Does central sensitization correlate with two-year postoperative functional outcome scores following hip arthroscopy?

Background: Central sensitization (CS) involves amplified central nervous system (CNS) signaling and several biochemical changes which lead to pain hypersensitivity. Data on the effects of CS are limited in orthopaedics and has been associated with reported levels of postoperative pain after hip arthroscopy.

Methods: Patients over the age of 18 who underwent hip arthroscopy with preoperative as well as 2-year postoperative functional outcome scores were identified through the Multicenter Arthroscopic Study of the Hip (MASH) database. Patient demographics, procedure information, as well as patient reported outcome measures (PROMs) were collected along with CS index scores.

Results: 34 patients met inclusion criteria for our study. Preop MCS and iHOT as well as Postop MCS, showed moderate to strong negative correlations with CSI scores (-0.607, -0.573, and -0.756, respectively). VAS, PCS and MSC scores were significantly different preoperatively to postoperatively, ensuring alleviation of pain after hip arthroscopy. Subgroup analysis by stratifying CSI scores into 1 SD below the mean, within 1 SD of the mean, and above 1 SD showed significant differences across all 3 groups for preoperative MCS (p < 0.001), postoperative MCS (p = 0.001), and PSEQ2 (p = 0.015). Postoperative VAS pain approached significance but did not meet criteria of p < 0.05 (p = 0.062).

Conclusion: Increased postoperative CSI scores directly correlated with decreased preoperative and postoperative MCS scores and worse preoperative resilience. Recognizing the influence of CS on pain perception and resilience on coping with adversity in the recovery period may guide orthopaedic surgeons in developing comprehensive treatment plans to continue to improve surgical outcomes in hip arthroscopy.

Level of evidence: IV.