Patellar Instability (Unstable Kneecap) | The Back Pain Doctor Brisbane

Patellar Instability (Unstable Kneecap) — assessment and management in Brisbane

Patellar instability is when the kneecap slips partly or fully out of its groove. It can cause dislocation, a feeling the knee will give way, and pain at the front of the knee.

Patellar instability is when the kneecap slips partly (subluxation) or completely (dislocation) out of the groove it normally glides in. It can follow a single twisting injury or a direct blow, and in some people it recurs, producing pain, swelling and a persistent sense that the knee is about to give way. Structural factors — a shallow groove, ligament (MPFL) damage, alignment and rotation of the leg, and where the patellar tendon attaches — all influence the risk.

Assessment covers how the episode happened, how the kneecap tracks, and whether alignment or muscle weakness predisposes to further dislocation. A dislocated kneecap that will not reduce, or a locked knee that cannot bear weight, needs same-day assessment. Imaging with X-ray, and often MRI, is used to look for loose fragments and to assess the ligaments and anatomy of the knee.

First-line care after a first dislocation is usually non-surgical — reduction if needed, a period of bracing, then a structured physiotherapy program to strengthen the quadriceps and hip and improve kneecap control, with a graded return to activity. Most first dislocations do well this way. Recurrent instability, high-risk first dislocations, or a severely maltracking kneecap are referred for an orthopaedic opinion, where soft-tissue reconstruction or bony realignment may be considered.

Common symptoms

The kneecap slipping, partly dislocating or fully dislocating
A feeling the kneecap is about to give way (apprehension)
Pain and swelling at the front of the knee after an episode
Reluctance to twist, pivot or bend the knee under load

Evidence-informed treatment summary

How our treatment options may fit for Patellar Instability (Unstable Kneecap)

The options below include the treatments offered at The Back Pain Doctor. Listing a treatment does not mean it is recommended for this condition. The evidence, likely benefit and role of each option are considered against the diagnosis, examination findings, imaging where appropriate, patient goals, risks, cost and alternatives.

Foundation

Diagnosis, education and progressive rehabilitation

This is the starting point for most musculoskeletal conditions.

The priority is to identify the likely pain generator, explain the condition clearly, modify aggravating load and build a realistic plan to restore strength, movement and confidence.

Condition-dependent

Focused / radial shockwave therapy

Evidence is condition-specific; it is not a universal pain treatment.

Shockwave is best framed as an adjunct where the diagnosis fits. It is generally more established for selected tendon and plantar heel pain presentations than for many joint or nerve conditions.

Selected cases

Platelet-rich plasma (PRP)

Evidence varies substantially by condition, tissue and preparation method.

PRP may be discussed in selected tendon or joint presentations. It should not be presented as a guaranteed regenerative treatment, and uncertainty, cost and alternatives should be discussed.

Symptom relief

Image-guided corticosteroid / local anaesthetic injection

Best used for specific inflammatory or irritable pain generators, usually for short-term relief.

An injection may help when a joint, bursa, tendon sheath or other defined structure is driving symptoms. It is not a cure and needs to be weighed against risks, recurrence and the need for rehabilitation.

Emerging adjunct

EMTT / magnetotransduction

Clinical evidence is still developing and guideline support is limited.

EMTT may be discussed as an adjunct in selected presentations, but should be presented with clear uncertainty and never as a replacement for diagnosis, load management or rehabilitation.

Selected cases

Prolotherapy

Evidence is condition-specific and generally less established than exercise-based care.

Prolotherapy may be considered in carefully selected chronic ligament, tendon or joint-related pain presentations, but it is not a first-line treatment.

Pain modulator

Trigger point / myofascial treatment

Most relevant when focal myofascial pain is a clear contributor.

Trigger point treatment may reduce pain from focal muscle spasm or myofascial tenderness. It should be paired with movement restoration, strength work and recurrence prevention.

Nerve-specific

Nerve-focused treatment / hydrodissection

Relevant only when the history and examination support nerve irritation or entrapment.

Nerve-focused treatment may be discussed when there is a plausible peripheral nerve pain generator. Progressive weakness, major neurological deficit or red flags require a different pathway.

This is general information only. Suitability is assessed individually. Treatments with limited or condition-dependent evidence may still be discussed, but only with clear explanation of uncertainty, expected benefit, risks, cost and alternatives. Red flags, progressive neurological symptoms or suspected serious pathology require a different pathway.

Frequently asked questions

How is patellar instability diagnosed?

Assessment is clinical to start with — how the injury happened, how the kneecap tracks and moves, and whether the alignment or thigh muscles suggest a tendency to dislocate. X-rays are usually taken, and an MRI may be arranged to check for loose fragments of bone or cartilage and to assess the ligaments. A CT scan is sometimes used to evaluate bony alignment.

What does treatment involve?

A fully dislocated kneecap first needs to be returned to its groove. For a first dislocation, care is usually non-surgical — a period of bracing followed by a physiotherapy program to strengthen the thigh and hip and restore control, with a gradual return to sport over roughly one to three months. Surgery is generally reserved for recurrent instability or high-risk cases.

When should a dislocated kneecap be seen urgently?

A kneecap that stays dislocated and will not go back into place, a locked knee that cannot bear weight, or a knee that swells rapidly after the injury should be assessed the same day. A first dislocation can be associated with a loose fragment of bone or cartilage that needs to be looked for.

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Your assessment focuses on understanding the likely source of your pain and the most appropriate non-surgical options for your diagnosis, with the aim of reducing pain and improving function.

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