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Biomedical subjects

L Engebretsen

Publications and source records attributed to L Engebretsen.

At least 73 records · Page 4Linked to original sources
PubMed1990

Method for setting total graft force and load sharing in augmented ACL grafts.

The objective of this study was to develop a method for obtaining a controllable and reproducible immediate postoperative mechanical state in a knee with an anterior cruciate ligament (ACL) reconstruction. This method, called the force-setting technique, was demonstrated using a composite graft consisting of the middle third of the patellar tendon with bone blocks (PT) and the ligament augmentation device (LAD). The total graft force was set to match the force in the intact ACL at 30 degrees flexion with the knee under the same standardized external load, while at the same time the load sharing between the biologic and augmentation components was controlled. The total graft force was set to match the ACL force three separate times in each knee, with ratios of load sharing set at the following levels: 50% PT-50% LAD, 25% PT-75% LAD, and 75% PT-25% LAD. ACL, PT, LAD, and collateral forces were measured using buckle transducers, and three-dimensional knee motion was measured using an instrumented spatial linkage as 90 N anteriorly directed tibial loads were applied to eight specimens at 0 degree, 30 degrees, 60 degrees, and 90 degrees flexion with an intact ACL, an excised ACL, and the three load-sharing reconstruction states. The total graft force could be consistently set to within an average of 2% of the intact ACL force at 30 degrees flexion, and load sharing between the graft segments could be set to within an average of 5.1% of the desired ratio at 30 degrees.(ABSTRACT TRUNCATED AT 250 WORDS)

Cadaver↗
PubMed1990

Anterolateral rotatory instability of the knee. Cadaver study of extraarticular patellar-tendon transposition.

A cadaver knee-testing system was used to analyze the effect of an extraarticular reconstruction for anterolateral rotatory instability in which the lateral one third of the patellar tendon with a patellar bone block was transposed to the lateral femoral condyle. Ligament and reconstruction tendon forces were measured using buckle transducers, and joint motion was measured using an instrumented spatial linkage as 90 N anteriorly directed tibial loads were applied to seven knee specimens at 0 degree, 30 degrees, 60 degrees, and 90 degrees of flexion by a pneumatic load apparatus. This was done for each knee with first an intact, then an excised anterior cruciate ligament, and finally the extraarticular reconstruction. Forces in the transposed graft exhibited an isotonic pattern over the flexion range, unlike the intact anterior cruciate ligament, which was more highly loaded in extension than in flexion. The transposition of the patellar tendon led to external rotation of the tibia in both unloaded and anterior load conditions throughout flexion. Collateral ligament forces increased with anterior cruciate ligament excision, with the force in the medial ligament remaining higher than normal with the reconstruction, while the lateral forces became lower than normal.

Biomechanical Phenomena↗
PubMed1990

Short-term results of the nonoperated isolated anterior cruciate ligament tear.

A review of reports on nonoperative treatment of acute, isolated anterior cruciate ligament (ACL) tears shows a large variability in results. This may be caused by variations in study designs. To our knowledge, no prospective study on isolated ACL tears diagnosed through arthroscopy has been published. We are reporting the short-term results of a prospective study of 29 nonoperatively treated acute ACL injuries. All patients had a history of trauma, with contact sports resulting in 20 of 29 injuries. The mean age was 25 years. The mean follow-up was 33 months. Of the 29 patients, 11 required ligament reconstruction in the follow-up period because of considerable instabilities. Only two patients kept their activity level. All but two patients had a positive pivot shift. The reconstructed group was younger than the nonoperated group, had a higher preinjury level of activity both in sports and daily life, and in general had a desire to stay at the preinjury level. The nonreconstructed group had a lower preinjury activity level and was willing to reduce their postinjury level. When suggesting nonoperative treatment to a young patient with an isolated ACL tear, the surgeon should emphasize the importance of abandoning contact sports and obtaining good muscle strength. A young patient in a knee-demanding profession or insisting on continuing knee-demanding sports should have an early reconstruction carried out.

Adolescent↗
PubMed1989

[Treatment and rehabilitation of anterior cruciate ligament injuries in Norway. A comparison with the Anterior Cruciate Ligament Study Group].

The method of treatment for ruptures of the anterior cruciate ligament range from nonoperative treatment through direct repair to complicated augmentation. The Anterior Cruciate Ligament (ACL) Study Group, consisting of orthopaedic surgeons from USA, Canada, Australia, Sweden, Austria and Switzerland, summarized its thoughts on treatment and rehabilitation in a recent paper. A survey has been carried out on Norwegian treatment practice and compared with the practice of the Anterior Cruciate Ligament Study Group. This paper describes the difference in treatment between the two groups of surgeons and reviews the methods of rehabilitation used for acute tears of the Anterior Cruciate Ligament Study Group. The majority of Norwegian surgeons in this study use primary repair with no augmentation, while surgeons in the Anterior Cruciate Ligament Study Group use augmentation methods allowing early mobilization and return to preinjury activities. 88% of the Norwegian surgeons prescribed a cast for six weeks after surgery, while only 15% of the surgeons in the Anterior Cruciate Ligament Study Group prescribe immobilization for more than four weeks. In the rehabilitation protocol the Anterior Cruciate Ligament Study Group emphasizes strength training of the hamstring in order to protect the Anterior Cruciate Ligament, at the same time preventing dynamic exercises of the quadriceps for the last 30 degrees of extension so as to prevent strain on the Anterior Cruciate Ligament. This policy was shared by less than 50% of the Norwegian surgeons.

Humans↗
PubMed1989

Knee mechanics after repair of the anterior cruciate ligament. A cadaver study of ligament augmentation.

An experimental knee-testing system was used to investigate the immediate postoperative mechanical state in knees with nonaugmented and augmented repairs of the anterior cruciate ligament. Ligament, repair tissue, and augmentation forces were measured using buckle transducers, and joint motion was measured using an instrumented spatial linkage during the application of 90 N anteriorly-directed tibial loads to seven fresh knee specimens at 0-90 degrees of flexion. Force and motion data were collected from each knee with an intact and excised anterior cruciate ligament, and after performing (1) a nonaugmented repair and an augmented repair using the Ligament Augmentation Device (3M Company) placed either (2) anatomically through the lateral femoral condyle or (3) in the over-the-top position. The forces in the nonaugmented repair and the repair with the augmentation in the two positions were greater than the forces in the intact anterior cruciate ligament with the knee under the same anterior loads; this difference from normal was not significant with the over-the-top augmentation. With the augmentation anatomically placed, the load sharing did not reduce the force in the repair tissue as compared with the nonaugmented case. The over-the-top augmentation, on the other hand, lowered the repair tissue forces at extension while avoiding high repair tissue forces in flexion. The tibia was consistently in an externally rotated configuration compared with normal in both the unloaded and anterior load states with all three repair procedures.

Biomechanical Phenomena↗
PubMed1989

Advancement of the tibial tuberosity for patellar pain. A 5-year follow-up.

During the period 1978-1984, 38 patients aged 23-55 years were treated for patellofemoral pain by the Maquet procedure. The mean postoperative observation time was 5(3-9) years. Thirty-three of the 38 patients were available for follow-up including functional and activity scoring, clinical examination, and Cybex II dynamometer muscle-strength measurement. Ten patients improved, 17 were unchanged, and 6 were worse. Characteristic for the improved group was Grades III and IV chondromalacia - mainly involving the lateral facet - whereas the group with no improvement or deterioration exhibited a low-grade chondromalacia, chiefly affecting the medial patellar facet.

Adult↗
PubMed1989

Primary suture of the anterior cruciate ligament. A 6-year follow-up of 74 cases.

Seventy-four consecutive patients were reviewed 6 (3-9) years after primary suture according to Palmer of a fresh rupture of the anterior cruciate ligament. Three fourths had excellent or good function as evaluated by the Lysholm score. The pivot shift test was trace-positive in one fifth and 2+ or 3+ in one quarter, and the Lachman test was 2+ or higher in one third. Tibial anterior instability was present in 23 knees. Radiographically, 15 knees had signs of arthrosis, 4 of which severe. Our 0.25 failure rate suggests that other procedures should be considered in the treatment of acute rupture of the anterior cruciate ligament.

Adolescent↗
PubMed1989

Early postoperative weight-bearing and muscle activity in patients who have a fracture of the ankle.

Fifty-six patients who had a displaced fracture of the ankle necessitating surgical fixation were randomly assigned to one of three postoperative treatment regimens: no plaster cast or weight-bearing, and active exercises of the ankle; a non-weight-bearing plaster cast; or a plaster walking cast for the first six postoperative weeks. At follow-up with a duration of as much as two years, there were no consistent differences in the clinical results between the three groups. The time lost from work and the proportion of excellent and good clinical results were also uninfluenced by the postoperative regimen. No adverse effects could be detected as a result of the patient's having walked before the syndesmosis screw had been removed. It was concluded that none of the three postoperative regimens has any advantage over the others in a patient who has a stable osteosynthesis of a fracture of the ankle.

Adult↗
PubMed1988

Poor results of anterior cruciate ligament repair in adolescence.

Eight adolescents were followed 3-8 years after primary suture of a substance rupture of the anterior cruciate ligament. Only 3 patients had good function, and 5 were unstable. We conclude that the Palmer-Marshall technique should not be used in children and adolescents.

Adolescent↗
PubMedDate not supplied

Risk of injury during alpine and telemark skiing and snowboarding. The equipment-specific distance-correlated injury index.

Estimation of injury risk in alpine sports is difficult. We present a new method of calculating an injury index related to the distance traveled on ski or snowboard. The distance-correlated injury index equals the number of injuries per 100,000 km traveled distance. This injury index can also be correlated to the type of equipment used. The equipment-specific distance-correlated injury index is the same as the distance-correlated injury index, but it is sport-specific. We found the distance-correlated injury index for alpine skiing to be 3.9 (95% Cl = 2.8 to 5.4); for snowboarding, 13.5 (95% Cl = 8.3 to 22.0); and for telemark skiing, 3.0 (95% Cl = 1.0 to 9.4), suggesting a three- to four-times higher incidence of injuries requiring hospital treatment among snowboarders than among alpine and telemark skiers.

Athletic Injuries↗
PubMedDate not supplied

The efficacy of wrist protectors in preventing snowboarding injuries.

Injuries of the wrist are common among snowboarders and in-line skaters. Wrist protectors have been developed to protect against injury. Some studies support the use of such wrist protection, but others emphasize the fact that wrist protectors may transfer the injury to other locations in the forearm. We conducted a prospective, randomized, clinical study of 5,029 snowboarders, 2,515 in a braced group and 2,514 in a control group. The primary endpoint was fracture or sprain of the wrist with loss of range of motion and pain of at least a 3-day duration. Concomitant injuries were also recorded. Eight wrist injuries occurred in the braced group and 29 occurred in the control group. This was a significant difference. Beginners (first 5 days on a snowboard) and snowboarders with rented equipment were more prone to injury than others. No injuries could be related to the use of the wrist brace. We conclude that wrist braces are effective in protecting snowboarders against wrist injury. Beginners are a high-risk group.

Adolescent↗
PubMedDate not supplied

The effect of an iliotibial tenodesis on intraarticular graft forces and knee joint motion.

Lateral extraarticular reconstructions are used as isolated procedures in knees with moderate rotatory instability and as "backups" in knees requiring primary repair or intraarticular reconstruction for major rotatory instability. We used an experimental knee testing system to analyze the immediate postoperative mechanical effect of an iliotibial band tenodesis on an intraarticular reconstruction of the ACL in fresh cadaver knees using a composite graft consisting of a bone-patellar tendonbone segment augmented with the Kennedy Ligament Augmentation Device (LAD, 3M Co., St. Paul, MN). The intraarticular graft was standardized by using a forcesetting technique. Ligament and graft forces were measured using buckle transducers, and joint motion was measured using an instrumented spatial linkage as 90 N anteriorly directed tibial loads were applied to seven fresh knee specimens at 0 degrees, 30 degrees, 60 degrees, and 90 degrees of flexion. The following knee states were tested in each specimen: intact ACL, excised ACL, intraarticular reconstruction, intraarticular reconstruction with the tenodesis added, and tenodesis with the intraarticular reconstruction added. Adding the iliotibial band tenodesis to an existing standardized intraarticular reconstruction significantly decreased the force in the ACL composite graft by an average of 43%. When the standardized intraarticular reconstruction was added to an existing tenodesis, the graft forces were an average of 15% below the level of when the reconstruction was performed alone. The force in the tenodesis was significantly less than the composite graft force at extension; however, the differences between the tenodesis and total graft force were not significant from 30 degrees to 90 degrees of flexion.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomechanical Phenomena↗
PubMedDate not supplied

A prospective, randomized study of three surgical techniques for treatment of acute ruptures of the anterior cruciate ligament.

Treatment of ACL tears is controversial. Recent reports on nonoperative treatment have shown poor results. Results after primary repair have deteriorated with time, leading to augmentation procedures that seem to have improved the results. However, there have been few prospective, randomized studies in this field. Our goal was to compare primary repair with a bone-patellar tendon-bone augmentation method and with a new method using the Kennedy Ligament Augmentation Device. One hundred fifty patients aged 16 to 50, all of whom had acute ACL tears, were randomized with the closed envelope method to one of three groups treated with open surgical methods. Fifty patients were treated with primary repair, 50 patients with patellar tendon augmentation, and 50 patients were augmented with the Kennedy Ligament Augmentation Device. All patients were operated on within 10 days of injury. The rehabilitation protocol was identical, consisting of a long leg cast for 2 weeks, followed by a brace with no weight-bearing and limited motion for 6 weeks. The patients were followed prospectively by one surgeon (LE) using the Lysholm functional score, Tegner activity level score, clinical evaluation and KT-1000 arthrometer at 6 months, 1, and 2 years. Three patients were lost to followup. There was no age or activity level difference between the groups. Sport activities led to 85% of the injuries, with skiing, soccer, and European handball representing 80% of injuries. All three groups reduced their activity level the 1st year. The repair group remained at the same level after 2 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗