Loose Bodies
NHS Tayside RefGuide
Warning
Who to refer
- Patients with history of recurrent locking and a mobile lump in the knee, combined with good radiographic evidence of a loose body
- For recurrent locking or significantly symptomatic patients, surgical synovectomy may help.
How to refer
- SCI Gateway/Orthopaedics/Knee
- If the patient is under the care of NHS Physiotherapy, investigations and onward referral to knee service, if appropriate, will be organised by Physiotherapy service without the need for further GP intervention.
Information to include when referring
- Duration, any cause of symptoms
- Site/spread and if pain constant or intermittent, and/or walking at night
- Active and passive ROM
- Treatment to date
- XR/MRI results.
General advice
- Many calcified bodies in and around the knee commonly over-diagnosed / mis-diagnosed as “loose bodies” on x-rays and are mistakenly thought to be a source of knee pain.
- Around two-thirds people have a fabella – an accessory sesamoid bone in the proximal tendon of the lateral gastrocnemius –normal anatomic variant and is not “loose” within the knee joint.
- Fragments of bone, cartilage and combined bone and cartilage can come from surface damage due to injury or joint degeneration. Some loose bodies can occur for no obvious apparent reason. Small cartilaginous bodies can become ossified or calcified for reasons not well understood. Loose bony, cartilaginous or osteocartilaginous bodies may become enveloped by fibrinous tissue, synovium or fatty tissue (infra- or supra-patellar fat pad) which renders them fixed rather than “loose”. Some may escape to the back of the knee joint (posterior recess) and remain there without causing any problems. Some escape into a Baker’s cyst.
- Synovial chondromatosis is an uncommon condition where the synovial lining of the knee joint produces (often multiple) nodules of cartilage which can then calcify or ossify and become detached producing loose bodies. Secondary osteoarthritis from surface trauma may ensue. Those affected may have mechanical symptoms from loose bodies and/or popliteal knee pain, swelling and stiffness. Some asymptomatic cases may be diagnosed incidentally on an x-ray or MRI scan.
Symptoms and sign
- True “loose” bodies in the knee can cause occasional sharp pains, crunching, giving way and true locking of the knee if they become trapped within the tibiofemoral joint.
- Usually a history of a mobile lump appearing in the joint line or suprapatellar pouch which may be able to move manually.
Initial management
- Pain control Analgesia & NSAIDs as appropriate
- Walking aid, advise weight loss if appropriate
- Refer to MSK Physiotherapy.
Primary Care diagnostics
- To determine if a calcified body is “loose”, serial x-rays can demonstrate change in position.
- MRI can determine if the lesion is intra- or extra-articular, the number of loose bodies present and any potential underlying cause or donor site.