Modification by oral doxycycline administration of articular cartilage breakdown in osteoarthritis

Oral administration of doxycycline has been shown to reduce the severity of articular cartilage breakdown in various animal models of osteoarthritis (OA). This disease modifying effect is associated with reductions in the levels of active and total collagenase and gelatinase in extracts of articular cartilage from the involved joint. These observations appear to justify a clinical trial of doxycycline, a readily available, inexpensive antimicrobial that has been used therapeutically in humans with OA for years with an excellent safety record.

Experimental assessment by high frequency ultrasound of articular cartilage thickness and osteoarthritic changes

OBJECTIVE

Osteoarthritis (OA) is characterized by progressive loss of articular cartilage in the involved joint. Accurate, reproducible measurement of the thickness of the cartilage in vivo, however, is difficult. Because development of an ultrasonic imaging device for intraarticular use is feasible and would permit acquisition of information that could complement the assessment of articular cartilage made at arthroscopy, we evaluated the efficacy of high frequency ultrasound in assessing the thickness and subsurface characteristics of normal and OA cartilage.

METHODS

Blocks of human femoral cartilage and subchondral bone and chips of cartilage alone were examined in vitro with an experimental 25 MHz pulse-echo ultrasound scanner that portrayed cross sections of the cartilage as B-mode images. The gross and histologic appearance of the articular surface was used to identify specimens of unblemished, normal cartilage and OA cartilage. The speed of sound in cartilage, determined from measurements of cartilage thickness and sound transmission, was related to its biochemical composition.

RESULTS

The speed of sound in normal cartilage (1658 +/- 185 m/s, n = 27) was greater than that in OA cartilage (1581 +/- 148 m/s, n = 40, p = 0.06), but was not related to the cartilage water content or the concentration of uronic acid or hydroxyproline. Images of normal cartilage showed a smooth echo band at the tissue surface with a hypoechoic matrix; in scans of fibrillated cartilage the width of this band was proportional to the depth of fibrillation (r = 0.78). Ultrasonic and histologic measurements of OA cartilage thickness were closely correlated (r = 0.87) and the mean coefficient of variation for repeated measurements was 2%.

CONCLUSION

High frequency ultrasonic images obtained in vitro provide highly accurate and reproducible measurements of the thickness and subsurface characteristics of normal and OA articular cartilage.

Serial kinematic analysis of the canine knee after L4-S1 dorsal root ganglionectomy: implications for the cruciate deficiency model of osteoarthritis

OBJECTIVE

To characterize knee movements before and after unilateral hindlimb deafferentation in dogs with stable joints.

METHODS

High speed cinematography and frame by frame analysis were used to analyze knee kinematics of 6 dogs serially for 26 weeks following L4-S1 dorsal root ganglionectomy, which was performed to deafferentate one hindlimb.

RESULTS

Overall knee movements were not reduced, but knee extension increased during most of the gait cycle. Few changes occurred in knee velocity, and none at touchdown or during weight acceptance.

CONCLUSION

We previously showed that unilateral hindlimb deafferentiation does not cause osteoarthritis or reduce ipsilateral peak vertical forces in dogs with stable knee joints over an observational period of 16 months. We now show that joint protection in the deafferented stable joint occurs, paradoxically, in the presence of increased knee extension. We conclude that whereas sensory nerves may limit knee extension during ambulation, the health of the joint is not dependent upon this "extension limiting" function.

Synthesis of a phenotypically abnormal type XI: type II collagen ratio by chondrocytes from canine osteoarthritic cartilage

Collagen synthesis by osteoarthritic cartilage from dogs that had undergone anterior cruciate ligament transection was measured in short-term organ cultures and chondrocyte suspension cultures. Slices of osteoarthritic cartilage from unstable knees 2, 6 or 12 weeks after anterior cruciate ligament transection converted approximately 10% of the total incorporated 14C-proline to 14C-hydroxyproline, while the value for cartilage from the contralateral knee or from knees of normal control dogs was generally less than 1%. The increase in collagen synthesis in the osteoarthritic cartilage was not related to the duration of knee instability, but was greater in grossly fibrillated cartilage than in the total pooled cartilage from the osteoarthritic joint. The collagen that was synthesized was predominantly type II, although some type XI and/or type V collagen was also synthesized. Chondrocytes isolated from osteoarthritic knee cartilage of dogs 12 weeks after anterior cruciate ligament transection showed changes in collagen synthesis similar to those seen in the cartilage organ cultures. As in the organ culture studies, type II collagen was the predominant species synthesized. When cell-associated collagen was considered, type II collagen accounted for 87+/-7% of the total collagen synthesized and retained by the osteoarthritic chondrocytes. The corresponding value for cells from the contralateral knee was 63+/-10%. Since the collagen fiber in articular cartilage is a heteropolymer of type II, type XI and type IX collagen, it is likely that the newly synthesized collagens in this model of osteoarthritis form fibers that are phenotypically different from those in normal articular cartilage.

A randomized, double blind, placebo controlled trial of intravenous loading with S-adenosylmethionine (SAM) followed by oral SAM therapy in patients with knee osteoarthritis

OBJECTIVE

We evaluated the effectiveness and rapidity of onset of S-adenosylmethionine (SAM), administered as daily intravenous boluses of 400 mg for 5 days, followed by oral tablets, 200 mg thrice daily for 23 days, versus a matching placebo regimen, in the treatment of 81 patients with symptomatic knee osteoarthritis (OA).

METHODS

The study was bicentric, randomized, double blinded, and placebo controlled. Patients underwent a 7-day washout of arthritis medications prior to initiation of this study treatment. Major outcome measures were the Stanford Health Assessment Questionnaire disability and pain scales, and supplemental visual analog scales for rest and walking pain.

RESULTS

At one site, patients had milder OA, the baseline characteristics of the treatment groups were well matched, and the SAM treated group showed significantly greater reduction in overall pain and rest pain (p < 0.05) than the placebo treated group. At the other site, the patients had more severe OA, randomization yielded markedly different treatment groups, and the response to treatment did not differ between groups. Onset of SAM effect was seen as early as 14 days after the start of treatment.

CONCLUSION

SAM may be an effective treatment for some patients with symptomatic knee OA, and merits further study. Intravenous loading before oral maintenance therapy may be advantageous.

Clinical rheumatology training in an uncertain future. Opinions of recent and current rheumatology fellows about an extended fellowship in musculoskeletal medicine

OBJECTIVE

To estimate among recent and current rheumatology fellows the appeal of a 3-year rheumatology fellowship emphasizing musculoskeletal medicine.

METHODS

A survey of 348 trainee members of the American College of Rheumatology during 1990-1993, by mailed questionnaire.

RESULTS

The response rate was 77.8% (n = 271). Both recent and current fellows indicated that they desired more experience in musculoskeletal medicine. Most notably, 50% of current fellows, and a significantly higher proportion of recent fellows (70%; P < 0.005), indicated that they would have opted for a 3-year fellowship in musculoskeletal medicine had one been available to them at the completion of their residency.

CONCLUSION

Expertise in musculoskeletal medicine is desired by a sufficient proportion of recent and current rheumatology fellows to warrant the investment in another year of training.

Serial kinematic analysis of the unstable knee after transection of the anterior cruciate ligament: temporal and angular changes in a canine model of osteoarthritis

Transection of the anterior cruciate ligament in the dog leads to osteoarthritis. This study defines the kinematic changes in the unstable knee after transection of the cruciate ligament (six dogs) and after a sham operation (four dogs). In the dogs that were anterior cruciate ligament-deficient (ACL-D), the duration of stance 1 week postoperatively decreased 38% from the preoperative value, but only a 4% decrease was seen at 6 weeks. The duration of double hindlimb support increased from 6 to 19% of the entire cycle 1 week after surgery but returned to the baseline value by 18 weeks. As the unstable limb contacted the treadmill belt, the initial flexion (yield) and subsequent extension (propulsive) phases were not evident or were markedly attenuated in every ACL-D dog throughout the 26-week period of observation. The angular velocity patterns were characterized by a slight extension velocity at touchdown (compared with a zero value preoperatively) and a decrease in the peak velocities (both flexion and extension) during the remainder of the stance phase. None of these changes was observed in the animals that had a sham operation. These data indicate that, in the dog, the nervous system compensates for instability of the knee by altering angular, but not temporal, parameters. The extension velocity at touchdown and the reduction in peak flexion velocity during the yield component of the stance phase may reduce the ability of the limb to absorb impact forces and lead to the development of osteoarthritis of the knee.(ABSTRACT TRUNCATED AT 250 WORDS)

Current practices for monitoring ocular toxicity related to hydroxychloroquine (Plaquenil) therapy

OBJECTIVE

Growing interest in aggressive early management of rheumatoid arthritis (RA) with hydroxychloroquine (alone or in combination with other immunomodulating drugs) is reason to review current practices for monitoring ocular toxicity in patients who take antimalarial therapy.

METHODS

We surveyed by mail all ophthalmologists and rheumatologists in the State of Indiana about their practices in this regard.

RESULTS

Twenty-nine of 31 rheumatologists (94%) responded. All but one recommended ophthalmologic examinations every 6 months and 41% would leave the choice of testing procedures to the ophthalmologist. Fifty percent had discontinued hydroxychloroquine because of a patient's failure to make and/or keep an appointment with the ophthalmologist. Of 213 ophthalmologists surveyed, 150 (70%) responded. Seventy-nine percent recommended semiannual examinations. Funduscopy, visual acuity, and color vision tests were reported to be performed routinely. Eleven of 13 retina specialists (85%), but only 25% of 127 general ophthalmologists, would obtain macular photographs (p < 0.001). Forty-two percent of general ophthalmologists, compared with 8% of retina specialists, would perform computerized perimetry (p < 0.001). Recognition of retinal hyperpigmentation as a classic sign was surprisingly low in both groups. Concurrent review of the medical records of 24 patients with RA or systemic lupus erythematosus showed extremely variable followup intervals for ophthalmologic examination; 7 of the 24 patients had no record of an ophthalmologic evaluation.

CONCLUSION

As interest in the early, aggressive management of RA continues to grow, significant education needs to be devoted to the monitoring and diagnosis of ocular toxicity of hydroxychloroquine by both rheumatologists and ophthalmologists.

Effect of sodium salicylate, aspirin, and ibuprofen on enzymes required by the chondrocyte for synthesis of chondroitin sulfate

OBJECTIVE

To examine the effects of sodium salicylate (Sal), aspirin [acetylsalicylic acid (ASA)] and ibuprofen (Ibu) (as the racemic mixture and the R- and S-enantiomers) on the activities of 2 enzymes involved in the biosynthesis of the hexose components of chondroitin sulfate (CS), i.e., UDP-glucose dehydrogenase (UDP-GD) and glutamine-fructose-6-phosphate-aminotransferase (GFAT), and of glucuronosyltransferase (GT), an enzyme involved in elongation of the nascent CS chain.

METHODS

UDP-GD and GT were obtained commercially. A homogenate of bovine articular cartilage chondrocytes was employed as a source of GFAT. In each case, enzymatic activity was measured spectrophotometrically.

RESULTS

Neither UDP-GD nor GFAT was inhibited by concentrations of Sal, ASA or Ibu that were achieved clinically in joint tissues (e.g., 1.0 mM Sal and ASA, 170 microM Ibu). In contrast, GT activity was inhibited by Sal and ASA in a concentration dependent fashion; at 1.0 mM, a concentration commonly reached in synovial fluid of patients treated with an antiinflammatory dose of the drug, GT activity in the presence of Sal and ASA was 54% (p = 0.001) and 75% (p = 0.05), respectively, of the control value. In contrast, a clinically relevant concentration of Ibu had no effect on GT activity.

CONCLUSION

Salicylates may suppress cartilage proteoglycan synthesis by inhibiting GT.

Finger joint force minimization in pianists using optimization techniques

A numerical optimization procedure was used to determine finger positions that minimize and maximize finger tendon and joint force objective functions during piano play. A biomechanical finger model for sagittal plane motion, based on finger anatomy, was used to investigate finger tendon tensions and joint reaction forces for finger positions used in playing the piano. For commonly used piano key strike positions, flexor and intrinsic muscle tendon tensions ranged from 0.7 to 3.2 times the fingertip key strike force, while resultant inter-joint compressive forces ranged from 2 to 7 times the magnitude of the fingertip force. In general, use of a curved finger position, with a large metacarpophalangeal joint flexion angle and a small proximal interphalangeal joint flexion angle, reduces flexor tendon tension and resultant finger joint force.

Compensation and decompensation of articular cartilage in osteoarthritis

Although contemporary descriptions of the pathology of osteoarthritis emphasize the loss of articular cartilage, in the earlier stages a marked increase in synthetic activity of the chondrocytes can lead to an increase in proteoglycan concentration and commonly, to cartilage hypertrophy. Thus, osteoarthritis exhibits a biphasic course, with an initial "compensatory" phase, during which homeostatic mechanisms may maintain a reasonable articular surface until the second phase, "decompensation" (joint failure), develops. Salicylates interfere with homeostatic repair mechanisms and can markedly truncate the compensatory phase. Polysulfated glycosaminoglycans and tetracyclines prolong the compensatory phase, thereby protecting against joint breakdown.

A longitudinal study of subchondral plate and trabecular bone in cruciate-deficient dogs with osteoarthritis followed up for 54 months

OBJECTIVE

To evaluate the sequence of changes in articular cartilage, trabecular bone, and subchondral plate in dogs with osteoarthritis (OA), 3 months, 18 months, and 54 months after anterior cruciate ligament transection (ACLT).

METHODS

Specimens of the medial tibial plateau were analyzed with microscopic computed tomography (micro-CT) at a resolution of 60 microns, and biochemical and morphologic changes in the femoral articular cartilage were assessed.

RESULTS

At 3 months and 18 months after ACLT, the articular cartilage in the unstable knee showed histologic changes typical of early OA and increased water content and uronic acid concentration; by 54 months, full-thickness ulceration had developed. Micro-CT analysis showed a loss of trabecular bone in the unstable knee, compared with the contralateral knee, at all time points. At both 18 and 54 months, the differences in trabecular thickness and surface-to-volume ratio were greater than at 3 months. Although the mean subchondral plate thickness, especially in the medial aspect of the medial tibial plateau, was greater in the OA knee than in the contralateral knee 18 months and 54 months after ACLT, these differences were not statistically significant; however, the difference was significantly greater at 54 months than at 3 months.

CONCLUSION

Thickening of the subchondral bone is not required for the development of cartilage changes of OA in this model. The bony changes that develop after ACLT, however, could result in abnormal transmission of stress to the overlying cartilage and thereby contribute to the progression of cartilage degeneration.

Sensory nerves only temporarily protect the unstable canine knee joint from osteoarthritis. Evidence that sensory nerves reprogram the central nervous system after cruciate ligament transection

OBJECTIVE

The slow rate at which articular cartilage degrades in dogs after transection of the anterior cruciate ligament (ACLT) has been attributed to capsular thickening and buttressing by osteophytes. We investigated the roles of the peripheral and central nervous systems in protecting knee joints with chronic ACL deficiency from breakdown.

METHODS

Five groups of dogs were studied; all were killed 72 weeks after left knee surgery. Group A had ACLT, group B had ACLT followed 52 weeks later by ipsilateral L4-S1 dorsal root ganglionectomy (DRG), group C had DRG followed 2 weeks later by ACLT, group D had sham DRG followed 2 weeks later by ACLT, and group E had DRG followed 2 weeks later by sham ACTL.

RESULTS

Group E dogs did not develop knee pathology. All cruciate-deficient knees were lax at the end of the study. The osteoarthritis (OA) that developed in groups A, B, and D was comparable (P > 0.05), and was significantly greater than that in group E (P < 0.05). Group C developed much more severe OA than any of the other groups (P < 0.05).

CONCLUSION

Ipsilateral sensory input is temporarily important in protecting the unstable joint from rapid breakdown. Over time, the central nervous system apparently acquires the ability to protect the unstable joint without continued ipsilateral sensory input.

Neurogenic factors in the etiopathogenesis of osteoarthritis

In this article we have tried to unify several different lines of evidence bearing on how neuromuscular mechanisms might contribute to the etiopathogenesis of OA. Several key points bear emphasis. (1) The neuromuscular system is both the greatest threat that the joint faces and the principal means by which joints are protected, because this system exercises the definitive influence on the spectrum of forces to which the joint is exposed. If muscle contraction is not properly coordinated, the joint will exceed its normal extreme of excursion and the loading of its cartilage will be excessive. This trauma will be manifest pathologically as OA. It follows that if the neuromuscular system cannot control the mechanical environment of the joint, the articular and periarticular tissues will break down even in the face of treatment with "chondroprotective" drugs. (2) Speculation about the role of sensation in joint protection is pointless unless sensory ablation influences the development of OA. (3) Only a small minority of patients with severe peripheral sensory neuropathy develop a Charcot joint, and a clear correlation between the development of a Charcot joint and the severity of the sensory neuropathy or the activity level of the patient has yet to be established. Until proved otherwise, it should not be assumed that ipsilateral sensation plays a role in protecting the stable joint from breakdown. (4) There have been surprisingly few animal experiments in which the effect of sensory nerve ablation on synovial joints has been examined. Although the results of the early studies are not entirely consistent, they suggest that extensive deafferentation of a limb does not necessarily lead to joint pathology in the absence of exogenous trauma or infection. Such studies should be repeated under carefully controlled conditions. (5) Recent work in dogs suggests that ipsilateral sensation is not important in protecting the stable joint from OA but is necessary to protect the unstable joint from rapid deterioration. Moreover, there is evidence that sensation is temporarily important in protecting the unstable joint but that the CNS eventually acquires the ability to protect the unstable joint even in the absence of ipsilateral sensory input.

Should osteoarthritis be treated with nonsteroidal anti-inflammatory drugs?

Numerous studies have demonstrated the efficacy of nonsteroidal anti-inflammatory drugs (NSAIDs) and their superiority to placebo as symptomatic treatment for osteoarthritis (OA). Unquestionably, use of NSAIDs has reduced joint pain and improved mobility for millions of patients with OA. This article explores the uncertainty that exists regarding the use of NSAIDs in the treatment of OA.

Improved training of house officers in a rheumatology consult service

This study examined whether the clinical environment could be used to increase internal medicine house officers' adoption of care recommendations taught in a didactic conference. Subjects were 11 internal medicine house officers who served 6-week rheumatology elective rotations. At the start of each of four rotation periods, house officers attended a 1-hour conference in which periarticular rheumatic disorders associated with knee pain (anserine bursitis, pseudothrombophlebitis) and shoulder pain (bicipital tendinitis) were discussed. All house officers also practiced physical examination techniques on anatomic models simulating the disorders. During alternate rotation periods, reminder sheets were appended to the records of arthritis patients with histories of chronic knee or shoulder pain. The frequency with which house officers followed conference recommendations was documented by direct observation (6 house officers in 17 encounters with reminders, 5 house officers in 30 encounters without reminders). Specific questioning about a recent history of knee or shoulder pain and the performance of four of five recommended physical examination maneuvers were increased significantly by reminder sheets in patients' charts (P < 0.05 for all). Although rheumatology faculty often have limited options available to increase the number of house officer trainees or to intensify clinical activity, qualitative improvements within existing logistic parameters are feasible by assuring that the clinical environment (e.g., patient records) contains salient cues that will prompt desired actions.

Prospective study of magnetic resonance imaging and SPECT bone scans in renal allograft recipients: evidence for a self-limited subclinical abnormality of the hip

We recently reported that typical abnormalities of avascular necrosis (AVN) in magnetic resonance images (MRI) of the hips of asymptomatic renal transplant recipients whose plain radiographs are normal may improve spontaneously and even disappear completely. We present the results of serial bone scans, most of which were performed with single-photon emission computed tomography obtained over periods as long as 24 mo after transplantation in 72 of these patients. Three paired imaging studies (i.e., MR and bone scan performed within 30 days of each other) were available for each of these patients. In three patients, both the MR images and the bone scans showed changes consistent with bilateral AVN within 4 mo after transplantation. All three patients developed hip pain which was bilateral in two and unilateral in one. Two patients (three hips) required surgical intervention at which time AVN was found on pathologic examination of all three hips. None of the remaining 69 patients developed hip pain during the study. However, in nine patients whose MR studies were consistently normal, at least one bone scan was abnormal (13 hips). The presence of AVN was pathologically confirmed in each of the hips subjected to surgery. Where the imaging findings were identical to those in the asymptomatic patients as well as those in whom the imaging abnormality regressed, we suggest that the subclinical imaging abnormalities represent mild AVN, which is reversible in some cases. Since the process was identified in 10 hips by MRI and in 13 hips by bone scan, both studies are needed to detect subclinical AVN. This may be important if treatment of subclinical disease is clearly shown to prevent progression to symptomatic AVN.

Should nonsteroidal anti-inflammatory drugs be used to treat osteoarthritis?

Millions of individuals with osteoarthritis have experienced relief of joint pain and improvement in mobility as a result of taking nonsteroidal anti-inflammatory drugs (NSAIDs). These agents are currently considered the drug of choice for treatment of osteoarthritis (OA). Despite their efficacy and nearly universal use in OA, the role of NSAIDs in managing this disorder recently has become controversial. This article reviews the issues that lie at the heart of the problem.