The intra-articular use of bio-degradable polymer coated carbon filament as an adjunct to repair or reconstruction of cruciate ligaments.
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Soft tissue releases are performed to correct fixed deformities in total knee arthroplasty. The goal of this in vitro study was to investigate the relationship between the individual steps in a medial (eight anatomic specimen knees) or lateral (four anatomic specimen knees) soft tissue release sequence, the resulting change in the medial and lateral tibiofemoral gaps, and the change in coronal angulation caused by 10 Nm varus and valgus moments in extension and 90 degrees flexion. An optical encoder was used to measure the coronal angulation. The tibiofemoral gaps were measured with calipers with the knee distracted by a 53-N load. In the medial release sequence, a significant increase in coronal angulation and medial gap occurred after the release of the anteromedial sleeve 8 cm from the medial joint line. In the lateral release sequence, there was a significant increase in the coronal angle and lateral gap after the lateral collateral ligament and popliteus tendon were released from the femur. Release of the posterior cruciate ligament led to a significant increase in angle and gap in medial and lateral release sequences. These results are specific for the particular release sequences studied, with release of the posterior cruciate being the final step in each sequence.
A model of knee mobility able to predict the range and pattern of movement in the unloaded joint was proposed by Wilson et al. (J. Biomech. 31 (1998) 1127-1136). The articular surfaces in the lateral and medial compartments and isometric fascicles in three of the knee ligaments were represented as five constraints on motion between the femur and tibia in a single degree-of-freedom parallel spatial mechanism. The path of movement of the bones during passive flexion was found by solving the forward kinematics of the mechanism using an iterative method. The present paper shows that such a mechanism-based solution approach can lead to an underestimation of the flexion range. This is due to the mechanism reaching a 'stationary configuration' and 'locking'. A new, constraint-based approach to the solution of the model joint displacement is proposed. It avoids the representation of ligaments and articular surfaces by kinematically equivalent chains of one degree-of-freedom pairs which are prone to singularities. It relies instead on a numerical solution of five non-linear constraint equations to find the relative positions of the bones at a series of flexion angles. The method is successful both in its ability to predict motion through a physiological range and in its efficiency with a solution rate forty times faster than the original algorithm. The new approach may be extended to include more complex joint surface geometry, allowing a study of the effects of articular surface shape and ligament arrangement on joint kinematics.
UNLABELLED: Reconstruction of the anterior cruciate ligament (ACL) is associated with a considerable degree of postoperative pain. Our customary multimodal approach to postoperative analgesia after ambulatory ACL surgery includes perioperative nonsteroidal antiinflammatory drugs, pre- and postincisional intraarticular (I.A.) bupivacaine (B), and postoperative cryotherapy using an external cooling system. This study was designed to determine whether the addition of I.A. morphine (MS) provides improved postoperative analgesia. One hundred patients scheduled for elective ambulatory ACL repair received our standard multimodal therapy. After surgery, patients were randomized to one of four study groups. Group 1 received 30 mL of 0.25% B I.A. Group 2 received 30 mL of normal saline I.A. and 5 mg of MS I.A. Group 3 received 30 mL of 0.25% bupivacaine I.A. and 5 mg of MS I.V.. Group 4 received 30 mL of 0.25% B I.A. and 5 mg of MS I.A. The addition of I.A. B postoperatively provided prolonged analgesia and decreased postoperative pain and analgesic requirements. The addition of MS to I.A. B did not provide additional postoperative analgesia. We conclude that patients undergoing ambulatory ACL repair using our standard multimodal analgesic regimen failed to receive additional postoperative analgesia when MS was added to the I.A. B. IMPLICATIONS: Patients receiving a multimodal analgesic regimen of perioperative nonsteroidal antiinflammatory drugs, intraarticular bupivacaine, and external cooling did not receive any additional analgesia from intraarticular morphine.
Between June 1990 and December 1997 116 patients with complete dislocation of the acromio-clavicular joint were treated operatively. According to the classification of Tossy and Rockwood all patients had type Tossy III or Rockwood III, IV and V of lesion. The retrospective part of the study from June 1990 to August 1994 represents 48 patients treated in 31 cases with wire-cerclage, in 14 cases with PDS-cerclage and in 3 cases with a combination of Kirschner wires and PDS. In a second group between September 1994 and 1997 68 patients were treated operatively with a special hook-plate, called Balser-plate, combined with suture of the corakoclavicular ligaments, the articular capsule and the intraarticular discuss. In the first group there was a postoperative immobilisation of the injured shoulder for 2,3 weeks necessary; in comparison to non immobilisation at the Balser-plate group. The range of motion in the Balser-plate group was free up to 90 degrees abduction. The removal of implants was performed in both groups after approximately 3 month. Postoperative complications were 8 reluxations at the acromio-clavicular joint and 10 superficial infects at the Non-Balser group and 4 superficial infects and 2 subcutaneous haematoma in the Balser group. We saw no reluxation in the Balser group. We examined 30 of 48 patients of the Non Balser group after average 50.1 month and 57 of 68 patients of the Balser group after 24.6 month. We compared the functional result, a questionnaire and the ultrasound examination of the acromio-clavicular joint with and without 10 kg weight bearing of the arm. 87.7% of the Balser patients and 67.7% of the Non-Balser-patients had free movement of the injured shoulder. Another 14.2% and 11.4% of the Balser group complained on shoulder pain with weight bearing and extreme moval in comparison to 17.4% of the Non-Balser group. At ultrasound examination comparing the injured to the non injured arm with and without 10 kg weight bearing there was a clavicula-elevation of 0.3 mm and 0.6 mm at Balser-patients and 3.0 mm and 2.5 mm at Non-Balser-patients for the injured side. In normal position the acromio-clavicular width was physiological in 50.2% of Balser patients in comparison to 36.6% of Non-Balser-patients. Under weight bearing the acromio-clavicular width increases in both groups. 63.2% of the Balser-group patients are satisfied with the result of operation, but only 43.3% of the other group (p < 0.05). Completely dissatisfied were 20% of the Non-Balser group, particularly because of the bad cosmetic result (40%).
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A method for measuring the expression of integrin subunits on the cell surface of knee ligament fibroblasts was developed with use of flow cytometry and immunofluorescence. The ligament cells exhibited uniform size and density, as shown by forward and side-scatter properties, and showed minimal nonspecific binding of isotype control antibodies compared with unstained cells. All cells expressed the alpha5 integrin subunit; lateral collateral ligament cells stained with antibody to alpha5 showed a mean fluorescence intensity 2-fold higher than that of medial collateral ligament cells, 1.5-fold higher than that of posterior cruciate ligament cells, and 3-fold higher than that of anterior cruciate ligament cells, indicating a greater expression of the alpha5 subunit by lateral collateral ligament cells than by medial collateral, posterior cruciate, and anterior cruciate ligament cells. All cells expressed the beta1 integrin subunit; the expression by posterior cruciate ligament cells was 3-fold higher than that by medial collateral ligament or lateral collateral ligament cells and 5-fold higher than that by anterior cruciate ligament cells. All cells expressed the beta3 integrin subunit; the expression by posterior cruciate ligament cells was 1.5, 3, and 4.5-fold greater than that by lateral collateral, anterior cruciate, and medial collateral ligament cells, respectively. Our data suggest there is a differential expression of integrin subunits in knee ligament fibroblasts, and this in part may explain differences in their attachment and adherence to extracellular matrix molecules.
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Failures of arthroscopic partial meniscectomy do occur but are not often reported. This paper reports a series of 291 attempted arthroscopic partial meniscectomies. Follow-up was achieved in 268 patients; 4 required arthrotomy initially, 22 failed to benefit from treatment and a further 15 required two arthroscopic operations before improvement occurred. The main reasons for failure were initial inadequate assessment and treatment of the meniscal tear, the presence of dual pathology and the development of a second tear in the meniscal remnant.
There has been remarkable advancement in arthroscopy of the knee since Watanabe's 21 arthroscope in 1959. Our understanding of knee pathology has been advanced and new syndromes have been described. The internal structures of the knee can now be visualized with magnification-promoting diagnostics. Equipment has been designed specifically for knee arthroscopy, allowing for advances in technical procedures and for surgery not heretofore anticipated. Skilled arthroscopists can perform meniscectomy routinely. The next few years should allow development of instruments for continued advancement of techniques and also to allow clinical research to assess the value of many of the procedures in use today. Arthroscopy, both diagnostic and therapeutic, is a safe procedure with minimum morbidity. Moreover, in the near future, arthroscopy will assuredly advance to become routine in several other joint, particularly the ankle and shoulder.
A cadaver study was performed to evaluate the effects of partial and complete excisions of the articular disk of the triangular fibrocartilage complex on the kinematics of the distal radioulnar joint and the structural integrity of the triangular fibrocartilage. An excision that did not violate the peripheral 2 mm of the disk and that comprised less than two thirds of the disk area resulted in no significant kinematic or structural changes, but larger excisions produced measurable changes. These results provide further support for limited excision of central triangular fibrocartilage complex tears.
OBJECTIVES: To estimate the incidence of ligamentous knee injuries in patients with traumatic brain injury (TBI) involved in pedestrian versus motor vehicle collisions (PVMVC), to identify associated risk factors, and to compare rehabilitation outcomes and costs in TBI patients with and without ligamentous knee injury. DESIGN: Retrospective, case control. SETTING: An academic rehabilitation hospital with a large metropolitan referral base. PATIENTS: Twenty-three consecutive adolescent and adult subjects admitted for acute inpatient rehabilitation after a PVMVC from January 1, 1994, to January 1, 1996. RESULTS: Five subjects (22%) were found to have a ligamentous knee injury, one with bilateral injuries. Two of these six injuries were diagnosed only after presentation to the rehabilitation setting. The most common injury was an anterior cruciate ligament (ACL) disruption in 5 of 6 knees. A coupled ACL and medial collateral ligament injury was identified in 4 of 6 injured knees. The risk of ligamentous knee injury was most closely associated with the presence of a tibial plateau fracture (n=3) (chi2=12.420, p < .001). There was no statistical difference between groups with and without ligamentous knee injuries with respect to age, gender, inpatient acute or rehabilitation length of stay, admission, discharge, or change in motor Functional Independence Measure (FIM) interval measures, or rehabilitation costs. Four of the 5 patients with ligamentous knee injuries were successfully managed nonoperatively. A case illustrating longitudinal management is presented. CONCLUSIONS: TBI and ligamentous knee injuries, in particular ACL injuries, are common comorbidities after PVMVC. Physicians must maintain a high index of suspicion for ligamentous knee injuries in this population, particularly when a tibial plateau fracture is present. TBI patients with and without ligamentous knee injuries can have comparable functional outcomes when the ligament injuries are identified and appropriately managed, without incurring undue cost or length of inpatient rehabilitation.
The variety of injuries that occur in the joints of the hand range from skin abrasions to displaced intra-articular fractures. This article discusses serious injuries involving ligaments, volar plate, and bones at specific anatomic regions of the joints of the hand.
An experimental model with a static positioning frame, pressure-sensitive film (Fuji), and a microcomputer-based video digitizing system, previously developed by the two senior authors, was used in this study to examine the effects of increasing perilunate instability on the load transfer characteristics of the wrist. These effects included a significant dorsal ulnar shift of the scaphoid centroid with increasing perilunate instability together with a less dramatic palmar ulnar shift of the lunate centroid. Overall, the scaphoid contact area was found to decrease as the stage of perilunate instability increased, even in ulnar deviation and/or extension, which in the normal wrist was found to be the positions that had the greatest scaphoid contact area. Average pressures in the high pressure zones were found to significantly increase in wrists with a stage III instability compared with normal wrists. An increase in the intercentroid (scaphoid/lunate) distance was most evident with the wrist in 20 degrees extension, neutral radioulnar deviation, and 90 degrees supination.
No prosthesis yet designed for replacement of the metacarpophalangeal (MCP) joint incorporates all considerations of anatomy and geometry of the natural joint to restore the normal kinematics. Loss of stability, recurrent deformity, and early loosening are persistent problems. In this study, a detailed three-dimensional geometric analysis of the MCP joint was performed. The sagittal contours of both metacarpal heads and base of the proximal phalanx under loaded and unloaded conditions were analyzed. The geometric parameters of the MCP joint articulating surfaces were analyzed, including the center and radius of curvature and the location and size of the contact area. The pressures on articulating surfaces during various hand functions were also established. These findings provided important information for better understanding the kinematics of finger joint articulation, as well as the cause of joint degeneration.
Wheat germ agglutinin-horseradish peroxidase conjugate (WGA-HRP) was injected into the dorsal root ganglia (L5-S1) of the cat and used as an anterograde tracer substance for intra-axonal labelling of peripheral nerve endings in joint capsule and cranial (anterior) cruciate ligament (CCL). We believed that the high specificity of WGA-HRP for neural tissue along with the high visibility of its reaction product could help resolve controversies concerning the sensory innervation of the cruciate ligaments. Substantial amounts of WGA-HRP were transported in tibial nerve axons to the level of the knee. However, using standard HRP histochemistry we found that the capsular tissue and ligament synovia disintegrated during the incubation reaction. This problem was avoided by air drying the tissue slices on glass slides prior to reaction. Abundant labelling occurred in the posterior capsule with dense filling of axons and terminal endings. Sensory endings displayed features consistent with Ruffini endings and pacinian corpuscles. Sensory endings were located throughout the CCL in its sagittal plane, in the subsynovial layers and between collagen fascicles. In each CCL we observed 5-17 ovoid and elongated endings with dense terminal arborisations. These endings were between 100 and 150 microns long, were encapsulated, and gave rise to 1 or 2 axons. Large (up to 1.5 mm in maximum extent) elongated regions of dense, inhomogeneous labelling were found in the body of several CCLs. These resembled Golgi tendon-like endings, with the exception of their large size. We conclude that anterograde transport of HRP to the knee is a useful technique for labelling mechanoreceptors and axons in knee tissue. However, recently developed immunohistochemical analysis of peripheral tissue using protein gene product 9.5 appears to be the method of choice and should be employed for further study of human and animal cruciate ligament innervation.
The common clinical problem of carpal instability is often difficult to diagnose with the precision necessary to confidently direct appropriate treatment. The role of magnetic resonance imaging (MRI) in the evaluation of carpal instabilities is evolving but remains problematic. Finding solutions to these problems is contingent upon both the imaging specialist and clinician appreciating the full scope and clinical implications of the mechanical and kinematic complexity inherent in the anatomic design of the carpus. Providing specifics about the clinical questions that arise with various carpal instabilities serves to highlight the challenges facing current imaging technology, and provides a framework that supports the argument for the development of dynamic MRI as one--and perhaps the only--truly satisfactory solution to this problem.
STUDY DESIGN: An animal study was conducted to assess whether different surgical procedures of spinal fixation and destabilization would influence the biomechanics and histology of lumbar spinal ligaments. OBJECTIVES: To investigate the effects of spinal fixation and destabilization as well as surgical intervention itself on the biomechanical and histologic properties of lumbar spinal ligaments. SUMMARY OF BACKGROUND DATA: Although several investigators have reported normal biomechanical properties of different spinal ligaments, there have been no studies in which changes in spinal ligament properties, secondary to the altered biomechanical environment provided by such surgical procedures as spinal fixation and destabilization, have been investigated. METHODS: Thirty-six mature sheep were divided into four groups: Group I: nonsurgical control: Group II: sham operation consisting of bilateral posterolateral exposure at L4-L5; Group III: spinal fixation using transpedicular screws and plates and bilateral posterolateral bone graft at L4-L5; and Group IV: spinal destabilization consisting of bilateral facetectomy and anterior discectomy at L4-L5. Four months after surgery, the biomechanical analysis included destructive tensile testing of four different bone-ligament-bone complexes at the operative and proximal adjacent levels: anterior longitudinal ligament, posterior longitudinal ligament, ligamentum flavum, and supraspinous and interspinous ligaments combined. Histomorphometric analyses of the vertebral body and spinal ligaments were performed histomorphometrically. RESULTS: Biomechanical analysis results demonstrated remarkable changes in the structural and mechanical ligament properties at the operative level. The fixation group's ligaments showed consistent decreases in the ultimate load and elastic modulus compared with those parameters in the control group (P < 0.05). Histologically, the fixation group's ligamentum flavum showed marked vacuolation in the ligament substance, whereas the interspinous ligament exhibited significant insertion changes compared with little change in substance. In all eight sheep in Group IV, unintentional bilateral facet fusions were obtained; and in all eight animals in Group III with pedicle instrumentation and posterolateral fusion, solid arthrodesis was exhibited. This allowed a distinction to be made between the stress-shielding effect of spinal instrumentation and arthrodesis (Group III) versus spinal fusion alone (Group IV) on both spinal ligament and vertebral body. Group II (sham) had a significant decrease in supraspinous and interspinous ligaments, but nonsignificant decreases in the stress-shielding effect of 10-12% in other ligaments. CONCLUSIONS: Posterior spinal instrumentation and fusion led to decreased biomechanical properties of the ligamentum flavum, posterior longitudinal ligament, and interspinous and supraspinous ligaments. The stress-shielding effects were ligament dependent and were most pronounced on the posterior side. The altered biomechanical environment produced by spinal fixation, surgical intervention itself, or nonphysiologic mobilization can affect the ligamentous properties in vivo, possibly serving as the impetus for low back pain.