Diagnosis (1 of 2)

Multiple guidelines eg. RACGP 2018, NICE 2014, EULAR, Victorian Model of Care for Osteoarthritis of the Hip and Knee 2018 and Australian Clinical Care Standard (ACSQHC) for Knee OA 2017 all suggest:

“Plain radiograph is not required to make a diagnosis of hip and knee OA, but could be
considered for atypical presentations”

However, The Australian Orthopaedic Association has declined to endorse the current ACSQHC Osteoarthritis of the Knee Clinical Standard as it does not support the use of x-rays as a diagnostic too

Diagnose Knee OA with following criteria:

• Over 45 years-old;
• Use/activity-related pain;
• +/- short-lived morning stiffness (<30 mins)
• No detectable warmth

Plus: -Crepitus
-Restricted knee ROM (flex/ext),
-Bony enlargement

Whilst prevalence of knee OA is higher, hip OA still has a high prevalence estimated at 28%  in people over the age of 45.

Groin pain is considered most commonly reported symptom, but can also refer to buttock, thigh (particularly lateral), distal leg and knee.

Prevalence of knee pain caused by hip OA unknown, most literature related to case studies, including examples of patients having undergone revision TKR as knee pain remained-with knee pain subsequently resolved after THR.

Clinical prediction rules for hip OA:
Sutlive et al (2008):

• self-reported squatting as aggravating factor
• active hip flexion causes lateral hip pain
• pain with quadrant/scour test
• active hip extension painful
• passive hip IR <25

If 3 or more factors present; increases +ve LH ratio of hip OA 5.2 (5-10: moderate shift in probability)

If at least 4, +ve LH ratio of 24.3 (>10: large and often conclusive shift in probability)-compared numerous different subj and obj factors with radiographic OA

Altman et al (1991):

• Hip IR <15 and
• Hip flex <115

OR

• Aged 50 or over
• hip IR >15
• pain with hip IR
• AM stiffness <1 hour

Sensitivity 86% and specificity 75% for hip OA

Case studies/power points on this, including cancer-primary and metastatic disease (in depth case study bony mets from breast cancer, need to do equivalent for prostate); inflammatory arthritis (case study with SLE); gout; vascular; infection eg OM; charcot; hip; lumbar (Case study); SONK; PVNS; septic arthritis; neurological etc.

Consider history of trauma such as MVA or fall.

Also be aware of osteoporosis or risk or osteoporosis (e.g. postmenopausal women)

Assess for haematoma, odedma and signficant pain

Ottawa knee rules indication for imaging of knee
-age over 55   OR
-isolated tenderness of patella (no bone tenderness of knee other than patella)   OR
-tenderness of the head of fibula   OR
-cannot flex to 90 degrees   OR
-unable to weight bear both immediately and in the ED for 4 steps

As well as fracture at knee, consider fracture NOF

Soft tissue injury-quads or patellar tendon rupture
-ligament injury

Deep vein thrombosis or DVT can lead to life threatening complications such as pulmonary embolis. Incdience of venous thromboembolism is estimated to be 1 per 1000 people per year, with approxiamtely 2/3 of these being DVTs. DVTs are slightly more common in males than females and incidence rises with increasing age.

Risk factors for DVT:
-acute infection
-cancer
-stroke or paralysis
-previous DVT
-congestive heart failure
-pregnancy
-dehydration
-varicose veins
-increasing age
-prolonged immobility
-hormone treatment
-long air travel
-acute inflammatory bowel disesae
-rheumatological disease
-nephrotic syndrome
-oral contraceptive pill
-obesity

History and clinical exam are not reliable ways of diagnosing DVT as patients can be asymptomatic. Symptomatic patients may present with lower extremity pain, warmth, calf tenderness and asymmetric lower extremity swelling-however non-specific and suggest need for further investigation rather than definitive diagnosis

Wells score for liklihood of DVT: (NB-sensitivity 77-98%, specificity 38-58%)

Normally diagnosed via either D-dimer or venous US or combination

If have calf pain, asymmetric swelling, redness, warmth or tenderness to palpation-recommend referring on for further investigation

Neurogenic claudication relates to pain from a neural source-often associated with lumbar stenosis. Vascular claudication is due to restricted blood flow.

Neurogenic versus vascular

Adapted from GP Notebook https://gpnotebook.com/en-au/simplepage.cfm?ID=x20170726144238191130

Cluster of symptoms better predictor:

Neurogenic: symptoms triggered with standing, relieved with sitting, located above knees and positive shopping cart sign (walking better when using shopping trolley) strong evidence to suggest intermittent neurogernic rather than vascular claudication

Vascular: Symptoms relieved relieved with standing alone and located below knees much more likely to be vascular then neurogenic claudication

From Nadeau M, Rosas-Arellano MP, Gurr KR, et al. The reliability of differentiating neurogenic claudication from vascular claudication based on symptomatic presentation. Can J Surg. 2013;56(6):372-377. doi:10.1503/cjs.016512

Inflammatory arthropathies includes RA and psoriatic arthritis

Psoriatic arthritis is present in 20-25% of people with psoriasis; and a prevalence overall of 1-2 per 1000 people. Approximately 70% of people with psoriatic arthritis will have psoriasis.

Involvement of DIP can be present in psoriatic arthritis or OA, however presence of Heberden’s nodules is characteristic of OA. RA typically affects MCP and PIP.

RA is associated with soft, warm, ‘boggy’ and tender joints; whereas swelling of  OA joints is often hard and bony

RA is typically peripheral joints rather than low back, and is suspected when there is inflmmatroy arthritis invovling three or more joints, postive RF and anti- CCP testing, elevated CRP or ESR, with symptoms present more than 6 weeks, morning stiffness lasting longer than 30 minutes; and other inflammatory conditions excluded

Septic arthritis is an infection in the joint

Risk factors include:
-advance age
-pre-exisiting joint disease
-recent joint surgery or injection
-skin or soft tissue infection
-IV drug use
-indwelling catheters
-immunosuppression (including diabetes)

Normally occurs via infection carried in the blood but can be due to direct entry of bactiera into a joint e.g. trauma, injection; or from adjcent tiisues e.g. osteomyelitis.

Patients usually have an acute, single swollen painful joint. Joint pain, swelling, warmth, and restricted movement are presetn in approx 805 ofpateints with sepctic arthritis.
Please note: most patients with septic arthritis are febrile, although older patients may be afebrile

Knee is the affected joint in over half of cases.

Diagnosis is via synovial fluid analsysis and culture (i.e. joint aspiration). Bloods and imaging should also be obtained-imaging is to evaluate current bone and joint disease and not for diagnosing septic arthritis

Differentials include: gonococcal arthritis, lyme disease , TB, gout, pseudo gout, reactive arthritis, OA flare, acute traumatic arthritis (haemarthrosis associated with trauma to the joint)

Pigmented villonodular synovitis (PVNS) also known as Tenosynovial giant cell tumour (TGCT).

Rare proliferative lesion of synovial tissue. Some debate whether an inflammatory process or benign neoplasm

Most common in knee but can be in other joints.

Can present with pain, swelling, arthritis and haemarthrosis.

Disease itself is a hypervascular proliferative synovium, limits joint function and may erode adjacent bone

Main treatment-resection of synovium

If receive referral with PVNS-refer on (ortho or rheum or both)

Spontaneous osteonecrosis of the knee

-suspected in middle aged and elderly patients with sudden on set spontaneous knee pain

• Patient with a limp 7 times more likely to have hip or hip and lumbar spine component to problem than lumbar spine disorder alone
• Groin pain 7 times more likely to have hip or hip and lumbar than lumbar alone
• Painful and limited hip IR key clinical predictor of hip pathology-14 times more likely to have hip pathology than lumbar; recognised by various guidelines in diagnosing hip OA (All from Brown et al 2004)
• Weakness hip abd-bear in mind L4/5 supplies glut med-could also look at walk on heels/walk on toes to check for myotomal weakness if suspicious of lumbar component
• Pain with weight-bearing-not just with walking but specifically as puts weight on effected side suggests hip

Cosndier in patients with history of back pain

Presence of pins and needles or numbness may suggest radicular symptoms

Can present as a new swollen joint, often similar to septic arthritis, however cultures are negative.

Most patients with reactive arthritis have genitourinary or gastrointestinal signs or symptoms; eye symptoms e.g. conjunctivitis, or skin or mucous membrane lesions.

Described as an arthritis following an infection elsewhere in the body, often one -to four weeks post infection

Relatively rare and typically younger adults

In at least 50% of patients, all symptoms resolve within 6/12; and most patients symptoms resolve within one year.

GOUT 
Gout affects approx 1% of population

Males > females, more common in middle aged (>40 years)

Consider especially if  obese, drink alcohol, have renal impairment, have HTN, and/or taking a diuretic

PSEUDOGOUT

Metabolic monoarthropathy
Deposition of calcium pyrophosphate dihydrate (also called CPPD)

More common in elderly female > male

Assocaited strongly with OA and acute synovitis
Knee most common, but can be any joint

Depositis in articualr joints and fibrocaritlage -chondrocalcinosis and can be asymptomatic

Thought to be two types:

• Primary: associated with preservation of articular cartilage initially
• Loose bodies from synovial metaplasia
• Osteoarthritis occurs secondary to irritation in joint from loose bodies
• Secondary: cartilaginous loose bodies are from pre-existing degenerative joint surface changes

• Benign disorder of the synovial lining
• Characterized by loose cartilaginous bodies
• Becomes osteochondromatosis when cartilaginous bodies ossify (happens in 70-95% of cases)
• Can be diagnosed on x-ray when osteochondromatosis, (typically joint effusion and ossified chondroid loose bodies), erosions less common in knee than hip
• CT or MRI recommended when synovial chondromatosis is clinically suspected and radiographs either normal or only joint effusion

Differentiating primary versus secondary:

• Intra-articular bodies larger in 2nd compared with primary
• Less loose bodies in 2nd compared with primary
• Bigger variation in size and shape of loose bodies in 2nd compared with primary
• Often severe degenerative change on x-ray with 2nd as loose bodies due to osteoarthritic changes