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 Table of Contents  
CASE REPORT
Year : 2020  |  Volume : 12  |  Issue : 2  |  Page : 156-158

Irreducible Vertical Dislocation of Patella Incarcerated into a Lateral Condyle Femur Fracture


Department of Orthopedics, Hindu Rao Hospital and NDMC Medical College, Delhi, India

Date of Submission01-Jan-2020
Date of Acceptance14-Apr-2020
Date of Web Publication28-Dec-2020

Correspondence Address:
Dr. Rejo Varghese Jacob
Department of Orthopedics, Hindu Rao Hospital and NDMC Medical College, Delhi
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jotr.jotr_1_20

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  Abstract 


Rotational dislocations of patella around the horizontal and vertical axis are rare injuries. Unlike lateral patellar dislocations, which are easily reducible, closed reduction in vertical fractures is usually not possible due to increased tension within the quadriceps tendon. We present a case report of an 18-year-old male who presented with swelling and pain over the right knee following a road traffic accident. The clinical and radiological assessment showed a fracture of the lateral femoral condyle with dislocation of the patella, which was irreducible by closed methods. Computed tomography showed a lateral condyle femur fracture with concomitant dislocation of the patella rotated on its vertical axis and incarcerated into the fracture site. Closed reduction in these kinds of injuries is difficult, and open reduction of the patella and internal fixation of the fracture is recommended.

Keywords: Medial parapatellar approach, open reduction, vertical dislocation


How to cite this article:
Jain SK, Jacob RV, Kumar S, Parasurampuriya VK. Irreducible Vertical Dislocation of Patella Incarcerated into a Lateral Condyle Femur Fracture. J Orthop Traumatol Rehabil 2020;12:156-8

How to cite this URL:
Jain SK, Jacob RV, Kumar S, Parasurampuriya VK. Irreducible Vertical Dislocation of Patella Incarcerated into a Lateral Condyle Femur Fracture. J Orthop Traumatol Rehabil [serial online] 2020 [cited 2021 Jan 21];12:156-8. Available from: https://www.jotr.in/text.asp?2020/12/2/156/305077




  Introduction Top


Dislocation of the patella usually occurs on the lateral side while a more rare type of intra-articular dislocation involves rotation of the patella around its horizontal or vertical axis.[1] The vertical axis type dislocations (when the articular surface of the patella faces medially or laterally) can be difficult to reduce by closed methods and usually have associated osteochondral injuries, lateral condyle fractures, or Hoffa's fracture.[2],[3],[4],[5] We came across a case of the lateral condyle femur fracture with vertically rotated dislocated patella incarcerated between the fracture fragments, which was managed by open reduction.


  Case Report Top


A 18-year-old male came to the casualty with pain and swelling over the right knee following a road traffic accident. He was a pillion rider on a motorcycle that hit a car. The patient fell off the motorcycle with a direct impact of the medial side of the knee on the road. Clinical examination of the knee showed a prominence over the lateral aspect of the knee joint with tenderness over the lateral condyle of the femur and knee was locked at 20° flexions. The limb was splinted and sent for radiographs. Plain radiograph of the right knee antero-posterior and lateral views showed a Hoffa fractured femur with a laterally dislocated patella [Figure 1]. Computerized tomography was done to confirm the configuration of fracture fragments and to rule out any other bony injury, which showed a fracture of the lateral condyle in the sagittal plane with some posterior comminution and vertically dislocated patella, incarcerated between the fracture fragments, with the articular surface of the patella facing laterally [Figure 2],[Figure 3],[Figure 4]. Emergency surgery was carried out through midline skin incision, which was extended slightly laterally in the proximal part. Medial patellafemoral ligament, retinaculum, and quadriceps tendon were found to be intact, and the patella was dislocated, rotated, and incarcerated in the fracture site. Medial parapatellar arthrotomy was done, and the fracture site was distracted in full extension. The patella was derotated and repositioned on the trochlear sulcus. Lateral condyle fracture was reduced and fixed with two partially threaded 7mm cancellous screws and medial plication was done [Figure 5]. The patella was tracked in flexion and extension and was found normal. The limb was immobilized in an above knee slab.
Figure 1: Preoperative X-ray of the right knee anteroposterior and lateral view immediately after injury showing distal femur fracture and dislocated patella

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Figure 2: Preoperative coronal computed tomography image of the right knee taken 1 h after admission showing dislocated and rotated patella

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Figure 3: Preoperative axial computed tomography image of the right knee taken 1 h after admission showing dislocated, rotated patella incarcerated into the fracture fragment

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Figure 4: Preoperative three-dimensional reconstruction computed tomography image of the right knee taken 1 h after admission

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Figure 5: Postoperative X-ray of the right knee anteroposterior and lateral view taken immediately after surgery

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The patient was assessed postoperatively and the slab was removed on the 2nd postoperative day. Static quadriceps exercise was started and the limb was kept nonweight-bearing. The patient was started on active knee flexion and extension exercises at 4 weeks and full weight bearing began at 8 weeks. Fracture showed radiological union at 12 weeks and the patient returned to his routine work by 5 months [Figure 6]. He regained full extension and flexion up to 120°.
Figure 6: Postoperative X-ray of the right knee anteroposterior and lateral view taken 6 months after surgery

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  Discussion Top


The first description of a vertically rotated and dislocated patella was given by Cooper in 1844.[6] However a dislocated, rotated, and incarcerated patella into a fracture is extremely rare, with very few cases reported in the literature.[1]

The stability of the patella in the trochlear groove is primarily decided by bony constraints and ligamentous tethers. Together, these elements determine the limits of passive patellar displacement and a risk factor for acute patellar dislocation.

The mechanism of injury is unclear and not reported in literature. A direct impact or blow to the medial side of the knee in extension and valgus causes the quadriceps to become taut and dislocating and rotating the patella.[7],[8] At the same time, an axial load on a flexed knee drives the proximal tibia onto the femoral condyle resulting in a shearing force and a fracture of femoral condyles.[9] The position of the knee is controversial. According to us, a direct blow to a semi flexed knee with an axial and valgus force may lead to such an injury pattern.


  Conclusion Top


This extremely uncommon injury is difficult to diagnose and treat. A high index of suspicion following the physical examination and proper observation of radiographs and Computerized tomography is essential to diagnose the problem. The closed reduction will be futile in such cases and may lead to further damage to soft tissues and cartilage.[10] Immediate open reduction of the patella and internal fixation of the fracture followed by repair of soft-tissue structures is required for the good results.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Frangakis EK. Intra-articular dislocation of the patella. A case report. J Bone Joint Surg Am 1974;56:423-4.  Back to cited text no. 1
    
2.
Vaishya R, Singh AP, Dar IT, Singh AP, Mittal V. Hoffa fracture with ipsilateral patellar dislocation resulting from household trauma. Can J Surg 2009;52:E3-4.  Back to cited text no. 2
    
3.
Soraganvi PC, Gowda BN, Rajagopalakrishnan R, Gavaskar AS. Irreducible, incarcerated vertical dislocation of patella into a Hoffa fracture. Indian J Orthop 2014;48:525-8.  Back to cited text no. 3
[PUBMED]  [Full text]  
4.
Nomura E, Inoue M, Kurimura M. Chondral and osteochondral injuries associated with acute patellar dislocation. Arthroscopy 2003;19:717-21.  Back to cited text no. 4
    
5.
Gidden DJ, Bell KM. An unusual case of irreducible intra-articular patellar dislocation with vertical axis rotation. Injury 1995;26:643-4.  Back to cited text no. 5
    
6.
Cooper A. A Treatise on Dislocations and Fractures of Joints. Philadelphia: Lea and Blanchard; 1844. p. 178.  Back to cited text no. 6
    
7.
Corso SJ, Thal R, Forman D. Locked patellar dislocation with vertical axis rotation. A case report. Clin Orthop Relat Res 1992;279:190-3.  Back to cited text no. 7
    
8.
Shetty S, Ramesh B, Gul A, Madhusudan TR, Altayeb T. Vertical dislocation of the patella: Report of 2 cases. Orthopedics 2009;32:768-70.  Back to cited text no. 8
    
9.
Lewis SL, Pozo JL, Muirhead-Allwood WF. Coronal fractures of the lateral femoral condyle. J Bone Joint Surg Br 1989;71:118-20.  Back to cited text no. 9
    
10.
ElMaraghy AW, Berry GK, Kreder HJ. Irreducible lateral patellar dislocation with vertical axis rotation: Case report and review of the literature. J Trauma 2002;53:131-2.  Back to cited text no. 10
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]



 

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Case Report
Discussion
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