Pneumococcal Pyomyositis: A Patient with Diagnostic Problems and Complications

Pyomyositis is an uncommon condition that may present a difficult problem in diagnosis. We report the development of Streptococcus pneumoniae pyomyositis involving the iliacus, iliopsoas, and gluteus muscles in a patient with elevated serum levels of antinuclear and antiphospholipid antibodies but without clinical evidence of connective tissue disease. Magnetic resonance imaging demonstrated rapid evolution of the infection, with progression from muscle edema to abscess formation over a period of 10 days. The diagnosis was initially missed, and osteomyelitis and sacroiliitis developed. Pyomyositis should be suspected in patients with the acute onset of severe, localized muscle pain and fever. As in this case, failure to promptly diagnose and treat this infection can result in significant morbidity.

Osteoarthritis: new insights. Part 1: the disease and its risk factors

Osteoarthritis is the most common form of arthritis, affecting millions of people in the United States. It is a complex disease whose etiology bridges biomechanics and biochemistry. Evidence is growing for the role of systemic factors (such as genetics, dietary intake, estrogen use, and bone density) and of local biomechanical factors (such as muscle weakness, obesity, and joint laxity). These risk factors are particularly important in weight-bearing joints, and modifying them may present opportunities for prevention of osteoarthritis-related pain and disability. Major advances in management to reduce pain and disability are yielding a panoply of available treatments ranging from nutriceuticals to chondrocyte transplantation, new oral anti-inflammatory medications, and health education. This article is part 1 of a two-part summary of a National Institutes of Health conference. The conference brought together experts on osteoarthritis from diverse backgrounds and provided a multidisciplinary and comprehensive summary of recent advances in the prevention of osteoarthritis onset, progression, and disability. Part 1 focuses on a new understanding of what osteoarthritis is and on risk factors that predispose to disease occurrence. It concludes with a discussion of the impact of osteoarthritis on disability.

A comparison of lower extremity muscle strength, obesity, and depression scores in elderly subjects with knee pain with and without radiographic evidence of knee osteoarthritis

OBJECTIVE

To determine, in subjects with knee pain but no radiographic changes of tibiofemoral or patellofemoral compartment osteoarthritis (OA), whether mean body weight, quadriceps and hamstring strength, lower extremity muscle mass, depression scores, and perceptions of their general health status differed from those of subjects with symptomatic knee OA.

METHODS

Subjects were 25 women and 10 men with knee pain and radiographic evidence of OA at the baseline examination, and 21 women and 16 men who had knee pain at the baseline examination but no radiographic evidence of knee OA at either baseline examination or followup evaluation performed, on average, 31 months later. These individuals were a subset of a cohort of 462 independently living elderly individuals recruited by telephone interview after random selection through random digit dialing of households in central Indiana. Data from an additional 134 subjects who had neither knee pain nor radiographic changes of OA at either the baseline or followup examination were analyzed for comparison. Lower extremity muscle strength was measured by isokinetic dynamometry, lean tissue (i.e., muscle) mass in the lower extremities by dual x-ray absorptiometry, depression by Center for Epidemiology Depression (CES-D) scale. knee pain by Western Ontario McMaster University OA instrument, and perceived general health status by the Medical Outcome Survey Short Form-36.

RESULTS

In contrast to those with symptomatic knee OA, those who had knee pain but no radiographic evidence of OA were less obese, had hamstring as well as quadriceps weakness, and had CES-D scores high enough to qualify for a diagnosis of clinical depression.

CONCLUSION

Among subjects with knee pain but no OA--and among women in this subset, in particular--knee pain may be a manifestation of depression. rather than of joint disease.

The role of analgesics in the management of osteoarthritis pain

Osteoarthritis (OA), previously called degenerative joint disease, is a common condition. Figures from the United States indicate that as many as 80% of the population has radiographic evidence of this disease by the age of 65 years, and difficulty with ambulation, mostly attributable to OA, accounts for as many as 30% of all visits to a doctor. There is no known cure for OA and hence treatments are used to reduce pain and other symptoms, maintain and/or improve joint mobility, and limit functional disability, with the overall management goal of improving the patients' quality of life. To this point, one of the key objectives of treatment is to manage knee pain. In the past, treatment was most often initiated with the prescription of nonsteroidal anti-inflammatory drugs (NSAIDs). However, evidence that (1) NSAIDs offer no additional symptomatic benefit over simple analgesics, such as paracetamol (acetaminophen), for many patients with OA, (2) NSAID-related adverse gastrointestinal (GI) effects are a significant cause or morbidity and mortality, and (3) NSAIDs could have a possible deleterious effect on articular cartilage metabolism, has led to a change in management strategy. Contemporary thinking is that nonpharmacologic measures should be tried first, with pharmacologic intervention used as an adjunct. Nonpharmacologic therapy includes such things as patient education, weight loss, physical therapy, occupational therapy, and exercise. Paracetamol, in doses of as high as 4000 mg/day, is the first-line drug of choice for the management of the pain of OA. If the patient does not respond to paracetamol, NSAIDs may be an appropriate alternative, provided they are not medically contraindicated. Because of their GI toxicity, it is suggested that NSAIDs be used in the lowest possible dose for the shortest possible time. In OA, the intensity of pain varies both during the day and night, enabling the use of NSAIDs with a short half-life on an as-needed basis. Strategies to reduce the risk of NSAID-related GI complications include prophylaxis with misoprostol. Current developments in the field of OA management are also discussed, including the emergence of drugs that specifically inhibit cyclooxygenase 2 (COX-2) and disease-modifying treatments.

Synovial fluid glycosaminoglycan concentration does not correlate with severity of chondropathy or predict progression of osteoarthritis in a canine cruciate deficiency model

OBJECTIVE

Considerable interest exists today in biochemical or immunochemical tests for monitoring the progression of osteoarthritis (OA). It has been suggested that measurements made on synovial fluid (SF) will more accurately reflect the magnitude of cartilage destruction in an index joint than those performed on serum. However, we have shown that the synovitis that occurs in OA affects the rate of protein clearance from the joint. We tested the hypothesis that if adjusted for clearance rate, the SF concentration of cartilage proteoglycans (PG) estimates severity of chondropathy and predicts progression of cartilage damage more accurately than if clearance is not taken into account.

METHODS

Clearance of radioiodinated serum albumin (RISA), a surrogate for the clearance of PG, was measured in 19 adult dogs at baseline and again 16 weeks and 32 weeks after anterior cruciate ligament transection (ACLT). Severity of chondropathy was determined arthroscopically after 16 weeks of instability and at postmortem 32 weeks after ACLT.

RESULTS

Adjustment for the RISA clearance rate showed that the SF PG concentration markedly underestimated the quantity of PG released from the OA cartilage. Regardless of whether the concentration was adjusted for clearance, no correlation existed between the SF PG level and the severity of chondropathy. Further, the SF concentration of PG 16 weeks after ACLT failed to predict severity of cartilage damage at postmortem.

CONCLUSION

SF concentration of a cartilage derived molecule is unlikely to predict the course of cartilage damage in an OA joint over time or in response to treatment with a potential disease modifying OA drug.

Effects of a bisphosphonate on bone histomorphometry and dynamics in the canine cruciate deficiency model of osteoarthritis

OBJECTIVE

To examine the effect of the bisphosphonate NE- 10035 on bone histomorphometry and bone dynamics in dogs after transection of the anterior cruciate ligament (ACL), and to determine, in a placebo controlled trial, whether treatment modified the severity of pathologic changes of osteoarthritis (OA) in the unstable joint.

METHODS

Ten adult male mongrel dogs underwent ipsilateral ACL transection. Five dogs then received daily subcutaneous injections of NE-10035 on 5 days per week for 12 weeks beginning the day after surgery. The other 5 dogs served as concurrent OA controls and received subcutaneous injections of saline on the same schedule. At sacrifice, 12 weeks after ACL transection, the articular cartilage and synovium of both knees of each dog were evaluated grossly and histologically and the water content and uronic acid concentration of the articular cartilage was determined. Fifteen days before sacrifice, each dog was injected with the fluorochrome label calcein. The injection regimen was repeated 10 days after the initial date. At sacrifice, static and dynamic variables of bone formation were assessed and bone resorption was quantified.

RESULTS

In the OA knee of the control group, bone formation and resorption were markedly increased. NE-10035 markedly reduced both formation and resorption of cancellous subchondral bone, but had no effect on osteophyte formation or pathologic changes of OA in the articular cartilage, which were mild in both treatment groups. Water content of the OA cartilage was increased by about 8% in both treatment groups. However, among the controls, the mean uronic acid concentration of the OA cartilage was increased by about 30% in comparison with values for the contralateral knee, while in the NE-10035 treatment group the mean uronic acid concentration of OA knee cartilage was about 15% lower in the active treatment group than in cartilage from the contralateral knee (p = 0.003 for the difference in OA knee uronic acid concentration between the 2 treatment groups, relative to that in the contralateral knee).

CONCLUSION

The antiresorptive agent employed in this study effectively reduced turnover of subchondral bone in the OA joint, consistent with the coupling of bone formation to bone resorption at that site. Nonetheless, over the 12 week period of the study it had no effect on osteophyte formation, in which bone formation occurs via enchondral ossification and is not linked to bone resorption, and, despite the clear inhibition of bone turnover in the OA knee of the active treatment group, did not affect the severity of cartilage changes of OA. It should be noted, however, that although treatment with this antiresorptive agent did not affect the level of chondropathy, the cartilage changes in both treatment groups were relatively mild and the sample size relatively small. Additional studies with a larger number of animals and a longer period of observation (to increase the severity of pathology) are warranted to determine whether the inhibition of bone turnover and the decrease in proteoglycan concentration that resulted from therapy will affect articular cartilage degeneration in the OA joint.

Serial force plate analyses of dogs with unilateral knee instability, with or without interruption of the sensory input from the ipsilateral limb

OBJECTIVE AND DESIGN

We characterized the mean peak vertical forces (MFz) in five groups of dogs which underwent transection of the left anterior cruciate ligament (ACLT) or sham ACLT and ipsilateral dorsal root ganglionectomy or sham-ganglionectomy, and the relationship of these forces to the severity of osteoarthritis (previously reported) 72 weeks after arthrotomy. Group I (N=7) underwent ACLT; Group II (N=8) underwent ACLT followed 52 weeks later by ganglionectomy; Group III (N=7) underwent ganglionectomy followed 2 weeks later by ACLT; Group IV (N=7) underwent sham-ganglionectomy followed 2 weeks later by ACLT; Group V (N=8) underwent ganglionectomy followed 2 weeks later by sham-ACLT. The dogs were evaluated 2, 6, 12, 24, 52 and 72 weeks after arthrotomy.

RESULTS

From 6 weeks after arthrotomy until death, the left hindlimb MFz in Group V was significantly greater (P< 0.05) than that in the other four groups. The MFz of all groups which underwent ACLT decreased after arthrotomy. While the MFz of Group III (very severe OA) was about 10-20% greater than that of Groups I, II and IV (mild OA) 6 and 12 weeks after ACLT, and generally about 5-10% greater subsequently, this difference was not statistically significant. The MFz of Group II returned to pre-ganglionectomy levels, rather than to baseline levels, following ganglionectomy.

CONCLUSIONS

(1) since the ipsilateral limb of dogs with ganglionectomy+sham ACLT bore normal amounts of weight throughout most of the postsurgical period, and its knee did not develop OA, one cannot argue that the knee was protected from OA because the limb was not used; (2) the fact that the MFz of dogs which underwent ACLT+ganglionectomy returned to pre-ganglionectomy levels, rather than baseline, is consistent with the hypothesis that the unstable joint was protected from accelerated breakdown by a central nervous system that was reprogrammed by sensation from the unstable limb; (3) the slightly-but consistently-greater MFz of dogs which underwent ganglionectomy+ ACLT may contribute to the acceleration of OA in this model.

Quadriceps strength in women with radiographically progressive osteoarthritis of the knee and those with stable radiographic changes

OBJECTIVE

To explore the relationship between lower extremity weakness and the progression of established radiographic changes of knee osteoarthritis (OA).

METHODS

The study cohort of 342 elderly subjects was recruited from central Indiana by random digit dialing. We analyzed 79 subjects who had definite radiographic changes of unilateral or bilateral knee OA at baseline and for whom baseline data for lower extremity muscle strength and lean tissue mass and baseline and followup assessments of knee pain were available. Radiographs were graded for severity of OA at baseline and again about 2.5 years later (mean 31.5 months). Knee pain was evaluated at the same examination. Strength of the knee flexors and extensors was assessed bilaterally at baseline by isokinetic dynamometry and lower extremity muscle mass by dual energy x-ray absorptiometry.

RESULTS

Mean peak knee extensor strength of women with progressive OA, before and after adjustment for lower extremity muscle mass, was about 9% lower than that in those with stable radiographic changes, but this difference was not statistically significant. No difference was apparent between the 2 groups with respect to knee flexor (hamstring) strength. The decrease in quadriceps strength among women with progressive OA, relative to those with stable OA, did not appear to be attributable to knee pain, and knee extensor strength at baseline bore no apparent relationship to the development or progression of knee pain among those with OA.

CONCLUSION

We have shown previously that quadriceps weakness may be of etiologic importance in development of knee OA. The absence of a significant difference in quadriceps strength between subjects with radiographically stable OA and those whose joint damage progressed suggests that factors other than quadriceps weakness are more important determinants of OA progression.

Reduced utilization and cost of primary care clinic visits resulting from self-care education for patients with osteoarthritis of the knee

OBJECTIVE

To determine the extent to which the cost of an effective self-care intervention for primary care patients with knee osteoarthritis (OA) was offset by savings resulting from reduced utilization of ambulatory medical services.

METHODS

In an attention-controlled clinical trial, 211 patients with knee OA from the general medicine clinic of a municipal hospital were assigned arbitrarily to conditions of self-care education (group E) or attention control (group AC). Group E (n = 105) received individualized instruction and followup emphasizing nonpharmacologic management of joint pain. Group AC (n = 106) received a standard public education presentation and attention-controlling followup. A comprehensive clinical database provided data concerning utilization and cost of health services during the following year.

RESULTS

Only 25 subjects (12%) were lost to followup. The 94 subjects remaining in group E made 528 primary care visits during the year following intervention, compared with 616 visits by the 92 patients remaining in group AC (median visits 5 versus 6, respectively; P < 0.05). Fewer visits translated directly into reduced clinic costs in group E, relative to controls (median costs [1996 dollars] $229 versus $305, respectively; P < 0.05). However, self-care education had no significant effects on utilization and costs of outpatient pharmacy, laboratory, or radiology services over the ensuing year. The cost per patient to deliver the self-care intervention was estimated to be $58.70.

CONCLUSION

Eighty percent of the cost of delivering effective self-care education to the knee OA patients in this study was offset within 1 year by the reduced frequency and costs of primary care visits. For >50% of patients receiving the intervention, the savings associated with fewer primary care visits exceeded the cost of self-care education.

Field test of the reproducibility of automated measurements of medial tibiofemoral joint space width derived from standardized knee radiographs

OBJECTIVE

To estimate the reproducibility of computerized measurements of minimum joint space width (JSW) in the medial tibiofemoral compartment in knee radiographs (semiflexed AP view) obtained from clinical radiology units.

METHODS

Technologists from 5 clinical radiology units were trained in the performance of the fluoroscopically assisted semiflexed AP knee examination. Each of 44 subjects (34 with knee osteoarthritis, OA, 10 with bilaterally normal knees) were examined within 7 days in 2 of the 5 units. The examination in each unit was repeated 1 week later. Minimum JSW was measured on digitized radiographic images with computer software that corrected for radiographic magnification.

RESULTS

Despite ongoing quality control by technologists, 11% of radiographs were flawed with respect to the protocol standard for knee rotation and 36% with respect to the standard for knee flexion. The standard error of measurement (SEm) of JSW in 174 knees that were examined twice in the same unit was 0.32 mm (SEm = 0.25 mm for the subset of 76 paired radiographs with uniformly high quality). The overall between-unit SEm was 0.45 mm. Within-unit, but not between-unit, precision was related to the technical quality of the radiographs. Precision was unrelated to subject age, sex, race, weight, and radiographic severity of knee OA.

CONCLUSION

The within-unit precision of JSW measurements from all pairs of semiflexed views (irrespective of technical quality) represented a notable improvement over that observed in radiographs with flawed knee rotation or flexion (as would be the case in conventional extended knee views). In future applications of this technique, assurance of technical quality by an independent observer should result in a level of measurement precision that will permit the design of clinical trials of disease modifying OA drugs with fewer subjects and/or shorter duration of treatment than is possible with conventional knee radiography.

Specificity of inhibition of matrix metalloproteinase activity by doxycycline: relationship to structure of the enzyme

OBJECTIVE

To investigate the inhibition of matrix metalloproteinase 1 (MMP-1), MMP-8, and MMP-13 by doxycycline, and to determine whether the variable hemopexin-like domain of each MMP was responsible for the differences in susceptibility to doxycycline inhibition among these collagenases.

METHODS

Recombinant human MMP-1 (collagenase 1), MMP-8 (collagenase 2), and MMP-13 (collagenase 3), truncated forms of MMP-8 and MMP-13 lacking the hemopexin-like domain, and a mutant form of truncated MMP-13 were used in these studies. The activity of the full-length MMP in the presence of doxycycline was tested against type II collagen, a natural substrate for the enzymes. A small peptolide substrate was used to determine which structural features of the MMPs were related to sensitivity to doxycycline inhibition.

RESULTS

The activity of MMP-13 and MMP-8 against type II collagen was inhibited by 50-60% by 30 microM doxycycline, while that of MMP-1 was inhibited only 18% by 50 microM doxycycline. In contrast, in experiments with the peptolide substrate, neither full-length nor truncated MMP-13 was inhibited until the concentration of the drug exceeded 90 microM. MMP-8 and truncated MMP-8 were sensitive to inhibition by 30 microM doxycycline, while MMP-1 was slightly inhibited (14%) by 90 microM doxycycline. For MMP-8, inhibition was reversible upon dilution and was independent of the order in which the reagents were added. Kinetic analysis of the inhibition constant (K(i)) of MMP-8 (K(i) = 36 microM) and truncated MMP-8 (K(i) = 77 microM) indicated that inhibition was noncompetitive.

CONCLUSION

Significant inhibition of MMP-13 and MMP-8 activity against collagen occurred in vitro at concentrations that were near the concentrations achieved in serum after oral dosing. Studies with truncated enzymes and 2 substrates suggest that doxycycline disrupts the conformation of the hemopexin-like domain of MMP-13 and the catalytic domain of MMP-8.

Plain radiography as an outcome measure in clinical trials involving patients with knee osteoarthritis

The identification of pharmacologic agents that inhibit matrix metalloproteinase activity and may serve as effective disease-modifying osteoarthritis drugs (DMOADs) in humans has led to interest in the ability of plain radiographic methods to detect early cartilage damage and assess progressive cartilage changes of knee osteoarthritis (OA). Conventional knee radiography lacks sufficient standardization of key elements of the radioanatomic positioning of the knee to avoid significant, probably insurmountable, error variation in the measurement of tibiofemoral joint space width (JSW), the surrogate for the thickness of articular cartilage in radiographic images. Recently, several protocols for the use of fluoroscopy to standardize the radioanatomic position of the knee in a plain radiograph have been shown to afford notably more precise measurement of medial tibiofemoral JSW than can be derived from unstandardized, conventional techniques. A field test of one of these protocols suggests that DMOAD trials with respect to sample size or duration of treatment necessary to detect true OA progression and demonstrate a drug effect may be more feasible.

Diacerhein treatment reduces the severity of osteoarthritis in the canine cruciate-deficiency model of osteoarthritis

OBJECTIVE

To determine if diacerhein protects against the early stages of joint damage in a canine model of osteoarthritis (OA).

METHODS

OA was induced in 20 adult mongrel dogs by transection of the anterior cruciate ligament of the left knee. Beginning the day after surgery, dogs in the active treatment group were dosed twice a day with capsules of diacerhein, providing a total daily dose of 40 mg/kg, for 32 weeks. Dogs in the control group received placebo capsules on the same schedule. Pathology in the unstable knee was assessed arthroscopically 16 weeks after surgery and by direct observation when the dogs were killed 32 weeks after surgery. The severity of gross joint pathology was recorded, and samples of the medial femoral condyle cartilage and the synovial tissue adjacent to the central portion of the medial meniscus were collected for histologic evaluation. Water content and uronic acid concentration of the articular cartilage from the femoral condyle were determined, and collagenolytic activity in extracts of cartilage pooled from the medial and lateral tibial plateaus was assayed against 14C-labeled collagen fibers.

RESULTS

Diacerhein treatment slowed the progression of OA, as measured by grading of gross changes in the unstable knee at arthroscopy 16 weeks after cruciate ligament transection (P = 0.04) and at the time the animals were killed, 32 weeks after surgery (P = 0.05). However, 32 weeks after ACL transection, the mean proteoglycan concentration and water content of the OA cartilage and the level of collagenolytic activity in extracts of the cartilage were not significantly different in the diacerhein treatment group than in the placebo treatment group.

CONCLUSION

Diacerhein treatment significantly reduced the severity of morphologic changes of OA compared with placebo. These findings support the view that diacerhein may be a disease-modifying drug for OA.

Reduced quadriceps strength relative to body weight: a risk factor for knee osteoarthritis in women?

OBJECTIVE

To determine whether baseline lower extremity muscle weakness is a risk factor for incident radiographic osteoarthritis (OA) of the knee.

METHODS

This prospective study involved 342 elderly community-dwelling subjects (178 women, 164 men) from central Indiana, for whom baseline and followup (mean interval 31.3 months) knee radiographs were available. Lower extremity muscle strength was measured by isokinetic dynamometry and lean tissue (i.e., muscle) mass in the lower extremities by dual x-ray absorptiometry.

RESULTS

Knee OA was associated with an increase in body weight in women (P = 0.0014), but not in men. In both sexes, lower extremity muscle mass exhibited a strong positive correlation with body weight. In women, after adjustment for body weight, knee extensor strength was 18% lower at baseline among subjects who developed incident knee OA than among the controls (P = 0.053), whereas after adjustment for lower extremity muscle mass, knee extensor strength was 15% lower than in the controls (P not significant). In men, in contrast, adjusted knee extensor strength at baseline was comparable to that in the controls. Among the 13 women who developed incident OA, there was a strong, highly significant negative correlation between body weight and extensor strength (r = -0.740, P = 0.003), that is, the more obese the subject, the greater the reduction of quadriceps strength. In contrast, among the 14 men who developed incident OA, a modest positive correlation existed between weight and quadriceps strength (r = 0.455, P = 0.058). No correlation between knee flexor (hamstring) strength and knee OA was seen in either sex.

CONCLUSION

Reduced quadriceps strength relative to body weight may be a risk factor for knee OA in women.

The importance of nonpharmacologic approaches in management of osteoarthritis

Treatment of the patient with osteoarthritis should be comprehensive, with nonpharmacologic approaches considered as primary therapy, and analgesics and nonsteroidal anti-inflammatory drugs (NSAIDs) assigned to an adjunctive role. These nonmedicinal approaches can include joint protection strategies; the use of thermal modalities (heat and cold) and transcutaneous electrical nerve stimulation (TENS); the development of exercise programs (that focus not only on the localized impairment, but on the functional limitations and disability secondary to inactivity); weight loss programs; the use of patellar tapping, wedged insoles, tidal irrigation (of the knee); and the introduction of coping skills and social support.

Effect of intraarticular hyaluronan injection in experimental canine osteoarthritis

OBJECTIVE

To determine if intraarticular injections of hyaluronan (HA) protect against the early stages of joint damage in a canine model of osteoarthritis (OA).

METHODS

OA was induced in adult mongrel dogs by transection of the anterior cruciate ligament of the left knee. One group of dogs (n=7) was treated with 5 weekly injections of HA (MW 1,500,000) into the operated knee beginning 1 day after ligament transection. The control group (n=6) was injected with saline on the same schedule. Twelve weeks after surgery, all dogs were killed, the severity of pathologic changes of OA was graded, and composition of the cartilage and extent of aggregation of proteoglycans (PGs) synthesized in vitro by cartilage slices were determined.

RESULTS

All dogs showed gross morphologic changes typical of OA in the unstable knee. The severity of joint pathology in HA-treated dogs was comparable with that in the saline-injected controls. In OA cartilage from the saline-treated group, the mean uronic acid concentration was 30-60% greater than that in the contralateral knee. In sharp contrast, the uronic acid concentration in OA cartilage from the HA-treated dogs was 10-30% lower than that in cartilage from the contralateral knee (P=0.02 and P=0.03, respectively, for samples from the medial and lateral femoral condyle). The extent of aggregation of PG synthesized in vitro by cartilage from HA-injected animals was similar to that synthesized by cartilage from the saline-injected dogs.

CONCLUSION

In this canine model of OA, the series of intraarticular injections of HA did not alter development of osteophytosis or fibrillation. However, the PG concentration of cartilage in the OA knee was significantly reduced by this treatment, suggesting that HA therapy might adversely affect the biomechanical properties of the cartilage.

Oral administration of doxycycline reduces collagenase and gelatinase activities in extracts of human osteoarthritic cartilage

OBJECTIVE

To determine whether oral administration of doxycycline in clinically relevant doses will suppress activities of collagenase and gelatinase in extracts of human osteoarthritic (OA) cartilage.

METHODS

Femoral heads were obtained from 21 patients undergoing arthroplasty for endstage hip OA. Activities of collagenase and gelatinase were measured in extracts of the OA cartilage from patients who received doxycycline, 100 mg bid or qam for 5 days before surgery (n = 5 and n = 6, respectively), 200 mg as a single dose 3 days before surgery (n = 4); or no doxycycline (n = 6).

RESULTS

Five days of doxycycline treatment, in a dose of either 100 mg bid or 100 mg qam, inhibited gelatinase activity in the cartilage extracts (p = 0.003, 0.008, respectively). The bid dose also inhibited collagenase activity (p = 0.002), but inhibition of collagenase with 100 mg qam did not quite reach statistical significance (p = 0.055), in comparison with the values for the untreated OA controls. The single 200 mg dose, given 3 days before procurement of the cartilage, was ineffective in inhibiting metalloproteinase activity.

CONCLUSION

Oral administration of doxycycline significantly inhibited collagenase and gelatinase activity in human OA cartilage. The effective dose is likely to be well tolerated during chronic administration, e.g., in a clinical trial to assess the potential of the drug to modify cartilage breakdown in OA.

Effects of diacerhein in an accelerated canine model of osteoarthritis

OBJECT

To determine whether diacerhein has a disease-modifying effect in an accelerated canine model of osteoarthritis.

DESIGN

Fourteen adult mongrel dogs underwent unilateral L4-S1 dorsal root ganglionectomy (DRG), followed 3 weeks later by ipsilateral anterior cruciate ligament transection. Seven dogs received diacerhein (15-20 mg/kg) daily throughout the interval between DRG and sacrifice, eight weeks after ligament transection. The other seven dogs served as OA controls.

RESULTS

The mean volume of synovial fluid obtained from the OA knee of the diacerhein-treated dogs was approximately 40% less than that from the OA knee of the controls. In addition, diacerhein appeared to reduce the severity of fibrillation (femoral condyle) and full-thickness ulceration (trochlear ridge) of the articular cartilage and the level of collagenase activity in extracts of the OA cartilage, and to increase net PG synthesis in the OA cartilage, although none of the above changes were statistically significant.

CONCLUSION

The differences between the diacerhein group and untreated OA controls, even though not statistically significant, suggest that diacerhein was active in this rapidly progressive model of OA. Because changes associated with initiation of OA may be different than those associated with progression, whether diacerhein has a disease-modifying effect should be examined in a less rapidly progressive model.

Comparison of general internists, family physicians, and rheumatologists managing patients with symptoms of osteoarthritis of the knee

OBJECTIVE

To evaluate the nature, risks, and benefits of osteoarthritis (OA) management by primary care physicians and rheumatologists.

METHODS

Subjects were 419 patients followed for symptoms of knee OA by either a specialist in family medicine (FM) or general internal medicine (GIM) or by a rheumatologist (RH). Management practices were characterized by in-home documentation by a visiting nurse of drugs taken to relieve OA pain or to prevent gastrointestinal side effects of nonsteroidal anti-inflammatory drugs (NSAIDs) and by patient report (self-administered survey) of nonpharmacologic treatments. Changes in outcomes (knee pain and physical function) over 6 months were measured with the Western Ontario and McMaster Universities Osteoarthritis Index.

RESULTS

Patients of RHs were 2-3 years older (P = 0.035) and tended to exhibit greater radiographic severity of OA (P = 0.064) and poorer physical function (P = 0.076) at baseline than the other 2 groups. In all 3 groups, knee pain and physical function improved slightly over 6 months; however, between-group differences were not significant. Compared to drug management of knee pain by FMs or RHs, that by the GIMs was distinguished by greater utilization of acetaminophen and nonacetylated salicylates (P = 0.008), lower prescribed doses of NSAIDs (P = 0.007), and, therefore, lower risk of iatrogenic gastroenteropathy (P < 0.001). In contrast, patients of RHs were more likely than those of FMs and GIMs to report that they had been instructed in use of isometric quadriceps and range-of-motion exercises (P < or = 0.001), application of heat (P = 0.051) and cold (P < 0.001) packs, and in the principles of joint protection (P = 0.016). Neither physician specialty nor specific management practices accounted for variations in patient outcomes.

CONCLUSION

This observational study identified specialty-related variability in key aspects of the management of knee OA in the community (i.e., frequency and dosing of NSAIDs, use of nonpharmacologic modalities) that bear strong implications for long-term safety and cost. However, changes in knee pain and function over 6 months were unrelated to variations in management practices.

Periosteal new bone formation in a canine neuropathic model of osteoarthritis

OBJECTIVE

To characterize, for the first time, periosteal new bone formation in a well-established canine model of accelerated osteoarthritis (OA) with features of neuropathic arthropathy.

METHODS

Seven dogs underwent left L4-S1 dorsal root ganglionectomy (DRG), followed 3 weeks later by transection of the anterior cruciate ligament of the ipsilateral knee (ACLT). Eight weeks thereafter, a postmortem examination was performed to assess the severity of cartilage changes of OA and the formation of new bone on the distal femur and proximal tibia in the cruciate-deficient limb.

RESULTS

As described previously, extensive full-thickness ulceration of the articular cartilage was present in the unstable knee of every dog. The femoral shaft immediately proximal to the condyles in the unstable limb was consistently wider (mean +/- SD diameter 22.4 +/- 2.2 mm) than that in the contralateral limb (19.9 +/- 1.3 mm; P = 0.01). Xeroradiography and histologic examination of the distal femur revealed extensive formation of woven bone on the periosteal surfaces of the medial, lateral, and anterior aspects of the femoral shaft in the OA limb of every dog. These bony changes were not seen in radiographs of dogs that underwent DRG with the cruciate ligament left intact (n = 8) or of neurologically intact dogs that underwent ACLT (n = 7) and were examined 24 weeks after surgery.

CONCLUSION

Formation of new periosteal bone on the distal femur and tibia is a feature of this model of accelerated OA that is not seen in the conventional ACLT model of OA in the neurologically intact dog. This observation suggests that interruption of sensory input from the limb may affect the regulation of osteogenesis in the mechanically unstable joint.