Native Knee Research Articles

A Simple Surgical Technique for Correction of Varus Deformity in Advanced Osteoarthritis of Knees by Medial Femoral Condylar Sliding Osteotomy-Description of Procedure and short term Outcome-A Prospective Study.

Advanced osteoarthritis of knees with varus deformity consists of attenuation of lateral structures with contracture of the posteromedial structures and formation of medial osteophytes. The conventional step-wise medial and posteromedial release with measured resection may sometimes hinder achievement of perfectly balanced flexion and extension gaps with maintenance of flexion stability, without the use of a constrained prosthesis. Medial femoral epicondylar sliding osteotomy tailors the balancing to the need of the kinematics of the native knee and precludes the use of a constrained implant. 15 patients with Ahlbäck Grades III through V osteoarthritic changes at Howrah Orthopaedic Hospital were included in a prospective cohort case series with a minimum period of follow-up being 12months. Physical examination, clinical questionnaire and radiographic evaluation were done post-operatively for objectification by functional Knee Society and Oxford Knee Scores respectively. The mean post-operative femorotibial angulation ameliorated to a value of 3.73 ± 1.58° from 18.67 ± 4.2° in the pre-operative stage. The mean overall Range of Motion of operated knee was 109.87 ± 6.86° with no residual frontal laxity and/or laxity in the coronal plane. The mean amount of resection of tibial plateau in patients with severe varus deformity was kept to a minimum, 6.56mm from the least deficient portion of the lateral condyle. There were no complications as regards component loosening and/or surgical-site infection. The main objective of balancing a severely varus-afflicted knee is to preserve as much of the Medial Collateral Ligament as possible, to retain its check rein function and not jeopardise the stability. This is ensured by distalisation and posteriorizing the medial epicondyle by an incomplete osteotomy in addition to modest tibial resection fetching a non-isometric point of knee flexion. All osteotomies united by bony union and restoration of kinematic alignment. The limitation of this study however includes the lack of long-term results, such as late instability and polyethylene wear.

Management of Medial Femorotibial Knee Osteoarthritis in Conjunction with Anterior Cruciate Ligament Deficiency: Technical Note and Literature Review.

In recent years, there has been increased interest in the management of medial femorotibial knee osteoarthritis (OA) in conjunction with anterior cruciate ligament (ACL) deficiency. Traditional treatment modalities included conservative therapy, high tibial osteotomy with or without ACL reconstruction, and total knee replacement. Since younger patients with higher physical demands are more likely to suffer from this pathological condition, reduced invasiveness, faster recovery time, and improved knee kinematics are preferred to allow for satisfying clinical and functional outcomes. Thus, a new surgical strategy combining medial unicompartmental knee replacement (UKR) and ACL reconstruction has been proposed to allow bone stock preservation, to reduce surgical morbidity and recovery time, and ultimately to improve joint kinematics and clinical outcomes. Based on the data present in the literature, in the setting of unicompartmental OA in association with ACL deficiency, UKR combined with ACL reconstruction provided encouraging early results. Studies evaluating the outcomes of combined ACL reconstruction and UKR demonstrate promising results in select patient populations. Improved knee stability, pain relief, functional recovery, and patient satisfaction improved after surgery. Moreover, the combined approach offered advantages such as reduced surgical trauma, faster rehabilitation, and preservation of native knee anatomy compared with traditional treatment strategies. However, still, high-level studies on this topic are lacking; therefore, more comparative studies reporting long-term outcomes are needed to support the potential of this combined procedure to become mainstream. In this paper, we discuss the relevant features and rationale behind the indications and technique of this combined surgical procedure, to help surgeons choose the correct therapeutic approach for a patient with concomitant medial OA and ACL insufficiency. Continued advancements in surgical techniques, patient selection criteria, and rehabilitation strategies will further enhance the success of this combined approach, offering hope to individuals with concomitant ACL injuries and unicompartmental knee OA.

Medial Stabilised Total Knee Arthroplasty: Definition and Performance

Background Medial-stabilised total knee arthroplasty (MS-TKA) usage has increased significantly over the past decade with encouraging results. MS-TKA mimics the natural knee kinematics, providing superior antero-posterior stability as compared to cruciate-retaining or posterior-stabilised designs. Its proponents suggest that MS-TKA may provide the solution to the residual dissatisfaction seen in many patients following knee replacement surgery. Methods The literature was reviewed for critical analysis of the evidence for the biomechanics of the native knee and the clinical outcomes for MS-TKA. The history of the development of the medial-stabilised knee was also reviewed. Results MS-TKA were found generally to have similar revision rates to non-MS-TKA. Studies of knee function found either similar or improved function, which may be due to increased AP stability and a lack of paradoxical movement of femur over tibia which is seen in CR and PS designs. Conclusion This review highlights the key design features needed for a total knee arthroplasty to be termed as a medial-stabilised design, summarises current clinical and kinematic evidence including an overview of its development over the past three decades and sets out the next steps needed for meaningful evaluation of long-term real-world data of individual MS-TKA implants. With longer and more detailed follow-up data emerging as MS-TKA becomes more popular, a more thorough analysis of their performance will soon be possible.

The Vega advanced third generation posterior stabilized total knee arthroplasty system enables the restoration of range of motion for high demanding daily activities - A 5-years follow-up study.

The Vega System® PS (Aesculap AG, Tuttlingen, Germany) is an advanced, third generation fixed implant that aims to mimic natural knee kinematics by optimizing pivotal motion while reducing surface stress. This study evaluated mid-term survival and clinical outcomes, including range of motion (ROM) of the modern posterior stabilized implant in order to analyse whether this biomechanically successful implant reaches good results in situ. The first 100 patients to receive the Vega PS System for total knee arthroplasty were invited to take part in this single centre, single surgeon study. Of these, 84 patients were clinically assessed 5-6 years postoperatively. Data which was obtained during this follow-up examination included revision data, range of motion and clinical scores. The 5-year survival rate for exchange of any component was 97.6%, whereby two patients required replacement of the polyethylene gliding surface. Secondary patella resurfacing was performed in 7 patients. Significantly improved results in comparison to the preoperative state could be obtained at the follow-up: KOOS improved from 39.4 to 78.8, SF-12 PCS improved from 32.1 to 42 SF-12 MCS improved from 46 to 53.8 and patella pain improved from 2.7 to 0.3. The mean ROM of the 84 patients after 5 years was 133.1° and mean total KSS was 189.9. This study demonstrates a high survival rate of the Vega PS System® and significant improvements in clinical outcomes 5 years after implantation. The obtained mean ROM indicates that this implant provides good flexibility of the knee joint, allowing a high number of activities. However, due to the rate of secondary patella implantation, routine resurfacing of the patella for all PS TKA cases is highly recommended. The study was registered at clinicaltrials.gov (NCT02802085).

How to manage a native stiff knee.

Knee stiffness is a widely known and worrying condition in several postoperative knees. Less is known about native stiff knee. The aim of this manuscript is to summarize the available literature on native stiff knee epidemiology, classification and treatment. In 1989 stiff knee was defined as a knee with less than 50° of total range of motion. If range of motion is <30°, it is defined as an ankylosed knee. Knee stiffness can be divided into three main types: flexion contractures, extension contractures, and combined contractures. Different risk factors have been associated to native stiff knee and grouped into modifiable or not modifiable. Furthermore, risk factors can be divided into patients' related no patients'-related. Different treatment modalities can be indicated to treat knee stiffness, including manipulation under anesthesia (MUA), arthroscopic and open surgical release. When stiffness is associated with articular disruption TKA represent an option. TKA in native stiff knee can be challenging for the surgeon. Implant's choice and knee exposure are the first steps. In some cases, additional release and extensive can be considered. A stepwise approach and careful preoperative planning are mandatory to obtain long-term satisfactory outcomes. Native stiff knee is a rare but invalidating condition. Different treatment modalities have been proposed as treatment. However, considering that it is frequently associated to sever arthritis, TKA can be an option in painful stiff knees. Nature of knee stiffness necessitates a customized approach to ensure successful management and achieve satisfying outcomes.

Coronal Plane Alignment Classification of Arthritic Knees in a South Indian Population and Functional Outcome Comparison Post-mechanical Alignment Total Knee Arthroplasty.

Mechanical alignment has always been considered as the gold standard in total knee arthroplasty (TKA), but various other coronal alignment strategies have been proposed to enhance native knee kinematics and thus elevate patient satisfaction levels. Coronal plane alignment of the knee (CPAK) classification introduced by MacDessi is a simple yet comprehensive system to classify knees based on their coronal plane alignment. It categorizes knees into nine phenotypes based on medial proximal tibial angle (MPTA) and lateral distal femoral angle (LDFA). This study investigates the distribution of classification of primary arthritic knees (CPAK) types among arthritic knees in the South Indian population and compares the functional outcomes following total knee arthroplasty (TKA) using traditional mechanical alignment among various CPAK types. The research, spanning from September 2021 to August 2023, encompasses a comprehensive analysis of 324 patients with 352 knees in the first part and 48 patients with 72 knees in the second part of the study who underwent TKA, incorporating demographic data and radiological evaluations. Results indicate a predominant distribution of CPAK type 1, followed by type 2 and type 4 among the South Indian population. In the functional outcomes analysis, regardless of CPAK type, patients exhibited significant improvements in Knee Injury and Osteoarthritis Outcome Score (KOOS), Oxford Knee Score (OKS), and visual analog scale (VAS) scores post-operatively. CPAK distribution among the South Indian population is comparable to other Indian study and studies with an Asian population, but varies with studies among the White population. Significant improvement of functional outcome among all CPAK types signifies the robust nature of conventional mechanical alignment strategy. Thus, our study serves as an initial exploration into the knee phenotype of the South Indian population and findings contribute to ongoing research on optimal alignment strategies in knee arthroplasty, paving the way for future, more extensive studies in this dynamic field.

Small change in the arithmetic hip-knee-ankle angle during unicompartmental knee arthroplasty improves early postoperative functional outcomes.

The optimal lower-limb alignment after unicompartmental knee arthroplasty (UKA) remains controversial. This study aimed to investigate the optimal lower-limb alignment for functional improvement in the early post-UKA period. We hypothesized that a small change (Δ) in the arithmetic hip-knee-ankle (aHKA) angle during surgery would result in better postoperative knee function. This single-centered, retrospective study analyzed 91 patients (91 knees) who underwent UKA from April 2021 and December 2022. Preoperative and postoperative standing whole-leg radiographs were used to evaluate the mechanical HKA angle and aHKA angle. The aHKA angle was calculated from the medial proximal tibial angle (MPTA) and lateral distal femoral angle (LDFA). We defined restored aHKA angle as a postoperative aHKA angle within ± 3° of the preoperative aHKA angle. Functional improvement was evaluated using the preoperative and one-year postoperative Knee Society Scoring 2011 (KSS 2011). A multivariate regression analysis was performed to investigate the optimal lower-limb alignment for functional improvement. Postoperative restored aHKA angle (p = 0.020) was the only significant factor for improved KSS 2011 scores. Postoperative restored aHKA angle was obtained in 64 patients (70%). ΔMPTA (p < 0.001) and ΔLDFA (p = 0.037) were significant factors associated with a postoperative restored aHKA angle. UKA restores the native knee, including resurfacing constitutional alignment and medial collateral ligament tension. Minimal change in the aHKA angle during UKA improves the functional outcomes of the knee during the early postoperative period, consistent with the minimally invasive surgical concept of UKA.

Does arthroscopic or open washout in native knee septic arthritis result in superior post-operative function? A systematic review and meta-analysis of randomised controlled trials and observational studies

AimsSeptic arthritis (SA) of the native knee joint is associated with significant morbidity. This review compared post-operative functional outcomes (patient-reported outcome measures (PROMs) and range of movement (ROM)) following arthroscopic washout (AW) and open washout (OW) amongst adult patients with SA of the native knee. The need for further operative intervention was also considered.MethodsElectronic databases of PubMed, MEDLINE, Embase, Cochrane, Web of Science and Scopus were searched between 16 February 2023 and 18 March 2023. Randomised controlled trials (RCTs) and comparative observational analytic studies comparing function (reflected in PROMs or ROM) at latest follow-up following AW and OW were included. A narrative summary was provided concerning post-operative PROMs. Pooled estimates for mean ROM and re-operation rates were conducted using the random-effects model. The risk of bias was assessed using the Cochrane risk-of-bias assessment tool-2 for RCTs and the Risk of Bias in Non-Randomized Studies of Interventions tool for observational analytic studies.ResultsOf 2580 retrieved citations, 7 articles (1 RCT and 6 cohort studies) met the inclusion criteria. Of these, five had some concerns/moderate risk of bias, and two had serious risk. There was a slight tendency for superior mean PROMs following AW compared with OW, but due to small effect sizes, this was unlikely clinically relevant. Additionally, the use of four different PROMs scales made direct comparisons impossible. AW was associated with superior ROM (mean difference 20.18° (95% CI 14.35, 26.02; p < 0.00001)), whilst there was a tendency for lower re-operation requirements following AW (OR 0.64, 95% CI 0.26, 1.57, p = 0.44).ConclusionsAW was associated with equivalent to superior post-operative function and lower requirement for further intervention compared with OW. Results need to be interpreted cautiously, taking into consideration the methodological and clinical heterogeneity of the included studies.Systematic review registrationPROSPERO 2022, CRD42022364062.

The effect of different alignment strategies on trochlear orientation after total knee arthroplasty.

When planning and delivering total knee arthroplasty (TKA), there are multiple coronal alignment strategies such as functional alignment (FA), kinematic alignment (KA), mechanical and adjusted mechanical alignment (MA, aMA). Recent three-dimensional and robotic-assisted surgery (RAS) studies have demonstrated that KA potentially better restores the trochlear anatomy than MA. The purpose of this study was to compare the restoration of the native trochlear orientation in patients undergoing RAS TKA using fourdifferent alignment strategies. It was hypothesised that FA would result in the lowest number of outliers. This is a prospective study of 200 patients undergoing RAS-TKA with a single implant. All patients were analysed for MA and KA prebalancing, and 157 patients received aMA and 43 patients FA with intraoperative balancing. Preoperative transverse computed tomography scans were used to determine the posterior condylar axis (PCA), lateral trochlear inclination (LTI) angle, sulcus angle (SA) and anterior trochlear line (ATL) angle. Implant measurements were obtained using a photographic analysis. Intraoperative software data combined with implant data and preoperative measurements were used to calculate the differences. Outliers were defined as ≥3° of alteration. Trochlea dysplasia was defined as LTI < 12°. Native transepicondylar PCA had a median of 2°, LTI 18°, SA 137°, ATL 4°. LTI outliers were observed in 47%-60% of cases, with KA < FA < aMA < MA. For ATL, the range of outliers was 40.5%-85%, KA < FA < aMA < MA. SA produced 81% of outliers. Of all median angle values, only LTI when using KA was not significantly altered compared to the native knee. There is a significant alteration of trochlear orientation after TKA, regardless of the alignment strategy used. KA produced the lowest, but a substantial, number of outliers. The uniform design of implants causes the surgeon to compromise on balance in flexion versus trochlear position. The clinical relevance of this compromise requires further clinical investigations. Level II, prospective cohort study.

Automatic measurement of lower limb alignment in portable devices based on deep learning for knee osteoarthritis

BackgroundFor knee osteoarthritis patients, analyzing alignment of lower limbs is essential for therapy, which is currently measured from standing long-leg radiographs of anteroposterior X-ray (LLR) manually. To address the time wasting, poor reproducibility and inconvenience of use caused by existing methods, we present an automated measurement model in portable devices for assessing knee alignment from LLRs.MethodWe created a model and trained it with 837 conforming LLRs, and tested it using 204 LLRs without duplicates in a portable device. Both manual and model measurements were conducted independently, then we recorded knee alignment parameters such as Hip knee ankle angle (HKA), Joint line convergence angle (JCLA), Anatomical mechanical angle (AMA), mechanical Lateral distal femoral angle (mLDFA), mechanical Medial proximal tibial angle (mMPTA), and the time required. We evaluated the model’s performance compared with manual results in various metrics.ResultIn both the validation and test sets, the average mean radial errors were 2.778 and 2.447 (P<0.05). The test results for native knee joints showed that 92.22%, 79.38%, 87.94%, 79.82%, and 80.16% of the joints reached angle deviation<1° for HKA, JCLA, AMA, mLDFA, and mMPTA. Additionally, for joints with prostheses, 90.14%, 93.66%, 86.62%, 83.80%, and 85.92% of the joints reached that. The Chi-square test did not reveal any significant differences between the manual and model measurements in subgroups (P>0.05). Furthermore, the Bland-Altman 95% limits of agreement were less than ± 2° for HKA, JCLA, AMA, and mLDFA, and slightly more than ± 2 degrees for mMPTA.ConclusionThe automatic measurement tool can assess the alignment of lower limbs in portable devices for knee osteoarthritis patients. The results are reliable, reproducible, and time-saving.

Navigating the Divide: A Comprehensive Review of the Mechanical and Anatomical Axis Approaches in Total Knee Replacement.

This comprehensive review explores the mechanical and anatomical axis approaches in total knee replacement (TKR) surgery, addressing the ongoing debate within the orthopedic community. Emphasizing the significance of TKR in alleviating knee-related disorders, this review underscores the pivotal role of accurate alignment in achieving optimal surgical outcomes. The purpose is to navigate the divide between the well-established mechanical axis approach, focusing on a straight-line alignment, and the anatomical axis approach, aligning with natural knee landmarks. The analysis delves into the advantages, disadvantages, and clinical implications of each approach, offering a nuanced perspective on their efficacy. The conclusion emphasizes a patient-centric approach, recommending the adoption of hybrid strategies and the incorporation of emerging technologies for enhanced precision. The future of TKR aligns with personalized medicine, leveraging advancements in computer-assisted navigation, robotics, and patient-specific implants. Ongoing professional development and interdisciplinary collaboration are crucial for surgeons, and as the field evolves, innovations in artificial intelligence, imaging, and 3D printing are expected to shape the trajectory of TKR alignment approaches.

Scan-Free and Fully Automatic Tracking of Native Knee Anatomy from Dynamic Stereo-Radiography with Statistical Shape and Intensity Models.

Kinematic tracking of native anatomy from stereo-radiography provides a quantitative basis for evaluating human movement. Conventional tracking procedures require significant manual effort and call for acquisition and annotation of subject-specific volumetric medical images. The current work introduces a framework for fully automatic tracking of native knee anatomy from dynamic stereo-radiography which forgoes reliance on volumetric scans. The method consists of three computational steps. First, captured radiographs are annotated with segmentation maps and anatomic landmarks using a convolutional neural network. Next, a non-convex polynomial optimization problem formulated from annotated landmarks is solved to acquire preliminary anatomy and pose estimates. Finally, a global optimization routine is performed for concurrent refinement of anatomy and pose. An objective function is maximized which quantifies similarities between masked radiographs and digitally reconstructed radiographs produced from statistical shape and intensity models. The proposed framework was evaluated against manually tracked trials comprising dynamic activities, and additional frames capturing a static knee phantom. Experiments revealed anatomic surface errors routinely below 1.0 mm in both evaluation cohorts. Median absolute errors of individual bone pose estimates were below 1.0 or mm for 15 out of 18 degrees of freedom in both evaluation cohorts. Results indicate that accurate pose estimation of native anatomy from stereo-radiography may be performed with significantly reduced manual effort, and without reliance on volumetric scans.

Bi-cruciate retaining total knee arthroplasty is here to stay: A consecutive series transitioning from manual instrumentation to enabling technologies.

Bicruciate-retaining (BCR) total knee arthroplasty (TKA) has seen renewed interest due to the potential for more natural knee kinematics with anterior cruciate ligament (ACL) retention. The present study attempts to determine differences in the 2-year survivorship and patient-reported outcomes between two surgical strategies (traditional instrumentation versus robotics) applied to the extensive use of a modern, 2nd generation BCR TKA design. We performed a retrospective study with prospectively collected data of 113 patients who underwent primary TKA between 2018 and 2020 using a 2nd generation BCR TKA implant. Patient demographics, PROMS, and intra/post-operative complications were collected. Patients were also evaluated according to the use or not of robotics. A Kaplan-Meier analysis was used to evaluate revision-free survival at follow up. 102 patients were enrolled: 90 received traditional surgery and 12 robotic-assisted surgery. The mean age was 68years (SD 7.76) with an average BMI of 29.6 kg/m2 (SD 3.56). The mean follow up (FU) was 32.4 ± 6.2 months (range 24-45months). Survivorship at 2 years was 98% (95% CI: 92.4-99.5). Revisions/reoperations were performed for anterior cruciate ligament (ACL) tear (1/4), pain (1/4), arthrofibrosis (1/4) and acute periprosthetic joint infection (PJI) (1/4). At final FU, 92 patients (90.2%) considered themselves satisfied, showing a mean OKS of 40.6 (SD 5.1) and a mean FKS of 76.7 (SD 11.8). No differences in the outcome were found between traditional and robotic-assisted procedures. The modern BCR design evaluated in this study achieved excellent results in terms of implant survivorship, low rate of reoperation and clinical results, independently from the use of enabling technologies.

Incidence of patella baja and pseudopatella baja in aseptic revision total knee arthroplasty.

There are two variants regarding the low location of the patella in relation to the tibio-femoral joint line: patella baja (PB) and pseudo-patella baja (PPB). The purpose of this study is to investigate the incidence of PB and PPB in a cohort of patients that underwent revision total knee arthroplasty (rTKA) for aseptic reasons and describe any differences in each group's ROM. This retrospective study included 114 patients that underwent aseptic revision TKA surgery between 2017 and 2022. Patients were revised either for stiffness (Group 1) or aseptic loosening/instability (Group 2). The Insall-Salvati ratio (ISR) and Blackburne-Peel ratio (BPR) were used to evaluate the patellar position. ISR < 0.8 defined PB, while cases with ISR ≥ 0.8 and BPI < 0.54 were defined as PPB. ROM was measured and a subanalysis was conducted to investigate the progression of the values of ISR and BPR. 55 patients comprised Group 1, and 59 patients comprised Group 2. Overall, 13 cases (11.4%) had PB before rTKA and 24 (21%) had PB after rTKA. Cases with PPB were 13 (11.4%) before and 34 (29.9%) after rTKA. Group 1 patients presented with more PB before and after rTKA (12.8% vs 10.2% and 27.3% vs 15.2% respectively). However, after rTKA Group 1 patients presented with less PPB (20%) compared to Group 2 (39%) (p = 0.02). In Group 1, patients with PPB after rTKA had less ROM compared to those without PPB [83.2 (± 21.9) vs 102.1 (± 19.9) (p = 0.025)]. The subanalysis (69 patients) showed a statistically significant decrease in ISR before and after rTKA (p = 0.041), and from the native knee to post-rTKA (p = 0.001). There was a statistically significant decrease in BPR before and after rTKA (p = 0.001) and from the native knee to both pre- and post-rTKA (p < 001). After undergoing rTKA, the incidences of both patella baja (PB) and pseudo-patella baja (PPB) increased. Stiffness in the knee was associated with a higher incidence of PB, while non-stiffness cases showed a significantly higher incidence of PPB. Patients with stiff knees and PPB after rTKA experienced a significant reduction in range of motion (ROM). Additionally, the study revealed a noteworthy decrease in ISR and BPR with each subsequent surgery. This information is crucial for healthcare providers, as it sheds light on potential risks and outcomes of rTKA, allowing for improved patient management and surgical decision-making. III.

Influence of build orientation and support structure on additive manufacturing of human knee replacements: a computational study.

Developing patient-specific implants has an increasing interest in the application of emerging additive manufacturing (AM) technologies. On the other hand, despite advances in total knee replacement (TKR), studies suggest that up to 20% of patients with elective TKR are dissatisfied with the outcome. By creating 3D objects from digital models, AM enables the production of patient-specific implants with complex geometries, such as those required for knee replacements. Previous studies have highlighted concerns regarding the risk of residual stresses and shape distortions in AM parts, which could lead to structural failure or other complications. This article presents a computational framework that uses CT images to create patient-specific finite element models for optimizing AM knee replacements. The workflow includes image processing in the open-source software 3DSlicer and MeshLab and AM process simulations in the commercial platform 3DEXPERIENCE. The approach is demonstrated on a distal femur replacement for a 50-year-old male patient from the open-access Natural Knee Data. The results show that build orientations have a significant impact on both shape distortions and residual stresses. Support structures have a marginal effect on residual stresses but strongly influence shape distortions, whereas conical support exhibits a maximum distortion of 18.5 mm. Future research can explore how these factors affect the functionality of AM knee replacements under in-service loading.

Native knee kinematics are reproduced during the golf swing after total knee arthroplasty apart from rotation: A case control study of hip and knee kinematics of patients returning to golf compared to match controls

ObjectivesGolf is a popular sport in older adults and this same population has an increasing prevalence of osteoarthritis affecting major joints such as the knee. To the authors’ knowledge, the effect of Total Knee Arthroplasty (TKA) on the movements in the golf swing has not been extensively investigated despite the large prevalence of golfers who have undergone TKA. We aimed to determine lower limb joint kinematics during the golf swing and whether these are influenced following TKA. MethodsA case- control study was undertaken with ten right-handed golfers who had undergone TKA (cruciate-retaining single radius implant) and five matched golfers with native knees. Each golfer performed five swings with a driver whilst being recorded at 200 ​Hz by a ten-camera motion capture system. Knee and hip three-dimensional joint angles (JA) and joint angular velocities (JAV) were calculated and statistically compared between the groups at six swing events. ResultsThe left knee demonstrated large effect sizes for lower external rotation during take away, mid (p ​= ​0.01) and top of backswing in the TKA group. In contrast, the right knee demonstrated large effect sizes for lower external rotation in the TKA group during the downswing, contact and follow-through phases. There were no differences in knee flexion/extension, ab/adduction, or JAV between the groups. Both hips demonstrated statistically significantly (p ​= ​0.02 for left and p ​= ​0.04 for right) lower flexion in the TKA group during the takeaway swing event, and lower internal rotation in the backswing and greater external rotation in the downswing of the right hip. ConclusionNormal knee kinematics were observed during the golf swing following TKA, with the exception of reduced external rotation in the left knee during the backswing and the right during the down swing. The differences demonstrated in the hip motion indicate that they may make compensatory movements to adjust to the reduced external rotation demonstrated in the knee. Level of EvidenceIV.

Concomitant Anatomic PCL and FCL Reconstructions With Partial Lateral Meniscectomy

Background: Fibular collateral ligament (FCL) injuries commonly present in a multiligament knee injury pattern. These injuries are associated with significant instability leading to altered tibiofemoral biomechanics and therefore require surgical intervention. Similarly, grade 3 posterior cruciate ligament (PCL) injuries may disrupt normal tibiofemoral and patellofemoral biomechanics and increase the risk of secondary osteoarthritis. Therefore, concomitant reconstruction of the FCL and PCL should be performed to decrease knee laxity and optimize functional outcomes. Indications: Early operative treatment is indicated for patients with combined grade 3 FCL injuries and complete PCL tears. Contraindications to this procedure include patients who have significant osteoarthritis, open knee dislocations, or medical comorbidities making them unfit for surgery. Technique Description: The fundamental idea behind this technique is a stepwise treatment starting with open aspects of the procedure and followed by arthroscopic work. The technique is initiated with a lateral approach, common peroneal neurolysis, fibular and femoral FCL reconstruction tunnel preparation, and a gracilis or semitendinosus tendon autograft harvest. After that, focus shifts to intra-articular work such as associated meniscal assessment and treatment, PCL femoral and tibial tunnel preparation, graft passage, and PCL femoral tunnel fixation. Final graft fixation order is as follows: anterolateral bundle of PCL, posteromedial bundle of PCL, and finally FCL. Results: Multiple studies have reported that an anatomic FCL reconstruction in the setting of multiligament injury results in improved patient outcomes. In a prospective study of 20 patients, LaPrade et al reported −0.4 mm difference in side-to-side lateral compartment gapping and significant postoperative improvement of symptom and functional scores at a minimum 2 year postoperative follow-up after anatomic reconstruction of the FCL. Similarly, Moulton et al reported significant improvement in the average Western Ontario and Lysholm scores at 2.7 years follow-up. LaPrade et al also reported significant improvement in function and objective outcome scores at 3 years’ follow-up from anatomic double-bundle PCL reconstruction. Discussion: Anatomic FCL and PCL reconstructions successfully restore near native knee objective stability and provide superior clinical outcomes when compared to nonanatomic-based FCL reconstructions that continue to be performed. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Effect of self-lubricating carbon materials on the tribological performance of ultra-high molecular weight polyethylene

For over five decades, ultra-high molecular weight polyethylene (UHMWPE) has been the standard material for total knee replacements (TKR). Zero wear of the UHMWPE would be ideal; however, due to the natural knee movements, wear damage to the UHMWPE articulating surface is inevitable. The generated wear debris results in joint mechanical instability, reduced joint mobility, increased pain, and implant loosening. Because of these issues, the research on the materials in TKRs has increased their survival rate for up to 20 years; however, in younger patients, the durability of the UHMWPE component decreases due to increased physical activity. Hence there is a constant need for highly wear-resistant tribological pairs for TKRs. Carbon-based materials have an excellent balance between lubricating and mechanical properties and have shown great promise in tribological applications. This study used self-lubricating cubic titanium carbide (c-TiC) and multiwalled carbon nanotubes (MWCNTs) to improve the UHMWPE wear resistance further. The combination of carbon-based materials decreased the material loss by about 41.7 % compared to the UHMWPE vs. bare steel ball tribological pair. The improvement, attributed to the c-TiC self-lubricating coating surface, is close to 5 %. Cold flow and burnishing were the predominant wear mechanisms observed in all the systems; more subtle wear processes were detected for the sliding couple with c-TiC self-lubricating coating. Meanwhile, polymer delamination and micrometer-sized debris formation were the main wear mechanisms in the UHMWPE-MWCNT vs. bare steel ball system. The adhesion work obtained from the electronic structure calculations shows a more significant interfacial interaction of the CNTs on the c-TiC surface. This interaction can be associated with the layer formation that protects the surface from wear and friction.

Effect of Surgical Technique, Implant Design, and Time of Examination on Contact Kinematics: A Study of Bicruciate-Stabilized and Posterior-Stabilized Total Knee Arthroplasty

BackgroundBicruciate-stabilized (BCS) total knee arthroplasty (TKA) designs attempt to approximate natural knee mechanics. Multiple surgical techniques, including gap balancing (GB) and measured resection (MR), have been developed to provide optimal implant positioning and soft-tissue balance. The goal of this study was to determine the effect of surgical technique on BCS TKA contact kinematics. Secondary goals included investigating the change of kinematics over time and comparing BCS TKA kinematics to a posterior-stabilized (PS) design. MethodsThe study included the BCS-GB, BCS-MR, and PS-MR groups. The BCS-GB and BCS-MR groups underwent weight-bearing radiostereometric analysis for multiple knee flexion angles at 3 months and 1 year postoperatively, whereas the PS-MR group was imaged at 1 year postoperatively. The medial and lateral contact kinematics were determined from implant poses. ResultsThere were no differences in BCS TKA kinematics between the GB and MR techniques. There were differences in the mid-flexion ranges when comparing the 3-month and 1-year kinematics of the BCS design; however, they were less than 1.5 mm. Differences existed between the kinematics of the BCS and PS designs at all flexion angles for the medial condyle (P < .0006) and at 0° of flexion on the lateral condyle (P < .0001). ConclusionsContact kinematics for a BCS design were similar for both surgical techniques, suggesting both are appropriate for this design. Small, likely clinically insignificant differences were found between 3-month and 1-year kinematics. The BCS TKA kinematics differed from the PS design; however, it is unclear whether these differences improve clinical outcomes.

High three-dimensional accuracy of component placement and lower limb alignment using a robotic arm-assisted system and gap-balancing instrument in total knee arthroplasty.

It was hypothesized that robotic arm-assisted total knee arthroplasty (RA-TKA) using additionally a gap-balancing instrumentation will show high accuracy in executing the planning in femoral and tibial component placement throughout the range of knee motion (ROM) during TKA surgery. Prospectively collected data were analysed for patients undergoing RA-TKA. A cruciate retaining cemented design was implanted using the MAKO® robotic system. Lower limb alignment at 0°, 30°, 45°, 60° and 90° of flexion was recorded at the beginning of surgery and finally after implantation of the components. A ligament tensioner was inserted after tibial precut to measure the extension and flexion gap, and final component placement was planned based on 3D CT images. Femoral and tibial component placement was measured in all three planes. A total of 104 patients were included (mean age 69.4 ± 9 years; 44 male, 60 female). The difference in component placement after planning and final implantation showed less valgus of 0.7° ± 1.4° (p < 0.001), less external rotation of 0.6° ± 1.9° (p = 0.001) and less flexion of 0.9° ± 1.8° (p < 0.001) for the femoral component. The tibial component was placed in more varus of 0.2° ± 0.9° (p = 0.056) and more posterior slope of 0.5° ± 0.9° (p < 0.001). The lower limb alignment in extension was 4.4° ± 5.2° of varus of the native knee and changed to 1.2° ± 1.9° of varus after TKA (p < 0.01). Robotic-assisted TKA helps to achieve the target of alignment and component placement very close to the planning. It allows optimal component placement of off-the-shelf implants respecting patient's specific anatomy. Level II.