateral compartment

1.5 (0.6–3.5)

1.2 (0.4–3.4)

0.7 (0.2–2.3)

2.2 (0.3–19.2)

Both compartments

1.1 (0.5–2.5)

0.7 (0.3–2.2)

0.9 (0.8–1.0)

0.5 (0.04–4.9)

Can Magnetic Resonance Imaging Findings Predict the Degree of Knee Joint Laxity in Patients Undergoing Anterior Cruciate Ligament Reconstruction?

Abstract and Introduction

Abstract

Tables

Tables

Tables

References

Authors and Disclosures

Authors and Disclosures

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