Fig. 1
Femoral angle (α) and slope (γ), and tibial angle (β) and slope (δ) as measured on an anterior-posterior radiograph and on a lateral radiograph
Fig. 2
Flowchart of the patient selection process. (Signature is a technique that involves the use of patient specific instruments. UKA unicompartmental knee arthroplasty, KSS Knee Society Scores, TKA total knee arthroplasty)
Table 1
Patient demographics
|
Patient demographics |
Resident |
Surgeon |
P value |
|---|---|---|---|
|
Age (years) mean |
70.1 |
69.1 |
0.188 |
|
Gender: |
0.797 | ||
|
Male (%) |
36 |
38 | |
|
Female (%) |
64 |
62 | |
|
BMI (kg/m2), mean |
30.0 |
30.0 |
0.853 |
|
ASA classification (%): |
0.654 | ||
|
ASA 1 |
10 |
10 | |
|
ASA 2 |
65 |
68 | |
|
ASA 3 |
25 |
22 | |
|
ASA 4 |
0 |
0 | |
|
Patella component (%) |
67 |
68 |
0.820 |
BMI body mass index, ASA American Society of Anesthesiology
Table 2
Operation time and Knee Society Score 1 year postoperatively
|
Variable |
Resident (95% CI) |
Surgeon (95% CI) |
P value |
|---|---|---|---|
|
Operation time, minutes |
81.26 (47.9–115.3) |
71.3 (31.4–111.2) |
<0.001 |
|
KSS, 1 year postoperatively |
75.5 (46.3–104.6) |
77.5 (47.1–107.4) |
0.148 |
Table 3
Radiological position of the implants
|
Variable |
Resident (95% CI) |
Surgeon (95% CI) |
P value |
|---|---|---|---|
|
Tibial angle |
88.4 (84.5–92.4) |
88.5 (84.3–92.7) |
0.80 |
|
Femoral angle |
94.5 (85.8–103.2) |
94.4 (85.6–102.9) |
0.87 |
|
Tibial slope |
86.6 (79.9–93.4) |
86.6 (79.6–93.6) |
0.77 |
|
Femoral slope |
−3.2 (−10.7–4.3) |
−3.1 (−11.2–5.1) |
0.78 |
Table 4
Numbers and percentages of complications
|
Variable |
Resident (n = 220) |
Surgeon (n = 422) |
P value |
|---|---|---|---|
|
Hypovolaemic shock |
1 (0.45%) |
0 (0.00%) |
0.343 |
|
Hypotension |
3 (1.36%) |
1 (0.24%) |
0.119 |
|
Cardiac arrhythmia |
1 (0.45%) |
0 (0.00%) |
0.343 |
|
Pulmonary embolism |
0 (0.00%) |
1 (0.24%) |
1.000 |
|
Deep vein thrombosis |
3 (1.36%) |
1 (0.24%) |
0.119 |
|
Superficial surgical site infection |
3 (1.36%) |
7 (1.66%) |
0.774 |
|
Deep surgical site infection |
1 (0.45%) |
4 (0.95%) |
0.500 |
|
Wound defect |
1 (0.45%) |
1 (0.24%) |
1.000 |
|
Erysipelas |
1 (0.45%) |
0 (0.00%) |
0.343 |
|
Blistering |
0 (0.00%) |
3 (0.71%) |
0.555 |
|
Patella dislocation |
0 (0.00%) |
2 (0.48%) |
0.549 |
|
Loosening |
1 (0.45%) |
2 (0.48%) |
1.000 |
|
Disability in flexion/extension |
5 (2.27%) |
4 (0.95%) |
0.287 |
|
Peripheral nerve lesion |
1 (0.45%) |
2 (0.47%) |
1.000 |
|
Total |
21 (9.55%) |
33 (7.82%) |
0.651 |
Table 5
Reasons for revision
|
Revision |
Reason |
Surgery |
|---|---|---|
|
Group R | ||
|
Patient 1 |
Aseptic loosening tibia component |
Revision TKA |
|
Patient 2 |
Instability |
Change of insert |
|
Group S | ||
|
Patient 1 |
Patellofemoral complaints |
Patella component |
|
Patient 2 |
Loosening locking bar |
Revision of locking bar |
|
Patient 3 |
Patella dislocation, rotation of femur component |
Revision femur component, placement patella component, lateral release |
|
Patient 4 |
Deep infection |
Two-stage revision |
|
Patient 5 |
Aseptic loosening tibia component |
Revision tibia component |
|
Patient 6 |
Flexion and extension impairment |
Revision of insert |