Peritendinitis of the Fourth Dorsal Compartment Due to Anomalous Extensor Indicis Proprius: A Case Report and Review of Anatomical Variations.

Anomalous Extensor Indicis Proprius Muscle

Spontaneous Rupture of the Extensor Pollicis Longus Tendon

BACKGROUNDThe extensor indicis proprius (EIP) tendon is a frequently used donor for a variety of tendon transfers, most commonly for reconstruction of the extensor pollicis longus (EPL). EIP is known to have frequent anatomic variants including split tendons and variations in tendon arrangement.AIMTo characterize the anatomy of the EIP at the level of the extensor retinaculum, where tendon harvest is often performed, and share our preferred technique for EIP to EPL transfer.METHODSTwenty-nine fresh-frozen cadaveric forearms without history of forearm or hand injury or surgery were dissected. Tendon circumference and relationship of the EIP and extensor digitorum communis to the index (EDCI) at the metacarpophalangeal (MCP) joint and the distal extensor retinaculum were recorded. Distance from the distal extensor retinaculum to the EIP myotendinous junction was measured.RESULTSEIP was ulnar to the EDCI in 96.5% of specimens (28/29) at the distal edge of the extensor retinaculum. In the remaining specimen, EIP was volar to EDCI. Tendon circumference at the distal extensor retinaculum averaged (9.3 mm ± 1.7 mm) for EDCI and 11.1 mm (± 2.7 mm) for EIP (P = 0.0010). The tendon circumference at the index MCP joint averaged 11.0 mm (± 1.7 mm) for EDCI and 10.6 mm (± 2.1 mm) for EIP (P = 0.33). EIP had a greater circumference in 76% (22/29) of specimens at the distal extensor retinaculum whereas EIP had a greater circumference in only 31% (9/29) of specimens at the MCP joint.CONCLUSIONThe EIP tendon is frequently ulnar to and greater in circumference than the EDCI at the distal extensor retinaculum, which can be taken into consideration for tendon transfers involving EIP.

Conséquences sur la force d’extension active de l’extenseur propre de l’index après prélèvement pour transfert tendineux : à propos de 19 cas cliniques

Variations in the extensor indicis proprius muscle in the Burmese population: implications for hand reconstructive surgery

Active extensor indicis proprius extension strength after its use as a tendon transfer: 19 cases

Extensor pollicis longus (EPL) tendon ruptures have been treated succesfully with the transfer of the extensor indicis proprius (EIP) tendon. Situations exist in which, due to intraoperative observations, another tendon transfer may be considered preferable to the standard EIP transfer method. To determine whether transfer of the extensor digitorum communis II (EDC II) tendon from the index finger to the EPL tendon, leaving the EIP tendon to the index finger intact, would serve as an equally efficient transfer and not adversely affect the function of the hand. Two patients who had the EDC II tendon transferred to the ruptured EPL tendon, and two patients who had the EIP tendon transferred, were retrospectively reviewed. In each transfer type, one patient had suffered an EPL tendon rupture after a Colles' fracture, and the other had rheumatoid arthritis. The rupture occurred on the non-dominant side in one patient in each transfer type. Each patient was examined and subjected to range of motion and power testing at least one year following surgery. All four patients showed a minimal extension lag with the lift off test, but there was no noticeable difference in range of motion, pinch grip and hand grip strength between the transfer types. Both EDC II transfer patients demonstrated an 8° to 15° loss of thumb interphalangeal joint flexion compared with the unoperated side; EIP transfer patients demonstrated less than a 5° loss. Three patients demonstrated a minor extension lag in the index finger and middle finger. Extension power of the thumb and index finger in all patients varied with wrist flexion and extension and ranged from 50% to 150% of the unoperated side. These case reports suggest that either index finger tendon may be successfully transferred in EPL tendon ruptures.

Prevalence of the extensor digitorum, extensor digiti minimi and extensor indicis tendons and their variations

To investigate the effectiveness of endoscopic-assisted median nerve decompression with one-stage extensor indicis proprius (EIP) tendon transfer for reconstruction of thumb abduction in patients with severe carpal tunnel syndrome (CTS). The clinical data of 12 patients with severe CTS who met the selection criteria between December 2019 and December 2024 were retrospectively analyzed. There were 2 males and 10 females with an average age of 55.4 years ranging from 35 to 67 years. The symptom duration of CTS was 12-120 months (mean, 48.7 months) and the thenar muscle atrophy duration was 6-48 months (mean, 13.4 months). The median nerve was released with the help of endoscope, and the EIP tendon was transferred to reconstruct the abduction function of the thumb. The operation time and complications were recorded. Two-point discrimination, palmar abduction angle of the thumb, radial abduction angle of the thumb, and pinch force of the thumb were measured and compared before operation and at last follow-up, and the effectiveness was evaluated by Kapandji score and Disabilities of the Arm, Shoulder and Hand (DASH) score. The satisfaction of the operation was evaluated at last follow-up. All surgeries were successfully completed with a mean operation time of 54 minutes (range, 45-68 minutes). All patients were followed up 6-50 months, with an average of 15.3 months. There was no complications such as wound infection, scar pain of wrist, or tendon rupture of transposition, and there were 3 cases of mild limitation of finger extension in the donor site of index finger. At last follow-up, two-point discrimination, palmar abduction angle of the thumb, radial abduction angle of the thumb, Kapandji score, and DASH score were significantly better than those before operation ( P<0.05), but there was no significant difference in thumb pinch force between pre- and post-operation ( P>0.05). The evaluation of surgical satisfaction showed that 7 cases were very satisfied and 5 cases were satisfied. The combination of endoscopic-assisted median nerve decompression and one-stage EIP tendon transfer effectively improves hand function and quality of life in patients with severe CTS by restoring thumb abduction and alleviating neurological symptoms.

Hypothesis Wrist magnetic resonance imaging (MRI) has shown excellent diagnostic accuracy in evaluating soft-tissue pathology of the wrist including ganglion cysts, ligament tears, and triangular fibrocartilage complex (TFCC) pathology. However, it is unclear how often MRI detects synovitis that is subsequently encountered during wrist arthroscopy and may be a source of pain for patients with symptoms unresponsive to conservative treatment. The aim of this study is to assess the diagnostic accuracy of conventional MRI in the detection of wrist synovitis observed intraoperatively with wrist arthroscopy. Materials and Methods A retrospective chart review was performed on 51 patients who underwent arthroscopy for chronic wrist pain and MRI confirmed wrist pathology that did not resolve with nonoperative treatment. Wrist arthroscopy was performed by three fellowship-trained hand surgeons. While the primary pathology like TFCC or scapholunate ligament tear was identified and treated arthroscopically, it was noted that many of the patients had concomitant synovitis observed arthroscopically that was not identified preoperatively on MRI. Therefore, the diagnosis of wrist synovitis on MRI scan was compared with the observed presence of synovitis at the time of wrist arthroscopy. Results of preoperative MRI without contrast were categorized as true positive, false positive, true negative, and false negative, based upon intraoperative arthroscopic findings. Results In total, 45/51 patients were confirmed to have dorsal and ulnar synovitis on wrist arthroscopy. MRI identified 16/51 patients as having synovitis. Of those 16 patients, 2 were false positives. Conclusion The results demonstrate that conventional MRI without contrast has poor diagnostic accuracy in detecting wrist synovitis. Patients with ligament or chondral pathology or no clearly identifiable pathology on MRI whose clinical symptoms persist despite conservative treatment may have underlying dorsal and ulnar wrist synovitis that is not detected on MRI. Wrist arthroscopy facilitates the identification and treatment of synovitis in patients with concomitant wrist pathology and pain refractory to nonoperative treatment. This study suggests that MRI may have a low sensitivity for identifying wrist synovitis when compared with wrist arthroscopy during the evaluation of patients presenting with wrist pain.

Understanding anatomical variations as well as normal anatomy of the muscles and tendons of the hand is vital for successful clinical evaluation and surgery. A number of extensor muscle and tendon variations have been reported in the literature, including duplication, triplication, and absence. We report a rare anatomical variation that includes bilateral absence of the extensor indicis (EI) muscles and bilateral duplication of the extensor digitorum (ED) tendon to the second digit in the forearm of an 83-year-old male cadaver during routine upper limbs dissection. In the present case, only three muscles were present in the deep compartment: extensor pollicis longus (EPL), extensor pollicis brevis (EPB), and abductor pollicis longus (APL) with bilateral absence of EI. The reported prevalence of bilateral absence of EI muscle and tendon ranges from 0.5% to 3.5%. The prevalence of an additional index tendon arising bilaterally from the ED muscle belly is 3.2% of the population. Extension of the index finger is governed by the actions of EI and ED. However, the four tendons of ED are linked to each other by juncturae tendinum, restricting independent extension of the digits in certain postures, e.g. when the hand is fisted. With fisted hand, EI controls extension of the index finger. Clinically, EI tendons are used for tendon reconstruction procedures to restore function to the hand and thumb after trauma or tendon rupture. This report highlights the importance of anticipating anatomical variations and conducting pre-operative evaluations to confirm the presence of EI when planning tendon transfer procedures.

Background: The wide-awake approach enables surgeons to adjust tendon transfer tension during active movement. Objective: To examine the proximity of the index finger to the thumb in the motor network of the brain during extensor indicis proprius (EIP) opponensplasty, performed under local anesthesia, for restoration of thumb opposition in patients with thenar paralysis caused by advanced carpal tunnel syndrome. Methods: Between April 2009 and October 2013, seven patients underwent wide-awake opponensplasty of the EIP in conjunction with carpal tunnel release. Under local anesthesia (lidocaine with epinephrine), the EIP tendon was routed subcutaneously, around the distal ulna and across the palm to the abductor pollicis brevis tendon. Results: Immediately after severing the EIP tendon over the metacarpophalangeal joint of the index finger, patients exhibited varying degrees of retraction of the proximal end of the EIP tendon into the dorsal subcutaneous space when asked to perform thumb opposition while maintaining active flexion of the index finger. All patients were able to perform palmar abduction of the thumb via the EIP following opponensplasty. Discussion: The intraoperative data suggest that single, individuated movements of the thumb opposition activate both the thenar muscle and the EIP. Additionally, these phenomena may be explained by activation of a pre-existing neural network, and overlap between the thumb and index finger in the motor cortex. Conclusion: Achievement of immediate thumb opposition without re-education suggests that the index finger and thumb are in close proximity in the motor network of the brain.

Rupture of Both the Abductor Pollicis Longus and Extensor Pollicis Brevis Tendons after Steroid Injection for de Quervain Tenosynovitis

We present a case of a patient who sustained a distal radius fracture and underwent volar plate fixation. Despite initial non-operative management, subsequent corrective osteotomy was required due to malunion. Eighteen months later, the patient presented with an inability to extend the thumb, leading to a diagnosis of extensor pollicis longus (EPL) tendon rupture. During the planned EPL tendon transfer procedure, an unexpected rupture of the extensor indicis proprius (EIP) tendon was discovered. The EIP tendon was then utilized as an interposition graft between the musculotendinous junction of the extensor indicis muscle and the EPL tendon to restore the function of EPL. This case highlights the potential for multiple tendon ruptures following distal radius fracture treatment, even in the absence of overt clinical signs. It emphasizes the importance of thorough preoperative assessment and intraoperative vigilance to identify and address such complications.

• MR or CT is advocated in the assessment of radiographically occult fractures. • The intrinsic ligaments of the wrist are better visualized at 3.0-T MRI than at 1.5-T MRI; however, MR or multidetector CT arthrography is the most sensitive at detecting intrinsic ligament and triangular fibrocartilage complex (TFCC) tears. • MR is more sensitive at detecting scapholunate ligament tears than lunotriquetral ligament tears. • TFCC tears can be divided into traumatic or degenerative tears, the latter being related to ulnar impaction syndrome. • Chronic wrist pain as a result of trauma may be secondary to scaphoid avascular necrosis, malunion, non-union, scapholunate advanced collapse and scaphoid non-union advanced collapse wrist or chronic regional pain syndrome. • Specific ulnar-sided wrist pain has its own unique causes that are optimally imaged with MR. • Doppler ultrasound and dynamic-enhanced MRI are the most sensitive imaging tools for diagnosing and monitoring synovitis in inflammatory arthropathies. • Most masses in the wrist and hand are benign and have typical imaging appearances. This article details the current imaging modalities utilized in the assessment of wrist pathology, with particular emphasis on recent developments and difficult areas. A stepwise approach for the assessment of wrist pathology in the context of clinical presentation will be discussed. The radiologist's role in the evaluation of wrist pain continues to evolve with the growing development of new techniques in order to evaluate with greater sensitivity the disorders affecting the complex joint and ligamentous structures of the wrist. The imaging strategy for wrist pathology begins with radiographs, with the use of further imaging such as ultrasound, CT, MRI and arthrography techniques if the diagnosis remains unclear.