Patient reported outcome measures (PROMs) as primary and secondary outcomes in total hip and knee arthroplasty randomized controlled trials: a systematic review.

BACKGROUND: Significant heterogeneity exists regarding patient reported outcome measures (PROMs) used in total hip (THA) and knee (TKA) arthroplasty randomized controlled trials (RCTs). This study investigates the PROMs used as primary and secondary outcomes in contemporary arthroplasty RCTs.

METHODS: A literature search identified THA and TKA RCTs that were published in top ten impact factor orthopaedic journals from 2017 to 2021. Screening identified 241 trials: 76 THA, 157 TKA, and eight combined. Data were extracted to identify PROMs utilized as either primary or secondary outcomes and the time period of measurement.

RESULTS: Visual Analog Scale (VAS) Pain was the most reported primary PROM in THA (9.2%) and TKA (22.9%) trials. This was followed by Numeric Rating Scale (NRS) Pain (7.9%) and the Harris Hip score (6.6%) in THA trials and NRS Pain (4.5%) and the Knee Society score (4.5%) in TKA trials. Many THA (37.0%) and TKA (52.1%) trials did not clearly specify primary outcome time points. Only pain scales were reported at time points less than one week, while various joint-specific functional outcomes were reported at later time points. As secondary outcomes, the Harris Hip score (28.9%) was most common in THA trials and the Knee Society score (26.1%) was most common in TKA trials. Indeterminate primary or secondary outcomes were reported in 18.2% of studies.

CONCLUSIONS: Contemporary THA and TKA trials exhibit heterogeneity of PROMs as study outcomes after the first postoperative week. Our findings highlight the need for consensus in PROM reporting and better methodological reporting to improve the interpretability of RCT outcomes.

PROSPERO REGISTRATION NUMBER: CRD42022337255.