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Ultrasound visualization of central slip injuries of the finger extensor mechanism1
Ultrasound Visualization of Central Slip Injuries of the Finger Extensor Mechanism Edward Westerheide, MD, Joseph M. Failla, MD, Marnix van Holsbeeck, MD, Ruth Ceulemans, MD, Detroit, MI
Purpose: To evaluate the ability of ultrasound to detect a central tear of the finger extensor tendon mechanism. Methods: Twelve fresh-frozen and thawed cadaver fingers were used. All fingers had a midradial incision with exposure of the extensor mechanism over the proximal interphalangeal joint. Six fingers had a sharp transection of the central slip. The other 6 fingers were used as sham dissection controls. All fingers had the exposure closed by suture and then were examined by a musculoskeletal ultrasonographer. Results: All 12 fingers were identified correctly as either sham controls with intact central slips or as injury models that had a transected central slip. Thus there was a sensitivity of 100% a specificity of 100%, and a positive predictive value of 1.000, which were statistically significant. Conclusions: Diagnostic ultrasound is a very accurate noninvasive study that can identify central slip injuries in the extensor mechanism of the finger. We recommend that clinically suspected cases of boutonniere injury be scanned by high-frequency ultrasound to confirm the diagnosis and allow either early initiation of splinting or eliminate the need for prolonged splinting required for this injury. (J Hand Surg 2003;28A:1009 –1013. Copyright © 2003 by the American Society for Surgery of the Hand.) Key words: Ultrasound, injury, central slip, extensor mechanism.
Boutonniere deformity results from undetected and unsplinted central slip ruptures in the extensor mechanism of the finger. The acute injury is difficult to diagnose because only dorsal proximal interphalangeal (PIP) joint swelling and pain may be present
From the Department of Orthopaedic Surgery and the Department of Musculoskeletal Radiology, Henry Ford Hospital, Detroit, MI. Received for publication June 24, 2003; accepted in revised form August 11, 2003. No benefits in any form have been received or will be received by a commercial party related directly or indirectly to the subject of this article. Reprint requests. Joseph M. Failla, MD, Head, Division of Hand Surgery, Department of Orthopaedic Surgery, Henry Ford Hospital, Center for Athletic Medicine, 6525 Second Ave, Detroit, MI 48202. Copyright © 2003 by the American Society for Surgery of the Hand 0363-5023/03/28A06-0018$30.00/0 doi:10.1016/S0363-5023(03)00427-1
early without an extensor lag. Once established, this deformity is very difficult to correct either by splinting or by surgery, is not tolerated well by patients, and leads to a high level of dissatisfaction and disability.1 When this lesion is accurately diagnosed acutely, the PIP joint splinted in extension and the distal interphalangeal (DIP) joint left free for active flexion, the boutonniere deformity along with its associated morbidity can be prevented. The key to preventing boutonniere deformities is early detection of central slip injuries and application of postinjury extension splinting. Several clinical tests have been devised to diagnose these injuries acutely. These include loss of PIP extensor tenodesis with passive metacarpophalangeal (MCP) joint flexion,1 weak active PIP extension,2 an active extensor lag despite extensor tenodesis by The Journal of Hand Surgery
1009
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The Journal of Hand Surgery / Vol. 28A No. 6 November 2003
Figure 1. Cadaver finger dissection of intact extensor mechanism, with central tendon isolated over an 18-gauge needle. (Proximal is to the right and distal is to the left.)
MCP joint and wrist flexion,3 and difficulty of DIP joint passive flexion while holding the PIP joint extended. These tests may be difficult to perform with a very painful acutely injured finger. X-ray diagnosis by PIP joint arthrography showing a dorsal leak of dye has been described.3 A noninvasive diagnostic tool to supplement clinical tests, such as routine anteroposterior and lateral X-rays, would be helpful to allow accurate, early diagnosis of this injury acutely so that a splinting program could be established to allow the central slip to heal and thus prevent a boutonniere deformity. Diagnostic ultrasound has proven to be useful in the diagnosis of tendon pathology. Tears have been well documented in large tendons such as the rotator cuff, Achilles tendon, and posterior tibial tendon.4 – 6 Tears also have been shown in smaller tendinous structures, including the continuity and position of smaller tendinous structures in the digit, such as a subluxating extensor tendon at the dorsal aspect of the MCP joint and the flexor digitorum profundus tendon insertion.7,8 Intact extensor tendon mechanism and flexor tendons have been shown successfully.9 Successful imaging of these other tendons led us to ask whether ultrasound could identify a torn extensor tendon mechanism in a finger.
passive range of motion. Fresh-frozen cadaver materials were selected because they most closely approximated the consistency of the soft tissues in vivo. Each finger was dissected by using a midradial incision extending from the proximal finger crease to the distal finger crease. The dorsal skin flap was elevated carefully off of the extensor mechanism and the central slip insertion was identified (Fig. 1). The lateral bands and dorsal PIP joint capsule were not disturbed. Six of these fingers had a sharp transection of the central slip overlying the PIP joint performed with a #15 scalpel blade (Fig. 2). The other 6 fingers were examined to be sure the central slip and extensor tendon were without any prior deformity and were left intact to be used as sham controls in the experiment. All 12 fingers then were sutured closed with an interrupted horizontal mattress technique (4-0 Ethibond; Ethicon Inc, Somerville, NJ).
Ultrasound Technique All 12 fingers were examined using real-time dynamic diagnostic ultrasound techniques. A compact/ linear array 5 to 10 MHz hockey stick scan head was used with an ultrasound machine (ATL3000; Advanced Technology Laboratories, Seattle, WA) highdensity imaging ultrasound machine to image all 12 fingers. The ultrasonographer, who was completely blinded to the type of extensor tendon dissection, attempted to determine whether a defect in the central slip region of the extensor mechanism was present. Longitudinal and transverse images were used both with flexion and extension at the PIP joint to determine whether a lesion was present. Images of each finger were made to show differences between intact and transsected central slips.
Materials and Methods Cadaver Preparation Four fresh-frozen cadaver forearms were obtained for this study. The index, middle, and ring fingers were used on each of these 4 specimens for a total of 12 finger specimens. Each finger was examined to ensure that no pre-existing deformity existed and that the MCP, PIP, and DIP joints had a full and fluid
Figure 2. Cadaver finger dissection with the central tendon transected, and proximal and distal tendon ends separated by skin hooks. (Proximal is to the right and distal is to the left.)
Westerheide et al / Ultrasound of the Injured Central Slip
Table 1. Ultrasound Results for Intact and Cut Specimens Central Slip Hand
Finger
Dissection
Ultrasound
1
Index Middle Ring Index Middle Ring Index Middle Ring Index Middle Ring
Intact Cut Intact Cut Intact Intact Intact Cut Cut Cut Intact Cut
Intact Cut Intact Cut Intact Intact Intact Cut Cut Cut Intact Cut
2
3
4
Scans were done in extension and flexion of the PIP joint. Extension made the central tendon less taut whereas flexion placed tension on the tendon. Normal tendons are echogenic and white in appearance when scanned parallel to the tendon fascicular bundles. When the tendon is scanned in joint flexion, however, the ultrasound is no longer parallel to the tendon fascicles, which causes tendon anisotropy and thus nonechogenicity (a black appearance). Central tendons were best visualized in flexion because this placed the intact central slip in tension and caused a gap in the cut central slip. Thus the central tendon appeared nonechogenic (black) on the scans. Results were analyzed statistically by the Fisher exact test. The purpose of this study design was to evaluate the ability of ultrasound to detect central tendon tears of the finger extensor mechanism.
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extending the PIP joint to show whether there was a discontinuity in the tendon.
Discussion Central slip ruptures often are missed at the initial presentation.1 Often the patient returns with a boutonniere deformity 2 to 3 weeks later. At that point the diagnosis is obvious but the treatment is more difficult because of the fixed deformity. Initiation of a splinting program at this point may allow the tendon to heal but often the tendon heals in a lengthened position and the deformity remains.7 Numerous surgical options exist but are very technically demanding and with potential complications of recurrence and stiffness. The best treatment by far is early diagnosis and initiation of a full-time splinting program. If the injury can be diagnosed and treated early, the tendon edges will be approximated and usually will heal without excessive lengthening at the tendon gap, palmar dislocation of the lateral bands, or transverse retinacular ligament contracture. The latter, if it occurs, can produce palmar translocation of the lateral bands that leads to flexion contracture of the PIP joint and hyperextension deformity of the DIP joint. Therefore the key to a good outcome after a central slip rupture is early diagnosis and initiation of a full-time splinting program. The clinical tests for early diagnosis of boutonniere injury are not always diagnostic. Results often are clouded because the tests rely on motion of a painful and swollen joint. PIP extensor lag and difficulty of active and passive flexion of the DIP joint may only appear weeks after
Results Ultrasound proved to be very sensitive and specific in the diagnoses of central slip ruptures. Every finger was identified correctly as either a sham control with an intact central slip or as an injury model with a transected central slip (Table 1). There was a sensitivity of 100%, a specificity of 100%, and a positive predictive value of 1.000, which were statistically significant (p ⫽ .002). In addition, the separation of the tendon edges in flexion could be determined as well as the area in which the lesion was created in terms of its distance from the insertion onto the middle phalanx. The intact central slips in the control group (Fig. 3) could be differentiated easily from the transected group (Fig. 4, 5) by slightly flexing and
Figure 3. Ultrasound of intact central tendon, which appears nonechogenic (black) (large white arrows) out to the insertion onto the middle phalanx base (small white arrows). M, middle phalanx dorsal cortex; P, proximal phalanx dorsal cortex. Note the smooth interface with the echogenic (white) subcutaneous tissue (large black arrow) dorsal to the central tendon and the echogenic dorsal cortex of the proximal phalanx shaft (small black arrow) and head palmar to the central tendon. (Proximal is to the right and distal is to the left.)
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The Journal of Hand Surgery / Vol. 28A No. 6 November 2003
Figure 4. Ultrasound of cut central slip in PIP extension. The proximal central tendon stump (black arrowhead) is seen as nonechogenic. It is wavy because it is no longer taut, and retracted proximal to the middle phalanx insertion site (small black arrow). M, middle phalanx; P, proximal phalanx. (Proximal is to the right and distal is to the left.)
injury. An accurate, relatively inexpensive diagnostic test would be helpful in distinguishing between central slip rupture and a simple sprain of a PIP joint if the clinical diagnosis is not clear. If there is a tear, immediate splinting is indicated to prevent development of the deformity. If there is not a tear, splinting is unnecessary and gentle range of motion exercises could be initiated to restore motion. This study documents the ability of ultrasound to diagnose central slip ruptures accurately in a cadaveric model. In this study ultrasound proved to be 100% sensitive and 100% specific in diagnosing central slip ruptures produced in cadaveric fingers. This cadaver study is limited by the fact that the fingers were not living and that the usual swelling and hemorrhage that would accompany these injuries was not present. The images obtained of the extensor mechanism of the finger and specifically the central slip region were very encouraging. Tremendous de-
tail could be seen including the size and location of the tear in relation to the insertion of the tendon into the proximal phalanx. A prospective in vivo study is needed to determine the true usefulness of ultrasound in diagnosing these acute injuries. If ultrasound proves to be as accurate in vivo as it has proven to be in vitro in this study it may dramatically change the outcome of this injury. Ultrasound may prove to be a valuable diagnostic test to evaluate acutely injured, painful, and swollen PIP joints to rule out central slip rupture. Rapid appropriate treatment then could be instituted based on whether or not the central slip is ruptured. Rapid definitive diagnosis undoubtedly would lead to a decreased rate of missed central slip tears. It would avoid the progression into rigid boutonniere deformities, which require serial casts or surgery. Early diagnosis for effective treatment
Figure 5. Ultrasound of cut central tendon in flexion. The tendon proximal stump is nonechogenic and is retracted to the proximal phalanx neck in this flexed specimen (arrow). P, proximal phalanx; M, middle phalanx. (Proximal is to the right and distal is to the left.)
Westerheide et al / Ultrasound of the Injured Central Slip
could prevent the morbidity associated with both the conservative and surgical treatment of this deformity.
References 1. Elson RA. Rupture of the central slip of the extensor hood of the finger. A test for early diagnosis. J Bone Joint Surg 1986;68B:229 –231. 2. Smith PJ, Ross DA. The central slip tenodesis test for early diagnosis of potential boutonniere deformities. J Hand Surg 1994;19B:88 –90. 3. Carducci AT. Potential boutonniere deformity its recognition and treatment. Orthop Rev 1981;10:121–123. 4. Middleton WD, Reinus WR, Totty WG, Melson CL, Murphy WA. Ultrasonographic evaluation of the rotator cuff and biceps tendons. J Bone Joint Surg 1986;68A:440 – 450.
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5. Karjalainen PT, Ahovuo J, Pihlajama¨ ki HK, Soila K, Aronen HJ. Postoperative MR imaging and ultrasonography of surgically repaired Achilles tendon ruptures. Acta Radiol 1996;37: 639 – 646. 6. Hsu T-C, Wang C-L, Wang T-G, Chiang I-P, Hsieh F-J. Ultrasonographic examination of the posterior tibial tendon. Foot Ankle Int 1997;18:34 –38. 7. Failla JM. Tendon injuries of the wrist and hand. In: Baratz ME, Watson AD, Imbriglia JE, eds. Orthopaedic surgery. The essentials. New York: Thieme Medical Publishers, 1999:405– 422. 8. Corduff N, Jones R, Ball J. The role of ultrasound in the management of zone 1 flexor tendon injuries. J Hand Surg 1994;19B:76 – 80. 9. McGeorge DD, McGeorge S. Diagnostic medical ultrasound in the management of hand injuries. J Hand Surg 1990;15B: 256 –261.
Purpose: To evaluate the ability of ultrasound to detect a central tear of the finger extensor tendon mechanism. Methods: Twelve fresh-frozen and thawed cadaver fingers were used. All fingers had a midradial incision with exposure of the extensor mechanism over the proximal interphalangeal joint. Six fingers had a sharp transection of the central slip. The other 6 fingers were used as sham dissection controls. All fingers had the exposure closed by suture and then were examined by a musculoskeletal ultrasonographer. Results: All 12 fingers were identified correctly as either sham controls with intact central slips or as injury models that had a transected central slip. Thus there was a sensitivity of 100% a specificity of 100%, and a positive predictive value of 1.000, which were statistically significant. Conclusions: Diagnostic ultrasound is a very accurate noninvasive study that can identify central slip injuries in the extensor mechanism of the finger. We recommend that clinically suspected cases of boutonniere injury be scanned by high-frequency ultrasound to confirm the diagnosis and allow either early initiation of splinting or eliminate the need for prolonged splinting required for this injury. (J Hand Surg 2003;28A:1009 –1013. Copyright © 2003 by the American Society for Surgery of the Hand.) Key words: Ultrasound, injury, central slip, extensor mechanism.
Boutonniere deformity results from undetected and unsplinted central slip ruptures in the extensor mechanism of the finger. The acute injury is difficult to diagnose because only dorsal proximal interphalangeal (PIP) joint swelling and pain may be present
From the Department of Orthopaedic Surgery and the Department of Musculoskeletal Radiology, Henry Ford Hospital, Detroit, MI. Received for publication June 24, 2003; accepted in revised form August 11, 2003. No benefits in any form have been received or will be received by a commercial party related directly or indirectly to the subject of this article. Reprint requests. Joseph M. Failla, MD, Head, Division of Hand Surgery, Department of Orthopaedic Surgery, Henry Ford Hospital, Center for Athletic Medicine, 6525 Second Ave, Detroit, MI 48202. Copyright © 2003 by the American Society for Surgery of the Hand 0363-5023/03/28A06-0018$30.00/0 doi:10.1016/S0363-5023(03)00427-1
early without an extensor lag. Once established, this deformity is very difficult to correct either by splinting or by surgery, is not tolerated well by patients, and leads to a high level of dissatisfaction and disability.1 When this lesion is accurately diagnosed acutely, the PIP joint splinted in extension and the distal interphalangeal (DIP) joint left free for active flexion, the boutonniere deformity along with its associated morbidity can be prevented. The key to preventing boutonniere deformities is early detection of central slip injuries and application of postinjury extension splinting. Several clinical tests have been devised to diagnose these injuries acutely. These include loss of PIP extensor tenodesis with passive metacarpophalangeal (MCP) joint flexion,1 weak active PIP extension,2 an active extensor lag despite extensor tenodesis by The Journal of Hand Surgery
1009
1010
The Journal of Hand Surgery / Vol. 28A No. 6 November 2003
Figure 1. Cadaver finger dissection of intact extensor mechanism, with central tendon isolated over an 18-gauge needle. (Proximal is to the right and distal is to the left.)
MCP joint and wrist flexion,3 and difficulty of DIP joint passive flexion while holding the PIP joint extended. These tests may be difficult to perform with a very painful acutely injured finger. X-ray diagnosis by PIP joint arthrography showing a dorsal leak of dye has been described.3 A noninvasive diagnostic tool to supplement clinical tests, such as routine anteroposterior and lateral X-rays, would be helpful to allow accurate, early diagnosis of this injury acutely so that a splinting program could be established to allow the central slip to heal and thus prevent a boutonniere deformity. Diagnostic ultrasound has proven to be useful in the diagnosis of tendon pathology. Tears have been well documented in large tendons such as the rotator cuff, Achilles tendon, and posterior tibial tendon.4 – 6 Tears also have been shown in smaller tendinous structures, including the continuity and position of smaller tendinous structures in the digit, such as a subluxating extensor tendon at the dorsal aspect of the MCP joint and the flexor digitorum profundus tendon insertion.7,8 Intact extensor tendon mechanism and flexor tendons have been shown successfully.9 Successful imaging of these other tendons led us to ask whether ultrasound could identify a torn extensor tendon mechanism in a finger.
passive range of motion. Fresh-frozen cadaver materials were selected because they most closely approximated the consistency of the soft tissues in vivo. Each finger was dissected by using a midradial incision extending from the proximal finger crease to the distal finger crease. The dorsal skin flap was elevated carefully off of the extensor mechanism and the central slip insertion was identified (Fig. 1). The lateral bands and dorsal PIP joint capsule were not disturbed. Six of these fingers had a sharp transection of the central slip overlying the PIP joint performed with a #15 scalpel blade (Fig. 2). The other 6 fingers were examined to be sure the central slip and extensor tendon were without any prior deformity and were left intact to be used as sham controls in the experiment. All 12 fingers then were sutured closed with an interrupted horizontal mattress technique (4-0 Ethibond; Ethicon Inc, Somerville, NJ).
Ultrasound Technique All 12 fingers were examined using real-time dynamic diagnostic ultrasound techniques. A compact/ linear array 5 to 10 MHz hockey stick scan head was used with an ultrasound machine (ATL3000; Advanced Technology Laboratories, Seattle, WA) highdensity imaging ultrasound machine to image all 12 fingers. The ultrasonographer, who was completely blinded to the type of extensor tendon dissection, attempted to determine whether a defect in the central slip region of the extensor mechanism was present. Longitudinal and transverse images were used both with flexion and extension at the PIP joint to determine whether a lesion was present. Images of each finger were made to show differences between intact and transsected central slips.
Materials and Methods Cadaver Preparation Four fresh-frozen cadaver forearms were obtained for this study. The index, middle, and ring fingers were used on each of these 4 specimens for a total of 12 finger specimens. Each finger was examined to ensure that no pre-existing deformity existed and that the MCP, PIP, and DIP joints had a full and fluid
Figure 2. Cadaver finger dissection with the central tendon transected, and proximal and distal tendon ends separated by skin hooks. (Proximal is to the right and distal is to the left.)
Westerheide et al / Ultrasound of the Injured Central Slip
Table 1. Ultrasound Results for Intact and Cut Specimens Central Slip Hand
Finger
Dissection
Ultrasound
1
Index Middle Ring Index Middle Ring Index Middle Ring Index Middle Ring
Intact Cut Intact Cut Intact Intact Intact Cut Cut Cut Intact Cut
Intact Cut Intact Cut Intact Intact Intact Cut Cut Cut Intact Cut
2
3
4
Scans were done in extension and flexion of the PIP joint. Extension made the central tendon less taut whereas flexion placed tension on the tendon. Normal tendons are echogenic and white in appearance when scanned parallel to the tendon fascicular bundles. When the tendon is scanned in joint flexion, however, the ultrasound is no longer parallel to the tendon fascicles, which causes tendon anisotropy and thus nonechogenicity (a black appearance). Central tendons were best visualized in flexion because this placed the intact central slip in tension and caused a gap in the cut central slip. Thus the central tendon appeared nonechogenic (black) on the scans. Results were analyzed statistically by the Fisher exact test. The purpose of this study design was to evaluate the ability of ultrasound to detect central tendon tears of the finger extensor mechanism.
1011
extending the PIP joint to show whether there was a discontinuity in the tendon.
Discussion Central slip ruptures often are missed at the initial presentation.1 Often the patient returns with a boutonniere deformity 2 to 3 weeks later. At that point the diagnosis is obvious but the treatment is more difficult because of the fixed deformity. Initiation of a splinting program at this point may allow the tendon to heal but often the tendon heals in a lengthened position and the deformity remains.7 Numerous surgical options exist but are very technically demanding and with potential complications of recurrence and stiffness. The best treatment by far is early diagnosis and initiation of a full-time splinting program. If the injury can be diagnosed and treated early, the tendon edges will be approximated and usually will heal without excessive lengthening at the tendon gap, palmar dislocation of the lateral bands, or transverse retinacular ligament contracture. The latter, if it occurs, can produce palmar translocation of the lateral bands that leads to flexion contracture of the PIP joint and hyperextension deformity of the DIP joint. Therefore the key to a good outcome after a central slip rupture is early diagnosis and initiation of a full-time splinting program. The clinical tests for early diagnosis of boutonniere injury are not always diagnostic. Results often are clouded because the tests rely on motion of a painful and swollen joint. PIP extensor lag and difficulty of active and passive flexion of the DIP joint may only appear weeks after
Results Ultrasound proved to be very sensitive and specific in the diagnoses of central slip ruptures. Every finger was identified correctly as either a sham control with an intact central slip or as an injury model with a transected central slip (Table 1). There was a sensitivity of 100%, a specificity of 100%, and a positive predictive value of 1.000, which were statistically significant (p ⫽ .002). In addition, the separation of the tendon edges in flexion could be determined as well as the area in which the lesion was created in terms of its distance from the insertion onto the middle phalanx. The intact central slips in the control group (Fig. 3) could be differentiated easily from the transected group (Fig. 4, 5) by slightly flexing and
Figure 3. Ultrasound of intact central tendon, which appears nonechogenic (black) (large white arrows) out to the insertion onto the middle phalanx base (small white arrows). M, middle phalanx dorsal cortex; P, proximal phalanx dorsal cortex. Note the smooth interface with the echogenic (white) subcutaneous tissue (large black arrow) dorsal to the central tendon and the echogenic dorsal cortex of the proximal phalanx shaft (small black arrow) and head palmar to the central tendon. (Proximal is to the right and distal is to the left.)
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The Journal of Hand Surgery / Vol. 28A No. 6 November 2003
Figure 4. Ultrasound of cut central slip in PIP extension. The proximal central tendon stump (black arrowhead) is seen as nonechogenic. It is wavy because it is no longer taut, and retracted proximal to the middle phalanx insertion site (small black arrow). M, middle phalanx; P, proximal phalanx. (Proximal is to the right and distal is to the left.)
injury. An accurate, relatively inexpensive diagnostic test would be helpful in distinguishing between central slip rupture and a simple sprain of a PIP joint if the clinical diagnosis is not clear. If there is a tear, immediate splinting is indicated to prevent development of the deformity. If there is not a tear, splinting is unnecessary and gentle range of motion exercises could be initiated to restore motion. This study documents the ability of ultrasound to diagnose central slip ruptures accurately in a cadaveric model. In this study ultrasound proved to be 100% sensitive and 100% specific in diagnosing central slip ruptures produced in cadaveric fingers. This cadaver study is limited by the fact that the fingers were not living and that the usual swelling and hemorrhage that would accompany these injuries was not present. The images obtained of the extensor mechanism of the finger and specifically the central slip region were very encouraging. Tremendous de-
tail could be seen including the size and location of the tear in relation to the insertion of the tendon into the proximal phalanx. A prospective in vivo study is needed to determine the true usefulness of ultrasound in diagnosing these acute injuries. If ultrasound proves to be as accurate in vivo as it has proven to be in vitro in this study it may dramatically change the outcome of this injury. Ultrasound may prove to be a valuable diagnostic test to evaluate acutely injured, painful, and swollen PIP joints to rule out central slip rupture. Rapid appropriate treatment then could be instituted based on whether or not the central slip is ruptured. Rapid definitive diagnosis undoubtedly would lead to a decreased rate of missed central slip tears. It would avoid the progression into rigid boutonniere deformities, which require serial casts or surgery. Early diagnosis for effective treatment
Figure 5. Ultrasound of cut central tendon in flexion. The tendon proximal stump is nonechogenic and is retracted to the proximal phalanx neck in this flexed specimen (arrow). P, proximal phalanx; M, middle phalanx. (Proximal is to the right and distal is to the left.)
Westerheide et al / Ultrasound of the Injured Central Slip
could prevent the morbidity associated with both the conservative and surgical treatment of this deformity.
References 1. Elson RA. Rupture of the central slip of the extensor hood of the finger. A test for early diagnosis. J Bone Joint Surg 1986;68B:229 –231. 2. Smith PJ, Ross DA. The central slip tenodesis test for early diagnosis of potential boutonniere deformities. J Hand Surg 1994;19B:88 –90. 3. Carducci AT. Potential boutonniere deformity its recognition and treatment. Orthop Rev 1981;10:121–123. 4. Middleton WD, Reinus WR, Totty WG, Melson CL, Murphy WA. Ultrasonographic evaluation of the rotator cuff and biceps tendons. J Bone Joint Surg 1986;68A:440 – 450.
1013
5. Karjalainen PT, Ahovuo J, Pihlajama¨ ki HK, Soila K, Aronen HJ. Postoperative MR imaging and ultrasonography of surgically repaired Achilles tendon ruptures. Acta Radiol 1996;37: 639 – 646. 6. Hsu T-C, Wang C-L, Wang T-G, Chiang I-P, Hsieh F-J. Ultrasonographic examination of the posterior tibial tendon. Foot Ankle Int 1997;18:34 –38. 7. Failla JM. Tendon injuries of the wrist and hand. In: Baratz ME, Watson AD, Imbriglia JE, eds. Orthopaedic surgery. The essentials. New York: Thieme Medical Publishers, 1999:405– 422. 8. Corduff N, Jones R, Ball J. The role of ultrasound in the management of zone 1 flexor tendon injuries. J Hand Surg 1994;19B:76 – 80. 9. McGeorge DD, McGeorge S. Diagnostic medical ultrasound in the management of hand injuries. J Hand Surg 1990;15B: 256 –261.