+ Departement of orthopaedic surgery, UH Hassan II of Fès, morocco
* Departement of orthopaedic surgery, Lucien Hussel hospital of Vienne, french

Address for Correspondence
Dr Elibrahimi Abdelhalim
Hôpital Alghasssani, CHU Hassan II, Fès, Marocco
Email: halimibrahimi@yahoo.fr

The lateral patellar dislocation with vertical rotation of 90° is rare. We describe a case of dislocation of the patella around its vertical axis following a direct traumatism on the medial edge of the patella. The closed reduction was carried out with success under general anaesthesia.
Keys words: patellar dislocation, vertical rotation of 90°.

J.Orthopaedics 2006;3(4)e21

Introduction:

The patellar dislocation is a relatively frequent lesion for the young subjects. However, the majority are extra-articular. Intra-articular dislocation is rare and can occurs around the horizontal or vertical axis of the patella. The side variety with a rotation of 90° around the vertical axis is exceptional. We report a traumatic case of patellar dislocation  with a rotation of 90° according to the vertical axis, with orthopedic reduction.

Observations  

Patient  M.T 8 years old, admitted  in the emergency service of the hospital Lucien Hussel of Vienne, for traumatism of the left knee following a fall of the staircases. He complained about sharp pain of the knee, with a functional impotence. The examination had objectified a flessum knee of 80°, with an obviously luxated patella, making covered under the skin, outwards (Figure 1 and 2). Palpation revealed that the articular facet of the patella looked in anterolateral with a tended and twisted patellar tendon. The examination did not find any  cutaneous injury or disorders vasculo-highly-strung person. Standard radiographs objectified a side dislocation of the kneecap with rotation around its axis of 90 degrees (Figure 3). The orthopedic reduction had been carried out under general anaesthesia, by extending the member with a pressure on the medial edge of the patella. The reduction was confirmed radiologically (figure 4). An immobilization by a splint foundation of concrete was maintained hang 4 week. The result is good with whole return of the function of the knee without after-effect and repetition.

Figure 1: images showing side patellar dislocation with vertical rotation of 90° and attitude of the knee in inflection.

Figure 2: Radiograph of the knee showing the side position of the patella with rotation of 90°.

Figure 3: Radiograph of control after the reduction of patellar dislocation

Discussion :

Intra articular dislocation of the patella is a rare pathology [1, 2]. It can occur around the axis centers horizontal or vertical patella. Dislocation with rotation of 90° according to the axis vertical of the kneecap was described the first time in 1844 by Cooper [3]. The exact mechanism is not clear, and several theories were proposed. The majority of the cases were reported among adolescent boys with 16 years an average age [4]. Reichell [5] suggested that the laxity of the ligaments at the teenagers explains the great mobility of the kneecap and thereafter the great risk of dislocation in this category of young age while similar lesions would cause a tendineus rupture in the adults. The traumatisms of high energy can cause other tendineus tear, ligamentar or osteo-chondral such as a depression of the patella in the femoral condyle [6], these tears define the long-term forecast. The sporting accidents are the most reported cause [7]. The mechanism in these cases seems to be a direct traumatism on the side or medial edge of the knee while this last is in extension with a contracted quadriceps. The majority of the authors recommended an open reduction like primary education process. Six similar cases were reported in the 15 last years and in four cases, the multiple closed reductions had not succeeded, driving with a bloody reduction [8, 9,10]. To reduce the risk of osteochondral lesions, many authors suggest a surgical reduction [11]. The course is often favorable with a good functional result [12].

Conclusion

The side variety of patellar dislocation with a rotation of 90° around the vertical axis is extremely rare. The preserving treatment can be tried each time the closed reduction is possible. The functional results are always satisfactory without after-effects.

Reference :

1. Kaufman I, Haberman E: vertical Intercondylar dislocation of the patella. Bull Hosp Joint Say 34: 222-225, 1973

2. Alioto RJ, Kates S: vertical Intra-articular dislocation of the patella: box irreducible carryforward of year patellar single dislocation and has surgical technical. J Trauma; 36: 282-284, 1994

3. Cooper A: With treatise one dislocations and joined fractures of the. Philadelphia: Lea and Febiger; 1844, p.178.

4. Nanda R, Yadav RS, Thakur Mr: Intra-articular dislocation of the patella. J Trauma 48:159 -160, 2000

5. Reichell P: Injuries and disease of the knee and leg. Surgeries of the Extremities, A System of Practical Surgery. London: Williams and Norgate, 1904

6. Gidden J, Bell KM: Irreducible year unusual box of intra-articular patellar dislocation with vertical axis rotation. Injury: 643- 644, 1995

7. Alasdair R, Corfield and James Stevenson. Vertical patellar dislocation: box carryforward European Journal of Emergency Medicine 11:170-171

8. Rollinson PD has: Vertical intercondylar dislocation of the patella. Injury: 281- 2, 1988

9. Hackl W, Benedetto KP, Fink C and al: Locked lateral patellar dislocation: has rare irreducible box of patellar dislocation requiring open reduction. Knee Surg Sports Traumatol Arthrosc 352-5, 1999

10. Scott C, Sherman MD, Alfred Yu. Patellar dislocation with vertical axis rotation The Newspaper of Emergency Medicine, pp. 219-220, 2004

11. ElMaraghy AW, Berry GK, Kreder HJ. Irreducible lateral patellar dislocation with vertical axis rotation: put carryforward and review of literature. J Trauma 53: 131-2, 2002

12. Gann N, Nalty T Vertical patellar dislocation: box carryforward has. J Orthopaed Sports Phys Ther  368- 370,1998

This is a peer reviewed paper 

Please cite as : A. Elibrahimi: Lateral Patellar Dislocation with Vertical Axis Rotation of 90°:

J.Orthopaedics 2006;3(4)e21

URL: http://www.jortho.org/2006/3/4/e21

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