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Biomedical subjects

J Gillquist

Publications and source records attributed to J Gillquist.

At least 37 records · Page 2Linked to original sources
PubMed1995

Sagittal plane translation of the knee during stair walking in healthy volunteers measured by an electrogoniometer chain.

Maximal sagittal plane knee translation during stair walking was investigated in 5 healthy male subjects without any previous history of knee joint trauma during 2 types of ascents and descents (straight and side) using an electrogoniometer system (CA-4000, OS Inc., Hayward CA, USA). During the ascents, the tibia moved anteriorly in relation to femur, whereas during the descents it moved posteriorly. The maximum translations occurred within the range of 39 degrees to 51 degrees of knee flexion and were significantly larger during the ascents than during descents, but there was no difference between straight and side activities. There were significant interindividual differences in the maximum translations during the ascent or descent cycles but no differences between trials or the right or left limbs. The mean difference between repeated trials was 1.2 mm and the 95% confidence interval was +/- 0.6 mm.

Adult↗
PubMed1995

Outcome of arthroscopic meniscectomy. A 13-year physical and radiographic follow-up of 43 patients under 23 years of age.

We reexamined 43 patients with stable knees at a mean of 13 years after arthroscopic meniscectomy. The patients had a maximum age of 22 years at the operation and no patient had had previous surgery on the involved knee. At the follow-up examination, no differences in range of motion, muscle strength or tibial A/P displacement were seen between the operated and the nonoperated knees and 36 patients had no problem with their knee in daily life. Radiographic changes were found in the operated knee in 20 patients and in the nonoperated knee in 5 patients. 8 patients had a reduction of the joint space on the involved side, but none had more severe changes. Cartilage fibrillation at the index arthroscopy did not increase the radiographic changes at follow-up, but radiographic changes were commoner after subtotal meniscectomy (7/8) than after partial meniscectomy (17/35). These findings are similar to previous studies of arthroscopic meniscectomy of medium duration and do not differ considerably from studies of open meniscectomy.

Adolescent↗
PubMed1994

Acute patellar dislocation during eccentric muscle testing on the Biodex dynamometer.

Isokinetic training and muscle torque measurements are commonly used during rehabilitation after knee ligament injuries. Isokinetic maximal muscle strength tests are performed to monitor the progress in muscle rehabilitation. The muscle power is evaluated by measuring the applied force in the direction of motion (concentric muscle power) or the force against the direction of motion (eccentric muscle power). Both legs are examined to compare the total muscle work and peak torques of the involved leg with those of the uninvolved leg. We report the case of an acute patellar dislocation during eccentric testing of the uninvolved leg on the Biodex isokinetic dynamometer testing device (Biodex Corporation, Shirley, NY).

Acute Disease↗
PubMed1994

Tc-scintimetry in 56 cementless hip arthroplasties. A prospective, randomized comparison of two femoral components.

In a prospective, randomized study of cementless total hip arthroplasties, radionuclide images as well as radiographs were obtained at 6, 12, and 36 months postoperatively. The femoral component was porous-coated, rigid in 28 patients and smooth, isoelastic in 28. The radionuclide uptake was quantified in the regions of interest and correlated to the non-operated side. Among prostheses considered to be stable 3 years after surgery, the activity had normalized in the calcar region. The uptake was also reduced below the tip of the prostheses, but the activity was still 50 percent increased compared to the non-operated side. The isoelastic prosthesis showed less reduction of activity below the tip than the rigid prosthesis. Proximally, the isoelastic prosthesis showed no reduction of activity, whereas the rigid prosthesis had normalized the uptake at the 3-year control. A high rate of non-stable fixation was observed for the flexible prosthesis at the radiographic assessment, which may have contributed to the increased radionuclide activity. Sequential scintimetry may be used as a complement to the radiographic evaluation of the femoral component of the hip prosthesis.

Bone Remodeling↗
PubMed1993

Neocartilage after artificial cartilage repair in the rabbit: histology and proteoglycan fragments in joint fluid.

Repair of full-thickness cartilage defects of the rabbit medial femoral condyle with artificial plugs and periosteal grafts was followed for 1 year. The morphological characteristics of the neocartilage after repair and the concentration of proteoglycan fragments in the joint fluid (CPFF) were evaluated. The CPFF showed only a weak correlation to the histological score of the neocartilage. Normal cartilage and subchondral bone did not develop with any of the repair alternatives. With a Dacron plug, neocartilage formation appeared earlier than with natural repair and was better than with periosteal grafting. Increased CPFFs were found in all specimens with repair at 3 months, probably reflecting the remaining effect of surgery. At 6 months, the CPFFs had normalized to control values. At 1 year, the CPFFs were again similar to those at the 3-month evaluation. This was paralleled by a degeneration of the neocartilage. We conclude that Dacron plugs could serve as a scaffold for neocartilage formation. The CPFF reflected surgical trauma and late degeneration of neocartilage but did not indicate minor differences in quality between cartilage repair techniques, probably because of the limited size of the grafted defect.

Animals↗
PubMed1993

Prosthetic replacement of the rabbit medial meniscus.

Implants of polyurethane-coated polyester (Dacron), polyurethane-coated PTFE (Teflon), or uncoated PTFE were used to substitute the medial rabbit meniscus, and were observed over a 3-month period. Joint mechanics were similar for sham-operation, meniscectomy, or substitution with a coated implant. Joints with an uncoated PTFE prosthesis tended to be less compliant and to show greater load dissipation during relaxation. Cartilage indentation showed softening with all alternatives compared to sham-operation. Ingrowth into the prosthesis periphery was best with the PTFE implants. Both types of coated prosthesis retained their original shape, in contrast to the uncoated prostheses. To the naked eye the cartilage appeared unaffected only after sham-operation or implantation of a coated PTFE prosthesis. Osteophyte formation was common with all alternatives except sham-operation. We conclude that replacement of the medial meniscus with coated prostheses, especially the PTFE, was better than meniscectomy or using the uncoated prosthesis. However, cartilage softening and osteophyte formation indicate that joint mechanics were not restored to normal.

Animals↗
PubMed1993

Reconstruction of the posterior cruciate ligament using a new drill-guide.

In 40 normal cadaver knees from adults (mean age 29 years) the average length of the posterior cruciate ligament was 38 +/- 4 mm. The angle between the ligament and the long axis of the femur was 43.4 +/- 3 degrees with the knee in full extension. We studied the functional importance of different attachments of the posterior cruciate ligament. The distance between the central point of the normal attachment area on the tibia and the central proximal part of the femoral attachment area on the medial femoral condyle was found to change least during full range of knee motion. On the basis of the results in the present study we suggest some basic principles for a standardized replacement operation for a deficient posterior cruciate ligament using a new drill-guide. The drill-guide has been used in 14 consecutive patients (mean age 26 +/- 6 years) who underwent a reconstruction of the posterior cruciate ligament. The patients have been followed for 2 years. The Lysholm score increased significantly from 60 +/- 16 preoperatively to 76 +/- 15 (P < 0.001) at 2 years, and the stability, measured with a laxity tester, improved from 8 +/- 3 mm total excursion preoperatively to 6 +/- 3 mm at 2 years follow-up. The follow-up time is still short but the results seem to be promising.

Adolescent↗
PubMed1993

Cartilage mechanics and morphology, synovitis and proteoglycan fragments in rabbit joint fluid after prosthetic meniscal substitution.

The effects of meniscal substitution with a Dacron or Teflon prosthesis on rabbit knee-joint cartilage were studied by indentation tests, gross and histological inspection, analysis of proteoglycan fragments in joint fluid and an evaluation of synovial changes. Cartilage mechanics and cartilage morphology were similarly abnormal after meniscectomy and meniscal substitution. The elevated concentrations of proteoglycan fragments in joint fluid and the more severe synovial changes in joints with a meniscal substitute, as compared to meniscectomy, probably resulted from irritation of the artificial implant, but also reflected the remaining effects from the necessary bone drilling. In this short-term experiment, the use of an artificial meniscal substitute could not prevent cartilage degeneration after meniscectomy.

Analysis of Variance↗
PubMed1993

Synthetic implants for the repair of osteochondral defects of the medial femoral condyle: a biomechanical and histological evaluation in the rabbit knee.

Polyurethane-coated and uncoated polytetrafluoroethylene (PTFE) (Teflon) and polyester (Dacron) felts were used for repair of full-thickness cartilage defects in the rabbit knee. At 3 months the indentation characteristics and the histological appearance of the repairs were compared with those of a sham-operation, natural repair, and periosteal grafting. Joint compressive load-displacement and indentation characteristics of the cartilage adjacent to the defect were normal for all alternatives. All the repair sites had a higher compliance than had normal cartilage-bone, but synthetic grafting had values closer to normal than periosteal grafting. The adjacent cartilage appeared macroscopically normal, except with periosteal grafting and coated PTFE implants where it showed surface irregularities in some cases. With periosteal and uncoated synthetic implants the defects were completely filled, but not in the natural repair sites. Most of the coated implants failed by separation within the implant. On histological examination, ingrowth of trabecular bone from the base of the defect into the synthetic material was seen in all the specimens. The neocartilage 'score' was equally low with all the repairs reaching only one-third of the maximum points. All the repairs were associated with synovitis. Further, some of the knees with the synthetic materials repair had debris particles in the synovium. We conclude that none of the biological resurfacing techniques described achieved normal articular cartilage characteristics at 3 months, although the compliance of the repair site was closer to normal with synthetic than with periosteal grafting.

Animals↗
PubMed1993

The value of intraoperative isometry measurements in anterior cruciate ligament reconstruction: an in vivo correlation between substitute tension and length change.

With the objective to evaluate an "isometry" measurement in an anterior cruciate ligament (ACL) substitute, in vivo measurements were taken on 10 patients undergoing reconstruction due to chronic ACL deficiency. Change in intraarticular length of a 1.2-mm test ligament, measured with an isometer, was correlated to the tension created in the same test ligament after fixation, measured with a piezoelectric load cell. The knee was passively moved through the 0-100 degrees range with the patient under general anaesthesia. Good statistical and visual correlations between length change and tension curves were found in individual knees. A correlation between total length change and maximum tension, for all knees grouped, was also found. Individual knees showed large variation in ability of the tissue to absorb load, resulting in a wide range of N/mm ratios between length and tension. Three knees with an isolated ACL injury all showed the least length change, implying a better restoration of kinematics in the absence of associated injuries. In nine of 10 knees the length change pattern could be used to identify the location of the femoral drill channel, as determined on an intraoperative lateral projection of the knee. Intraoperative isometry measurement can be used to predict the tension pattern in the reconstructed knee, but not the magnitude of tension. It will be useful to the surgeon in avoiding an anterior femoral ligament insertion site, which might threaten the integrity of the graft by tension rise in flexion.

Adult↗
PubMed1993

Basal and thyrotropin-stimulated secretion rates of thyroglobulin from the human thyroid gland during surgery.

The secretion rates of thyroglobulin were measured under basal conditions and after exogenous and endogenous thyrotropin stimulation in 23 patients during surgery. In 11 patients with normal thyroid glands the median secretion rate of thyroglobulin was 0.7 pmol/24 h. Higher secretion rates were observed in 8 patients with nontoxic nodular goiter (median 22 pmol/24 h; p < 0.001) and in 4 patients with thyroid malignancy (median 2.2 pmol/24h; p < 0.05). Within 10 min after administration of highly purified human thyrotropin into the thyroid artery an increase of the secretion rates was observed in the 9 patients studied with normal thyroid glands and 5 patients with nontoxic nodular goiter. TRH administration to 5 patients induced a slight but nonsignificant increase of the secretion rate of thyroglobulin after 20 min. These results show that thyroglobulin is secreted directly into the thyroid venous blood. They also confirm that thyrotropin is an important regulator of the thyroglobulin secretion.

Adult↗
PubMed1993

A prospective comparison of Butel and PCA hip arthroplasty.

We compared two cementless femoral components, the 'isoelastic' Butel stem and the more rigid PCA design, in a randomised, prospective study of 56 patients with a mean follow-up of 4 years (2 to 5). Patients were matched in 28 pairs, and one of each pair was treated with each femoral component. The isoelastic stem gave fewer signs of stress shielding radiologically, but both the Harris hip score and the visual analogue pain scale showed significantly inferior results at the two-year and three-year follow-up. The overall failure rates for the femoral components were 43% for the Butel and 11% for the PCA. These results contrast with those of earlier experimental and clinical studies, in which isoelastic properties appeared to be advantageous. This review emphasises the importance of controlled studies before an altered or new design of prosthesis is released on to the market for general use.

Alloys↗
PubMed1993

Proteoglycan fragments in rabbit joint fluid correlated to arthrosis stage.

Proteoglycan fragment concentrations in joint fluid of rabbit knees with various degrees of secondary arthrosis after meniscal resection, meniscal substitution, and anterior cruciate ligament transection, were related to the gross appearance of the articular cartilage. Knees with normal cartilage were distinguishable by the concentration of proteoglycan fragments in joint fluid from knees with arthrosis. We found a correlation (r 0.61) between increasing arthrosis and increasing concentrations of proteoglycan fragments.

Animals↗
PubMed1993

Load and length changes in an artificial ligament substitute. 10 cases of anterior cruciate ligament reconstruction.

In 10 patients who had reconstruction of the anterior cruciate ligament, the load and length changes in an artificial ligament substitute were measured during passive knee motion. Using a special drill guide, the ligament was placed within +/- 2 mm of the normal anatomic center on the femur. With the femoral end fixed with a bicortical screw the ligament was preloaded to 40 N at the flexion angle with the shortest intraarticular ligament length, usually 45 degrees. The change in load was then registered from 90 degrees of flexion to full extension. In 2/10 cases loads of > 200 N were registered in full extension, but the mean load was 160 N. There was a higher loss of load during the first extension/flexion cycle than during the 4th cycle. The load change correlated to the length change, but the degree of length change could not predict the maximum load level. There was a large variation in load levels between different knees, even with similar ligament placements, but the least change in load and length was obtained by an anatomic placement. Isometer readings did not predict the load level in the ligament substitute, but could indicate the angle of flexion with minimum load. Therefore, the isometer can be used to control the placement of the attachment points for the substitute. After fixation, fiber settling and stretching the ligament, as well as adaptation of the tissues, will tend to reduce the load levels.

Adult↗
PubMed1993

[Cruciate ligament prostheses. Techniques, results and perspectives].

Artificial ligaments have been used as augmentation devices, scaffolds, ingrowth ligaments and even prostheses. The augmentation devices rely entirely on the autologous tissue for their function, whereas each of the other types functions more or less as a prosthesis. These devices can function only for a limited time and they are very sensitive to the implantation technique. Problems involve debris formation, synovitis and finally ligament rupture. There is also a loss of stability in the treated knee over the first 2-3 postoperative years. The clinical results obtained in various studies with the prosthetic devices are not satisfactory. The problem of reconstruction of a knee with ligamentous instability is far greater than that involved in replacing the ligament only.

Anterior Cruciate Ligament↗
PubMed1993

The effect of anterior cruciate ligament resection and immediate or delayed implantation of a meniscus prosthesis on knee joint biomechanics and cartilage. An experimental study in rabbits.

In a rabbit experiment with anterior cruciate ligament (ACL) resection, immediate substitution of the medial meniscus with a prosthesis was compared with delayed prosthetic implantation after a postmeniscectomy period of three weeks. The knees with a prosthetic implant were compared with their contralateral joints as well as to joints with an intact ACL and menisci. Anterior cruciate ligament resection alone led to disturbed biomechanics and cartilage degeneration. Anterior cruciate ligament resection in combination with meniscus resection increased cartilage degeneration and led to more inferior biomechanics. Ingrowth and stable fixation was less frequent when the prosthesis was inserted three weeks after meniscus resection than when inserted immediately. Furthermore, in knees with delayed prosthetic implantation, only minor improvement in terms of cartilage protection was shown when compared with knees with resection only. In contrast, knees with immediate meniscus replacement demonstrated similar joint stiffness and stress relaxation characteristics and similar cartilage protection effects as knees with a nonresected medial meniscus.

Animals↗
PubMed1993

The effects of an artificial meniscus substitute in a knee joint with a resected anterior cruciate ligament. An experimental study in rabbits.

A Dacron meniscus prosthesis was substituted for the medial meniscus in an anterior cruciate ligament (ACL) resected rabbit knee. At three months, the joints were evaluated biomechanically, with gross and histologic inspection. In a paired comparison with the contralateral knee, differences between ACL resection with intact, incised, or resected medial menisci were evaluated. Knees with intact menisci and ligaments served as controls. Because of cartilage destruction, soft-tissue hypertrophy, and increased anterior laxity, joint stiffness was less than normal in all ACL-resected knees. Ingrowth and stable fixation, especially of the posterior horns of the prostheses and the incised menisci, were rare. Almost all normal menisci had ruptured in the same area. Anterior cruciate ligament resection led to severe osteoarthrosis in both compartments, regardless of initial meniscal treatment. Knees with prostheses had the same incidence and severity of osteoarthrosis as knees with meniscus resection. Anterior cruciate ligament resection alone induced excessive osteoarthrosis and synovitis and diminished the effects of different meniscal treatments three months earlier.

Animals↗