Joints and pain
Low Back Pain: An Orthopaedic View, Red Flags and Treatment
In short
Low back pain is very common and, in most people, comes from strain of the muscles, joints or discs rather than a serious disease; it usually improves within a few weeks. The first steps are staying active, simple self-care and exercise. Imaging such as an X-ray or MRI is not routinely needed unless warning signs (red flags) are present or the result would change treatment.
What is low back pain?
Low back pain is pain felt in the lower part of the spine. Most cases are non-specific, which means no single serious cause can be found, and the pain is usually linked to muscle strain [1][4].
Low back pain usually improves within a few weeks, but it can sometimes last longer or keep coming back [1].
From an orthopaedic point of view there are also specific structural causes: a disc herniation pressing on a nerve, age-related arthritis of the facet joints, narrowing of the spinal canal (spinal stenosis), slipping of one vertebra over another (spondylolisthesis) and compression fractures caused by osteoporosis [3]. Serious causes such as a fracture, cancer or infection are rare [1].
What are the symptoms?
Low back pain can feel different from person to person. Common symptoms include [1][3]:
- Pain and stiffness in the lower back, often worse with certain movements
- Pain spreading into the buttock and leg when a nerve root is irritated (sciatica)
- Pain that makes everyday activities difficult
- In some people, pain that lasts beyond a few weeks or keeps coming back
Causes and risk factors
The most common cause is muscle strain from activity. Other causes include tears, herniation or wear of the discs, arthritis of the facet joints, spinal stenosis, spondylolisthesis and curvature of the spine (scoliosis) [3].
The main factors that raise the risk are [3]:
- Ageing and wear-related changes in the spine
- Smoking, which speeds up disc degeneration
- Being overweight
- Poor lifting technique and overexertion
Diagnosis: do I need an MRI?
The basis of diagnosis is a careful history and examination. The doctor asks about warning signs of serious disease and checks leg strength, sensation and reflexes to see whether a nerve is being compressed [2][4].
International guidelines advise against routine imaging and recommend it only when serious disease is suspected [4]. The UK national guideline from NICE likewise advises against routine imaging in first-line care and suggests considering it in specialist settings only if the result is likely to change management [2].
The main warning signs (red flags) doctors look for are [1][2][5]:
- Older age, a significant fall or injury, or long-term corticosteroid use (these raise the chance of a vertebral fracture)
- A past history of cancer or unexplained weight loss
- Fever, chills and feeling generally unwell (possible infection)
- Pain that is worse at night
- New weakness in the legs, numbness around the genitals or back passage, or changes in bladder or bowel control
Treatment: conservative care first
Most people with low back pain get better with simple measures. Guidelines recommend reassurance that the outlook is usually good, avoiding bed rest and returning to normal activities [1][4]:
- Staying active and continuing daily activities as much as possible [1][4]
- Short-term anti-inflammatory painkillers; NICE does not recommend paracetamol on its own, or opioid medicines for long-term low back pain [1][2]
- Heat or cold packs [1]
- Exercise: group exercise programmes, stretching and strengthening; for chronic low back pain, exercise therapy and psychological support are recommended [1][2][4]
- Manual therapy (manipulation, mobilisation or massage) only as part of a treatment plan that also includes exercise [2]
Which treatments are not recommended, and when is surgery considered?
The NICE guideline does not recommend belts or corsets, foot orthotics, traction, acupuncture or ultrasound therapy for low back pain [2].
Surgery is for a small group of patients. If sciatica spreading down the leg continues despite non-surgical treatment and the imaging findings match the symptoms, surgery to relieve pressure on the nerve may be considered [2]. For back pain itself, surgery is usually discussed only after 6 to 12 months of appropriate non-surgical treatment [3]. For non-specific low back pain, NICE does not recommend spinal fusion outside clinical trials; radiofrequency denervation may be considered for selected people with chronic pain [2].
Recovery
Most low back pain eases within a few weeks [1]. If the pain has not improved after about 4 weeks, or there are signs of nerve compression, referral to a specialist is recommended [4].
Support to return to work and normal daily activities is an important part of recovery [2]. Pain can come back from time to time; regular exercise and an active lifestyle make these episodes easier to manage [1].
When low back pain lasts a long time, psychosocial factors such as stress, work-related difficulties and worries about the pain matter as well as the spine itself, and guidelines recommend that these are assessed too [4].
When to see a doctor urgently
Go to an emergency department without delay if any of the following occur [1]:
- Weakness or numbness in both legs
- Numbness around the genitals or back passage
- New problems controlling the bladder or bowels, or being unable to pass urine
- Chest pain together with back pain
- Pain that started after a serious accident, fall or blow
- Severe pain together with fever, chills or feeling unwell
Frequently asked questions
+Do I need an MRI for low back pain?
Usually not. Guidelines do not recommend routine imaging when there are no warning signs; imaging is used when serious disease is suspected or when the result would change treatment [2][4].
+How long does low back pain last?
Low back pain usually improves within a few weeks. In some people it lasts longer or comes back from time to time [1].
+Should I rest in bed with low back pain?
No. Staying active and keeping up normal activities as much as possible is recommended; bed rest is not advised [1][4].
+What are the red flags for low back pain?
Leg weakness, numbness around the genitals, changes in bladder or bowel control, fever, unexplained weight loss and pain after a serious injury need urgent assessment. Older age and long-term corticosteroid use raise the chance of a vertebral fracture [1][5].
Sources
- [1]Back pain — NHS (nhs.uk), 2026.
- [2]Low back pain and sciatica in over 16s: assessment and management (NG59) — National Institute for Health and Care Excellence (NICE), 2016, updated 2026.
- [3]Low Back Pain — American Academy of Orthopaedic Surgeons (OrthoInfo).
- [4]Clinical practice guidelines for the management of non-specific low back pain in primary care: an updated overview — European Spine Journal (Oliveira CB, et al.), 2018.
- [5]Red flags to screen for vertebral fracture in people presenting with low back pain — Cochrane Database of Systematic Reviews (Han CS, et al.), 2023.
This article is general information and does not replace an examination or personal medical advice. In an emergency, go to the nearest emergency department.