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Bilateral stress fracture of the patellae: A case report
The Knee 13 (2006) 164 – 166 www.elsevier.com/locate/knee
Short communication
Bilateral stress fracture of the patellae: A case report Mario Carneiro *, Caio Augusto de Souza Nery, Luiz Aurelio Mestriner Department of Orthopaedics and Traumatology at the Federal University of Sao Paulo, Paulista Medical School, Sao Paulo, Brazil Received 26 June 2005; received in revised form 9 August 2005; accepted 15 August 2005
Abstract A case of bilateral simultaneous stress fracture of the patella is presented in a 64 year old Marathon runner sustained when he slipped off a kerb whilst out walking. This was confirmed on Xray and treated by tension band wiring using the AO technique. He had an excellent result returning to normal function in both knees. This case is unusual since the fractures were not due to osteoporosis, as would be expected in this age group. D 2005 Elsevier B.V. All rights reserved. Keywords: Patella; Stress fracture
1. Introduction The stress fracture syndrome is becoming increasingly common because of the growing number of people involved in sports practice, especially jogging [1,2]. Such repetitive exercise may contribute to the development of stress fracture [3]. It was initially described by Breithaupt in 1855 after examining soldiers’ feet after long treks [2– 5]. The stress fracture of the patellae is a rare event. It was first described by Muller in 1943 [6]. The purpose of this paper is to present the case of a 64-year-old marathon runner, who suffered stress fractures in both patellae simultaneously. This case is rare because the patient experienced stress fractures at a later stage of life than is usual in people with stress fractures without associated osteoporosis.
2. Case report A 64-year-old white male marathon runner had previously run 15 km/day. He had no previous general medical disorders or complaints relating to the knees. When stepping onto the pavement, he slipped and, with knees semi-flexed, * Corresponding author. Rua Macau 300, Sa˜o Paulo, SP, Brazil CEP 04032-020. E-mail address: [email protected] (M. Carneiro). 0968-0160/$ - see front matter D 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.knee.2005.08.003
heard a crack coming from the right knee. He attempted to prop up on the contralateral knee, but heard a second crack, also followed by functional disability. He fell backwards and could not move without assistance. The clinical examination showed bilateral joint effusions, inability to extend the knees and a gap at the center of both patellae. Arthrocentesis produced bloody fluid with fat droplets. Roentgenographic examination showed transverse fractures in both patellae, with marked displacement (Fig. 1). Dual energy absorptiometry X-rays showed no evidence of osteoporosis. Osteosynthesis of both patellae was performed using a tension band technique (AO), in order to achieve anatomical reduction (Fig. 2). During the procedure, no significant alteration of the bone fragments or on the articular surfaces was observed. The patient achieved 100 degrees of flexion in both knees at the end of the first postoperative month. After 3 months, when reaching a range of motion of 130 degrees, he went back to his training schedule. One year after surgery, he resumed competitive marathon running.
3. Discussion Stress fracture of the patella is a rare event, which was first described by Muller in 1943 [6]. Orava et al. [2] and Matheson et al. [1] reported on a large series of stress
M. Carneiro et al. / The Knee 13 (2006) 164 – 166
fractures (142 and 320 participants, respectively), but no cases of patellar stress fracture were included. Most authors agree that stress fractures most frequently affect the tibia [1,2,5,7]; however, to our knowledge, no data has been published on the incidence of the patellar stress fracture. Repetitive and intense stress are among the most common factors leading to a stress fracture of the patella. However, the stress fracture should not be considered as a purely static condition, in which a material under recurrent loading suffers fatigue failure [5,6]. The imbalance between repetitive stress and the physiological ability of repair contributes decisively to this process. However, bone tissue responds to forces acting on it, and adapts to loading. When starting a training program or reinforcing a pre-existing one, risk of stress fracture is increased [2,3,8]. Previous studies have established an association between stress fractures and hormonal abnormalities (hypoestrogenism [9]) and alterations in calcium metabolism (low ingestion [9], osteoporosis [10,12]). The quadriceps tendon and patellar ligament act in opposite directions to produce force vectors which result in compression of the patella against the femoral condyles. These events are potentially traumatic on the semi-flexed knee (30- – 43-), when a sudden increase in the quadriceps strength is necessary [6]. A high number of stress fractures have been attributed to the practice of jogging, especially in the tibia, but stress fractures of the patella do not appear to be particularly related to this activity [7]. Stress fractures of the patella are most commonly seen in young athletes (second to fourth decade [6,10,12]) and,
165
Fig. 2. Radiograph showing the reduction by AO method: A – anteriorposterior view. B – lateral view.
frequently, patellar tendonitis occurs before the appearance of the fracture [6,12]. This reported case is particularly unusual because of its bilateral and simultaneous occurrence in a competitive runner belonging to an older age group (seventh decade). To the authors’ knowledge, the only published reference to bilateral stress fracture of the patella was in a 34-year-old basketball player with previous symptoms of severe patellar tendonitis [12]. We believe that these findings suggest that the stress fracture occurred due to insufficiency (in an already pathologic bone [10,11]), whereas, in our case, the material collected during the surgical procedure did not present any unusual bone pathology, which suggests that it was a stress fracture caused by fatigue, in an otherwise normal bone.
References
Fig. 1. Knee radiograph showing the fractures: A – anterior-posterior view. B – lateral view.
[1] Matheson GO, Clement DB, McKenzie DC, Tauton JE, LloydSmith DR, Maclntire JG. Stress fractures in athletes. A study of 320 cases. Am J Sports Med 1987;15:46 – 58. [2] Orava S, Puranen J, Ala-Ketola L. Stress fractures causes by physical exercise. Acta Orthop Scand 1978;49:19 – 27. [3] Belkin SC. Stress fractures in athletes. Orthop Clin North Am 1980;11:735 – 42. [4] Hallel T, Amit S, Segal D. Fatigue fractures of tibial and femoral shaft in soldiers. Clin Orthop 1976;118:35 – 43. [5] Stanitski CL, McMaster JH, Scranton PE. On the nature of stress fractures. Am J Sports Med 1978;6:391 – 6.
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M. Carneiro et al. / The Knee 13 (2006) 164 – 166
[6] Teitz CC, Harrington RM. Patellar stress fracture. Am J Sports Med 1992;20:761 – 5. [7] Bennel KL, Malcom SA, Thomas SA, Wark JD, Brukner PD. The incidence and distribution of stress fractures in competitive track and field athletes. A twelve-month prospective study. Am J Sports Med 1996;24:211 – 7. [8] Baker J, Frankel VH, Burstein A. Fatigue fracture: biomechanical considerations. J Bone Joint Surg 1972;54:1345 – 6.
[9] Kadel NJ, Teitz CC, Kronmal RA. Stress fractures in ballet dancers. Am J Sports Med 1992;20:445 – 9. [10] Devas MB. Stress fracture of the patella. J Bone Joint Surg 1980;42:71 – 4. [11] Jerosch JG, Castro WHM, Jantea C. Stress fractures of the patella. Am J Sports Med 1989;17:579 – 80. [12] Tibone JE, Lombardo SJ. Bilateral fracture of the inferior pole of the patellae in a basketball player. Am J Sports Med 1981;9:215 – 6.
Short communication
Bilateral stress fracture of the patellae: A case report Mario Carneiro *, Caio Augusto de Souza Nery, Luiz Aurelio Mestriner Department of Orthopaedics and Traumatology at the Federal University of Sao Paulo, Paulista Medical School, Sao Paulo, Brazil Received 26 June 2005; received in revised form 9 August 2005; accepted 15 August 2005
Abstract A case of bilateral simultaneous stress fracture of the patella is presented in a 64 year old Marathon runner sustained when he slipped off a kerb whilst out walking. This was confirmed on Xray and treated by tension band wiring using the AO technique. He had an excellent result returning to normal function in both knees. This case is unusual since the fractures were not due to osteoporosis, as would be expected in this age group. D 2005 Elsevier B.V. All rights reserved. Keywords: Patella; Stress fracture
1. Introduction The stress fracture syndrome is becoming increasingly common because of the growing number of people involved in sports practice, especially jogging [1,2]. Such repetitive exercise may contribute to the development of stress fracture [3]. It was initially described by Breithaupt in 1855 after examining soldiers’ feet after long treks [2– 5]. The stress fracture of the patellae is a rare event. It was first described by Muller in 1943 [6]. The purpose of this paper is to present the case of a 64-year-old marathon runner, who suffered stress fractures in both patellae simultaneously. This case is rare because the patient experienced stress fractures at a later stage of life than is usual in people with stress fractures without associated osteoporosis.
2. Case report A 64-year-old white male marathon runner had previously run 15 km/day. He had no previous general medical disorders or complaints relating to the knees. When stepping onto the pavement, he slipped and, with knees semi-flexed, * Corresponding author. Rua Macau 300, Sa˜o Paulo, SP, Brazil CEP 04032-020. E-mail address: [email protected] (M. Carneiro). 0968-0160/$ - see front matter D 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.knee.2005.08.003
heard a crack coming from the right knee. He attempted to prop up on the contralateral knee, but heard a second crack, also followed by functional disability. He fell backwards and could not move without assistance. The clinical examination showed bilateral joint effusions, inability to extend the knees and a gap at the center of both patellae. Arthrocentesis produced bloody fluid with fat droplets. Roentgenographic examination showed transverse fractures in both patellae, with marked displacement (Fig. 1). Dual energy absorptiometry X-rays showed no evidence of osteoporosis. Osteosynthesis of both patellae was performed using a tension band technique (AO), in order to achieve anatomical reduction (Fig. 2). During the procedure, no significant alteration of the bone fragments or on the articular surfaces was observed. The patient achieved 100 degrees of flexion in both knees at the end of the first postoperative month. After 3 months, when reaching a range of motion of 130 degrees, he went back to his training schedule. One year after surgery, he resumed competitive marathon running.
3. Discussion Stress fracture of the patella is a rare event, which was first described by Muller in 1943 [6]. Orava et al. [2] and Matheson et al. [1] reported on a large series of stress
M. Carneiro et al. / The Knee 13 (2006) 164 – 166
fractures (142 and 320 participants, respectively), but no cases of patellar stress fracture were included. Most authors agree that stress fractures most frequently affect the tibia [1,2,5,7]; however, to our knowledge, no data has been published on the incidence of the patellar stress fracture. Repetitive and intense stress are among the most common factors leading to a stress fracture of the patella. However, the stress fracture should not be considered as a purely static condition, in which a material under recurrent loading suffers fatigue failure [5,6]. The imbalance between repetitive stress and the physiological ability of repair contributes decisively to this process. However, bone tissue responds to forces acting on it, and adapts to loading. When starting a training program or reinforcing a pre-existing one, risk of stress fracture is increased [2,3,8]. Previous studies have established an association between stress fractures and hormonal abnormalities (hypoestrogenism [9]) and alterations in calcium metabolism (low ingestion [9], osteoporosis [10,12]). The quadriceps tendon and patellar ligament act in opposite directions to produce force vectors which result in compression of the patella against the femoral condyles. These events are potentially traumatic on the semi-flexed knee (30- – 43-), when a sudden increase in the quadriceps strength is necessary [6]. A high number of stress fractures have been attributed to the practice of jogging, especially in the tibia, but stress fractures of the patella do not appear to be particularly related to this activity [7]. Stress fractures of the patella are most commonly seen in young athletes (second to fourth decade [6,10,12]) and,
165
Fig. 2. Radiograph showing the reduction by AO method: A – anteriorposterior view. B – lateral view.
frequently, patellar tendonitis occurs before the appearance of the fracture [6,12]. This reported case is particularly unusual because of its bilateral and simultaneous occurrence in a competitive runner belonging to an older age group (seventh decade). To the authors’ knowledge, the only published reference to bilateral stress fracture of the patella was in a 34-year-old basketball player with previous symptoms of severe patellar tendonitis [12]. We believe that these findings suggest that the stress fracture occurred due to insufficiency (in an already pathologic bone [10,11]), whereas, in our case, the material collected during the surgical procedure did not present any unusual bone pathology, which suggests that it was a stress fracture caused by fatigue, in an otherwise normal bone.
References
Fig. 1. Knee radiograph showing the fractures: A – anterior-posterior view. B – lateral view.
[1] Matheson GO, Clement DB, McKenzie DC, Tauton JE, LloydSmith DR, Maclntire JG. Stress fractures in athletes. A study of 320 cases. Am J Sports Med 1987;15:46 – 58. [2] Orava S, Puranen J, Ala-Ketola L. Stress fractures causes by physical exercise. Acta Orthop Scand 1978;49:19 – 27. [3] Belkin SC. Stress fractures in athletes. Orthop Clin North Am 1980;11:735 – 42. [4] Hallel T, Amit S, Segal D. Fatigue fractures of tibial and femoral shaft in soldiers. Clin Orthop 1976;118:35 – 43. [5] Stanitski CL, McMaster JH, Scranton PE. On the nature of stress fractures. Am J Sports Med 1978;6:391 – 6.
166
M. Carneiro et al. / The Knee 13 (2006) 164 – 166
[6] Teitz CC, Harrington RM. Patellar stress fracture. Am J Sports Med 1992;20:761 – 5. [7] Bennel KL, Malcom SA, Thomas SA, Wark JD, Brukner PD. The incidence and distribution of stress fractures in competitive track and field athletes. A twelve-month prospective study. Am J Sports Med 1996;24:211 – 7. [8] Baker J, Frankel VH, Burstein A. Fatigue fracture: biomechanical considerations. J Bone Joint Surg 1972;54:1345 – 6.
[9] Kadel NJ, Teitz CC, Kronmal RA. Stress fractures in ballet dancers. Am J Sports Med 1992;20:445 – 9. [10] Devas MB. Stress fracture of the patella. J Bone Joint Surg 1980;42:71 – 4. [11] Jerosch JG, Castro WHM, Jantea C. Stress fractures of the patella. Am J Sports Med 1989;17:579 – 80. [12] Tibone JE, Lombardo SJ. Bilateral fracture of the inferior pole of the patellae in a basketball player. Am J Sports Med 1981;9:215 – 6.