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Confirmation of an intact patellar tendon in superior dislocation of the patella using magnetic resonance imaging
Injury, Int. J. Care Injured 32 (2001) 167– 169 www.elsevier.com/locate/injury
Case report
Confirmation of an intact patellar tendon in superior dislocation of the patella using magnetic resonance imaging A. Iorwerth a,*, R. Thomas b, D.J. Shewring a a
Department of Orthopaedics and Trauma, Uni6ersity Hospital of Wales, Heath Park, Cardiff, UK b Morriston Hospital, Morriston, Swansea, UK Accepted 15 August 2000
1. Case report A 72-year-old lady sustained a fall whilst decorating her Christmas tree. Immediately after this she developed pain in her right knee and was unable to bear weight on that leg. The patient denied any previous injury to the knee or any symptoms related to it. Examination revealed superior displacement of the patella with tenderness over the anterior aspect of the knee joint. The knee was locked in extension and neither passive or active flexion was possible. Radiographs demonstrated superior dislocation of the patella held by interlocking osteophytes (Fig. 1). An attempt at closed reduction proved unsuccessful. A magnetic resonance image scan was obtained. This demonstrated that the patellar tendon was intact (Fig. 2b). With this additional information available, a further attempt at closed reduction without anaesthesia or sedation was performed. Hyperextension of the knee and medial pressure allowed the osteophyte to be unlocked and the patella to be relocated. A full range of knee movement was obtained immediately post-reduction. The following day the patient was pain free and fully weight bearing and was discharged from hospital. On review at 1 month, after a course of physiotherapy, the patient had returned to normal activities with no recurrence of her symptoms.
cases of superior dislocation have been reported [2– 7,9 –11]. Most of the cases were reduced closed but a case described by Rao et al. [4] required open reduction. The majority of the reported cases therefore have
2. Discussion Lateral dislocation of the patella is common and well recorded in the literature. In contrast, only isolated * Corresponding author. Tel.: + 44-29-20345306. E-mail address: [email protected] (A. Iorwerth).
Fig. 1. Lateral radiograph of the knee showing a superiorly dislocated patella but the precise location of the fixed osteophytes is not seen.
0020-1383/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved. PII: S 0 0 2 0 - 1 3 8 3 ( 0 0 ) 0 0 1 6 7 - 4
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A. Iorwerth et al. / Injury, Int. J. Care Injured 32 (2001) 167–169
Fig. 2. Coronal magnetic resonance images through the knee showing interlocking of a laterally based lateral femoral condyle osteophyte with an inferior patellar osteophyte (a, b, c). In Fig. 2b and c, the intact patellar tendon is also seen.
required sedation [3,6] or anaesthesia [5,10]. All these cases were due to similar mechanisms of injury, which is a forced contraction of the quadriceps with or without a posteriorly directed force. The latest reports [9,10] describe patients with voluntary superior dislocation secondary to proximal tibiofibular joint fusion and simple osteophytes respectively; here,
arthroscopic resection of the osteophytes was performed to prevent recurrence. Radiographs have been used in all the above cases to confirm the diagnosis of dislocation and also to demonstrate the presence of the interlocking osteophytes which may prevent relocation. Relocation has been achieved by closed and open methods as
A. Iorwerth et al. / Injury, Int. J. Care Injured 32 (2001) 167–169
described above but no previous report describes the use of magnetic resonance imaging (MRI) in locating the osteophytes that prevent reduction. In our case, this investigation allowed precise location so that a further attempt at closed reduction could be performed, thus ‘unlocking’ the patella. This prevented the patient from undergoing an anaesthetic and avoided any open surgical intervention. Previous papers have emphasised that this is a condition which is clinically similar to patellar ligament rupture and needs to be distinguished from it [3 –7,9 – 11]. Older literature claimed that the dislocation was indeed due to such a rupture [2,8]. More recently, however, authors have reported that clinically the patellar tendon remains intact in such an injury [1,3 – 7,9,10] although Rao et al. noticed during open reduction that it was ‘elongated’ [5]. The MRI not only assisted in her treatment but as can be seen in Fig. 2, the ligament is not ruptured or attenuated. The MRI thus, shows for the first time in this type of dislocation that the patellar tendon has actually remained intact during the injury and is not attenuated. This confirms that the injury is due to hyperextension of the knee from forceful contraction of the quadriceps, with or without a posterior force on the inferior pole of the patella, as opposed to a tear in the patellar tendon allowing the patella to be displaced.
.
169
The MRI can, therefore, be useful in assessing the soft tissues, as well as the bony aspects of this injury.
References [1] Bartlett DH, Gilula LA, Murphy WA. Superior dislocation of the patella fixed by interlocked osteophytes. J Bone Jt Surg (Am) 1976;58(6):883– 4. [2] Campbell WC. A Text-Book on Orthopedic Surgery. Philadelphia: W.B. Saunders, 1930:328. [3] Friden T. A case of superior dislocation of the Patella. Acta Orthop Scand 1987;58:429– 30. [4] Hanspal RS. Superior dislocation of the patella. Injury 1985;16(7):487– 8. [5] Rao JP, Meese MA, Irreducible superior dislocation of the patella requiring open reduction., Am. J. Orthop. 1997; 486–88. [6] Roth, McCabe JB. Non-traumatic superior dislocation of the patella. J Emerg Med 1985;3(4):265– 7. [7] Siegel MG, Mac SS. Superior dislocation of the patella with interlocking osteophytes. J Trauma 1982;22(3):253– 4. [8] Speed K. A Text-Book of Fractures and Dislocations. Covering Their Pathology, Diagnosis and Treatment, fourth ed. Philadelphia: Lea and Febiger, 1942:881. [9] Takai S, Yoshino N, Hirasawa Y. Arthroscopic treatment of voluntary superior dislocation of the patella. Arthroscopy 1997;14(7):753– 6. [10] Teuscher DD, Goletz TH. Recurrent atraumatic superior dislaocation of the patella: case report and review of the literature. Arthroscopy 1992;8(4):541– 3. [11] Watson-Jones R. Fractures and Joint Injuries, vol. 2, fifth ed. Edinburgh: Churchill Livingstone, 1976:1056.
Case report
Confirmation of an intact patellar tendon in superior dislocation of the patella using magnetic resonance imaging A. Iorwerth a,*, R. Thomas b, D.J. Shewring a a
Department of Orthopaedics and Trauma, Uni6ersity Hospital of Wales, Heath Park, Cardiff, UK b Morriston Hospital, Morriston, Swansea, UK Accepted 15 August 2000
1. Case report A 72-year-old lady sustained a fall whilst decorating her Christmas tree. Immediately after this she developed pain in her right knee and was unable to bear weight on that leg. The patient denied any previous injury to the knee or any symptoms related to it. Examination revealed superior displacement of the patella with tenderness over the anterior aspect of the knee joint. The knee was locked in extension and neither passive or active flexion was possible. Radiographs demonstrated superior dislocation of the patella held by interlocking osteophytes (Fig. 1). An attempt at closed reduction proved unsuccessful. A magnetic resonance image scan was obtained. This demonstrated that the patellar tendon was intact (Fig. 2b). With this additional information available, a further attempt at closed reduction without anaesthesia or sedation was performed. Hyperextension of the knee and medial pressure allowed the osteophyte to be unlocked and the patella to be relocated. A full range of knee movement was obtained immediately post-reduction. The following day the patient was pain free and fully weight bearing and was discharged from hospital. On review at 1 month, after a course of physiotherapy, the patient had returned to normal activities with no recurrence of her symptoms.
cases of superior dislocation have been reported [2– 7,9 –11]. Most of the cases were reduced closed but a case described by Rao et al. [4] required open reduction. The majority of the reported cases therefore have
2. Discussion Lateral dislocation of the patella is common and well recorded in the literature. In contrast, only isolated * Corresponding author. Tel.: + 44-29-20345306. E-mail address: [email protected] (A. Iorwerth).
Fig. 1. Lateral radiograph of the knee showing a superiorly dislocated patella but the precise location of the fixed osteophytes is not seen.
0020-1383/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved. PII: S 0 0 2 0 - 1 3 8 3 ( 0 0 ) 0 0 1 6 7 - 4
168
A. Iorwerth et al. / Injury, Int. J. Care Injured 32 (2001) 167–169
Fig. 2. Coronal magnetic resonance images through the knee showing interlocking of a laterally based lateral femoral condyle osteophyte with an inferior patellar osteophyte (a, b, c). In Fig. 2b and c, the intact patellar tendon is also seen.
required sedation [3,6] or anaesthesia [5,10]. All these cases were due to similar mechanisms of injury, which is a forced contraction of the quadriceps with or without a posteriorly directed force. The latest reports [9,10] describe patients with voluntary superior dislocation secondary to proximal tibiofibular joint fusion and simple osteophytes respectively; here,
arthroscopic resection of the osteophytes was performed to prevent recurrence. Radiographs have been used in all the above cases to confirm the diagnosis of dislocation and also to demonstrate the presence of the interlocking osteophytes which may prevent relocation. Relocation has been achieved by closed and open methods as
A. Iorwerth et al. / Injury, Int. J. Care Injured 32 (2001) 167–169
described above but no previous report describes the use of magnetic resonance imaging (MRI) in locating the osteophytes that prevent reduction. In our case, this investigation allowed precise location so that a further attempt at closed reduction could be performed, thus ‘unlocking’ the patella. This prevented the patient from undergoing an anaesthetic and avoided any open surgical intervention. Previous papers have emphasised that this is a condition which is clinically similar to patellar ligament rupture and needs to be distinguished from it [3 –7,9 – 11]. Older literature claimed that the dislocation was indeed due to such a rupture [2,8]. More recently, however, authors have reported that clinically the patellar tendon remains intact in such an injury [1,3 – 7,9,10] although Rao et al. noticed during open reduction that it was ‘elongated’ [5]. The MRI not only assisted in her treatment but as can be seen in Fig. 2, the ligament is not ruptured or attenuated. The MRI thus, shows for the first time in this type of dislocation that the patellar tendon has actually remained intact during the injury and is not attenuated. This confirms that the injury is due to hyperextension of the knee from forceful contraction of the quadriceps, with or without a posterior force on the inferior pole of the patella, as opposed to a tear in the patellar tendon allowing the patella to be displaced.
.
169
The MRI can, therefore, be useful in assessing the soft tissues, as well as the bony aspects of this injury.
References [1] Bartlett DH, Gilula LA, Murphy WA. Superior dislocation of the patella fixed by interlocked osteophytes. J Bone Jt Surg (Am) 1976;58(6):883– 4. [2] Campbell WC. A Text-Book on Orthopedic Surgery. Philadelphia: W.B. Saunders, 1930:328. [3] Friden T. A case of superior dislocation of the Patella. Acta Orthop Scand 1987;58:429– 30. [4] Hanspal RS. Superior dislocation of the patella. Injury 1985;16(7):487– 8. [5] Rao JP, Meese MA, Irreducible superior dislocation of the patella requiring open reduction., Am. J. Orthop. 1997; 486–88. [6] Roth, McCabe JB. Non-traumatic superior dislocation of the patella. J Emerg Med 1985;3(4):265– 7. [7] Siegel MG, Mac SS. Superior dislocation of the patella with interlocking osteophytes. J Trauma 1982;22(3):253– 4. [8] Speed K. A Text-Book of Fractures and Dislocations. Covering Their Pathology, Diagnosis and Treatment, fourth ed. Philadelphia: Lea and Febiger, 1942:881. [9] Takai S, Yoshino N, Hirasawa Y. Arthroscopic treatment of voluntary superior dislocation of the patella. Arthroscopy 1997;14(7):753– 6. [10] Teuscher DD, Goletz TH. Recurrent atraumatic superior dislaocation of the patella: case report and review of the literature. Arthroscopy 1992;8(4):541– 3. [11] Watson-Jones R. Fractures and Joint Injuries, vol. 2, fifth ed. Edinburgh: Churchill Livingstone, 1976:1056.