WORKUP	Section 5 of 11
Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Pictures Bibliography

Lab Studies:

• No laboratory studies can assist in diagnosis of osteoarthritis (OA) per se. Previous work has not led to a clinically useful diagnostic test.

• Researchers have looked at monoclonal antibodies, synovial fluid markers, and urinary pyridinium cross-links (ie, breakdown products of cartilage). Erythrocyte sedimentation rate (ESR) is not usually elevated, but it may be slightly elevated in cases of erosive inflammatory arthritis.

Imaging Studies:

• Studies on diagnostic use of MRI in OA of the knee are currently being conducted. A study was performed to try and correlate the clinical features and MRI findings of osteoarthritis. A large joint effusion was associated with pain and stiffness. The presence of an osteophyte in the patellofemoral compartment was associated with pain. All other imaging findings, including focal or diffuse cartilaginous abnormalities, subchondral cysts, bone marrow edema, subluxation of the meniscus, meniscal tears, and Baker cysts, were not associated with symptoms (Kornaat, 2004; Kornaat, 2006).

• Bone scans may be helpful in early diagnosis of OA of the hand. Bone scans also can help to differentiate joint pain due to OA from pain associated with other disease processes. For example, bone scans typically yield a symmetric pattern of very mild increased uptake in a symmetrical manner in OA. In contrast, bone scans are often negative in early stages of multiple myeloma, another cause of bone pain in older adults that can be confused with OA. Bone scans also can help to differentiate OA from osteomyelitis and bone metastases. Single photon emission tomography scanning helps to differentiate back pain due to degenerative disk disease from back pain due to spondylolysis.

• Plain radiographs are often negative early in the disease.

• The Kellgren & Lawrence Grading System, which is the most universally accepted method of classifying radiographic osteoarthritis, uses the following 4 radiographic features:

• Joint space narrowing

• Osteophytes

• Subchondral sclerosis

• Subchondral cysts

Other Tests:

• Perform diagnostic joint aspiration for synovial fluid analysis to help rule out other conditions.

	TREATMENT	Section 6 of 11
Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Pictures Bibliography

Rehabilitation Program:

• Physical Therapy: Lifestyle modification, particularly exercise and weight reduction, is a core component of the management of osteoarthritis (OA) (Roddy, 2006). A program of physical therapy should emphasize the importance of strengthening all muscles that cross the given joint affected by OA.

  Most research focuses on quadriceps strengthening in knee OA. Also important are stretching exercises, which increase range of motion. The importance of aerobic conditioning, particularly low-impact exercises if OA affects weight-bearing joints, should be stressed. Swimming, especially aerobic aquatic programs through the Arthritis Foundation, can be helpful. Certain studies also indicate that a home exercise program for patients with OA of the knee provides an important benefit.

  A review was written on patient adherence to exercise (Marks, 2005). The article concluded that interventions to enhance self-efficacy, social support, and skills in long-term monitoring of progress are necessary to foster exercise adherence among people with OA.

  Use of assistive devices for ambulation and for activities of daily living may be indicated. Braces and appropriate footwear may also be of some use. A cane can be used in the opposite hand for OA of the hip, or a cane in the hand of comfort may be helpful for OA of the knee. The patient can be taught joint protection and energy conservation techniques. Other physical therapy modalities include electrotherapy and thermotherapy.

• Occupational Therapy: Evaluation of performance of activities of daily living and retraining can be assisted by the occupational therapist. Emphasize joint protection techniques. Hand splinting, especially of the first carpometacarpal joint, may be indicated.

• Recreational Therapy: A home exercise program that incorporates all of the above treatment principles could be designed and implemented to help the patient retain mobility.

Surgical Intervention: Surgical intervention may be indicated. Types of procedures vary according to the site and the degree of involvement. Various surgical interventions include the following:

• Surgical interventions for OA of the knee

• Arthroscopic lavage - Using a saline lavage to wash out the joint

• Joint realignment (realignment osteotomy)

• Joint fusion (arthrodesis) - Surgically fusing the joint to eliminate motion

• Joint replacement (arthroplasty)

• Surgical interventions for OA of the hip

• Joint realignment (realignment osteotomy)

• Joint fusion (arthrodesis) - Surgically fusing the joint to eliminate motion

• Joint replacement (arthroplasty)
  • Hip replacements generally are classified as either hemiarthroplasty (ie, replacement of the femoral side of the hip joint, while leaving the patient's acetabulum intact) or total hip arthroplasty (replacement of both the femoral side of the hip joint and the acetabulum).

  • Further classification often involves specification of the specific hardware used (eg, unipolar prosthesis, bipolar prosthesis) and whether or not cement is used to hold the hardware in place.

Consultations: Consultation with an orthopedic surgeon sometimes may be needed. Rheumatology consultation is indicated if an alternative diagnosis (eg, rheumatoid arthritis) is suggested.

Other Treatment (injection, manipulation, etc.): Intra-articular steroid injections may provide pain relief and have an anti-inflammatory effect on the affected joint. They generally result in clinically and statistically significant reduction in osteoarthritic knee pain as soon as 1 week after injection. The effect may last, on average, anywhere from 4-6 weeks per injection, but this benefit is unlikely to continue beyond that time frame (Godwin, 2004). Some controversial evidence exists regarding frequent administration and subsequent possible damage to cartilage (chondrodegeneration). Therefore, usually no more than 3 injections are recommended per year in any one osteoarthritic joint.

Intra-articular injection of sodium hyaluronate (ie, hyaluronic acid [HA], hyaluronan), also referred to as viscosupplementation, has been shown to be safe and effective for the symptomatic relief of knee OA. The largest meta-analysis of 76 controlled clinical studies using intra-articular HAs was recently published and updated by the Cochrane Collaboration. This class of therapy was concluded to be effective and safe in patients with knee OA (Bellamy, 2006).

To date, the US Food and Drug Administration (FDA) has approved 5 intra-articular HAs for the treatment of pain associated with knee OA. These include both naturally extracted, non–cross-linked sodium hyaluronate products (Hyalgan, Supartz, Orthovisc, and Euflexxa) and 1 cross-linked sodium hyaluronate product known as hylan G-F 20 (Synvisc). Euflexxa is the only product derived from a fermentation process (Streptococcus), while the source material for the other 4 products is chicken combs. At present, no distinct advantage or disadvantage is associated with either source of HA production. Some differences between the viscosupplements do exist in the FDA-approved prescribing information. For example, Hyalgan and Synvisc have labeling that establishes their safety for repeat treatment while other products have the precaution statement “… the safety and efficacy of repeat treatment has not been established.”

The HA class in general has demonstrated a very favorable safety profile for the chronic pain management of knee OA, with the most common adverse event being injection site pain. While any intra-articular injection (all HA products and steroids) may elicit an inflammatory response and possible effusion, a clinically distinct acute inflammatory side effect (ie, severe acute inflammatory reaction [SAIR] or intra-articular HA–associated pseudosepsis) has been described. However, both preclinical and clinical data provide compelling evidence that this reaction is limited to only the cross-linked hylan G-F 20 product and may have an immunologic mechanism of action. Molecular weight per se has not been found to correlate with efficacy (eg, higher or lower viscosity does not equate with better or worse clinical outcomes). Interestingly, the duration of residence of an intra-articular injection (days) cannot explain the prolonged clinical benefit (months), and, accordingly, subsequent biological mechanisms have also been proposed that may play an important role in the clinical benefit.

In the United States, HAs are classified as medical devices rather than drugs. Although the exact mechanisms of action for their symptomatic relief are unknown, several possibilities exist, including direct binding to receptors (CD44 in particular) in the synovium and cartilage that can lead to several biological activation pathways. These mechanisms of action can include increased endogenous production of hyaluronate and aggrecan by the joint, a mechanical barrier to activation of nociceptors, inhibition of pain mediators (eg, PGE, bradykinin) anti-inflammatory effect (eg, inhibition of proinflammatory cytokine activity, inhibition of inflammatory cell function), a beneficial effect on immune cells, an antioxidant effect, and restoration of physical characteristics of the synovial fluid (viscoelasticity). Viscosity can serve to help facilitate the cushioning and lubricating characteristics of the joint during slow movements, while elasticity blunts deforming forces (compression and resistance to shear forces) during rapid motions.

As reviewed by Goldberg and Buckwalter, preclinical support is available for most of the HAs, as well as clinical evidence (particularly for Hyalgan) using arthroscopy, microscopy, and blinded morphologic assessments and weight-bearing radiographs for assessing joint space narrowing. Intra-articular HAs may also possibly be chondroprotective early in the development of OA (Goldberg, 2005). However, additional studies would seem to be warranted to further explore the ability of HAs to intervene in the disease processes associated with OA. Certainly, a single product with both symptomatic and disease-modifying characteristics, even if only in some patient populations, would be a valuable option in the management of knee OA.

	MISCELLANEOUS	Section 9 of 11
Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Pictures Bibliography

Medical/Legal Pitfalls:

• One potential source of medicolegal action against the physiatrist is the potential for misdiagnosis of an underlying medical problem that causes joint pain as OA. Administration of NSAIDs can lead to GI bleeding, especially if risk factors for GI bleeding are present. Allergic reactions to medications are also possible. Prescription of open-chain kinetic exercises, particularly with respect to quadriceps strengthening, carries the potential for worsened pain and, thus, the potential for medicolegal action on the part of the patient against the physiatrist.