Tibial Prosthesis Research Articles

The "blownknee" patient's stress fracture of distal tibial component after unilateral TKA: A case report.

Periprosthetic fractures (PPF) are rare complications of total knee arthroplasty (TKA). The most common PPF after TKA is supracondylar femoral fracture, which is a relatively rare complication that is usually associated with high-energy trauma, with a reported incidence ranging from 0.4 to 1.7% according to the AOANJRR. However, in TKA patients, it is rarer that the stress fracture around the tibial prosthesis occurs due to changes in the lower limb force line, increasing weight-bearing, and changes in walking gait. A 68-year-old woman visited our hospital with "both knees had aggravated pain and deformity for 8 years." TKA was performed first on the left knee and the patient was discharged within 1 week. Three months later, the patient complained of pain in the upper middle 1/3 part of the medial tibia for 2 weeks, which gradually worsened and affected weight-bearing. Physical examination showed that the left knee joint presented varus deformity, and the right valgus deformity, which diagnosed as osteoarthritis of both knees and was so-called "blownknee". The disease was initially diagnosed as osteoarthritis of both knees on first admission and PPF of the tibia in second. Three operations were performed on this patient. The first was TKA of the left knee, the second was open reduction and internal fixation of the PPF of the tibia 3 months after the first operation, and the third was TKA of the right knee. Until now, the patient has had no recurrent PPF, and the fracture is healing from the last X-ray. Clinicians should be aware of the possibility of PPF after TKA, especially in such patients, the most preferred surgical treatment method was open reduction and internal fixation of fractures using locking plates, and if the PPF with loosened implants, Revision TKA, or megaprosthesis was the better choice.

Investigation into the analysis method for assessing contact stress in joint prosthesis

Contact stress is the important cause of wear and failure of knee joint prostheses implanted in the human body during movement. The calculation of contact stress on joint prostheses is often inaccurate due to the deviation of joint position during activity. This paper proposes a correction method for contact stress based on finite element results. Firstly, the contact stress and contact radius between femoral and tibial prostheses of knee joint were calculated and analyzed by Hertz contact theory. Then, individualized finite element models based on the individualized geometry of the joint prosthesis and individualized loading were constructed, and the finite element contact stress was analyzed. The finite element results were calibrated utilizing the Hertz contact theory. Additionally, this study investigated the impact of three gait patterns (normal gait, medial thrust gait, and bouncing gait) on the contact stress experienced by the tibial insert. The research methods and results can provide ideas for theoretical analysis and finite element simulation of prosthetic joint contact, as well as offer theoretical support and analysis methods for evaluating the lifespan of prosthetic joints.

Analysis of the causes of primary revision after unicompartmental knee arthroplasty: A case series.

Unicompartmental knee arthroplasty (UKA) has great advantages in the treatment of unicompartmental knee osteoarthritis, but its revision rate is higher than that of total knee arthroplasty. To summarize and analyse the causes of revision after UKA. This is a retrospective case series study in which the reasons for the first revision after UKA are summarized. We analysed the clinical symptoms, medical histories, laboratory test results, imaging examination results and treatment processes of the patients who underwent revision and summarized the reasons for primary revision after UKA. A total of 13 patients, including 3 males and 10 females, underwent revision surgery after UKA. The average age of the included patients was 67.62 years. The prosthesis was used for 3 d to 72 months. The main reasons for revision after UKA were improper suturing of the surgical opening (1 patient), osteophytes (2 patients), intra-articular loose bodies (2 patients), tibial prosthesis loosening (2 patients), rheumatoid arthritis (1 patient), gasket dislocation (3 patients), anterior cruciate ligament injury (1 patient), and medial collateral ligament injury with residual bone cement (1 patient). The causes of primary revision after UKA were gasket dislocation, osteophytes, intra-articular loose bodies and tibial prosthesis loosening. Avoidance of these factors may greatly reduce the rate of revision after UKA, improve patient satisfaction and reduce medical burden.

Finite element analysis of sagittal angles of unicompartmental knee arthroplasty

BackgroundUnicompartmental knee arthroplasty is an effective treatment for knee osteoarthritis, but it has the risk of failure, and the installation position of the prosthesis is one of the factors affecting the failure. There are few biomechanical studies on the installation angle of unicompartmental knee prosthesis. MethodsConstructed a finite element model of a normal human knee joint, and the validity of the model was verified by stress and front anterior methods. The mobile-bearing unicompartmental knee arthroplasty femoral prosthesis was placed at 3° intervals from 0° sagittal plane to 15° flexion, and − 2° and 17°were established, and observing the biomechanical changes of components. FindingsMaximum peak stresses occurred at a sagittal mounting angle of −2° for the insert and the contralateral meniscus, with the tibia showing a maximum at 17° sagittal and the tibial prosthesis stress maximum occurring at 6° sagittal. As the sagittal plane angle of the femoral prosthesis increases and the osteotomy distance extends posteriorly, more bone is amputated during the osteotomy. The ratio of the distance from the tip of the anterior intramedullary nail to the anterior end of the osteotomy to the total anteroposterior length of the sagittal osteotomy ranged from 43.2% to 44.6%. InterpretationIn this paper, the more appropriate sagittal mounting position for the femoral prosthesis is between 9 and 12°, based on the amount of osteotomy and the peak stress of each component in a standing position.

Finite Element Analysis of the Effect of Femoral Prosthesis Varus and Valgus Angle Installation on the Lateral Compartment in Unicompartmental Knee Arthroplasty.

This study used finite element analysis (FEA) to investigate the effect of varus and valgus angle on the lateral compartment in unicompartmental knee arthroplasty (UKA). One patient who underwent UKA was enrolled as the subject. Thirteen working conditions of the femoral prosthesis were simulated at varus and valgus angles of 0°, 2°, 4°, 6°, 8°, 10°, and 12°. A load of 1,000 N was applied downward along the mechanical axis of the femur, and the highest stress values on the surface of the polyethylene liner, cancellous bone under the tibial prosthesis, cartilage of femur lateral condyle, lateral meniscus, and tibial lateral plateau cartilage in each model were recorded. The six highest points were used to calculate the mean value. The highest stress values on the surface of the polyethylene liner, cancellous bone under the tibial prosthesis, cartilage of femur lateral condyle, lateral meniscus, and tibial lateral plateau cartilage increased with an increase in the femoral prosthesis varus/valgus angle. As compared with the standard position of the femoral prosthesis, there was no significant difference in the surface stress values of the polyethylene liner, cancellous bone under the tibial prosthesis, cartilage of femur lateral condyle, lateral meniscus and tibial lateral plateau cartilage when the femoral prosthesis varus/valgus angle was less than 4° (p > 0.05). In addition, the stress magnitude on the polyethylene liner, cancellous bone under the tibial prosthesis, cartilage of femur lateral condyle, lateral meniscus, and tibial lateral plateau cartilage significantly increased when the femoral prosthesis varus/valgus angle was greater than 4° (p < 0.001). The optimal femoral prosthesis varus/valgus angle in UKA was less than 4°.

Tibial post loading increases the risk of aseptic loosening of posterior-stabilized tibial prosthesis.

Aseptic loosening is the primary cause of failure following posterior-stabilized total knee arthroplasty. It is unclear whether tibial post loading of posterior-stabilized prosthesis increases the risk of aseptic loosening of the tibial prosthesis. The purpose of this study is to investigate the biomechanical effects of tibial post loading on the tibial prosthesis fixation interface during level walking, squatting, stair descent, and standing up-sitting down activities. In this paper, finite element models with and without post were established to compare the effects of tibial post loading on the von Mises stress of the proximal tibia, shear stress of the cement, and the bone-prosthesis interface micromotion during four physiological activities. The tibial post loading had an insignificant influence on tibial biomechanics and bone-prosthesis interface micromotion during leveling walking activity. However, compared to the insert without post condition, tibial post loading significantly increased the maximum tibial von Mises stress, the maximum shear stress in the medial of cement, and the bone-prosthesis interface peak micromotion by 912.84%, 612.77%, and 921.09%, respectively, at the moment of the maximum flexion angle for the stair descent activity, and 637.92%, 351.43%, and 519.13%, respectively, at the moment of the maximum flexion angle for the standing up-sitting down activity. Tibial post loading increased the risk of postoperative aseptic loosening of tibial prosthesis in patients with posterior-stabilized total knee arthroplasty, and it was recommended that the post-cam contact mechanism of posterior-stabilized prosthesis should be optimized to reduce the biomechanical impact of tibial post loading on tibial prosthesis fixation.

Mid-term effects of unicompartmental knee arthroplasty combined with anterior cruciate ligament reconstruction for the medial compartment osteoarthritis with anterior cruciate ligament deficiency by proportioning with the pure medial compartment osteoarthritis

Objective: To evaluate the mid-term efficacy of one-stage unicompartmental knee arthroplasty (UKA) combined with anterior cruciate ligament (ACL) reconstruction in the treatment of medial compartment osteoarthritis (OA) with ACL deficiency. Methods: Retrospective cohort study. The clinical data of 13 patients (14 knees) who underwent UKA with ACL reconstruction for knee medial compartment OA combined with ACL deficiency in Wangjing Hospital of China Academy of Chinese Medical Sciences from January 2012 to January 2020 were retrospective analyzed. A 1∶1 proportioning study was conducted with 13 patients (14 knees) who underwent UKA due to medial compartment OA with intact ACL during the same period. The matching conditions were the same gender, age, surgical side, anesthesia method, comorbidities, and imaging lesions. There were 26 patients (28 knees) in the two groups, including 6 males (6 knees) and 20 females (22 knees), aged (58.9±4.2) years. The range of motion (ROM) and Oxford Knee Score (OKS) were used to evaluate the knee joint function at the last follow-up. The anteroposterior, lateral and axial X-ray films of the knee joint and the weight-bearing full-length X-ray films of the lower limbs were taken during follow-up. The hip knee ankle (HKA) angle, the posterior slope angle (PSA) of tibial prosthesis, and the anterior tibial translation (ATT) were recorded and compared between the two groups. The progression of lateral compartment OA, prosthesis loosening, and dislocation were evaluated. The mid-term follow-up clinical efficacy of the two surgical methods was compared, and the etiology of the patients was analyzed to verify the clinical efficacy and patient selection of one-stage UKA combined with ACL reconstruction. Results: The follow-up time of the two groups was (7.14±2.45) years. At the last follow-up, there was no significant difference in joint ROM between the combined group and the UKA group (120.90°±2.95° vs 122.29°±3.22°, P=0.260). There was no significant difference in OKS score between the two groups [(42.50±1.99) vs (43.21±2.26), P=0.380]. There was no significant difference in HKA angle and ATT distance between the two groups before operation (both P>0.05). At the last follow-up, the results were better than those before operation, and the differences were statistically significant (both P<0.05). At the last follow-up, there was no significant difference in HKA Angle between the combined group and the simple group (177.79°±1.25 ° vs 177.86°±1.29°, P=0.880). Tibial prosthesis PSA and ATT distance were not significantly different between the two groups [(4.57°±0.94° vs 4.50°±1.34°and (0.21±0.89) mm vs (0.14±1.35) mm, both P>0.05)]. There was no prosthesis loosening and obvious progression of lateral compartment OA in both groups at the last follow-up. Conclusion: For young patients with medial compartment OA secondary to ACL deficiency, UKA combined with ACL reconstruction is recommended, it can obtain good mid-term results.

The main cause of tibial prosthesis malalignment after total knee arthroplasty in Southern Chinese population

ObjectivesThis study aimed to determine the occurrence rate of malalignment of tibial prosthesis and explore the influencing factors. Methods296 patients from Southern China who underwent total knee arthroplasty (TKA) were selected as the research objects. Their general demographic data were recorded. The tibial bowing angle (TBA), tibial length, medial proximal tibial angle (MPTA), tibial plateau shift angle (TPSA), tibial bone loss, lateral distal tibial angle, and overall width of tibial plateau and widths of medial and lateral tibial plateau were measured before TKA. The tibial component coronal alignment angle (TCCA) was measured after the operation. Malalignment of the tibial prosthesis was defined as TCCA <87° or TCCA >93°. Tibial bowing was indicated by TBA >2°, and lateral bowing was recorded as +. The correlations of TCCA with demographic data and pre-operation imaging measurement parameters were statistically analyzed. ResultsBivariate correlation analysis revealed negative correlations between TCCA and TBA (r = −0.602, P < 0.001) and TPSA (r = −0.304, P < 0.001), and a positive correlation with MPTA (r = −0.318, P < 0.001). Multivariate linear regression analysis demonstrated a significant negative correlation between TCCA and TBA (P < 0.001). The occurrence rate of malalignment of tibial prosthesis was 12.37 %. The occurrence rates of malalignment were 22.54 % in the tibial bowing group and 6.87 % in the non-tibial bowing group, showing statistical differences (P < 0.001). ConclusionThe malalignment rate of tibial prosthesis among Southern Chinese patients is relatively high, possibly attributed to the tibial anatomy anomalies, particularly the tibial bowing. The entry point should be determined based on tibial morphology.

Utilizing Stems in Primary Total Knee Arthroplasty: Analysis of the Australian Orthopaedic Association National Joint Replacement Registry Data

BackgroundWe compared revision rates and reasons for revision for primary total knee arthroplasty (TKA) performed for osteoarthritis with and without tibial stem extensions. MethodsData from the Australian Orthopaedic Association National Joint Replacement Registry were used to compare all-cause revision, reason, and type of revision between primary TKA using stemmed tibial prostheses and non-stemmed prostheses. ResultsAll-cause revision for TKA with stem extension was higher for the first 6 months (hazard ratio [HR] 1.47; 95% confidence interval [CI]1.19 to 1.82; P < .001); while after 1.5 years TKA with stem extension had a lower rate of revision (HR 0.84; 95% CI 0.73 to 0.97; P = .01). Stemmed components were more likely to be revised for infection between 3 months and 1.5 years after surgery (HR 1.39; 95% CI 1.05 to 1.83; P = .02). The revision rate for aseptic loosening was lower in the stemmed group beyond 2 years (HR = 0.45; 95% CI 0.31 to 0.63; P < .001). Insert-only revision was higher in the stemmed group at all times (HR = 1.42; 95% CI 1.21 to 1.66, P < .001). Isolated tibial component revision was lower in the stemmed group at all times (HR 0.47; 95% CI 0.29 to 0.74; P = .001). Aseptic loosening for tibial component-only revision was significantly lower in the stemmed group at all times (HR 0.23; 95% CI 0.11 to 0.50; P < .001). ConclusionsPatients undergoing primary stemmed TKA have lower rates of all-cause revision beyond 1.5 years and tibial component-only revision at all times. Further investigation is required to preoperatively select patients that benefit from augmentation with stems.

Prediction of medial knee contact force using multisource fusion recurrent neural network and transfer learning.

Estimation of knee contact force (KCF) during gait provides essential information to evaluate knee joint function. Machine learning has been employed to estimate KCF because of the advantages of low computational cost and real-time. However, the existing machine learning models do not adequately consider gait-related data's temporal-dependent, multidimensional, and highly heterogeneous nature. This study is aimed at developing a multisource fusion recurrent neural network to predict the medial condyle KCF. First, a multisource fusion long short-term memory (MF-LSTM) model was established. Then, we developed a transfer learning strategy based on the MF-LSTM model for subject-specific medial KCF prediction. Four subjects with instrumented tibial prostheses were obtained from the literature. The results showed that the MF-LSTM model could predict medial KCF to a certain high level of accuracy (the mean of ρ = 0.970). The transfer learning model improved the prediction accuracy (the mean of ρ = 0.987). This study shows that the MF-LSTM model is a powerful and accurate computational tool for medial KCF prediction. Introducing transfer learning techniques could further improve the prediction performance for the target subject. This coupling strategy can help clinicians accurately estimate and track joint contact forces in real time.

机器人辅助全膝关节置换改善胫骨假体旋转对线的临床研究

机器人辅助全膝关节置换改善胫骨假体旋转对线的临床研究

The effect of different posterior inclinations of tibial component on tibiofemoral contact pressures after unicompartmental knee arthroplasty

BackgroundDifferent posterior inclinations of tibial component after unicompartmental knee arthroplasty (UKA) may lead to different biomechanical characteristics of the knee joint. This finite element study was designed to investigate the tibiofemoral contact pressures after UKA with different posterior inclinations of tibial component.MethodsFinite element model of a healthy knee joint was constructed, and mobile-bearing (MB) UKA models with 5 different posterior inclinations (3°, 5°, 7°, 9° and 11°) of tibial components were simulated. The maximum contact pressures of tibial plateau cartilage in the lateral compartment and polyethylene insert in the medial compartment were calculated based on the ground reaction force and the angle of the knee flexion obtained by 3D motion capture system.ResultsThe loading ratio of medial and lateral compartments during standing stance (medial 54.49%, lateral 45.51%) and tibial anterior displacement (134 N, 3.89 mm) of healthy knee was basically consistent with previous experimental data. The maximum contact pressures of the medial meniscus and lateral tibial plateau cartilage of the healthy knee during standing stance were 2.14 MPa and 1.57 MPa, respectively. At the static standing phase, the maximum contact pressures of the polyethylene insert decreased from 17.90 to 17.29 Mpa, and the maximum contact pressures of the tibial plateau cartilage in the lateral compartment increased from 0.81 to 0.92 Mpa following an increase in the posterior inclination of the tibial component. At the first peak of ground reaction force, the maximum contact pressures of polyethylene insert increased from 22.37 to 25.16 MPa, and the maximum contact pressures of tibial plateau cartilage in the lateral compartment increased from 3.03 to 3.33 MPa, with the increase in the posterior inclination of the tibial component. At the second peak of ground reaction force, the maximum contact pressures of polyethylene insert decreased from 2.34 to 2.22 MPa with the increase in posterior inclination of tibial component.ConclusionThe preoperative and postoperative finite element models of MB UKA were well established. The results showed that the maximum contact pressures of the polyethylene insert did not change significantly with the increase in the posterior inclination of the tibial prosthesis, while the maximum contact pressures of the tibial plateau cartilage of the lateral compartment increased when the posterior inclination of the tibial prosthesis was > 7°. Our results also show that the maximum contact pressures were greater with an excessive inclination angle (11°) of the tibial component, and the pressures of the tibial plateau cartilage in the lateral compartment were more concentrated on the posterior area. This study, therefore, proposes that excessive osteotomy should be avoided.

Stemmed Tibial Fixation for Primary Total Knee Arthroplasty in Obese Patients—A National Registry Study

BackgroundWe investigated if the use of augmented tibial fixation with stems in primary total knee arthroplasty (TKA) in obese patients was associated with a difference in reason for revision, type of revision, or overall revision rate. MethodsData from the Australian Orthopaedic Association National Joint Replacement Registry compared reason for revision, rate, and type of revision between primary TKA using stemmed tibial prostheses to nonstemmed prostheses, stratified by body mass index (BMI) and obesity. The cumulative percent revision was obtained using the Kaplan-Meier method, and Cox proportional hazards models estimated hazard ratios (HRs) adjusted for age and sex with 95% confidence intervals (CIs). All tests were 2-tailed at 5% statistical significance (P < .05). There were 66,508 procedures available for analyses. ResultsObese class 2 (BMI 35 to 39.99) had higher rates of revision in the stemmed group compared to the nonstemmed group (HR 1.44, 95% CI 1.00, 2.05, P = .047). There was no significant difference in revision rates between stemmed and nonstemmed tibial prostheses in any other BMI group. Primary TKA in obese patients (BMI ≥30) with a stem extension had a significantly higher rate of minor revisions compared to no stem extension (HR 1.31, 95% CI 1.03, 1.66, P = .025). There was no significant difference between stemmed and nonstemmed groups for major revision in obese patients and for minor or major revision in nonobese patients. ConclusionUsing a tibial stem during primary TKA in obese patients is not associated with a lower rate of revision.

Clinical evaluation of the first semi-active total knee arthroplasty assisting robot made in China: a retrospective propensity score-matched cohort study.

The precision of overall alignment and knee morphotype after robot-assisted total knee arthroplasty has been fully confirmed. This study aims to conduct a clinical evaluation of the first China-made semi-active total knee arthroplasty assisting robot. After a 1:2 propensity score matching, that is, a matched cohort study, patients were matched to the robot group (52 cases) and the conventional group (104 cases). The robot group received osteotomy according to preoperative planning, while the conventional group adopted preoperative planning based on the full-length radiograph and received conventional osteotomy. Perioperative clinical indicators, such as operation time, tourniquet time, hospitalization days, intraoperative bleeding, and hemoglobin level of the two groups were recorded; radiological indicators of postoperative prosthesis position, including hip-knee-ankle angle, frontal femoral component angle, frontal tibial component angle, lateral femoral component angle, and lateral tibial component angle were also recorded; deviations and outliers of the radiological indicators were calculated. Compared with the conventional group, the operation time and tourniquet time of the robot group were longer, and the postoperative hemoglobin level decreased less, the differences were statistically significant; the lateral tibial component angle of the conventional group was 80.9°±3.6°, which was smaller than 86.7 °±2.3° of the robot group, the difference was statistically significant ( P <0.001); except for lateral femoral component angle, the absolute deviations of the radiological indicators in the robot group were significantly smaller than that in the conventional group ( P ≤0.001); the outliers of the radiological indicators in the robot group were significantly smaller than that in the conventional group with a statistical difference ( P <0.05). Compared with the conventional group, the operation time of the robot group was relatively longer, but the perioperation blood loss was less. The robot group could better control the posterior inclination of the tibial prosthesis, and the absolute deviations and outliers of the prosthesis position were relatively smaller. There was no difference in short-term clinical score between the two groups.

COMPARATIVE STUDY OF TOTAL KNEE REPLACEMENT USING ALL POLYETHYLENE AND METAL BACKED TIBIAL PROSTHESIS

Introduction: Osteoarthritis is the result of mechanical and biological events that destabilize the normal processes of degradation and synthesis of articular cartilage chondrocytes, extracellular matrix, and subchondral bone. All-polyethylene (AP) tibial components were largely abandoned in favour of metal-backed (MB) components in the 1980s. metal backing is now the predominant design in total knee arthroplasty (TKA). The present study aimed to assess and compare the functional outcome, in patient with total knee replacement using all polyethylene and metal backed tibial prosthesis in Primary Total Knee Replacement. Material And Methods: Our is an analytical cross-sectional study in which we have included 36 patients with primary knee osteoarthritis kellgren –lawrence grade III, IV 18 patients in all poly group and 18 patients in metal backed group. In which during follow up X-rays and functional outcome was evaluated using the American Knee Society Score at 1, 3, and 6-month follow-ups for patients of both the groups and compared. Result: In all polyethylene groups the functional score at 1, 3 and 6 months were 51.39 + 8.1, 76.67 + 8.1 and 89.72 + 4.6 respectively. While in metal group, the mean functional scores were 50.28 + 5.8, 77.22 + 5.7 and 988.61 + 4.1 at 1 month, 3 months and 6 months respectively. The most common complication was stiffness in 13.9% of patients of both the groups followed by extension leg (5.6%), infection (2.8%) and proximal tibial fracture (2.8%) in both groups. In present study, 75% of the patient did not have any post operative complications among all study subjects. Conclusion: There is no statistically significant difference in clinical outcome between all polyethylene and metal backed, improved values in terms of functional and clinical scores preferably in both the group metal backed and all polyethylene group. This study is not without limitations. Even though it is prospective study, patients were followed for shorter duration only. Hence, a study with elegant methodology and long follow up period can accurately assess the efficacy of all polyethylene and metal backed prosthesis used in knee replacement surgery.

COMPARATIVE STUDY OF TOTAL KNEE REPLACEMENT USING ALL POLYETHYLENE AND METAL BACKED TIBIAL PROSTHESIS

COMPARATIVE STUDY OF TOTAL KNEE REPLACEMENT USING ALL POLYETHYLENE AND METAL BACKED TIBIAL PROSTHESIS

Aseptic loosening of tumor prostheses in distal femur after revision surgery: a retrospective study

BackgroundTumor prostheses of the distal femur after revision surgery is associated with high rates of aseptic loosening, which has introduced great challenges to the survival of patients, but only a few studies have evaluated their X-ray imaging. The purpose of this study was to analyze the risk factors for recurrence of aseptic loosening and make recommendations to reduce the incidence of aseptic loosening after revision surgery of tumor prostheses in the distal femur.MethodA retrospective analysis was performed on 23 patients who had revision surgery for distal femur prostheses due to aseptic loosening between June 2002 and June 2021. They were divided into two groups based on the condition of the prostheses after revision surgery: loosening group (9 patients) and control group (14 patients). Following the initial replacement, the length and diameter of the prosthetic intramedullary stem were measured through the standard full-length anteroposterior X-ray imaging of both lower limbs. The osteotomy length, femoral length and diameter, femoral intramedullary stem diameter, hip-knee-ankle angle (HKAA), mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), and so on were measured as well. Following that, statistical analysis was performed.ResultsPatients in the loosening group had statistically significant differences in the ratio of prostheses length to femur length (71.89 ± 6.62) and the ratio of intramedullary stem diameter to femoral diameter (25.50 ± 6.90) (P < 0.05), when compared to the control group. The HKAA (175.58 ± 2.78), mLDFA (94.42 ± 2.57), and the deviation angle between the lower limb alignment and the tibial prostheses force line (2.23 ± 1.09) in the loosening group were significantly different from those in the control group (P < 0.05) on postoperative radiographs of the entire length of the lower limbs. The lowest score in intramedullary manubrium I indicated less osteolysis, while the highest score in intramedullary manubrium III indicated the most serious osteolysis, and the difference was statistically significant (P < 0.05).ConclusionsOur study suggests that the use of longer and thicker intramedullary stems can effectively decrease the occurrence of aseptic loosening. Additionally, it is important to avoid using the original prostheses and reconstruct the standard line of lower limb force to further reduce the incidence of aseptic loosening. It is crucial to closely monitor the distal segment of the intramedullary stem for osteolysis after surgery.

A novel characterisation protocol of mechanical interactions between the ground and a tibial prosthesis for long jump

The mechanical study of Running Specific Prostheses (RSPs) is often limited to the blade. The setup developed and presented herein is a simple experiment, based on a mechanical testing machine and a camera, that assesses two indicators relevant to coaches and athletes in the field of athletics: secant stiffness and energy dissipation. The influence of four parameters on global prosthesis behaviour is evaluated: the load line offset, the prosthesis-ground angle, the sole type and the flooring type. The load line offset and the flooring type have little to no influence on their behaviour. The prosthesis-ground angle impacts the stiffness: an increase in the angle brings a significant decrease in stiffness, which strongly impacts the performance. The type of sole modifies the kinematics of the blade tip’s interaction with the ground. However, this effect is less likely to enhance the sports practice since athletics imposes the use of spikes. The camera images allow assessing the local behaviour of the sole, thus enabling to follow its strain through the compression process.

Trajectory of bearing movement during Oxford mobile-bearing unicompartmental knee arthroplasty using a kinematic alignment technique.

Trajectory of bearing movement during Oxford mobile-bearing unicompartmental knee arthroplasty using a kinematic alignment technique.

Uncemented Tibial Fixation Has Comparable Prognostic Outcomes and Safety Versus Cemented Fixation in Cruciate-Retaining Total Knee Arthroplasty: A Meta-Analysis of Randomized Controlled Trials

Cemented and uncemented fixation are the primary methods of tibial prosthesis fixation in total knee arthroplasty. However, the optimal fixation method remains controversial. This article explored whether uncemented tibial fixation has better clinical and radiological outcomes, fewer complications, and revision rates compared to cemented tibial fixation. We searched the PubMed, Embase, Cochrane Library, and Web of Science databases up to September 2022 to identify randomized controlled trials (RCTs) that compared uncemented total knee arthroplasty (TKA) and cemented TKA. The outcome assessment consisted of clinical and radiological outcomes, complications (aseptic loosening, infection, and thrombosis), and revision rate. Subgroup analysis was used to explore the effects of different fixation methods on knee scores in younger patients. Nine RCTs were finally analyzed with 686 uncemented knees and 678 cemented knees. The mean follow-up time was 12.6 years. The pooled data revealed significant advantages of uncemented fixations over cemented fixations in terms of the Knee Society Knee Score (KSKS) (p = 0.01) and the Knee Society Score-Pain (KSS-Pain) (p = 0.02). Cemented fixations showed significant advantages in maximum total point motion (MTPM) (p < 0.0001). There was no significant difference between uncemented fixation and cemented fixation regarding functional outcomes, range of motion, complications, and revision rates. When comparing among young people (<65 years), the differences in KSKS became statistically insignificant. No significant difference was shown in aseptic loosening and the revision rate among young patients. The current evidence shows better knee score, less pain, comparable complications and revision rates for uncemented tibial prosthesis fixation, compared to cemented, in cruciate-retaining total knee arthroplasty.