TY - JOUR
T1 - Does cup position differ between trabecular metal and titanium cups?
T2 - A radiographic propensity score matched study of 300 hips
AU - Laaksonen, Inari
AU - Hjelmberg, Natalie
AU - Gromov, Kirill
AU - Eskelinen, Antti E
AU - Rolfson, Ola
AU - Malchau, Henrik
AU - Troelsen, Anders
AU - Mäkelä, Keijo T
AU - Mohaddes, Maziar
PY - 2020/12
Y1 - 2020/12
N2 - Background and purpose - The use of trabecular metal cups in primary total hip arthroplasty (THA) is increasing, despite the survival of Continuum cups being slightly inferior compared with other uncemented cups in registries. This difference is mainly explained by a higher rate of dislocation revisions. Cup malpositioning is a risk factor for dislocation and, being made of a highly porous material, Continuum cups might be more difficult to position. We evaluated whether Continuum cups had worse cup positioning compared with other uncemented cups.Patients and methods - Based on power calculation, 150 Continuum cups from 1 center were propensity score matched with 150 other uncemented cups from 4 centers. All patients had an uncemented stem, femoral head size of 32 mm or 36 mm, and BMI between 19 and 35. All operations were done for primary osteoarthrosis through a posterior approach. Patients were matched using age, sex, and BMI. Cup positioning was measured from anteroposterior pelvic radiograph using the Martell Hip Analysis Suite software.Results - There was no clinically relevant difference in mean inclination angle between the study group and the control group (43° [95% CI 41-44] and 43° [CI 42-45], respectively). The study group had a larger mean anteversion angle compared with the control group, 19° (CI 18-20) and 17° (CI 15-18) respectively.Interpretation - Continuum cups had a greater anteversion compared with the other uncemented cups. However, the median anteversion was acceptable in both groups and this difference does not explain the larger dislocation rate in the Continuum cups observed in earlier studies.
AB - Background and purpose - The use of trabecular metal cups in primary total hip arthroplasty (THA) is increasing, despite the survival of Continuum cups being slightly inferior compared with other uncemented cups in registries. This difference is mainly explained by a higher rate of dislocation revisions. Cup malpositioning is a risk factor for dislocation and, being made of a highly porous material, Continuum cups might be more difficult to position. We evaluated whether Continuum cups had worse cup positioning compared with other uncemented cups.Patients and methods - Based on power calculation, 150 Continuum cups from 1 center were propensity score matched with 150 other uncemented cups from 4 centers. All patients had an uncemented stem, femoral head size of 32 mm or 36 mm, and BMI between 19 and 35. All operations were done for primary osteoarthrosis through a posterior approach. Patients were matched using age, sex, and BMI. Cup positioning was measured from anteroposterior pelvic radiograph using the Martell Hip Analysis Suite software.Results - There was no clinically relevant difference in mean inclination angle between the study group and the control group (43° [95% CI 41-44] and 43° [CI 42-45], respectively). The study group had a larger mean anteversion angle compared with the control group, 19° (CI 18-20) and 17° (CI 15-18) respectively.Interpretation - Continuum cups had a greater anteversion compared with the other uncemented cups. However, the median anteversion was acceptable in both groups and this difference does not explain the larger dislocation rate in the Continuum cups observed in earlier studies.
KW - Arthroplasty, Replacement, Hip/adverse effects
KW - Bone Anteversion/diagnostic imaging
KW - Equipment Failure Analysis
KW - Female
KW - Finland/epidemiology
KW - Hip Prosthesis/adverse effects
KW - Humans
KW - Image Processing, Computer-Assisted
KW - Male
KW - Metals/therapeutic use
KW - Middle Aged
KW - Postoperative Complications/diagnosis
KW - Prosthesis Design/adverse effects
KW - Prosthesis Failure/etiology
KW - Prosthesis Fitting/methods
KW - Radiography/methods
KW - Sweden/epidemiology
KW - Titanium/therapeutic use
UR - http://www.scopus.com/inward/record.url?scp=85087607069&partnerID=8YFLogxK
U2 - 10.1080/17453674.2020.1788290
DO - 10.1080/17453674.2020.1788290
M3 - Journal article
C2 - 32619155
VL - 91
SP - 682
EP - 686
JO - Acta Orthopaedica
JF - Acta Orthopaedica
SN - 1745-3674
IS - 6
ER -