Normal Knee Joint Kinematics Research Articles

Implantation of Novel Meniscus Scaffold for Irreparable Meniscal Tear

Partial meniscectomy, which is generally used for the treatment of meniscal tears, can lead to knee joint osteoarthritis. To prevent this important complication, attempting to restore normal knee joint kinematics and biomechanical forces after partial meniscectomy is essential. Implantation of a meniscal scaffold can be useful in this regard, improving the function of the meniscus on knee joint biomechanics after partial meniscectomy. Use of meniscal scaffolds would have specific clinical merit for young patients who are at highest for developing knee joint osteoarthritis over time. Herein, we describe our novel bioabsorbable meniscal scaffold, fabricated with polyglycolic acid coated with polylactic acid/caprolactone, used after partial meniscectomy for degenerative and irreparable meniscal tears. The method of implantation of the scaffold will have a determinant effect on clinical outcomes. As the implementation technique by arthroscopy will be influenced by the stiffness and strength of the scaffold implant used, we provide a detailed description of our implantation technique, including a description of the pitfalls to consider in order to improve clinical outcomes.

Short-Term Functional Outcome and Satisfaction Rate of Unicompartmental Knee Arthroplasty in Indian Population: A Retrospective Study.

Introduction: Unicompartmental knee arthroplasty (UKA) is a procedure used to treat isolated medial or lateral compartmental osteoarthritis of the knee joint. This procedure involves retention of cruciate ligaments which leads to better functional outcome due to preservation of normal kinematics of the knee joint. In the Indian population, due to requirement of squatting and cross leg sitting habits, knee with more range of movement and with good kinematics is a required feature. The study aims to observe the functional outcome, mortality, revision rate, length of hospital stay and satisfaction rate in two-year postoperative patients in a tertiary health care centre.Methods: A total of 17 knees of 15 patients were recruited for the study after applying strict inclusion and exclusion criteria. These patients were operated during the period from March 2015 to March 2018. Ten female patients (67%) and five males (33%) were included. The average age was 61 years. All operations were performed by a single surgeon, with a similar implant from a single company. Similar protocol was used both for surgical technique (minimal invasive) and postoperative rehabilitation for all the patients.Results: The functional outcome in the form of Oxford Knee Score (OKS) and Euro-Quol (EQ-5D) scores improved significantly in all the patients at one year postoperatively, and the improvement remained significant for two years. Satisfaction rate was 91.7% (SD-12.8) at two years. Except for one patient (5.8%), all patients were able to cross leg and squat easily. At the end of two years, the overall survival rate of the implant was found to be 94.1%.Conclusion: The unicondylar arthroplasty provides excellent satisfaction to the appropriately selected patients with good survivorship of implant. It can be a surgery of choice for Indian population as it restores normal kinematics of knee joint and allows the patient to cross leg and squat with a more range of movement.

Analysis of in-vivo articular cartilage contact surface of the knee during a step-up motion

BackgroundNumerous studies have reported on the tibiofemoral articular cartilage contact kinematics, however, no data has been reported on the articular cartilage geometry at the contact area. This study investigated the in-vivo tibiofemoral articular cartilage contact biomechanics during a dynamic step-up motion. MethodsTen healthy subjects were imaged using a validated magnetic resonance and dual fluoroscopic imaging technique during a step-up motion. Three-dimensional bone and cartilage models were constructed from the magnetic resonance images. The cartilage contact along the motion path was analyzed, including cartilage contact location and the cartilage surface geometry at the contact area. FindingsThe cartilage contact excursions were similar in anteroposterior and mediolateral directions in the medial and lateral compartments of the tibia plateau (P>0.05). Both medial and lateral compartments were under convex (femur) to convex (tibia) contact in the sagittal plane, and under convex (femur) to concave (tibia) contact in the coronal plane. The medial tibial articular contact radius was larger than the lateral side in the sagittal plane along the motion path (P<0.001). InterpretationsThese data revealed that both the medial and lateral compartments of the knee experienced convex (femur) to convex (tibia) contact in sagittal plane (or anteroposterior direction) during the dynamic step-up motion. These data could provide new insight into the in-vivo cartilage contact biomechanics research, and may provide guidelines for development of anatomical total knee arthroplasties that are aimed to reproduce normal knee joint kinematics.

Arthroscopic Primary Repair of Proximal Anterior Cruciate Ligament Tears

In a select group of patients with proximal anterior cruciate ligament (ACL) tears, primary repair can be a useful technique. Preservation of the native ACL may be advantageous for proprioceptive function and is thought to restore normal knee joint kinematics. The procedure is a less morbid and more conservative surgical approach to restore knee stability. Primary repair is preferably performed in the acute setting because of better healing capacity and tissue quality. We present the surgical technique of arthroscopic primary ACL repair with suture anchors in patients with proximal tears and excellent tissue quality.

Transtibial versus anteromedial portal technique in single-bundle anterior cruciate ligament reconstruction: A randomized controlled study with 5 years of follow-up

The purpose of our study is to compare the effectiveness of these two surgical techniques, the transtibial (TT) and the anteromedial (AM) technique, in restoring the normal knee joint kinematics after the arthroscopic ACL reconstruction made with hamstrings single-bundle graft. The study design is a controlled randomized study with 5 years of follow-up. Two hundred patients were sequentially enrolled, 100 patients in the TT and 100 in the AM group. All patients underwent clinical, instrumental and radiological study before and after surgery. The clinical evaluation included the 2000 IKDC subjective knee score, Lysholm knee score, Tegner activity scale, Lachman test, pivot shift test. Instrumental evaluation was made with KT-1000 arthrometer and gait analysis. Radiological evaluation was made on plain X-rays. The minimum follow-up is 5 years. More coronal obliquity of femoral tunnel was gained with AM technique. No between group differences were seen for what regards stability and return to sports activity.

The Coupled Motion of the Femur and Patella During In Vivo Weightbearing Knee Flexion

The movement of the knee joint consists of a coupled motion between the tibiofemoral and patellofemoral articulations. This study measured the six degrees-of-freedom kinematics of the tibia, femur, and patella using dual-orthogonal fluoroscopy and magnetic resonance imaging. Ten normal knees from ten living subjects were investigated during weightbearing flexion from full extension to maximum flexion. The femoral and the patellar motions were measured relative to the tibia. The femur externally rotated by 12.9 deg and the patella tilted laterally by 16.3 deg during the full range of knee flexion. Knee flexion was strongly correlated with patellar flexion (R(2)=0.91), posterior femoral translation was strongly correlated to the posterior patellar translation (R(2)=0.87), and internal-external rotation of the femur was correlated to patellar tilt (R(2)=0.73) and medial-lateral patellar translation (R(2)=0.63). These data quantitatively indicate a kinematic coupling between the tibia, femur, and patella, and provide base line information on normal knee joint kinematics throughout the full range of weightbearing flexion. The data also suggest that the kinematic coupling of tibia, femur, and patella should be considered when investigating patellar pathologies and when developing surgical techniques to treat knee joint diseases.

The Meniscus in the Cruciate-Deficient Knee

Evidence clearly implicates meniscectomy as a primary factor in the premature development of OA of the knee joint. Although data demonstrate the ability of the menisci to transmit load, they do not contribute to the primary stability of the knee. In the absence of the ACL, the menisci have been shown to enhance the knee's stability in the AP, varus-valgus, and internal-external directions in vitro. Clinically, the argument that the menisci are important secondary stabilizers is less clear. The restraining capacity of the menisci to AP translation is much smaller than the forces the knee is subjected to in vivo during activities of daily living. Additionally, these forces can increase as much as threefold during strenuous athletics. It becomes apparent, on review of the literature, that the menisci clearly are not designed to participate as a significant restraining mechanism for the ACL-deficient knee. The incidence of acute meniscal tear is 52% and increases to 83% in the long run. It is important to realize that although the menisci contribute in part to the stability of the ACL-deficient knee, such a role places them at risk for injury. When meniscal lesions are noted in the ACL-deficient knee, it is important to bear in mind the patient's goals, including his or her willingness to have an ACL reconstructive procedure and desire to return to sports. Also, the tear's configuration and location dictate its the ability to heal. One final area of interest relates to the fate of an ACL reconstruction in the meniscus-deficient knee. Although the meniscus is not a participant in primary stability, the subtle alteration in knee joint kinematics may create unfavorable conditions for the ACL graft. It is possible that the menisci may provide some protection to an ACL-reconstructed knee by restoring normal knee joint kinematics. Such a situation may explain why some ACL reconstructions in the meniscectomized knee fail over time. Prosthetic meniscal substitution or allograft meniscal transplantation are techniques on the horizon and may prove useful in the future when the remaining meniscus cannot be repaired.