Risk factors for progression to total knee arthroplasty within two years of presentation for knee osteoarthritis

Prospective validity of a clinical prediction rule for response to non-surgical multidisciplinary management of knee osteoarthritis in tertiary care: a multisite prospective longitudinal study

OBJECTIVES

We tested a previously developed clinical prediction tool-a nomogram consisting of four patient measures (lower patient-expected benefit, lower patient-reported knee function, greater knee varus angle and severe medial knee radiological degeneration) that were related to poor response to non-surgical management of knee osteoarthritis. This study sought to prospectively evaluate the predictive validity of this nomogram to identify patients most likely to respond poorly to non-surgical management of knee osteoarthritis.

DESIGN

Multisite prospective longitudinal study.

SETTING

Advanced practice physiotherapist-led multidisciplinary service across six tertiary hospitals.

PARTICIPANTS

Participants with knee osteoarthritis deemed appropriate for trial of non-surgical management following an initial assessment from an advanced practice physiotherapist were eligible for inclusion.

INTERVENTIONS

Baseline clinical nomogram scores were collected before a trial of individualised non-surgical management commenced.

PRIMARY OUTCOME MEASURE

Clinical outcome (Global Rating of Change) was collected 6 months following commencement of non-surgical management and dichotomised to responder (a little better to a very great deal better) or poor responder (almost the same to a very great deal worse). Clinical nomogram accuracy was evaluated from receiver operating characteristics curve analysis and area under the curve, and sensitivity/specificity and positive/negative likelihood ratios were calculated.

RESULTS

A total of 242 participants enrolled. Follow-up scores were obtained from 210 participants (87% response rate). The clinical nomogram demonstrated an area under the curve of 0.70 (p<0.001), with greatest combined sensitivity 0.65 and specificity 0.64. The positive likelihood ratio was 1.81 (95% CI 1.32 to 2.36) and negative likelihood ratio 0.55 (95% CI 0.41 to 0.75).

CONCLUSIONS

The knee osteoarthritis clinical nomogram prediction tool may have capacity to identify patients at risk of poor response to non-surgical management. Further work is required to determine the implications for service delivery, feasibility and impact of implementing the nomogram in clinical practice.

Early Clinical Outcomes of "Lemon-Dropped" Complex Primary Total Joint Arthroplasty Patients to a Tertiary Care Center

BACKGROUND

In the era of value-based care, pressures lead to cherry-picking healthier patients and lemon-dropping riskier patients to higher levels-of-care. This study examined whether "lemon-dropped" primary total joint arthroplasty (pTJA) patients require increased health care resources and experience worse outcomes.

METHODS

This was a retrospective cohort study of all pTJAs at one tertiary care center in 2022, excluding bilaterals, acute fractures, oncologic cases, and conversion hips. Patients were classified via referral pattern as simple or complex (referred for medical or surgical complexity). Primary outcomes were implant costs and any emergency department visit, readmission, reoperation, or complication within 90 days. Secondary outcomes were distance traveled to the hospital, anesthesia type, estimated blood loss, case duration, time in the recovery unit, length of stay, and discharge disposition. Outcomes were assessed via electronic medical record review and analyzed via Fisher's exact and unpaired Welch's t-tests.

RESULTS

In total 641 pTJAs (322 hips, 319 knees) met inclusion criteria; 10.3% were complex referrals. Complex patients were younger (59 versus 66 years, P < .05) and more often non-White (41 versus 31%, P < .001), non-English speaking (11 versus 7%, P < .001), and had nonprimary osteoarthritis as a surgical indication (59 versus 12%, P < .001), but had similar Charlson Comorbidity Index and American Society of Anesthesiologists scores. Complex patients had increased odds of 90-day emergency department visits (OR [odds ratio] = 2.11, P = .04), 90-day complications (OR = 2.63, P < .001), and non-home discharge (OR = 2.60, P = .006); higher mean relative implant costs (1.31x, P < .001); longer time in the operating room (181 versus 158 minutes P < .001), time in surgery (125 versus 105 minutes, P < .001), and length of stay (3.2 versus 1.7 days, P = .005).

CONCLUSIONS

"Lemon-dropped" pTJAs had worse early clinical outcomes and higher health care utilization, despite a control group with patients ill enough to utilize a tertiary care center as their medical home. Reimbursement models and evaluation metrics must account for these differences.

The Prognostic Potential of End-Stage Knee Osteoarthritis and Its Components to Predict Knee Replacement: Data From the Osteoarthritis Initiative

OBJECTIVE

We aimed to determine how 2 definitions of end-stage knee osteoarthritis (esKOA) and each component (knee symptoms, persistent knee pain, radiographic severity, and presence of limited mobility or instability) related to future knee replacement (KR).

METHODS

We performed knee-based analyses of Osteoarthritis Initiative data from baseline to the first 4 annual follow-up visits, and data on KR from baseline until the fifth yearly contact. We calculated a base model using common risk factors for KR in logistic regression models with generalized estimating equations. We assessed model performance with area under the receiver-operating characteristic curve (AUC) and Hosmer-Lemeshow test. We then added esKOA or each component from the visit (< 12 months) before a KR and change in the year before a KR. We calculated the net reclassification improvement (NRI) index and the integrated discrimination improvement (IDI) index.

RESULTS

Our sample was mostly female (58%), ≥ 65 years old, White (82%), and without radiographic knee osteoarthritis (50%). At the visit before a KR, Kellgren-Lawrence (KL) grades (ordinal scale; AUC 0.88, NRI 1.12, IDI 0.11), the alternate definition of esKOA (AUC 0.84, NRI 1.16, IDI 0.12), and a model with every component of esKOA (AUC 0.91, NRI 1.30, IDI 0.17) had the best performances. During the year before a KR, change in esKOA status (alternate definition) had the best performance (AUC 0.86, NRI 1.24, IDI 0.12).

CONCLUSION

Radiographic severity may be a screening tool to find a knee that will likely receive a KR. However, esKOA may be an ideal outcome in clinical trials because a change in esKOA state predicts future KR.

The Usefulness of Synovial Fluid Proteome Analysis in Orthopaedics: Focus on Osteoarthritis and Periprosthetic Joint Infections

Synovial fluid (SF) is a viscous and mucinous substance produced by the synovium, a specialized connective tissue that lines diarthrodial joints. SF represents a source of disease-related proteins that could be used as potential biomarkers in several articular diseases. Based on these findings the study of SF has been gaining increasing importance, in recent years. This review aims to summarize the usefulness of synovial fluid in orthopaedics research and clinical practice, mainly focusing on osteoarthritis (OA) and periprosthetic joint infections (PJIs). Proteomics of the SF has shown the up-regulation of several components of the classic complement pathway in OA samples, including C1, C2, C3, C4A, C4B, C5, and C4 C4BPA, thus depicting that complement is involved in the pathogenesis of OA. Moreover, proteomics has demonstrated that some pro-inflammatory cytokines, namely IL-6, IL-8, and IL-18, have a role in OA. Several SF proteins have been studied to improve the diagnosis of PJIs, including alpha-defensin (Alpha-D), leukocyte esterase (LE), c-reactive protein (CRP), interleukin-6 (IL-6), calprotectin and presepsin. The limits and potentials of these SF biomarkers will be discussed.