Patient disposition
The sampling frame consisted of 203 patients, 88% of whom who had undergone primary THA and 24% revision THA. Fifteen cases used HFPC-DMR-HA and 5 HFPC-DM-CEM acetabular cups and all twenty cases were included in the cohorts. Three (20%) and 2 patients (40%) were lost to 2-year follow-up, respectively (Fig. 2).
Sampling frame characteristics
Acetabular cups used in the sampling frame were 31 (15.3%) standard acetabular cups (STD) and 172 (84.7%) DM. DM were 15 (7.5%) HFPC-DMR-HA, 5 (2.5%) HFPC-DM-CEM and 152 (74.92%) other models (Fig. 2). The overall female/male ratio was 107/96 (53%/47%) (Table 1) and DM were used in non-significantly different frequencies in the two genders (54.1%/45.9% Fisher exact test p = 0.436).
Table 1
Cup | Total n (%) | female / male n (%) | age mean (sd) | primary THA n (%) | revision THA n (%) |
HFPC-DMR-HA | 15 (7.4) | 9 (60)/ 6 (40) | 77.3 (13.4) | 5 (33) | 10 (67) |
HFPC-DM-CEM | 5 (2.5) | 3 (60)/ 2 (40) | 77.6 (6.7) | 0 (0) | 5 (100) |
Other DM | 152 (74.9) | 81 (53) / 71 (47) | 71.8 (10.4) | 143 (94) | 9 (6) |
Standard | 31 (15.3) | 14 (45) /17 (55) | 50.2 (6.4) | 31 (100) | 0 (0) |
Total | 203 (100) | 107 (53) / 96 (47) | 69.1 (12.9) | 179 (88) | 24 (12) |
Mean age at the time of surgery was 69.1 [67.3, 70.9]. Patients treated with STD were significantly younger than patients treated with overall DM (mean difference 22.2 years [18.3, 26.1], p < 0.0001). Patients with HFPC-DMR-HA were significantly older than patients with other DM cups (mean difference 5 years) (rank sum test: p = 0.0196).
All STD were used for primary THA. All revision THAs were performed with DM and represented 14% of DM use. Revision surgery accounted for 100% of HFPC-DM-CEM, 67% HFPC-DMR-HA and 6% of other DM cups.
Patients undergoing primary THA were younger than those undergoing revision THA (mean difference: 9.6 years [5.4, 13.8], p < 0.0001).
The cohort median post-operative time to study follow-up date was 2.3 years (range: 1.7 ; 3.3) in HFPC-DMR-HA and 3.3 years (range: 1.7 ; 3.4) in HFPC-DM-CEM.
HFPC-DMR-HA cohort preoperative characteristics
Median patient age at the time of surgery was 85.6 years (range: 45.1 ; 93.3), female/male ratio was 60% / 40% and a median body mass index (BMI) of 24.6 kg.m− 2 (range: 14.5 ; 32.2) (Table 2). Revision THAs were due to loosening or fracture of the initial prosthesis (90%) and IPD (10%). Primary THAs were due to hip neck fracture or post-trauma necrosis (80%) and dysplasia (20%).
Table 2
Cohort demographics & operative details
HFPC-DMR-HA |
Demographics | n | mean | sd | min | p25 | p50 | p75 | max |
age (years) | 15 | 77.3 | 33.4 | 45.1 | 69.5 | 85.6 | 92.9 | 93.3 |
height (cm) | 15 | 164.9 | 9.9 | 150 | 157 | 165 | 173 | 180 |
weight (kg) | 15 | 67.6 | 18.4 | 33.5 | 52 | 70 | 82 | 93 |
BMI (kg/m²) | 15 | 24.4 | 4.8 | 14.5 | 21.1 | 24.6 | 28.3 | 32.2 |
Gender n (%) | male 6 (40) / female 9 (60) |
Side n (%) | right 10 (67) / left 5 (33) |
Prior hip surgery n (%) | 11 (73) |
Etiology n (%) - dysplasia - hip neck fracture or post-trauma necrosis - intra-prosthetic dislocation of a DM - prosthetic loosening or fracture - TOTAL | Primary 1 (6.7) 4 (26.7) 0 (0) 0 (0) 5 (33) | Revision 0 (0) 0 (0) 1 (6.7) 9 (60) 10 (67) | Total 1 (6.7) 4 (26.7) 1 (6.7) 9 (60) 15 (100) |
Operative details |
Bearing n (%) PE/ceramic 13 (87) PE/CoCr 2 (13) | Shell diameter (mm) range 48 ; 56 | Bone graft n (%) Cup 0 (0) Stem 0 (0) | Associated surgery n (%) none 7 (47) stem replacement 4 (27) other 4 (27) | Operative time (minutes) median & range 74 (40, 120) |
Intraoperative events/outcomes |
femoral cerclage wiring required n (%) 1 (6.7) | Hip stability n (%) excellent / medium: 14 (93.3) / 1 (6.7) |
HFPC-DM-CEM |
Demographics | n | mean | sd | min | p25 | p50 | p75 | max |
age (years) | 5 | 77.6 | 6.7 | 68.8 | 74.4 | 78.8 | 78.9 | 86.9 |
height (cm) | 5 | 161.4 | 9.5 | 148 | 158 | 160 | 170 | 171 |
weight (kg) | 5 | 67.6 | 10.7 | 53 | 66 | 66 | 70 | 83 |
BMI (kg/m²) | 5 | 25.8 | 2.4 | 22.8 | 24.2 | 25.8 | 28 | 28.4 |
Gender n (%) | male 2 (40) / female 3 (60) |
Side n (%) | right 2 (40) / left 3 (60) |
Prior hip surgery n (%) | 5 (100) |
Etiology n (%) - prosthetic loosening or fracture | Primary 0 (0) | Revision 5 (100) | Total 5 (100) |
Operative details |
Bearing n (%) PE/ceramic 13 (87) PE/CoCr 2 (13) | Shell diameter range (mm) 44 ; 64 | Bone graft n (%) Cup 1 (20) Stem 0 (0) | Associated surgery n (%) none 1 (20) stem replacement 3 (60) other 1 (20) | Operative time median & range (minutes) 87 (45, 120) |
Intraoperative events/outcomes |
Femoral cerclage wiring required n (%) 1 (20) | Hip stability n (%) excellent / medium: 4 (80) / 1 (20) |
HFPC-DM-CEM cohort preoperative characteristics
Median patient age at the time of surgery was 78.8 years (range: 68.8 ; 86.9), female/male ratio was 60% / 40% and a median body mass index (BMI) of 25.8 kg.m− 2 (range: 22.8 ; 28.4) (Table 2). All cases (100%) were revision surgeries due to loosening or fracture of the initial prosthesis.
HFPC-DMR-HA cohort operative characteristics
All cases were performed with a posterior surgical approach. Acetabular shell diameters ranged from 44 mm to 64 mm. All shells were secured with two pegs and a screw and without cement and no bone grafting was reported. PE liners were fitted with mostly with ceramic femoral heads (87%) while the others were fitted with CoCr heads and a wide range of femoral stems were used (Table 2).
Median surgical time was 74minutes (range: 40 ; 120). No patient required bone grafting. Associated surgery was stem replacement in 27% of cases. One case required femoral cerclage wiring. All presented excellent intraoperative stability.
HFPC-DM-CEM cohort operative characteristics
All cases were performed with a posterior surgical approach. Acetabular shell diameters ranged from 46 mm to 52 mm. All shells were cemented without pegs or screws and one case (20%) required autogenic bone grafting. PE liners were fitted with mostly with ceramic femoral heads (80%) while the others were fitted with CoCr heads and a wide range of femoral stems were used (Table 2).
Median surgical time was 87minutes (range: 45 ; 120). Bone graft was required in one HFPC-DM-CEM. Associated surgery was stem replacement in 60% of cases. One case required femoral cerclage wiring. All but one presented excellent intraoperative stability.
Primary endpoint: Implant survival
One patient with HFPC-DMR-HA required revision surgery at 3 month follow-up related to a surgical site infection. No other revision or death occurred throughout follow-up. Implant survival was 94.7% [68.1; 99.2%] with a total time at risk of 31.3 years (Fig. 3).
No HFPC-DM-CEM required revision surgery and no patient death occurred at two year follow-up, implant survival was 100% with a total time at risk of 1.6 years.
Secondary endpoints: Postoperative implant or procedure-related complications
With HFPC-DMR-HA, 10 adverse events were reported in 9 (60%) patients, including 1 IPD (6.7%) at 1-year follow-up (Table 2). The most frequent adverse events were 3 deaths (20%) unrelated to the procedure and implant as well as 2 surgical site infections (13.3%) There was also 1 fracture of the operated area (Vancouver class A) after the patient fell at 2-year follow-up but no prosthetic revision was required.[11–12]
In patients with HFPC-DM-CEM, no post-operative adverse event was reported.
Secondary endpoints: Functional outcomes
In patients with HFPC-DMR-HA, mean within-patient HHS increased from preoperative baseline to 1-year follow-up by 44.9 [29.6, 60.3] (Wilcoxon signed-rank test p < 0.003) and mean within-patient mHHS increased from baseline to 1-year follow-up by 48.1 [33.9, 62.4] (p < 0.002) and from baseline to 2-year follow-up by 54.2 [36.2, 72.3] (p < 0.008).
In patients with HFPC-DM-CEM, mean within-patient HHS increased from preoperative baseline to 1-year follow-up by 27.7 [-11.1, 66.6] and mean within-patient mHHS increased from baseline to 1-year follow-up by 27.2 [-11.9, 66.3] and from baseline to 2-year follow-up by 45.3 [15.3, 75.4] but the small amount of data at follow-up prevented drawing statistical conclusions.
Pre- and postoperative HHS and mHHS summary in Table 3
Table 3
HFPC-DMR-HA |
HHS | n | min | max | median | mean | sd | 95% CI |
HHS preoperative | 15 | 4 | 70 | 34 | 23.0 | 37.7 | [21.1, 46.6] |
HHS 1-year | 11 | 20 | 100 | 89 | 83.8 | 24.0 | [67.7, 99.9] |
range of motion preoperative | 15 | 0 | 5 | 4 | 3.0 | 2.1 | [1.9, 4.2] |
range of motion 1-year | 11 | 0 | 5 | 5 | 4.5 | 1.5 | [3.5, 5.5] |
mHHS: preoperative | 15 | 0 | 61 | 29 | 26.8 | 21.5 | [14.9, 38.7] |
mHHS: 1-year | 13 | 16 | 91 | 80 | 74.5 | 22.5 | [60.9, 88.1] |
mHHS: 2-year | 9 | 61 | 91 | 87 | 82.2 | 11.3 | [73.5, 90.9] |
Patients with post-operative severe adverse events n (%) |
description | Year 1 | Year 2 | Total |
death | 2 | 1 | 3 (20%) |
surgical site infection | 2 | 0 | 2 (13.3%) |
intra-prosthetic dislocation | 1 | 0 | 1 (6.7%) |
fall and fracture of the operated area (Vancouver class: A) | 0 | 1 | 1 (6.7%) |
other | 1 | 2 | 3 (20%) |
Total | 6 | 4 | 10 (67%) |
HFPC-DM-CEM |
HHS | n | min | max | median | mean | sd | 95% CI |
HHS preoperative | 5 | 29 | 61 | 58 | 50.0 | 13.8 | [32.9, 67.1] |
HHS 1-year | 5 | 18 | 100 | 86 | 77.7 | 34.2 | [35.2, 100] |
range of motion preoperative | 5 | 4 | 5 | 4 | 4.4 | 0.5 | [3.8, 5] |
range of motion 1-year | 5 | 5 | 5 | 5 | 4.9 | 0.1 | [4.8, 5] |
mHHS: preoperative | 5 | 21 | 53 | 49 | 41.6 | 13.4 | [24.9, 58.3] |
mHHS: 1-year | 5 | 9 | 91 | 77 | 68.8 | 34.2 | [26.3, 100] |
mHHS: 2-year | 3 | 71 | 91 | 80 | 80.7 | 10.0 | [55.8, 100] |
Patients with post-operative severe adverse events n (%) |
None |