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Biomedical subjects

F H Fu

Publications and source records attributed to F H Fu.

At least 109 records · Page 6Linked to original sources
PubMed1994

Synovial fluid cytokine concentrations as possible prognostic indicators in the ACL-deficient knee.

Approximately 44% of patients develop osteoarthritis (OA) following rupture of the anterior cruciate ligament (ACL) if the injury is left unrepaired. Restoring knee stability through reconstruction, while providing symptomatic relief, has not been shown to reduce the incidence of degenerative changes. In fact, recent studies have shown that 50%-60% of ACL-reconstructed patients go on to develop degenerative changes or frank osteoarthritis. In light of these data, our group suggests that the cause of post-traumatic osteoarthritis is not biomechanical but biochemical. To test this hypothesis, we measured levels of nine cytokines which are important in modulating physiological and pathophysiological metabolism of cartilage in knee joint synovial fluid following ACL rupture. Our patient population contained both acute and chronic ACL ruptures. A total of 84 samples were collected and analyzed by enzyme-linked immunosorbent assay. On the basis of the data collected, we were able to identify subgroups of patients who, on the basis of their synovial fluid cytokine profile, may be at greater or lesser risk of developing post-traumatic OA. In general, patients displayed concentrations of interleukin-1 alpha (IL-1 alpha), basic fibroblastic growth factor (bFGF), transforming growth factor-beta (TGF-beta), granulocyte/macrophage-colony stimulating factor (GM-CSF), IL-6, and IL-8 that we interpreted as being consistent with an inflammatory reaction. Of great interest is the fact that the levels of these cytokines were very similar in patients 4 weeks after injury and in chronic patients, leading us to hypothesize that a chronic smoldering inflammatory reaction persists after resolution of the acute effusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Anterior Cruciate Ligament Injuries↗
PubMed1994

Anterior cruciate ligament reconstruction: endoscopic versus two-incision technique.

The purpose of this study was to compare the single-incision, "endoscopic" (ENDO) anterior cruciate ligament (ACL) reconstruction technique with the two-incision, "rear-entry" technique (RE). Sixty patients were entered into a prospective study. Thirty patients underwent ACL reconstruction by the RE technique, followed by 30 consecutive patients using the ENDO procedure. Postoperatively all patients followed a standardized rehabilitation protocol. Follow-up evaluation consisted of a detailed physical examination, range of motion, thigh girth, vertical leap, hop test, KT-1000 testing, and patient interview. They were scored according to the International Knee Documentation Committee (IKDC) protocol, which takes objective and subjective data into account. Patients were also assessed for level of sports activity including frequency and type. Finally, anteroposterior and lateral x-ray films were evaluated with a scoring system for tunnel location. Of the initial 60 patients entered into the study, 50 were available for a detailed clinical and functional review (83%). Demographic comparisons revealed 24 RE patients and 26 ENDO patients. There were 16 men and 8 women in the RE group. The ENDO group comprised 16 men and 10 women. There were 14 right knees and 10 left knees in the RE group. In the ENDO group there were 13 right knees and 13 left knees. The average age in the RE group was 24 years and 25 years in the ENDO group. The average follow-up was 35 months (range 31-40 months) in the RE group and 29 months (range 24-35 months) in the ENDO group. Complications included two patients with loss of motion in the RE group and three in the ENDO group. There were no significant differences between the two groups tested with respect to the overall IKDC rating scale. Anteroposterior and lateral x-ray films revealed no significant differences in femoral and tibial tunnel placement. In conclusion, no significant functional or radiographic differences at a minimum 2-year follow-up could be identified when comparing the two ACL reconstructive techniques.

Adult↗
PubMed1994

Biomechanical function of the human anterior cruciate ligament.

Knowledge about the biomechanical function of the anterior cruciate ligament (ACL) is very important in the treatment of the ACL deficient knee. This article presents an overview of the biomechanical function of the ACL, including its structural and mechanical properties as well as its role in knee stabilization and normal kinematics. Tensile properties of the prospective biological grafts and future directions in ACL research are also discussed.

Anterior Cruciate Ligament↗
PubMed1993

Determination of the in situ loads on the human anterior cruciate ligament.

A noncontact, kinematic method was used to determine the lengths and in situ loads borne by portions of the human anterior cruciate ligament (ACL) by the combination of kinematic data from the intact knee and load-length curves of the isolated ACL. Specimens from knees of cadavers of young people were tested in passive flexion and extension as well as with 100 N of anterior tibial drawer at 0, 30, 45, and 90 degrees of flexion. The results showed that the in situ load on the whole ACL (as much as 129 N) can exceed the magnitude of the applied anterior tibial drawer. The load distribution within the ligament changes with flexion of the knee. The anterior and posterior portions share the anterior drawer force equally toward full extension. However, at flexion > 45 degrees, the anterior portion supports 90-95% of the load. This information is important for the determination of the function of the entire ACL and of its subportions in response to external loading of the intact knee. In particular, the preferential loading found for one of the portions of the ACL demonstrates that successful operative reconstruction of this ligament may not be achieved simply by reproduction of its gross anatomy; consideration of the role of the ligament in the overall kinematics of the knee is necessary.

Adult↗
PubMed1993

The induction of IL-1 by freeze-dried ethylene oxide-treated bone-patellar tendon-bone allograft wear particles: an in vitro study.

There have been recent reports of adverse clinical results with freeze-dried ethylene oxide-treated bone-patellar tendon-bone (FD-ETO-BPTB) allografts used in anterior cruciate ligament (ACL) reconstruction. Ethylene oxide and its residues were implicated as the cause of many of the failures. Wear particles generated from both freeze-dried ethylene oxide-treated and deep frozen bone-patellar tendon-bone (DF-BPTB) allografts were placed in culture with lapine synoviocytes. The resulting synovial-conditioned media were then assayed for interleukin-1 (IL-1) content. IL-1 is a potent mediator of tissue inflammation. FD-ETO-BPTB wear particles generated statistically significant levels of IL-1 when compared with both a negative control and DF-BPTB wear particles.

Anterior Cruciate Ligament↗
PubMed1993

The arthroscopic "impingement test" during anterior cruciate ligament reconstruction.

A primary goal of ACL reconstruction is to avoid graft impingement, which may lead to loss of motion and/or an increased incidence of instability. Although surgeons are cognizant of this potential problem, the intraoperative correction of graft impingement is technically demanding because the graft-notch relationship is obscured by the trochlea articulating with the tibial plateau during the final 10 degrees of extension. We present a simple impingement test that is performed before graft insertion and fixation to help avoid this potential pitfall.

Anterior Cruciate Ligament↗
PubMed1993

Muscular and functional performance characteristics of individuals wearing prophylactic knee braces.

The efficacy of prophylactic knee bracing has been refuted with regard to reducing the incidence and/or severity of injuries to the knee joint. This is thought to be a result of the prophylactic knee brace's ineffectiveness in protecting the knee joint from valgus loads. Furthermore, discrepancies exist regarding the prophylactic knee brace's detrimental effect on functional performance. The purpose of this study was to measure the effect of the prophylactic knee brace on selected isokinetic muscular characteristics and forward sprint speed. Twenty physically active, healthy, male college students with no prior history of brace use participated in this study. The subjects were randomly tested both with and without the prophylactic knee brace worn on various performance parameters. The dependent measures assessed included peak torque (PT) and torque acceleration energy (TAE) at 60 and 240 degrees /s. A 40-yard forward sprint was selected to assess sprint speed. A paired t-test analysis revealed mean values which were significantly less for PT at 60 degrees /s (p < .05), 240 degrees /s (p < .01), and TAE at 240 degrees /s (p < .05) with the prophylactic knee brace applied during knee extension. Analysis also revealed slower times for sprint speed (p < .01), while the subjects were wearing the prophylactic knee brace. Muscular strength (PT) and power (TAE) scores were not correlated (p > .05) with sprint speed. This study suggests that wearing the prophylactic knee brace may consequently inhibit muscular and functional performance of the athlete, but that specific population has yet to be studied.

Journal Article↗
PubMed1993

Posterior cruciate ligament injuries.

Posterior cruciate ligament (PCL) injuries are more common than has been previously reported. Recent clinical and basic science studies have helped define the important functional anatomy and biomechanics of this "forgotten" ligament and have raised questions regarding the reported benign natural history of isolated tears of the PCL. While recent technical advancements in the application of magnetic resonance imaging to knee ligament injuries may assist in identifying PCL tears, the posterior drawer test remains the "gold standard" for diagnosis. Numerous treatment options have been proposed, but anatomical reconstructions have yielded consistently good clinical results. A review of our current knowledge of the basic science and clinical studies on the posterior cruciate ligament is presented to stimulate further interest and research in this exciting area.

Acute Disease↗
PubMed1993

The role of osteotomy in the anterior cruciate ligament-deficient knee.

Whether the ACL-deficient knee actually causes osteoarthritis is unclear. What is clear is that the two conditions can exist simultaneously. Treatment of these patients must be individualized based on their activities, symptoms, and findings. In the unusual patient with significant instability and moderate medial compartment osteoarthritis, a combined valgus osteotomy and ACL reconstruction may be appropriate. The authors emphasize that this is a salvage procedure, not intended to return the athlete to competition. Although the short-term results are promising, the long-term results of this treatment are unknown.

Animals↗
PubMed1993

Anterior cruciate ligament reconstruction: long-term results using autograft tissue.

Injuries involving the anterior cruciate ligament are quite common. Numerous surgical procedures have been proposed for the management of the symptomatic ACL-deficient knee. The most popular treatment modality is currently intra-articular reconstruction with the use of autogenous graft tissue. The focus of this article is to review the long-term results of autograft ACL reconstruction.

Animals↗
PubMed1993

The meniscus in the cruciate-deficient knee.

Evidence clearly implicates meniscectomy as a primary factor in the premature development of OA of the knee joint. Although data demonstrate the ability of the menisci to transmit load, they do not contribute to the primary stability of the knee. In the absence of the ACL, the menisci have been shown to enhance the knee's stability in the AP, varus-valgus, and internal-external directions in vitro. Clinically, the argument that the menisci are important secondary stabilizers is less clear. The restraining capacity of the menisci to AP translation is much smaller than the forces the knee is subjected to in vivo during activities of daily living. Additionally, these forces can increase as much as threefold during strenuous athletics. It becomes apparent, on review of the literature, that the menisci clearly are not designed to participate as a significant restraining mechanism for the ACL-deficient knee. The incidence of acute meniscal tear is 52% and increases to 83% in the long run. It is important to realize that although the menisci contribute in part to the stability of the ACL-deficient knee, such a role places them at risk for injury. When meniscal lesions are noted in the ACL-deficient knee, it is important to bear in mind the patient's goals, including his or her willingness to have an ACL reconstructive procedure and desire to return to sports. Also, the tear's configuration and location dictate its the ability to heal. One final area of interest relates to the fate of an ACL reconstruction in the meniscus-deficient knee. Although the meniscus is not a participant in primary stability, the subtle alteration in knee joint kinematics may create unfavorable conditions for the ACL graft. It is possible that the menisci may provide some protection to an ACL-reconstructed knee by restoring normal knee joint kinematics. Such a situation may explain why some ACL reconstructions in the meniscectomized knee fail over time. Prosthetic meniscal substitution or allograft meniscal transplantation are techniques on the horizon and may prove useful in the future when the remaining meniscus cannot be repaired.

Animals↗
PubMed1993

Revision anterior cruciate ligament surgery: causes of graft failure and technical considerations of revision surgery.

The frequency of revision ACL surgery is sure to become more common as the number of primary intraarticular reconstructions increase. Identifying the potential causes of failure through a detailed history, physical examination, and radiographic evaluation is of paramount importance prior to planning a revision surgery if the repetition of errors is to be avoided.

Anterior Cruciate Ligament↗
PubMed1993

[Study on cisplatin albumin microspheres for neck external artery embolization].

In this paper the technique of emulsion chemical-crosslinking was used to prepare cisplatin albumin microsphere for jaw squamous cancer by neck external artery embolization. It was yellow powder with yield 80 +/- 5%, mean size 56.3 microns, cisplatin concentration 14.02-14.20%, loading rate 97.08-97.95%. The release characteristics in vitro, sterilization, stability and recipe of disperse solvent of cisplatin albumin microsphere were investigated. Animal test showed that cisplatin albumin microsphere may plug the branches of neck external artery well and remain in local tissue.

Animals↗
PubMed1993

[Reconstruction of the cruciate ligaments with allogeneic transplants. Techniques, results and perspectives].

The authors have used allografts for reconstruction of the cruciate ligaments in over 600 cases since 1985. Advantages are the reduced operative trauma and the unlimited availability of high-quality grafts even in multiple ligament reconstructions. Arthroscopic techniques are available for reconstruction of the anterior and the posterior cruciate ligament, which makes arthrotomies and large skin incisions unnecessary. The grafts of choice are the bone-patellar tendon-bone preparation and the Achilles tendon with bone bloc. No specific complications were observed with the use of allograft material in this series. Results show a high subjective acceptance of the procedure among the patients, with a high rate of return to pre-injury sports activities following ACL reconstruction. Objective stability was restored in over 70% of these cases. All cases with posterior instability had 3+ posterior drawer preoperatively. At follow-up, almost normal stability had been restored in 50%. Further research must focus on the biological processes that take place during incorporation of these tissues and on better techniques of graft processing and sterilisation. At present, the risk of disease transmission must be considered and discussed with the patient.

Adolescent↗