Massive Ossification of the Patellar Fat Pad: An Unusual Cause of Knee Stiffness

Abstract

While stiffness following an injury is usually secondary to soft tissue scarring, a variety of different benign and malignant lesions may restrict range of motion about the knee. We report the unusual case of a patient who presented with a chronic knee extension contracture secondary to a large ossified mass in the anterior aspect of the knee. Radiographs, magnetic resonance imaging, and subsequent histopathology were consistent with a diagnosis of myositis ossificans of the fat pad. Subsequent resection resulted in full motion recovery and resolution of symptoms at 30-month follow-up.

Keywords

heterotopic ossification - knee mass - arthrofibrosis

• References

• 1 Petsche TS, Hutchinson MR. Loss of extension after reconstruction of the anterior cruciate ligament. J Am Acad Orthop Surg 1999; 7 (2) 119-127
• 2 Chen MR, Dragoo JL. Arthroscopic releases for arthrofibrosis of the knee. J Am Acad Orthop Surg 2011; 19 (11) 709-716
• 3 Enneking WF, Rathe R, Cornwall G. Clinical Musculoskeletal Pathology. Gainesville, FL: Office of Medical Informatics, College of Medicine, University of Florida; 1998
• 4 Cipriano CA, Pill SG, Keenan MA. Heterotopic ossification following traumatic brain injury and spinal cord injury. J Am Acad Orthop Surg 2009; 17 (11) 689-697
• 5 Bruijn JD, Sanders RJ, Jansen BR. Ossification in the patellar tendon and patella alta following sports injuries in children. Complications of sleeve fractures after conservative treatment. Arch Orthop Trauma Surg 1993; 112 (3) 157-158
• 6 Bowers Jr KD. Patellar tendon avulsion as a complication of Osgood-Schlatter's disease. Am J Sports Med 1981; 9 (6) 356-359
• 7 Grossfeld SL, Engebretsen L. Patellar tendinitis—a case report of elongation and ossification of the inferior pole of the patella. Scand J Med Sci Sports 1995; 5 (5) 308-310
• 8 Matsumoto H, Kawakubo M, Otani T, Fujikawa K. Extensive post-traumatic ossification of the patellar tendon. A report of two cases. J Bone Joint Surg Br 1999; 81 (1) 34-36
• 9 Tornetta III P, Barbera C. Severe heterotopic bone formation in the knee after tibial intramedullary nailing. J Orthop Trauma 1992; 6 (1) 113-115
• 10 Tyler P, Saifuddin A. The imaging of myositis ossificans. Semin Musculoskelet Radiol 2010; 14 (2) 201-216
• 11 Hanquinet S, Ngo L, Anooshiravani M, Garcia J, Bugmann P. Magnetic resonance imaging helps in the early diagnosis of myositis ossificans in children. Pediatr Surg Int 1999; 15 (3-4) 287-289
• 12 Hait G, Boswick Jr JA, Stone NH. Heterotopic bone formation secondary to trauma (myositis ossificans traumatica). J Trauma 1970; 10 (5) 405-411
• 13 Hosalkar H, Pandya NK, Hsu JE, Kamath AF, Keenan MA. What's new in orthopaedic rehabilitation. J Bone Joint Surg Am 2010; 92 (8) 1805-1812