History Of Knee Pathology Research Articles

RELIABILITY OF NOVEL ULTRASOUND MEASUREMENT FOR DETERMINING PATELLA POSITION

Background:Patellar dislocations are common among youth athletes. A detailed understanding of patellofemoral anatomy is critical to determine patient prognosis and guide treatment and decision making. Recent literature suggests that measures of patella position relative to the trochlear groove may help identify individuals at risk of repetitive dislocations. While these measures were described using MRI, it is plausible that ultrasound imaging can be utilized to provide similar information in a more cost-effective and time-efficient manner.Purpose:To determine intra and inter-rater reliability of two newly described ultrasound-based measures of patella positioning within two novice examiners.Methods:Subjects were seated with the limb supported in full knee extension and neutral rotation. (Figure 1a) The examiners independently gathered all images and were blinded to each other’s measures for the duration of the study. The transducer was positioned transversely, on the anterior aspect of the knee such that the lateral trochlear ridge, center of trochlear groove, and proximal portion of the patellar tendon were all visible in cross-section. (Figure 1b) Two linear measures were obtained, representing the distance from midpoint of the patellar tendon to a) the center of trochlear groove (MPT-CTG) and b) the lateral trochlear ridge (MPT-LTR). Reliability was assessed using intraclass correlation coefficients (ICC). The average of two measures were used for data analysis. There was a minimum of 1 week between assessments for those subjects with repeated testing.Results:A total of 11 subjects (mean age 15.3) without history of knee pathology were included. There were no significant differences (p>0.05) in either measurement between limbs with MPT-CTG and MPT-LTR values (mean±sd) as follows: MPT-CTG right 8.4mm ± 3.0, left 8.4mm ± 3.3; MPT-LTR right 12.2mm ± 2.7, left 11.6mm ± 2.3. For reliability analysis, each knee served as a discrete variable, yielding a total of 22 data points for evaluation. Inter-rater reliability (n=22) was moderate to good for both measures, with ICC values of 0.724 and 0.814 for MPT-CTG and MPT-LTR, respectively. Intra-rater reliability (n=10) was good to excellent with ICC values of 0.913 and 0.794 for MPT-CTG and MPT-LTR, respectively. (Table 1)Conclusions:This new measure of patella positioning demonstrated moderate to excellent reliability and may be a practical, cost-effective alternative to MRI. While it is encouraging that the subjects in this sample demonstrated no side-to-side differences in either measure, future research should focus on establishing criterion validity and reliability amongst individuals with patellar instability.Figure 1.

Hamstring Autograft for Foot and Ankle Applications

Category: Ankle, Sports Introduction/Purpose: Hamstring tendon autografts (gracilis and/or semitendinosus) may be used as an alternative to allograft or local tendon grafts in foot and ankle surgery, primarily for tendon or ligament repairs in which direct repair has failed or is not possible. Advantages of hamstring autografts include avoiding the expense and lower healing potential of allografts, as well as the morbidity associated with local tendon grafts. While hamstring harvest has been abundantly studied in the setting of concomitant knee surgeries, few authors have investigated its effects when used specifically for foot and ankle applications. We studied a cohort of patients who underwent hamstring harvest for foot and ankle applications, hypothesizing that morbidity to the knee would be limited and foot and ankle outcome scores would be good. Methods: All patients who underwent hamstring autograft for foot or ankle applications by a fellowship-trained sports surgeon since 2011 were screened for inclusion. Patients were eligible if they were over the age of 18, had no history of knee pathology, and were at least one year from surgery. 23 patients were enrolled an average of 23 months post-operatively (range, 12-59 months). The average age was 51 ± 18 (range, 18-77) and 50% were women. Isokinetic testing was performed using a Biodex dynamometer, with the administering physical therapist blinded to side of surgery. Peak flexion and extension torque as well as flexion and extension torque at 30, 70, and 90 degrees of flexion were collected at two different testing speeds, 180 and 300 degrees/second. Pre- and post-operative questionnaire scores—the Foot and Ankle Outcome Score (FAOS) and Short Form (SF)- 12—were retrospectively reviewed. T-tests were used for all comparisons. Results: Of the 23 patients enrolled, gracilis was harvested in 14, semitendinosus in six, and both tendons in three to reconstruct the lateral ankle ligaments (eight patients), tibialis anterior (six), Achilles (five), and peroneus brevis (four). At follow-up, 19 patients (83%) reported no pain at the harvest site; the remaining four patients reported mild to moderate symptoms. There were no significant differences between relative flexion strength at different degrees of flexion or between relative flexion and extension strength, with strength considered as a percentage of that of the non-operated leg (Table). All five FAOS subscales and the SF-12 physical component subscale improved significantly (p=0.01 for all). No patients were dissatisfied and all would recommend the surgery to someone else. Conclusion: When used for foot and ankle surgery, hamstring autografts result in good functional outcomes and high patient satisfaction, with few patients experiencing symptoms from the harvest site at follow-up. Although our study was limited by its small number of patients and lack of preoperative isokinetic testing for comparison, effects on knee flexion strength do not appear to be clinically significant. Further work with larger numbers of patients will be required to identify small effects on knee flexion strength and to delineate differences between harvesting gracilis and semitendinosus.

Is valgus unloader bracing effective in normally aligned individuals: implications for post-surgical protocols following cartilage restoration procedures

Utilizing valgus unloader braces to reduce medial compartment loading in patients undergoing cartilage restoration procedures may be an alternative to non-weightbearing post-operative protocols in these patients. It was hypothesized that valgus unloader braces will reduce knee adduction moment during the stance phase in healthy subjects with normal knee alignment. Gait analysis was performed on twelve adult subjects with normal knee alignment and no history of knee pathology. Subjects were fitted with an off-the-shelf adjustable valgus unloader brace and tested under five conditions: one with no brace and four with increasing valgus force applied by the brace. Frontal and sagittal plane knee angles and external moments were calculated during stance via inverse dynamics. Analyses of variance were used to assess the effect of the brace conditions on frontal and sagittal plane joint angles and moments. With increasing tension in the brace, peak frontal plane knee angle during stance shifted from 1.6° ± 4.2° varus without the brace to 4.1° ± 3.6° valgus with maximum brace tension (P = 0.02 compared with the no brace condition). Peak knee adduction moment and knee adduction impulse decreased with increasing brace tension (main effect of brace, P < 0.001). Gait velocity and sagittal plane knee biomechanics were minimally affected. The use of these braces following a cartilage restoration procedure may provide adequate protection of the repair site without limiting the patient's mobility.

Comparison of Kneelax and KT-1000 Knee Ligament Arthrometers

Two commercially available knee ligament arthrometers (KT-1000 MEDmetric Corporation, San Diego, California and Kneelax MR Systems, Haarlem, The Netherlands) were used to measure anterior tibial translation. In this study 91 subjects with no history of knee pathology were tested using both devices. Both normal knees were tested and comparison of recorded anterior translation (millimeters) was performed. Absolute numbers at forces of 67N, 89N, 134N, and manual maximum displacements were recorded. Side-to-side differences were calculated and data were compared. There was a significant difference found between the absolute values of each device. The KT-1000 was found to record greater values in millimeters of translation. Although the absolute values were significantly different, the side-to-side differences were not significantly different between devices.

Comparison of MRI-Based Estimates of Articular Cartilage Contact Area in the Tibiofemoral Joint

Knee osteoarthritis (OA) detrimentally impacts the lives of millions of older Americans through pain and decreased functional ability. Unfortunately, the pathomechanics and associated deviations from joint homeostasis that OA patients experience are not well understood. Alterations in mechanical stress in the knee joint may play an essential role in OA; however, existing literature in this area is limited. The purpose of this study was to evaluate the ability of an existing magnetic resonance imaging (MRI)-based modeling method to estimate articular cartilage contact area in vivo. Imaging data of both knees were collected on a single subject with no history of knee pathology at three knee flexion angles. Intra-observer reliability and sensitivity studies were also performed to determine the role of operator-influenced elements of the data processing on the results. The method's articular cartilage contact area estimates were compared with existing contact area estimates in the literature. The method demonstrated an intra-observer reliability of 0.95 when assessed using Pearson's correlation coefficient and was found to be most sensitive to changes in the cartilage tracings on the peripheries of the compartment. The articular cartilage contact area estimates at full extension were similar to those reported in the literature. The relationships between tibiofemoral articular cartilage contact area and knee flexion were also qualitatively and quantitatively similar to those previously reported. The MRI-based knee modeling method was found to have high intra-observer reliability, sensitivity to peripheral articular cartilage tracings, and agreeability with previous investigations when using data from a single healthy adult. Future studies will implement this modeling method to investigate the role that mechanical stress may play in progression of knee OA through estimation of articular cartilage contact area.

Effect of experimentally induced knee pain on standing balance in healthy older individuals

Standing balance is impaired in older individuals with knee pain. The extent to which this impairment is due to the effects of pain itself or other pathophysiological aspects related to the underlying musculoskeletal condition causing the pain is unclear. To isolate the influence of pain, this study evaluated the effect of experimentally induced knee pain on standing balance in healthy older individuals. We used a repeated-measures, within-subject design involving 12 healthy individuals aged 50-60 yr and with no history of knee pathology. Balance was tested during two randomly allocated experimental conditions: (i) control and (ii) knee pain induced by injection of hypertonic saline into the infrapatellar fat pad. Balance was measured using a computerized force platform under static and dynamic conditions as well as via the functional step test. Standing balance was not significantly altered by experimentally induced acute knee pain, nor was there any relationship between the severity of reported pain and balance scores. Impairments in balance associated with knee conditions such as osteoarthritis may be due to factors other than the sensation of pain. Thus, strategies designed to reduce pain in treatment of knee pathology may not necessarily lead to improvements in balance. Further research is required to determine the exact causes of balance impairment in individuals with knee joint pain and pathology.

Effects of experimentally-induced anterior knee pain on knee joint position sense in healthy individuals

Purpose. The ability to sense the position of limb segments is a highly specialised proprioceptive function important for control of movement. Abnormal knee proprioception has been found in association with several musculoskeletal pathologies but whether nociceptive stimulation can produce these proprioceptive changes is unclear. This study evaluated the effect of experimentally induced knee pain on knee joint position sense (JPS) in healthy individuals. Study design. Repeated measures, within-subject design. Methods. Knee JPS was tested in 16 individuals with no history of knee pathology under three experimental conditions: baseline control, a distraction task and knee pain induced by injection of hypertonic saline into the infrapatellar fat pad. Knee JPS was measured using active ipsilateral limb matching responses at 20° and 60° flexion whilst non-weightbearing (NWB) and 20° flexion single leg stance. During the tasks, the subjective perception of distraction and severity of pain were measured using 11-point numerical rating scales. Results. Knee JPS was not altered by acute knee pain in any of the positions tested. The distraction task resulted in poorer concentration, greater JPS absolute errors at 20° NWB, and greater variability in errors during the WB tests. There were no significant correlations between levels of pain and changes in JPS errors. Changes in JPS with pain and distraction were inversely related to baseline knee JPS variable error in all test positions ( r = −0.56 to −0.91) but less related to baseline absolute error. Conclusion. Knee JPS is reduced by an attention-demanding task but not by experimentally induced pain.

Effect of fatigue on hamstring coactivation during isokinetic knee extensions.

We examined the effect of fatigue of the quadriceps muscles on coactivation of the hamstring muscles and determined if the response is different between two isokinetic speeds in ten males and ten females with no history of knee pathology. Electromyographic data were recorded from the vastus lateralis and biceps femoris muscles during 50 maximal knee extensions at isokinetic speeds of 1.75 rad x s(-1) (100 degrees x s(-1)) and 4.36 rad x s(-1) (250 degrees x s(-1)). A greater degree of coactivation was apparent at the higher speed, but the increase in coactivation of the hamstring muscles was similar at both speeds. The results revealed that: (1) coactivation is greater at a higher isokinetic speed, and (2) coactivation increases during fatigue, but the rate of increase is independent of contraction velocity.

Reliability of knee flexor peak torque measurements from a standardized test protocol on a Kin/Com dynamometer

Abstract The test-retest reliability of a specific test protocol for the measurement of peak torque of the knee flexors using a Kin/Com dynamometer was evaluated. The maximum voluntary torque generated by the left knee flexors during constant velocity resisted-muscle shortening (RMS) and muscle lengthening (RML) was measured in a sitting position in 11 healthy women with no history of knee pathology. Each subject performed two tests at each of two velocities (30°/sec and 180°/sec) in a single session. All subjects repeated these four tests one week later. A test consisted of four complete RMSRML cycles through a range of 65°. The peak torque generated from each test was used to measure test-retest reliability. All data were gravity compensated. Intraclass correlation coefficients (ICCs [1,1]) were calculated from ANOVA tests for RML and RMS at both velocities. The within sessions ICCs ranged from .94 to .98 for 30°/sec and from .92 to .97 at 180°/sec. The ICCs between sessions were generally lower and ranged from .79 to .90 for 30°/sec, and from .75 to .88 for 180°/sec. It is concluded that using these test protocols, peak torques for both RMS and RML can be measured with a high degree of reliability at two commonly used velocities.

A Comparison of the LIDO Sliding Cuff and the Tibial Control System in Isokinetic Strength Parameters

The purpose of this study was to compare the tibial controlsystem (TCS) and sliding cuff (SC) lever arms in the strengthparameters peak torque (PT), average work(AW), averagepower (AP), joint angle at peak torque (JA), and fatigueindex (FI). Fifteen healthy subjects, with no history of kneepathology, performed three knee extension/flexionrepetitions using the right leg at a velocity spectrum of 60,180, 240, and 20 repetitions at 300 deg/sec for each leverarm. TCS and SC were randomly presented with 24 hoursbetween conditions. Significance was set at p < 0.05. Pairedt tests showed that the SC produced significantly greater PT,AW, and AP than the TCS during extension across velocities .Also, SC JA occurred significantly later in the range ofmotion across velocities, whereas FI was significantly greaterfor the SC than the TCS at 300 deg/sec. Paired t tests forflexion data indicated that the TCS produced significantlygreater PT than the SC across velocities and greater AP at 60deg/sec. The SC condition resulted in significantly greaterAW and AP at 300 deg/sec only. The SC and TCS conditionsdid not differ for JA and Fl across velocities. It was concludedthat choice of lever arm significantly influenced the strengthparameters examined in this study.

Reliability of knee flexor peak torque measurements from a standardized test protocol on a Kin/Com dynamometer.

The test-retest reliability of a specific test protocol for the measurement of peak torque of the knee flexors using a Kin/Com dynamometer was evaluated. The maximum voluntary torque generated by the left knee flexors during constant velocity resisted-muscle shortening (RMS) and muscle lengthening (RML) was measured in a sitting position in 11 healthy women with no history of knee pathology. Each subject performed two tests at each of two velocities (30 degrees/sec and 180 degrees/sec) in a single session. All subjects repeated these four tests one week later. A test consisted of four complete RMS/RML cycles through a range of 65 degrees. The peak torque generated from each test was used to measure test-retest reliability. All data were gravity compensated. Intraclass correlation coefficients (ICCs) were calculated from ANOVA tests for RML and RMS at both velocities. The within sessions ICCs ranged from .94 to .98 for 30 degrees/sec and from .92 to .97 at 180 degrees/sec. The ICCs between sessions were generally lower and ranged from .79 to .90 for 30 degrees/sec, and from .75 to .88 for 180 degrees/sec. It is concluded that using these test protocols, peak torques for both RMS and RML can be measured with a high degree of reliability at two commonly used velocities.

Comparison of vastus medialis obliquus

The purpose of this study was to compare vastus medialis obliquus:vastus lateralis muscle (VMO:VL) integrated electromyographic (IEMG) ratios of healthy subjects and patients with unilateral patellofemoral pain (PFP) under isotonic and isometric quadriceps femoris muscle contraction conditions. Subjects ranging in age from 18 to 35 years (mean = 28.06, SD = 5.97) were assigned to one of three groups on the basis of type of knee condition. In group 1, which consisted of seven healthy control subjects with no history of knee pathology, both knees were tested. In group 2, which consisted of nine patients with unilateral PFP, only the painful knee was tested. In group 3, which consisted of the same nine patients who comprised group 2, only the nonpainful knee was tested. Nonnormalized and normalized VMO:VL IEMG ratios were computed for ascending stairs, descending stairs, submaximal isometric contraction, and maximal isometric contraction (nonnormalized only). A two-way analysis of variance for repeated measures indicated VMO:VL ratios for isotonic stair-climbing activities were significantly greater than VMO:VL ratios for isometric contractions. Nonnormalized VMO:VL ratios in group 1 were significantly greater than nonnormalized VMO:VL ratios in the other two groups. Patients with PFP may have abnormal VMO:VL activation patterns, and isotonic quadriceps femoris muscle exercise may elicit more favorable muscle activation patterns than isometric exercise for patients with PFP.

Comparison of Vastus Medialis Obliquus:Vastus Lateralis Muscle Integrated Electromyographic Ratios Between Healthy Subjects and Patients with Patellofemoral Pain

The purpose of this study was to compare vastus medialis obliquus:vastus lateralis muscle (VMO:VL) integrated electromyographic (IEMG) ratios of healthy subjects and patients with unilateral patellofemoral pain (PFP) under isotonic and isometric quadriceps femoris muscle contraction conditions. Subjects ranging in age from 18 to 35 years (mean = 28.06, SD = 5.97) were assigned to one of three groups on the basis of type of knee condition. In group 1, which consisted of seven healthy control subjects with no history of knee pathology, both knees were tested. In group 2, which consisted of nine patients with unilateral PFP, only the painful knee was tested. In group 3, which consisted of the same nine patients who comprised group 2, only the nonpainful knee was tested. Nonnormalized and normalized VMO:VL IEMG ratios were computed for ascending stairs, descending stairs, submaximal isometric contraction, and maximal isometric contraction (nonnormalized only). A two-way analysis of variance for repeated measures indicated VMO:VL ratios for isotonic stair-climbing activities were significantly greater than VMO:VL ratios for isometric contractions. Nonnormalized VMO:VL ratios in group 1 were significantly greater than nonnormalized VMO:VL ratios in the other two groups. Patients with PFP may have abnormal VMO:VL activation patterns, and isotonic quadriceps femoris muscle exercise may elicit more favorable muscle activation patterns than isometric exercise for patients with PFP.

Comparison of the Cybex II®Standard Shin Adapter Versus the Johnson Anti-Shear Device in Torque Generation

The purpose of this study was to determine if differences exist in peak torque and total work performed when the Johnson Anti-Shear Device was utilized as compared to the standard shin adapter during knee extension. The Cybex II,® in conjunction with the HUMAC computer system was used in this study. Twenty-seven healthy subjects, with no history of knee pathology, were tested on successive days at speeds of 60°/sec and 180°/sec. Results demonstrated a significant decrease (p < 0.05) in peak torque at low speeds as well as total work performed at high speeds when using the anti-shear device. The findings indicate that the clinician/researcher must be consistent with the choice of shin pad in order to ensure valid, reliable data.

The effect of a prior quadriceps contraction on knee flexor torque in normal subjects and multiple sclerosis patients with spastic paraparesis

The purpose of this study was to analyse the effect of a prior quadriceps contraction on knee flexor torque in normal subjects and multiple sclerosis patients. Twelve subjects (10 females, two males, mean age 34.8 years) with spastic paraparesis secondary to multiple sclerosis and 12 healthy adults, matched by age and sex, with no history of knee pathology participated in this study. A Cybex II isokinetic dynamometer and chart recorder were used to measure the torque and angle of peak torque produced during knee flexion at 30, 90 and 180°/s. The subjects performed two tests of knee flexion. In test one, the subjects maximally flexed their knee three times from a passively extended position. During the second test, the subjects maximally extended and then flexed their knee three times. The tests were randomly ordered and both lower extremities were tested. The subject's limbs were also passively dropped from an extended position at three preselected velocities (30, 90, 180°/s). The Cybex goniograms which w...