What are the primary outcome measures for tennis elbow?

Primary Outcome Measures for Tennis Elbow

The Patient-Rated Tennis Elbow Evaluation (PRTEE) questionnaire is the recommended primary outcome measure for tennis elbow (lateral epicondylitis) as it demonstrates excellent reliability, validity, and sensitivity to change in patients with this condition. 1

Recommended Primary Outcome Measure

• The PRTEE questionnaire specifically evaluates pain and functional limitations in patients with lateral epicondylitis, making it the most appropriate primary outcome measure 1, 2
• The PRTEE demonstrates excellent reliability and internal consistency (pain subscale: 0.94; specific activities subscale: 0.93; usual activities: 0.85) 1
• It has been validated across multiple languages and populations, confirming its cross-cultural applicability 3
• The PRTEE shows superior responsiveness to change compared to other outcome measures with a standardized response mean (SRM) of 2.1 1

Components of the PRTEE

• The PRTEE consists of two subscales: pain (0-50) and function (0-50), which combine for a total score (0-100) 2
• For the total PRTEE score, the minimal important change (MIC) is 9 points, while the smallest detectable change (SDC95%) is 17 points 2
• For the subscales, the MIC is 11 points for pain and 4 points for function, with SDC95% values of 8 and 12 points respectively 2

Recommended Secondary Outcome Measures

Pain Measures

• Pain on gripping (0-10 scale): Shows good construct validity and responsiveness with an MIC of 3.5 points and SDC95% of 4 points 2
• Visual Analog Scale (VAS): Demonstrates good correlation with the PRTEE and can be used to measure pain intensity 1

Functional Measures

• Pain-free grip strength: Shows good construct validity and responsiveness with an MIC of 6.5 kg and SDC95% of 6.4 kg 2
• Maximum grip strength: Has an MIC of 1 kg and SDC95% of 8.4 kg 2
• Disabilities of the Arm, Shoulder, and Hand (DASH) Questionnaire: Shows good correlation with the PRTEE and can provide broader assessment of upper extremity function 1, 3

Clinical Considerations for Outcome Assessment

• Radiographs are beneficial as initial imaging to rule out other pathologies such as intra-articular bodies, heterotopic ossification, or occult fractures 4, 5
• When evaluating treatment effectiveness, consider that tennis elbow is often self-limiting, with a 50% probability of recovery every three to four months regardless of intervention 6
• The interpretation of minimal important change can be challenging due to large measurement errors, so clinicians should consider both statistical and clinical significance when evaluating outcomes 2

Common Pitfalls in Outcome Measurement

• Relying solely on pain measures without assessing functional limitations may provide an incomplete picture of recovery 1
• Failing to establish baseline measurements before intervention makes it difficult to accurately assess treatment effectiveness 2
• Overreliance on imaging findings without correlation to clinical symptoms can lead to inappropriate treatment decisions 4
• Not considering the natural history of tennis elbow when interpreting outcomes may lead to overattribution of improvement to specific interventions 6

The PRTEE should be used as the primary outcome measure in tennis elbow assessment and research, supplemented by pain on gripping and grip strength measurements to provide a comprehensive evaluation of treatment effectiveness.