Biomedical subjects

J Gillquist

Publications and source records attributed to J Gillquist.

At least 55 records · Page 3Linked to original sources

PubMed1992

Instability after anterior cruciate ligament rupture. Measurements of sagittal laxity compared in 11 cases.

Manual tests and 2 external devices were used together with roentgen stereophotogrammetry (RSA) and an active weight-bearing radiographic method to measure the sagittal laxity in 11 knees with anterior-cruciate-ligament rupture. In 5 knees no ligament surgery had been performed (unstable knees) and in 6 knees a reconstruction had been performed one year before the examination (stable knees). There were positive correlations between all methods, including the manual tests when all knees, both stable and unstable, were analyzed together. However, the mean values of the total displacement differed between the methods, especially when comparing the weight-bearing radiographs with the three other methods. Some knees with substantial displacement during passive loading did not show any displacement when weight bearing; the measurements thus depended on both the ligamentous laxity and the patient's neuromuscular control of the joint. When the stable knees were analyzed separately, higher mean values were recorded with the external devices than with RSA using 180 N load. This could be explained by an error from soft tissue deformation which added to the skeletal displacement when the external devices were used.

Adolescent↗

PubMed1992

The long-term course of various meniscal treatments in anterior cruciate ligament deficient knees.

One hundred thirty-five patients were reviewed six to 16 years after anterior cruciate ligament repair or reconstruction. At follow-up evaluation, 60% of the patients demonstrated significant residual laxity on objective testing. Thirty percent of the patients reduced activity levels because of instability. Degenerative arthritis was noted to be more frequent in those patients who had been treated with total open meniscectomy than in those treated with arthroscopic partial meniscectomy, and it was more severe than in patients with intact menisci. Continued participation in high-stress sporting activities generally led to a high rate of further injuries, reoperations, and progression of osteoarthrosis.

Adolescent↗

PubMed1992

The strain distribution in the upper tibia after insertion of two different unicompartmental prostheses.

The strain distribution in the proximal tibia in seven human autopsy specimens was investigated with strain-gauge rosettes attached on the medial proximal aspect of the tibia. The strains measured were about the same on the proximal bone and on the bone in the metaphysis. The direction of the minimal principal strain (compression) was about 45 degrees counterclockwise (left knee). After insertion of a unicompartmental prosthesis medially, a non-constrained prosthesis with a loose meniscus-bearing and a constrained prosthesis, the tensile strain was about four times higher in the most anteromedial gauge. No significant differences were found between prostheses. Tests were also performed with the two prostheses inserted into three plastic models. The constrained prosthesis was more sensitive to outward rotation of tibia versus femur, which made the femoral component climb up the slope of the tibial component and caused a marked change in the strain distribution compared to loading in the neutral position. With the other prosthesis, a malpositioning of the tibial component medially caused the meniscus bearing to lie close to the medial rim of the tibial component. An external rotation of tibia then made the system constrained and dramatically changes the strain distribution.

Biomechanical Phenomena↗

PubMed1991

Intercondylar notch measurements with special reference to anterior cruciate ligament surgery.

The femoral intercondylar notch width was measured in 93 patients with chronic anterior cruciate ligament (ACL) insufficiency (Group 1), in 62 patients with an acute tear of the ACL (Group 2), and in 38 fresh anatomic specimen knees (Group 3). In six of the specimen knees, further anatomic studies of the intercondylar notch were performed after tissue removal. The average intercondylar distance was 16.1 mm in Group 1, 18.1 mm in Group 2, and 20.4 mm in Group 3. All differences were highly significant. The intercondylar notch was wider in the posterior part and had no crossing bony ridges but had generally concave walls, which provided a functional shelf for the ACL to insert on the lateral side. Significant osteophyte formation and stenosis of the anterior outlet of the intercondylar notch occur early in the ACL-deficient knee. A narrow anterior outlet of the intercondylar notch without osteophytes was also found in knees with an acute ACL rupture. At reconstruction of the ACL, notchplasty should be performed concomitantly.

Anterior Cruciate Ligament↗

PubMed1991

Knee function after surgical or nonsurgical treatment of acute rupture of the anterior cruciate ligament: a randomized study with a long-term follow-up period.

One hundred fifty-six patients with a total rupture of the anterior cruciate ligament (ACL) were reexamined 41 to 80 months after injury. They were randomized to three treatment groups: (1) repair and augmentation of the ACL with an iliotibial strip, (2) repair without augmentation, and (3) nonsurgical ACL treatment. Associated injuries of menisci and other ligaments were treated in the same way for the three groups. Two-thirds of the patients in the nonsurgically treated group complained of instability and 17% had had a subsequent reconstruction of the ACL at the follow-up examination. The group treated with an augmented repair had a less abnormal laxity measured by a laxity-testing device. Sixty-three percent returned to competitive sports, as compared with 27% in the nonsurgical group and 32% in the only repair group. Relative strength of the quadriceps and hamstrings muscles were similar for all groups. The augmented-repair group had better hop tests, reflecting a superior stability, whereas running was not affected by treatment but was correlated with the activity level.

Adolescent↗

PubMed1991

Rehabilitation after high tibial osteotomy and unicompartmental arthroplasty. A comparative study.

Ten patients with medial gonarthrosis treated by unicompartmental arthroplasty were matched with ten patients who had high tibial osteotomy; their courses of rehabilitation were evaluated. All patients regained motion without problems, with no difference between the groups. Muscle torque was measured by a Cybex II dynamometer. The results six months postoperatively were better in the patients treated by unicompartmental arthroplasty than they were 12 months postoperatively in the patients treated by high tibial osteotomy. In the prosthesis group there was an increase in the maximal gait velocity and the duration of single support. In the osteotomy group there was no significant change. This difference in the results of rehabilitation constitutes an argument for arthroplasty in aged patients.

Aged↗

PubMed1990

High tibial osteotomy for medial osteoarthritis of the knee. A 5 to 7 and 11 year follow-up.

On three occasions we have reviewed a series of knees after high tibial osteotomy for osteoarthritis: 99 were reviewed at one to two years; 81 at a mean of 5.7 years; and 65 at a mean of 11.9 years. At one to two years and at 5.7 years over 50% were good and over 75% acceptable. At 11.9 years, 43% were good and 60% acceptable. We determined the mechanical axis through the knee in maximum varus and maximum valgus; significantly better results were found if a mean angulation of 3 degrees to 7 degrees of valgus had been achieved at operation. We also measured intercondylar distances under varus and valgus stress, and found no significant lateral compartment narrowing. The best results were seen in knees with pre-operative grade I or grade II osteoarthritis and valgus deviation after osteotomy.

Adult↗

PubMed1990

Load tolerance, security, and failure modes of fixation devices for synthetic knee ligaments.

One weak link in synthetic ligament reconstruction of the knee is the fixation device-ligament-bone interface. In this study, a laboratory model using bovine calf bone was designed to evaluate six different fixation devices combined with either an unlooped ligament in different configurations or a looped ligament. Results are expressed in terms of maximum load to failure, elongation at the site of fixation, stiffness of fixation prior to failure, and mode of failure. When failure of the test model occurred, it was always at the ligament--fixation device interface, the fixation device--bone interface, or a combination of the two. Elongation was recorded in all modes of fixation. The most secure fixation was obtained with a cortical screw and a looped ligament, the strength and predictability being mainly dependent on bone quality. The least secure and least predictable fixation was obtained with a prototype called bucket wedge. A barbed ligament staple and an unlooped ligament also had low predictability and considerably less strength than the screw fixation but showed less sensitivity to alterations in bone quality.

Animals↗

PubMed1990

Instrumented testing for evaluation of sagittal knee laxity.

Seventy-one patients with untreated ruptures of the anterior cruciate ligament of at least four years' duration had their knee laxity examined with a laxity testing device. Twenty of the 71 patients were tested by two examiners independently. Another 30 patients without previous knee injury were chosen as a reference group and tested. Patients with anterior cruciate-deficient knees had significantly increased anterior and total laxity. If the testing procedure was altered, the laxity changed. Thus, an increase of knee flexion from 15 degrees to 25 degrees resulted in an increased anterior laxity. Changes in the amount and placement of the tibial load also affected laxity. Inter-examiner reproducibility was high if a standardized testing procedure was followed. Sensitivity was 92% if the difference in total laxity between involved and uninvolved knees was determined with a high tibial load (180 N), whereas specificity was 70%. Therefore, the laxity tester has disadvantages as a diagnostic tool, but it is still valuable for evaluation of anterior cruciate ligament ruptures and their treatment.

Adolescent↗

PubMed1989

Dacron augmentation of a free patellar tendon graft: a biomechanical study.

The mechanical characteristics of a knitted 8-mm Dacron tube used as augmentation for patellar tendon strips was analyzed and compared with ligament augmentation device (LAD) tendon strips. The failure load was found to be the same (approximately 320 N) for both types of ligament augmentations. The typical failure mode in the Dacron augmentations was rupture of the Dacron tube proximal to the proximal bone fragment. The LAD augmentations failed at the suture line. The Dacron composite was stiffer than the LAD composite at low loads, but both composites became stiffer after two load cycles to 40 N with stress relaxation. At the end of the second stress relaxation cycle, the remaining load was significantly higher for the Dacron composite. During the second 2-min stress relaxation period, the Dacron composite lost 23% and the LAD composite lost 28% of the applied load. The stiffness and the elongation to failure was the same for both composites. The study showed that the Dacron tube may have possibilities similar to the LAD for use as an augmentation device.

Humans↗

PubMed1989

Early arthroscopic evaluation of acute repair of the anterior cruciate ligament.

Follow-up arthroscopy was performed in 71 patients who had undergone primary repair of an acute rupture of the anterior cruciate ligament (ACL) after 6-19 months. An augmented repair was done on 61 patients and 10 patients had a nonaugmented repair. Based on the arthroscopic findings, the ACL repair was classified into three categories. Four years after the injury a clinical reexamination, including a laxity test using instrumentation and a standard knee-function test, was done on 66 patients. Arthroscopy revealed that 64 of the 71 patients (90%) had a defined ACL repair, although the repair was elongated in 37 patients. Seven patients with a nonfunctioning ACL repair had inferior knee function after 4 years. Arthroscopy also showed superficial cartilage lesions in 24 patients and meniscal pathology in 6 patients. Two patients with more advanced chondral lesions had inferior knee function. Treatment of meniscal injuries did not affect the long-term results.

Adult↗

PubMed1989

Removal of bone staples: a potential problem in revision surgery after ligament reconstruction.

Two cases are presented in which an attempt to remove the staples used to fix an artificial ligament caused the front of the tibia to break. A mechanical study was performed to measure the force required to extract staples from bone cement, as well as from calf bone with predrilled holes. Using an extraction tool, it was possible to generate an average maximum force of 500 N by hand. At that load, all staples remained firmly anchored in cement and bone. The staples were impossible to remove even when the serrations in the staple legs were reduced by 75%. Accordingly, special care is necessary to avoid complications with staple removal.

Adult↗

PubMed1989

Failure of a bovine xenograft for reconstruction of the anterior cruciate ligament.

Fourteen patients with gross anterior instability had the anterior cruciate ligament reconstructed with a bovine xenograft. Major problems with swelling, pain, and synovitis were encountered in 13 patients, of whom 3 developed a synovial fistula. Histologic evidence for allergic reactions was found in 3 patients. Revisional surgery had to be performed in 10 patients because of substantial problems or rupture of the graft. At 3 years, there was only one possibly functioning graft. The 3 nonrevised patients were unstable at clinical examination. This type of reconstruction cannot be recommended for clinical use.

Adolescent↗

PubMed1989

Air inclusion in bone cement. Importance of the mixing technique.

The amount of air inclusion in bone cement (Simplex P) expressed as density and porosity was analyzed for five different mixing conditions: manual, mechanical, centrifuged manual, centrifuged mechanical, and mechanical in combination with vacuum. Mechanical mixing resulted in a cement of less porosity and increased density. Centrifugation did not further improve the cement. Mechanical mixing in combination with vacuum was superior to the other techniques in density and porosity.

Air↗

PubMed1989

Non-operative treatment of meniscal tears.

In a retrospective review of the results of 3,612 arthroscopic procedures that were performed for the treatment of an acute or a chronic meniscal lesion, with or without an associated ligamentous lesion, we identified eighty meniscal tears (in seventy-five patients) that had been assumed to be stable. Seventy were vertical longitudinal tears and ten were vertical radial tears. The seventy longitudinal tears included fifty-two lateral and eighteen medial meniscal lesions. All of the radial tears were in the lateral meniscus. Of the seventy-five patients, fifty-two had been followed for two to ten years. At the time of follow-up, only six of these fifty-two patients had needed additional intervention because of symptoms that were related to the meniscal tear. Four of them had the intervention after a sports-related traumatic extension of a stable tear, and two, because persistent symptoms were caused by the original meniscal lesion. A repeat arthroscopy was performed on thirty-two patients (twenty-six of whom had a longitudinal tear and six of whom had a radial tear), at an average of twenty-six months after the original arthroscopy. Seventeen of the twenty-six longitudinal tears had completely healed. Five of the six radial tears had no evidence of healing and one had extended. Neither ligamentous laxity nor a meniscal tear that was chronic at the time when it was discovered appeared to preclude healing of the stable longitudinal tears. No localized degenerative changes in the adjacent articular cartilage were found in association with any of the stable vertical longitudinal or radial meniscal lesions. Excluding the six patients who had had additional surgical treatment, none of the fifty-two patients who filled out a questionnaire reported that they had symptoms of a meniscal lesion, and none of the forty-two patients who were re-examined two years or more after the operation had signs of a meniscal lesion. Stable vertical longitudinal tears, which tend to occur in the peripheral vascular portions of the menisci, have great potential for healing. The tear should be left alone unless it is the only abnormality that is found and it is causing symptoms that warrant treatment. Stable radial tears, which tend to occur in the avascular inner one-third of the meniscus, have little potential for healing. Whether it is best to leave these lesions alone or to fashion an intact rim by contouring the meniscus was not established by this study.

Adolescent↗

PubMed1989

Surgical or non-surgical treatment of acute rupture of the anterior cruciate ligament. A randomized study with long-term follow-up.

One hundred and eleven consecutive patients who had acute injuries to the knee that included rupture of the anterior cruciate ligament, as shown by physical examination with the patient under anesthesia and by diagnostic arthroscopy, were randomized to three treatment groups: simple repair of all injured structures, repair of all injured structures and augmentation of the anterior cruciate ligament with a strip of the iliotibial band, and repair of all injured structures except the anterior cruciate ligament. In all other respects, the knees were treated in an identical fashion. Of the 111 patients, 107 were re-examined forty-five months or more after operation. At the most recent follow-up, the knees that had been treated by repair and augmentation of the anterior cruciate ligament were significantly more stable and had had significantly fewer subsequent meniscal tears. Sufficient instability to necessitate late reconstruction was also less frequent in the patients who had had an augmented repair. These patients had better function of the knee and a higher level of activity than the patients in the other two groups. Sixty-four per cent of these patients who had a rupture of the anterior cruciate also had a meniscal tear, and primary care was indicated for more than 50 per cent of the tears. Therefore, we believe that early arthroscopic examination is essential for patients who have an acute rupture of the anterior cruciate ligament.

Adolescent↗

PubMed1988

Arthroscopic reconstruction of the anterior cruciate ligament.

Arthroscopic reconstruction of the anterior cruciate ligament was compared with reconstruction through a miniarthrotomy. The operation time was significantly longer with arthroscopy, but the Lysholm scores and activity levels were the same in both groups before and 1 year after the operation. There was no difference in quadriceps torque between the groups before surgery and at 3, 6, and 12 months postoperatively. The measured stability in 20 degrees of knee flexion was similar in both groups before, immediately after, and 3, 6, and 12 months after surgery. A slow increase in the laxity was noted. One of 20 ligaments ruptured in the arthrotomy group due to a new trauma. In the arthroscopy group, there was one rupture due to abrasion. During the follow-up, two cases in the arthroscopy group had synovitis, in one case leading to removal of the prosthesis. There seems to be no major benefit from arthroscopic reconstruction in terms of rehabilitation. The miniarthrotomy is preferred since the notch plasty is easier to perform adequately during it than during arthroscopy.

Adult↗

PubMed1988

Discoid lateral menisci: a report of 29 cases.

Of 7,056 knee arthroscopies performed during the period September 1979-November 1986, 30 patients had discoid menisci, one medially and 29 laterally. The frequency of discoid lateral menisci appears to be lower in Sweden than in North America, Scotland, and Japan. Our policy, to do a meniscectomy only when the discoid meniscus is thought to play a role in the symptoms, but leave it intact when an incidental finding, seems to give good results. Nine of the 29 patients studied had trauma as an initiating factor, but of those 10 patients whose discoid lateral menisci were thought to cause the symptoms, only one had trauma as an initiating factor. Theories of the cause of discoid menisci are discussed, as well as recommended treatment.

Adult↗