Therapeutic strategies distinguish community based primary care physicians from rheumatologists in the management of osteoarthritis

Using an osteoarthritis (OA) case study, we described the drug therapy that primary care physicians prescribe for uncomplicated OA of the hip, and for OA complicated by a history of gastropathy or renal insufficiency. To produce "gold standard" criteria against which to interpret previous results, the same instrument was administered to 126 rheumatologists selected at random from the membership of the American College of Rheumatology. Virtually all rheumatologists prescribed nonsteroidal antiinflammatory drugs (NSAID); 76% specified doses large enough to have significant antiinflammatory effects. In contrast, 65% of the primary care physicians recommended NSAID therapy in a suboptimal antiinflammatory dose (p = 0.055 for the rheumatologist-primary care physician difference). For OA complicated by a history of either gastropathy or renal insufficiency, rheumatologists were more likely than primary care physicians to adopt a therapeutic strategy that did not inhibit prostaglandin synthesis (p < 0.001 for both). Differences also were noted in the ancillary therapies employed by the 2 groups for managing uncomplicated OA. Educational interactions between rheumatologists and primary care physicians could benefit by recognition of the differing perspectives on NSAID dosing, the avoidance of NSAID induced side effects, and ancillary therapies that appear to differentiate subspecialists and generalists.

Treatment of knee osteoarthritis: relationship of clinical features of joint inflammation to the response to a nonsteroidal antiinflammatory drug or pure analgesic

Our randomized double blinded comparison of acetaminophen versus analgesic and antiinflammatory doses of ibuprofen in the treatment of 182 subjects with knee osteoarthritis (OA) systematically evaluated soft tissue tenderness and joint swelling. Improvement in these signs of joint inflammation was associated with lessening of disability (p = 0.02), and reduction in rest pain (p = 0.07), but not with the drug treatment regimen. Thus, joint tenderness and swelling, presumptive evidence of synovitis, may not be a priori indications for use of an antiinflammatory drug, or predict greater responsiveness to treatment with an antiinflammatory drug than to a pure analgesic, in symptomatic treatment of patients with knee OA.

Reduction of the severity of canine osteoarthritis by prophylactic treatment with oral doxycycline

OBJECTIVE

In vitro studies have indicated that levels of neutral metalloproteinases in osteoarthritic (OA) cartilage are elevated and that doxycycline (doxy) inhibits collagenolytic and gelatinolytic activity in extracts of OA cartilage. The purpose of the present study was to test the effect of oral doxy administration on the severity of cartilage degeneration in OA.

METHODS

OA was induced in 12 adult mongrel dogs by transection of the anterior cruciate ligament (ACL) 2 weeks after dorsal root ganglionectomy. Six dogs received doxy orally from the day after ACL transection until they were killed 8 weeks later; the other 6 served as untreated OA controls.

RESULTS

The unstable knee of each untreated dog exhibited extensive full-thickness cartilage ulceration of the medial femoral condyle. In sharp contrast, cartilage on the distal aspect of the femoral condyle of the unstable knee was grossly normal in 2 doxy-treated dogs, and exhibited only thinning and/or surface irregularity in the others. Degenerative cartilage lesions on the medial trochlear ridge, superficial fibrillation of the medial tibial plateau, and osteophytosis were, however, unaffected by doxy treatment. Collagenolytic activity and gelatinolytic activity in cartilage extracts from OA knees of untreated dogs were 5-fold and 4-fold greater, respectively, than in extracts from dogs given doxy.

CONCLUSION

Prophylactic administration of doxy markedly reduced the severity of OA in weight-bearing regions of the medial femoral condyle. It remains to be determined whether administration of doxy after OA changes have developed is also effective.

Prevalence of cartilage shards in synovium and their association with synovitis in patients with early and endstage osteoarthritis

It has been suggested that incorporation of shards of fibrillated cartilage into the synovium is a cause of synovitis in osteoarthritis (OA). We examined the prevalence with which fragments of cartilage are seen in synovium, and their association with synovitis, in patients with endstage OA and early OA of the knee. Samples of synovium were obtained from 12 patients with endstage OA who were undergoing knee joint replacement and 30 with only mild/moderate radiographic changes of OA who exhibited articular cartilage changes of OA at arthroscopy. The presence of cartilage shards was sought in synovium from the medial and lateral tibiofemoral compartments and the suprapatellar pouch of each patient. Comparable volumes of the synovial lining from patients with endstage and early OA were examined, and tissue mononuclear cell infiltration was graded as an indicator of synovitis. Cartilage shards were seen in synovium from 7 of 12 patients with endstage OA, all of whom had synovitis. No topographic relationship was found between shards and mononuclear cell infiltration. In contrast, cartilage fragments were not seen in synovium from any of the 30 patients with early OA, although 9 of them had full thickness cartilage ulcers and 17 had evidence of synovitis.

A radiographic comparison of erosive osteoarthritis and idiopathic nodal osteoarthritis

Clinical, radiographic and histologic features suggest that inflammation is central to the pathogenesis of erosive osteoarthritis (OA). Since mediators of inflammation may activate osteoclasts and stimulate release of metalloproteinases in joint cartilage, we hypothesized that patients with erosive OA may have more joint space narrowing and less proliferative bone response (osteophytes, sclerosis) than those with idiopathic nodal OA. Hand radiographs of 33 patients with erosive OA and 33 age and sex matched patients with nodal OA were evaluated for prevalence and severity of joint space narrowing, osteophytes, subchondral sclerosis, subchondral cysts, erosions and subchondral collapse. While the prevalence and severity of OA was greater at each joint in erosive OA than in nodal OA, significant differences (p less than 0.05) were confined largely to the interphalangeal joints. Among patients with erosive OA, radiographic features of OA were more severe in joints with erosive changes than in joints that did not show erosive change (p less than 0.01 in most cases). Notably, when joints with erosive change were excluded, only joint space narrowing was more severe in patients with erosive OA than in the corresponding joints of patients with nodal OA (p less than 0.001). Our analysis did not support the hypothesis that inflammatory mediators modify chondro or osteoneogenesis in erosive OA.

Reduction of joint pain in patients with knee osteoarthritis who have received monthly telephone calls from lay personnel and whose medical treatment regimens have remained stable

OBJECTIVE

We previously reported that monthly telephone contact by lay personnel, to promote self-care for patients with osteoarthritis (OA), was associated with improved joint pain and physical function after 1 year of followup. The present study was a secondary analysis to determine whether improvement was contingent on intensified medical treatment.

METHODS

We reanalyzed control/treatment group differences in all 40 subjects with radiographically confirmed knee OA who had had no changes in antirheumatic drug therapy or institution of physical therapy during the period of observation.

RESULTS

Group differences in measured pain remained significant (effect size [ES] = 0.65 SD, P less than 0.01). The same trend was observed for physical function (ES = 0.53 SD, P not significant).

CONCLUSION

The findings in this reanalysis suggest that periodic telephone support interventions are effective enough to be regarded as an adjunctive treatment for OA.

Impairment of osteophyte formation in hyperglycemic patients with type II diabetes mellitus and knee osteoarthritis

OBJECTIVE

Since insulin is a potent growth factor for connective tissue, the present study was designed to investigate whether radiographic features of knee osteoarthritis (OA) in patients with poorly controlled, insulin-resistant type II diabetes mellitus differ from those in nondiabetic controls with knee OA.

METHODS

Radiographs from 25 female patients with diabetes and knee OA were compared with those from 48 female controls who were similar with respect to age, weight, and duration of OA symptoms.

RESULTS

Although the 2 groups were similar with respect to the frequency and severity of joint space narrowing, subchondral sclerosis, and geodes, osteophytes were less common in the patients with diabetes (P = 0.044), and spurring, when present, tended to be "marked" less often in the diabetic patients than in the controls.

CONCLUSION

The data suggest that diminished availability of insulin at the cellular level or diabetic microvascular disease attenuates the chondro- and osteogenesis required for osteophyte formation in the joints of patients with OA.

Neurogenic acceleration of osteoarthrosis. The effects of previous neurectomy of the articular nerves on the development of osteoarthrosis after transection of the anterior cruciate ligament in dogs

The development of osteoarthrosis in unstable knee joints of dogs after transection of the anterior cruciate ligament is greatly accelerated when the afferent nerve fibers from the ipsilateral hindlimb have been interrupted by dorsal root ganglionectomy before transection. The purpose of the current study was to determine whether partial loss of the afferent fibers from the knee joints of dogs, accomplished by neurectomy of the primary articular nerves before transection of the ligament, also accelerates the development of osteoarthrosis. Osteoarthrosis did not develop in dogs that had had transection of the medial, posterior, and lateral articular nerves to the left knee joint but had an intact anterior cruciate ligament. Osteoarthrosis developed in all dogs that had had transection of the anterior cruciate ligament. However, the osteoarthrotic lesions, as gauged by histological and macroscopic criteria, were more frequent and severe in dogs that had had neurectomy before transection than in those that had intact sensory nerves and an unstable joint (p less than or equal to 0.05). A subchondral fracture occurred in three dogs that had had neurectomy and had an unstable joint but in none of the dogs that had intact sensory nerves and an unstable joint.

Structure-function relationships in indium-111 radioimmunoconjugates

Conjugates formed by reaction of monoclonal antibody B72.3 with benzyl isothiocyanate derivatives of four amino polycarboxylate chelators (NTA, EGTA, EDTA, DTPA) were labeled with indium-111 and administered iv to athymic mice bearing antigen-positive (LS174T) and antigen-negative (A375) human tumor xenografts. Conjugate immunoreactivities, antibody dose, and xenograft size were controlled, so that the effects of varying chelate structure could be evaluated under conditions where immunological and physiological factors were effectively held constant. Tissue distribution and excretion of the radiometal at 24 and 48 h postinjection were shown to correlate directly with chelate thermodynamic stability (NTA less than EGTA less than EDTA less than DPTA). Radioactivity levels in the blood and the LS174T xenograft increased, while kidney levels and excretion levels decreased, with increasing chelate stability. The kidney was the only normal organ that accumulated non-antibody-bound 111In, uptake of radioactivity into all other tissues, and in particular the liver, being unaffected by changes in chelate structure. Mean transferrin saturation in the tumor-bearing athymic mice was found to be 65%. It is proposed that uptake of free 111In by serum transferrin is precluded in this model, leading to the observed renal localization of unbound label. Kidney:blood and kidney:LS174T activity ratios at 48 h postinjection provided the most sensitive indices of conjugate instability in vivo, spanning 50- and 20-fold ranges, respectively, between the least stable and the most stable conjugate. It is concluded that this antigen/antibody system and mouse model are well-suited to structure-function studies of immunoglobulin labels.

Hypothesis: can type IX collagen "glue" together intersecting type II fibers in articular cartilage matrix? A proposed mechanism

Type IX collagen is crosslinked to the surface of type II collagen molecules, and has been proposed as the glue that binds the collagen network of cartilage matrix. However, there is as yet no evidence that the crosslinks that have been described to date provide interfibrillar connections, and the only mechanism proposed for such connections between intersecting fibers is unlikely on stereochemical grounds. We propose that both type IX collagen and an intermediary molecule are necessary for network stabilization and that proteoglycans are likely candidates for the role of intermediary.

Correlation of serum concentrations of ibuprofen stereoisomers with clinical response in the treatment of hip and knee osteoarthritis

Stereoselective pharmacokinetic measurements of the active enantiomer, S-ibuprofen, were correlated with clinical response in 45 participants in a randomized double blinded 4 week comparison of ibuprofen, 1200 or 2400 mg/day, for treatment of hip or knee osteoarthritis. Ibuprofen dose correlated with S-ibuprofen area under the serum concentration curve (AUC), trough and average concentration, but not with clinical outcome. AUC of S-ibuprofen correlated with improvement in disability, rest pain and in the physician's global assessment (p = 0.02, 0.08, and 0.10, respectively), and negatively with the subject's weight and creatinine clearance (p = 0.09 and 0.07, respectively). Some individual variation in responsiveness to ibuprofen (and other nonsteroidal antiinflammatory drugs) may be attributed to pharmacokinetic differences.

Low dose prednisone treatment does not reduce the severity of osteoarthritis in dogs after anterior cruciate ligament transection

It was reported recently that oral administration of prednisone, 0.3 mg/kg/day, decreased osteophyte size and cartilage ulceration in dogs with osteoarthritis (OA) produced by "stab" transection of the anterior cruciate ligament. Since this dose would be equivalent to 17 mg/day for a 70-kg human, our study was performed to determine whether a lower, clinically more realistic, dose of prednisone also had ameliorating effects on OA in the canine model. Following arthrotomy and transection of the anterior cruciate ligament 10 adult mongrel dogs were each given prednisone, 0.1 mg/kg/day, begun either 0, 2, or 4 weeks after arthrotomy and continued until sacrifice 12 weeks after surgery; 7 others underwent the identical surgical procedure but received no prednisone and served as OA controls. No differences were noted between dogs treated with prednisone and the controls with respect to size or extent of osteophytes, severity of synovial inflammation, morphologic changes of OA in articular cartilage, or in vitro synthesis of glycosaminoglycans. Increases in cartilage thickness in the OA knee were similar in the 2 groups, as were increases in H2O content and uronic acid concentration. Regardless of the interval between arthrotomy and start of treatment, the low dose of prednisone used here did not reduce the severity of OA in this model.

Transection of the anterior cruciate ligament in the dog: a model of osteoarthritis

Study of the early stages of osteoarthritis (OA) in humans presents numerous difficulties, since the patient commonly does not seek medical attention until pathologic changes are far advanced and articular cartilage has already been extensively lost. Investigators have, therefore, used animal models to obtain information about the early changes in articular cartilage, bone, and synovium. Among the most widely studied of these models is the cruciate-deficient dog. This report validates the cruciate-deficient dog as a model of progressive OA and emphasizes that, before full-thickness loss of articular cartilage, OA is marked by a phase of cartilage hypertrophy associated with a striking increase in synthesis of matrix macromolecules by the chondrocyte (compensatory repair). It reviews evidence that some nonsteroidal antiinflammatory drugs (NSAIDs) and deafferentation of the unstable limb may accelerate cartilage loss in OA, and examines the relationship of synovitis and of changes in subchondral bone to the changes in articular cartilage.

Osteoarthritic changes in canine articular cartilage, subchondral bone, and synovium fifty-four months after transection of the anterior cruciate ligament

Anterior cruciate ligament transection (ACLT) in the dog results in osteophyte formation and in morphologic, metabolic, biochemical, and biomechanical changes in the articular cartilage of the unstable knee that mimic those of human osteoarthritis (OA). However, in dogs studied up to 2 years after ACLT, the changes have appeared to be self-limiting, which has led to the suggestion that this is a model of cartilage damage and repair, rather than of OA. To ascertain whether changes in articular cartilage and subchondral bone of dogs subjected to ACLT lead to progressive changes of OA, we studied 3 dogs for 54 months after ACLT. Arthrotomy was performed in the dogs to visualize and then transect the anterior cruciate ligament. When the dogs were killed, full-thickness ulceration of the articular cartilage was seen on the medial femoral condyle and tibial plateau of the unstable knee, while cartilage in other regions was thicker than that of the contralateral knee, consistent with hypertrophic cartilage repair. Synovial infiltration by mononuclear cells was not more severe than that seen in dogs killed at earlier intervals after ACLT, although gross fibrotic thickening of the capsule was apparent in each dog. Histomorphometric studies revealed a marked increase in subchondral bone volume and active bone formation. These findings show that the changes that develop in the canine knee joint after ACLT are progressive and are unambiguously those of OA.

Radiographic grading of the severity of knee osteoarthritis: relation of the Kellgren and Lawrence grade to a grade based on joint space narrowing, and correlation with arthroscopic evidence of articular cartilage degeneration

We examined standing knee radiographs of 92 patients who had chronic knee pain and radiographic evidence of mild or moderate osteoarthritis (OA) according to the Kellgren and Lawrence (K/L) criteria. Because the K/L criteria overemphasize osteophytosis relative to joint space narrowing (JSN), we graded OA severity also with a scoring system that placed greater emphasis on JSN than on osteophytes. In each case, the articular cartilage was visualized directly at arthroscopy. Of 17 patients whose radiographic findings were normal by both the K/L criteria and our JSN-weighted criteria, 7 had advanced tibiofemoral and/or patellofemoral compartment changes of OA seen at arthroscopy, emphasizing the insensitivity of the radiograph for detecting early articular cartilage loss. In addition, tibiofemoral JSN was common in the presence of normal articular cartilage. The JSN-weighted scale provided no advantage over the K/L criteria for assessing the severity of articular cartilage changes of OA.

The therapeutic approaches of community based primary care practitioners to osteoarthritis of the hip in an elderly patient

Predispositions to prescribe a pure analgesic, a cyclooxygenase inhibiting nonsteroidal antiinflammatory drug (NSAID) or a nonacetylated salicylate for a fictitious, uncomplicated case of osteoarthritis (OA) were surveyed in a sample of 152 community based primary care practitioners who had been characterized with respect to medical education and practice characteristics. Only 2 respondents (1%) prescribed a pure analgesic; 35% prescribed subantiinflammatory doses of cyclooxygenase inhibiting NSAID. The remainder (64%) recommended nonacetylated salicylates and cyclooxygenase inhibiting NSAID in doses large enough to achieve an antiinflammatory effect. Past participants in postgraduate rheumatology electives prescribed more costly regimens than those who had not participated (p = 0.05). When the case was altered to include a history of previous peptic ulcer, 44% chose cyclooxygenase inhibiting NSAID with adjunctive prophylaxis against NSAID induced gastropathy (e.g., misoprostol). When the complication was changed to renal insufficiency, recommendations for sulindac increased 3-fold over those for the uncomplicated case (34 vs 11%), and were most common among more recent medical school graduates and past participants in rheumatology electives (p less than 0.05 for both). The potential effects of educational and practice variables on the therapeutic strategies and costs of OA care in the community merit further systematic study.

Doxycycline inhibits type XI collagenolytic activity of extracts from human osteoarthritic cartilage and of gelatinase

Doxycycline was shown to inhibit digestion of exogenous type XI collagen by homogenates of human osteoarthritic cartilage in vitro. On SDS-PAGE, the cleavage products generated by cartilage extracts were larger and less abundant, indicating less complete cleavage, when doxycycline (10 or 30 microM) was added to the samples. The inhibitory effect was concentration dependent. Purified gelatinase from canine kidney epithelial cells, which also digests type XI collagen, was inhibited in a similar manner by doxycycline. If tetracyclines inhibit this metalloproteinase activity in articular cartilage in vivo, they could modify cartilage breakdown in osteoarthritis.

Comparison of an antiinflammatory dose of ibuprofen, an analgesic dose of ibuprofen, and acetaminophen in the treatment of patients with osteoarthritis of the knee

BACKGROUND

The optimal short-term, symptomatic therapy for osteoarthritis of the knee has not been fully determined. Accordingly, we compared the efficacy of a nonsteroidal antiinflammatory drug, ibuprofen, given in either an antiinflammatory dose (high dose) or an analgesic dose (low dose), with that of acetaminophen, a pure analgesic.

METHODS

In a randomized, double-blind trial, 184 patients with chronic knee pain due to osteoarthritis were given either 2400 or 1200 mg of ibuprofen per day or 4000 mg of acetaminophen per day. They were evaluated after a washout period of three to seven days before the beginning of the study, and again after four weeks of treatment. The major measures of outcome included scores on the pain and disability scales of the Stanford Health Assessment Questionnaire (range of possible scores, 0 to 3), scores on the visual-analogue scales for pain at rest and pain while walking, the time needed to walk 50 ft (15 m), and the physician's global assessment of the patient's arthritis.

RESULTS

Seventy-eight percent of the patients completed four weeks of therapy. No significant differences were noted among the three treatment groups with respect to failure to complete the trial because of noncompliance or adverse events. All three groups had improvement in all major outcome variables, and the groups did not differ significantly in the magnitude of improvement in most variables. The mean improvement (change) in the scores on the pain scale of the Health Assessment Questionnaire was 0.33 with acetaminophen (95 percent confidence interval, 0.14 to 0.52), 0.30 with the low dose of ibuprofen (95 percent confidence interval, 0.09 to 0.51), and 0.35 with the high dose of ibuprofen (95 percent confidence interval, 0.13 to 0.57). Side effects were minor and similar in all three groups.

CONCLUSIONS

In short-term, symptomatic treatment of osteoarthritis of the knee, the efficacy of acetaminophen was similar to that of ibuprofen, whether the latter was administered in an analgesic or an antiinflammatory dose.

Apparent avascular necrosis of the hip: appearance and spontaneous resolution of MR findings in renal allograft recipients

The sensitivity of magnetic resonance (MR) imaging in the detection of avascular necrosis (AVN) of the hip and natural history of the MR findings were determined prospectively in renal allograft recipients, a group at risk for development of the disease. One hundred four patients were studied up to 24 months after transplantation. In 25 hips in 14 patients, MR findings were consistent with AVN. Pain developed in seven hips in four patients; in each hip, the MR images showed abnormality before the onset of symptoms. Plain radiographs showed abnormality in all hips that became painful; however, the plain radiographs of 17 of 18 asymptomatic hips in which MR imaging showed evidence of AVN showed no abnormality over a mean follow-up period of 16 months. All MR lesions in the symptomatic hips were larger than those in the asymptomatic cohort. MR lesions in seven hips (in five asymptomatic patients) regressed in size; in six hips, the MR images returned to normal. The findings suggest that some patients with MR evidence of AVN of the hip have spontaneous improvement.

The presence of cartilage matrix glycoprotein in serum as determined by immunolocation analysis is not a sensitive indicator of "early" osteoarthritis of the knee

Widespread effort is being devoted to the search for a serologic "marker" that could aid in the early diagnosis of osteoarthritis and in following the progression of the disease in response to treatment. It is obvious that such a marker would have its greatest utility in patients with mild or early osteoarthritis. CMGP is a disulfide-bonded 550,000 dalton cartilage matrix glycoprotein with a half-life of only 48 to 72 hours that has been found, through immunolocation analysis, in the serum of dogs with experimentally induced osteoarthritis and in the synovial fluid of patients with osteoarthritis but not other types of arthritis. To determine whether detection of CMGP in serum might be of value in identifying patients with "early" osteoarthritis, we examined serum samples from 26 patients with knee pain who had articular cartilage lesions of osteoarthritis at arthroscopy but whose knee radiographs were normal or showed only mild or moderate osteoarthritis. CMGP was identified by immunolocation analysis with specific antibodies. Eleven patients (42%) were seropositive for CMGP. In two, the degenerative cartilage lesions visualized at arthroscopy were mild (grade 2); in the other nine they were more severe (grade 3 or 4). However, 10 of the 15 seronegative patients also had grade 3 or 4 cartilage degeneration. Thus, this serum assay for CMGP was often negative in this group of patients in the presence of well-defined cartilage degeneration.

Relationship between arthroscopic evidence of cartilage damage and radiographic evidence of joint space narrowing in early osteoarthritis of the knee

We examined the relationship between articular cartilage degeneration, as visualized arthroscopically, and joint space narrowing (JSN) in standing anteroposterior knee radiographs of 161 patients with chronic knee pain. The majority of these patients had radiographic findings of mild osteoarthritis. Twenty-five (33%) of the 76 patients in the series whose radiographs showed tibiofemoral JSN had grossly normal articular cartilage in both tibiofemoral compartments at arthroscopy (false-positive). The specificity of medial JSN for the presence of medial compartment articular cartilage degeneration was 0.61, i.e., only 61% of patients with normal (grade 0) medial compartment cartilage had a normal medial joint space. Of 22 patients with greater than 50% medial JSN, 9 (41%) had normal articular cartilage in the medial compartment at arthroscopy. Of 6 patients with greater than 50% lateral JSN, 3 (50%) had normal lateral compartment articular cartilage at arthroscopy. Among 36 patients with greater than 25% JSN who had neither medial nor lateral compartment articular cartilage degeneration, JSN was associated with articular cartilage degeneration in the patellofemoral compartment in 8 (22%), with meniscus degeneration in 18 (50%), and with both in 8 (22%). Thus, in these patients with chronic knee pain, radiographic evidence of JSN in the tibiofemoral compartment did not permit confident prediction of the status of the articular cartilage.

The effect of intertrabecular fluid on femoral head mechanics

The effect of intraosseous fluid on the mechanical characteristics of bone is unclear. To determine the potential effects of alteration in the fluid boundary conditions of the femoral head, a decompression procedure was performed. The stiffness of femoral heads from normal adult mongrel dogs was measured after the heads were subjected to a physiologic mechanical load. When the fluid boundary conditions were altered by drilling the femoral neck, femoral head stiffness was reduced by more than 30% (p = 0.045). Refilling of the femoral specimen with saline restored the stiffness to the baseline value. These observations demonstrate that in vitro changes of fluid boundary conditions can alter the mechanical integrity of the femoral head. Alteration in osseous fluid boundary conditions in vivo could affect joint integrity and be of pathogenetic significance in joint disease.

Hypertrophic repair of canine articular cartilage in osteoarthritis after anterior cruciate ligament transection

Transection of the anterior cruciate ligament in the dog is used frequently to produce a model of osteoarthritis (OA). Although it results in metabolic, biochemical, biomechanical and morphological changes in the articular cartilage of the unstable knee which resemble those in human OA, it rarely results in full thickness cartilage loss. The lack of progression of the cartilage lesions in this model has generally been attributed to stabilization of the joint by osteophytes and capsular fibrosis which develop following transection of the ligament. In our study transection of the anterior cruciate ligament of adult foxhounds and mongrels resulted in a progressive increase in the amount of articular cartilage in the unstable knee. In articular cartilage from the medial femoral condyle of the unstable knee the total amount of proteoglycan, as assessed by hexuronic acid analysis, and, often, the proteoglycan concentration were increased. Furthermore, the rate of proteoglycan synthesis was commonly elevated, in comparison with that from the contralateral knee. Thus, in these animals knee instability did not lead to loss of cartilage but to an active synthetic response by the chondrocytes resulting in hypertrophic cartilage repair which was sustained for up to 64 weeks of observation.

Anterior (cranial) cruciate ligament transection in the dog: a bona fide model of osteoarthritis, not merely of cartilage injury and repair

To help elucidate the longterm outcome in the unstable knees of dogs that have undergone anterior cruciate ligament (ACL) transection, conventional radiography, gait analysis and magnetic resonance imaging (MRI) were performed serially on 3 dogs over a 45-month period after ACL transection. Gait analysis showed that vertical forces generated by the cruciate deficient leg were smaller than those produced by the contralateral leg, but the decrease in loading was not progressive and clinical findings did not suggest that the dogs developed pain in the unstable limb. Despite progressive osteophytosis and subchondral sclerosis, as seen on plain radiographs, MRI demonstrated that articular cartilage in the unstable knee was thicker than that in the contralateral knee 36 months after ACL transection. Nine months later, however, striking focal loss of articular cartilage was seen in the unstable knee of each dog. Our study, which provides the first longterm observations of the changes in the unstable knee after ACL transection, shows that they represent progressive osteoarthritis and emphasizes that a prolonged phase of cartilage hypertrophy may precede the stage of cartilage breakdown.

The mechanism of action of nonsteroidal antiinflammatory drugs

Several nonsteroidal antiinflammatory drugs (NSAID), although not all, inhibit proteoglycan synthesis by normal articular cartilage in vitro; the inhibitory effect is much more marked in osteoarthritic cartilage. For salicylates, in vivo data support the in vitro findings; degeneration of articular cartilage in animal models is accelerated by oral administration of aspirin. While it has been suggested that NSAID may be "chondroprotective," no clinical studies exist to support the view that NSAID favorably influence progression of joint degeneration in man, nor do well designed controlled studies show that NSAID are superior to a pure analgesic, e.g., acetaminophen, in treatment of symptoms of osteoarthritis.

Cleavage of type XI collagen fibers by gelatinase and by extracts of osteoarthritic canine cartilage

Gelatinase (matrix metalloproteinase 2) purified from culture medium of MDCK cells by affinity chromatography on gelatin-sepharose was tested against type XI collagen. The purified enzyme-digested native type XI collagen in solution, and as reconstituted fibers, at 30, 34, and 37 degrees C. Both substrates yielded the same digestion products, as characterized by SDS-polyacrylamide gel electrophoresis, but the soluble collagen was cleaved at a higher rate. The first major product seen was an 87-kDa peptide, which was usually associated with one or two peptides migrating between it and alpha 3(XI). With time, a second group of 3 peptides appeared at 78, 75, and 73 kDa. After continued digestion, a third group of peptides was detected with prominent 69- and 67-kDa peptides and minor peptides at 71, 65, and 62 kDa. In overnight (20 hour) digestions, the 60-kDa digestion product accumulated and most of the larger digestion products could no longer be detected. Minor products at 71, 55, and 50 kDa were also noted in these limited digestions. Under the same conditions, denatured type XI was digested to fragments smaller than 13.5 kDa. The enzyme was inhibited by 1,10-phenanthroline or EDTA. Two purified components of cartilage matrix, type II collagen and proteoglycan subunit, as well as crude cartilage homogenates, were not effective inhibitors of the purified enzyme. Similar activity was extracted from canine articular cartilage, and the activity was much stronger in cartilage from osteoarthritic joints than from control joints.

Characterization of antibody-chelator conjugates: determination of chelator content by terbium fluorescence titration

Fluorescence titrations were performed by adding varying mole ratios of terbium(III) to antibody conjugates formed by benzyl isothiocyanate derivatives of three different polyaminopolycarboxylate chelators (NTA, EDTA, and DTPA) and the results compared to values for average chelator content obtained by cobalt-57 binding assays. For two different murine monoclonal antibodies, the average chelator content obtained by terbium fluorescence titration correlated closely with that measured by the cobalt-57 binding assay. It is concluded that lanthanide fluorescence titrations provide a useful alternative to radiometal binding assays for the determination of chelator content in protein-chelator conjugates.

A behaviorally effective model for training of general health professionals by a rheumatology team

This project evaluated a model for inservice arthritis education based in part on principles of applied behavior analysis. Thirty-seven public health nurses (PHN) from 10 rural midwestern counties received instruction about screening and management of patients with arthritis; a random half of counties also received public and physician information interventions designed to increase arthritis referrals to community physicians under specific circumstances. In clinic interviews with patients of PHN showed modest, but significant, increases in 14 of 16 target behaviors attributable to inservice education. Because measured arthritis impact was low in this older adult population, physician referral rates were not affected by either intervention. This model illustrates generalizable behavior modification guidelines that are useful adjuncts to traditional procedures for development of professional arthritis education.

Synovial inflammation in patients with early osteoarthritis of the knee

While synovitis is common in advanced osteoarthritis (OA), its prevalence and severity in patients with early or mild OA are uncertain. In our study synovial biopsies from patients with arthroscopic evidence of OA whose radiographs were normal, or showed only mild/moderate changes of OA, were examined to determine the prevalence and severity of lining cell proliferation and mononuclear cell infiltration. Synovitis was present in only 16 of 29 patients (55%) who underwent arthroscopy because of chronic knee pain and were found to have OA; no synovium from 50% of the 22 patients in this group with full thickness cartilage ulceration showed infiltration with mononuclear cells. Similarly, no evidence of synovitis was seen in biopsies from 7 of 14 additional patients with OA who did not have knee pain but who underwent arthroscopy to evaluate joint instability. An association was seen between synovial mononuclear cell infiltration and thickness of the synovial lining cell layer (p less than 0.03), but lining cell hyperplasia was found in samples from only 12% of the patients with OA in our series. The severity of OA cartilage lesions was unrelated to severity of synovitis and no topographic relationship was found between cartilage ulceration and synovitis.

Type XI collagen-degrading activity in human osteoarthritic cartilage

Homogenates of 6 samples of human osteoarthritic cartilage were shown to degrade exogenous type XI collagen. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the cleavage products generated by each homogenate were similar, and they were identical to those obtained by cleavage of the substrate with purified gelatinase. Enzyme activity, which was inhibited by EDTA, was greater in extracts of fibrillated osteoarthritic cartilage than in extracts of grossly normal cartilage from the same joint or in extracts of cartilage from joints with osteonecrosis. Activation with APMA enhanced digestion, but breakdown was apparent in extracts of fibrillated osteoarthritic cartilage even without APMA. Enzymatic degradation of type XI collagen could play a significant role in the turnover of articular cartilage in health and disease states.

Effect of naproxen sodium on the net synthesis of glycosaminoglycans and protein by normal canine articular cartilage in-vitro

The effects of the non-steroidal anti-inflammatory drug, naproxen sodium, on the metabolism of normal canine articular cartilage has been examined. At a concentration approaching that achieved in synovial fluid of patients treated with the drug (i.e. 30 micrograms mL-1) naproxen sodium had no significant effect on net synthesis of either glycosaminoglycans or protein in organ cultures of femoral condylar cartilage, nor did it increase the proportion of newly synthesized glycosaminoglycans recovered from the culture medium, suggesting that it had no direct effect on the integrity of the extracellular matrix.

Effects of tiaprofenic acid on the concentration and metabolism of proteoglycans in normal and degenerating canine articular cartilage

The effects of tiaprofenic acid (TPA), a nonsteroidal antiinflammatory drug with high potency as a cyclooxygenase inhibitor, on the metabolism of normal and degenerating articular cartilage were examined. When present in the culture medium in clinically relevant concentrations encompassing those achieved in synovial fluid of patients treated with the drug, TPA had no significant effects on net proteoglycan synthesis in organ cultures of normal, osteoarthritic or atrophic canine articular cartilage. When fed to dogs for 8 weeks in a daily dose of 100 mg, TPA had no apparent effect on cartilage water content or uronic acid concentration. The suppression of net cartilage proteoglycan synthesis caused by immobilization was not affected by administration of TPA nor did the drug affect the proportion of newly synthesized glycosaminoglycans recovered from the spent culture medium, suggesting that it did not increase proteoglycan catabolism or affect the integrity of the cartilage matrix.

Synovitis and osteoarthritic changes in canine articular cartilage after anterior cruciate ligament transection. Effect of surgical hemostasis

Anterior cruciate ligament transection (ACLT) in the dog produces changes in the articular cartilage of the unstable knee that are consistent with those of osteoarthritis (OA). To determine whether the degrees of severity of OA cartilage changes, of synovitis, and of synovial iron deposition were related to adequacy of hemostasis at the time of ACLT, a modified surgical technique was devised, whereby electrocautery was used to obtain meticulous control of bleeding when the ligament was severed and irrigation was used to remove intraarticular blood before closure of the joint. When no particular attention was given to hemostasis, 69% of the dogs showed synovitis in the OA knee 10 weeks after ACLT; when electrocautery and irrigation were used to maintain hemostasis, synovitis was present in only 24% of the OA knees 10 weeks after ACLT (P less than 0.01). Iron deposits were present in 75% of synovial samples obtained after routine ACLT, but in only 6% (P less than 0.001) when attention was given to hemostasis. Hypertrophy of articular cartilage, chondrocyte cloning, fibrillation, and changes in tangential zone chondrocytes were less prominent in the OA knee when electrocautery and irrigation were used. However, the water content, uronic acid concentration, and rate of net 35S-labeled glycosaminoglycan synthesis were similarly increased regardless of the surgical technique used, and presumably, these changes reflect the reaction of joint cartilage to mechanical instability in this model of OA.

MRI demonstration of hypertrophic articular cartilage repair in osteoarthritis

Transection of the anterior cruciate ligament in the dog produces changes in the unstable joint typical of osteoarthritis, although full-thickness cartilage ulceration is rare. Information concerning the late fate of the cartilage after transection is meager. In the present study magnetic resonance imaging (MRI) was used to evaluate cartilage abnormalities 3 years after transection. Plain radiographs of the osteoarthritic and contralateral knees were obtained serially. MRI was performed 3 years after anterior cruciate ligament transection, at which time all three animals exhibited knee instability. Radiographs of the osteoarthritic knees showed osteophytes and subchondral sclerosis with progression between 2 and 3 years. On MRI, articular cartilage margins in the knee were indistinct, and the cartilage was thicker than that in the contralateral knee (maximum difference = 2.7 mm). This increase in thickness is consistent with biochemical data from dogs killed up to 64 weeks after creation of knee instability, which showed marked increased in cartilage bulk and in proteoglycan synthesis and concentration. The findings emphasize that increased matrix synthesis after anterior cruciate ligament transection leads to functional cartilage repair sustained even in the presence of persistent alteration of joint mechanics.

Rapidly progressive Charcot arthropathy following minor joint trauma in patients with diabetic neuropathy

Neuropathic (Charcot) arthropathy is a slowly progressive, chronic, destructive form of joint degeneration seen in patients with a neurosensory deficit. Attempts to produce neuropathic joint disease experimentally with a variety of deafferentation procedures have generally been unsuccessful. However, if the knee is rendered unstable by anterior cruciate ligament transection (ACLT), breakdown of the joint occurs rapidly in dogs that have previously undergone dorsal root ganglionectomy (DRG) for deafferentation of the ipsilateral limb. In contrast, ACLT in neurologically intact dogs produces not only nonprogressive changes that are characteristic of mild osteoarthritis. This report describes 3 patients with longstanding insulin-dependent diabetes mellitus in whom neuropathic arthropathy developed within weeks after minor trauma to the foot or ankle. In these patients, diabetic neuropathy served as the functional equivalent of dorsal root ganglionectomy, and the minor trauma served as the functional equivalent of ACLT. Together, they illustrate the phenomenon of neurogenic acceleration of joint degeneration in humans.

Cartilage matrix glycoprotein is present in serum in experimental canine osteoarthritis

We have described previously a disulfide-bonded 550,000-D cartilage matrix glycoprotein (CMGP), which is found in normal hyaline cartilage, fibrocartilage, and the vitreous of the eye, and consists of subunits with apparent molecular weights of 130,000 in 4% gels (116,000 in 9% gels). In osteoarthritic cartilage from dogs subjected to transection of the anterior cruciate ligament (ACL), CMGP is cleaved to major immunoreactive fragments with apparent molecular weights of 65,000 and 75,000 after reduction with 2-mercaptoethanol. In the present study, using immunolocation analysis, a monoclonal antibody to CMGP did not react with serum from 8 of 12 dogs before ACL transection but did react with serum from seven of these animals 4 wk after surgery and with serum from 10 dogs at sacrifice, 8-14 wk after ACL transection. Serum from four dogs reacted with the monoclonal antibody before ACL transection. Serum from two dogs was negative at all time points. Immunolocation studies using a polyclonal antiserum to CMGP were performed in seven of these dogs and produced results identical with the monoclonal antibody in four dogs. In contrast, analysis of serial serum samples from three dogs with cartilage atrophy revealed no evidence of CMGP at any time point. These data suggest that CMGP may be a serum marker for osteoarthritis in this canine model.

Gait alterations in dogs after transection of the anterior cruciate ligament

We calculated mean peak vertical forces (MFz) of each limb of 9 adult mongrel dogs before and 2 weeks, 6 weeks, and 12 weeks after left anterior cruciate ligament transection (ACLT). Five additional dogs were studied before and 2 weeks and 6 weeks after sham ACLT. The gaits of 3 dogs that had undergone ACLT 2.5 years previously were also analyzed. Preoperatively, there were no differences in the MFz of the right and left hind limbs of the 9 dogs; we found that each limb exerted approximately 70% of the dog's static body weight on the force plate. Two weeks following ACLT, the MFz of the operated limbs decreased to 25% of the static body weight, while at 6 weeks and 12 weeks after surgery, the MFz generated by the operated limbs rose to about 32% and 37% of static body weight, respectively. No change was noted in the MFz of the contralateral hind limbs. In the 3 dogs that had undergone ACLT 2.5 years earlier, the MFz in the unstable stifle joint was 50% of static body weight. At both 2 weeks and 6 weeks after surgery, the MFz values for all 4 limbs of the animals subjected to sham ACLT were comparable with baseline values. These observations indicate that the osteoarthritic changes seen in the unstable limb are associated with decreased loading of that limb, without increased (compensatory) loading of the contralateral hind limb.

A pessimistic view of serologic markers for diagnosis and management of osteoarthritis. Biochemical, immunologic and clinicopathologic barriers

The diagnosis of osteoarthritis (OA) is usually based on clinical and radiologic findings and is usually made only after the patient presents with joint pain. There is today much interest in development of an immunologic "marker" of OA, to detect subclinical disease and/or monitor therapy. The approach employs measurement of serum or synovial fluid levels of articular cartilage macromolecules, such as proteoglycans or glycosaminoglycans, or fragments of these. The data, however, raise questions about interpretation and utility of such tests. What causes egress of such macromolecules from OA cartilage? Overproduction? Hypercatabolism? Leakage from an excessively permeable matrix? Does the marker reflect the rate of cartilage breakdown? Or of repair? How reliable are the quantitative immunologic methods in tests of sera from patients with OA? Data show, for example, that serum keratan sulfate levels may be influenced by the mode of presentation of the antigen, i.e., single vs multiple chains, and by the degree of sulfation, etc. To what extent might serum levels of a marker reflect release from degenerating but asymptomatic joints, rather than from painful joints? Also, since all putative marker molecules studied to date are widely distributed throughout the connective tissue of the body, they could be released from an asymptomatic degenerating intervertebral disc rather than, e.g., a painful osteoarthritic hip or knee. In the present climate of "marker mania," it should be emphasized that no marker exists today which can confidently be used for diagnosis of subclinical OA or for monitoring therapeutic response.

Radiation synovectomy stimulates glycosaminoglycan synthesis by normal articular cartilage

Radiation synovectomy has been considered a therapeutic alternative to surgical synovectomy. Whether intraarticular irradiation affects the composition or biochemistry, and therefore the biomechanical properties, of normal articular cartilage has not been established. In the present study, yttrium 90 silicate was injected into one knee of nine normal adult dogs, and three other dogs received nonradioactive yttrium silicate. When the animals were killed 4 to 13 weeks after the injection, synovium from the irradiated knees showed areas of necrosis and fibrosis. Up to 29% less hyaluronate was synthesized in vitro by the synovial intima from irradiated knees than by the intima from the contralateral knees (mean difference 18%). Morphologic abnormalities were not observed in articular cartilage from either the irradiated or control knees, nor did the water content or concentrations of uronic acid or DNA in cartilage from the irradiated knees differ from that in cartilage from the contralateral knees. However, net 35SO4-labeled glycosaminoglycan synthesis in organ cultures of cartilage from irradiated knees was increased (mean difference 21%, p = 0.03) in comparison with that in cultures of contralateral knee cartilage.

Hereditary symphalangism. Association with osteoarthritis

A pedigree is described with 5 generations affected by hereditary symphalangism of the proximal interphalangeal joints of the hands. In the proposita, osteoarthritis was present proximal and distal to the symphalangitic segment, possibly due to altered mechanical forces in these joints.

Type XI collagen is associated with the chondrocyte surface in suspension culture

Chondrocytes from bovine articular cartilage were stripped of matrix, then allowed to reconstitute their pericellular matrix in suspension culture. After incubation, the cells were centrifuged through a Percoll (TM) cushion and separated into a cell fraction, a medium fraction, and an interface fraction. The collagen in each fraction was analyzed by SDS-polyacrylamide gel electrophoresis and immunolocation with antisera against type XI and type II. Under these conditions, type XI collagen was recovered in the cell fraction, but was not detectable by immunolocation in the medium fraction or the interface fraction. In contrast, type II collagen was found in all three of these fractions. Insoluble type XI fibers subjected to the same fractionation scheme in the absence of cells were recovered in the medium and interface fractions, but not in the cell fraction. Incubation of intact cells with collagenase digested the cell-associated collagen, indicating that it was outside of the cells. The type XI collagen was removed from the cells by extraction with 4 M guanidinium chloride. These results indicate that type XI collagen is preferentially retained at the chondrocyte surface, and are consistent with our proposal that it is involved in organization of the pericellular matrix.

Lack of association between serum keratan sulfate concentrations and cartilage changes of osteoarthritis after transection of the anterior cruciate ligament in the dog

To determine whether the serum keratan sulfate (KS) concentration reflected the status of degenerating articular cartilage in a commonly used model of osteoarthritis (OA), serum KS levels were measured in 9 dogs prior to transection of the anterior cruciate ligament, 4 weeks later, and when the dogs were killed 8-14 weeks after surgery, at which time mild OA was present. In all cases, the serum KS levels were within the normal range. Values were not related to the cartilage uronic acid concentration, the rate of net 35SO4 glycosaminoglycan synthesis, or the histopathologic changes of OA. Although the serum KS concentration was not helpful as an indicator of the current status of the articular cartilage abnormality in the OA knee, serial samples from 6 dogs showed an increase of at least 10% over the baseline KS level at both timepoints following surgery (P = 0.031 and 0.027). This presumably reflects changes in proteoglycan metabolism in the unstable knee, although the possibility of a systemic change in proteoglycan metabolism following cruciate ligament transection cannot be excluded.

Suppression of glycosaminoglycan synthesis by articular cartilage, but not of hyaluronic acid synthesis by synovium, after exposure to radiation

We recently found that injection of 2 mCi of yttrium 90 (90Y; approximately 23,000 rads) into normal canine knees stimulated glycosaminoglycan (GAG) synthesis by femoral condylar cartilage. The present investigation was conducted to determine whether radiation affects cartilage metabolism directly. Rates of GAG synthesis and degradation in normal canine articular cartilage were studied following irradiation. Cultured synovium from the same knees was treated similarly, to determine the effects of irradiation on hyaluronic acid synthesis. Twenty-four hours after exposure to 1,000 rads, 10,000 rads, or 50,000 rads, 35S-GAG synthesis by the cartilage was 93%, 69%, and 37%, respectively, of that in control, nonirradiated cartilage. The effect was not rapidly reversible: 120 hours after exposure to 50,000 rads, GAG synthesis remained at only 28% of the control level. Autoradiography showed marked suppression of 35S uptake by chondrocytes after irradiation. Cartilage GAG degradation was also increased following irradiation: 4 hours and 8 hours after exposure to 50,000 rads, the cartilage GAG concentration was only 66% and 54%, respectively, of that at time 0, while corresponding values for control, nonirradiated cartilage were 90% and 87%. In contrast to its effects on cartilage GAG metabolism, radiation at these levels had no effect on synovial hyaluronic acid synthesis.

Effects of salicylate on chondrocytes from osteoarthritic and contralateral knees of dogs with unilateral anterior cruciate ligament transection

Salicylates suppress net glycosaminoglycan synthesis in articular cartilage. The inhibitory effect is greater in osteoarthritic (OA) cartilage than in normal cartilage. Whether the isolated OA chondrocyte is inherently more susceptible to the effects of salicylate on glycosaminoglycan metabolism has not been determined. The results of this study show that, after isolation from the extracellular matrix, normal and OA chondrocytes in suspension culture are similarly susceptible to the metabolic effects of salicylate. However, chondrocytes from the contralateral knees of dogs with unilateral OA were notably resistant to the effects of salicylate.

Infectious complications of cyclophosphamide treatment for vasculitis

Fifteen patients with Wegener's granulomatosis, polyarteritis nodosa, or isolated angiitis of the central nervous system were treated with cyclophosphamide according to a widely used regimen. Seventeen clinical episodes of infection were observed over 201 patient-months of cyclophosphamide therapy, and 2 patients died of pneumonia. Notably, neither the incidence of leukopenia nor the dosage or duration of cyclophosphamide or corticosteroid therapy correlated well with infection, which occurred most frequently in men over 60 years of age. Patients with Wegener's granulomatosis appeared to be at greater risk of infection than those with the other forms of vasculitis. These results suggest that this treatment regimen may not be as safe as was previously thought.