Grand Rounds Vol 7 pages 70–74 Speciality: Accident and emergency medicine and surgery (including trauma); Orthopaedic surgery Article Type: Case Report DOI: 10.1102/1470-5206.2007.0021 ß 2007 e-MED Ltd

Bilateral patellar tendon rupture: an unusual case of trampoline injury Alex Hotouras, Nemandra Sandiford and Sudhir Rao Department of Orthopedic Surgery, Queen Mary Hospital, Sidcup, Kent, UK Corresponding address: Dr Alex Hotouras, Department of Orthopedic Surgery, Queen Mary Hospital, Sidcup, Kent, UK. E-mail: [email protected] Date accepted for publication 17 October 2007

Abstract We report the case of a healthy 44-year-old gentleman who sustained bilateral patellar tendon rupture while jumping on a trampoline. Although this kind of injury has been reported in the literature previously, it is extremely rare in healthy individuals. We believe it is the first documented case associated with the use of a trampoline.

Keywords Bilateral patella tendon rupture; trampoline injuries.

Case report A 44-year-old man presented to the Accident and Emergency Department with bilateral knee pain of a few hours duration. The pain started while he was on the trampoline and he felt his knees giving way while in the air, off the trampoline. He did not report any direct impact to his knees. He was unable to land on his feet and bear weight. He was otherwise fit and well without any previous knee problems. On examination, there was no obvious swelling around his knee joints but he was unable to straight leg raise and the patella clinically appeared to be displaced proximally bilaterally. A clinical diagnosis of bilateral patellar tendon rupture was made and was confirmed radiologically by the presence of patella alta. He was scheduled for an emergency repair of his patellar tendons. Both tendons were significantly damaged and the retinacular tear extended on either side. The retinacula were individually sutured, which restored the soft tissue tension, after which the patellar tendon repair was done using the modified Kessler technique (Fig. 1). Because of the strong action of his quadriceps, the repair was protected with cerclage figure of eight wire (Figs. 2 and 3). At the end of the procedure, there was good stabilisation of the patella and the knee could be flexed to 90 degrees without significant distraction of the patella. The patient had bilateral above knee casts in full extension for 4 weeks post-operatively after which he was put into a lockable brace for a further 3 weeks. He was allowed to mobilise bearing his full weight but was advised to avoid any straight leg raising. At 4 weeks post-operatively, he started physiotherapy sessions consisting of patellar mobilisation and flexion techniques and was This paper is available online at http://www.grandrounds-e-med.com. In the event of a change in the URL address, please use the DOI provided to locate the paper.

Bilateral patellar tendon rupture

71

Fig. 1. Intra-operative view of the repaired tendon.

Fig. 2. Intra-operative view of the repair and reinforcement with a wire cerclage for the right patellar tendon.

given exercises to improve his range of flexion at home. At around 10 weeks post-operatively, he could flex his knees to around 120–130 degrees. He continued his excellent recovery and at 12 weeks he was able to perform a straight leg raise bilaterally and ambulate using a normal gate. The wires were removed after 5 months due to skin irritation and he was eventually discharged from follow up. A radiograph of his knees prior to discharge is shown in Fig. 4. A histological examination of the excised tissue showed focal permeation by scanty lymphomononuclear cells and neutrophils with presence of nuclear debris. Those features were consistent with degenerative changes.

Discussion The extensor mechanism of the knee can be disrupted by patellar fractures and rupture of the quadriceps or patellar tendon[1]. Rupture of the patellar tendon is the least common of these injuries and requires a force of 17.5 times the body weight[2]. It is usually seen in young adults as a result of overloading the extensor mechanism during sporting activities, for example landing after a jump[3]. In this scenario, the knee is in the flexed position and opposes the

72

A. Hotouras et al.

Fig. 3. Radiographs of both knees showing the fixation of the patella to the tibial tubercle by wires.

action of the quadriceps. The patellar tendon, especially the site of its proximal insertion, is under greater stress than the quadriceps tendon and, therefore, more likely to rupture[3,4]. The rupture is the end-result of long standing degeneration secondary to repetitive microtrauma[1,3]. Histopathological studies of ruptured tendons demonstrated changes consistent with chronic inflammation and degeneration[5]. Bilateral patellar tendon rupture is a rare entity usually seen in men in their late thirties[1,3]. Around 50 cases have been reported in the literature and about two-thirds are traumatic or sports related[1]. The remaining one-third of the cases are atraumatic, usually associated with the use of corticosteroids, connective tissue disorders, chronic renal failure, diabetes and hyperparathyroidism[1,6,7]. In the majority of cases, the rupture occurred at the insertion of the tendon to the inferior pole of the patella for the reasons explained above[1,3]. Rupture can also occur through the substance of the tendon or much less frequently through its insertion into the tibia[1,3]. The diagnosis of bilateral patellar tendon rupture may be missed because of the symmetrical findings. In the study by Siwek and Rao, about a third of these injuries were misdiagnosed on initial examination and about a fifth were repaired more than 2 weeks after the initial injury[8]. A delay in diagnosis is associated with proximal retraction of the patella, scarring, complicated repair often requiring the use of grafts, delayed recovery and possibly decreased long term function[8].

Bilateral patellar tendon rupture

73

Fig. 4. Knee radiographs after removal of wires.

In conclusion, bilateral patellar tendon rupture is a rare diagnosis and can be easily missed because of the symmetrical findings. The case that we reported is both interesting and unusual in the sense that it occurred in a healthy adult, following chronic asymptomatic degeneration, without any direct impact to the knees, while jumping on a trampoline.

Teaching point Bilateral patellar tendon rupture is a rare diagnosis which can be easily missed because of the symmetrical findings. It should be treated as an orthopaedic emergency since any delay may make the repair more difficult, delay recovery and affect long term function.

References 1. Rose P, Frassica F. Atraumatic bilateral patellar tendon rupture. J Bone Joint Surg 2001; 83: 1382–6.

74

A. Hotouras et al. 2. Zernicke RF, Garhammer J, Jobe FW. Human patellar-tendon rupture. J Bone Joint Surg Am 1977; 59: 179–83. 3. Annunziata C. Patellar tendon rupture. http://www.emedicine.com 4. Van Glabbeek F, De Grof E, Boghemans J. Bilateral patellar tendon rupture: case report and literature review. J Trauma 1992; 33: 790–2. 5. Kannus P, Jozsa L. Histopathological changes preceding spontaneous rupture of a tendon. J Bone Joint Surg Am 1991; 73: 1507–25. 6. Prasad S, Lee A, Clarnette R, Faull R. Spontaneous, bilateral patellar tendon rupture in a woman with previous Achilles tendon rupture and SLE. Rheumatology 2003; 42: 905–6. 7. Clark SC, Jones MW, Choudhury RR, Smith E. Bilateral patellar tendon rupture secondary to repeated local steroid injections. J Accid Emerg Med 1995; 12: 300–1. 8. Siwek CW, Rao JP. Rupture of the extensor mechanism of the knee joint. J Bone Joint Surg Am 1981; 63: 932–7.