Abstract
Spontaneous, bilateral, quadriceps tendon rupture is a rare injury. Many predisposing conditions have been reported that contribute to quadriceps tendon degeneration. We report a case of a 42-year-old farmer with spontaneous, bilateral, quadriceps tendon rupture and clear medical history. Clinical and laboratory investigations revealed no risk factors for tendon degeneration but the patient reported that he was exposed locally to methidathion 1 week before the rupture. Methidathion is an organophosphate insecticide commonly used in agriculture that is highly toxic via the dermal route. Methidathion induces lipid pre-oxidation and consequently alters quadriceps tendon blood supply and ultrastructure. The injury was treated with early surgical repair and final outcome was excellent 44 months postoperatively.
Background
This case is the first in the literature to report methidathion as a cause of spontaneous quadriceps tendon rupture. Methidathion is one of the most widely used organophosphate insecticides, making this newly reported side effect interesting not only for orthopaedic surgeons, but for people working in public health programmes and agriculture as well.
Case presentation
A 42-year-old farmer was admitted to the emergency room of our hospital with complaints of sudden pain of both knees and an inability to walk. He reported a burning ache in his left knee while walking downstairs and an inability to maintain his knee extended. The patient fell down and while trying to stand up from the sitting position he had the same symptoms in his right knee. On clinical examination the patient was unable to extend his knees actively. Local tenderness and suprapatellar gaps were found in both knees (fig 1), establishing the diagnosis of bilateral quadriceps tendon rupture. Plain radiographs demonstrated patella tendon calcification near the tibial tuberosity in both knees and low riding and anterior tilting of both patellae (fig 2). The patient did not report any remarkable medical history that could predispose to tendon rupture. The only fact that the patient could relate to his injury was that during spraying of his orange trees his trousers got wet with methidathion, an organophosphate insecticide. In total, the patient was locally exposed to methidathion 2 h a day for 2 days, 1 week before the spontaneous bilateral quadriceps tendon rupture.
Figure 1.
Suprapatellar gaps were found in both knees, establishing the clinical diagnosis of spontaneous bilateral quadriceps tendon.
Figure 2.
Plain radiographs demonstrated patella tendon calcification near the tibial tuberosity in both knees and low riding and anterior tilting of both patellae.
Investigations
Clinical and laboratory (haematological and metabolic profile) investigations failed to reveal any of the risk factors that have been reported in the literature for quadriceps tendon rupture (diabetes mellitus, chronic renal failure, hyperparathyroidism, atherosclerosis, gout, pseudo-gout, hyperlipidaemia, lupus erythematosus, systemic use of steroids, local injections of steroids, obesity, sports activity).1
Treatment
The patient was treated surgically. A longitudinal incision was made to explore the lesion in both knees. Both quadriceps tendons were found degenerative and ruptured just proximal to the superior pole of the patella (fig 3). The tendons were repaired using three suture anchors in each knee, loaded with No. 2 non-absorbable suture. The extensor retinacula were also repaired using No. 2–0 absorbable sutures (fig 4). Postoperatively, both knees were immobilised in full extension with plasters for 6 weeks. Subsequently, the plasters were removed and replaced by hinged knee braces. Knee range of motion 0–60° was allowed for 4 weeks and 0–90° for another 4 weeks, and the braces were then removed. Weight bearing as tolerated was permitted immediately after surgery using crutches.
Figure 3.
The quadriceps tendon is degenerative and torn just proximal to the superior pole of the patella.
Figure 4.
The quadriceps tendon after the repair is completed.
Outcome and follow-up
The postoperative period was uneventful. The patient regained full active and passive range of motion at 6 months and returned to his work and to the pre-injury level of activity 9 months postoperatively. Forty-four months after the operation the patient is still asymptomatic and knee motion is within normal limits bilaterally.
Discussion
Simultaneous bilateral quadriceps tendon rupture is not a common injury. It is highly correlated with chronic metabolic disorders such as diabetes, hyperparathyroidism, gout, chronic renal failure, lupus erythematodus, systematic use of steroids and other conditions.1 Obesity and sports activity have also been reported as risk factors. All these predisposing conditions contribute to degeneration of the quadriceps tendon and therefore possibly lead to rupture.
Our case is the first in the recent literature (over the last 20 years) without known underlying risk factors. In the early 1980s, Dhar2 and MacEachern and Plewes3 reported a few cases without mentioning the medical history of the patients in detail. As a result the existence of predisposing conditions, or not, in these cases is unclear.
It has been demonstrated that approximately 50% of the healthy tendon has to be severed in order to obtain rupture.4 Nowadays it is commonly accepted that the tendon’s ultrastructure impairment by a risk factor is crucial for close quadriceps tendon rupture.1
In our case, all clinical and laboratory tests were negative for the above mentioned predisposing conditions. Consequently, we thoroughly reassessed the injury history and found that the patient had been exposed locally to methidathion during the previous days.
Methidathion is one of the most widely used organophosphate insecticides for public health programmes and agricultural purposes.5 It is highly toxic via the oral route and via the dermal route as well, with reported dermal LD50 values of 85–94 mg/kg in the rat (milligrams of substance per kilogram of body weight that kills 50% of the test animals).6 Maddy et al7 showed that the greatest exposure potential of humans to methidathion was through the skin.
Several studies reported that methidathion may induce oxidative stress and lipid peroxidation.5,7–9 Oxidative stress is a condition of increased oxidant production in cells, characterised by the release of free radicals and resulting in cellular degeneration. Free radicals can react with key components of cells, including DNA, lipids, and protein, resulting in cellular damage. When free radicals react with lipids we have lipid peroxidation which is a well established molecular mechanism of cellular injury.
It has been shown that oxidative stress, lipid peroxidation and reactive oxygen species (free radicals) are triggers and essential mediators of apoptosis (programmed cell death).10–13 Simonin et al11 reported that oxidative stress altered proteoglycan anabolism and oxidised collagen in the Achilles tendon, while Wang et al12 showed that oxidative stress plays an important role in tendon matrix degradation possibly through upregulation of matrix metalloproteinase 1.
Moreover, methidathion has been shown to cause vascular wall damage.5 Sufficient blood supply is of great importance for a healthy tendon. Yepes et al14 demonstrated that the poorest vascularity of the quadriceps tendon was noted in a zone located between 1–2 cm from the insertion of the patella. They reported14 that hypovascularity may determine the site of spontaneous ruptures of the quadriceps tendon. This finding has been corroborated by other authors1–3 and it is in accordance with our case.
In conclusion, closed spontaneous quadriceps tendon rupture occurs in the basis of tendon degeneration. Orthopaedic surgeons dealing with this clinical entity ought to look for the predisposing conditions that contribute to tendon degeneration. To our knowledge, this is the first case of simultaneous, bilateral (or unilateral), quadriceps tendon rupture reported in the literature caused by exposure to methidathion.
Learning points
Orthopaedic surgeons dealing with closed quadriceps tendon rupture ought to look for the predisposing conditions that contribute to tendon degeneration.
Methidathion is an organophosphate insecticide commonly used in agriculture that could cause spontaneous quadriceps tendon rupture after skin absorption.
Lipid peroxidation is the molecular mechanism through which methidathion can damage the blood supply to the tendon and alter the structure of the tendon.
Early surgical intervention of spontaneous, bilateral, quadriceps tendon repair lead to satisfactory clinical outcome.
Footnotes
Competing interests: none.
Patient consent: Patient/guardian consent was obtained for publication
REFERENCES
- 1.Neubauer T, Wagner M, Potshka T, et al. Bilateral simultaneous rupture of the quadriceps tendon: a diagnostic pitfall? Report of three cases and meta analysis of the literature. Knee Surg Sports Traumatol Arthrosc 2007; 15: 43–53 [DOI] [PubMed] [Google Scholar]
- 2.Dhar S. Bilateral, simultaneous, spontaneous rupture of the quadriceps tendon. A report of 3 cases and a review of the literature. Injury 1988; 19: 7–8 [DOI] [PubMed] [Google Scholar]
- 3.MacEachern AG, Plewes JL. Bilateral simultaneous spontaneous rupture of the quadriceps tendons. Five case reports and a review of the literature. J Bone Joint Surg Br 1984; 66: 81–3 [DOI] [PubMed] [Google Scholar]
- 4.McMaster Tendon and muscle ruptures. Clinical and experimental studies on the causes and location of subcutaneous ruptures. J Bone Joint Surg Am 1933; 15–A: 705–22 [Google Scholar]
- 5.Yavuz T, Delibas N, Yildirim B, et al. Vascular wall damage in rats induced by organophosphorus insecticide methidathion. Toxicol Lett 2005; 155: 59–64 [DOI] [PubMed] [Google Scholar]
- 6.Gallo MA, Lawryk NJ. Organic phosphorus pesticides. : Hayes WJ, Jr, Laws ER, Jr, eds. Handbook of pesticide toxicology. New York: Academic Press, 1991: 5 [Google Scholar]
- 7.Maddy KT, Gibbons D, Richmond DM, et al. Potential exposure of leader/applicators to methidathion (Supracide) during applications to citrus in Riverside County, California in 1982. Sacramento: California Department of Food and Agriculture, Division of Pest Management, 1983: 5–83 [Google Scholar]
- 8.Altuntas I, Delibas N, Sutcu R. The effects of organophosphate insecticide methidathion on lipid peroxidation and anti-oxidant enzymes in rat erythrocytes: role of vitamins E and C. Hum Exp Toxicol 2002; 21: 681–5 [DOI] [PubMed] [Google Scholar]
- 9.Sutcu R, Altuntas I, Yildirim B, et al. The effects of subchronic methidathion toxicity on rat liver: role of antioxidant vitamins C and E. Cell Biol Toxicol 2006; 22: 221–7 [DOI] [PubMed] [Google Scholar]
- 10.Bestwick CS, Maffulli N. Reactive oxygen species and tendon problems: review and hypothesis. Sports Med Arthroscopy Rev 2000; 8: 6–16 [Google Scholar]
- 11.Simonin MA, Gegout-Pottie P, Minn A, et al. Pefloxacin-induced achilles tendon toxicity in rodents: biochemical changes in proteoglycan synthesis and oxidative damage to collagen. Antimicrob Agents Chemother 2000; 44: 867–72 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Wang F, Murrell GA, Wang MX. Oxidative stress-induced c-Jun N-terminal kinase (JNK) activation in tendon cells upregulates MMP1 mRNA and protein expression. J Orthop Res 2007; 25: 378–89 [DOI] [PubMed] [Google Scholar]
- 13.Yuan J, Murrell GA, Trickett A, et al. Involvement of cytochrome c release and caspase-3 activation in the oxidative stress-induced apoptosis in human tendon fibroblasts. Biochim Biophys Acta 2003; 1641: 35–41 [DOI] [PubMed] [Google Scholar]
- 14.Yepes H, Tang M, Morris SF, et al. Relationship between hypovascular zones and patterns of ruptures of the quadriceps tendon. J Bone Joint Surg Am 2008; 90: 2135–41 [DOI] [PubMed] [Google Scholar]