Contralateral Normal Knee Research Articles

Arthroscopic medial meniscectomy on stable knees.

We reviewed 74 partial medial meniscectomies in 57 patients with stable knees, to assess the long-term functional and radiological outcome. The International Knee Documentation Committee score and the residual laxity were assessed in both knees. At the time of surgery the mean age of the patients was 36 +/- 11 years and the mean follow-up was 12 +/- 1 years. All had a limited medial meniscectomy. The anterior cruciate ligament was intact in all cases. The meniscal tear was vertical in 95% and complex in 5%. The posterior part of the meniscus was removed in 99%. A peripheral rim was preserved in all cases. After 12 years 95% of the patients were satisfied or very satisfied with their knee(s). Objectively, 57% had grade A function and 43% were grade B. The outcome correlated only with the presence of anterior knee pain at final follow-up. In the 49 cases of arthroscopic meniscectomy for which there was a contralateral normal knee there was narrowing of the 'joint-space' in 16% of the operated knees. There was no correlation between this and other parameters such as age or different meniscal pathologies.

Arthroscopic medial meniscectomy on stable knees

We reviewed 74 partial medial meniscectomies in 57 patients with stable knees, to assess the long-term functional and radiological outcome. The International Knee Documentation Committee score and the residual laxity were assessed in both knees. At the time of surgery the mean age of the patients was 36 ± 11 years and the mean follow-up was 12 ± 1 years. All had a limited medial meniscectomy. The anterior cruciate ligament was intact in all cases. The meniscal tear was vertical in 95% and complex in 5%. The posterior part of the meniscus was removed in 99%. A peripheral rim was preserved in all cases. After 12 years 95% of the patients were satisfied or very satisfied with their knee(s). Objectively, 57% had grade A function and 43% were grade B. The outcome correlated only with the presence of anterior knee pain at final follow-up. In the 49 cases of arthroscopic meniscectomy for which there was a contralateral normal knee there was narrowing of the ‘joint-space’ in 16% of the operated knees. There was no correlation between this and other parameters such as age or different meniscal pathologies.

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.

TIBIAL ROTATION STRENGTH DEFICITS POST-ACL RECONSTRUCTION: HAMSTRING vs. PATELLAR TENDON AUTOGRAFTS

1761 Approximately 50,000 ACL reconstructions are performed in the United States annually1. While many (76%) surgeons use bone-patella tendon-bone (BTB), 21% use (medial) hamstring autographs for their primary reconstruction2. The purpose of this study was to determine internal tibial rotation (ITR) and external tibial rotation (ETR) peak torque differences between hamstring and BTB reconstructed patients. Patient inclusion criteria were: ≥ 1yr. post surgery and a normal contralateral knee. 46 patients, 23 (16 male, 7 female) treated with BTB autograft and 23 (9 male: 14 female) treated with hamstring autograft reconstruction were positioned on a Cybex in a supine position with the hip at 60° and the knee and ankle at 90° of flexion. Five maximal, concentric, ITR and ETR peak torque values were recorded and averaged during three isokinetic speeds (60, 120, 180°/sec). Relative ITR and ETR peak torque deficits were calculated by subtracting the absolute score of the involved limb from the score of the uninvolved limb. Between group, relative ITR and ETR peak torque deficits were compared using an unpaired t-test (p ≤ 0.05). Results showed that relative ITR peak torque deficits of the hamstring group were 2.6, 3.0 and 3.2 foot/lbs. at angular velocities of 60, 120, and 180°/sec. The relative ITR peak torque of BTB group were 0.7, 0.3, and 0.4 foot/lbs. There were significant differences between the magnitudes of relative ITR peak torque deficits at all speeds (p ≤ 0.02). The relative ETR peak torque deficits of the hamstring group were −0.7, 0.0, and −0.7 foot/lbs. at speeds of 60, 120, and 180°/sec. The relative ETR peak torque deficits of the BTB group were 2.4, 2.1, and 1.6 foot/lbs. There were significant differences between the magnitudes of the ETR peak torque deficits between groups at all speeds (p ≤ 0.01). The type of ACL reconstruction surgery has a residual effect on the ability to generate ITR and ETR peak torque.

The effect of knee flexion angle on knee stiffness values obtained using the Leicester arthrometer

Knee stiffness was measured in 20 patients with a unilateral ACL-deficiency at 0°, 20° and 65° of knee flexion, respectively. The reduction in stiffness when the ACL deficient knee was compared with the normal contralateral knee was 46, 39 and 39%. The differences between these values were not statistically significant. The data raise the possibility that the angle at which instrumented measurement is made may not be critical provided the deficient knee is compared with the normal knee at the same angle.

A methodology for the quantitative assessment of articular cartilage histomorphometry

Traditionally, histological analysis of cartilage and cartilage repair has been performed qualitatively. While new techniques and grading systems have attempted to improve the quantitative nature of histological assessment, the advent of computer-based analysis systems have enabled development of more quantitative methodologies for cartilage repair. The objective of this study was to develop such a methodology for a more quantitative assessment of cartilage repair using a color-based image analysis system. Repair parameters were defined to describe the degree of cartilage restoration: repair dimensions, degree of attachment, surface roughness and repair location. This technique was experimentally applied to a cartilage repair study using cultured perichondrial cells implanted in a polylactic acid matrix in the rabbit femoral condyle. Specimens were examined and compared with the contralateral normal knee. Results showed increases in cartilage height, repair area, and surface roughness over controls for both 6 and 12 weeks. Surface elevation was significantly decreased at 6 weeks over 12 weeks. The percentage of repair improved between 6 and 12 weeks. Results were compared with a traditional grading system and demonstrated close correlation. Intraobserver and interobserver precision analysis were performed and demonstrated the reproducibility of the quantitative results by and between individuals. The methodology was deemed successful for a more objective analysis of cartilage with the added advantage of providing measured parameters that can assist in making comparisons between different studies using the same methodology.

In vivo rotational stability of the kinematic rotating hinge knee prosthesis.

The in vivo rotary laxity and torsional stiffness of the knee joint were measured in 20 patients with wide intraarticular resection of the distal femoral tumor followed by reconstruction with a custom Kinematic rotating hinge endoprosthesis. The contralateral normal knee served as natural control. Twenty patients underwent 29 measurements, including 9 at the first year, 10 at the second year (4 of these also measured at year 1), and 10 at the third year (3 of these also measured at years 1 and 2; 2 also measured at year 2). The mean followup for the 15 survivors was 134 months (range, 102-156 months). The total rotatory laxity of the hinged knee was significantly greater than that of the contralateral knee. The torsional stiffness in external rotation of the hinged knee was 30.4% less than that of the contralateral knee in the first postoperative year, whereas the torsional stiffness in internal rotation was similar to that of the contralateral knee. Torsional stiffness of the hinged knee in the second year was significantly less than that of the contralateral knee whereas it was within the normal range of stiffness in the third year. The total rotatory laxity and torsional stiffness of the hinged knee in the early postoperative years could not predict the risk of late loosening. In vitro rotational stability of the rotating hinge device with axial load bearing was 6.7 and 8.1 Newton-meters (N-m) at 0 degrees and 20 degrees knee flexion, respectively, under an axial tibial load of 945 Newtons.

Anterior cruciate ligament injury rehabilitation in athletes. Biomechanical considerations.

Postoperative rehabilitation is a major factor in the success of an anterior cruciate ligament (ACL) reconstruction procedure. Clinical investigations of patients after ACL reconstruction have shown that immobilisation of the knee, or restricted motion without muscle contraction, leads to undesired outcomes for the articular, ligamentous, and musculature structures that surround the knee. Early joint motion is beneficial for; reducing pain, capsular contractions, articular cartilage, and for minimising scar formation that limit joint motion. These findings, combined with graft materials that have biomechanical properties similar to the normal ACL, and adequate fixation strength, have led many to recommend aggressive rehabilitation programmes that involve contraction of the dominant quadriceps muscles. Recently, a prospective, randomised study of rehabilitation following ACL reconstruction has presented evidence that a closed kinetic chain exercise programme (foot fixed against a resistance) results in anterior-posterior knee laxity values that are similar to the contralateral normal knee. Also, open kinetic chain exercises (foot not fixed against a resistance) result in increased anterior-posterior knee laxity compared with the normal knee. Criteria must be observed because the relationship between rehabilitation exercises and the healing response of an ACL graft is unknown at present. Biomechanical studies of healing ACL grafts performed in animals have shown that the graft requires a long time to revascularise and heal, and that the biomechanical behaviour of the graft never returns to normal. Functional knee braces provide a protective strain-shielding effect on the ACL when anterior shear loads and internal torques are applied to the knee in the non-weight-bearing condition. However, the strain shielding effect of functional braces decrease as the magnitude of anterior shear and internal torque applied to the knee increase. Future studies should strive to determine the actual loads transmitted across the knee and ACL graft strain during various rehabilitation exercises and relate these to the healing response of the knee and graft.

Intraoperative force‐setting did not improve the mechanical properties of an augmented bone‐tendon‐bone anterior cruciate ligament graft in a goat model

It has been hypothesized that load affects the mechanical properties of an anterior cruciate ligament graft while it remodels. The goal of this study was to use an existing goat model to evaluate the effect of intraoperative set force on the postoperative mechanical properties of an autograft that had been augmented with a synthetic segment. The following questions were addressed. Do augmented autografts set with a high force intraoperatively have improved structural and material graft properties and lower anterior-posterior knee laxity at 3 months after surgery, compared with autografts set with a low intraoperative force? How do the structural and material properties of these implanted autografts compare with the mechanical properties of an intact anterior cruciate ligament or an unimplanted control autograft? The anterior cruciate ligament was reconstructed in seven goats with use of a composite graft consisting of a bone-patellar tendon-bone autograft and a synthetic augmentation device. A force-setting technique was used intraoperatively to establish the load-sharing between the autograft and augmentation segments such that the autograft carried either a high (16.5 N in four animals) or low (1.5 N in three animals) level of force, while the total force in the composite graft remained constant. Tensile testing was performed at 3 months after surgery to determine the material and structural properties of the autograft, the intact anterior cruciate ligament from the normal contralateral knee, and a control bone-patellar tendon-bone graft of similar size that was harvested from the contralateral knee at the time of necropsy and had never been implanted in the joint. The structural and material properties of the autografts initially set to high or low loads at surgery were not significantly different after 3 months of implantation. The strength and stiffness of the implanted tendons were an average of 24 and 20% of the strength and stiffness of the normal anterior cruciate ligament and 31 and 62% of the control tendons, respectively. Intraoperative set force in an augmented anterior cruciate ligament graft at the levels chosen in this study did not significantly affect weakening of the autograft at 3 months.

Three-dimensional knee joint movements during a step-up: evaluation after anterior cruciate ligament rupture.

The three-dimensional motions of the knee were analysed during closed kinetic chain knee extension in 13 patients with unilateral chronic injury of the anterior cruciate ligament. The patients ascended a platform, and serial stereophotogrammetric roentgenograms were exposed from about 100 degrees of flexion to full extension. From a position of about 100 degrees of knee flexion and 20 degrees of internal rotation, the tibia rotated externally during the extension. Almost no tibial adduction or abduction was observed. The tibial intercondylar eminence translated laterally, distally, and anteriorly relative to the femur. In knees with absence of the anterior cruciate ligament, the intercondylar eminence had a more posterior position compared with the contralateral normal knees. The proximal tibia was used as a fixed reference segment to evaluate the anteroposterior translations of a central point in the femoral condyles. The femoral point was more anteriorly displaced in the injured than in the contralateral knees. This difference might reflect increased activity of the hamstrings in the injured knees, because it was most pronounced at 80 degrees of flexion and decreased with increasing extension. In the sagittal plane, the mean helical axis was positioned close to the femoral insertion of the ligament at 80 degrees of flexion and was displaced distally and anteriorly during extension. In the frontal plane, the axis had a transverse direction at 80 degrees of flexion. At close to full extension, the axis was positioned distally in the lateral condyle and proximally in the medial condyle. In the horizontal plane, the helical axes ran slightly more anteriorly in the medial than in the lateral femoral condyle but changed inclination at close to full extension and became almost parallel to the transverse axis.

Knee Joint Proprioception Revisited

Extensive histological studies have now confirmed a definite link between the anterior cruciate ligament (ACL) and the central nervous system. Preliminary histological evidence indicates that this neurological connection may be restored following reconstruction utilizing a free graft. In spite of this apparent graft reinnervation, clinical studies indicate that proprioception in the reconstructed knee probably remains inferior to that of the contralateral normal knee. A number of abnormalities of gait, reflexes, and muscle firing patterns have been discovered following an ACL tear. The degree to which a successful repair or reconstruction corrects these abnormalities remains uncertain, but again it appears that some abnormalities remain even during normal walking. Increased activity of the hamstrings as well as of the vastus lateralis, tibialis anterior, and medial gastrocnemius seems to be an adaptive mechanism to stabilize the knee after ACL injury. These muscle firing patterns seem to be trainable to some degree and should be incorporated into postinjury and postsurgical rehabilitation protocols.

V-Y Quadricepsplasty in Total Knee Arthroplasty

The results in 14 consecutive patients (16 knees) who have had total knee arthroplasty (TKA) with a V-Y quadricepsplasty were reviewed. There were eight men and six women with an average age of 66.2 years. Nine patients (ten knees) had revision arthroplasty and five patients (six knees) had primary arthroplasty. Nine of the 14 patients were examined and evaluated in the biomechanics laboratory using the modified Cybex-II system at a mean of three years from surgery. Using the knee rating score of the Hospital for Special Surgery, there were two excellent, ten good, two fair, and two poor results. The average active range of motion was 4 degrees to 85 degrees. Biomechanical testing revealed statistically significant weakness in extension compared with the contralateral side only at test speeds of 120, 180, and 240 degrees per second in those patients who had contralateral normal knees. The affected side at other test speeds were weaker but did not reach statistically significant weakness when compared with the contralateral knee. Comparing V-Y quadricepsplasty to normal medial parapatellar TKA patients, the extensor mechanism was weaker in the V-Y group but not to a significant degree. If one requires a V-Y quadricepsplasty during TKA, one can expect near normal active extension and moderate weakness in extension. Knee scores reflect the difficult reconstructive challenges that are inherent in patients who require a V-Y quadricepsplasty.

Knee Joint Proprioception Following Anterior Cruciate Ligament Reconstruction

This study evaluated knee joint position sense in the ACL-reconstructed and contralateral normal knees of 48 male and female subjects (M age 27.6 ± 6.9 yrs). Subjects were blindfolded and tested on their ability to actively reproduce five passively placed knee positions at 5° intervals between 35 and 15° of knee flexion. Mean algebraic target angle error and mean absolute error values were measured in degrees. The grand mean absolute error for the postsurgical knees at all positions was 5.4 ± 3.2°, compared with 5.2 ± 2.7° for the normal contralateral knees. There were no significant differences in knee joint position sense between the postsurgical and normal contralateral limbs at any of the five positions tested. Pivot shift, anterolateral rotatory instability, and Lachman test results were poorly correlated with knee joint position sense. The results suggest that if knee joint position sense was indeed disrupted by ACL injury and reconstructive surgery, related sensory mechanisms compensated for any proprioceptive loss prior to the minimum 2-yr postsurgical follow-up period employed in our study.

Long-term evaluation of knee stability and function following surgical reconstruction for anterior cruciate ligament insufficiency.

Currently used measures of knee stability and function for ACL reconstructed knees have not gained universal acceptance. Clinical test results often are given more value than the patient's subjective evaluation of the surgical outcome. This study was designed to identify specific knee stability and function variables that were most predictive of the patient's rating of knee function following one of two types of combined (intraarticular and extraarticular) ACL reconstruction procedures. Individual measures of knee stability and function were also evaluated for differences between contralateral operated and nonoperated limbs. Postoperative and healthy contralateral knees of 51 male and female patients aged 18 to 49 years (mean, 23.7 years) were evaluated on a battery of tests at an average of 48.0 months after surgery (range, 24 to 101 months). All subjects possessed a normal contralateral knee for comparative purposes. The results of this retrospective study indicated that the variables selected were not highly correlated with, nor could they effectively predict, the patients' perceptions of postoperative knee status as measured by the Knee Function Rating Form (KFR). Statistically significant differences (P less than 0.001) between operated and nonoperated knees were found for 9 of 11 variables analyzed. The data suggest that patients' perceptions of postoperative knee status were independent of the results of static and dynamic clinical tests commonly used to assess knee stability and function. Postoperative deficits of up to 30% between the surgically reconstructed and normal contralateral knees on specific measures of knee stability and function did not greatly influence the patients' perceptions of knee function. Development of new, more specific dynamic tests may be necessary before stronger relationships between clinical test results and patients' perceptions of knee status in the ACL reconstructed knee can be realized.

Effect of osteochondral defects on articular cartilage. Contact pressures studied in dog knees.

Full thickness osteochondral defects 6 mm in diameter were created in the weight-bearing regions of the femoral condyles in 5 adult mongrel dogs to study the contact pressure changes accompanying healing. A digital imaging technique employing Fuji Prescale film mapped contact pressures following 11 months of healing for comparison with contralateral normal knees, and knees with freshly made defects. Although all defects healed uneventfully with subchondral plate reconstitution and with growth restoration of the articular surface, the repair soft tissue appeared histologically to be primarily fibrous tissue, with varying degrees of a fibrocartilaginous component. The mean and peak stresses about fresh defects were not appreciably different from those about healed defects. Neither were there substantial differences in the total cartilage area making contact, except when very low loads were applied. The results suggest that the repair tissue is of poor mechanical quality, and does not contribute appreciably to weight bearing. The cartilage adjacent to the defect did not experience high stresses; neither gross nor light microscopic evidence of degeneration appeared at 11 months. If degeneration does occur following such defects, our data suggest that it is not because of elevated contact stresses.

Rotation‐plasty: Surgical technique of resection and reconstruction in the treatment of osteosarcoma about the knee in children

AbstractResection of malignant tumors about the knee, followed by reconstruction of the lower limb by rotating it through an arc of 180 degrees is becoming a popular method of treatment of osteosarcoma in growing children. Following rotation, the rotated ankle functions as the knee joint, powering a custom‐made prosthesis. The functional result is superior to above‐knee amputation with better propioceptive feedback and the absence of phantom limb pain. The children are able to climb stairs well and participate in running sports.The surgical technique is demanding, requiring a precise knowledge of the surgical anatomy. To be successful, the sciatic, peroneal, and tibial nerves must be preserved. The femoral and popliteal artery may be resected and reconstructed if necessary. The remaining growth of the child is determined so that the rotated ankle can be positioned at the level of the contralateral normal knee.