The influence of distribution, severity and volume of posttraumatic bone bruise on functional outcome after ACL reconstruction for isolated ACL injuries

Abstract

Introduction: Posttraumatic MRI of ACL tears show a high prevalence of bone bruise (BB) without macroscopic proof of chondral damage. Controversial results are described concerning the association between BB and outcome after ACL tear. Aim of this study is to evaluate the influence of distribution, severity and volume of BB in isolated ACL injuries on function, quality of life and muscle strength following ACL reconstruction (ACLR).

Materials and methods: MRI of n = 122 patients treated by ACLR without concomitant pathologies were evaluated. BB was differentiated by four localizations: medial/lateral femoral condyle (MFC/LFC) and medial/lateral tibial plateau (MTP/LTP). Severity was graded according to Costa-Paz. BB volumes of n = 46 patients were quantified (software-assisted volumetry). Outcome was measured by Lysholm Score (LS), Tegner Activity Scale (TAS), IKDC, isokinetics and SF-36. Measurements were conducted preoperatively (t0), 6 weeks (t1), 26 weeks (t2) and 52 weeks (t3) after ACLR.

Results: The prevalence of BB was 91.8%. LTP was present in 91.8%, LFC 64.8%, MTP 49.2% and MFC 28.7%. 18.9% were classified Costa-Paz I, 58.2% II and 14.8% III. Total BB volume was 21.84 ± 15.27 cm³, the highest value for LTP (14.31 ± 9.93 cm³). LS/TAS/IKDC/SF-36/isokinetics improved significantly between t0-t3 (p < 0.001). Distribution, severity and volume had no influence on LS/TAS/IKDC/SF-36/isokinetics (n.s.).

Conclusions: No impact of BB after ACLR on function, quality of life and objective muscle strength was shown, unaffected by concomitant pathologies. Previous data regarding prevalence and distribution is confirmed. These results help surgeons counselling patients regarding the interpretation of extensive BB findings. Long-time follow-up studies are mandatory to evaluate an impact of BB on knee function due to secondary arthritis.

Keywords: ACL injury; Bone bruise; Bone marrow edema; MRI; Outcome.

Fig. 1

Flow of patients through the study. CONSORT diagram presenting the enrolment of the final study population according to [22]

Fig. 2

MRI examples of study patients presenting with posttraumatic BB accompanying ACL injury. a–c Costa-Paz type 1 of the lateral tibial plateau and lateral femoral condyle; axial, coronal and sagittal. d–f BB type Costa-Paz type 2 of the lateral tibial plateau and lateral femoral condyle; axial, coronal and sagittal. g–i Costa-Paz type 3 of the lateral femoral condyle with “lateral femoral notch sign”; sagittal and coronal. (a–g, i = PD tse, h = T1)

Fig. 3

IKDC improvement over time. Mean subjective IKDC Scores and their improvement for all patients presenting with no BB and BB severities Costa-Paz 1–3 preoperatively (t0), 6 weeks (t1), 26 weeks (t2) and 52 weeks (t3) after the operation

Fig. 4

SF-36 improvement over time. Mean SF-36 Physical Health Summary Scales and their improvement for all patients presenting with no BB and BB severities Costa-Paz 1–3 preoperatively (t0), 6 weeks (t1), 26 weeks (t2) and 52 weeks (t3) after the operation

Fig. 5

Isokinetic extension strength improvement over time. Reduction of isokinetic strength deficit for knee extension for all patients presenting with no BB and BB severities Costa-Paz 1–3 26 weeks (t2) and 52 weeks (t3) after the operation

Fig. 6

Isokinetic flexion strength improvement over time. Reduction of isokinetic strength deficit for knee flexion for all patients presenting with no BB and BB severities Costa-Paz 1–3 26 weeks (t2) and 52 weeks (t3) after the operation