Outcomes of Hip Arthroscopic Surgery in Patients With Tönnis Grade 1 Osteoarthritis at a Minimum 5-Year Follow-up: A Matched-Pair Comparison With a Tönnis Grade 0 Control Group

The acetabular labrum is theorized to be important to normal hip function by creating intra-articular fluid pressurization through the hip fluid seal. However, the effect of a labral tear or partial labral resection, and interventions including labral repair and labral reconstruction, on the hip fluid seal remains to be defined. The purpose of this study was to characterize intra-articular fluid pressurization in six labral conditions: intact, tear, repair (looped vs. through sutures), partial resection, reconstruction with iliotibial band, and complete resection. Eight cadaveric hips with a mean age of 47.8 years (SD 4.3, range 41-51) were included in the study. For each labral condition, the hip was compressed with a force of 2.7 times body weight (2,118 N) while intra-articular pressure was continuously measured with 1.0 × 0.3 mm pressure transducers. Peak intra-articular pressure measurements for each condition were normalized relative to the intact state. Statistical analyses were performed utilizing linear mixed-effects models with repeated measures analysis. Intra-articular fluid pressurization of the intact state varied from 78 to 422 kPa (mean 188 kPa ± SD 120). Labral tear, partial resection, and complete resection resulted in average pressurization of 75 ± 33, 53 ± 37, and 24 ± 18 %, respectively compared with the intact state. Through type labral repair resulted in significantly greater increases in pressurization from the labral tear state, compared with the looped type repair (median increase; +46 vs. -12 %, p = 0.029). Labral reconstruction resulted in a mean pressurization of 110 ± 38 % relative to intact state, with a significant 56 ± 47 % improvement in pressurization compared with partial labral resection (p = 0.009). Partial labral resection caused significant decreases in intra-articular fluid pressurization. Through type labral suture repair restored the fluid pressurization better than looped type repairs. Labral reconstruction significantly improved pressurization to levels similar to the intact state. This study demonstrated the effect of labral tears and partial resections on intra-articular fluid pressurization via the hip fluid seal, and it also demonstrated improvements in pressurization seen with through type labral repairs and labral reconstructions.

The purpose of this study was to provide evidence of validity for the Hip Outcome Score (HOS) as an outcome instrument in hip arthroscopy. We mailed the short form 36 (SF-36) and HOS questionnaires, as well as questionnaires regarding self-reported current activity level (normal, nearly normal, abnormal, or severely abnormal) and self-reported surgical outcome (excellent/good or fair/poor), to 337 subjects. Medical records were used to collect surgical and demographic information. Two groups were formed for those above and below the median age. Pearson correlation coefficients were used to assess the relation between the SF-36 scores and HOS scores. One-way analysis of variance was used to determine whether HOS scores differed according to current level of function, surgical outcome, and age. Of the subjects, 116 (34%) returned the questionnaire material. Nine of these subjects reported having surgery after August 2003 and were excluded. The data analysis was therefore performed on 107 subjects (32%). Within this group, there were 56 female patients (52%) and 51 male patients (48%), with a mean age of 42 years (median, 44.2 years; range, 14 to 79 years; SD, 14) and mean time to follow-up of 3.1 years (range, 2 to 4.6 years; SD, 0.49). The HOS activities of daily living (ADL) and sports subscales had a high correlation to the SF-36 physical function subscale (r = 0.86 and r = 0.84, respectively) and physical component summary score (r = 0.80 and r = 0.81, respectively) and a significantly (P < .005) lower correlation to the mental health subscale (r = 0.41 and r = 0.43, respectively) and mental component summary score (r = 0.17 and r = 0.18, respectively). HOS ADL and sports subscale scores were significantly different based on current activity level, surgical outcome, and age (P < .002). This study provides evidence of validity for the HOS in a sample of subjects at a mean of 3 years after hip arthroscopy. As hypothesized, the HOS scores had a high correlation to measures of physical function and a low correlation to measures of mental health. The HOS scores were different based on subjects' reported current activity level, reported surgical outcome, and age. The results of this study support the use of the HOS ADL and sports subscales as a self-report outcome instrument for hip arthroscopy. Level III, development of diagnostic criteria in a study of nonconsecutive patients.