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PubMed1992

Metabolic and biochemical status of articular cartilage following cryopreservation and transplantation: a rabbit model.

To determine the fate of transplanted cryopreserved articular cartilage, an animal model employing the proximal humerus in the rabbit has been developed. Previous studies have been hindered by problems of postoperative joint instability, secondary injury due to immobilization, and paucity of cartilage for analysis. This experiment demonstrates the survival and function of transplanted cartilage by quantitative assessment of metabolic and biochemical parameters. Forty-five New Zealand white rabbits underwent transplantation of the right proximal humerus. In 29 animals, the proximal half of the humerus was resected and replaced by a cryopreserved osteoarticular allograft. Autograft procedures were carried out in the remaining animals. Following sacrifice at 3, 6, 9, and 12 months postoperatively, articular cartilage was analyzed for gross appearance, collagen synthesis, proteoglycan synthesis, and water, hydroxyproline, hexosamine, and hexuronic acid contents. The results indicate that the cryopreserved osteoarticular allografts retained their metabolic and biochemical integrity and behaved as viable and biologically functional units 1 year postoperatively.

Animals↗
PubMed1995

Laxity characteristics of normal and pathological murine knee joints in vitro.

The aim of this study was to validate a device developed previously to measure laxity of murine knee joints and to investigate whether experimentally induced pathological conditions result in measurable laxity. The laxity characteristics of normal murine knee joints were derived from measurements of 25 left knees of normal mice. Reproducible, nonlinear s-shaped load-displacement curves were determined, and parameters of anterior-posterior translation, varus-valgus rotation, and compliance were calculated from the curves. No differences were found between the left and right knee joints of eight mice. The average displacement between 0.8 N of anterior force and 0.8 N of posterior force was 0.47 +/- 0.10 mm. The endpoint compliances for anterior and posterior displacements were 0.16 +/- 0.03 and 0.16 +/- 0.04 mm/N, respectively. The average rotation between a 4 Nmm valgus moment and a 4 Nmm varus moment was 17.4 +/- 3.3 degrees. The endpoint compliances for varus and valgus rotations were 1.1 +/- 0.7 and 1.0 +/- 0.3 degrees/Nmm, respectively. Storage of the joints at -70 degrees C had no effect on laxity. We also studied the parameters of laxity after pathology of the knee joint was induced. Zymosan-induced or antigen-induced arthritis did not increase laxity of the joint. In an osteoarthritis model induced by injection of collagenase, laxity was markedly increased. In conclusion, laxity in the knees of mice can be measured reproducibly and changes in the characteristics of laxity due to pathological conditions can be quantified.

Animals↗
PubMed2000

Decorin antisense gene therapy improves functional healing of early rabbit ligament scar with enhanced collagen fibrillogenesis in vivo.

Injured ligaments heal with scar tissue, which has mechanical properties inferior to those of normal ligament, potentially resulting in re-injury, joint instability, and subsequent degenerative arthritis. In ligament scars, normal large-diameter collagen fibrils have been shown to be replaced by a homogenous population of small collagen fibrils. Because collagen is a major tensile load-bearing matrix element and because the proteoglycan decorin is known to inhibit collagen fibrillogenesis, we hypothesized that the restoration of larger collagen fibrils in a rabbit ligament scar, by down-regulating the proteoglycan decorin, would improve the mechanical properties of scar. In contrast to sense and injection-treated controls, in vivo treatment of injured ligament by antisense decorin oligodeoxynucleotides led to an increased development of larger collagen fibrils in early scar and a significant improvement in both scar failure strength (83-85% improvement at 6 weeks; p < 0.01) and scar creep elongation (33-48% less irrecoverable creep; p < 0.03) under loading. This is the first report that in vivo manipulation of collagen fibrillogenesis improves tissue function during repair processes with gene therapy. These findings not only suggest the potential use of this type of approach to improve the healing of various soft tissues (skin, ligament, tendon, and so on) but also support the use of such methods to better understand specific structure-function relationships in scars.

Animals↗
PubMed2005

Preliminary results of a soft novel lumbar intervertebral prothesis (DIAM) in the degenerative spinal pathology.

The authors report a series of 43 patients suffering from lower limb pain, almost constantly associated with chronic or acute backpain, treated by microsurgical nerve root decompression and by implantation of a soft intervertebral prothesis (DIAM). Satisfying results were obtained in 97% of cases, inducing the authors to consider the device a reliable tool for curing low-back pain and sciatica. Selection criteria are exposed and discussed.

Adult↗
PubMed1984

Osteochondrosis dissecans of the knee. Results of operative treatment in juveniles.

This paper reports the results of 33 juvenile and 28 adult patients who were operated on for osteochondrosis dissecans of the knee. The average period of observation was 4.7 years. The results were compared according to age and stage of disease. The age of the patient at the time of operation doubtlessly has the greatest influence on prognosis. Juveniles operated on in stage II or III have a particularly good prognosis. From stage IV on it does not seem reasonable to try to preserve the dissecate. In the case of juveniles, metabolic or endocrinological diseases do not appear to be of any relevance, whereas mechanical factors like overstress during sports, hereditary ligament laxity, or deviations of the axis of whatever origin all seem to have some influence.

Adolescent↗
PubMed1988

General joint laxity. Quantification and clinical relevance.

General joint laxity is measured with the hyperextensometer, and by analyzing the values obtained in a group of European subjects norm curves are drawn up related to age and sex. The values found in various orthopedic diseases are put into these curves, and the importance of general joint laxity is discussed.

Adolescent↗
PubMed1996

Proprioception and joint stability.

In the present paper the current clinical knowledge about proprioception is given for the shoulder, knee, ankle, elbow and the radiocarpal joint. Proprioceptive capabilities are decreased after joint injuries such as ACL or meniscus tears, shoulder dislocation, ankle sprain and in joints with degenerative joint disease. Some surgical procedures seem to restore the proprioceptive abilities; others do not. Elastic knee bandages or ankle braces increase different proprioceptive factors like ankle reproduction capability or sports-specific abilities. The present information on proprioception will influence our clinical practice in the future. We should choose surgical procedures that not only reconstruct the anatomy, but also the neurophysiologic feed-back mechanism.

Algorithms↗
PubMed1991

Is the benign joint hypermobility syndrome benign?

Over a period of two years, joint hypermobility was identified in 95 female and 19 male patients who attended rheumatology and rehabilitation units in Ismailia city. Pauciarticular pains referring to large and medium-sized joints was their most frequent complaint. Clinical diagnosis of carpal and/or tarsal tunnel syndromes was made in 45.6% of patients, and various forms of soft tissue rheumatism were evident in 73% of them. On radiologic evaluation of the involved joints, 60.5% of the examined patients showed significant degenerative lesions. The most prominent finding in the study, however, was the aggregation of varieties of articular and extra-articular abnormalities in the same patient. Extra-articular features included high frequencies of occurrence of varicose veins, piles and uterine prolapse among other abnormalities. Thus, results of the study lend support to the view that joint hypermobility predisposes to several articular and nonarticular lesions raise serious questions about the reputable benignity of the syndrome.

Adolescent↗
PubMed2004

[Sports and pregnancy].

MATERNAL ASPECTS: Cardiorespiratory responses to exercise in pregnant women generally don't differ from those in nonpregnant women. Impairment of the cabability of the uteroplacental unit to maintain a sufficient oxygen and substrate supply to the fetus should be avoided by performing exercise in a submaximal range. Increase in body weight, a shift of the center of gravidity, and the ligamentous laxity in pregnancy lead to a certain joint instability and consecutively to an increased risk of injury. Therefore contact sports and sports with a high potential of injury are not suitable in pregnancy. Furthermore the beneficial effects of exercise on glucose metabolism especially in pregnant women with an impaired glusose tolerance, psychological well-being, delivery, and lactation are discussed. FETAL ASPECTS: Exercise results in an elevation of the fetal heart rate. So far no pathological heart rate alterations could be observed. There are controversial findings concerning the influence of exercise on birth weight. Actually no retardation below the 10th percentile could be demonstrated. To prevent pregnancy complications like preterm labour or placental abruption exercises with a risk of blunt abdominal trauma are not recommended in the 2nd and 3rd trimester. Additionally the effects of exercise on embryogenesis and the possible implications of hyperthermia are presented. CONCLUSION: In general, pregnant women should practise exercise in a moderate, i. e. submaximal aerobic range. Preexisting cardiopulmonary diseases and pregnancy pathologies have to be considered as contraindications. Thus gestational age adapted exercise represents a safe and effective support for mother and fetus. Recommendations concerning exercise in pregnancy underwent significant changes during the past three decades. Today there is a lot of evidence for the beneficial effects of moderate exercise in pregnancy even in formerly inactive women. This review first presents aspects of maternal and fetal physiology with special respect to exercise in pregnancy. Subsequently, risks and contraindications as well as the suitability of different kinds of exercise for pregnant woman are discussed.

Athletic Injuries↗
PubMed2005

[Ankle arthrodesis after failed joint replacement].

UNLABELLED: Report of four patients. OBJECTIVE: Restoration of a painless gait through ankle arthrodesis after failed total ankle replacement. INDICATIONS: Loosened or infected total ankle replacement. CONTRAINDICATIONS: Poor general health. Absent patient compliance. SURGICAL TECHNIQUE: Removal of total joint components. Filling of the defect with tricortical bone grafts harvested from the ipsilateral iliac crest and internal fixation. In instances of suspected infection a two-stage procedure is recommended, the first stage consisting of a removal of the components, a meticulous debridement, and filling of the defect with gentamycin-laden PMMA beads. Second stage: arthrodesis. RESULTS: The goal of surgery was reached without complications in two out of four patients. An absence of bony bridging was noted in the fourth patient after 9 months. A revision adding cancellous bone grafts and resorting to an intramedullary fixation led to a success.

Adult↗
PubMed2006

[Arthroscopic meniscal repair with an all-inside suture system].

OBJECTIVE: Application of an arthroscopic suture system to restore the form and function of the meniscus by adaptation of a longitudinal tear close to the base. INDICATIONS: Unstable longitudinal tears near the base of the meniscus, mainly in the posterior horn of the medial or lateral of the meniscus. Dislocated bucket-handle tears of the medial and lateral meniscus close to the base. CONTRAINDICATIONS: Poor tissue quality with fibrillated meniscal tissue. Meniscal tears in the avascular zone (zone I). Insufficient blood supply from the joint capsule and the base of the meniscus. Degenerative meniscal lesions. Anterior or posterior knee joint instability. Allergic reactions to nonresorbable suture material. SURGICAL TECHNIQUE: Standard anterior arthroscopic portals. Arthroscopic assessment of the meniscal tear using the probe. Revitalization of the tear margins and perforation of the meniscal base to induce bleeding. Adaptation of the tear margins and fixation with a suture-anchor system using an ipsilateral standard portal for tears in the posterior horn or by way of a contralateral standard portal for tears in the lateral horn. POSTOPERATIVE MANAGEMENT: Full weight bearing with the knee in extension in a knee immobilizer, relative to the pain threshold in the 1st postoperative week. Range of motion exercises without weight bearing from full extension to 90 degrees knee flexion (0/0/90). If simultaneous reconstruction of the anterior cruciate ligament (ACL) is being performed, rehabilitation protocols follow the principles for ACL reconstruction. RESULTS: Since the year 2000, meniscal tears in more than 300 patients have been repaired with the all-inside suture system. In the context of a multicenter study by ESSKA (European Society for Sports Medicine, Surgery and Arthroscopy) involving 20 patients, the result was evaluated by direct MRI arthrography (gadolinium). The suture bar anchors were generally not detectable, the incision channels produced a hypodense signal in the meniscus tissue. If re-rupture occurred, it was because the meniscus had pulled out of the suture loop. Cartilaginous lesions were not found. There were no complications related to the nonresorbable suture bar anchors.

Arthrography↗
PubMed2005

[Pyrocarbon prosthesis for finger interphalangeal joint replacement. Experience after one year].

The long-term results of finger joint replacement, particularly the proximal interphalangeal (PIP) joint, have mostly been disappointing according to a review of the international literature and our own experiences. The recently developed pyrolytic carbon implants (Ascension Orthopedics, Austin, Texas) for replacing the PIP joint were evaluated retrospectively regarding range of motion, functionality, and relief of pain. In our hospital 17 PIP joints were replaced with pyrolytic carbon implants in 16 patients by an offset stem technique inserted without cement. This study included 13 patients; we excluded three patients because of follow-up <3 months. Prerequisites were adequate collateral ligaments, bone stability, and sufficient or at least reconstructable extensor tendons. The purpose of this study was to evaluate the 1-year outcome (minimum 270, maximum 360 days) regarding range of motion, implant stability based on radiological and clinical parameters, and relief of pain using a pre- and postoperative visual and verbal analogue scale.There was an improved range of motion of the PIP joint from 0-28-51 preoperatively to 0-22-77 postoperatively (average value). On the visual analogue scale (0 no pain, 10 incapacitating pain) we achieved pain relief at rest and in motion of 80%. On the verbal analogue scale there was an improvement of 62%. The results of this study demonstrate that pyrolytic carbon implants reduce pain and are functionally superior to arthrodesis. A precise and individual postoperative protocol is necessary for beneficial results.

Adult↗
PubMed2005

[Therapeutic relevance of magnetic resonance imaging in joint injuries in children].

AIM: In this retrospective study, we assessed whether the use of MRI in children provides additional, therapeutically relevant information to assist in the diagnosis of joint injuries. In addition, we determined whether the usefulness of this approach is dependant on age of the child and localisation of the trauma. METHOD: MRI of 45 children aged between 3 and 16 years were analysed independently by four different investigators (two radiologists, two trauma surgeons) and assessed for their therapeutic relevance. RESULT: MRI of the knee (n=18) gave additional information in 11 patients (61%) and led to a change in the recommended therapy involving arthroscopy in seven patients (39%). MRI of the ankle (n=21) provided additional information in 12 patients (57%) and the decision for further therapy was influenced in six patients (29%), however, the indication for surgery was not influenced. The diagnosis of injuries of the elbow (n=6) was changed in four patients (67%), but the therapeutic decision was not influenced. CONCLUSION: MRI additional to conventional x-ray provides relevant information on the therapeutic procedure to be used for the knee, whereas for the ankle and the elbow MRI it rarely delivers additional information relevant to therapeutic decision making.

Adolescent↗
PubMed2007

[An improved vertebral body replacement for the thoracolumbar spine. A biomechanical in vitro test on human lumbar vertebral bodies].

BACKGROUND: In recent years, the use of expandable titanium cages for vertebral body replacement in the thoracolumbar spine has been well established for the treatment of tumors, unstable traumatic lesions, or posttraumatic deformity. Collapse of the implant into the vertebral body remains a point of concern. A biomechanical compression test was designed to assess implant subsidence for a newly developed prototype for vertebral body replacement in the thoracolumbar spine using human cadaveric lumbar vertebrae. The objective of this study was to compare the compressive performance of a new expandable cage with modified end-plate design with three commonly available expandable cages for vertebral body replacement. MATERIALS AND METHODS: The compressive strengths at the implant-vertebral body interface were measured via axial loading of the new prototype (Synex II) in comparison with three different expandable titanium cages: Synex I (Synthes), Obelisc (Ulrich Medical) and X-Tenz (DePuy Spine). Twenty-four intact, fresh frozen human lumbar vertebrae (L1-L4) were distributed into four identical groups according to BMD (determined by quantitative computed tomography) and the vertebral level. Specimens were loaded in the craniocaudal direction with a material testing machine at a constant speed of 5 mm/min. Load displacement curves were continuously recorded for each specimen until failure (diminishment of compressive force (F)/obvious implant migration through the vertebral body endplate). One-way analysis of variance and post-hoc tests (Bonferroni) were applied to detect differences at 1, 2, 3, 4 mm displacement (F1-4 mm), and Fmax between implant groups. RESULTS: The four expandable cages did not show statistically significant biomechanical differences in terms of maximum compression force (Fmax) until failure: Synex II (1,782 N/4.7 mm); Synex I (1,645 N/4.7 mm); Obelisc (1,314 N/4.2 mm); X-Tenz (1,470 N/6.9 mm). However, the mean compression force until 4 mm displacement (F1-4 mm: 300-1,600 N) was highest for Synex II. The difference at 2 mm displacement was significant (p=0.028) between Synex II (F2 mm=879 N) and X-Tenz (F2 mm=339 N). CONCLUSION: The modified endplate design of the new prototype was found to improve its compressive performance under constrained uniaxial loading conditions at the implant-bone interface. The improved compressive behaviour of the new implant might help to reduce the risk of implant subsidence and collapse into the vertebral body in vivo.

Aged↗
PubMed2002

[Bore canal site in surgical reconstruction of the anterior cruciate ligament. Position--placement errors--anatomic measurement].

The goal of surgical reconstruction of the anterior cruciate ligament (ACL) is restoration of its function as closely as possible to a physiological roll-and-glide mechanism. Clinical success means knee joint stability, physiological joint biomechanics, and full range of motion. Anatomical placement of the graft insertion points and anatomical direction of the drilled tunnels are necessary to obtain isometric (anatometric) conditions. Despite technical advances in (arthroscopic) surgery, it is not yet possible to obtain absolute "isometricity" for ACL grafts. However a "physiological" or "relative" isometricity seems to be sufficient for successful clinical results. In 1986 Werner Müller proposed the term "anatometrics" in ACL reconstruction to describe this graft behavior and function. The knee joint is a complex motion system including many active and passive stabilizing elements (ligaments, tendons, muscles) as well as a proprioceptive function of the central column ligaments. Reconstruction of this "system" required the surgeon to have good surgical skills and a well-based knowledge of knee anatomy and function. Wrong placement of insertion points and bone tunnels carry the risk for ensuing graft insufficiency and resultant joint instability. The knee "prefers" a destroyed graft over an overconstrained biomechanical situation! Intraoperative factors for failure may be technical mistakes and intraoperative measuring devices for isometry, which might not guarantee true relations in a ligamentous deficient knee. Therefore, visualization of insertion points (and drilling) under direct arthroscopic view is still preferred over generalized rules and distances as proposed by many commercially available rulers and tapers. Recently, navigation and computer-assisted placement techniques have been developed. The clinical standards of those techniques are still under investigation. At our institution, an arthroscopic approach (visualization, palpation) for ACL reconstruction with a bone-patellar-tendon-bone graft technique is used.

Anterior Cruciate Ligament↗
PubMed2006

In vivo MRI of cartilage pathogenesis in surgical models of osteoarthritis.

OBJECTIVE: To examine in vivo time-course changes in macromolecular composition of articular cartilage in two surgical models of osteoarthritis (goat: meniscal transection and cartilage incision; rabbit: medial meniscectomy). DESIGN: Collagen integrity and proteoglycan (PG) content were evaluated in both models by magnetization transfer (MT) and contrast-enhanced MRI, respectively. The MT rate k(m) for the exchange process between the bulk water and water bound to collagen was determined as a marker of the collagen network. Local changes in cartilage fixed charge density, i.e., where PGs are depleted, were derived from T(1) relaxation maps as obtained after an infusion of Gd(DTPA)(2-), a paramagnetic agent. RESULTS: In the goat model, the MT rate constant k(m) was significantly higher at 2 weeks post surgery, a possible sign of cartilage swelling, then decreased below baseline values, most likely indicative of disruption in the collagen framework. Meanwhile, post-Gd(DTPA)(2-) MRI acquisition indicated a significant and sustained loss of PGs. The rabbit model produced milder lesions. Although the difference was non-significant, k(m) steadily decreased in response to the surgical insult while kinetics of Gd(DTPA)(2-) uptake, after reaching a peak level at 6 weeks, were back to normal values after 12 weeks. CONCLUSION: In the goat model, joint instability and cartilage damage was a permanent trigger for cartilage degeneration producing MRI changes. However, biomechanical stress due to partial medial meniscectomy in knees of mature rabbits produced only mild, focal lesions and PG depletion that was partially reversible. This proof-of-concept study identified MT and T(1) parameters as useful surrogate markers in animal models of osteoarthritis.

Analysis of Variance↗