High-Grade Posterolateral Tibial Plateau Impaction Fractures in the Setting of a Primary Anterior Cruciate Ligament Tear Are Correlated With an Increased Preoperative Pivot Shift and Inferior Postoperative Outcomes After Anterior Cruciate Ligament Reconstruction

Abstract

Background: Impaction fractures of the posterolateral tibial plateau have been previously described to occur in association with anterior cruciate ligament (ACL) tears; however, the effect of these injuries on patient-reported outcomes (PROs) after ACL reconstruction (ACLR) is not well known. Purpose: (1) To assess the effect of posterolateral tibial plateau impaction fractures on preoperative clinical knee stability assessed by the Lachman and pivot-shift examinations and (2) to assess the effect of impaction fractures on PROs after ACLR. Study Design: Cohort study; Level of evidence, 3. Methods: Patients undergoing ACLR for primary ACL tears with available magnetic resonance imaging (MRI) scans were included in this study. MRI scans were reviewed for the presence of posterolateral tibial plateau impaction fractures, which were classified according to the morphological variant. Associations with clinical laxity determined by an examination under anesthesia were assessed using binary logistic regression. Also, 2-year postoperative PROs (12-Item Short Form Health Survey [SF-12] Mental Component Scale and Physical Component Scale [PCS], Lysholm, Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], and Tegner scores) were modeled using multiple ordinal logistic regression to assess the effect of posterolateral tibial plateau impaction fracture classification while adjusting for other covariates. Pearson correlation coefficients (PCCs) were used to assess for correlations between postoperative PROs and the amount of tibial plateau bone loss present. Results: Displaced posterolateral tibial plateau impaction fractures were present in 407 (49.3%) of 825 total knees included in this study. Knees with type IIIB impaction fractures had an increased likelihood of having a high-grade pivot shift (odds ratio, 2.3; P = .047), with no other impaction fracture types showing a significant association. There were no significant associations between posterolateral tibial plateau impaction fracture type and a higher Lachman grade. Of the 599 eligible knees with 2-year follow-up, postoperative information was obtained for 419 (70.0%). Patients improved in all PROs at a mean of 3.0 years after ACLR ( P < .001). Multiple ordinal logistic regression demonstrated a posterolateral tibial plateau impaction fracture as an independent predictor of the postoperative Lysholm score, with higher grade impaction fractures showing decreased Lysholm scores. Pearson correlation testing demonstrated weak but statistically significant correlations between sagittal bone loss of posterolateral tibial plateau impaction fractures and SF-12 PCS (PCC = –0.156; P = .023), WOMAC total (PCC = 0.159; P = .02), Lysholm (PCC = –0.203; P = .003), and Tegner scores (PCC = –0.151; P = .032). Conclusion: When classified into distinct morphological subtypes, high-grade posterolateral tibial plateau impaction fractures were independently associated with decreased postoperative outcomes after ACLR when controlling for other demographic or clinical variables. Patients with large depression-type posterolateral tibial plateau impaction fractures (type IIIB) had an increased likelihood of having high-grade pivot-shift laxity on clinical examination under anesthesia.

Machine learning algorithm to predict anterior cruciate ligament revision demonstrates external validity

“…As noted in the original paper, this may be related to data quality since several risk factors for failure of ACL reconstruction are not captured in the NKLR [ 19 ]. Examples of these factors include radiographic variables such as tibial slope and coronal alignment [ 2 – 4 , 10 , 15 , 20 , 31 ], physical examination and rehabilitation details [ 11 , 14 , 18 , 22 ], and surgical technique factors such as tunnel position [ 16 ] and graft size [ 1 , 7 , 17 ]. The addition of these variables into the national knee ligament registers may improve future machine learning prediction endeavours.…”

Predicting subjective failure of ACL reconstruction: a machine learning analysis of the Norwegian Knee Ligament Register and patient reported outcomes

“…Although this included several known risk factors for ACL reconstruction failure, there are also many other factors that may be associated with poor outcome that are not recorded in the NKLR. Examples of these include radiographic variables such as tibial slope and coronal alignment [24][25][26][27][28], physical examination and rehabilitation details [29,30], and surgical technique factors such as tunnel position [31] and graft size [32,33]. Further, while meniscus and chondral injuries were recorded, the surgical treatments employed at the time of surgery were not included as variables and may represent a source of exclusion bias.…”

Editorial Commentary: Outcomes After Anterior Cruciate Ligament Reconstruction Are Defined by Individual Anatomy, Including Both Soft Tissue and Bone Morphology: It’s All Important

“…12 Furthermore, some morphologic differences that reflect pathologic states, such as the lateral notch sign and posterolateral plateau fracture, have been shown to be associated with greater grade instability. 13,14 In summary, the role of bony morphology has been under-appreciated until recently, and the authors' investigation of the influence of the sagittal inclination angle is a step in the right direction. It is, however, a 2dimensional glimpse of a static parameter, whereas the knee is a 3-dimensional structure involved in complex dynamic activities such as cutting and pivoting.…”