Valgus In Group Research Articles

The effects of sex hormones during the menstrual cycle on knee kinematics.

The effects of the menstrual cycle and sex hormones on knee kinematics remain unclear. The purpose of the study was to investigate the effects of the menstrual cycle and serum sex hormone concentrations on knee kinematic parameters of the 90°cutting in female college soccer athletes. Three female college soccer teams (53 subjects) participated in the study. During the first menstrual cycle, a three-step method was used to exclude subjects with anovulatory and luteal phase-deficient (LPD) (12 subjects). The subjects' menstrual cycle was divided into the menstrual phase, late-follicular phase, ovulatory phase, and mid-luteal phase (group 1, 2, 3, 4). In each phase of the second menstrual cycle, we used a portable motion analysis system to enter the teams and tested the sex hormones concentrations and knee kinematics parameters in three universities in turn. We found that subjects had a lower maximum knee valgus in group 4 compared with other groups. This meant that subjects had a lower biomechanical risk of non-contact anterior cruciate ligament (ACL) injury in the mid-luteal phase. There was no significant correlation between serum estrogen, progesterone concentration, and knee kinematic parameters. This meant that sex hormones did not have a protective effect. Future studies need to incorporate more factors (such as neuromuscular control, etc.) to investigate.

Intraoperative patellar maltracking and postoperative radiographic patellar malalignment were more frequent in cases of complete medial collateral ligament release in cruciate-retaining total knee arthroplasty

BackgroundPatellar maltracking after total knee arthroplasty (TKA) can lead to significant patellofemoral complications such as anterior knee pain, increased component wear, and a higher risk of component loosening, patellar fracture, and instability. This study was to investigate the preoperative and operative variables that significantly affect patellar tracking after cruciate-retaining TKA.MethodsWe studied 142 knee joints in patients who had undergone TKA: the knees were dichotomized based on postoperative patellar tracking, which was evaluated on patellar skyline, axial-projection radiographs: group 1, normal patellar tracking (lateral tilt ≤ 10° and displacement ≤ 3 mm) and group 2, patellar maltracking (lateral tilt > 10° or displacement > 3 mm). The patients’ demographic data and clinical and radiographic measurements obtained before and after surgery were compared between the two groups.ResultsPreoperative lateral patellar displacement was greater (4.1 ± 2.6 mm vs. 6.0 ± 3.5 mm), as was the frequency of medial collateral ligament (MCL) release (3/67 vs. 24/75) in group 2 than in group 1 (p < 0.001 and p < 0.001, respectively). The distal femur was cut in a greater degree of valgus in group 1 than in group 2. (6.3 ± 0.8° vs. 6.0 ± 0.8°) (p = 0.034).ConclusionsComplete release of the MCL during surgery was associated with patellar maltracking (logistic regression: p = 0.005, odds ratio = 20.592). Surgeons should attend to patellar tracking during surgery in medially tight knees.Level of evidenceRetrospective comparative study, level III.

Risk factors of postoperative valgus malalignment in mobile-bearing medial unicompartmental knee arthroplasty.

The aim of this observational study was to investigate the risk factors of postoperative valgus malalignment after mobile-bearing medial unicompartmental knee arthroplasty (UKA). We retrospectively evaluated radiographic and surgical characteristics in 122 consecutive Oxford phase 3 UKAs. According to postoperative hip-knee-ankle angle (HKAA), 24 knees were sorted into group valgus with HKAA > 180° and 98 knees were sorted into group non-valgus with HKAA ≤ 180°. Logistic regression was performed to analyze risk factors including age, gender, BMI, side, preoperative limb alignment HKAA, preoperative LDFA, MPTA, FTFA, thickness of polyethylene bearing insert, tibial prothesis size, femoral prothesis size, medial tibial cut thickness, thickness of distal femoral mill, prothesis angle of coronal, and sagittal plane. The mean mechanical preoperative HKAA of 174.39°±4.23° was corrected to 178.18°±3.49° postoperatively (t = - 13.45, p = 0.000). The mean of postoperative HKAA in valgus group and non-valgus group was 183.45 ± 2.21° and 176.88 ± 2.35°, respectively (t = 12.44, p = 0.000). After statistical analysis with univariate analysis, eight risk factor variables among 16 independent variables were identified as potential predictors with p value ≤ 0.1. Multivariate logistic regression analysis for these eight potential predictors revealed that tibial cut (p = 0.046), LDFA (p = 0.003), MPTA (p = 0.011), and FTFA (p = 0.008) were significant risk factors predicting postoperative valgus malalignment after mobile-bearing UKA. Preoperative smaller LDFA, FTFA, larger MPTA and less medial tibial cut thickness were significantly associated with postoperative valgus malalignment in mobile-bearing UKA.

Changes in hindfoot alignment after total knee arthroplasty in knee osteoarthritic patients with varus deformity.

Hindfoot alignment can affect the weight-bearing kinematics of the knee joint in patients undergoing total knee arthroplasty (TKA). This study evaluated the change in hindfoot alignment after TKA by prospectively analysing the correlation between the knee joint and the hindfoot deformity, the post-operative improvement in the hindfoot deformity, and the long-term post-operative changes in hindfoot alignment. This study included 195 knees from 117 patients with osteoarthritis who underwent TKA between 2012 and 2013. The mechanical alignment angle of the knee joint and the hindfoot alignment angle were measured preoperatively and 6weeks, 1, and 2years post-operatively. The patients were divided into two groups according to the severity of the preoperative knee joint deformity: <10° varus (group 1, N=81) and ≥10° varus (group 2, N=114). The preoperative and post-operative radiologic parameters of the axis of the knee joint and hindfoot were evaluated, and the results were compared. A Spearman correlation analysis was used to assess the differences in both the mechanical alignment and the hindfoot alignment pre- and post-operatively. After TKA, the hindfoot valgus deformity improved from 5.2° (±3.8) valgus to 2.1° (±3.9) valgus. At 6weeks post-operatively, the hindfoot alignment angle was 1.4° (±3.5) valgus and 2.5° (±4.1) valgus in group 1 and group 2, respectively; the difference between the two groups was not statistically significant. Hindfoot alignment showed greater valgus with increasing varus of the mechanical alignment of the knee joint preoperatively (-0.484, p<0.001) and post-operatively (-0.147, p=0.040). The post-operative 1- and 2-year hindfoot alignment angles were 2.2° (±4.2) valgus and 2.2° (±4.1) valgus, respectively. None of the differences between the post-operative hindfoot alignment angles were statistically significant. The stable improvement in the hindfoot deformity after TKA demonstrates that a valgus deformity of the hindfoot in a patient with a varus knee joint deformity does not require preoperative correction. In patients with a residual hindfoot deformity and pain 6weeks after TKA, active treatment should be considered because no further improvement can be expected. Prospective cohort study, Level II.

Computer-assisted unicompartmental knee arthroplasty using dedicated software versus a conventional technique

The aim of this study was to retrospectively compare the results of two matched-paired groups of patients who had undergone a medial unicompartmental knee arthroplasty (UKA) performed using either a conventional or a non-image-guided navigation technique specifically designed for unicompartmental prosthesis implantation. Thirty-one patients with isolated medial-compartment knee arthritis who underwent an isolated navigated UKA were included in the study (group A) and matched with patients who had undergone a conventional medial UKA (group B). The same inclusion criteria were used for both groups. At a minimum of sixmonths, all patients were clinically assessed using the Knee Society Score (KSS) and the Western Ontario and McMaster Osteoarthritis Index (WOMAC) index. Radiographically, the frontal-femoral-component angle, the frontal-tibial-component angle, the hip-knee-ankle angle and the sagittal orientation of components (slopes) were evaluated. Complications related to the implantation technique, length of hospital stay and surgical time were compared. At the latest follow-up, no statistically significant differences were seen in the KSS, function scores and WOMAC index between groups. Patients in group B had a statistically significant shorter mean surgical time. Tibial coronal and sagittal alignments were statistically better in the navigated group, with five cases of outliers in the conventional alignment technique group. Postoperative mechanical axis was statistically better aligned in the navigated group, with two cases of overcorrection from varus to valgus in group B. No differences in length of hospital stay or complications related to implantation technique were seen between groups. This study shows that a specifically designed UKA-dedicated navigation system results in better implant alignment in UKA surgery. Whether this improved alignment results in better clinical results in the long term has yet to be proven.

Comparison of Posterior Cruciate Ligament Retentionversus Substitution in PFCSigma Rotating-Platform Total Knee Arthroplasty

Purpose : The purpose of this study was to assess the results of posterior cruciate ligamentretaining and posterior cruciate ligament-sacrificing total knee arthroplasty using PFC Sigma rotating-platform (RP). Materials and Methods : The subjects for this study were 43 patients who had undergone total knee arthroplasties by means of PFC Sigma RPs from February 2002 to July 2002 and, thereafter, had been observed for a period of at least 36 months. Twenty-two of the patients were categorized to group I, which retained the posterior cruciate ligament and 21 to group II, which substituted for the ligament. All the patients were evaluated for pre- and post-operative ranges of motion, the Hospital for Special Surgery (HSS) knee rating system, and radiographic analysis. Results : The average flexion contracture was 6.5˚ (±1.0˚) in group I and 6.7˚ (±0.8˚) in group II pre-operatively, and 1.1˚ (±0.3˚) in group I and 0.9˚ (±0.2˚) in group II at the last follow-up. The average active range of knee motion improved from 87.6˚ (±6.5˚) in group I and 86.6˚ (±6.1˚) in group II pre-operatively, to 123.0˚ (±7.8˚) and 125.1˚ (±7.3˚), respectively, at the last follow-up. The average HSS score improved from 41.1˚ (±7.1˚) in group I and 40.3˚ (±5.3˚) in group II preoperatively, to 87.3˚ (±6.0˚) and 88.9˚ (±4.9˚), respectively, at the last follow-up. There was also improvement in the average tibio-femoral angle from 8.0˚ in varus to 5.7˚ in valgus in group I and from 10.9 in varus to 5.4˚ in valgus in group II. Radiolucent lines were observed in 4 cases from group I and in 1 case from the group II. No significant progressive periprosthetic osteolysis was observed in the follow-up radiographs of both groups. Conclusion : There were no clinical and radiographic differences between the posterior cruciate ligament-retention and ligament-substitution groups, which indicates the necessity for long-term observation.