TABLE III.
Univariable and Multivariable Analysis of Dislocation Risk Associated with Patient Factors by Procedure*
| Patient Factor | Primary THA | Revision THA | ||||
|---|---|---|---|---|---|---|
| Unadjusted HR (95% CI) | Adjusted HR (95% CI) | Adjusted P Value | Unadjusted HR (95% CI) | Adjusted HR (95% CI) | Adjusted P Value | |
| Age, per 10 years | 0.91 (0.86-0.97) | 0.92 (0.86-0.98) | 0.006 | 0.97 (0.92-1.02) | 1.00 (0.94-1.06) | 0.984 |
| Sex (ref. = female) | ||||||
| Male | 0.67 (0.57-0.79) | 0.73 (0.61-0.87) | <0.001 | 0.83 (0.72-0.95) | 0.80 (0.68-0.95) | 0.009 |
| BMI (ref. = normal) | ||||||
| <18.0 kg/m2 | 1.42 (0.72-2.78) | 1.22 (0.58-2.59) | 0.606 | 1.43 (0.85-2.42) | 1.36 (0.76-2.44) | 0.297 |
| 25.0-29.9 kg/m2 | 0.95 (0.77-1.17) | 1.07 (0.86-1.32) | 0.553 | 1.03 (0.87-1.22) | 1.03 (0.85-1.25) | 0.771 |
| 30.0-34.4 kg/m2 | 0.77 (0.61-0.97) | 0.88 (0.68-1.12) | 0.289 | 0.96 (0.79-1.16) | 0.94 (0.75-1.78) | 0.601 |
| 35.0-39.9 kg/m2 | 0.83 (0.61-1.12) | 0.93 (0.68-1.27) | 0.642 | 1.26 (0.99-1.60) | 1.37 (1.04-1.79) | 0.023 |
| ≥40.0 kg/m2 | 1.13 (0.82-1.56) | 1.22 (0.87-1.71) | 0.241 | 0.99 (0.73-1.35) | 0.92 (0.66-1.29) | 0.645 |
| Neurologic disease (ref. = no) | ||||||
| Yes | 1.57 (1.31-1.87) | 1.52 (1.26-1.84) | <0.001 | 1.46 (1.24-1.72) | 1.33 (1.10-1.62) | 0.004 |
| Spine disease (ref. = none) | ||||||
| Major† | 1.55 (1.17-2.05) | 1.52 (1.13-2.05) | 0.006 | 1.32 (1.02-1.71) | 1.39 (1.05-1.85) | 0.022 |
| Minor | 1.10 (0.93-1.30) | 1.18 (0.98-1.43) | 0.084 | 1.08 (0.93-1.25) | 1.06 (0.89-1.27) | 0.523 |
| Prior spine surgery (ref. = none) | ||||||
| Major‡ | 1.52 (0.81-2.84) | 1.21 (0.63-2.31) | 0.571 | 0.78 (0.35-1.74) | 0.61 (0.27-1.38) | 0.236 |
| Minor | 1.39 (0.99-1.96) | 1.28 (0.90-1.81) | 0.170 | 0.79 (0.51-1.23) | 0.62 (0.38-1.02) | 0.058 |
| Indication for primary THA (ref. = osteoarthritis) | ||||||
| Osteonecrosis | 1.50 (1.11-2.04) | 1.35 (0.99-1.83) | 0.055 | 1.29 (1.03-1.62) | 1.31 (1.01-1.69) | 0.041 |
| Acute fracture or nonunion | 165 (1.06-2.59) | 1.78 (1.12-2.82) | 0.015 | 1.08 (0.89-1.30) | 1.11 (0.89-1.37) | 0.355 |
| Inflammatory arthritis | 1.00 (0.47-2.12) | 0.86 (0.41-1.83) | 0.702 | 1.26 (0.97-1.62) | 1.19 (0.88-1.62) | 0.244 |
| Other | 1.94 (1.32-2.86) | 1.71 (1.15-2.54) | 0.008 | 1.32 (0.92-1.88) | 1.36 (0.87-2.12) | 0.175 |
| Indication for revision THA (ref. = aseptic loosening) | ||||||
| Dislocation | — | — | — | 2.09 (1.75-2.50) | 1.89 (1.49-2.40) | <0.001 |
| Wear/osteolysis | — | — | — | 1.12 (0.90-1.38) | 0.91 (0.72-1.15) | 0.438 |
| Fracture/nonunion | — | — | — | 1.43 (1.14-1.79) | 1.38 (1.05-1.81) | 0.019 |
| Infection | — | — | — | 1.30 (1.06-1.59) | 1.69 (1.35-2.12) | <0.001 |
| Operative approach (ref. = posterior) | ||||||
| Lateral | 0.62 (0.52-0.74) | 0.58 (0.48-0.70) | <0.001 | 0.89 (0.77-1.02) | 0.95 (0.81-1.11) | 0.515 |
| Direct anterior | 0.26 (0.16-0.43) | 0.27 (0.16-0.44) | <0.001 | 0.47 (0.07-3.38) | 0.37 (0.06-2.39) | 0.295 |
| Trochanteric osteotomy | 1.92 (1.22-3.01) | 1.77 (1.11-2.82) | 0.016 | 0.52 (0.41-0.66) | 0.56 (0.43-0.74) | <0.001 |
| Acetabular liner configuration (ref. = standard) | ||||||
| Elevated | 0.74 (0.54-1.02) | 0.63 (0.45-0.88) | 0.006 | 0.80 (0.64-1.00) | 0.74 (0.58-0.93) | 0.010 |
| Dual mobility | 1.08 (0.48-2.42) | 0.59 (0.26-1.33) | 0.205 | 0.59 (0.38-0.91) | 0.44 (0.28-0.69) | <0.001 |
| Constrained | — | — | 1.28 (1.05-1.58) | 0.67 (0.52-0.87) | 0.003 | |
| Femoral head diameter (ref. = ≤32 mm) | ||||||
| ≥36 mm | 0.70 (0.59-0.83) | 0.69 (0.57-0.85) | <0.001 | 0.84 (0.73-0.97) | 0.82 (0.70-0.97) | 0.023 |
| Acetabular revision (ref. = no) | ||||||
| Yes | — | — | — | 0.60 (0.53-0.68) | 0.60 (0.51-0.70) | <0.001 |
*
HR = hazard ratio, CI = confidence interval, THA = total hip arthroplasty, and BMI = body mass index.
†
Diseases resulting in stiffness or biological fusion.
‡
Operative spine fusion.