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Recurrent inferior patellar dislocation in an osteo-arthritic knee
The Knee 11 (2004) 141–142
Case report
Recurrent inferior patellar dislocation in an osteo-arthritic knee Mujahid Ali Syed*, Palanisamy Ramesh Broomfield Hospital, Chelmsford, Essex CM1 7ET, UK Received 1 May 2003; received in revised form 24 June 2003; accepted 14 August 2003
Abstract A case of inferior dislocation of the patella in an 80-year-old woman with an osteo-arthritic knee is presented. This is a rare injury in the degenerate knee and the first case in which recurrence, the need for operative reduction and intra-articular damage has been demonstrated. 䊚 2003 Elsevier Science B.V. All rights reserved. Keywords: Patella; Inferior Dislocation; Degenerate knee; Open reduction; Intra-articular damage
1. Introduction Inferior patellar dislocation in a degenerate knee is rare. In the case outlined, the need for operative intervention to prevent its recurrence is described. 2. Case report An 80-year-old fit and independent female presented to the accident and emergency department with a painful and deformed left knee after falling on a level ground whilst shopping. An X-ray done showed an inferior dislocation of the patella with the superior pole of the patella hinged in the inter-condylar notch of the femoral condyles (Fig. 1). This was treated by closed reduction under sedation in the accident and emergency department. The patient was sent home with a knee splint and was reviewed in the clinic after 6 days when the splint was removed and active mobilisation encouraged. Two days later her patella re-dislocated inferiorly when she flexed her knee in bed. Attempted reduction under sedation in the accident and emergency department failed. She was admitted and an attempt to reduce the dislocation under general anaesthetic was made. The patella reduced initially after manipulation but was *Corresponding author. Tel.: q44-797-739-8224. E-mail address: [email protected] (M.A. Syed).
found to re-dislocate on knee flexion beyond 100 degrees. An open reduction was performed through a medial parapatellar approach. Osteophytes on the superior pole were trapped in the inter-condylar notch of the femur. The Quadriceps and Patellar tendons were intact. The articular cartilage was eroded on the medial side of the lateral femoral condyle by the impaction of the osteophytes (Fig. 2). The osteophytes were trimmed and the patella relocated satisfactorily. The patient made an uneventful recovery and is currently mobilising independently. 3. Discussion Acute dislocation of the patella is well documented. Various types of dislocations have been described which include lateral, medial, superior and intra-articular, of which lateral is the most common w1x. Intra-articular dislocations can be vertical or horizontal depending on the axis of rotation of the patella w2x. The inferior dislocation described here can be considered as a horizontal type of intra-articular dislocation as the articular surface of the patella was found to be facing inferiorly. Bankes and Eastwood w3x classified inferior patellar dislocations into two types. The more common type 1 injuries are usually present in adolescents and are caused by direct violence on the patella w2,4x. Detachment of the quadriceps tendon from the superior pole of the
0968-0160/04/$ - see front matter 䊚 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S0968-0160Ž03.00112-1
142
M.A. Syed, P. Ramesh / The Knee 11 (2004) 141–142
patella causes osteophytes on the superior patellar pole to entrap in the inter-condylar notch of the femur leading to inferior dislocation. Previously reported cases were treated with simple manipulation with no evidence of structural damage to the knee or the extensor mechanism. The case presented here is unique because it highlights the need for possible operative reduction of the patella and excision of the superior osteophytes to prevent recurrence. There is also a potentially significant danger of intra-articular damage to the femoral condyle by the superior pole osteophyte. 4. Conclusion Inferior dislocation of the patella in the degenerate knee though rare, is well documented. This injury is not entirely benign as previously reported w3x. The need for operative reduction and the possibility of damage to the articular surface of the femur should be kept in mind while treating these injuries. References
Fig. 1. X-Ray demonstrating inferior dislocation of the patella.
patella may accompany these injuries w3,4x. Treatment is either open or closed reduction with limb immobilisation for 3–4 weeks w2–4x. Type 2 injuries occur in degenerate knees and are very rare w1,3,5,6x. Twisting injury to the knee with or without direct impact to the
w1x Joshi RP. Inferior dislocation of the patella. Injury 1997;28:5 – 6. w2x Murakami Y. Intra-articular dislocation of the patella. A case report. Clin Orthop 1982;171:137 –139. w3x Bankes MJK, Eastwood DDM. Inferior dislocation of the patella in the degenerate knee. Injury 2002;33:528 –529. w4x Sarkar SD. Central dislocations of the patella. J Trauma 1981;21:409 –410. w5x McCarthy TA, Quinn B, Pegum GM. Inferior dislocation of the patella: an unusual cause of a locked knee. Ir J Med Sci 2001;170:209 –210. w6x Desai A, Allcock S, Hardy SK. Horizontal intra-articular dislocation of the patella in an 88-year-old woman. The Knee 1995;2:243 –244.
Fig. 2. Intra-operative picture demonstrating intra-articular damage to the lateral femoral condyle (arrow).
Case report
Recurrent inferior patellar dislocation in an osteo-arthritic knee Mujahid Ali Syed*, Palanisamy Ramesh Broomfield Hospital, Chelmsford, Essex CM1 7ET, UK Received 1 May 2003; received in revised form 24 June 2003; accepted 14 August 2003
Abstract A case of inferior dislocation of the patella in an 80-year-old woman with an osteo-arthritic knee is presented. This is a rare injury in the degenerate knee and the first case in which recurrence, the need for operative reduction and intra-articular damage has been demonstrated. 䊚 2003 Elsevier Science B.V. All rights reserved. Keywords: Patella; Inferior Dislocation; Degenerate knee; Open reduction; Intra-articular damage
1. Introduction Inferior patellar dislocation in a degenerate knee is rare. In the case outlined, the need for operative intervention to prevent its recurrence is described. 2. Case report An 80-year-old fit and independent female presented to the accident and emergency department with a painful and deformed left knee after falling on a level ground whilst shopping. An X-ray done showed an inferior dislocation of the patella with the superior pole of the patella hinged in the inter-condylar notch of the femoral condyles (Fig. 1). This was treated by closed reduction under sedation in the accident and emergency department. The patient was sent home with a knee splint and was reviewed in the clinic after 6 days when the splint was removed and active mobilisation encouraged. Two days later her patella re-dislocated inferiorly when she flexed her knee in bed. Attempted reduction under sedation in the accident and emergency department failed. She was admitted and an attempt to reduce the dislocation under general anaesthetic was made. The patella reduced initially after manipulation but was *Corresponding author. Tel.: q44-797-739-8224. E-mail address: [email protected] (M.A. Syed).
found to re-dislocate on knee flexion beyond 100 degrees. An open reduction was performed through a medial parapatellar approach. Osteophytes on the superior pole were trapped in the inter-condylar notch of the femur. The Quadriceps and Patellar tendons were intact. The articular cartilage was eroded on the medial side of the lateral femoral condyle by the impaction of the osteophytes (Fig. 2). The osteophytes were trimmed and the patella relocated satisfactorily. The patient made an uneventful recovery and is currently mobilising independently. 3. Discussion Acute dislocation of the patella is well documented. Various types of dislocations have been described which include lateral, medial, superior and intra-articular, of which lateral is the most common w1x. Intra-articular dislocations can be vertical or horizontal depending on the axis of rotation of the patella w2x. The inferior dislocation described here can be considered as a horizontal type of intra-articular dislocation as the articular surface of the patella was found to be facing inferiorly. Bankes and Eastwood w3x classified inferior patellar dislocations into two types. The more common type 1 injuries are usually present in adolescents and are caused by direct violence on the patella w2,4x. Detachment of the quadriceps tendon from the superior pole of the
0968-0160/04/$ - see front matter 䊚 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S0968-0160Ž03.00112-1
142
M.A. Syed, P. Ramesh / The Knee 11 (2004) 141–142
patella causes osteophytes on the superior patellar pole to entrap in the inter-condylar notch of the femur leading to inferior dislocation. Previously reported cases were treated with simple manipulation with no evidence of structural damage to the knee or the extensor mechanism. The case presented here is unique because it highlights the need for possible operative reduction of the patella and excision of the superior osteophytes to prevent recurrence. There is also a potentially significant danger of intra-articular damage to the femoral condyle by the superior pole osteophyte. 4. Conclusion Inferior dislocation of the patella in the degenerate knee though rare, is well documented. This injury is not entirely benign as previously reported w3x. The need for operative reduction and the possibility of damage to the articular surface of the femur should be kept in mind while treating these injuries. References
Fig. 1. X-Ray demonstrating inferior dislocation of the patella.
patella may accompany these injuries w3,4x. Treatment is either open or closed reduction with limb immobilisation for 3–4 weeks w2–4x. Type 2 injuries occur in degenerate knees and are very rare w1,3,5,6x. Twisting injury to the knee with or without direct impact to the
w1x Joshi RP. Inferior dislocation of the patella. Injury 1997;28:5 – 6. w2x Murakami Y. Intra-articular dislocation of the patella. A case report. Clin Orthop 1982;171:137 –139. w3x Bankes MJK, Eastwood DDM. Inferior dislocation of the patella in the degenerate knee. Injury 2002;33:528 –529. w4x Sarkar SD. Central dislocations of the patella. J Trauma 1981;21:409 –410. w5x McCarthy TA, Quinn B, Pegum GM. Inferior dislocation of the patella: an unusual cause of a locked knee. Ir J Med Sci 2001;170:209 –210. w6x Desai A, Allcock S, Hardy SK. Horizontal intra-articular dislocation of the patella in an 88-year-old woman. The Knee 1995;2:243 –244.
Fig. 2. Intra-operative picture demonstrating intra-articular damage to the lateral femoral condyle (arrow).