Knee ligaments’ laxity assessment using GNRB® system after ACL reconstruction operation

Abstract

Purpose: to evaluate the BMI, age and graft diameter influence to recovery results using GNRB^®arthrometer system after anterior cruciate ligament reconstruction surgery.

Methods. Prospective study of 201 patients after ACL reconstruction in Hospital of LUHS. The operative age, sex, height and weight of patients and diameter of graft were recorded. Patients were divided into three groups according to the diameter of the middle part of graft: All patients were reviewed clinically by an independent examiner pre-surgery and 3, 6 and 12 months after surgery and laximetric measurements were taken using GNRB^® system. An ANOVA test was used to compare the diameter of the graft among those groups, BMI, age of patients with arthrometer results in 134N force. The Spearman’s rho was used to investigate the relationship between BMI and diameter of graft or age of patients. General Linear Model was used to compare the results of tests. The difference was statistically significant at p<0.05.

Results. We analyzed 201 patient’ data. There were 150 (74.6%) man 51 (25.4%) female. Patients were divided into three groups: group 1 (≤8mm) consisted of 42 patients (18 male and 24 female); group 2 (8.1–9mm) consisted of 81 patients (62 male and 19 female); group 3 (≥9.1mm) consisted of 78 patients (70 male and 8 female). Statistical significant difference was found in Group 1 and Group 3 by gender (χ²=31.958 p<0.001). Also statistical significant difference was found in all groups by graft diameter (F=241.03 p<0.001) and by BMI statistical significant difference was found in group 1 and group 3 (F=3.391 p=0.036). Significant correlation was found between BMI and graft diameter (R=0.215 p=0.002) and BMI and patients’ age (R=0.267 p<0.001). Statistical results of groups by graft diameter in four GNRB^® testing’s: a statistical difference was found among all testing’s (F=43.436 p<0.001 η²=0.63) and linear mean trend was observed (F=75.47 p<0.001). There was no statistical significant graft groups’ impact to testing result. Patient age’s (group 1 - <30 and group 2 - ≥30) influence to functional recovery (by GNRB^® measurements): a statistical difference was found among all testing’s (F=46.82 p<0.001 η²=0.63), linear mean trend was observed (F=79.35 p<0.001). There was no statistical significant age groups’ impact to testing result. BMI influence to functional recovery: a statistical difference was found among all testing’s (F=47.95 p<0.001 η²=0.64), linear mean trend was observed (F=84.72 p<0.001). There was no statistical significant BMI groups’ impact to testing result.

Conclusions. The GNRB^® system is reliable measurement system to perform evaluation of functional outcomes after anterior cruciate ligament reconstruction, statistical significant difference in test results and linear mean trend was observed. Statistical significant difference was between pre-operative test and later tests (3, 6, 12 months), but no significant difference observed testing pair vice in 3, 6, 12 months.  No statistical significant impact to functional outcomes was evaluated by graft diameter, BMI and age groups, but factors (graft diameter, BMI and patient’ age) have noticeable influence to the test results.