Higher Degrees Of Knee Flexion Research Articles

Combined Medial Patellofemoral Ligament and Medial Patellotibial Ligament Reconstruction for Recurrent Lateral Patellar Dislocation in Flexion

Recurrent lateral patellar dislocation can be a challenging entity to manage. It results from an imbalance between the restraints to lateralization of the patella and the forces applied to the patella within the biomechanical environment of the knee. The medial patellofemoral ligament has been recognized as the most important static soft-tissue restraint. However, the medial patellotibial ligament and medial patellomeniscal ligament are important for patellar stability at higher degrees of knee flexion. Lateral patellar dislocation in flexion poses a particularly challenging clinical entity with a combination of unique characteristics that need to be addressed to achieve optimal patellar tracking and stability. In this technical note, we describe a combined medial patellofemoral ligament and medial patellotibial ligament reconstruction technique to address lateral patellar dislocation in flexion.

Periarticular Injection of Ketorolac Augmenting Intravenous Administration of Ketorolac for Postoperative Pain Control: A Randomized Controlled Trial in Simultaneous Bilateral Total Knee Arthroplasty.

Adequate postoperative pain control with minimal side effects is necessary for patients undergoing total knee arthroplasty (TKA). Ketorolac is a frequently used nonsteroidal anti-inflammatory drug due to its excellent disposition in all administration routes; however, it possesses an "analgesic ceiling," which means that higher doses of the drug have no additional analgesic effect. Alternatively, increasing the local concentration of ketorolac via periarticular injection may provide additional pain relief to parenteral administration of ketorolac, but evidence demonstrating the benefits and safety of this approach is limited. Therefore, this study assesses whether local ketorolac injection could yield additional pain reduction to intravenous administration of ketorolac. A total of 54 patients who underwent simultaneous bilateral TKA were enrolled. Randomization was performed to determine whether 50 mg of bupivacaine plus 30 mg of ketorolac (ketorolac group), or only 50 mg bupivacaine (bupivacaine group) would be periarticularly injected into the first knee operated on (more painful), and then the contralateral knee would receive another mixture. Ketorolac (30 mg) was intravenously given every 8 hours for the first 48 hours. Visual analog scales (VASs) were used to assess pain, knee recovery function, and patients' preferred knee. Postoperative VAS pain scores in the ketorolac group were lower than those in the bupivacaine group 6 to 96 hours postoperatively and reached statistical significance 12 (4.25 ± 2.38 vs. 5.06 ± 2.48, respectively; p = 0.04) and 24 hours (4.22 ± 1.94 vs. 5.30 ± 2.12, respectively; p < 0.01) postoperatively. The ketorolac group had higher degrees of knee flexion and straight leg raise. No patient experienced adverse effects of ketorolac. On the day of discharge, 61.11% of the patients favored the knee that received local ketorolac injection (p < 0.01). Adjunct local ketorolac injection to systemic administration is well tolerated and may improve its analgesic effect as determined by the patients' perception.

The Presence of Patellar Apprehension in Higher Degrees of Flexion Identifies Patients with Patella Alta and or Severe Trochlear Dysplasia

Objectives:Recurrent patellar instability is frequently treated surgically with reconstruction of the medial patellofemoral ligament (MPFL). Patients with significant patella alta, trochlear dysplasia, and/or an elevated tibial tubercle-trochlear groove (TT-TG) distance may benefit from a concurrent bony procedure such as a tibial tubercle osteotomy or trochleoplasty. The indications to include such procedures are traditionally based on imaging criteria, but remain controversial. Patellar apprehension is common in patients with patellar instability but typically resolves in higher degrees of knee flexion. We hypothesis that the persistence of patellar apprehension at greater than 60 degrees of knee flexion is associated with patella alta, increased TT-TG distance, and trochlear dysplasia.Methods:Seventy-six patients with recurrent patellar instability were prospectively identified in a sports medicine clinic. Patellar apprehension was evaluated in each patient. Apprehension was defined as the patient reporting that the patella felt unstable to lateral patellar translation. Apprehension was first assessed at full knee extension and repeated assessed as the knee was flexed in 10 degrees intervals as measured with a goniometer. The degree of flexion at which patellar apprehension disappeared was recorded. Plain films and MRI were obtained in all patients. Patellar height was assessed with the Caton-Deschamps (CD) index and trochlear morphology was assessed through measurement of the sulcus angle and depth on MRI and classification with the Dejour classification system. Imaging measurements of patients in which apprehension resolved by 60 degrees of knee flexion were compared with measures for those with apprehension that persisted deeper into flexion.Results:Apprehension resolved by 60 degrees of flexion in 55 patients and persisted into deeper flexion in 21 patients. The patients with delayed resolution of apprehension demonstrated a higher CD Index, elevated TT-TG distance, increased higher sulcus angle, decreased trochlear depth, and a higher incidence of Dejour B, C, or D dysplasia (all p < 0.05, Table 1). Of the 21 patients with delayed resolution of apprehension, 18 had either Dejour B, C, or D dysplasia or a Caton-Deschamps Index of at least 1.3. Delayed resolution of apprehension was present in 11 of the 16 patients with Dejour B, C, or D dysplasia.Conclusion:The presence of patellar apprehension in higher degrees of knee flexion is associated with patella alta, increased TT-TG distance, and more severe trochlear dysplasia. Further work is needed to evaluate utility of this exam finding to inform surgical decision-making in this population.

Identifying Patients With Patella Alta and/or Severe Trochlear Dysplasia Through the Presence of Patellar Apprehension in Higher Degrees of Flexion.

Background:Recurrent patellar instability is frequently treated surgically with reconstruction of the medial patellofemoral ligament (MPFL). Patients with significant patella alta, trochlear dysplasia, and/or an elevated tibial tubercle–trochlear groove (TT-TG) distance may benefit from a concurrent bony procedure such as tibial tubercle osteotomy or trochleoplasty. The indications to perform such procedures are traditionally based on imaging criteria but remain controversial. Patellar apprehension is common in patients with patellar instability but typically resolves in higher degrees of knee flexion.Hypothesis:The persistence of patellar apprehension at greater than 60° of knee flexion is associated with patella alta, an increased TT-TG distance, and trochlear dysplasia.Study Design:Cross-sectional study; Level of evidence, 3.Methods:A total of 76 patients with recurrent patellar instability were prospectively identified in a sports medicine clinic. Patellar apprehension was evaluated in each patient. Apprehension was defined as the patient reporting that the patella felt unstable to lateral patellar translation. Apprehension was first assessed at full knee extension and repeatedly assessed as the knee was flexed in 10° intervals, as measured using a goniometer. The degree of flexion at which patellar apprehension disappeared was recorded. Plain radiographs and magnetic resonance imaging (MRI) scans were obtained for all patients. Patellar height was assessed with the Caton-Deschamps (CD) index, and trochlear morphology was assessed through measurements of the sulcus angle and depth on MRI and classified using the Dejour classification system. Imaging measurements of patients in whom apprehension resolved by 60° of knee flexion were compared with measurements for those with apprehension that persisted deeper into flexion.Results:Apprehension resolved by 60° of flexion in 56 patients and persisted into deeper flexion in 20 patients. The patients with a delayed resolution of apprehension demonstrated a higher CD index; elevated TT-TG distance; increased sulcus angle; decreased sulcus depth; and higher incidence of Dejour type B, C, or D dysplasia (all P < .05). Of the 20 patients with a delayed resolution of apprehension, 18 had either Dejour type B, C, or D dysplasia or a CD index of at least 1.30. A delayed resolution of apprehension was present in 11 of the 16 patients with Dejour type B, C, or D dysplasia.Conclusion:Overall, 90% of patients with significant patella alta and the majority of patients with high-grade trochlear dysplasia demonstrated patellar apprehension that persisted beyond 60° of knee flexion. Additionally, 90% of patients with persistent apprehension had significant patella alta and/or trochlear dysplasia. Further work is needed to evaluate the utility of these findings to inform surgical decision-making in this population.

Anatomy and Biomechanics of the Posterior Cruciate Ligament and Their Surgical Implications.

Knowledge and understanding of the complex anatomy and biomechanical function of the native posterior cruciate ligament (PCL) is vitally important when evaluating PCL injury and possible reconstruction. The PCL has important relationships with the anterior cruciate ligament, menisci, tibial spines, ligament of Humphrey, ligament of Wrisberg, and the posterior neurovascular structures. Through various experimental designs, the biomechanical role of the PCL has been elucidated. The PCL has its most well-defined role as a primary restraint/stabilizer to posterior stress and it seems this role is greatest at higher degrees of knee flexion. The natural history of high-grade deficiency leads to increased contact pressures and degeneration of both the medial and patellofemoral compartments. There is still considerable debate regarding whether high-level athletes can return to sport at the same level with conservative treatment of a high-grade PCL tear, and whether greater laxity in the knee correlates with decreased subjective and objective outcomes. Poor surgical outcomes after PCL reconstruction have been attributed to many factors, the most common of which include: additional intra-articular pathology, poor fixation methods, insufficient knowledge of PCL anatomy, improper tunnel placement, and poor surgical candidates.

Rehabilitation following meniscal repair: a systematic review

ObjectiveTo review existing biomechanical and clinical evidence regarding postoperative weight-bearing and range of motion restrictions for patients following meniscal repair surgery.Methods and data sourcesFollowing the Preferred Reporting Items for Systematic...

Patients with total knee arthroplasty do not use all of their available range of knee flexion during functional activities

BackgroundRecent research designed to improve outcome from total knee arthroplasty has included focus on strategies that increase the range of post-operative knee flexion. Patients with knee arthroplasty can now expect >100° of knee flexion following surgery, but it is not clear whether this improved range of motion facilitates outcome or whether patients take advantage of this range when completing daily functional activities. The aim of this study was to investigate the knee flexion angles used during daily functional activities that specifically required high degrees of knee flexion. It was hypothesised that patients with greater range of passive knee flexion would achieve higher degrees of knee flexion during functional activities. MethodsMotion analysis was used to assess the maximum knee flexion of 40 patients with total knee arthroplasty and 40 control participants as they performed maximum flexion squatting and lunging activities. FindingsPatients with knee arthroplasty used between 80.8 and 91.4° of knee flexion to complete these activities, which was 20 to 30% less than that used by the control participants. Patients with greater ranges of passive knee flexion had greater maximum knee flexion during functional activities. However, they used only between 68% and 77% of their full passive range when lunging and squatting. InterpretationThe development of rehabilitation strategies that aim to increase weightbearing knee flexion capacity may be warranted to improve functional performance following total knee arthroplasty.

Anatomy and Biomechanics of the Posterior Cruciate Ligament and Posterolateral Corner

The knowledge and understanding of the anatomy and biomechanical function of the posterior cruciate ligament (PCL) and posterolateral corner (PLC) of the knee is vitally important when evaluating injury and considering reconstruction. The PCL and the PLC both have important roles to play in the stability of the knee. Through numerous experimental designs, the biomechanical roles of the PCL and PLC have been clarified. The PCL’s most well-defined role is as a primary restraint and stabilizer to posterior stress. It appears that this role is greatest at higher degrees of knee flexion. The natural history of a PCL deficiency leads to increased contact pressures and degeneration of both the medial and patellofemoral compartments. The PLC is a restraint to posterior translation, posterolateral rotation, external rotation, and varus loads. It is important to recognize a PLC injury before cruciate ligament reconstruction, as a failure to diagnose may lead to subsequent graft rupture. Poor surgical outcomes after PCL reconstruction have been attributed to many factors, the most common of which include the following: additional intra-articular pathology, poor fixation methods, insufficient knowledge of PCL or PLC anatomy leading to improper tunnel placement, and poor surgical candidates. In this article, we attempt to provide a framework for understanding the anatomy and biomechanics of the PCL and PLC and their surgical implications.

Changes of Rheological Properties During Various Degrees of Knee Flexion after Meniscectomy

Aim of this article is to find out if there is any difference in rheological properties in various degrees of flexion in the knee with meniscal tear and compare the results with measurement after physical activity. Experimental measurements were done by using the method of biorheometry which detects the passive resistance of the knee in movement from flexion to extension. We found changes of rheological properties in higher degrees of knee flexion with typical rising followed by fall of biorheogram around flexion of 80°. They were more remarkable after physical activity. Changes of rheological properties were more expressive in patients who have undergone meniscectomy a few years ago than changes in patients with recent meniscectomy.

Anterior Cruciate Ligament Graft Isometry is Affected by the Orientation of the Femoral Tunnel.

The purpose of this study was to compare anterior cruciate ligament (ACL) graft length and tension throughout knee range of motion with transtibial, anteromedial (AM) portal, and all-epiphyseal drilling techniques with suspensory and apical femoral fixation. The three different femoral tunnel drilling techniques using the same intra-articular starting point within the center of the femoral footprint were performed on fresh-frozen cadaveric specimens. All groups underwent standard tibial drilling in the center of the ACL tibial footprint. FiberWire (Arthrex Inc., Naples, FL) was used to simulate anatomic single bundle reconstructions. Changes in graft length and tension were measured at knee flexion angles of 0, 30, 60, 90, 120, and 135 degrees. Graft length and tension decreased from 0 through 60 degrees and subsequently increased from 90 to 135 degrees for all groups. The transtibial, AM portal suspensory, and apical fixation groups were similar. However, the all-epiphyseal tunnel with suspensory fixation had a significantly increased change in length (90, 120, and 135 degrees) and tension (120 and 135 degrees). Transtibial and AM portal suspensory fixation and apical fixation demonstrate similar changes in length and tension throughout knee range of motion. The all-epiphyseal tunnel with suspensory fixation was associated with greater length and tension changes at higher degrees of knee flexion. All techniques demonstrated decreased graft length and tension with knee flexion to 60 degrees after which they increased with further knee flexion. ACL graft length and tension change throughout knee range of motion and also depend on femoral tunnel orientation and fixation type. The use of an all-epiphyseal tunnel with suspensory fixation should be studied further for evidence of graft elongation.

Quadriceps force after TKA with femoral single radius

Background and purpose New implant designs have incorporated a single radius instead of a multiple radius to the femoral component in order to improve the mechanical function after TKA. We investigated the amount of quadriceps force required to extend the knee during an isokinetic extension cycle of different total knee designs, focusing on the radius of the femoral component (single vs. multiple).Methods Human knee specimens (n = 12, median patient age 68 (63–70) years) were tested in a kinematic knee-simulating machine untreated and after implantation of 2 types of knee prosthesis systems, one with a single femoral radius design and one with a multiple femoral radius design. During the test cycle, a hydraulic cylinder, which simulated the quadriceps muscle, applied sufficient force to the quadriceps tendon to produce a constant extension moment of 31 Nm. The quadriceps extension force was measured from 120° to full knee extension.Results The shape of the quadriceps force curve was typically sinusoidal before and after TKA, reaching a maximum value of 1,493 N at 110°. With the single femoral radius design, quadriceps force was similar to that of the normal knee: 1,509 N at 110° flexion (p = 0.4). In contrast, the multiple femoral radius design showed an increase in quadriceps extension force relative to the normal knee, with a maximum of 1,721 N at 90° flexion (p = 0.03).Interpretation The single femoral radius design showed lower maximum extension forces than the multiple femoral radius design. In addition, with the single femoral radius design maximum quadriceps force needed to extend a constant extension force shifted to higher degrees of knee flexion, representing a more physiological quadriceps force pattern, which could have a positive effect on knee function after TKA.

Improved Clinical Outcomes After High-Flexion Total Knee Arthroplasty: A 5-Year Follow-Up Study

The purpose of this study was to determine if high-flexion total knee arthroplasty resulted in improved outcomes compared with conventional total knee arthroplasty. This was a prospective, double-blind, randomized controlled trial involving 76 patients over 5 years. We compared the postoperative flexion range, Knee Society scores, Oxford knee scores, and SF-36 scores between 2 groups. The high-flexion group was able to achieve a significant sustainable increase in postoperative knee flexion angle; and this correlated to a significant improvement in the General Health, Vitality, and Physical Functioning scales of SF-36 at 5 years postoperatively. Our results signify that high-flexion total knee arthroplasty has additional benefits to the quality of life in patients who require higher degrees of knee flexion in their activities of daily living.

Retropatellar Technique for Intramedullary Nailing of Proximal Tibia Fractures: A Cadaveric Assessment

To investigate if the radiographically correct and anatomically safe starting point and the appropriate sagittal plane vector could be obtained using a retropatellar technique for proximal tibia fractures treated with an intramedullary device. We performed a cadaveric and radiographic study utilizing 16 limbs. We performed a retropatellar approach via longitudinal quadriceps split, passed a specialized trocar through the patellofemoral joint and onto the superior aspect of the tibia, and inserted Kirschner wires into the anatomic safe zone of the tibial plateau at 0, 10, 20, 30, 40, and 50 degrees of knee flexion utilizing biplanar fluoroscopy. We recorded knee flexion with a goniometer and the entrance vector of the Kirschner wire in relation to the anterior tibial cortex. University-affiliated cadaver and anatomy laboratory. There was a progressive increase in the ability to obtain the correct anatomical start site from 1 of 16 (6.25%) at full extension to 12 of 16 (75%) at 50 degrees of knee flexion (P = 0.00098). A statistically significant decrease in the average sagittal plane entrance vector in relation to the anterior tibial cortex was found from 23.1 degrees at full extension to -0.41 degrees at 50 degrees of knee flexion (P < 0.0001). The retropatellar technique allows the radiographically defined correct start site to be localized, particularly at higher degrees of knee flexion. More favorable intramedullary nail insertion angles were possible with the retropatellar technique, particularly with knee flexion angles greater than 20 degrees. The retropatellar technique demands further investigations to further delineate its advantages, limitations, and possible risks to local anatomy.

Potential Risks of Femoral Tunnel Drilling Through the Far Anteromedial Portal: A Cadaveric Study

The purpose of this study was to estimate the potential risks when drilling femoral tunnels through the far anteromedial portal in double-bundle anterior cruciate ligament reconstruction in cadaveric knees. Ten cadaveric knees were used. We drilled the anteromedial bundle (AMB) and posterolateral bundle (PLB) through the far anteromedial portal at 3 different knee flexion angles: 70 degrees, 90 degrees, and 110 degrees. We measured the shortest distance to the common peroneal nerve and the posterior articular cartilage of the lateral femoral condyle and the femoral tunnel length. At 70 degrees, the distance to the nerve was less than 10 mm in 7 AMB cases and in 9 PLB cases, and the distance to the cartilage was less than 10 mm in all the AMB and PLB cases. At 90 degrees, the distance to the nerve was less than 10 mm in 1 AMB and 5 PLBs, and the distance to the cartilage was less than 10 mm in 2 AMBs and all the PLBs. On the other hand, at 110 degrees , the distance to the nerve was greater than 10 mm in all the AMBs and PLBs, and the distance to the cartilage did not exceed 10 mm in just 2 of the PLBs. In our cadaveric study we found that the low knee flexion angles when drilling femoral tunnels through the far anteromedial portal might have the potential risks of damage to the common peroneal nerve and the posterior articular cartilage, and the risks would be decreased at higher degrees of knee flexion. However, we found there was a 20% risk of damage to the cartilage while drilling the PLB at 110 degrees. High knee flexion angles are recommended to avoid damage to the nerve and the cartilage when drilling femoral tunnels through the far anteromedial portal in double-bundle anterior cruciate ligament reconstruction.

A methodology for the pre-clinical evaluation of patellar implants

A methodology for the alignment of patellar and femoral components in pre-clinical test of patellar components used in total knee arthroplasty is presented. The component alignment was based on kinematic degrees of freedom that should be considered to recreate clinically relevant patello-femoral contact patterns. A literature review of patellar kinematics revealed that patellar motion occurs in all six degrees of freedom. Retrieval studies reported that deformation was most prominent on the lateral aspect of the patellar component and in contact regions that occur at higher degrees of knee flexion. Based on this review, it was hypothesised that alignment of the patellar and femoral components should incorporate patellar flexion, proximal-distal translation, anterior-posterior translation and medial-lateral translation. The efficacy of the model was tested by evaluating its ability to create physiological contact patterns in patellar components used in total knee arthroplasty. Two types of components were tested: metal-backed dome and all-polyethylene sombrero-shaped of which the dome-shaped components have a higher reported incidence of failure. The component alignment method resulted in higher contact areas in the sombrero-shaped components than the dome-shaped. Contact patterns of both components were compared to contact patterns reported in the literature for natural and implanted patellae and compared favourably.

Optimizing flexion after total knee arthroplasty: advances in prosthetic design.

The clinical results with most modern total knee arthroplasty (TKA) designs are highly satisfactory regarding pain relief and improving walking ability. However, one problem that has not been addressed fully by most current designs is the ability to consistently achieve flexion greater than 120 degrees. Although the human knee is capable of flexion of more than 150 degrees, an analysis of the results of contemporary TKA reveals that on average, patients rarely flex beyond 120 degrees. Key factors influencing range of flexion after TKA include preoperative knee motion, surgical technique, prosthetic design, and rehabilitation. The success of any total knee system may in part be linked to its ability to optimally restore normal kinematic function. Some arthroplasty designs currently are available that incorporate modifications aimed at improving range of flexion, but limited data currently are available on their function and potential advantages. Currently, an in vitro experimental model incorporating robotics is being used to investigate the kinematics of the native knee and various TKA designs at flexion angles beyond 120 degrees. This robotic model in conjunction with clinical studies may provide an understanding of the limitations of contemporary knee designs regarding achieving higher degrees of knee flexion. This may lead to the refinement of existing designs and development of newer prostheses that may enhance the range of flexion that is achievable after TKA.