Does mobile-bearing have better flexion and axial rotation than fixed-bearing in total knee arthroplasty? A randomised controlled study based on gait

Midterm Survival of a Varus-Valgus Constrained Implant following One-Stage Revision for Periprosthetic Joint Infection: A Single-Center Study

Revision total knee arthroplasty (TKA) is challenging to perform in patients with periprosthetic joint infection (PJI) due to the difficulty of eradicating the infection and potential for bone and ligamentous deficits. The current study aimed to evaluate the midterm survival of varus-valgus constrained (VVC) implants used in one-stage revision TKA for chronic PJI at our institution. This retrospective analysis included 132 patients with chronic PJI who underwent one-stage revision using a VVC implant. The average follow-up was 51.6 months (range: 24-85 months). Five-year survival analysis was performed to set recurrent infection and mechanical failure as the end point. Hospital for special surgery (HSS) as functional outcomes was evaluated preoperatively and at the latest follow-up. A total of 12 patients (9.1%) underwent retreatment for reinfection (nine patients) and mechanical failure (three patients). The overall 5-year revision-free survival was 82.7%, the infection-free survival was 91.1%, and the mechanical failure-free survival was 98.3%. The preoperative HSS knee score improved from 35.6 points (range: 24.3-47.7 points) preoperatively to 76.8 points (range: 57.2-87.6 points) at the latest follow-up. Complications were identified in 20 patients (15.2%) which included aseptic osteolysis in 4 cases, acceptable flexion instability in 3 cases, arthrofibrosis in 2 patients, hematomas in 2 cases, calf intermuscular venous thrombosis in 6 patients, and femoral stem tip pain in 3 cases. This is the first study to report the outcomes of one-stage revision using VVC implants for knee PJI. Improved functional outcomes and good midterm survival are demonstrated at an average follow-up of 51.6 months.

Observations on the kinematic characteristics of the healthy side of the knee in stroke patients: A cross-sectional study

The abnormal gait of stroke patients not only severely limits the recovery of their walking ability, but also seriously affects their quality of daily life. Previous observational studies have focused too much on the observation of single degree of freedom and axial knee motion angles in stroke patients. Changes in the multi-degree of freedom and multi-axial joint angles of the knee have been less frequently observed, leading to somewhat limited conclusions. Therefore, the aim of this study was to use the Opti-knee motion test to analyze in real time the motion of the knee in all directions on the healthy side of stroke patients and to compare it with normal gait to provide a clinical basis for subsequent rehabilitation. In a cross-sectional study, 120 subjects (60 stroke patients were as the observation group and 60 healthy subjects as the control group) were studied. Both groups of subjects were tested for Opti-Knee tri-axial angles of motion of the healthy side of the knee, including flexion and extension, internal and external rotation, internal and external turning, anterior and posterior displacement, superior and inferior displacement, left and right displacement, maximum extension angle and maximum flexion angle. Compared with the control group, there were significant changes in the joint angles of flexion and extension, internal and external rotation, internal and external turning, maximum extension and maximum flexion of the knee on the healthy side in the observation group, and the differences were statistically significant [95%(37.22, 45.13), P = .01], [95%(9.51,13.67), P = .018], [95%(4.82,7.57), P = .049], [95%(4.12, 8.63), P = .019], [95%(51.68, 57.28), P = .0001]. However, there was no significant change in the angle of motion of the healthy side of the knee for anterior-posterior displacement, superior-inferior displacement and internal-external displacement in either group and the differences were not statistically significant [95%(1.16, 1.78), P = .72], [95%(0.85,1.32), P = .32], [95%(0.57, 0.88), P = .36]. This study confirms the importance of changes in the angle of motion of the knee on the side of the stroke patient in maintaining the stability of the knee joint. Therefore, their bilateral lower limb symmetry training should be paid attention to in the subsequent rehabilitation treatment.

A nationwide comparison of staggered and simultaneous bilateral knee arthroplasty during a single hospitalization: Trends, risks and benefits

Background

We aimed to: (1) perform a nationwide trend analysis of staggered and simultaneous bilateral knee arthroplasty (KA); (2) investigate patient demographics and hospital characteristics in two groups; and (3) compare the outcomes of two groups with a focus on complications, length of stay (LOS) and hospitalization costs.

Methods

Utilizing the Hospital Quality Monitoring System, we included patients who underwent bilateral KA during a single hospitalization between 2013 and 2019. Patient demographics and hospital characteristics were compared between two groups. Outcomes were compared between propensity-score matched groups using logistic and linear regression.

Results

During the study period, 6291 staggered bilateral KA and 6284 simultaneous bilateral KA were performed. From 2013 to 2019, the proportion of staggered bilateral KA increased from 32.74% to 59.08%. Patients who were older, were single, had more comorbidities and had a non-osteoarthritis indication for surgery tended to receive staggered bilateral KA. Compared with 3327 propensity-score matched patients undergoing simultaneous bilateral KA, patients undergoing staggered bilateral KA were associated with a significantly lower incidence of wound infection (odds ratio [OR] ​= ​0.22; 95% confidence interval [CI], 0.07–0.65), and readmission within 30 days (OR ​= ​0.73; 95%CI, 0.54–0.99) and 90 days (OR ​= ​0.70; 95%CI, 0.55–0.89). However, staggered bilateral KA had higher odds of blood transfusion (OR ​= ​1.20; 95%CI, 1.02–1.40) and deep venous thrombosis (DVT) (OR ​= ​2.62; 95%CI, 1.82–3.98). Moreover, staggered bilateral KA can lead to higher costs (108,316.21 Chinese yuan [CNY] vs 103,367.60 CNY) and longer LOS (17.29 days vs 12.18 days) than simultaneous bilateral KA.

Conclusion

Our study indicates that staggered bilateral KA has become more common than simultaneous bilateral KA in China. Compared to simultaneous bilateral KA, staggered bilateral KA was associated with a lower incidence of wound infection and readmission. Staggered bilateral KA may be an alternative for patients who can't tolerate simultaneous surgery.

The translational potential of this article: Our study indicates that staggered bilateral KA is a safe and economical option for elderly patients who require bilateral KA but are at high clinical risk. The rising proportion of staggered bilateral KA will be a new trend in bilateral KA.

Effect of Time After Injury on Tibiofemoral Joint Kinematics in Anterior Cruciate Ligament-Deficient Knees During Gait

Background:

Anterior cruciate ligament (ACL) injury can lead to changes in tibiofemoral kinematics during gait, but the detailed short-term kinematic changes after ACL injury are still unknown.

Purpose:

To measure tibiofemoral kinematics during gait in ACL-deficient (ACLD) knees over time after ACL injury.

Study Design:

Controlled laboratory study.

Methods:

The authors categorized 76 patients with unilateral ACLD knees into 4 groups based on the time from injury: <3 months (group 1), 3 to 6 months (group 2), >6 to 12 months (group 3), and >12 months (group 4). The controls were 20 participants with ACL-intact knees. Changes in the knee kinematics and range of motion during gait were compared among ACLD groups and those with ACL-intact knees.

Results:

Compared with controls, the range of motion of flexion in group 1 was significantly lower (6°; P = .033), and the mean knee flexion was significantly increased (0.7°-3.4°) in groups 1 to 4 (all P ≤ .004). There was more internal tibial rotation (2.9°-4.3°) in group 1 and 2, and more anterior tibial translation (4.3 mm) in group 1 during the stance or swing phases than in controls (P ≤ .049 for all). The mean internal tibial rotation and anterior tibial translation significantly decreased from group 1 to group 4 (P < .001 for both). Compared with controls, the mean medial tibial translation was significantly greater (1.2-2.5 mm) in all groups, and more medial tibial translations (2.4-3.7 mm) were observed during the stance phase in groups 1, 3, and 4 (P ≤ .047 for all).

Conclusion:

ACLD knees displayed a motion impairment walking strategy within 3 months, and a higher-flexion walking strategy increased with time after injury. Excessive anterior translation and internal rotation of the tibia tended to return to normal, while excessive medial translation of the tibia increased in ACLD knees after 6 months postinjury. These results may provide new insight into the compensatory mechanisms and risk factors for premature osteoarthritis in ACLD knees.

No difference between mobile and fixed bearing in primary total knee arthroplasty: a meta-analysis

PURPOSE

Both mobile (MB) and fixed (FB) bearing implants are routinely used for total knee arthroplasty (TKA). This meta-analysis compared MB versus FB for TKA in terms of implant positioning, joint function, patient reported outcome measures (PROMs), and complications. It was hypothesised that MB performs better than FB implants in primary TKA.

METHODS

This meta-analysis was conducted according to the 2020 PRISMA statement. In February 2022, the following databases were accessed: Pubmed, Web of Science, Google Scholar, Embase. All the randomized clinical trials (RCTs) comparing mobile versus fixed bearing for primary TKA were considered.

RESULTS

Data from 74 RCTs (11,116 procedures) were retrieved. The mean follow-up was 58.8 (7.5 to 315.6) months. The MB group demonstrated greater range of motion (ROM) (P = 0.02), Knee Society Score (KSS) score (P < 0.0001), and rate of deep infections (P = 0.02). No difference was found in implant positioning: tibial slope, delta angle, alpha femoral component angle, gamma femoral component angle, beta tibial component angle, tibiofemoral alignment angle, posterior condylar offset, radiolucent lines. No difference was found in duration of the surgical procedure. No difference was found in the following PROMs: Oxford Knee Score (OKS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), visual analogue scale (VAS), function and pain subscales of the KSS score. No difference was found in the rate of anterior knee pain, revision, aseptic loosening, fractures, and deep vein thrombosis.

CONCLUSION

There is no evidence in support that MB implants promote greater outcomes compared to FB implants in primary TKA.

LEVEL OF EVIDENCE

Level I.

Loss of Knee Flexion and Femoral Rollback of the Medial-Pivot and Posterior-Stabilized Total Knee Arthroplasty During Early-Stance of Walking in Chinese Patients

Background The medial-pivot (MP) prosthesis was developed to produce more physiological postoperative knee kinematics and better patient satisfaction than traditional prostheses, but outcomes are inconsistent in different studies of Caucasian patients. This study aimed to investigate the postoperative patient satisfaction and in vivo knee kinematics of the MP and posterior-stabilized (PS) prosthesis during gait activity in Chinese patients.

Methods A retrospective analysis of 12 patients was received for this study in each MP group and PS group. Patient-reported satisfaction level and Forgotten Joint Score (FJS) were evaluated with questionnaires. A dual fluoroscopic imaging system was used to investigate in vivo knee kinematics of MP and PS total knee arthroplasty (TKA) during treadmill walking at a speed of 0.4 m/s.

Results Comparable promising patient satisfaction and overall FJS (MP 60.7 ± 15.35 vs. PS 51.3 ± 17.62, p = 0.174) were found between the MP and PS groups. Peak flexion appeared at around 70% of gait cycle with values of 52.4 ± 7.4° for MP and 50.1 ± 3.6° for PS groups (no difference). Both groups maintained a stable position at the stance phase and began to translated anteriorly at toe-off with an amount of 4.5 ± 2.3 mm in the MP and 6.6 ± 2.7 mm in the PS (p = 0.08) group until late swing. The range of this external rotation motion was 5.9 ± 4.8 and 6.2 ± 4.1° (p = 0.79) for the MP and PS, respectively.

Conclusion A similar knee kinematics pattern characterized by a loss of early-stance knee flexion and femoral rollback during walking was observed in the MP and PS TKAs. Our study confirmed similar effectiveness of MP TKA compared to PS TKA in Chinese patients, while the change of knee kinematics of both implants during slow walking should be noted.