Background
Methods
Patients and follow-up
Group 1, <50 (N = 1285) | Group 2, ≥50 (N = 1984) |
p value | |
---|---|---|---|
Sex (no. of hips) | |||
Male | 951 (74%) | 1426 (72%) | 0.1802 |
Female | 334 (26%) | 558 (28%) | |
Deceased#
| 10 (0.8%) | 29 (1.5%) | 0.0784 |
F/U mean years | 3.4 ± 2.98 | 2.8 ± 2.59 |
<0.0001* |
Lost to F/U | 17 (1.3%) | 23 (1.2%) | 0.6745 |
Case date range | 1/2001–8/2013 | – | |
Age (years) | 44 ± 6.02 | 57 ± 4.23 |
<0.0001* |
BMI | 28 ± 4.92 | 28 ± 4.56 | 0.0750 |
T-score | 0.26 ± 1.36 | −0.14 ± 1.18 |
<0.0001* |
Uncemented fixation (no. of hips) | 776 (60%) | 1380 (70%) |
<0.0001* |
10-year survivorship (no. of hips) | 1234 (96%) | 1924 (97%) | 0.1443 |
Diagnosis (no. of hips) | |||
Dysplasia | 149 (12%) | 214 (11%) | 0.4715 |
Osteoarthritis (OA) | 866 (67%) | 1589 (80%) |
<0.0001* |
Osteonecrosis (ON) | 107 (8.3%) | 63 (3.2%) |
<0.0001* |
Rheumatoid arthritis (RA) | 9 (0.7%) | 2 (0.1%) |
0.0039* |
Post-trauma | 40 (3.1%) | 20 (1.0%) |
<0.0001* |
Legg-Calve-Perthes disease (LCP) | 32 (2.5%) | 7 (0.4%) |
<0.0001* |
Slipped capital femoral epiphysis (SCFE) | 12 (0.9%) | 9 (0.5%) | 0.0930 |
Other | 22 (1.7%) | 21 (1.1%) | 0.1096 |
Implants (no. of hips) | |||
Corin Cormet 2000 | 187 (14%) | 185 (9.3%) |
<0.0001* |
Biomet ReCap™-Magnum™ hybrid | 330 (26%) | 409 (21%) |
0.0007* |
Biomet ReCap™-Magnum™ uncemented | 768 (60%) | 1390 (70%) |
<0.0001* |
ASA score | 1.6 ± 0.57 | 1.7 ± 0.58 |
<0.0001* |
Femoral component <48 mm (no. of hips) | 199/973 (20%) | 334/1641 (20%) | 0.9522 |
Femoral component size | 50.0 ± 3.92 | 50.2 ± 3.53 | 0.1793 |
Implant systems
Procedure
Variable | Group 1 | Group 2 |
p value |
---|---|---|---|
Length of incision (in.) | 4.4 ± 1.44 | 4.3 ± 0.77 |
0.0100* |
Operation time (min) | 106 ± 19.4 | 102 ± 28.8 |
<0.0001* |
Estimated blood loss (mL) | 208 ± 171 | 183 ± 137 |
<0.0001* |
Hospital stay (day) | 2.1 ± 1.11 | 2.1 ± 5.17 | 1.0000 |
Transfusion received (no. of cases) | 0 (0.0%) | 2 (0.1%) | 0.2543 |
Transfusion volume (cm3) |
–
| 375 ± 0 |
–
|
Outpatient (no. of cases) | 10 (0.8%) | 21 (1.1%) | 0.4179 |
Postoperative protocol
Metal ion testing
Normala
| Optimalb
| Acceptablec
| Problematicc
| Potentially toxicb
| |
---|---|---|---|---|---|
Unilateral | |||||
Co (μg/L) | <1.5 | <4.0 | 4–10 | 10–20 | >20 |
Cr (μg/L) | <1.5 | <4.6 | 4.6–10 | 10–20 | >20 |
Bilateral | |||||
Co (μg/L) | <1.5 | <5.0 | 5–10 | 10–20 | >20 |
Cr (μg/L) | <1.5 | <7.4 | 7.4–10 | 10–20 | >20 |
Clinical and radiographic analysis
Statistical methods
Results
Survivorship
Failures
Type | Group 1 | Group 2 |
p value |
---|---|---|---|
No. of cases | 1285 | 1984 | – |
1) Acetabular failures | |||
Adverse wear | 4 (0.3%) | 7 (0.4%) | 0.8415 |
Loose acetabular component | 6 (0.5%) | 4 (0.2%) | 0.1802 |
Failure of acetabular ingrowth | 10 (0.8%) | 9 (0.5%) | 0.2340 |
Acetabular component shift | 0 (0%) | 1 (0.1%) | 0.4237 |
2) Femoral failures | |||
Early femoral neck fracture | 5 (0.4%) | 15 (0.8%) | 0.1902 |
Loose femoral component | 12 (1.0%) | 9 (0.5%) | 0.0930 |
Femoral head collapse | 2 (0.2%) | 4 (0.2%) | 0.7642 |
3) Other failures | |||
Unexplained pain | 1 (0.1%) | 3 (0.2%) | 0.5552 |
Late infection | 2 (0.2%) | 0 (0%) | 0.0784 |
Early infection | 1 (0.1%) | 1 (0.1%) | 0.7566 |
Late fracture | 2 (0.2%) | 1 (0.1%) | 0.3320 |
Recurrent instability | 3 (0.2%) | 0 (0%) |
0.0316* |
Psoas tendonitis | 1 (0.1%) | 0 (0%) | 0.2150 |
Other failuresa
| 0 (0%) | 4 (0.2%) | 0.1074 |
Total failures | 48 (3.7%) | 58 (2.9%) | 0.2005 |
Complications and reoperations
Type | Group 1 | Group 2 |
p value |
---|---|---|---|
No. of cases | 1285 | 1984 | – |
Complications | |||
1) Acetabular complications | |||
Loose acetabular component | 1 (0.1%) | 0 (0%) | 0.2150 |
Acetabular component shift | 2 (0.2%) | 18 (0.9%) |
0.0071* |
2) Femoral complications | |||
Loose femoral component | 1 (0.1%) | 1 (0.1%) | 0.7566 |
Femoral component shift | 0 (0%) | 1 (0.1%) | 0.4237 |
3) Other complications | |||
Psoas tendonitis | 1 (0.1%) | 0 (0%) | 0.2150 |
Sciatic nerve palsy | 3 (0.2%) | 2 (0.1%) | 0.3421 |
Hip dislocation | 4 (0.3%) | 12 (0.6%) | 0.2420 |
Late fracture | 2 (0.2%) | 2 (0.1%) | 0.6599 |
Pulmonary embolus | 3 (0.2%) | 2 (0.1%) | 0.3421 |
Spinal headache | 2 (0.2%) | 1 (0.1%) | 0.3320 |
Embolic stroke | 1 (0.1%) | 2 (0.1%) | 0.8337 |
Unexplained pain | 0 (0%) | 3 (0.2%) | 0.1645 |
Psoas hematoma | 1 (0.1%) | 0 (0%) | 0.2150 |
Abductor tear | 0 (0%) | 3 (0.2%) | 0.1645 |
Deep vein thrombosis | 2 (0.2%) | 5 (0.3%) | 0.5619 |
Other complicationsa
| 1 (0.1%) | 9 (0.5%) | 0.0574 |
Type | Group 1 | Group 2 |
p value |
---|---|---|---|
No. of cases | 1285 | 1984 | – |
Reoperations | |||
Femoral neck fracture | 0 (0%) | 1 (0.1%) | 0.4237 |
Early fracture | 0 (0%) | 1 (0.1%) | 0.4237 |
Late fracture | 2 (0.2%) | 2 (0.1%) | 0.6599 |
Fascial healing defect | 1 (0.1%) | 0 (0%) | 0.2150 |
Psoas tendonitis | 1 (0.1%) | 1 (0.1%) | 0.7566 |
Late infection | 0 (0%) | 2 (0.1%) | 0.2543 |
Early infection | 2 (0.2%) | 4 (0.2%) | 0.7642 |
Wound dehiscence | 2 (0.2%) | 2 (0.1%) | 0.6599 |
Other causesa
| 2 (0.2%) | 0 (0%) | 0.0784 |
Ion data and adverse wear-related failure
Under 50 case study | ||||||||
---|---|---|---|---|---|---|---|---|
Variables | Group 1 (under 50) | Group 2 (over 50) |
p values between group 1 and group 2 | |||||
Unilateral (N = 494) | Bilateral (N = 331) |
p value | Unilateral (N = 836) | Bilateral (N = 559) |
p value | Unilateral 1 vs. 2 | Bilateral 1 vs. 2 | |
Co (μg/L) | 1.1 ± 0.83 | 1.8 ± 1.25 |
<0.0001* | 1.1 ± 0.93 | 1.9 ± 1.31 |
<0.0001* | 1.000 | 0.2633 |
Cr (μg/L) | 0.9 ± 0.84 | 1.6 ± 1.32 |
<0.0001* | 1.0 ± 0.93 | 1.5 ± 1.32 |
<0.0001* |
0.0498* | 0.2750 |
Follow-up date (years) | 4.4 ± 2.58 | 4.9 ± 2.75 |
0.0080* | 3.9 ± 2.38 | 4.4 ± 2.55 |
0.0002* |
0.0003* |
0.0062* |
No. (%) of patients tested | 825 (64%) | – | 1359 (70%) | – |
0.0108* | |||
No. (%) of levels converted | 117 (24%) | 72 (22%) | 0.5157 | 191 (23%) | 138 (25%) | 0.4295 | 0.7279 | 0.3173 |
Normal, no. (%) | 393 (80%) | 169 (51%) |
<0.0001* | 657 (79%) | 234 (42%) |
<0.0001* | 0.6745 |
0.0078* |
Optimal, no. (%) | 488 (99%) | 320 (97%) |
0.0366* | 815 (97%) | 533 (95%) |
0.0300* | 0.1052 | 0.3371 |
Acceptable, no. (%) | 6 (1.2%) | 11 (3.3%) |
0.0366* | 21 (2.5%) | 26 (4.7%) |
0.0300* | 0.1052 | 0.3371 |
Problematic, no. (%) | 0 (0%) | 0 (0%) | 1.000 | 0 (0%) | 0 (0%) | 1.000 | 1.000 | 1.000 |
Potentially toxic, no. (%) | 0 (0%) | 0 (0%) | 1.000 | 0 (0%) | 0 (0%) | 1.000 | 1.000 | 1.000 |
Clinical data
Variable | Group 1—under 50 | Group 2—over 50 |
p value |
---|---|---|---|
Preoperative | |||
HHS | 58 ± 6.47 | 49 ± 7.56 |
<0.0001* |
Postoperative | |||
HHS | 97 ± 6.80 | 97 ± 6.60 | 1.000 |
UCLA activity score | 7.6 ± 1.91 | 7.4 ± 1.90 |
0.0033* |
High-impact UCLA, no. of cases (%) | 230/539 (43%) | 377/1031 (37%) |
0.0183* |
VAS pain: regular | 0.2 ± 0.80 | 0.2 ± 0.74 | 1.000 |
VAS pain: worse | 1.5 ± 2.07 | 1.1 ± 1.78 |
<0.0001* |
Combined ROM | 258 ± 46.1 | 264 ± 41.9 |
<0.0001* |
Radiographic data | |||
AIA | 39.6 ± 8.14 | 39.6 ± 8.15 | 1.000 |
Under RAIL, no. of hips (%) | 1138/1238 (92%) | 1807/1918 (94%) |
0.0366* |
Radiolucency, no. of hips (%) | 0 (0.0%) | 3 (0.2%) | 0.1645 |
Osteolysis, no. of hips (%) | 0 (0.0%) | 0 (0.0%) | 1.000 |
Radiographic data
Surgical data
Discussion
Study | Procedure | Prosthesis | Date range | Diagnosis (years) | Patient cohort | Avg FU (years) | Survivorship | ||
---|---|---|---|---|---|---|---|---|---|
Hips | Female (%) | FU | Rate (%) | ||||||
Jameson et al. [51] | HRA | Birmingham | 2004–2007 | <55 | 254 | 39 | 2.3 | 3.8 | 97 |
Matharu et al. [45] | HRA | Birmingham | 1997–2006 | <50 | 447 | 28 | 10.1 | 10 | 96 |
Woon et al. [52] | HRA | Conserve Plus | 1996–2010 | <30 | 53 | 39 | 8.2 | 8 | 95 |
Amstutz et al. [53] | HRA | Conserve Plus | 1998–2007 | <50 | 350 | 25 | 5.5 | 5 | 97.8 |
Krantz et al. [44] | HRA | Conserve Plus and Durom | 2007–2008 | <30 | 24 | 32 | 4.2 | 4.9 | 100 |
Haddad et al. [23] | HRA | Birmingham | 1999–2002 | <55 | 40 | 25 | 12 | 10 | 100 |
Matharu et al. [54] | HRA | Conserve Plus and Corin Cormet 2000 | 2001–2007 | <25 + osteonecrosis | 20 | 50 | 5.2 | 8.6 | 100 |
Matharu et al. [54] | THA | Stryker Accolade II stem and Trident cup | 2001–2007 | <25 + osteonecrosis | 20 | 38 | 5.2 | 7.3 | 93 |
Wroblewski et al. [55] | THA | Charnley | 1962–1990 | <51 | 1434 | 61 | 15 | 17 | 83 |
Current study | HRA | Corin Surface and Biomet ReCap™ | 2008–2013 | <50 | 1285 | 26 | 3.4 | 12 | 96 |
Conclusions
-
In the largest (n = 1285) single series of hip arthroplasty ever published for patients under 50, MOM HRA exceeds the 2014 NICE implant survivorship criteria, with 96.5% at 10 years and 96.4% at 12 years.
-
Results in women have improved rapidly, reducing the disparity in outcomes between sexes; furthermore, after eliminating the initial Corin cohort, 10-year implant survivorship for men and women Biomet implants both exceed the 2014 NICE criteria independently at 99 and 97%, respectively.
-
There is no difference in survivorship by age among our patients (96.5 vs. 96.3% at 12 years for under and over 50, respectively).
-
AWRF is a rare complication (0.3%). Blood ion testing is an effective screening tool. When the acetabular component position meets RAIL guidelines, this failure mode is completely avoidable. None have occurred in 1530 consecutive cases since July 2009.