Changed gait pattern in patients with total knee arthroplasty but minimal influence of tibial insert design: gait analysis during level walking in 39 TKR patients and 18 healthy controls

INTRODUCTION: Previous radiostereometric studies have revealed abnormal anterior-posterior translation of the femur in patients operated with AMK (DePuy, Johnson and Johnson, Leeds, UK) total knee arthroplasty (TKA). Based on these observations, we hypothesized that patients with TKA have an abnormal gait pattern, and that there are differences in kinematics depending on the design of the tibial joint area. METHOD: We used a gait analysis system to evaluate the influence of joint area design on the kinematics of the hip and knee during level walking. 39 TKA patients (42 knees) and 18 healthy age-matched controls were studied. Patients with 5 degrees varus/valgus alignment or less were randomized to receive either a relatively flat or a concave tibial insert with retention of the posterior cruciate ligament. Patients who had more than 5 degrees varus-valgus alignment and/or extension defect of 10 degrees or more were randomized to receive the concave or a posterior-stabilized tibial component with resection of the posterior cruciate ligament. RESULTS: Patients with TKA tended to have less hip and knee extension and decreased knee and hip extension moment than controls. They also tended to walk more slowly. TKA altered the gait pattern, but choice of implant design had little influence. INTERPRETATION: In patients with a similar degree of degenerative joint disease and within the limits of the constraints offered by the prostheses under study, the choice of joint area constraint has little influence on the gait pattern.     

Changes in Knee Kinematics Reflect the Articular Geometry after Arthroplasty

We hypothesized changes in rotations and translations after TKA with a fixed-bearing anterior cruciate ligament (ACL)-sacrificing but posterior cruciate ligament (PCL)-retaining design with equal-sized, circular femoral condyles would reflect the changes of articular geometry. Using 8 cadaveric knees, we compared the kinematics of normal knees and TKA in a standardized navigated position with defined loads. The quadriceps was tensed and moments and drawer forces applied during knee flexion-extension while recording the kinematics with the navigation system. TKA caused loss of the screw-home; the flexed tibia remained at the externally rotated position of normal full knee extension with considerably increased external rotation from 63° to 11° extension. The range of internal-external rotation was shifted externally from 30° to 20° extension. There was a small tibial posterior translation from 40° to 90° flexion. The varus-valgus alignment and laxity did not change after TKA. Thus, navigated TKA provided good coronal plane alignment but still lost some aspects of physiologic motion. The loss of tibial screw-home was related to the symmetric femoral condyles, but the posterior translation in flexion was opposite the expected change after TKA with the PCL intact and the ACL excised. Thus, the data confirmed our hypothesis for rotations but not for translations. It is not known whether the standard navigated position provides the best match to physiologic kinematics. One or more of the authors (AAA, AMJB) have received funding by Stryker (Europe). Each author certifies that his or her institution has approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research, and that tissue specimens were obtained in accordance with the laws of France.     

The influence of component alignment on patellar kinematics in total knee arthroplasty

Background and purpose — Postoperative anterior knee pain is one of the most frequent complications after total knee arthroplasty (TKA). Changes in patellar kinematics after TKA relative to the preoperative arthritic knee are not well understood. We compared the patellar kinematics preoperatively with the kinematics after ligament-balanced navigated TKA.

Patients and methods — We measured patellar tracking before and after ligament-balanced TKA in 40 consecutive patients using computer navigation. Furthermore, the influences of different femoral and tibial component alignment on patellar kinematics were analyzed using generalized linear models.

Results — After TKA, the patellae shifted statistically significantly more laterally between 30° and 60°. The lateral tilt increased at 90° of flexion whereas the epicondylar distance decreased between 45° and 75° of flexion. Sagittal component alignment, but not rotational component alignment, had a significant influence on patellar kinematics.

Interpretation — There are major differences in patellar kinematics between the preoperative arthritic knee and the knee after TKA. Combined sagittal component alignment in particular appears to have a major effect on patellar kinematics. Surgeons should be especially aware of altering preoperative sagittal alignment until the possible clinical relevance has been investigated.     

Flat vs. concave tibial joint surface in total knee arthroplasty: Randomized evaluation of 39 cases using radiostereometry

40 patients with non-inflammatory arthrosis and minor preoperative deformity (/ 5°) were operated on with an AMK type (DePuy, Johnson & Johnson) total knee arthroplasty (TKA). The posterior cruciate ligament was retained. The patients were divided into those with a flat (terminology of the manufacturer: standard) or a concave (terminology of the manufacturer: constrained) polyethylene insert (20 in each group). Radiostereometric (RSA) examinations were done postoperatively and after 3, 12 and 24 months. The median absolute rotations of the tibial inserts varied between 0.12 and 0.24 (range 0.00-1.54) degrees, with no differences between the 2 groups. The median maximum totalpoint motions (flat/concave = 0.41/0.42 mm), the maximum subsidence or lift-off did not differ. The Hospital for Special Surgery knee score and the patients' opinion about the operation, based on their preoperative expectations, showed little, if any, differences. At 2 years, 10 of 20 patients with flat and 13 of 19 with concave inserts regarded their knee function as normal or almost so.     

Bi‐Cruciate Retaining Total Knee Arthroplasty Does Not Restore Native Tibiofemoral Articular Contact Kinematics During Gait

Bi‐cruciate retaining (BCR) total knee arthroplasty (TKA) design preserves both anterior and posterior cruciate ligaments with the potential to restore normal posterior femoral rollback and joint kinematics. Abnormal knee kinematics and “paradoxical” anterior femoral translation in conventional TKA designs have been suggested as potential causes of patient dissatisfaction. However, there is a paucity of data on the in vivo kinematics and articular contact behavior of BCR‐TKA. This study aimed to investigate in vivo kinematics, articular contact position, and pivot point location of the BCR‐TKA during gait. In vivo kinematics of 30 patients with unilateral BCR‐TKA during treadmill walking was determined using validated dual fluoroscopic imaging tracking technique. The BCR‐TKA exhibited less extension than the normal healthy knee between heel strike and 48% of gait cycle. Although the average external rotation trend observed for BCR TKA was similar to the normal healthy knee, the range of motion was not fully comparable. The lowest point of the medial condyle showed longer anteroposterior translation excursion than the lateral condyle, leading to a lateral‐pivoting pattern in 60% of BCR TKA patients during stance phase. BCR‐TKA demonstrated no statistical significant differences in anterior–posterior translation as well as varus rotation, when compared to normal healthy knees during the stance phase. However, sagittal plane motion and tibiofemoral articular contact characteristics including pivoting patterns were not fully restored in BCR TKA patients during gait, suggesting that BCR TKA does not restore native tibiofemoral articular contact kinematics. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1929–1937, 2019     

Influence of Increased Posterior Tibial Slope in Total Knee Arthroplasty on Knee Joint Biomechanics: A Computational Simulation Study

Background

The reconstructed posterior tibial slope (PTS) plays a significant role in restoring knee kinematics in cruciate-retaining-total knee arthroplasty (TKA). A few studies have reported the effect of the PTS on biomechanics.

Total knee replacement influences both knee and hip joint kinematics during stair climbing

A gait analysis system was used to evaluate the kinematics of the hip and knee during stair ascending and descending after operation with total knee replacement. Patients with 5° varus/valgus alignment or less were selected randomly to receive either a flat or a concave tibial component with retention of the posterior cruciate ligament. Patients who had more than 5° varus/valgus alignment and/or an extension defect of 10° or more were selected randomly to receive the concave or posterior-stabilized tibial component with resection of the posterior cruciate ligament. Twenty patients and 17 controls were studied 1–2 years after the operation. Patients had abnormal kinematics during stair ascending and descending. Both knee extension and flexion were reduced. Hip extension tended to decrease, and decreased hip extension moment was noted.

---

Résumé Un system danalyse de la marche a été utilisé pour évaluer la cinématique de la hanche et du genou pendant la montée et la descente descalier après prothèse totale du genou. Les malades avec 5° ou moins de varus/valgus ou moins ont été randomisés pour recevoir un composant tibial plat ou concave avec conservation du ligament croisé postérieur. Les malades qui avaient plus de 5° de varus/valgus et/ou un défaut dextension de 10° ou plus ont été randomisés pour recevoir un composant tibial concave ou un composant postéro-stabilisé avec résection du ligament croisé postérieur. Vingt et un malades et 17 contrôles ont été étudiés une à deux années après lopération. Les malades avaient une cinématique anormale pendant la montée et la descente lescalier. Lextension et flexion du genou étaient plus faibles. Lextension de la hanche avait tendance à diminuer et une augmentation du moment de flexion a été noté.

     

Knee joint kinematics, fixation and function related to joint area design in total knee arthroplasty

The aim was to study the influence of different designs of the joint area on tibial component fixation, kinematics and clinical outcome after a cemented total knee arthroplasty (TKA). The HSS score and a special questionnaire were used at the clinical examination. Conventional radiography was done to record the positioning of the implants and development of radiolucencies. The migration and inducible displacement were evaluated using radiostereometry (RSA). The kinematics of the knee during active extension was studied using dynamic RSA. In randomised and prospective studies 87 knees in 83 patients (28 male, 55 female, age 69, range 50-83) received an AMK (DePuy, Johnson & Johnson) TKA. The patients were divided into two groups. In group 1 the patients had varus/valgus deformities of < or = 5 degrees and the PCL was retained. The PCL was resected in group 2 where the patients had deformities exceeding 5 degrees and/or fixed flexion deformities of more than 10 degrees. In group 1 a flat (F, n = 20) or a concave (C, n = 20) design was implanted (study 3). In group 2 (study 4) the patients received a concave (n = 25) or a posterior-stabilised (PS, n = 22) tibial plateau. The migration of the tibial component, positioning of the prosthesis, development of radiolucencies and the clinical outcome was evaluated after 1 and 2 years. Twenty-two patients (11 F, 11 C) in group 1 (study 1) and 22 knees in 20 patients in group 2 (study 2, 11 C, 11 PS) were examined 1 year post-operatively to evaluate the kinematics of the knee. Eleven normals served as controls. During active extension of the knee the inducible displacements of the tibial component were recorded in 16 knees (15 patients). Based on successful RSA examinations 5 knees (4 F, 1 C) from group 1 and 11 knees (5 C, 6 PS) from group 2 were selected (study 5). Abnormal kinematics and especially increased AP translations compared to normals (p < 0.0005) were recorded in all designs. The concave design showed the widest AP-translations in both studies. The clinical outcome in terms of HSS score did not differ between the flat versus the concave designs in study 1 and between the concave versus the PS implants in study 2. Up to two years the migration of the tibial component and the development of radiolucent lines were of the same magnitude for the flat versus the concave inserts in study 3 and the concave versus the PS design in study 4. Also did the positioning of the implant and the fulfillment of the patients expectations on the surgery preoperatively not differ. The AMK prosthesis migrated at about the same amount as have been reported for similar designs. In study 5 all implants showed a correlation between some of the inducible displacements (anterior-posterior tilting and maximum total point motion) and the corresponding migration 0-2 years. The more the anterior tilt the more the migration in the same direction. If the PCL was sacrificed during the knee replacement the change into increased anterior tilt occurred earlier (i.e. at more degree of flexion) if a concave insert was used compared to the PS design. When the active extension reached 25 degrees there were more anterior tilt of the tibial component in the concave design (p = 0.001) and if the tibial plateau centre had a medial position (p < 0.0005). Compared with normal knees all prosthetic designs showed abnormal pattern of motion. The extent of this abnormality was influenced by the design of the joint area. A corresponding influence on the fixation of the tibial component could not be verified. The choice of joint area and recorded kinematics had no or small influence on the clinical results. Feelings of instability could to some extent be related to the kinematics of the knee joint.     

Functional analysis of cemented medial unicompartmental knee arthroplasty

Gait analysis was used to study patients who underwent cemented medial unicompartmental knee arthroplasty (UKA) for medial compartment degenerative knee disease. All had excellent clinical function of the operated knee, with minimal involvement of other joints. Ten patients met the inclusion criteria for this study. Gait findings from this study group, as well as those from a similar cohort of patients who had undergone total knee arthroplasty (TKA), were compared with those for a group of normal patients. A greater percentage of patients (7 of 10) following UKA maintained the normal biphasic flexion/extension moment pattern about the knee or demonstrated a quadriceps overuse pattern, when compared with similar groups following TKA. In addition, the adduction moment in patients following UKA was significantly larger than in patients following TKA. The postoperative limb alignment correlated with the peak adduction moment recorded during the patient's gait analysis. The postoperative alignment may explain the differences in the adduction moment between the UKA and TKA patients, as there tended to be residual varus in the UKA population. The results of this study imply that preservation of the anterior cruciate ligament during UKA allows patients to maintain normal quadriceps mechanics, and that residual varus alignment subjects a medial UKA to higher loads.     

Flat vs. concave tibial joint surface in total knee arthroplasty: randomized evaluation of 39 cases using radiostereometry

40 patients with non-inflammatory arthrosis and minor preoperative deformity (< or =5 degrees ) were operated on with an AMK type (DePuy, Johnson & Johnson) total knee arthroplasty (TKA). The posterior cruciate ligament was retained. The patients were divided into those with a flat (terminology of the manufacturer: standard) or a concave (terminology of the manufacturer: constrained) polyethylene insert (20 in each group). Radiostereometric (RSA) examinations were done postoperatively and after 3,12 and 24 months. The median absolute rotations of the tibial inserts varied between 0.12 and 0.24 (range 0.00-1.54) degrees, with no differences between the 2 groups. The median maximum total-point motions (flat/concave = 0.41/0.42 mm), the maximum subsidence or lift-off did not differ. The Hospital for Special Surgery knee score and the patients' opinion about the operation, based on their preoperative expectations, showed little, if any, differences. At 2 years, 10 of 20 patients with flat and 13 of 19 with concave inserts regarded their knee function as normal or almost so.     

Flat vs. concave tibial joint surface in total knee arthroplasty: Randomized evaluation of 39 cases using radiostereometry

40 patients with non-inflammatory arthrosis and minor preoperative deformity (/ 5°) were operated on with an AMK type (DePuy, Johnson & Johnson) total knee arthroplasty (TKA). The posterior cruciate ligament was retained. The patients were divided into those with a flat (terminology of the manufacturer: standard) or a concave (terminology of the manufacturer: constrained) polyethylene insert (20 in each group). Radiostereometric (RSA) examinations were done postoperatively and after 3, 12 and 24 months. The median absolute rotations of the tibial inserts varied between 0.12 and 0.24 (range 0.00-1.54) degrees, with no differences between the 2 groups. The median maximum totalpoint motions (flat/concave = 0.41/0.42 mm), the maximum subsidence or lift-off did not differ. The Hospital for Special Surgery knee score and the patients' opinion about the operation, based on their preoperative expectations, showed little, if any, differences. At 2 years, 10 of 20 patients with flat and 13 of 19 with concave inserts regarded their knee function as normal or almost so.     

Sagittal laxity after posterior cruciate ligament-retaining mobile-bearing total knee arthroplasty

Posterior cruciate ligament stretching after posterior cruciate ligament-retaining (CR) total knee arthroplasty (TKA) can lead to an increase in sagittal laxity, knee dysfunction, or accelerated damage to the tibial bearing surface. We conducted a prospective study on 74 consecutive mobile-bearing CR TKA to determine if knee laxity changed with time or if knees with large initial laxity experienced greater increases in laxity. Patients were studied with radiographic posterior and anterior drawer examinations at 3 and 23 months. Model-based shape-matching techniques were used to measure TKA kinematics. We found a 1-mm increase in posterior drawer. Knees with large postoperative drawers did not exhibit increased laxity at last follow-up. The use of a mobile-bearing CR TKA did not significantly modify the midterm knee sagittal laxity.     

In vivo kinematics of total knee arthroplasty: flat compared with concave tibial joint surface.

This study evaluated the influence of the geometric configuration of the tibial joint area on the kinematics of the knee. Twenty-two patients with noninflammatory arthritis and minor preoperative deformity were studied. They each received an AMK total knee replacement with retention of the posterior cruciate ligament. Eleven patients without any knee abnormalities were used as controls. The patients were stratified to either the flat (terminology of the manufacturer: standard) or concave (terminology of the manufacturer: constrained) polyethylene insert (n = 11 in each group). Knee kinematics were assessed 1 year after the operation by having the patient ascend a platform corresponding to an extension of the knee from 50 to 70 degrees of flexion. During this motion, two film-exchangers simultaneously exposed six to 13 pairs of serial stereoradiographs. The concave geometric configuration of the tibial insert resulted paradoxically in increased anterior-posterior translations compared with the flat insert but no significant change of rotations and translations in the other directions. Compared with normal knees, the most obvious abnormality was increased anterior-posterior translations (p < 0.004). At 50 degrees of flexion, the implants with the flat tibial polyethylene insert had displaced 2 times and the concave ones had displaced 2.5 times more posteriorly than the normal knees (p < or = 0.001). Less internal tibial rotation was also recorded in the flexed positions for both types of inserts compared with the normal knees (p < 0.02). Four knees in four patients, who reported symptoms of instability and abnormal knee function, showed significantly increased proximal displacement of the center of the tibial plateau in the flexed position. The findings suggest that current prosthetic designs and surgical technique do not restore normal knee kinematics and indicate that design improvements should rely on in vivo kinematic studies.     

Kinematics after tear in the anterior cruciate ligament: dynamic bilateral radiostereometric studies in 11 patients

We studied the kinematics of both knees using radiostereometry in 11 patients with unilateral injury of the anterior cruciate ligament and normal contralateral knee. Continuous radiostereometric exposures at a speed of 24 exposures a second were performed, when the patients ascended an 8 cm high platform. The tibial center was more dorsally displaced and the tibia more externally rotated on the injured side. This increasing external tibial rotation was associated with increased anterior displacement of the lateral femoral condyle. The latter also displayed less anterior-posterior translations during continuous extension. The anterior-posterior translation of the medial condyle was about the same as on the uninjured side. Changes in the kinematics of the knee joint due to rupture of the anterior cruciate ligament can result in an abnormal joint load, which may increase the risk of damage to the cartilage and the menisci.     

Kinematics after tear in the anterior cruciate ligament: Dynamic bilateral radiostereometric studies in 11 patients

We studied the kinematics of both knees using radiostereometry in 11 patients with unilateral injury of the anterior cruciate ligament and normal contralateral knee. Continuous radiostereometric exposures at a speed of 2-4 exposures a second were performed, when the patients ascended an 8 cm high platform. The tibial center was more dorsally displaced and the tibia more externally rotated on the injured side. This increasing external tibial rotation was associated with increased anterior displacement of the lateral femoral condyle. The latter also displayed less anterior-posterior translations during continuous extension. The anterior-posterior translation of the medial condyle was about the same as on the uninjured side. Changes in the kinematics of the knee joint due to rupture of the anterior cruciate ligament can result in an abnormal joint load, which may increase the risk of damage to the cartilage and the menisci.     

Kinematics after tear in the anterior cruciate ligament: Dynamic bilateral radiostereometric studies in 11 patients

We studied the kinematics of both knees using radiostereometry in 11 patients with unilateral injury of the anterior cruciate ligament and normal contralateral knee. Continuous radiostereometric exposures at a speed of 2-4 exposures a second were performed, when the patients ascended an 8 cm high platform. The tibial center was more dorsally displaced and the tibia more externally rotated on the injured side. This increasing external tibial rotation was associated with increased anterior displacement of the lateral femoral condyle. The latter also displayed less anterior-posterior translations during continuous extension. The anterior-posterior translation of the medial condyle was about the same as on the uninjured side. Changes in the kinematics of the knee joint due to rupture of the anterior cruciate ligament can result in an abnormal joint load, which may increase the risk of damage to the cartilage and the menisci.     

Is There a Gold Standard for TKA Tibial Component Rotational Alignment?

Background

Joint function and durability after TKA depends on many factors, but component alignment is particularly important. Although the transepicondylar axis is regarded as the gold standard for rotationally aligning the femoral component, various techniques exist for tibial component rotational alignment. The impact of this variability on joint kinematics and stability is unknown.

Questions/purposes

We determined how rotationally aligning the tibial component to four different axes changes knee stability and passive tibiofemoral kinematics in a knee after TKA.

Methods

Using a custom surgical navigation system and stability device to measure stability and passive tibiofemoral motion, we tested 10 cadaveric knees from five hemicorpses before TKA and then with the tibial component aligned to four axes using a modified tibial tray.

Results

No changes in knee stability or passive kinematics occurred as a result of the four techniques of tibial rotational alignment. TKA produces a ‘looser’ knee over the native condition by increasing mean laxity by 5.2°, decreasing mean maximum stiffness by 4.5 N·m/°, increasing mean anterior femoral translation during passive flexion by 5.4 mm, and increasing mean internal-external tibial rotation during passive flexion by 4.8°. However, no statistically or clinically important differences occurred between the four TKA conditions.

Conclusions

For all tibial rotations, TKA increased laxity, decreased stiffness, and increased tibiofemoral motion during passive flexion but showed little change based on the tibial alignment.

Clinical Relevance

Our observations suggest surgeons who align the tibial component to any of the axes we examined are expected to have results consistent with those who may use a different axis.     

Kinematics of medial osteoarthritic knees before and after posterior cruciate ligament retaining total knee arthroplasty

Total knee arthroplasty (TKA) is a widely accepted surgical procedure for the treatment of patients with end‐stage osteoarthritis (OA). However, the function of the knee is not always fully recovered after TKA. We used a dual fluoroscopic imaging system to evaluate the in vivo kinematics of the knee with medial compartment OA before and after a posterior cruciate ligament‐retaining TKA (PCR‐TKA) during weight‐bearing knee flexion, and compared the results to those of normal knees. The OA knees displayed similar internal/external tibial rotation to normal knees. However, the OA knees had less overall posterior femoral translation relative to the tibia between 0° and 105° flexion and more varus knee rotation between 0° and 45° flexion, than in the normal knees. Additionally, in the OA knees the femur was located more medially than in the normal knees, particularly between 30° and 60° flexion. After PCR‐TKA, the knee kinematics were not restored to normal. The overall internal tibial rotation and posterior femoral translation between 0° and 105° knee flexion were dramatically reduced. Additionally, PCR‐TKA introduced an abnormal anterior femoral translation during early knee flexion, and the femur was located lateral to the tibia throughout weight‐bearing flexion. The data help understand the biomechanical functions of the knee with medial compartment OA before and after contemporary PCR‐TKA. They may also be useful for improvement of future prostheses designs and surgical techniques in treatment of knees with end‐stage OA. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:40–46, 2011     

Influence of Component Rotation in Total Knee Arthroplasty on Tibiofemoral Kinematics—A Cadaveric Investigation

Background

Physiological tibiofemoral kinematics have been shown to be important for good knee function after total knee arthroplasty (TKA). The purpose of the present study was to investigate the influence of component rotation on tibiofemoral kinematics during knee flexion. We asked which axial component alignment best reconstructs physiological tibiofemoral kinematics and which combinations should be avoided.

Impulse-forces during walking are not increased in patients with knee osteoarthritis

Background?Impulsive forces in the knee joint have been suspected to be a co-factor in the development and progression of knee osteoarthritis. We thus evaluated the impulsive sagittal ground reaction forces (iGRF), shock waves and lower extremity joint kinematics at heel strike during walking in knee osteoarthritis (OA) patients and compared them to those in healthy subjects.

Subjects and methods?We studied 9 OA patients and 10 healthy subjects using three-dimensional gait analyses concentrated on the heel strike. Impulse GRF (iGRF) was measured together with peak accelerations (PA) at the tibial tuberosity and sacrum. Sagittal lower extremity joint angles at heel strike were extracted from the gait analyses. As OA is painful and pain might alter movement strategies, the patient group was also evaluated following pain relief by intraarticular lidocaine injections.

Results?The two groups showed similar iGRF, similar tibial and sacral PA, and similar joint angles at heel strike. Following pain relief, the OA patients struck the ground with more extended hip and knee joints and lower tibial PA compared to the painful condition. Although such changes occurred after pain relief, all parameters were within their normal ranges.

Interpretation?OA patients and healthy subjects show similar impulse-forces and joint kinematics at heel strike. Following pain relief in the patient group, changes in tibial PA and in hip and knee joint angles were observed but these were still within the normal range. Our findings make us question the hypothesis that impulse-forces generated at heel strike during walking contribute to progression of OA.