gms | German Medical Science

Introduction: Osteoarthritis (OA) is a group of mechanical disorders leading to joint components degradation, including articular cartilage and subchondral bone. Symptoms include joint pain, tenderness, stiffness, and effusion. A variety of causes are known of which hereditary, developmental, metabolic, and mechanical may initiate processes leading to loss of cartilage (2). OA is the most common form of arthritis affecting aged population and a main cause of disability. Incidence and prevalence of knee OA is rising by increasing average age of general population and increasing obesity (3). OA affects about 44% of people older than 80 years age (4). The prevalence rate of knee OA was 9.95% in males and 37.76% in females above 65 years in another study (5). In a third study, knee OA was estimated to affect 19.2% to 27.8% of the population aged 45 or above (6). The overall prevalence of knee OA worldwide increased to 37.4% in people of 60 years old or older (7).

Diagnosis of knee OA is either clinical or radiological or sonographic.

Clinical criteria include

1.

Knee pain for most days of prior month

2.

Crepitus on active joint motion

3.

Morning stiffness ≤30 min

4.

Age ≥38 years old

5.

Bony enlargement of the knee on examination.

1, 2, 3, 4 or 1, 2, 5, or 1, 4, 5 are needed to establish diagnosis (6).

Clinical and Radiographic

1.

Knee pain for most days of prior month

2.

Osteophytes at joint margins

3.

Synovial fluid typical of osteoarthritis

4.

Age ≥40 years old

5.

Morning stiffness ≤30 min

6.

Crepitus on active joint motion

1, 2 or 1, 3, 5, 6 or 1, 4, 5, 6 are needed to establish diagnosis (6).

Sonographic signs of OA according to frequency were effusion, followed by synovial hypertrophy, cartilage parameters, vascularity, Baker’s cysts, osteophytes, tendon and ligament abnormalities (hypoechogeneicity, tendon thickening), meniscal changes, bursitis, erosions and panniculitis (8). US is more sensitive than conventional radiography in the detection of osteophytes and joint space narrowing. Furthermore, it is able to detect effusion and synovitis better than clinical evaluation (9). Evaluation of knee effusion depends on examination of three recesses: suprapatellar, parapatellar lateral, and parapatellar medial. As fluid is displaceable, care should be taken to avoid pressure with the probe. Knee should be 30 degree flexed with quadriceps contraction. Fluid is differentiated from synovial fluid by compressibility and lack of power Doppler activity (10).

Treatment of knee effusion includes: rest, cold compresses, elevation, NSAIDS and aspiration (11). Aspiration is an invasive maneuver and, therefore, many patients refuse to do it. However, it provides a temporary relief of symptoms and microscopic evaluation of synovial fluid to establish diagnosis, but it still has a high rate of recurrence. Beneficial effect of aspiration is not yet confirmed by a randomized controlled study (12).

Spironolactone is a specific pharmacologic antagonist of aldosterone, acting primarily through competitive binding of receptors at the aldosterone-dependent sodium-potassium exchange site in the distal convoluted renal tubule. Spironolactone causes increased amounts of sodium and water to be excreted, while potassium is retained has a mild antihypertensive effect and can be used in normotensive persons. In a previous study, it was used alone in a dose of 25 mg for four weeks with no effect on blood pressure (13).

Spironolactone is known to have no effect on uric acid metabolism except in some reported cases with chronic renal disease (14).

Spironolactone is used before in treatment of ascites of liver cirrhosis and pleural effusion due to hepatic cause, nevertheless, there is not enough data about its use in treatment of knee effusion (15, 16).

Methods: This study was carried out on 200 patients attending the outpatient clinic of Rheumatology and Rehabilitation Department of Sohag University Hospital, Egypt during the time period from October 2014 to February 2015, who aged 40 years or above with unilateral knee effusion related to osteoarthritis based on clinical examination, musculoskeletal ultrasonography (US) and synovial fluid analysis. Group 1 consisted of 50 patients received spironolactone 25 mg daily for 2 weeks, in group 2 50 Patients took Ibuprofen 1200 mg daily for two weeks, in group 3 50 patients used cold compresses two times daily for two weeks, and in group 4 50 patients received placebo for the same time duration. US device was LogicE General Electric linear probe 8-12 MHZ. Fluid more than 4mm thickness in sagittal view, 30 degree knee flexion was considered as effusion (1). Decrease in fluid below 4mm thickness was considered as a complete improvement, any decrease less than this was considered as partial improvement. Creatinine clearance and serum Potassium, Sodium were done to all study candidate before inclusion in the study.

Results: The mean age of the participants was 51.2±8.1 years. The mean duration of effusion was 16.5±3.6 days. In group 1, 66% had complete improvement, 20% partial improvement and 14% no response. In group 2, 24% had complete improvement, 12% partial improvement and 64% no response. In group 3, 28% had complete improvement, 14% partial improvement and 58% no response. In group 4, 6% had complete improvement, 10% partial improvement and 84% no response.

Conclusion: Low dose spironolactone was a safe and effective medical treatment for OA related knee effusion, especially in mild and moderate degree and when precautions are followed.