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Biomedical subjects

F R Noyes

Publications and source records attributed to F R Noyes.

At least 19 recordsLinked to original sources
PubMed1992

The correlation between anterior-posterior translation and cross-sectional area of anterior cruciate ligament reconstructions.

Total anterior-posterior translation is commonly used to assess the integrity of the cruciate ligaments and the success of reconstructive surgery. The purpose of this study was to determine, after surgical reconstruction of the anterior cruciate ligament with a biological graft, if total anterior-posterior translation correlated with graft length, cross-sectional area, or mechanical properties. These factors were investigated by analyzing data from three previous studies. These studies involved replacement of the anterior cruciate ligament in cynomolgus monkeys and goats, with free and vascularized patellar tendon autografts and both patellar tendon and anterior cruciate ligament allografts. Data were available at time periods of 6 and 12 months after surgery. We found statistically significant inverse correlations between the amount of anterior-posterior translation and cross-sectional area of a graft at the time of sacrifice. The Pearson correlation coefficients ranged from -0.966 (p < 0.002) to -0.830 (p < 0.05). We hypothesize that these correlations result from the following mechanism: the increased anterior translation reflects a slack graft; a slack graft is stress shielded by other structures about the knee; the reduced in vivo stresses on the graft modulate cellular metabolism in a way that over time produces a small cross-sectional area.

Analysis of Variance↗
PubMed1992

Cystic degeneration of the patella after arthroscopic chondroplasty and subchondral bone perforation.

Chondromalacia of the patella is frequently encountered in patients with anterior knee pain. Arthroscopic chondroplasty with perforation of subchondral bone remains a popular treatment alternative in spite of the inferior mechanical properties of the fibrocartilaginous tissue that this procedure is designed to promote. We report a case of cystic degeneration of the patella as a previously unrecognized complication following the procedure.

Adult↗
PubMed1992

Posterior tibial subluxation of the posterior cruciate-deficient knee.

Ten subjects with unilateral posterior cruciate ligament-deficient knees were studied, comparing the knee mechanics of the affected knee with the mechanics of the opposite normal knee. The static squat test was used to determine knee forces and moments through measurements made on roentgenograms. Statistically significant increases occurred in posterior translation of the tibia in all knees at high knee flexion angles, but not uniformly at low knee flexion angles. The results suggest that posterior tibial subluxation occurs in vivo during certain activities of daily living. Posterior tibial subluxation occurred in positions of knee flexion near 70 degrees, establishing a new equilibrium for the system where tibiofemoral joint compression force (approximately four times one-half body weight) remained an order of magnitude greater than tibiofemoral shear forces (approximately 10% of one-half body weight).

Adolescent↗
PubMed1992

The effect of a ligament-augmentation device on allograft reconstructions for chronic ruptures of the anterior cruciate ligament.

A prospective study was performed to determine the effect of a combination of a ligament-augmentation device with a bone-patellar ligament-bone allograft for the treatment of chronic rupture of the anterior cruciate ligament. One hundred and fifteen knees in 110 patients were divided into two groups. Group BLB consisted of sixty-six knees in sixty-four patients who were managed with a bone-patellar ligament-bone allograft only, and Group BLB-LAD consisted of forty-nine knees in forty-six patients who were managed with both the allograft and a ligament-augmentation device. Preoperatively, there were no statistically significant differences between the two groups with regard to fifteen variables. All patients were managed with the same postoperative program of immediate motion and rehabilitation of the knee. All patients returned for evaluation at a mean of thirty-four months (range, twenty-three to fifty-three months) postoperatively. The results were evaluated with a comprehensive rating system that assessed twenty factors. Both of these procedures significantly decreased functional limitations and symptoms and improved the level of sports activity and the over-all score. However, the use of the ligament-augmentation device did not improve the efficacy of the reconstruction with regard to any of the individual variables that were assessed or in terms of the over-all score. All but one of the patients regained an arc of 0 to 135 degrees of motion. Although the augmentation device reduced anterior-posterior displacement effectively for the first twenty weeks postoperatively (p less than 0.05), there was no difference between the groups in terms of the percentage of knees that had abnormal displacement at the latest follow-up. A new classification system was developed to determine rates of failure. The over-all rate of failure was 28 per cent (thirty-two) of the 115 knees: 29 per cent (nineteen) of the sixty-six knees in Group BLB and 27 per cent (thirteen) of the forty-nine knees in Group BLB-LAD. The difference between the two groups was not statistically significant. The addition of the ligament-augmentation device did not improve the results of allograft reconstruction in the treatment of chronic rupture of the anterior cruciate ligament. The use of either an allograft alone or an allograft combined with a ligament-augmentation device did not reduce the amount of anterior-posterior displacement satisfactorily in all of the knees.

Adolescent↗
PubMed1992

The early treatment of motion complications after reconstruction of the anterior cruciate ligament.

The use of active and passive knee motion in the immediate postoperative period and a treatment plan for early postoperative limitations in knee motion has proven highly effective in restoring motion after anterior cruciate ligament (ACL) reconstruction. Of 207 knees, 189 (91%) regained a full range of motion of 0 degrees-135 degrees. The remaining 18 knees (9%) did not regain motion as rapidly as the others and were placed in an early postoperative phased treatment program. Six knees had serial extension casts, nine had early gentle manipulation under anesthesia, and three had arthroscopic lysis of intraarticular adhesions and scar tissue. Fourteen of these 18 knees regained a full range of knee motion. Two of the remaining four knees lacked 5 degrees of full extension, whereas the other two, in patients who had failed to follow medical advice and the rehabilitation program, had permanent and significant limitation of motion. The incidence of postoperative motion problems was related to the extent of the surgical procedure. The incidence was 4% in patients who had only ACL reconstruction, 10% in cases in which added lateral extraarticular procedure had been done, 12% where a meniscus repair had been done, and 23% where a medial collateral ligament repair was done.

Adult↗
PubMed1992

Preoperative planning for high tibial osteotomy. The effect of lateral tibiofemoral separation and tibiofemoral length.

To calculate the tibial wedge size in preoperative planning of high tibial osteotomy, the weight-bearing line (center femoral head to center tibiotalar joint) is first restored to a selected position on the lateral tibial plateau. Ten full-standing roentgenograms were examined and used to derive mathematical formulas for correcting limb alignment. A 3-4-mm shift in the weight-bearing line on the tibia occurred with each degree of tibiofemoral angulation. This showed that the position of the weight-bearing line is sensitive to the lengths of the tibia and femur as well as the surgeon's preoperative calculations. The problem of increased varus angulation due to slack lateral ligament restraints with distraction of the tibiofemoral joint was analyzed. Trigonometric analysis showed that each millimeter of lateral tibiofemoral joint separation caused about 1 degree varus angular deformity, requiring subtraction in preoperative calculations to avoid overcorrection. An algorithm was designed to evaluate complex lower-limb alignments.

Adult↗
PubMed1991

Effects of gamma irradiation on the initial mechanical and material properties of goat bone-patellar tendon-bone allografts.

The effects of 60Co gamma irradiation on the initial mechanical properties of the composite bone-patellar tendon-bone unit (CU) and the tendon midsubstance (TM) were studied. Frozen specimens were exposed to either 2 or 3 Mrad of gamma irradiation. Paired frozen specimens served as intraanimal controls. Treatment effects on the CU were assessed using four mechanical parameters. Effects on the TM were assessed using four material parameters measured using an optical surface-strain analysis system. The maximum force and strain energy to maximum force of the composite unit were significantly reduced 27% and 40%, respectively, after 3 Mrad of irradiation (p less than .05). Mechanical properties of the CU were not significantly altered, however, following 2 Mrad of irradiation. Based on individual paired contrasts between treatment and control, significant differences were also found in the material properties of the tendon midsubstance. The maximum stress, maximum strain, and strain energy density to maximum stress were significantly reduced following 3 Mrad, but not 2 Mrad, of irradiation. The results provide important "time zero" material property data, which will be useful for later anterior cruciate ligament reconstruction studies using irradiated allograft patellar tendons in the goat model and other animal models as well.

Analysis of Variance↗
PubMed1991

Effect of flexion angle on the pressure-volume of the human knee.

The objective of this study was to determine pressure-volume relationships in the human knee. Eight normal knees in eight patients undergoing elective arthroscopic surgery were studied to develop pressure-volume curves at 0 degrees, 15 degrees, 30 degrees, 60 degrees, and 80 degrees of flexion, and measure capsular volume at 0 degrees, 15 degrees, 30 degrees, 45 degrees, 60 degrees, and 80 degrees of flexion. The results showed that capsular volume decreases with flexion, whereas capsular stiffness increases. This suggests that during arthroscopy, flexion with obstructed outflow may cause significant intraarticular pressure and potential rupture of synovial membranes. Our results support the concept of flow rates with low distension pressures for maximum safety.

Adult↗
PubMed1991

The early diagnosis and treatment of developmental patella infera syndrome.

Developmental patella infera and associated arthrofibrosis after knee surgery require prompt recognition and treatment. The condition develops because of contracture of peripatellar tissues, fatpad tissues, and quadriceps weakness, and may rapidly progress to permanent patella infera and disabling patellofemoral arthrosis. Case studies for five patients with acute developmental patella infera are described. All patients required an early arthroscopic release of contracted tissues. To establish normal right to left patellar, vertical-height ratios, lateral roentgenograms were obtained in 202 normal knees (101 pairs). The data showed that although essentially no difference existed between right and left sides, large variations existed in the ratios from one individual to another (range, 0.75-1.46). Thus, the diagnosis of developmental patella infera requires comparison of patellar height ratios in the same knee or between knees in the same individual. A decrease in the vertical-height ratio of 11%-15%, depending on the method used, indicates developmental patella infera.

Adolescent↗
PubMed1991

The effect of an extra-articular procedure on allograft reconstructions for chronic ruptures of the anterior cruciate ligament.

A study was performed on the effect of the addition of an extra-articular procedure involving tenodesis of the iliotibial band to a reconstruction with a bone-patellar ligament-bone allograft for the treatment of chronic rupture of the anterior cruciate ligament. One hundred and four patients were divided into two groups for comparison: Group 1 (sixty-four patients) was treated with only an intra-articular replacement with an allograft and Group 2 (forty patients), with both an intra-articular replacement with an allograft and the extra-articular procedure. Preoperatively, there were no statistically significant differences between the two groups in terms of twenty variables, including body weight, level of activity, anterior-posterior displacements, number of previous operations, and duration of follow-up. All of the patients returned for follow-up evaluation twenty-three to fifty-four months (mean, thirty-five months) postoperatively. All were treated with the same postoperative program of immediate motion of the knee and rehabilitation. The results were evaluated with the use of a comprehensive subjective and objective system that rated the twenty factors. Both procedures proved to be effective in decreasing functional limitations and symptoms and in improving the level of sports activity and the over-all scores. The results in Group 2 were significantly better than those in Group 1, as measured with tests done with the KT-1000 arthrometer (p less than 0.01) and with regard to the level of sports activity (p less than 0.05) and the over-all scores (p less than 0.01). There was no postoperative difference between the two groups in terms of the results on pivot-shift or isokinetic testing, patellofemoral crepitus, functional limitations, or symptoms. The program of rehabilitation effectively restored 0 to 135 degrees of motion to all but four knees, which lacked 5 degrees of extension at the most recent follow-up. The over-all rate of failure for both groups was 11 per cent. However, the rate of failure was 16 per cent (ten of sixty-four knees) in Group 1 and only 3 per cent (one of forty knees) in Group 2. This difference was significant (p less than 0.05). The extra-articular procedure appeared to provide support to the healing intra-articular allograft by reducing deleterious forces and tibial displacements, and to restore the secondary restraints provided by the lateral iliotibial band. The results suggest that the combination of the procedures is of value in young, athletically active people who have chronic rupture of the anterior cruciate ligament.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1990

Quantitative assessment of functional limitations in normal and anterior cruciate ligament-deficient knees.

The purpose of this study was to evaluate the effectiveness of five hopping, jumping, and cutting-type (shuttle run) tests in determining lower extremity functional limitations in anterior cruciate ligament- (ACL) deficient knees. Ninety-three normal subjects were tested. No statistical significance was found between right and left lower limb scores (limb symmetry index) as related to sports activity level, gender, or dominant side. This allowed an overall symmetry index score to be established for the population as a whole. An 85% symmetry index score was found in more than 90% of the normal population for the one-legged hop for distance test and the one-legged timed hop test. Thirty-five patients with ACL-deficient knees were tested. The patients also had KT-1000 and Cybex testing and completed questionnaires rating symptoms, sports activity levels, and sports functional limitations. The cutting-type tests and the vertical jump test did not detect functional limitations in a reliable manner. In the one-legged hop tests, 50% of the patients performed normally, however, all reported giving-way episodes with sports, indicating a lack of sensitivity of these tests in defining functional limitations. Patients with abnormal one-legged hop test scores were considered at serious risk for giving way and limitations during sports activities. Statistically significant relationships were found among abnormal scores on the one-legged hop-type tests and (1) self-assessed difficulty with pivoting, cutting, and twisting, (2) quadriceps weakness (Cybex), and (3) patellofemoral compression pain.

Adolescent↗