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At least 559 records · Page 31Linked to original sources
PubMed2006

Comparison between high-resolution MRI with a microscopy coil and arthroscopy in triangular fibrocartilage complex injury.

PURPOSE: To determine whether high-resolution magnetic resonance imaging (MRI) could detect injuries to the triangular fibrocartilage complex (TFCC). METHODS: Eleven patients who showed both a positive sign during the ulnocarpal stress test and tenderness at the distal end of the ulna had a high-resolution MRI using a 47-mm diameter microscopy coil. Six regions of the TFCC were investigated for injury: the radial attachment, disc, ulnar attachment of the triangular fibrocartilage (TFC), ulnotriquetral ligament, palmar radioulnar ligament (PRUL), and dorsal radioulnar ligament (DRUL). Arthroscopy was performed subsequently on each patient. RESULTS: For injuries to the radial attachment or the disc of the TFC, a high-resolution MRI showed 100% sensitivity and 100% specificity compared with arthroscopy. In 3 cases in which injury to the ulnar attachment of the TFC was detected with MRI and examination showed a positive piano-key sign and distal radioulnar joint instability, only 1 injury was confirmed with arthrotomy. For MRI diagnosis of an ulnotriquetral ulnolunate attachment injury, the sensitivity was 100% and the specificity was 70%; however, 3 cases had false-positive results. Finally MRI had 100% sensitivity for detecting DRUL and PRUL injuries, although specificities were 75% and 83%, respectively. With MRI there were 2 false-positive DRUL injury diagnoses and 1 false-positive PRUL injury diagnosis. CONCLUSIONS: High-resolution MRI using a microscopy surface coil allowed assessment of each TFCC component and showed a higher accuracy for diagnosing injuries to the radial attachment and the disc of the TFC compared with previous studies. High-resolution MRI, however, was not able to diagnose DRUL, PRUL, or ulnolunate ligament injuries accurately. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic III.

Adolescent↗
PubMed2005

Early post-traumatic osteoarthritis-like changes in human articular cartilage following rupture of the anterior cruciate ligament.

OBJECTIVE: Injury to the anterior cruciate ligament (ACL) frequently leads to post-traumatic osteoarthritis (OA). In this study we determined whether early degenerative changes characteristic of idiopathic OA are induced in articular cartilage following ACL injury. METHODS: A small sample of femoral articular cartilage was removed at surgery, as part of ACL reconstruction, from a total of 50 patients with ACL injuries. Of these, 28 underwent surgery less than 1 year post-injury. Control cartilages were obtained from the same site from 21 persons at autopsy. All cartilages were examined for molecular changes. The content of type II collagen, its cleavage by collagenases and its denaturation were determined by immunoassay. The total content of glycosaminoglycan (GAG), which is principally aggrecan, was measured colorimetrically. Data were expressed per unit DNA (GAG and collagen content) or as a percentage of total collagen cleaved or denatured. Other cartilages from the same site (8 controls, 12 less than 1 year and 8 more than 1 year post-injury) were frozen sectioned and examined histologically to determine by Mankin grading cartilage degeneration. RESULTS: Histological analyses revealed that control subjects exhibited staining for proteoglycan, which was reduced in some patients following ACL rupture. Degeneration of the articular surface was sometimes observed 1 year after ACL rupture. Although the Mankin grade increased with time after rupture these changes were not significant. Immunoassays, however, revealed an increase in GAG content within 1 year which was maintained after 1 year although no longer significant. No changes in total type II collagen content were observed during the period of study. However, there were significant increases in the denaturation and cleavage of type II collagen less than and more than 1 year post-ACL rupture. Total type II collagen content was directly correlated with GAG content in all three groups, with the significance being weakest at more than 1 year. After 1 year an inverse correlation was observed between total type II collagen content and collagen cleavage as well as denaturation. CONCLUSIONS: These observations reveal that joint instability resulting from ACL injury rapidly results in degenerative changes characteristic of those seen in idiopathic OA at arthroplasty and in experimental OA following ACL surgery. These changes may contribute to the development of post-traumatic OA that is commonly observed following ACL injury. The observations support and extend conclusions from other studies on human and animal articular cartilage and synovial fluids post-ACL injury that have revealed a rapid onset of damage to type II collagen and an initial increase in proteoglycan content characteristic of experimental OA post-ACL injury. This study provides direct evidence for the rapid development of degenerative changes characteristic of OA following ACL injury.

Adolescent↗
PubMedDate not supplied

Humeral windows in revision shoulder arthroplasty.

Currently, there are no published results of patients in whom a window in the humeral cortex had been created to facilitate revision of a failed shoulder arthroplasty. Therefore, we reviewed the results of patients who underwent creation of a humeral window in the course of a revision shoulder arthroplasty to determine the complications and rate of healing. Twenty patients underwent humeral osteotomy to remove a well-fixed humeral component during the course of revision shoulder arthroplasty at our institution between January 1, 1987, and December 31, 2002. There were 17 cemented humeral components and 3 fully textured, press-fitted components. Of the shoulders, 16 had an anterior window, 3 had a medial window, and 1 had combined anterior and medial windows. There were 4 intraoperative fractures: 3 in the humeral shaft and 1 in the greater tuberosity. At the most recent radiographic follow-up at a mean of 3.3 years (range, 3-176 months), 17 of 20 windows had healed. Among 3 patients with limited radiographic follow-up (1, 3, and 4 months), 2 were healing and 1 did not demonstrate radiographic signs of healing. There were no cases of window malunion. No humeral components have developed clinical loosening. The data from this study suggest that humeral windows may facilitate controlled removal of well-fixed humeral components with a high rate of union. Further evolution of this technique may result in a lower fracture rate.

Aged↗
PubMed2006

Biomechanical comparison of component position and hardware failure in the reverse shoulder prosthesis.

There has been renewed interest in reverse shoulder arthroplasty for the treatment of glenohumeral arthritis with concomitant rotator cuff deficiency. Failure of the prosthesis at the glenoid attachment site remains a concern. The purpose of this study was to examine glenoid component stability with regard to the angle of implantation. This investigation entailed a biomechanical analysis to evaluate forces and micromotion in glenoid components attached to 12 polyurethane blocks at -15 degrees, 0 degrees, and +15 degrees of superior and inferior tilt. The 15 degrees inferior tilt had the most uniform compressive forces and the least amount of tensile forces and micromotion when compared with the 0 degrees and 15 degrees superiorly tilted baseplate. Our results suggest that implantation with an inferior tilt will reduce the incidence of mechanical failure of the glenoid component in a reverse shoulder prosthesis.

Arthritis↗
PubMed2006

The effect of glenoid component size on the stability of total shoulder arthroplasty.

Frequently, during the course of total shoulder arthroplasty, the measurement of the patient's native glenoid is between the available prosthetic glenoid sizes. Technically, it may be easier for the surgeon to implant a smaller glenoid component. Currently, there is no information regarding the difference in joint stability by use of glenoid components of different sizes. Stability ratio measurements were performed by use of a multiaxis testing machine with 3 different glenoid sizes (small, medium, and large) and compared by use of analysis of variance and the Tukey HSD test. Changes in the size of the glenoid component were found to have a significant effect on the stability ratio. At a load of 50 N, the stability ratio increased by 18% from the small to the medium glenoid component and by 15% from the medium to the large glenoid in the superoinferior axis. In the anteroposterior axis, the stability ratio increased by 17% from small to medium and by 10% from medium to large. The results from this study indicate a modest increase in stability when one chooses the larger of the 2 glenoid components.

Arthroplasty, Replacement↗
PubMed2006

Hydrogen peroxide as an irrigation solution in arthroplasty - a potential contributing factor to the development of aseptic loosening.

The reason for revision of primary total hip arthroplasty is quoted as aseptic loosening in 60.6% of cases between 1979 and 2003 in the Swedish National Hip Arthroplasty Registry. Much research effort has been directed toward enhancing the bone-cement interface of total joint arthroplasties, in an attempt to reduce this complication. Haemostatic agents have been popularized as effective means of retarding the development of potentially harmful debris interposition adjacent to, and blood lamination patterns within, the methylmethacrylate. Such agents include hydrogen peroxide (H(2)O(2)), local freezing saline, saline at room temperature and adrenaline solution. One main concern with the use of hydrogen peroxide is whether it affects the material properties of bone cement such that in the long term it contributes to aseptic loosening. This would have enormous clinical consequences. Preliminary studies indicate that porosity increases and that the tensile strength and yield stresses are reduced by up to a factor of 10 by contaminating samples with increasing concentrations of hydrogen peroxide. We postulate that the current use of hydrogen peroxide as an irrigation solution in arthroplasty contributes to the development of aseptic loosening.

Adhesiveness↗
PubMedDate not supplied

Response of Charité total disc replacement under physiologic loads: prosthesis component motion patterns.

BACKGROUND CONTEXT: Total disc replacement (TDR) has been recommended to reduce pain of presumed discogenic origin while preserving spinal motion. The floating core of Charité TDR is professed to allow the replication of the kinematics of a healthy disc under physiologic loads. While segmental motion after Charité TDR has been measured, little is known about the effects of a physiologic compressive preload on vertebral motion and the motion of prosthesis components after TDR. PURPOSE: (1) Does Charité TDR allow restoration of normal load-displacement behavior of a lumbar motion segment under physiologic loads? (2) How do the prosthesis components move relative to each other under physiologic loads when implanted in a lumbar motion segment? STUDY DESIGN: A biomechanical study using human lumbar spines (L1-sacrum). METHODS: Five lumbar spines (age: 52+/-9.3) were used. Specimens were tested under flexion (8 Nm) and extension (6 Nm) moments with compressive follower preloads of 0 N and 400 N in the following sequence: (i) intact, (ii) Charité TDR at L5-S1, (iii) simulated healed fusion at L5-S1 with Charité TDR at L4-L5. Segmental motion was measured optoelectronically. Motions between prosthesis end plates and core were visually assessed using sequential digital video-fluoroscopy over the full range of motion. Here we report on kinematics of 10 Charité TDRs: 5 at L5-S1 and 5 at L4-L5. RESULTS: Charité TDR increased the flexion-extension range of motion of lumbar segments (p<.05). At 400 N preload, the range of motion increased from intact values of 6.8+/-4.4 to 10.0+/-2.4 degrees at L5-S1 and from 7.0+/-2.6 to 10.8+/-2.9 degrees at L4-L5. Charité TDR increased segmental lordosis by 8.1+/-6.9 degrees at L5-S1 (p<.05) and 5.4+/-3.5 degrees at L4-L5 (p<.05). Four patterns of prosthesis component motion were noted: (1) angular motion only between the upper end plate and core, with little or no visual evidence of core translation (9 of 10 TDRs at 0 N preload and 5 of 10 TDRs at 400 N preload); (2) lift-off of upper prosthesis end plate from core or of core from lower end plate (observed in extension in 9 of 10 TDRs under 0 N preload only); (3) core entrapment, resulting in a locked core over a portion of the range of motion (observed in extension in 8 of 10 TDRs under 400 N preload); (4) angular motion between both the upper and lower end plates and core, with visual evidence of core translation (1 of 10 TDRs at 0 N preload, 5 of 10 TDRs at 400 N preload). The pattern of load-displacement curves was substantially changed under a physiologic preload in 8 of 10 TDRs; instead of a relatively gradual change in angle with changing moment application as seen for an intact segment, the TDR displayed regions of both relatively small and relatively large angular changes with gradual moment application. CONCLUSIONS: Charité TDR restored near normal quantity of flexion-extension range of motion under a constant physiologic preload; however, the quality of segmental motion differed from the intact case over the flexion-extension range. Whereas some TDRs showed visual evidence of core translation, the predominant angular motion within the prosthesis occurred between the upper end plate and the polyethylene core. Likely factors affecting the function of the Charité TDR include implant placement and orientation, intraoperative change in lordosis, and magnitude of physiologic compressive preload. Further work is needed to assess the effects of the prosthesis motion patterns identified in the study on the load sharing at the implanted level and polyethylene core wear.

Aged↗
PubMed2000

Chronic regional pain syndrome, type 1: Part II.

Chronic regional pain syndrome, type 1 (CRPS1) is a complex neurologic disease characterized by chronic, severe, burning pain; hyperesthesia; soft tissue swelling; dystrophy; hyperhidrosis; vasomotor and sudomotor instability; joint stiffness; and patchy osteoporosis. Five to six million people in the United States alone suffer from CRPS1. To date, CRPS1 is poorly understood and often is not recognized clinically. This syndrome requires early detection, pain control, and treatment in tandem with physical therapy to the affected area. Part I (published in September) discussed background information on CRPS1 and sympathetic nerve blocks. Part II focuses on the remaining treatment modalities (e.g., sympathectomy, physical therapy, stimulators, trigger point injections, acupuncture, tourniquet effects, placebo effects, amputation).

Chronic Disease↗
PubMed2000

Adaptative effects of loss of vision on upright undisturbed stance.

In order to evaluate the long term effect of blindness on an undisturbed postural task, seven blind individuals (BLI) were compared to twelve healthy individuals (REF) who were required to close their eyes. To this aim, centre of pressure (CP) trajectories were recorded through a force platform on which the subjects remained upright. Through a low-pass filter, the vertical projection of the centre of gravity (CG(v)) and consequently the difference CP-CG(v) were estimated. The former represents the controlled variable whilst the latter is assumed to express the resultant joint stiffness. A first analysis consisted in studying the frequency distribution of these motions. Increased mean amplitudes in both elementary motions and no difference between frequency distributions were observed for the BLI when compared to the REF group. These trajectories were then modelled as a fractional Brownian motion process in order to gain insight about the nature of the control mechanisms called into play and their spatio-temporal organisation. Moreover, the main characteristic observed in the BLI group is a decreased in CP-CG(v) motions, which, according to Winter's model, may be related to joint stiffness. In addition, reduced spatial transition point co-ordinates and more deterministic control mechanisms aimed at returning the estimated CG to an equilibrium point during the longest Deltat were observed. This phenomenon is more pronounced in the antero-posterior direction and also allows the blind subject to significantly diminish their CG sways. Finally, these features are discussed in relation to other similarly analysed investigations.

Adult↗
PubMed2003

Translational stiffness of the replaced shoulder joint.

Results after a total shoulder arthroplasty in rheumatoid patients are poor, indicated by loosening of especially the glenoid component, bad joint functionality and the possibility of a joint dislocation. The failure mechanisms behind this are multiple, including patient, surgical and design factors. These results must be improved. At present, the optimal geometrical prosthesis component design, focused on joint conformity and constraint, still has to be investigated. Proper understanding of the effect of geometrical design parameters on the theoretical relationship between joint translations and joint forces may contribute to improved designs. The main objective of this study is to theoretically describe this relationship and to investigate the joint translational stiffness, which can be used to investigate the effect of design parameters on joint motion. Joint translational stiffness is the gradient of the subluxation force with respect to the humeral head displacement. For this static analysis a potential field is introduced, as the result of a joint compressive force (muscle forces) and a subluxation force (external forces). The positive and negative stiffness during articulation inside and subluxation outside the glenoid cavity, lead to stable and unstable equilibrium joint positions, respectively. A most lateral position of the humeral head centre coincides with a zero subluxation force; at this position the humerus is dislocated and a restoring force is needed to relocate the humeral head. Joint conformity and compression force influence the joint translational stiffness during articulation inside the glenoid cavity, whereas during articulating outside the glenoid cavity this is influenced by the joint compression force and humeral radius of curvature. The glenoid radius of curvature influences the contact point and, in combination with the glenoid superior-inferior chord length, it also influences the constraintness angle, which influences the maximum allowable subluxation load to prevent a joint dislocation. This constraintness angle together with the joint conformity also influences maximum joint translations before articulation outside the glenoid cavity. Furthermore, the sign of the joint translational stiffness determines the stability of shoulder motion, which is stable and unstable if this stiffness is positive and negative, respectively.

Computer Simulation↗
PubMed1997

Adaptation of bone to physiological stimuli.

The ability of bone to alter its morphology in response to local physical stimuli is predicated upon the appropriate recruitment of bone cell populations. In turn, the ability to initiate cellular recruitment is influenced by numerous local and systemic factors. In this paper, we discuss data from three ongoing projects from our laboratory that examine how physiological processes influence adaptation and growth in the skeleton. In the first study, we recorded in vivo strains to quantify the locomotion-induced distribution of two parameters closely related to bone fluid flow strain rate and strain gradients. We found that the magnitude of these parameters (and thus the implied fluid flow) varies substantially within a given cross-section, and that while strain rate magnitude increases uniformly with elevated speed, strain gradients increase focally as gait speed is increased. Secondly, we examined the influence of vascular alterations on bone adaptation by assessing bone blood flow and bone mechanical properties in an in vivo model of trauma-induced joint laxity. A strong negative correlation (r2 = 0.8) was found between increased blood flow (76%) in the primary and secondary spongiosa and decreased stiffness (-34%) following 14 weeks of joint laxity. These data suggest that blood flow and/or vascular adaptation may interact closely with bone adaptation initiated by trauma. Thirdly, we examined the effect of a systemic influence upon skeletal health. After 4 weeks old rats were fed high fat-sucrose diets for 2 yr, their bone mechanical properties were significantly reduced. These changes were primarily due to interference with normal calcium absorption. In the aggregate, these studies emphasize the complexity of bone's normal physical environment, and also illustrate the potential interactions of local and systemic factors upon the process by which bone adapts to physical stimuli.

Adaptation, Physiological↗
PubMed1998

Avoiding pitfalls and complications in total shoulder arthroplasty.

To further minimize complications in the currently available arthroplasties and to improve results, the surgeon must understand all aspects of gleno-humeral joint replacement. Many of the important variables for successful results are under the surgeon's control and are discussed in this article.

Arthritis↗
PubMed2006

[Allograft-prosthesis composite arthroplasty for posttraumatic floating elbow].

Loss of bone stock in the elbow joint raises serious problems for reconstruction surgery. Total allograft-prosthesis composite arthroplasty is an attractive alternative to revision prosthesis and isolated osteoarticular allografts known to have many drawbacks. Use of this method is rather recent for revision procedures and tumor surgery and posttraumatic cases are rare (five reported cases). We report a case of posttraumatic floating elbow treated with this technique. At 75 months follow-up, the clinical result was excellent with the Mayo Clinic performance score at 100/100. Allograft-native bone fusion was complete and there were no complications, particularly no loosening. This composite technique is particularly well adapted for patients with major bone and joint loss. It can avoid the specific problems associated with each of the techniques used alone. The allograft reconstructs bone stock while the prosthetic component avoids the clinical expression of graft epiphyseal lysis.

Arthroplasty, Replacement↗
PubMed1995

Traumatic joint luxations in small animals.

Proper management of traumatic joint luxations in small animals requires complete assessment and treatment of life-threatening injuries, early joint reduction, stabilization of the joint, and early return to joint function. The methods of reduction vary with the joint involved but can often be achieved in a closed fashion. Joint stability is maintained by external coaptation or internal stabilization methods, depending on the degree of laxity present after reduction. Once joint stability is achieved, passive and active physical therapy is important to establish normal joint function. Reluxation, lameness, and degenerative joint disease are possible sequelae of traumatic joint luxations.

Animals↗
PubMed2003

Non-vascularized free toe phalanx transfers in congenital hand deformities--the Great Ormond Street experience.

Many options of varying complexity are available for the management of congenital short digits resulting from aphalangia in symbrachydactyly and constriction ring syndrome. We have used non-vascularized free toe phalanx transfers for these children when a vascularized toe transfer has been contraindicated. We describe our technique and experience with 22 children who underwent a total of 64 transfers of the proximal (35) or middle (29) toe phalanges (average 3 per child). The mean age at initial surgery was 15 months, and the mean follow-up was 5 years. Duration of time until epiphyseal closure could not be determined accurately, but total digital elongation averaged 6mm. Complications of this technique include joint instability, premature epiphyseal closure and, in one patient, infection and graft loss. Donor site deformity was determined according to measured growth deficit and toe function. This technique is a simple option for digital elongation and, if performed in the appropriate age group in short fingered and monodactylous subtypes of symbrachydactyly, has the potential to allow growth and function with minimal donor site deficit.

Bone Resorption↗
PubMed2000

Doppler imaging of vibrations as a tool for quantifying first tarsometatarsal joint stiffness.

OBJECTIVE: To assess whether first tarsometatarsal joint stiffness can be measured by Doppler imaging of vibrations and if so, to assess reference values. DESIGN: Repeated in vivo Doppler imaging of vibrations measurements at the first tarsometatarsal joint in healthy persons. BACKGROUND: Clinical hypermobility of the first tarsometatarsal joint is an important factor in a hallux valgus deformity. No objective and non-invasive test is available to quantify first tarsometatarsal joint mobility. Doppler imaging of vibrations, a technique recently developed to measure joint stiffness, might be an effective tool to quantify stiffness of this joint. METHODS: Vibrations were applied to the head of the first metatarsal in 46 feet of 23 healthy subjects and picked up by a transducer at both sides of the first tarsometatarsal joint. A pilot study was performed on three patients with hypermobility of the first tarsometatarsal joint. Measurements are expressed in threshold units related to colour Doppler imaging. RESULTS: The values of the threshold units were found to be very similar in healthy persons, with a good repeatibility; 95% of the healthy persons had a threshold unit below 3.4. No significant difference was found between the left and right foot, or between male and female subjects. Also there was no significant correlation with age or weight of the subjects. In the three patients with first tarsometatarsal hypermobility we found threshold units above 5. CONCLUSIONS: With Doppler imaging of vibrations first tarsometatarsal joint stiffness can be measured in healthy persons in a non-invasive and objective way. In a pilot study, three patients with first tarsometatarsal hypermobility showed lower stiffness values than the healthy subjects. Relevance This study presents a new method for quantification of first tarsometatarsal joint stiffness and provides reference values in healthy persons. First measurements on patients gave promising results to future use of this method for assessment of clinical hypermobility in hallux valgus patients.

Adolescent↗