Pain after total knee replacement

When pain persists after knee replacement

Total knee replacement (TKR) provides substantial improvement for many patients. For others, however, walking, climbing stairs or resting remain difficult.

Identifying the source of persistent pain helps guide targeted treatment. Genicular nerve radiofrequency and, when indicated, dorsal root ganglion neuromodulation may form part of this pathway.

How common is it?

Persistent pain after TKR is a recognised problem. Wylde and colleagues describe chronic pain in approximately one in five patients, with estimates varying according to definitions and follow-up periods. Pain alone does not establish that the implant is malfunctioning.

Wylde et al., 2018.

Why can the knee continue to hurt?

Several causes may coexist.

Mechanical or joint problems. Instability, component loosening, malposition, altered patellar tracking and stiffness due to arthrofibrosis may cause pain and functional limitation.

Periprosthetic infection. This must be considered when assessing a painful replacement; absence of fever does not exclude it.

Surrounding tissues. Tendons, bursae, scars and soft-tissue impingement may cause localised pain.

Neuropathic pain. Injury or irritation of sensory nerves may cause burning, electric-shock sensations, tingling or pain on light touch. The infrapatellar branch of the saphenous nerve may be involved, sometimes with a painful neuroma.

Pain from other areas. Hip or lumbar spine conditions may contribute to pain felt around the knee.

Nervous system sensitisation. Pain-processing mechanisms may remain unusually responsive, contributing to persistent symptoms even when the implant is stable.

What to describe during your consultation

It matters whether pain has remained unchanged since surgery, changed in character or returned after a period of relief. Assessment considers pain during weight-bearing or stair climbing, rest or night pain, stiffness, swelling and giving way.

Burning, electric shocks, tingling, numbness or pain on light touch may suggest a neuropathic component. These symptoms alone do not locate the lesion: their distribution is assessed alongside sensation, strength and reflexes. New weakness needs assessment in its own right.

Before treatment: identifying the target

Assessment starts with the history: was pain present before surgery, has it never improved, or did it return after a period of comfort?

Examination and investigations are selected accordingly. Orthopaedic assessment may include radiographs, blood tests and joint fluid analysis when needed. Pain assessment also considers scars, peripheral nerves and possible sources outside the knee. An infection or a correctable mechanical problem requires a specific treatment pathway.

A diagnostic genicular nerve block (information in Italian) may support patient selection, without guaranteeing the outcome of radiofrequency treatment.

Genicular nerve radiofrequency denervation

When pain persists and assessment supports a peripheral joint source, thermal radiofrequency denervation of the genicular nerves may be considered.

The procedure targets small nerve branches carrying pain signals from the knee. The superomedial, superolateral and inferomedial genicular nerves are among the most widely studied targets. Target selection must reflect the individual clinical picture and anatomy.

Ultrasound guidance helps identify anatomical landmarks and nearby blood vessels. Ultrasound-guided treatment has also been described specifically after knee replacement.

The aim is to reduce pain and facilitate functional recovery. Studies report encouraging results, but remain small and heterogeneous. A 2026 systematic review included ten studies involving 211 patients, with a moderate-to-high risk of bias. Benefit is possible but not guaranteed; the response and duration of relief vary.

Explore knee radiofrequency treatment (in Italian).

Images of treatment after total knee replacement

When to consider additional L4 dorsal root ganglion neuromodulation

In the pathway proposed by Dr Evangelos Panagiotakos, when supported by specialist assessment, genicular RF may be combined with pulsed radiofrequency (PRF) of the L4 dorsal root ganglion, under fluoroscopic guidance with contrast.

Selection requires assessment of the neuropathic component, symptom distribution and neurological findings, with selective tests when useful. Knee pain alone does not automatically identify L4 as the treatment target.

Ganglion PRF aims at neuromodulation, distinct from thermal denervation of peripheral branches. It does not involve implanting a permanent stimulator.

Albayrak and colleagues retrospectively assessed 39 patients with persistent pain after TKR, comparing TENS and exercise with the same programme plus ganglion PRF. Some pain and neuropathic outcomes favoured PRF, but the design and sample size limit conclusions. The study did not evaluate combining ganglion PRF with genicular nerve denervation.

Combined treatment is therefore an individualised option when there are indications for both procedures.

Albayrak et al., 2017.

Goals, risks and follow-up

Measurable goals are agreed before treatment: walking, stairs, sleep, pain on touch and medication use. Follow-up assesses pain, sensation and strength separately.

Peripheral RF risks include temporary pain, bruising, infection, sensory changes, burns and vascular or nerve injury. Ganglion procedures also require consideration of access near the nerve root, fluoroscopy and contrast. Anticoagulants and antiplatelet medicines are managed individually; do not stop them without medical advice.

When prompt assessment is needed

Fever, wound discharge, increasing redness or swelling, suddenly different pain or inability to bear weight require prompt contact with the treating team. A painful swollen calf needs rapid assessment; breathlessness or chest pain require emergency care.

Sources and further reading

• Wylde et al., 2018 — Chronic pain after total knee arthroplasty.
• Pain following total knee arthroplasty – a systematic approach.
• Towards an understanding of the painful total knee: what is the role of patient biology?
• Qudsi-Sinclair et al., 2017 — Randomised comparison of genicular RF and local anaesthetic/corticosteroid block after TKR.
• Froidefond et al., 2024 — Ultrasound-guided thermal radiofrequency ablation of the genicular nerves after total knee replacement.
• Shaukhin et al., 2026 — Systematic review of genicular nerve radiofrequency after TKR.
• Albayrak et al., 2017 — Dorsal root ganglion PRF added to TENS and exercise for persistent pain after TKR.

What is the aim of the pathway?

Reducing pain means seeking a meaningful improvement in daily life: walking more comfortably, managing stairs, sleeping better and participating in rehabilitation.

Treatment decisions consider expected benefits, risks and alternatives. Follow-up measures the outcome and reassesses any remaining components of pain.

A painful knee replacement deserves a diagnosis and a dedicated care pathway.