Table of Contents
Sagittal band rupture is an injury that causes rupture of the sagittal band, leading to subluxation of the extensor digitorum communis (EDC) tendon at the metacarpophalangeal (MCP) joint. The sagittal band encircles the EDC tendon at the MCP joint and functions as an important part of the extensor mechanism to stabilize the extensor tendon. It is a relatively uncommon injury, typically involving the long finger, that may occur with direct trauma in athletes or atraumatically in inflammatory or spontaneous cases; the mechanism may be acute or chronic. The common presentation involves pain and swelling at the MCP joint, visualization of extensor tendon subluxation during flexion, and inability to actively extend the MCP joint from a flexed position. The treatment for chronic rupture, as in this case, involves surgical repair followed by six weeks in a relative motion splint, in which the injured MCP joint is placed in greater extension relative to adjacent joints. The video here demonstrates direct repair of a chronic degenerative sagittal band rupture of the right ring finger.
Sagittal band rupture is an uncommon injury that involves rupture of the sagittal band, leading to subluxation of the extensor tendon at the metacarpophalangeal (MCP) joint. The sagittal band is a retinacular structure that encircles the extensor digitorum communis (EDC) tendon at the MCP joint via its superficial and deep layers. It has radial and ulnar components that attach to the palmar plate and transverse metacarpal ligaments.1 The sagittal band functions as an important part of the extensor mechanism to stabilize the extensor tendon and prevent bowstringing during hyperextension.1, 2
The mechanism of sagittal band rupture can occur traumatically or atraumatically and more commonly injures the radial sagittal band.3 Traumatic cases typically involve a direct blow to the MCP joint and is seen in boxers and martial artists, hence the term “boxer’s knuckle.”1 They can also occur under forced flexion or extension of the MCP joint or an open injury to the extensor mechanism. In atraumatic cases, ruptures can occur either spontaneously, via daily activities such as flicking a finger or crumpling paper, or in inflammatory settings such as osteoarthritis or rheumatoid arthritis.1, 2
The ruptures are classified into three types, as originally described by Rayan and Murray in 1994.3
- Type I: sagittal band rupture without tendon instability
- Type II: sagittal band rupture with tendon subluxation
- Type III: sagittal band rupture with tendon dislocation
The patient typically complains of pain and swelling at the MCP joint, most commonly of the long finger. They may also describe a sensation of snapping at the MCP joint.
On exam, subluxation or dislocation of the extensor tendon towards the edge of the metacarpal head or into the intermetacarpal recess upon MCP flexion may be visualized.1 The patient may have extensor lag or decreased flexion due to pain. To differentiate between sagittal band injury and extensor tendon dysfunction, the patient will be unable to actively extend the flexed MCP joint but will be able to maintain extension once passively placed in that position. In extensor tendon dysfunction, the patient will be able to actively extend the flexed MCP joint but unable to maintain extension.2 The patient may also have pseudo-triggering, secondary to crepitus occurring with subluxation, which is important to distinguish from true trigger finger to prevent unnecessary trigger release surgery.1
Imaging allows for confirmation of the diagnosis of sagittal band rupture. A series of hand radiographs in posterior-anterior, lateral, and oblique views are obtained to rule out fracture or dislocation.1 Additionally, a Brewerton view, an anterior-posterior picture of the MCP joint in 65° flexion in which the x-ray beam is directed 15° radially, may help to further characterize pathology in the joint.1, 2 Dynamic ultrasonography can provide visualization of tendon instability during flexion.4 Magnetic resonance (MR) imaging can confirm the rupture, and an MR arthrogram can show whether the joint capsule is intact, as rupture indicates poor prognosis for nonsurgical treatment.1
Most acute and closed injury cases can be treated nonoperatively with a relative motion splint that is placed as soon as possible, within three weeks after injury.2, 5, 6 The relative motion splint places the injured MCP joint in 15° to 20° of greater extension relative to adjacent digits, markedly reducing the amount of force placed on the tendon. The splint is worn for six weeks and full flexion and extension of digits as able in the splint is encouraged.6 Little to no additional therapy is required after this time and is efficacious in up to 71–84% of cases.1
Surgery is indicated for open injuries, chronic ruptures and those who fail nonoperative treatment. The general technique involves repair of the sagittal band and recentralization of the extensor tendon, performed under local anesthesia to assess for tendon stability.1, 2 There have been numerous methods reported in literature regarding strategies to augment the repair or stabilize the tendon when direct repair is insufficient. They primarily differ in what structure the proximal or distal EDC strip is routed around before being sutured to the intact EDC or joint capsule. These include the volar interosseous muscle, deep transverse metacarpal ligament, radial collateral ligament, and lumbrical tendon.1 Others have reported success with tendon graft pulleys, using the palmaris longus, juncturae tendinum, or extensor retinaculum routed directly through the metacarpal head.6 In chronic cases, release of tight ulnar structures or imbrication of the radial sagittal band may be required.2 There is considerable debate on whether the joint capsule should be repaired, as excessive repair may lead to decreased range of motion.1, 2
The goals of treatment, as alluded to above, are to ultimately minimize pain, restore function, and stabilize the extensor tendon for the patient. In the case here, the patient received surgery due to the chronic nature of the rupture, completed through direct repair which did not necessitate augmentation.
The repair is performed under local anesthesia in a wide-awake fashion. This allows for assessment of subluxation after sagittal band repair; however the surgery may be performed under other forms of anesthesia. The surgical site is marked out directly over the fourth metacarpal head, consistent with zone five of the extensor mechanism. Blunt dissection is performed until the extensor tendon and sagittal band is fully exposed. Once exposed, active motion by the patient confirms subluxation of extensor tendon, most commonly in the ulnar direction, which implies that the radial sagittal band is incompetent. In cases of acute ruptures, the ends of the sagittal band are readily approximated and repaired. In chronic ruptures, adequate tissues may not be available for primary repair. However, in this case, adequate tissue is confirmed for primary repair along the radial side. Additionally, in chronic cases, the competent side often becomes contracted and may require release to help with centering of the extensor mechanism, as performed here. For chronic ruptures, an imbrication of the extensor mechanism is required, completed via nonabsorbable 2-0 or 3-0 sutures in a figure-of-eight fashion.
Following surgery, the wound is washed, closed and dressed, with the hand placed in an Orthoplast yoke splint to be worn for the next six weeks. This is a hand-based splint that places the MP joint in extension relative to the other MP joints, to offload the repair while still allowing for tendon excursion to occur. However, both the DIP and PIP joints remain free, and the patient is allowed to move their fingers within the splint.
The case here consists of a repair of a chronic degenerative sagittal band rupture of the ring finger. Sagittal band ruptures represent a type of extensor tendon injury that result in subluxation of the extensor tendon over the metacarpal head with active flexion and extension. They can either be traumatic in origin or atraumatic, as in this case. Most acute cases are treated nonoperatively via splinting, with 71% or more achieving resolution of symptoms.2, 7 Chronic ruptures warrant surgery as in this case, with outcomes similar to or better than that of nonoperative treatment.1, 3, 8
The major complication for sagittal band rupture repair is recurrence; however, these are very rare with insufficient literature to describe these cases.1, 3, 8 In general, there remains dispute over the ideal method for repair, especially regarding augmentation methods of the sagittal band. One option is to transfer the ulnar-sided juncturae tendinum through the repaired radial sagittal band.1 Another option is to utilize the proximal or distal strips of the EDC tendon to route around the volar interosseous muscle, deep transverse metacarpal ligament, radial collateral ligament, or lumbrical tendon.1, 2 A third option involves creating tendon graft pulleys, via the palmaris longus, juncturae tendinum, or extensor retinaculum that is passed through the metacarpal head and dorsal to the tendon before being sutured to itself.6 All of these methods have been performed with excellent results.1, 2 There is also debate on management of joint capsule injury in cases of concomitant rupture. There have been studies demonstrating success and return to full activity with capsule repair while other studies warn against the potential for decreased MCP flexion.1, 2 Despite the variation in surgical technique, postoperative care is relatively consistent among surgeons. The relative motion splint, placed for four to six weeks, is superior to the splint that was previously used which placed the MCP joint in a neutral position.2
However, there is still a need for more robust studies and literature regarding ideal surgical technique and clarity on joint capsule repair. Studies with larger cohort sizes will allow for higher quality conclusions and lend towards standardization of care.
x1 3-0 nonabsorbable suture, Ethibond Excel
x1 orthoplast yoke splint
Nothing to disclose.
The patient referred to in this video article has given their informed consent to be filmed and is aware that information and images will be published online.
- Kleinhenz BP, Adams BD. Closed sagittal band injury of the metacarpophalangeal joint. J Am Acad of Ortho Surg. 2015;23(7):415-423. doi:10.5435/jaaos-d-13-00203.
- Sivakumar B, Graham DJ, Hile M, Lawson R. Sagittal band injuries: a review and modification of the classification system. J Hand Surg. 2022;47(1):69-77. doi:10.1016/j.jhsa.2021.09.011.
- Rayan GM, Murray D. Classification and treatment of closed sagittal band injuries. J Hand Surg. 1994;19(4):590-594. doi:10.1016/0363-5023(94)90261-5.
- Kichouh M, De Maeseneer M, Jager T, Marcelis S, Van Hedent E, De Mey J. The thickness of the sagittal bands in volunteers: high resolution ultrasound of the fingers. Surg Rad Anat. 2010;33(1):65-70. doi:10.1007/s00276-010-0693-6.
- Inoue G, Tamura Y. Dislocation of the extensor tendons over the metacarpophalangeal joints. J Hand Surg Am. 1996;21(3):464-469. doi:10.1016/S0363-5023(96)80364-9.
- Merritt WH. Relative motion splint: active motion after extensor tendon injury and repair. J Hand Surg. 2014;39(6):1187-1194. doi:10.1016/j.jhsa.2014.03.015.
- Roh YH, Hong SW, Gong HS, Baek GH. Prognostic factors for nonsurgically treated sagittal band injuries of the metacarpophalangeal joint. J Hand Surg. 2019;44(10):897.e1-897.e5. doi:10.1016/j.jhsa.2018.11.011.
- Ishizuki M, Sugihara T, Wakabayashi Y, Shirasaka R, Aoyama H. Stener-like lesions of collateral ligament ruptures of the metacarpophalangeal joint of the finger. J Ortho Sci. 2009;14(2):150-154. doi:10.1007/s00776-008-1301-z.
Cite this article
Wang J, Ilyas AM. Repair of a chronic degenerative sagittal band rupture of the right ring finger. J Med Insight. 2023;2023(331). doi:10.24296/jomi/331.
Table of Contents
- Mark Incision
- Injection of Local Anesthesia
Sagittal band ruptures represent an extensor tendon injury resulting in subluxation of the extensor tendon over the metacarpal head with active flexion and then active extension. Here, you can see the snapping tendon over the middle metacarpal head. Here is an intraoperative example of the same thing. The surgery is being performed under a local anesthesia. When the patient's finger is extended against resistance, you can see the subluxation of the extensor tendon. Sagittal band ruptures can either be traumatic in origin as in this case, or degenerative in origin as in the first example.
The video case being presented here consists of a chronic degenerative sagittal band rupture of the ring finger. The procedure is being performed under just a local anesthesia in a wide awake hand surgery fashion. An initial injection of the surgical site with lidocaine, with epinephrine, buffered with bicarbonate was applied in the preoperative area. The patient is now being prepared for surgery in the operating room.
The surgical site is being marked out directly over the metacarpal head. The surgical site is being augmented with some additional local anesthetic.
The incision is placed directly over the MP joint, consistent with a zone five of the extensor mechanism.
Blunt dissection is then performed down to the extensor mechanism until the extensor tendon and the sagittal band is fully exposed. Once adequately exposed, active motion by the patient confirms a subluxation of the extensor tendon in the ulnar direction upon active flexion followed by active extension. The ulnar subluxation of the extensor tendon implies that the radial sagittal band is incompetent as being examined here. In cases of acute ruptures, the ends of the sagittal band are readily reapproximated and repaired. In chronic ruptures, adequate tissue may not be available for primary repair and may require augmentation with either a graft or a transfer from the bordering digit sagittal band. In this case, adequate tissue is confirmed for primary repair along the radial side.
Prior to proceeding with the repair, the ulnar sagittal band is also examined. In chronic sagittal band rupture cases, the competent side often becomes contracted and may require release to help with the centering of the extensor mechanism as shown here. The release of the contracted side should be performed sharply from proximal to distal on a slow progressive basis until satisfied that adequate recentralization of the tendon has been achieved. Note, upon release of the contracted side, that active motion of the finger has already restored centralization of the extensor tendon even before repair or imbrication of the ruptured side.
Next, repair of the injured side is performed. Again, in the case of acute ruptures, a direct repair is possible. In the case of chronic ruptures, an imbrication of the extensor mechanism, as in this case, is required. A non-absorbable 2-0 or 3-0 suture is being used, in a figure-of-eight fashion. Two to three sutures typically will be adequate. In this case, two figure-of-eights using 3-0 Ethibond were used to repair the sagittal band.
Once repaired, the finger is taken through an active range of motion by the patient to confirm a centralized motion of the extensor tendon without subluxation.
Once satisfied with the repair, the wound is washed and closed.
Once closed, perhaps the most important part of the case is the splinting postoperatively. I recommend utilizing an Orthoplast yoke splint to be worn full-time for the next four to six weeks postoperatively. These splints are made from Orthoplast in the office by our therapist. However, exiting the operating room today, a temporary plaster yoke splint is being applied as demonstrated here. This is a hand-based splint that will place the MP joint in extension to offload the repair. The purpose of the yoke is to keep the operative MP joint extended relative to the other MP joints while still allowing for tendon excursion to occur. This is being performed here in the operating room, shown here by inserting rolled up Webril between the operative finger and the plaster, so that the MP joint is held in extension relative to the other fingers. However, both the DIP and PIP joints are free.
This splint is kept on as is until seen in the office. The patient is allowed to move their fingers within the splint as shown here. Once in the office, they are converted to a yoke splint. Once seen in the office, they are removed from their postoperative splint and placed in this Orthoplast yoke or relative motion splint as shown here. These images are from handsurgeryresources.com. I recommend motion within the splint for four to six weeks postoperatively. Thereafter, they can be weaned out of the splint.