Assessing Hip & Knee Arthritis: A GP's Guide

Assessing Hip Arthritis in General Practice

Hip osteoarthritis has a characteristic symptom pattern once you intentionally look for it. The key symptom is deep groin pain, which patients may describe as "in the crease" or "in my thigh," and it is much more predictive of true hip joint pathology than lateral hip pain. Trochanteric (lateral) pain is far more likely to be trochanteric bursitis or gluteal tendinopathy, or an overlying condition in addition to arthritis, and should make you think carefully before labelling it as "just hip OA."

Helpful Hip History Prompts

• Ask specifically about groin pain: walking, turning in bed, getting in and out of a car, and pivoting are common aggravators.
• Clarify shoe and sock difficulty: struggling to put on shoes, socks or trim toenails reliably indicates loss of hip flexion and internal rotation.
• Ask how they get into a car: many will describe "bottom in first, then lifting the leg in with my hands" as a compensatory manoeuvre for stiffness and pain.
• Explore sleep: night pain, especially when lying on the affected side, and difficulty turning in bed are common and often drive patients to seek help.
• Walking and function: reduced walking distance, needing to "plan" short walks, and avoiding longer outings (shopping centres, airports, holidays) are typical.
• Cycling or stationary bike: obligate external rotation (toes and knee pointing out) when trying to cycle, or an inability to sit squarely on the saddle, suggests loss of internal rotation and flexion.
• Posture and the spine: many patients adopt a slightly flexed, "hunched" posture to unload the hip, which increases lumbar load and may worsen pre‑existing spinal symptoms.

Hip Examination & Imaging

Focused Hip Examination

• Observe posture and gait from the door: a flexed, slightly stooped posture with a shortened step length on one side is common in significant hip OA.
• Leg length: true leg length discrepancy can occur from joint space loss and contracture; many patients will feel "shorter on one side."
• Range of motion: limitation or loss of internal rotation in flexion is usually the earliest and most reliable sign of hip OA.
• Pain on passive internal rotation and flexion–adduction–internal rotation often reproduces their groin pain.
• Pelvic tilt: chronic unilateral disease can produce a pelvic obliquity, seen as waist crease asymmetry or apparent leg length difference.
• Trendelenburg: a true Trendelenburg sign or pronounced Trendelenburg gait is more classically associated with abductor weakness and trochanteric bursitis rather than isolated intra‑articular osteoarthritis.

Imaging for Suspected Hip OA

For first‑line imaging, request an AP pelvis centred on the symphysis, including both hips and the entire pelvis. This allows comparison with the contralateral hip and assessment of leg length, pelvic tilt and overall morphology. Typical features of osteoarthritis to look for on hip and knee X‑rays are outlined in more detail in the article "Osteoarthritis on Hip and Knee Xrays" on this website.

If your patient clearly has symptoms but the film is equivocal, early referral is appropriate rather than escalating to MRI in the first instance. MRI is generally reserved for cases where symptoms and X‑rays do not match, or where competing pathology is suspected.

Non‑Operative Measures & Checklist

• Optimise simple analgesia, in combination with GP‑guided use of anti‑inflammatory medication where appropriate.
• Encourage low‑impact activity such as walking within tolerance, stationary cycling (often in slight external rotation), and targeted hip and core strengthening.
• Address weight optimisation, footwear and gait aids early — sometimes even a simple stick in the contralateral hand can meaningfully reduce symptoms.
• Injections such as PRP, steroids or Euflexxor are generally short‑term solutions which may assist with planning and timing for surgery. They should be performed at least three months before an anticipated joint replacement, as injections within this window have been shown to increase the risk of infection by approximately six‑fold.

Hip OA — GP Checklist

Assessing Knee Arthritis in General Practice

Knee osteoarthritis often presents later than hip OA, but pattern recognition still helps you triage severity and likely alignment subtype. A limp on walking is extremely common, and most patients will have clear functional triggers if you ask about stairs, uneven ground and getting up from low positions.

Key Knee History Points

• Walking pattern: look for a limp and ask whether the leg seems to "swing out" or externally rotate as they walk; many patients hold the knee in a slightly flexed, externally rotated position to avoid terminal extension pain.
• Stairs: difficulty going downstairs is often more prominent than going up, as eccentric quadriceps control under load stresses an arthritic joint.
• Uneven ground: worsening pain and a sense of insecurity or giving way on irregular surfaces suggest poor dynamic control around a stiff or painful joint.
• Rising from the ground or low chairs: difficulty or the need to push with the arms is typical of more advanced disease.
• Giving‑way: a sensation of the knee "slipping" or "buckling" can reflect pain inhibition, mechanical catching from osteophytes, or co‑existent meniscal pathology.

Subtypes: Varus, Valgus and Patellofemoral‑Predominant

Approximately 70% of degenerative knee arthritis cases are predominantly varus (medial compartment), around 20% are valgus (lateral compartment), and roughly 10% are predominantly patellofemoral‑predominant. Each behaves a little differently.

Varus (medial) OA

• More pain on the inside of the knee, often worse with walking on flat ground or prolonged standing.
• Bow‑legged appearance may be long‑standing or progressive.

Valgus (lateral) OA

• Lateral joint line pain, often aggravated by side‑to‑side movements and walking on slopes.
• Knock‑kneed appearance; sometimes more obvious difficulty on uneven surfaces.

Patellofemoral‑predominant OA

• Anterior knee pain, worse on stairs (especially down), slopes, squatting, prolonged sitting or rising from a chair ("theatre sign").
• Patients often report more crepitus and "grinding" behind the kneecap.

Knee Examination & Imaging

Knee Examination

• Observe stance and alignment from the door: note whether they stand varus, valgus or relatively neutral.
• Check for a flexion contracture: fixed flexion deformities are very common in established arthritis, and the patient may be unable to achieve full extension even with your assistance. This is a frequently missed sign.
• Assess range of motion and end‑range pain in flexion and extension.
• Palpate the joint lines medially and laterally; localised tenderness usually reflects the predominant compartment involved.
• Look for a Baker's cyst in the popliteal fossa; it is a common finding and usually reflects intra‑articular pathology rather than a separate diagnosis.
• Patellofemoral tests: crepitus on active movement, pain on patellar compression, and discomfort on squatting or stepping‑down manoeuvres support anterior compartment involvement.

Imaging for Suspected Knee OA

First‑line imaging is plain X‑rays: weight‑bearing AP, lateral and skyline (patellofemoral) views are required to properly stage knee arthritis. The same osteoarthritic changes described for hips — joint space narrowing, osteophytes, subchondral sclerosis and cysts — apply.

If X‑rays are normal or near‑normal but symptoms are significant — particularly in a younger patient or where locking, catching and mechanical symptoms dominate — an MRI is the next best step to evaluate for meniscal pathology or other intra‑articular soft tissue lesions. In older patients with clear radiographic OA, MRI is rarely required before referral.

Non‑Operative Measures & Checklist

• Simple analgesia and short courses of anti‑inflammatories, guided by comorbidities.
• Targeted strengthening of quadriceps and hip musculature, ideally via physiotherapy.
• Weight management, activity modification (for example, swapping running for cycling or swimming), and gait aids.
• Injections to the joint are generally short‑lived, and assist sometimes when surgery needs to be delayed. If joint replacement is being considered, injections should be performed at least three months before surgery due to the significantly elevated risk of infection.
• Arthroscopy has almost no role in established arthritis and is mainly reserved for mechanical symptoms in the setting of relatively preserved joint space.

Knee OA — GP Checklist

Referral Pathway

Once you feel that a joint replacement may be required, please reach out with a referral and we will contact the patient directly to arrange an appointment. We review all referrals and imaging prior to the patient arriving and will arrange any further investigations if necessary.

Frequently Asked Questions