Biomedical subjects

B Reider

Publications and source records attributed to B Reider.

8 recordsLinked to original sources

PubMed1990

Gait adaptations by patients who have a deficient anterior cruciate ligament.

Sixteen patients who had unilateral deficiency of the anterior cruciate ligament and ten healthy control subjects were analyzed during level walking, jogging, and ascending and descending stairs. Kinematic and kinetic findings for the right and left hips, knees, and ankles of all of the patients and control subjects were recorded during each activity. Substantial differences from normal function were observed for both limbs of the patients during level walking and during jogging. The magnitude of the maximum moment that tended to flex the knee was reduced the most (140 per cent) during level walking. It was reduced less (30 per cent) during jogging, it was not changed while the patient descended stairs, and it was slightly increased while he or she ascended stairs. The reduction in the magnitude of the flexion moment about the knee was interpreted as the patient's effort to reduce or avoid contraction of the quadriceps. Reduction of the flexion moment reduces any contraction of the quadriceps because there must be a mechanical balance between the external moment (due to body weight and the weight and inertia of the segment of the limb) that tends to flex the knee and an internal moment (generated by contraction of the quadriceps) that tends to extend the knee. This so-called quadriceps-avoidance gait was related to the angle of flexion of the knee when the maximum flexion moment occurred during each activity. This angle of flexion was 20 degrees during walking, 40 degrees during jogging, and approximately 60 degrees during stair-climbing.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1983

Treatment of knee joint instability secondary to rupture of the posterior cruciate ligament. Report of a new procedure.

For the past five years we have attempted to correct knee instability due to rupture of the posterior cruciate ligament with a procedure that employs a free graft of one-third of the patellar tendon with its tibial and patellar attachments. This procedure was done for chronic instability in thirty-three patients and was combined with primary repair of an acute mid-substance tear of the posterior cruciate ligament in fifteen patients. Moderate to severe articular injury of the medial femoral condyle was found at operation in 48 per cent of the patients with chronic injury. Seventy-one per cent of the patients for whom the interval between injury and ligament reconstruction was two to four years, and 90 per cent of those for whom the interval was more than four years, showed articular injury of the medial femoral condyle. Only 31 per cent of the patients, however, had preoperative radiographic findings that indicated femoral articular damage. Twenty-three of the twenty-five patients with a minimum follow-up of two years returned for evaluation. All of the ten patients who had had a repair and reconstruction of an acute ligament injury (whose average follow-up was forty-one months) had a static and functional result that was graded as good or excellent. Of the thirteen patients for whom surgery was done for chronic instability (whose average follow-up was thirty-one months), the over-all static and functional result was graded as good or excellent in eleven. These results indicate that the use of one-third of the patellar tendon for reconstruction in patients with acute mid-substance tears as well as in patients with symptomatic chronic instability of the posterior cruciate ligament is an effective procedure for achieving static and functional stability of the knee.

Adult↗

PubMed1979

The anterior cruciate ligament: a technique of repair and reconstruction.

Both primary repair and late substitution of anterior cruciate ligaments can be accomplished by intra-articular methods. This principle is to provide temporary struts that are initially avascular but can later undergo revascularization and metaplasia to form a new ligament. The graft does afford initial support, however. An understanding of anatomic principles, suture placement, freedom of graft from impingement, avoidance of acute angular deviation of the graft, solid static stability, anatomic attachment points, and blood supply, is absolutely essential for success in this field of surgery.

Fascia Lata↗

PubMed1977

Patella tracking.

Explore the source record for details and available documents.

Biomechanical Phenomena↗

PubMedDate not supplied

Diagnosis of cruciate ligament injury using single contrast arthrography.

To evaluate the accuracy of arthrography for assessing the status of the anterior cruciate ligament (ACL), 212 arthrograms from 212 knees in 205 consecutive patients undergoing single contrast arthrography and subsequent arthroscopy or arthrotomy were reviewed. Criteria for evaluation of the ACL included the clarity of its radiographic appearance as well as the anterior laxity of the knee as seen on manual stress views. Of the 111 knees having intact ACLs at surgery, 98 (88%) were evaluated correctly by arthrography. Of the 101 knees having a damaged ACL, 85 were read as torn or attenuated on the arthrogram. When the torn and attenuated ligaments were considered separately, accuracy was decreased. Of the 87 ligaments actually torn, 68 (78%) were read as torn and 9 (10%) as attenuated. Of the 14 actually attenuated, 5 (36%) were read as attenuated and 3 (21%) as torn. Of 114 arthrograms read as intact, 98 (86%) were correct. Of 77 arthrograms read as torn, 68 (88%), were correct. Of 21 arthrograms read as attenuated, 5 (24%) were correct. Of 114 torn medial menisci, 112 (98%) were correctly diagnosed, as were 38 (69%) of 55 torn lateral menisci. Sixteen of the 17 missed lateral meniscus tears were in knees with torn medial menisci. Single contrast arthrography is, therefore, highly accurate in distinguishing intact from damaged ACLs. The distinction between torn and attenuated ligaments, however, is not valuable.

Humans↗

PubMedDate not supplied

Analysis of the Müller anterolateral femorotibial ligament reconstruction using a computerized knee model.

Iliotibial tract tenodesis has been described by Müller as part of the surgical treatment for anterolateral rotatory instability in the ACL deficient knee. The aim of this study was to use a previously described and validated computer model of the knee to calculate the effectiveness of Müller's extraarticular anterolateral femorotibial ligament (ALFTL) graft as a substitute for the ACL or as an adjunct to an intraarticular ACL reconstruction in the ACL deficient knee. This effectiveness was tested by simulating the application of a torque sufficient to create 15 degrees of internal rotation or 5 mm of anterior displacement of the tibia on the femur at 0 degrees, 15 degrees, and 30 degrees of knee flexion. The effects of moving the graft's proximal fixation point 1 cm superior, inferior, and anterior to the current surgical attachment site were examined to determine the amount of permissible surgical error in graft placement. The model predicts that the ALFTL is a useful restraint to internal rotation when it is performed with or without an intraarticular ACL reconstruction. The ALFTL graft took up greater amounts of tension and became more effective at increasing angles of knee flexion. Placement of the ALFTL graft 1 cm anterior to the current surgical attachment site decreases the vector component that lies perpendicular to the long axis of the tibia and consequently reduces resistance to internal rotation. The ALFTL graft at any attachment site was ineffective in resisting pure anterior displacement between 0 degrees and 30 degrees.

Humans↗

PubMedDate not supplied

An in vitro study of the Müller anterolateral femorotibial ligament tenodesis in the anterior cruciate ligament deficient knee.

The biomechanical effectiveness of the Müller anterolateral femorotibial ligament (ALFTL) iliotibial band tenodesis on anterior stability and internal rotational stability of the ACL deficient knee was investigated in six cadaver knees. Anterior drawer and internal rotation of the tibia were measured at 15 degrees increments from 0 degrees to 90 degrees in response to 50 N of anteriorly applied tibial force and 3 Nm of internally applied internal torque, respectively, in the intact knee, the ACL excised knee, and following the ALFTL reconstruction. A strain gage was used to measure the resting graft tension and to measure strain in the graft during the load-displacement tests. The Müller ALFTL tenodesis failed to return normal anterior stability to the ACL deficient knee (P less than 0.05). The tenodesis did, however, reduce the anterior laxity of the ACL deficient knee from 30 degrees to 90 degrees of knee flexion (P less than 0.05). The tenodesis overconstrained internal tibial rotation of the ACL excised knee from 30 degrees to 90 degrees (P less than 0.05). Measurements of strain in the tenodesis supported the load-displacement findings that the tenodesis was most effective in constraining anterior drawer and internal tibial rotation from 30 degrees to 90 degrees of knee flexion.

Adult↗

PubMedDate not supplied

An in vitro study of an intraarticular and extraarticular reconstruction in the anterior cruciate ligament deficient knee.

The biomechanical effectiveness of an extraarticular ACL reconstruction, an intraarticular ACL reconstruction, and the combination of these on both anterior stability and internal rotational stability of the ACL deficient knee was investigated in six cadaver knees. The extraarticular reconstruction consisted of the Müller anterolateral femorotibial ligament iliotibial band tenodesis, and the intraarticular reconstruction used the middle third of the patellar tendon in the manner of Clancy. The extraarticular reconstruction was found to overconstrain internal tibial rotation of the ACL excised knee between 30 degrees and 90 degrees (P less than 0.05). While the isolated extraarticular reconstruction did not return normal anterior stability to the ACL deficient knee (P less than 0.05), it did significantly reduce the anterior laxity of the ACL deficient knee between 30 degrees and 90 degrees of knee flexion (P less than 0.05). For the combined reconstruction, the intraarticular procedure was performed and then only enough tension was applied to the extraarticular reconstruction to take up slack in the tenodesis without shifting the rotatory position of the tibia from that produced by the intraarticular procedure alone. Neither the intraarticular reconstruction nor the combined procedure resulted in any significant shifts from normal (P less than 0.05) in the rotatory position of the unloaded tibia; during loading neither resulted in rotational displacements significantly different from normal; and both of these procedures reduced the increased anterior laxity of the ACL deficient knee to a level not statistically different from normal. Because the extraarticular reconstruction shared the load when performed with the intraarticular reconstruction as part of a combined procedure, we concluded that it would be useful as an adjunctive procedure in appropriate clinical situations.

Adult↗