Outcomes of Total Knee Arthroplasty in Relation to Preoperative Patient-Reported and Radiographic Measures

Abstract

Introduction: Total knee arthroplasty (TKA) is the preferred surgical treatment for end-stage osteoarthritis. However, substantial numbers of patients still experience poor outcomes. Consequently, it is important to identify which patient characteristics are predictive of outcomes in order to guide clinical decisions. Our hypothesis is that preoperative patient-reported outcome measures and radiographic measures may help to predict TKA outcomes. Methods: Using cohort data from the Osteoarthritis Initiative, we studied 172 patients who underwent TKA. For each patient, we compiled pre-and postoperative Western Ontario and McMaster University Arthritis Index (WOMAC) scores. Radiographs were measured for knee joint angles, femorotibial angles, anatomical lateral distal femoral angles, and anatomical medial proximal tibial angles; Kellgren and Lawrence (KL) grades were assigned to each compartment of the knee. All studied measurements were compared to WOMAC outcomes. Results: Preoperative WOMAC disability, pain, and total scores were positively associated with postoperative WOMAC total scores (P ¼ .010, P ¼ .010, and P ¼ .009, respectively) and were associated with improvement in WOMAC total scores (P < .001, P < .001, and P < .001, respectively). For radiographic measurements, preoperative joint angles were positively associated with improvements in postoperative WOMAC total scores (P ¼ .044). Combined KL grades (medial and lateral compartments) were negatively correlated with postoperative WOMAC disability and pain scores (P ¼ .045 and P ¼ .044) and were positively correlated with improvements in WOMAC total scores (P ¼ .001). Conclusions: All preoperative WOMAC scores demonstrated positive associations with postoperative WOMAC scores, while among the preoperative radiographic measurements only combined KL grades and joint angles showed any correlation with postoperative WOMAC scores. Higher preoperative KL grades and joint angles were associated with better (lower) postoperative WOMAC scores, demonstrating an inverse correlation.

Can Preoperative Patient-reported Outcome Measures Be Used to Predict Meaningful Improvement in Function After TKA?

“…This suggests that patients with baseline KOOS scores greater than 58 are progressively less likely to experience a clinically meaningful improvement after surgery. This trend of diminishing returns with higher baseline functional capacity has been previously described [24,26]. These findings are consistent with prior evidence suggesting that preoperative pain and functional status are predictive of functional ability after TKA [15,27,40].…”

“…Additionally, the multivariate analysis demonstrated that baseline SF12v2 MCS scores paralleled functional threshold values. These findings are consistent with prior evidence, which demonstrates that poorer baseline mental and emotional health is associated with smaller improvement in function after TKA [4,5,13,16,17,19,24,26,27,40,43,44]. By comparison, patient comorbidities and age have little effect on PROM scores after TKA [13,32].…”

“…More specifically, although patients with higher levels of preoperative pain and disability demonstrate the greatest improvements in PROM scores, they do not achieve absolute postoperative scores comparable to patients with less preoperative pain and better baseline function [13,24]. A substantial body of evidence has also demonstrated that mental and emotional health influence postoperative PROMs after TKA [4,5,13,16,17,19,24,26,27,40,43,44]. Worse preoperative mental and emotional health is associated with smaller improvements in physical function scores after TKA [4,5,16,17,22,27,40].…”

Functional gain following knee replacement in patients aged 75 and older: a prospective follow-up study

“…Our study supports the previous findings in this regard [33]. The effect of K-L score on the improvement in functional ability has been noted previously [34], and while we did not find an inverse correlation on the postoperative functional ability, such a correlation could not be ruled out. The improvement in ADL scores was clearly superior in patients with preoperative varus deformity as compared to those with a valgus deformity.…”

Younger patients have less severe radiographic disease and lower reported outcome scores than older patients undergoing total knee arthroplasty

“…Polkowski et al have noted that as many as 50% of patients who present for assessment of a painful TKA with acceptable postoperative radiographs had only mild or moderate preoperative radiographic disease at the time of their primary TKA procedure [19]. While several published studies have suggested a relationship between preoperative malalignment and obesity on the progression of knee osteoarthritis and postoperative TKA clinical outcome scores, these studies have not specifically reported on the radiographic disease severity of patients related to patient age at the time of TKA surgery [4][5][6]8,11,22]. We performed this study to assess the radiographic disease severity of younger patients (≤55 years old) at the time of TKA surgery and the relationship between radiographic disease severity, patient demographic features, and preoperative patient reported outcome measures.…”