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Lunate Osteochondroma: A Case Report
Lunate Osteochondroma: A Case Report Takehiko Takagi, MD, Takashi Matsumura, MD, Tateru Shiraishi, MD, Tochigi, Japan
We report a case of osteochondroma of the lunate. A 16-year-old boy had a 6-year history of irritable snapping of the right wrist associated with numbness of the ipsilateral middle finger. At surgery we found that the median nerve became caught on the lunate osteochondroma while the wrist was extended and slipped over it when the wrist was flexed rapidly, thereby causing a snapping phenomenon. The symptoms disappeared completely after the protruding lesion was excised. Several cases of solitary carpal osteochondroma have been reported previously. (J Hand Surg 2005;30A:693– 695. Copyright © 2005 by the American Society for Surgery of the Hand.) Key words: Carpal bone, lunate osteochondroma, median nerve, snapping wrist.
A solitary osteochondroma of the carpal bones is very rare. A review of the literature showed a few cases in the scaphoid,1– 6 1 in the capitate,7 and 1 in the trapezium.8
Case Report A 16-year-old boy had a 6-year history of irritable snapping in the right wrist associated with numbness of the ipsilateral middle finger. No previous event of trauma was noted. The symptoms occurred on quick flexion of the extended wrist such as when shooting a basketball. He was referred to our outpatient clinic in November 2003. Physical examination showed a mass measuring approximately 2.5 cm in diameter on the palmar aspect of the wrist. A Semmes-Weinstein monofilament test showed diminished light-touch sensation From the Department of Orthopaedic Surgery, Saiseikai Utsunomiya Hospital, Utsunomiya, Tochigi, Japan. Received for publication February 1, 2005; accepted in revised form April 21, 2005. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Corresponding author: Takehiko Takagi, MD, Department of Orthopaedic Surgery, Saiseikai Utsunomiya Hospital, 911-1 Takebayashi-machi, Utsunomiya, Tochigi 321-0974, Japan; e-mail: [email protected]. Copyright © 2005 by the American Society for Surgery of the Hand 0363-5023/05/30A04-0007$30.00/0 doi:10.1016/j.jhsa.2005.05.001
on the right middle finger. Percussion of the mass elicited radiating numbness in the same digit. The thenar musculature did not appear atrophic and manual muscle testing of thumb opposition showed that its strength was equivalent to that of the other side. The range of wrist flexion was reduced to 40° as opposed to 80° on the unaffected side; however, no other motions including wrist extension, radial flexion, and ulnar flexion were reduced compared with the other side. Preoperative imaging showed a thick bony mass containing bone marrow broadly protruding from the volar aspect of the lunate (Figs. 1A, 2). No other bony lesions were identified on plain radiographs of the extremities including those of the opposite wrist. There was no family history of skeletal dysplasia. One month after referral the bony lesion was excised. After the proximal portion of the flexor retinaculum was divided the median nerve was found to be compressed by the bony protrusion from the ulnar side and by the flexor digitorum superficialis muscle belly from above. There was synovial proliferation around the nerve indicating chronic inflammation between the flexor tendons and the bony lesion. The incision of the joint capsule disclosed a bone tumor measuring approximately 1.5 by 1.0 cm that was covered by cartilage (Fig. 3). The lunate articular cartilage appeared almost completely normal. The The Journal of Hand Surgery
693
694
The Journal of Hand Surgery / Vol. 30A No. 4 July 2005
Figure 1. (A) Preoperative radiographs of the right wrist showing a dense bony lesion protruding from the palmar aspect of the lunate. (B) Radiographs 1 year after surgery showing that the bony lesion has been excised successfully (arrow).
snapping phenomenon was reproduced by the median nerve and the flexor tendons rubbing against the tip of the bone tumor when the extended wrist was flexed rapidly. The specimen from the excised lesion showed a cartilage cap overlying a layer of normal cancellous ossification, representing the typical pathologic findings of osteochondroma. The surface of the exposed cancellous bone was smoothed with a bone file and we expected fibrocartilaginous regeneration over the surface to occur. Both the snapping and numbness disappeared completely and they have not recurred more than 1 year after surgery. The range of wrist flexion increased to 75°. Postoperative plain
radiographs of the affected wrist showed that the bone tumor was excised successfully (Fig. 1B).
Discussion Solitary osteochondroma is the most common primary bone tumor; however, it rarely develops in the carpal bones. There have been reports of a few cases involving the scaphoid,1– 6 1 in the capitate,7 and 1 in the trapezium.8 Snapping wrist is a rare phenomenon that has been reported only occasionally since Marti9 first described the condition in 1960. Snapping phenomenon involving
Figure 2. Computed tomography scans showing that the bony lesion contains bone marrow (arrow). Left, sagittal view; right, axial view. C, capitate; L, lunate; R, radius; S, scaphoid; U, ulna.
Takagi, Matsumura, and Shiraishi / Lunate Osteochondroma With Snapping Wrist
695
usually occurred while the patient was shooting a basketball. The snapping phenomenon may be characteristic of the lunate osteochondroma located at the center of the carpus.
References
Figure 3. Intraoperative photograph taken with the joint capsule held open showing that the bone tumor measuring 1.5 by 1.0 cm is covered by a so-called cartilage cap (arrow).
the wrist joint may occur during finger, wrist, or forearm motions.10 In the present case the snapping phenomenon was reproduced during surgery by rubbing of the median nerve against the protruding bone tumor when the extended wrist was flexed rapidly. This mechanism of snapping can be attributed to a movement that
1. Harris NJ, Bell MJ. Bilateral scaphoid exostoses. J Hand Surg 1995;20B:745. 2. Medlar RC, Sprague HH. Osteochondroma of the carpal scaphoid. J Hand Surg 1979;4:150 –151. 3. Rimmer SG, Bhoora IG, Hooper G. Scaphoid exostosis and radio-carpal osteoarthrosis. J Hand Surg 1995;20B:741–744. 4. Spinner RJ, Spinner M. Superficial radial nerve compression due to a scaphoid exostosis. J Hand Surg 1996;21B:781– 782. 5. Stahl S, Rayek S. Scaphoid osteochondroma with scapholunate dissociation—a case report. Hand Surg 2000;5:73–75. 6. van Alphen JC, te Slaa RL, Eulderink F, Obermann WR. Solitary osteochondroma of the scaphoid: a case report. J Hand Surg 1996;21A:423– 425. 7. Malhotra R, Maheshwari J, Dinda AK. A solitary osteochondroma of the capitate bone: a case report. J Hand Surg 1992;17A:1082–1083. 8. Heiple KG. Carpal osteochondroma. J Bone Joint Surg 1961; 43A:861– 864. 9. Marti T. [Snapping wrist and carpal tunnel syndrome.] Sci Prog 1960;90:986 –988. 10. Ogino T, Kato H, Ohshio I. Trigger wrist induced by finger movement. Pathogenesis and differential diagnosis. Handchir Mikrochir Plast Chir 1994;26:3– 6.
We report a case of osteochondroma of the lunate. A 16-year-old boy had a 6-year history of irritable snapping of the right wrist associated with numbness of the ipsilateral middle finger. At surgery we found that the median nerve became caught on the lunate osteochondroma while the wrist was extended and slipped over it when the wrist was flexed rapidly, thereby causing a snapping phenomenon. The symptoms disappeared completely after the protruding lesion was excised. Several cases of solitary carpal osteochondroma have been reported previously. (J Hand Surg 2005;30A:693– 695. Copyright © 2005 by the American Society for Surgery of the Hand.) Key words: Carpal bone, lunate osteochondroma, median nerve, snapping wrist.
A solitary osteochondroma of the carpal bones is very rare. A review of the literature showed a few cases in the scaphoid,1– 6 1 in the capitate,7 and 1 in the trapezium.8
Case Report A 16-year-old boy had a 6-year history of irritable snapping in the right wrist associated with numbness of the ipsilateral middle finger. No previous event of trauma was noted. The symptoms occurred on quick flexion of the extended wrist such as when shooting a basketball. He was referred to our outpatient clinic in November 2003. Physical examination showed a mass measuring approximately 2.5 cm in diameter on the palmar aspect of the wrist. A Semmes-Weinstein monofilament test showed diminished light-touch sensation From the Department of Orthopaedic Surgery, Saiseikai Utsunomiya Hospital, Utsunomiya, Tochigi, Japan. Received for publication February 1, 2005; accepted in revised form April 21, 2005. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Corresponding author: Takehiko Takagi, MD, Department of Orthopaedic Surgery, Saiseikai Utsunomiya Hospital, 911-1 Takebayashi-machi, Utsunomiya, Tochigi 321-0974, Japan; e-mail: [email protected]. Copyright © 2005 by the American Society for Surgery of the Hand 0363-5023/05/30A04-0007$30.00/0 doi:10.1016/j.jhsa.2005.05.001
on the right middle finger. Percussion of the mass elicited radiating numbness in the same digit. The thenar musculature did not appear atrophic and manual muscle testing of thumb opposition showed that its strength was equivalent to that of the other side. The range of wrist flexion was reduced to 40° as opposed to 80° on the unaffected side; however, no other motions including wrist extension, radial flexion, and ulnar flexion were reduced compared with the other side. Preoperative imaging showed a thick bony mass containing bone marrow broadly protruding from the volar aspect of the lunate (Figs. 1A, 2). No other bony lesions were identified on plain radiographs of the extremities including those of the opposite wrist. There was no family history of skeletal dysplasia. One month after referral the bony lesion was excised. After the proximal portion of the flexor retinaculum was divided the median nerve was found to be compressed by the bony protrusion from the ulnar side and by the flexor digitorum superficialis muscle belly from above. There was synovial proliferation around the nerve indicating chronic inflammation between the flexor tendons and the bony lesion. The incision of the joint capsule disclosed a bone tumor measuring approximately 1.5 by 1.0 cm that was covered by cartilage (Fig. 3). The lunate articular cartilage appeared almost completely normal. The The Journal of Hand Surgery
693
694
The Journal of Hand Surgery / Vol. 30A No. 4 July 2005
Figure 1. (A) Preoperative radiographs of the right wrist showing a dense bony lesion protruding from the palmar aspect of the lunate. (B) Radiographs 1 year after surgery showing that the bony lesion has been excised successfully (arrow).
snapping phenomenon was reproduced by the median nerve and the flexor tendons rubbing against the tip of the bone tumor when the extended wrist was flexed rapidly. The specimen from the excised lesion showed a cartilage cap overlying a layer of normal cancellous ossification, representing the typical pathologic findings of osteochondroma. The surface of the exposed cancellous bone was smoothed with a bone file and we expected fibrocartilaginous regeneration over the surface to occur. Both the snapping and numbness disappeared completely and they have not recurred more than 1 year after surgery. The range of wrist flexion increased to 75°. Postoperative plain
radiographs of the affected wrist showed that the bone tumor was excised successfully (Fig. 1B).
Discussion Solitary osteochondroma is the most common primary bone tumor; however, it rarely develops in the carpal bones. There have been reports of a few cases involving the scaphoid,1– 6 1 in the capitate,7 and 1 in the trapezium.8 Snapping wrist is a rare phenomenon that has been reported only occasionally since Marti9 first described the condition in 1960. Snapping phenomenon involving
Figure 2. Computed tomography scans showing that the bony lesion contains bone marrow (arrow). Left, sagittal view; right, axial view. C, capitate; L, lunate; R, radius; S, scaphoid; U, ulna.
Takagi, Matsumura, and Shiraishi / Lunate Osteochondroma With Snapping Wrist
695
usually occurred while the patient was shooting a basketball. The snapping phenomenon may be characteristic of the lunate osteochondroma located at the center of the carpus.
References
Figure 3. Intraoperative photograph taken with the joint capsule held open showing that the bone tumor measuring 1.5 by 1.0 cm is covered by a so-called cartilage cap (arrow).
the wrist joint may occur during finger, wrist, or forearm motions.10 In the present case the snapping phenomenon was reproduced during surgery by rubbing of the median nerve against the protruding bone tumor when the extended wrist was flexed rapidly. This mechanism of snapping can be attributed to a movement that
1. Harris NJ, Bell MJ. Bilateral scaphoid exostoses. J Hand Surg 1995;20B:745. 2. Medlar RC, Sprague HH. Osteochondroma of the carpal scaphoid. J Hand Surg 1979;4:150 –151. 3. Rimmer SG, Bhoora IG, Hooper G. Scaphoid exostosis and radio-carpal osteoarthrosis. J Hand Surg 1995;20B:741–744. 4. Spinner RJ, Spinner M. Superficial radial nerve compression due to a scaphoid exostosis. J Hand Surg 1996;21B:781– 782. 5. Stahl S, Rayek S. Scaphoid osteochondroma with scapholunate dissociation—a case report. Hand Surg 2000;5:73–75. 6. van Alphen JC, te Slaa RL, Eulderink F, Obermann WR. Solitary osteochondroma of the scaphoid: a case report. J Hand Surg 1996;21A:423– 425. 7. Malhotra R, Maheshwari J, Dinda AK. A solitary osteochondroma of the capitate bone: a case report. J Hand Surg 1992;17A:1082–1083. 8. Heiple KG. Carpal osteochondroma. J Bone Joint Surg 1961; 43A:861– 864. 9. Marti T. [Snapping wrist and carpal tunnel syndrome.] Sci Prog 1960;90:986 –988. 10. Ogino T, Kato H, Ohshio I. Trigger wrist induced by finger movement. Pathogenesis and differential diagnosis. Handchir Mikrochir Plast Chir 1994;26:3– 6.