Knee pain (assessment)

• Younger adults (18-50Y): Patellofemoral pain, trauma (cruciate and collateral ligament sprains, meniscal tears), joint hypermobility syndrome, bursitis, inflammatory arthritis, septic arthritis, early OA (previous injury), medial plica syndrome

• Older adults (>50Y): OA, gout and pseudogout, Baker's cyst, referred pain from hip OA, degenerative meniscal tear, septic arthritis​

• Uni / bilateral (patellofemoral pain often bilateral) / other joints?

• OA: knees, hips, small joints of the hands (first MCPJ and IPJ), and the 1st MTPJ are most commonly affected (but any synovial joint can be involved, and usually only one or a few joints are problematic at any one time)

• RA: typically symmetrical synovitis of the small joints of the hands and feet (although any synovial joint may be affected)

• Onset, location, duration, severity, and quality (type) of the pain

  • Spontaneous onset severe pain with absence of trauma: infection, pathological fracture, or osteonecrosis

  • Anterior: patellofemoral pain most common cause

  • Posterior: e.g. Baker's cyst, DVT

  • Lateral: e.g. iliotibial band syndrome and osteoarthritis

  • Medial: e.g. OA, pes anserine bursitis, and rarely a medial plica or osteonecrosis

• Aggravating / relieving factors: pain aggravated by kneeling in older adults: prepatellar bursitis or patellofemoral OA (or the presence of a large knee effusion due to another cause)

• Persistent or nocturnal pain: tumour, inflammatory arthritis, or severe OA

• Swelling: acute (without trauma): septic or inflammatory arthritis (e.g. gout or RA); recurrent small knee effusions: patellofemoral pain, OA, patellar subluxation, and meniscal injury (degenerative meniscal tears can occur with no or minimal trauma in middle-aged or older people)

• Joint stiffness: Morning stiffness typically ≤30 min in OA; maybe longer in inflammatory arthritis

• Locking / giving way without trauma, locking: consider loose body (e.g. in OA or osteochondritis dissecans), a discoid lateral meniscus, or a degenerative meniscal tear. True giving way: patellar subluxation or dislocation, or a discoid lateral meniscus (as well as with meniscal injuries). Sensation of giving way: patellofemoral pain or OA

• Crepitus, snapping, or clicking: limited value in identifying the cause. All can occur with patellofemoral pain; crepitus may also occur in OA and prepatellar bursitis. Ask about any history of previous injuries, surgery, or medical conditions e.g. gout, pseudogout, RA, other inflammatory arthropathies, or OA

Examination

• Inspect/palpate: erythema, warmth, deformity, bruising, quad atrophy, tenderness, swelling (bony, bursal, soft tissue, joint effusion), bony swelling around joint margins (often palpable in knee OA), persistent, increasing, or unexplained (red flag for a tumour, esp. if away from the joint line), tibial tuberosity (Osgood-Schlatter's disease), over body of patella without joint effusion (prepatellar bursitis or Sinding–Larsen–Johansson syndrome)

• Extend/flex (normal range: 0 deg of extension to 135 degrees of flexion). Hyperextension may indicate joint hypermobility syndrome

• Ipsilateral hip/lumbar spine: hip and spinal pathology causing referred pain to the knee, particularly in children

• Other joints, lymphadenopathy, other signs of infection as req (OA, inflammatory arthritis, and infection e.g. septic arthritis)

Indications for MRI

• Only recommended if plain Xray is normal, or a specific pathology is sought

• <60Y with suspected meniscal tear, ligament injury, suspicious lump or recurrent anterior knee pain

• >65Y, MRI may demonstrate a co-incidental meniscal tear which may not be contributing to symptoms

Resources: Knee pain - assessment (CKS), Joint pain (NHS Choices), Knee pain (Mayo clinic)

OA

• OA can be diagnosed clinically without further investigation if the patient is aged >45Y, they have activity-related joint pain and morning stiffness lasting <30 mins. If investigations are warranted, plain X-ray is the first choice. MRI should not be routinely requested and blood tests are not required.

Resource

• Osteoarthritis: care and management (NICE CG177, 2014)

Baker's cyst

• Baker's cyst (NHS Choices), Baker's cyst (CKS)

Meniscal tear

• Degenerative meniscal tear (CKS), A clinical prediction rule for meniscal tears in primary care: development and internal validation using a multicentre study (BJGP, 2015)

Iliotibial band syndrome

• Iliotibial band syndrome (Runner's world)

Knee fracture / dislocation

• Knee fractures and dislocations (Patient.info), Dislocated kneecap (NHS Choices)

Knee replacement

• Knee replacement (NHS Choices)

Osgood-Schlatter disease

• Osgood-Schlatter disease (CKS), Osgood-Schlatter disease (Patient.info)

Osteochondritis dissecans

• Osteochondritis dissecans (Patient.info)

Patellofemoral pain / Patella Tendinopathy

• Patellofemoral pain (CKS)

• Patello-Femoral Pain (PFP) information booklet (Guy's and St Thomas', 2013), Exercise therapy for adolescents and adults with pain behind or around the kneecap - patellofemoral pain (Cochrane review, 2015), Patellofemoral pain: an update on diagnostic and treatment options (Curr Rev Musculoskeletal Med, 2013), Physiotherapy management of patella tendinopathy - jumper's knee (Journal of Physiotherapy, 2014)

Pre-patella bursitis​

• Pre-patellar bursitis (CKS)