An experimental study on the replacement of the anterior cruciate ligament of the rabbit''s knee using an augmented substitute

This study was designed to test the putative role of plasma cholecystokinin (CCK) in eating behaviour by examining the relationships between bioassayed plasma CCK concentrations and rated sensations of satiety and hunger following the ingestion of an appetizing nutrient-dense meal and between plasma profiles of CCK and scintigraphically determined gastric emptying in nine healthy male volunteers. Mean plasma CCK levels from the whole group showed a significant negative correlation with mean hunger ratings (r = -0.64) and a positive correlation with fullness (r = +0.68). However, there was considerable interindividual variation and negative correlations with hunger were only seen in three out of nine subjects and positive correlations with fullness in four out of nine subjects. In contrast, there was a strong relationship between the plasma CCK produced over the first 2 h after the meal and the half time for gastric emptying of the meal (r = -0.81). These data do not support a direct role for circulating levels of CCK in the control of hunger and satiety following a meal. Instead, the strong correlation with gastric emptying is compatible with release of CCK in response to nutrient delivery into the small intestine.     

Value of posterior cruciate ligament index in the diagnosis of anterior cruciate ligament injuries

Several EF-hand recoverin mutants were obtained and their abilities to bind to photoreceptor membranes and to inhibit rhodopsin kinase were determined. The mutants with the 'spoiled' 2nd, 3rd or (2nd+3rd) EF-hand structures did not act upon the kinase activity in the microM range of Ca2+ concentrations. Mutations of the 4th EF hand, which 'repaired' its Ca2+-binding activity, resulted in recoverin with three 'working' Ca2+-binding sites. The latter mutant inhibited rhodopsin kinase even more effectively than the wild-type recoverin, containing two working Ca2+-binding structures.     

Reconstruction of anterior cruciate ligament using the doubled tendon graft technique: an experimental study in rabbits

BACKGROUND: Mepartricin, a semisynthetic polyene derivative with a favorable effect on urethro-prostatic function, was clinically evaluated, adopting the diagnostic and research criteria recommended by the First International Consultation on BPH. METHODS: A multicenter, randomized, double-blind, parallel-group study compared mepartricin 40 mg/daily to placebo in the treatment of 196 patients with newly diagnosed BPH and mild-to-moderate symptomatology. International Prostate Symptom Score (I-PSS), quality of life (QoL) index and maximum urinary flow-rate (Qmax) were determined every 4 weeks for 6 months; postvoiding volume, prostate volume, and prostate-specific antigen (PSA) were assessed after 3 and 6 months of therapy. RESULTS: Mepartricin was shown to determine a statistically significant improvement over placebo in I-PSS and QoL index from month 2 onwards, and a significant linear increase in Qmax over the study period. At month 6, the improvement in the mepartricin and placebo groups in I-PSS, QoL index, and Qmax was 6.3 (standard error (SE) 0.51) and 4.2 (SE 0.60) points (P = 0.003), 0.99 (SE 0.14) and 0.62 (SE 0.12) points (P = 0.036), and 2.7 (SE 0.46) and 1.2 (SE 0.46) ml/sec (P = 0.051), respectively. No significant differences were noted in postvoiding residual volume, prostate volume, or PSA. Mepartricin tolerability was good, showing no adverse events on sexual function. CONCLUSIONS: Mepartricin proved to be an effective treatment of benign prostatic hyperplasia, determining an improvement in symptoms, quality of life, and peak urinary flow.     

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.     

The use of cold therapy after anterior cruciate ligament reconstruction. A prospective, randomized study and literature review

We performed a randomized, prospective study to assess the effectiveness of postoperative cold therapy in patients who had anterior cruciate ligament reconstructions. Drain output, length of hospital stay, range of motion, and use of pain medication were all assessed. Patients were randomized into one of four groups after surgery. Group 1 patients had a cooling pad applied to the knee postoperatively and set at a temperature of 40 degrees to 50 degrees F, Group 2 had the cooling pad set at 70 degrees to 80 degrees F, Group 3 received ice packs, and Group 4 received no cold therapy of any kind. The skin temperatures in Groups 1 and 3 were significantly lower than the skin temperatures in Groups 2 and 4 (P < 0.001). The length of hospital stay, range of motion at discharge, use of oral and intramuscular pain medicine, and drain output were not significantly different between groups. No complications related to the type of cold therapy were seen in any group. Thus, both ice packs and cooling pads significantly decreased knee temperature, but we found no objective benefits in the early postoperative course due to this decrease in temperature.     

The anterior cruciate ligament in controlling axial rotation. An evaluation of its effect

Changes in axial tibial rotation after anterior cruciate ligament sectioning were evaluated in 14 fresh human knee joints. Simulation of vertical stance in a quadriceps-stabilized knee was performed. Internal and external rotational torques were applied before and after anterior cruciate ligament sectioning. Pivot shift tests were done in the intact and anterior cruciate ligament sectioned knee. Results of pivot shift tests were all negative before sectioning and positive after isolated sectioning. No significant change in axial rotation occurred between the intact and sectioned knee for external rotation (P = 0.24) or internal rotation (P = 0.12). Presence of a load at the femoral housing in both the intact and ligament-sectioned knees caused a significant change in external rotation (P < 0.0001). No significant change was noted in internal rotation between loaded and unloaded states (P = 0.70). Total tibial rotation in the intact knee was noted to vary between 31 degrees at 0 degree of flexion and 42 degrees at 60 degrees of flexion. These results suggest that the anterior cruciate ligament does not play a significant role in limiting axial rotation and that rotational instability is not a major factor after isolated anterior cruciate ligament rupture.     

Prosthetic replacement of the anterior cruciate ligament in dogs

Prosthetic cruciate ligaments are now used clinically. Long-term results are not yet available and for that reason an attempt has been made to reproduce the clnical situation in dogs. Post-traumatic osteoarthritis was inevitably noted following simple excision of the anterior cruciate ligament in a control group of 10 animals. Different prosthetic materials were used and their breaking point was compared with that of normal anterior cruciate ligaments. The longest follow-up period was 6 months. Although some animals had no clinically demonstrable instability, at autopsy all prosthetic ligaments were noted to have failed. The degree of post-traumatic osteoarthritis was directly related to the duration of follow-up. The causes of failure of the prosthetic ligament do not appear to be related to the method of anchorage to bone but rather to the type of prosthetic material used. Although the tensile strength may occasionally have been sufficient, the materials did not have the required elastic characteristics to meet the physiologic demands of a normal cruciate ligament.     

The relationship between anterior cruciate ligament reconstruction tibial tunnel location and the anterior aspect of the posterior cruciate ligament insertion

OBJECTIVE: To assess the outcome of 31 patients treated in a day and semi-residential psychotherapy setting. METHOD: Patients had moderate to severe personality difficulties and were referred when current therapy was insufficient or because of the severity of their problems. Eighty-one percent had a Cluster C and 19% a Cluster B (Borderline) Personality Disorder diagnosis (DSM-III-R). Therapy was psychodynamically and feministin-formed and included a sociopolitical dimension. Rating scales used were the Symptom Checklist 90, Goal Attainment Scale, Global Assessment Scale and measures of health resource usage, which were completed pre-treatment, post-treatment and at 4-, 12- and 24-month follow-up. RESULTS: Mean duration of therapy was 4 months (68 therapy days). All clinical rating scales demonstrated marked improvements following treatment (p < 0.0001) which were sustained at 2-year follow-up. There were also improvements of health resource usage. CONCLUSIONS: The results document the clinical efficacy of psychotherapy in this setting, provide support for the philosophy of practice, and suggest that psychotherapy outcome can be evaluated at reasonable financial cost in many settings.     

Isolated tear of the anterior cruciate ligament: 5-year follow-up study

During the period 1967 to 1971, 64 cadets at the United States Military Academy, West Point, New York, had surgical repair for isolated tear of the anterior cruciate ligament. In a 5-year follow-up study to determine the functional impairment, present disability, and reinjury to the knee, 32 of the 64 patients were located and evaluated by radiographic examination and either by interview or by questionnaire. Twenty-two were commissioned to full duty. 23 had attended ranger or airborne school, and 16 had been in combat. Impairment of ordinary activities was noted by 12 and impairment of athletic endeavors by 24; pain by 71%; swelling by 66%; stiffness by 71%; and instability by 94%. Seventeen of the 32 had had a significant reinjury after the repair of the anterior cruciate ligament. Clinically, we can diagnose the isolated tear of the anterior cruciate ligament by four essential ingredients--a pop at time of injury, inability to continue participation, gross swelling of knee, and maximal swelling within 12 hr. The mechanism of injury is usually deceleration and change of direction, not contact with another player. The follow-up study on this small series indicates that the patients have progressive deterioration of the knee.     

Failure mechanisms of anterior cruciate ligament prostheses: in vitro wear study

Previous retrieval studies analyzing the cause of failure of anterior cruciate ligament (ACL) prostheses identified a wear mechanism. However, the relative importance of yarn on bone compared to yarn on yarn wear has not been clearly understood. Therefore, the objective of this study was to elucidate which type of wear is the dominant cause of clinical failure. A variety of ACL prosthetic structures were exposed to two in vitro tests: one for yarn on yarn and the other for a novel yarn on bone wear test system. The latter included the use of both smooth (uncut) and rough (cut) bone surfaces to simulate the conditions around the condyle and at the exit of the tibial tunnel, respectively. The damaged textile structures were viewed by SEM. The various fiber fracture morphologies were identified and classified for the two types of wear tests; for the smooth and rough bone surfaces; for the braided, knitted, woven, and twisted textile structures; and for the three types of fibers that were included: polyethylene terephthalate, polypropylene, and ultrahigh molecular weight polyethylene. The results confirmed that yarn on bone and yarn on yarn wear phenomena are associated with significantly different failure mechanisms. While the more aggressive rough (or cut) bone causes more rapid and intense fiber damage and faster ACL failure than the smooth (uncut) osseous surface, both abradants cause the same type of abrasive wear phenomenon. Differences in failure mechanisms were identified between the different textile structures and the different fiber types. By interpreting the damaged fiber images from clinically failed and retrieved ACL prostheses, we are now able to confirm that the predominant cause of synthetic ACL failure is yarn on bone abrasion. Improvements in future ACL prosthesis designs will only be possible by eliminating or minimizing the effect of this type of abrasive wear.     

Vascular anatomy of the ovine anterior cruciate ligament. A macroscopic, histological and radiographic study

Sheep are being extensively utilized in animal models for orthopaedic research, but the vascular anatomy of their anterior cruciate ligament (ACL) has not yet been thoroughly described. This study demonstrates the blood supply to the ACL. Vascular injection with plastogen G, lead oxide and India ink was performed in 12 back limbs of Styrian mountain sheep, and gross observations, microradiography and routine histology were done. The large vessel and the microvascular anatomy are similar to those described for humans. The middle genicular artery and the descending genicular artery contribute vessels that supply the ACL. Epiligamentous vascular plexuses give off capillaries which penetrate the ligament substance and supply numerous, longitudinally oriented intraligamentous vessels. These findings make the Styrian mountain sheep a potential animal model for biologic investigations of ACL pathology.     

Mechanisms of injury of the anterior cruciate ligament in soccer players

Despite the great amount of research that has been focused on the anterior cruciate ligament in recent years, relatively little is known about the exact mechanisms that cause these injuries. By defining the factors that contribute to these injury mechanisms in soccer players, the authors hope to facilitate appropriate training methods and work at preventing these serious injuries.     

Gonarthrosis after injury of the anterior cruciate ligament: a multicenter, long-term study

In order to estimate incidence, severity and associated factors in the development of the degenerative arthritis of the knee following a cruciate ligament injury, a multicenter, longterm follow-up study was undertaken. The time interval between injury and follow-up exam was a minimum of 15 years (range 15-52 years). Extensive physical examination and radiographic analyses from four "Knee Centers" (Hospital for Special Surgery, New York; Orthop?dische Klinik, Bruderholz; Orthopaedic and Arthritic Hospital, Toronto; Orthopaedic Department Wichita, Kansas) on 328 patients revealed that the best correlation to the degree of osteoarthritis could be found to the time of meniscectomy. All other operations (suture of cruciate ligament, intraarticular or extraarticular reconstruction) showed much less correlation to the severity of the degenerative arthritis found at the follow-up exam. In conclusion: Preservation of as much meniscus tissue as possible at the time of injury seems to be the best warranty for slowing down degenerative arthritis after cruciate ligament injury.     

Analysis of the drill hole orientation in anterior cruciate ligament reconstruction

In the reconstructive procedure of the anterior cruciate ligament (ACL), the relationship was investigated between the orientation of the drill holes from the isometric points and the deformity in the ligament graft. We first investigated, by numerical analysis, the optimal orientation of the drill holes for minimal deformation. Secondly, we experimentally by using eight fresh cadaveric knees, measured the relationship between the orientation of the drill holes and the bending angle in the grafts. The optimal orientation of the drill hole in the femur was found to be tilted 20 degrees laterally in the coronal plane and 23 degrees anteriorly in the sagittal plane. In the tibia, the drill hole should be directed 24 degrees medially and 50 degrees anteriorly from the isometric point. The numerically analysed bending angle corresponded well to the results from the experimental study. The deformation in the graft on the femoral side was larger than that on the tibial side. Therefore, the orientation of the femoral drill hole was concluded to be more important than the orientation of the tibial drill hole.     

Effects of cold and compression dressings on early postoperative outcomes for the arthroscopic anterior cruciate ligament reconstruction patient

Efforts to minimize the morbidity of anterior cruciate ligament (ACL) reconstruction include the use of cryotherapy and/or compressive dressings in the immediate postoperative period. We undertook the present study to determine if the alleged benefits of the Cryo/Cuff, which combines these modalities, are more attributable to its compressive effect rather than cold application. Seventy-eight patients admitted for primary endoscopic ACL reconstruction using a bone-patella tendon-bone autograft were randomized to receive Cryo/Cuff compressive dressings postoperatively. Forty subjects (Group 1) had the cuff applied with continuous circulating ice water using the Autochill device, while 38 others (Group 2) received the cuff with room temperature water. Cases were performed as inpatients and all subjects were administered intravenous morphine postoperatively via a patient-controlled infusion pump for the first 24 postoperative hours. At baseline, the groups were well matched in age, sex, duration of symptoms, operative time, and associated meniscal surgery. No significant difference between groups was detected with respect to length of hospitalization, Hemovac knee drainage, oral and intravenous narcotic requirement, or subjective pain as measured by a visual analog scale. No apparent complications related to the use of the Cryo/Cuff dressings were noted. The clinical effect of the Cryo/Cuff in this study was not influenced by the use of continuous ice water vs. room temperature water. Further study should focus on variations in compression to evaluate the clinical impact of this device.     

Tensile load and the metabolism of anterior cruciate ligament cells

It generally is recognized that tensile load plays a major role in maintaining the homeostasis of the anterior cruciate ligament fibers, but its detailed mechanism remains a matter of controversy. The effect of cyclic tensile load on the metabolism of the anterior cruciate ligament were investigated experimentally using cultured cells from the anterior cruciate ligament of rabbits. Using culture plates with flexible rubber bases, a cyclic tensile load was applied to the cultured cells for 24 hours, and the changes in shape, alignment, and metabolism of the cells were analyzed. Under the cyclic tensile load, the shape of the cells from the anterior cruciate ligament changed to spindle and aligned perpendicularly to the direction of the tensile load. The cyclic tensile load also caused an increase in collagen synthesis by the cells from the anterior cruciate ligament, which was predominant in Type I. The cells from the synovium showed similar changes in shape and alignment under the cyclic tensile load, but no significant change was observed in cell metabolism. These observations suggest that the application of cyclic tensile load on the anterior cruciate ligament cells is an important factor in the regulation of collagen synthesis in the anterior cruciate ligament.     

Acute repair of injury to the anterior cruciate ligament. A long-term followup

We reviewed 30 patients at an average of 7.4 years after acute repair of the anterior cruciate ligament augmented with a loop of iliotibial tract. A noncontact twisting had been the mechanism of injury in 18 of these patients, with 28 having been injured in sports. At followup, 25 patients had not experienced symptoms of instability and 23 were able to return to unrestricted athletic activity; only 5 had been unable or unwilling to return to sporting activity at all. There had been no swelling in 23 patients; however, 17 suffered from pain on exertion. The average Lysholm score was 93.2. Joint laxity was assessed and anteroposterior tibial translation quantified with a KT-1000 arthrometer. Eighteen patients had a normal or 1+ Lachman test and 27 had an absent or 1+ pivot shift. When compared with the results of a similar study performed on this group of patients at 2 years after surgery, there had been little subjective change in knee function. However, objectively there had been significant deterioration of the anteroposterior stability of the knees at 7 years, suggesting failure of the integrity of the repaired ligament with time. An associated medial collateral ligament injury had a significant adverse effect both on the integrity of the anterior cruciate ligament repair and the incidence of postoperative stiffness.