UNASSIGNED: Extensor tendon subluxation or dislocation resulting from sagittal band rupture can be associated with snapping, catching, locking, pain, and swelling of the finger. Several etiologies were reported in the literature, with frequent mention of a traumatic rupture caused by a direct blow at the level of the metacarpophalangeal joint (MCPJ). The other causes of sagittal band injuries are degenerative disease, congenital infection, and rheumatoid arthritis. To our knowledge, we report the first case of spontaneous idiopathic bilateral sagittal band rupture.
UNASSIGNED: We, herein, present the case of a seronegative 29-year-old female who presented with pain and swelling in the dominant hand for 4 days.
UNASSIGNED: Upon examination, she was found to have bilateral dislocation of the extensor tendons at the level of the (MCPJ) of the third and fourth digits. Any underlying cause was excluded, and the diagnosis was confirmed with a dynamic ultrasound study.

A Stener-like lesion is defined as the interposition of the sagittal band between the torn collateral ligament of the metacarpophalangeal (MCP) joint of a finger and its origin or insertion. Owing to the rarity of this injury, standardized protocols on the diagnosis and care of these injuries are not currently available. PubMed Central and Google Scholar were searched for published studies from 1962 to 2022. Inclusion criteria admitted any injury of the MCP joints of any nonthumb fingers involving a torn collateral ligament with sagittal band injury that trapped the collateral ligament. Eight studies were ultimately included in our analysis and contained 11 cases of Stener-like lesions. Eight of the 11 cases presented radial collateral ligament injury to the ring and little fingers. All 11 cases presented showed that detailed physical examination was a primary step in diagnosis of these lesions. Metacarpophalangeal joint laxity was present in all cases reported. Imaging-aided diagnosis was used in majority of the cases presented and included arthrography, ultrasound, or magnetic resonance imaging. All cases presented in this review were managed surgically. Following surgical repair, a majority of authors opted to use immobilization techniques immediately postoperatively. As awareness of this injury pattern increases, a standardized treatment algorithm may develop.

Spontaneous extensor digitorum communis (EDC) tendon rupture is uncommon but easily confusing injury that lead to functional impairment. There is no any strict first-line treatment for nonrheumatoid EDC tendon rupture. We report a kidney transplant recipient with spontaneous rupture of the lateral expansion of the long-finger extensor tendon treated by wide awake surgery. Surgical repair with wide-awake local anesthesia was performed to realign the tendon for the patient. Three months following surgery, the patient obtained a full pain-free range of motion of the hand without recurrent dislocation.

The metacarpophalangeal (MCP) joint is surrounded by various structures critical to its stability and function. Though the ligamentous injury to the digits is common, rupture of the metacarpophalangeal collateral ligament and a sagittal band of the same finger is not well represented in the literature. We report a chronic case of a concurrent metacarpophalangeal collateral ligament and sagittal band injury. Though surgery would have been the most appropriate treatment soon after the injury, restrictions on elective procedures due to the COVID-19 pandemic precluded surgical treatment. The patient was alternatively treated with buddy tape, and a close follow-up was done. This is the first reported case of a concurrent metacarpophalangeal collateral ligament, and sagittal band injury successfully treated using nonoperative management.

A limitation of finger extension resulting from scarring of the juncturae tendinum (JT) is a rare condition. We report a patient with limitation in active extension of the metacarpophalangeal joint (MCPJ) of the ring finger due to a scarred JT in a 37-year-old man. Surgical exploration showed a hard, fixed and scarred JT in the third intermetacarpal space. After resection of the scarred JT, the patient achieved full range of active extension of the ring finger MCPJ. Scarring of the JT may decrease excursion of the extensor digitorum communis and must be considered as one of the differentials in patients with limitation in MCPJ extension. Level of Evidence: Level V (Therapeutic).

The sagittal bands are structurally important, aiding in the central alignment of the extensor tendons over the heads of each metacarpal. They resist the deviation of the tendon with flexion of the metacarpophalangeal (MCP) joint. Injury to the sagittal band can cause the extensor tendon to lose its alignment leading to pain, tendon subluxation, or dislocation. Generally, if these injuries are recognized and treated within 3 weeks of injury, they will not require surgery. The goal of surgery is to restore the anatomic alignment of the extensor tendon by either direct repair of the sagittal band or reconstruction.

We investigated the functional anatomy of the radial sagittal band and possible mechanisms involved in its spontaneous and traumatic rupture using seven cadaveric hands. First, the extensor tendon excursion and the change in angle between the sagittal bands and the tendon path were measured during metacarpophalangeal joint flexion. The radial bands were then divided in two different ways that mimicked spontaneous or traumatic rupture. We found no significant correlation between the extensor tendon excursion and the change in angle of the sagittal bands in the middle and ring fingers. Dislocation could occur when the radial sagittal band was only partially divided. This may explain why conservative treatment of tendon dislocation in the middle and ring fingers is feasible. Complete section of the sagittal bands in the little finger caused ulnar dislocation of the extensor tendon in only one out of seven hands.

Background: This systematic review assesses the current literature and reviews the clinical outcomes of treatment for sagittal band injuries and extensor tendon instability. Materials: A systematic search of MEDLINE, EMBASE, and the Cochrane databases was performed for English-language articles on the treatment of nonrheumatoid adult sagittal band injuries between 1969 and 2019. Two independent reviewers were involved in screening, data extraction, and critical appraisal. The level of evidence was assigned using the Sackett scale, and the methodological quality of the studies was evaluated using the Structured Effectiveness Quality Evaluation Scale (SEQES). Outcome measures were persistent pain, extensor lag, and recurrent tendon subluxation. Results: In all, 1653 abstracts were identified, with 43 articles reviewed in full text and 17 articles (429 treated digits) included in the final systematic review. There were 10 studies on surgical management, 3 on nonoperative management, and 4 on both. There were 4 retrospective case series and 13 retrospective case reports (Sackett level 4) with an average SEQES score of 15 (low quality). Studies on nonoperative management had on average more digits per study and higher SEQES scores (n = 27.7, SEQES = 19) compared with studies on surgical management (n = 11.8, SEQES = 13.8). Variability in reported outcome measures precluded meta-analysis. Conclusion: Qualitative synthesis of available literature suggests that acute sagittal band injuries can be successfully treated by splinting the injured digit in neutral or hyperextension. Patients with chronic injuries or those failing nonoperative management may benefit from surgical exploration. A lack of consistent outcome measures precluded comparison of surgical techniques.

The Elson technique is a rigid reconstruction method for a hypoplastic or absent sagittal band in the treatment of chronic extensor digitorum communis (EDC) tendon dislocation. We performed a modified procedure based on the Elson technique for reconstruction of the radial sagittal band in case involving the index finger. We investigated the postoperative outcomes of chronic EDC dislocation after treatment with the original and modified Elson technique.
We examined five fingers of five patients (2 males and 3 females) with a mean age of 41 years. The chronic EDC tendon dislocation was due to an old trauma, or a spontaneous or congenital condition involving the index in two, middle in two, and ring finger in one patient. Sagittal band reconstruction was performed using the modified Elson technique for the index finger and the original technique for the other fingers. The mean duration of postoperative follow-up was 58 months. Clinical findings such as pain and discomfort at metacarpophalangeal flexion associated with the tendon dislocation, range of motion (ROM), and disabilities of the arm, shoulder and hand were evaluated. We also examined postoperative recurrence and subjective patient evaluation.
All cases achieved pain-free stability of the EDC tendon with no recurrence, and full ROM was maintained at the latest examination after surgery. The postoperative subjective evaluation by the patients was \"very satisfied\" in four fingers and \"neutral\" in one finger.
We demonstrated our modified Elson technique for the treatment of chronic extensor tendon dislocation of the index finger.

It is a common belief that extension of the metacarpophalangeal (MCP) joint of the finger is achieved via the sagittal bands acting as a sling or lasso to attach the extensor tendon to the base of the proximal phalanx. The aim of this study was to test the hypotheses that (1) division of the sagittal bands reduces extension force or torque of the MCP joint, and (2) division of the extensor tendon distal to the sagittal band will not affect the extension force or torque of the MCP joint.
Ten cadaver limbs were secured to a jig to allow for testing of the extension force of the MCP joints of the index, middle, and ring fingers. A 1-kg load was applied to the forearm extensor digitorum communis tendon and the extension force was measured with the MCP joint positioned at 0° (neutral extension) and again at 45° flexion. These measurements were repeated after the sagittal bands were divided in 15 specimens; in the other 15 specimens, the extensor tendon was divided just distal to the sagittal bands.
After sagittal band division, extension force was similar in the 2 groups (0.11 N reduction after division with the MCP joints in neutral and 0.14 N in 45° flexion). There was significantly less extension force after division of the extensor tendon in both joint positions (0.95 N reduction after division in neutral extension and 0.66 N in 45° flexion).
The sagittal bands do not primarily extend the MCP as a sling or lasso. The extensor tendon continuation to the extensor hood and middle phalanx is the major extension motor. The MCP joint is extended by the torque generated by the extensor tendon passing the joint carrying a force and possessing an extension moment arm.
This principle should be correctly understood in the literature to ensure that clinical decisions related to injury and/or repair of the extensor tendon and sagittal bands are based on a sound understanding of their mechanics.