A total of 64 patients were included in the study, mean age 68.17±7.94 years, Body Mass Index (BMI) 26.52±4.22 kg/m2. Postoperative mFTA was much closer to the target values of 180°; And all the KSS knee score, VAS score and ROM were significantly improved compared with preoperation (p < 0.001) (Table 1).
Table 1 Preoperative and postoperative patient conditions.
|
mFTA
|
ROM
|
VAS
|
KSS
|
preoperative
|
189.31±5.08*
|
105.31±15.56
|
6.14±0.71
|
98.66±13.35
|
postoperative
|
181.21±2.40#
|
116.56±6.42#
|
0.27±0.48#
|
148.67±8.20#
|
VAS: visual analogue score;
KSS: knee society system score;
mFTA: mechanical femorotibial angle;
*: means that the preoperative mFTA is different from the target value by one-sample t-test (p < 0.05);
#: means that mFTA, ROM, VAS and KSS scores were statistically different (p < 0.05) in a paired samples t-test between Preoperative and postoperative.
88% of the mFTA, 92% of the LDFA and 95% of the MPTA angle were within the threshold of 3°. According to the results of correlation analysis, there was a positive correlation between the D value and the knee function (p < 0.05). The larger the mFTA deviation from target values, the lower the KSS scores, the poorer the knee function. (p = 0.027). The severity of pain intensity worse with increasing mFTA or LDFA divergence from target values (p = 0.004, 0.047) (Table 2).
Table 2 Correlation analysis of the postoperative outlier differences of each knee parameter with function.
|
|
mFTAa
|
LDFAb
|
MPTAc
|
Activity
|
r
|
-0.034
|
0.062
|
-0.001
|
|
p
|
0.790
|
0.628
|
0.994
|
VAS scores
|
r
|
0.356
|
0.249
|
0.164
|
|
p
|
0.004*
|
0.047*
|
0.196
|
KSS scores
|
r
|
-0.276
|
-0.062
|
-0.025
|
|
p
|
0.027*
|
0.628
|
0.844
|
VAS: visual analogue score;
KSS: knee society system score;
a: Difference between the postoperative mFTA and 180°;
b: postoperative difference between the postoperative LDFA and 90°;
c: the difference between the postoperative MPTA and 90°;
*:The data were statistically significant, p < 0.05.
The accuracy of femoral and tibial prosthesis were 48% and 73%, respectively; The mean intraoperative femoral side prosthetics were inserted 1.67±0.82 times, the tibial side were inserted 1.38±0.70 times; The number of tibial side prostheses was fewer (p = 0.009), and the tibial side prediction accuracy was greater (p = 0.004) (Table 3).
Table 3 Statistical analysis of the number of intraoperative prosthesis insertion trials.
insertion trials(time)
|
Femoral side (cases)
|
Tibial side (cases)
|
P
|
1
|
31(48%)
|
47(73%)
|
0.004
|
≤2
|
56(88%)
|
59(92%)
|
0.380
|
>2
|
8(13%)
|
5(8%)
|
0.388
|
%: Percentage of cases.
In patients with more than 2 inserts of femoral and tibial prosthesis, 92% of patients had flexion contracture deformity; One of the patients had a flexion deformity of 15°, a lax medial collateral ligament, and the largest deviation in tibia and femur model. Consideration of flexion deformity and ligament relaxation may have an impact on its prediction.
Case report:
A 68-year-old woman admitted to our clinic with left knee pain and limitation in knee flexion. Admission check: The left knee had a flexion contracture of 15°, and the ROM of the left knee was 15° (extension) to 90° (flexion). The left knee had a mild valgus deformity, and instability was observed in the stress tests. The preoperative KSS score was 75. Preoperative planning predicted a prosthesis size of ATTUNE size-3 by the AIKNEE software (Figure 2). Intraoperatively, it was adjusted to an ATTUNE size-6 prosthesis and the medial collateral ligament was reconstructed. Postoperative review of the left knee X-ray (Figure 3). The patients started with active and passive ROM exercises from the first postoperative day. Follow-up of the patient was performed at 1-month, 3-months, and 6-months after surgery.