Knee Dislocation.
What is a knee dislocation?
"Knee dislocation" describes two distinct conditions that are frequently confused — patella dislocation and tibiofemoral dislocation — and the distinction matters enormously for management.
Patella dislocation — by far the more common presentation — occurs when the kneecap (patella) displaces laterally out of the trochlear groove at the front of the femur. It is a common sporting injury, particularly in adolescents and young adults, and while painful and distressing it is not typically limb-threatening. Most patella dislocations are managed conservatively with physiotherapy, though recurrence is common without adequate rehabilitation and some patients require surgical stabilisation.
Tibiofemoral dislocation — the true "knee dislocation" — occurs when the tibia and femur separate at the knee joint itself. This is a rare but serious injury, most commonly from high-energy trauma such as motor vehicle accidents, falls from height or high-speed sporting impacts. It is a surgical emergency because the popliteal artery — which passes directly behind the knee — is at significant risk of injury from tibiofemoral dislocation, and vascular compromise can lead to limb loss if not promptly identified and treated. Any suspected tibiofemoral dislocation requires immediate emergency medical assessment.
This page primarily addresses patella dislocation, which is the more common presentation seen in outpatient physiotherapy. For tibiofemoral dislocation, post-surgical rehabilitation following ligament reconstruction and vascular repair is the physiotherapy context, and management is tailored to the specific surgical procedures performed.
Patella dislocation — what happens
The patella normally sits within the trochlear groove and tracks centrally during knee flexion and extension. Lateral patella dislocation occurs when the kneecap is forced or slides out of this groove to the lateral side — typically from a pivoting movement, a direct blow to the medial knee, or both combined. The medial patellofemoral ligament (MPFL) — the primary passive restraint preventing lateral patella displacement — is torn in virtually all first-time dislocations and is the key structure requiring rehabilitation or surgical reconstruction.
At the moment of dislocation, the lateral femoral condyle and the medial patella are compressed against each other as the patella snaps back into position (which it often does spontaneously or with simple extension of the knee). This can produce osteochondral damage — injury to the articular cartilage and underlying bone — at these contact points, which is why imaging after a first patella dislocation is important.
Who gets patella dislocations?
Adolescents and young adults, particularly females, are most commonly affected — the biomechanical factors predisposing to patella instability include trochlear dysplasia (a shallow or abnormal trochlear groove), patella alta (a high-riding patella), tibial tubercle-trochlear groove distance outside normal range, and valgus knee alignment. People with joint hypermobility and EDS are at elevated risk of patella instability due to the generalised ligamentous laxity affecting the MPFL and surrounding structures.
What are the symptoms?
Acute patella dislocation produces immediate pain, a sensation of the kneecap popping out, and rapid swelling from haemarthrosis (bleeding into the joint). The knee is typically held in partial flexion and the patient is unable to straighten it comfortably until the patella is reduced. Once reduced — either spontaneously or by a clinician — pain and swelling persist for several weeks. Ongoing symptoms of patella instability include a feeling that the kneecap might slip again with pivoting or sudden direction changes, apprehension with knee bending, and medial knee pain from the torn MPFL.
How is it diagnosed?
A knee dislocation is usually diagnosed through a combination of physical examination, imaging tests such as X-rays or MRI, and evaluation of symptoms including swelling, bruising and instability in the knee joint.
X-ray confirms the reduction and identifies associated bony injuries including osteochondral fractures. MRI assesses the MPFL, trochlear morphology, osteochondral injury extent and the integrity of the other ligaments. The trochlear dysplasia classification and tibial tubercle-trochlear groove distance measurement guide the surgical decision-making if recurrent instability is a concern.
Surgery versus conservative management
First-time patella dislocation in patients without significant osteochondral injury or underlying anatomical risk factors is managed conservatively with physiotherapy in the vast majority of cases. The MPFL heals without surgical repair in most first-time dislocators, and appropriate physiotherapy produces good outcomes.
Recurrent patella dislocation — a second or subsequent episode — is increasingly managed surgically, particularly in young active patients. MPFL reconstruction — using a tendon graft to reconstruct the torn ligament — is the most common procedure, sometimes combined with tibial tubercle transfer to correct anatomical risk factors. Post-surgical physiotherapy follows a structured protocol similar to that for knee ligament reconstruction.
How can physiotherapy help?
Physiotherapy plays a crucial role in the rehabilitation of knee dislocations, developing a personalised treatment plan that includes exercises to strengthen the muscles around the knee joint, teaching safe performance of daily living activities, and using modalities including manual therapy and joint mobilisation to improve mobility and flexibility.
The physiotherapy approach for patella dislocation addresses both the acute injury and the underlying risk factors that predispose to recurrence.
In the first two to four weeks, swelling management, gentle range-of-motion restoration and quadriceps activation are the priorities. The knee is typically supported in a brace holding the patella in the correct position during early healing. VMO strengthening — using real time ultrasound to ensure the correct muscle is activating — begins as soon as comfortable.
From four to twelve weeks, progressive VMO and quadriceps strengthening, hip abductor and external rotator strengthening to reduce dynamic valgus during functional movement, and proprioception and balance training are the core rehabilitation targets. The hip musculature's role in controlling patella tracking is critical and frequently undertreated.
From three to six months, sport-specific rehabilitation including agility training, cutting and pivoting drills, and return to sport testing complete the rehabilitation. Patella taping and bracing can provide symptom control and proprioceptive benefit during rehabilitation and return to sport.
Clinical Pilates provides a controlled environment for progressive lower limb strengthening with precise load control during rehabilitation phases when full sport training is not yet appropriate.
Our physiotherapists Eliane Machado and Emma Cameron both have experience in knee conditions and patella instability rehabilitation and are members of the Australian Physiotherapy Association. Eliane's doctoral research in knee biomechanics is directly relevant to the patella tracking and lower limb mechanics assessment central to patella dislocation rehabilitation.
To book or find out more, call us on 07 3706 3407 or book online below. We see patients from across Brisbane's southside including Tarragindi, Coorparoo, Holland Park, Greenslopes and Mt Gravatt.
"Knee dislocation" describes two distinct conditions that are frequently confused — patella dislocation and tibiofemoral dislocation — and the distinction matters enormously for management.
Patella dislocation — by far the more common presentation — occurs when the kneecap (patella) displaces laterally out of the trochlear groove at the front of the femur. It is a common sporting injury, particularly in adolescents and young adults, and while painful and distressing it is not typically limb-threatening. Most patella dislocations are managed conservatively with physiotherapy, though recurrence is common without adequate rehabilitation and some patients require surgical stabilisation.
Tibiofemoral dislocation — the true "knee dislocation" — occurs when the tibia and femur separate at the knee joint itself. This is a rare but serious injury, most commonly from high-energy trauma such as motor vehicle accidents, falls from height or high-speed sporting impacts. It is a surgical emergency because the popliteal artery — which passes directly behind the knee — is at significant risk of injury from tibiofemoral dislocation, and vascular compromise can lead to limb loss if not promptly identified and treated. Any suspected tibiofemoral dislocation requires immediate emergency medical assessment.
This page primarily addresses patella dislocation, which is the more common presentation seen in outpatient physiotherapy. For tibiofemoral dislocation, post-surgical rehabilitation following ligament reconstruction and vascular repair is the physiotherapy context, and management is tailored to the specific surgical procedures performed.
Patella dislocation — what happens
The patella normally sits within the trochlear groove and tracks centrally during knee flexion and extension. Lateral patella dislocation occurs when the kneecap is forced or slides out of this groove to the lateral side — typically from a pivoting movement, a direct blow to the medial knee, or both combined. The medial patellofemoral ligament (MPFL) — the primary passive restraint preventing lateral patella displacement — is torn in virtually all first-time dislocations and is the key structure requiring rehabilitation or surgical reconstruction.
At the moment of dislocation, the lateral femoral condyle and the medial patella are compressed against each other as the patella snaps back into position (which it often does spontaneously or with simple extension of the knee). This can produce osteochondral damage — injury to the articular cartilage and underlying bone — at these contact points, which is why imaging after a first patella dislocation is important.
Who gets patella dislocations?
Adolescents and young adults, particularly females, are most commonly affected — the biomechanical factors predisposing to patella instability include trochlear dysplasia (a shallow or abnormal trochlear groove), patella alta (a high-riding patella), tibial tubercle-trochlear groove distance outside normal range, and valgus knee alignment. People with joint hypermobility and EDS are at elevated risk of patella instability due to the generalised ligamentous laxity affecting the MPFL and surrounding structures.
What are the symptoms?
Acute patella dislocation produces immediate pain, a sensation of the kneecap popping out, and rapid swelling from haemarthrosis (bleeding into the joint). The knee is typically held in partial flexion and the patient is unable to straighten it comfortably until the patella is reduced. Once reduced — either spontaneously or by a clinician — pain and swelling persist for several weeks. Ongoing symptoms of patella instability include a feeling that the kneecap might slip again with pivoting or sudden direction changes, apprehension with knee bending, and medial knee pain from the torn MPFL.
How is it diagnosed?
A knee dislocation is usually diagnosed through a combination of physical examination, imaging tests such as X-rays or MRI, and evaluation of symptoms including swelling, bruising and instability in the knee joint.
X-ray confirms the reduction and identifies associated bony injuries including osteochondral fractures. MRI assesses the MPFL, trochlear morphology, osteochondral injury extent and the integrity of the other ligaments. The trochlear dysplasia classification and tibial tubercle-trochlear groove distance measurement guide the surgical decision-making if recurrent instability is a concern.
Surgery versus conservative management
First-time patella dislocation in patients without significant osteochondral injury or underlying anatomical risk factors is managed conservatively with physiotherapy in the vast majority of cases. The MPFL heals without surgical repair in most first-time dislocators, and appropriate physiotherapy produces good outcomes.
Recurrent patella dislocation — a second or subsequent episode — is increasingly managed surgically, particularly in young active patients. MPFL reconstruction — using a tendon graft to reconstruct the torn ligament — is the most common procedure, sometimes combined with tibial tubercle transfer to correct anatomical risk factors. Post-surgical physiotherapy follows a structured protocol similar to that for knee ligament reconstruction.
How can physiotherapy help?
Physiotherapy plays a crucial role in the rehabilitation of knee dislocations, developing a personalised treatment plan that includes exercises to strengthen the muscles around the knee joint, teaching safe performance of daily living activities, and using modalities including manual therapy and joint mobilisation to improve mobility and flexibility.
The physiotherapy approach for patella dislocation addresses both the acute injury and the underlying risk factors that predispose to recurrence.
In the first two to four weeks, swelling management, gentle range-of-motion restoration and quadriceps activation are the priorities. The knee is typically supported in a brace holding the patella in the correct position during early healing. VMO strengthening — using real time ultrasound to ensure the correct muscle is activating — begins as soon as comfortable.
From four to twelve weeks, progressive VMO and quadriceps strengthening, hip abductor and external rotator strengthening to reduce dynamic valgus during functional movement, and proprioception and balance training are the core rehabilitation targets. The hip musculature's role in controlling patella tracking is critical and frequently undertreated.
From three to six months, sport-specific rehabilitation including agility training, cutting and pivoting drills, and return to sport testing complete the rehabilitation. Patella taping and bracing can provide symptom control and proprioceptive benefit during rehabilitation and return to sport.
Clinical Pilates provides a controlled environment for progressive lower limb strengthening with precise load control during rehabilitation phases when full sport training is not yet appropriate.
Our physiotherapists Eliane Machado and Emma Cameron both have experience in knee conditions and patella instability rehabilitation and are members of the Australian Physiotherapy Association. Eliane's doctoral research in knee biomechanics is directly relevant to the patella tracking and lower limb mechanics assessment central to patella dislocation rehabilitation.
To book or find out more, call us on 07 3706 3407 or book online below. We see patients from across Brisbane's southside including Tarragindi, Coorparoo, Holland Park, Greenslopes and Mt Gravatt.
