gms | German Medical Science

Objectives/Interrogation: In order to enhance indication quality, it is useful to know at which level of symptoms patients should be operated to achieve the potentially best postoperative result. The objective of this study was to define clinically relevant preoperative thresholds at which patients with thumb carpometacarpal osteoarthritis (CMC I OA) have the greatest chance to achieve a relevant symptom improvement and an acceptable symptom state after surgery.

Methods: In a prospective study, 151 patients with CMC I OA and indication for surgery were included. Patients were examined before and 3, 6 and 12 months after surgery. The Minimal Important Difference (MID), Minimal Important Change (MIC) and the Patient Acceptable Symptom State (PASS) for pain at rest, pain during activities and the brief Michigan Hand Outcomes Questionnaire (brief MHQ) were determined as well as the preoperative thresholds, which are predictive to achieve the MIC and PASS. Anchor-based approaches and receiver operating characteristics (ROC) curves were used.

Results and Conclusions: The MID for pain at rest, pain during activities and the brief MHQ was 1.4, 1.0 and 12 and the MIC was 1.9, 3.9 and 16, respectively. The PASS was 1.5, 2.5 and 70. Regarding the preoperative thresholds, patients with baseline pain at rest of 3.5 or greater were most likely to achieve the MIC, and patients with a preoperative score of 5.5 or less were most likely to achieve a PASS. For pain during activities, the thresholds were 6.5 for achieving the MIC and 7.5 for the PASS. For the brief MHQ, the threshold to achieve the MIC and PASS was equal with 47 points.

We suggest that patients should be operated if they have preoperative pain values between 3.5 and 5.5 at rest and between 6.5 and 7.5 during activities and a brief MHQ score of about 47. Within these reference values, patients have the greatest chance to achieve a subjectively relevant improvement and an acceptable symptom state.