Knee Pain

Patella Dislocations


What is a Patella Dislocation?

Patella (kneecap) dislocations are quite common and can be very disconcerting to the sufferer. The Patella sits in a groove (Trochlea) in the Femur and usually glides up and down in this Femoral Trochlea during movement. Dislocation occurs when the Patella is forced out of this groove, usually laterally, causing pain, swelling and temporary deformity of the knee joint. Quite often the Patella relocates spontaneously when the patient moves the leg but if this does not happen then it must be relocated by a suitably qualified medical professional. 1. 4. 8. 9.

Perhaps even more common is a Patella Subluxation, a partial dislocation that relocates before the point of full dislocation. There is still pain and swelling because of the bone on bone friction and in either a subluxation or dislocation the patient will suffer apprehension and instability. 3. 5. 7.


(UMMC, 2008)




What causes Patella Dislocations?

There are a number of predisposing factors that may lead to Patella Dislocation. The shape of the Trochlea, the size and shape of the Patella, inherent joint laxity either ligamentous or muscular, stage of maturation, muscle imbalance and poor proprioception. 2. 6.

Patella dislocations occur more often in younger athletes due perhaps to some of the aforementioned factors but also perhaps because of the vigorous activities undertaken. Dislocations occur either extrinsically (direct contact with an external force) or intrinsically (from forces generated within) usually when landing with a twist or from a twist such as in gymnastics, rugby or football. 2. 11. 12.

What are the signs and symptoms?

A Patella dislocation that does not relocate spontaneously is obvious. The Patella sits to one side of the knee; usually the lateral side, and the patient will be unable to move the knee at first. There will be pain and swelling follows fairly quickly afterwards. The sufferer will have felt a “giving way” of the knee at the point of impact or landing and apprehension will limit movement. Usually Patella dislocations incur other injuries such as Patella Ligament damage; bone-on-bone friction, which can cause fragments of bone to break off; Capsular tears and other soft tissue damage. 5. 9. 11.

Patella subluxations have similar symptoms as dislocations except that the Patella relocates prior to full dislocation. Apart therefore from the deformity of a dislocation the symptoms are pretty much the same. 1. 3. 12.


Dislocated Knee

 (Fight times, 2003)


What else could it be?

There are other conditions that can mimic a subluxation such as a Meniscus tear; Jumpers knee; Patello-Femoral Pain Syndrome; bone lesions and a host of other conditions. 4. 7. 9. 12. The deformity of a Patella Dislocation however is pretty obvious.

What can be done about it?

In the case of a Patella Dislocation it is important to go to A&E so that the Patella can be safely relocated but also to check for other injuries such as bone damage. Quite often the dislocation hides the fact that other injuries have occurred.

If the Patella has spontaneously relocated then it may still be wise to have the knee checked at A&E for similar reasons as above. Quite often however the sufferer has not fully realised what has happened and often goes home to nurse an increasingly swollen knee.

As with most injuries control of swelling is important in order to begin the rehabilitation process as soon as possible. Therefore the PRICE regime (Protect; Rest; Ice; Compression: Elevation) should be followed. 6. 8. Be careful with the application of ice regime as too long an application of ice can increase swelling! Similarly, always place a barrier between the ice and the patients skin and try to use melting ice (not straight from the freezer) to prevent ice burns. 5. 7.

Static quadriceps exercises should be performed as soon as the patient feels able to as this will help remove swelling and begin restoring muscle function. Movement and strength will gradually be restored over time. 4. 9. 11. 12.

Giving a time frame for these processes is difficult due to the vastly differing severity of this condition.

In order to rehabilitate faster and to minimise the chances of re-injury it is advisable to seek the services of a Graduate Sports Therapist or a Physiotherapist who has undergone extensive training in sports injury management.

The Authors View

Patella dislocations can be very traumatic as they almost totally debilitate the athlete for a period of time. The pain and swelling take time to subside but perhaps the most debilitating aspect is the apprehension at the thought of it going again. Careful rehabilitation with graded return to activity is vital not only for the injury to repair but to ultimately nurse the athlete back to competition level from a psychological perspective. A Graduate Sports Therapist or Physiotherapist with appropriate sports specific qualifications will be able to help in this rehabilitation process.


Reference List:

  1. Kepler, C. K., Bogner, E. A., Hammoud, S., Malcomson, G., Potter, H. G. & Green, D. W. (2011). Zone of injury of the medial patellofemoral ligament after acute patellar dislocation in children and adolescents. The American Journal of Sports Medicine. 39(7), 1444-1449.
  2. Camp. C. L., Krych, A. J., Dahm, D. L., Levy, B. A. & Stuart, M. J. (2010). Medial patellofemoral ligament repair for recurrent patellar dislocation.  The American Journal of Sports Medicine. 38(11), 2248-2254.
  3.  Shah, J. N., Howard, J. S., Flanigan, D. C., Brophy, R. H., Carey, J. L. & Lattermann, C. (2012). A systematic review of complications and failures associated with medial patellofemoral ligament reconstruction for recurrent patellar dislocation. The American Journal of Sports Medicine. 40(8), 1916-1923.
  4. Earhart, C., Patel, D. B., White, E. A., Gottsegen, C. J., Forrester, D. M. & Matcuk, G. R. (2013). Transient lateral patellar dislocation: a review of imaging findings, patellofemoral anatomy, and treatment options. Emergency radiology. 20(1), 11-23.
  5. Hsiao, M., Owens, B. D., Burks, R., Sturdivant, R. X. & Cameron, K. L. (2010). Incidence of acute traumatic patellar dislocation among active-duty united states military service members. The American Journal of Sports Medicine. 38(10), 1997-2004.
  6. Fisher, B., Nyland, J., Brand, E. & Curtin, B. (2010). Medial patellofemoral ligament reconstruction for recurrent patellar dislocation: A systematic review including rehabilitation and return-to-sports efficacy. The Journal of Arthroscopic and related surgery. 26(10), 1384-1394.
  7. Bitar, A. C., Demange, M. K., D’Elia, C. O. & Camanho, G. L. (2011). Traumatic patellar dislocations nonoperative treatment compared with MPFL reconstruction using patellar tendon. The American Journal of Sports Medicine. 40(1), 114-122.
  8. Smith, T. O., Song, F., Donnel, S. T. & Hing, C, B. (2011). Operative versus non-operative management of patellar dislocation. A meta-analysis. Knee Surgery, Sports Traumatology, Arthroscopy. 19(6), 988-998.
  9. Seeley, M., Bowman, K. F., Walsh, C., Sabb, B. J. & Vanderhave, K. L. (2012). Magnetic resonance imaging of acute patellar dislocation in children: Patterns of injury and risk factors for recurrence. Journal of Paediatrics Orthopaedics. 32(2), 145-155.
  10.  Haas, J. P., Collins, M. S. & Stuart, M. J. (2012). The “silver sign”: a specific radiographic sign of acute lateral patellar dislocation. Skeletal Radiology. 41(5), 595-601.
  11. Alves, C., Oliveira, C., Murnaghan, M., Narayanan, U. & Wright, J. (2012). Operative compared with non-operative treatment for primary patellar dislocation: A systematic review and meta-analysis.
  12. Noda, M., Saegusa, Y., Kashiwagi, N. & Seto, Y. (2011). Surgical Treatment for permanent dislocation of the patella in adults. Journal of Orthopaedics.  34(12), 948-951.



Keith Waldon - MSc. Cert. Ed. Postgrad. Dip. Phys. MSST. MCSP. Vice-Chairman Society of Sports Therapists Is the owner and director of Up and Running Portsmouth, a sports therapy practice operating out of the Nuffield Health club Portsmouth. Keith has had over forty years experience in professional sport as a player, coach, teacher, physiotherapist & sports therapist. On two occasions he has attended teams in the F.A. Cup Final with Tottenham Hotspur F.C. where he spent ten successful years. He then spent five years at Portsmouth Football Club as the Assistant Manager and Physiotherapist. In both capacities he has dealt with several of the country's top footballers. He has lectured at Portsmouth University on the Treatment of Injury and is very experienced in many aspects of the sporting spectrum. Keith has owned his own chain of sports injury clinics for several years. It was this experience which prompted him to co-write and produce a degree course in the treatment and rehabilitation of sports injuries. The BSc (Hons) Sports Therapy is now available in several universities throughout Britain and Keith is at the forefront of this initiative.