Radiographic Landmarks for Ideal Port Placement in Wrist Arthroscopy

Background The placement of wrist arthroscopy portals is traditionally performed using distances from anatomic landmarks. We sought to evaluate the safety of traditional portal placement and determine if radiographic landmarks could provide an additional method of identifying tendon intervals. Methods Six cadaveric specimens were used to evaluate the accuracy of portal placement based on anatomic and radiographic landmarks. Fluoroscopic images were used to document the location of previously described surface landmarks. Soft tissue was dissected away to identify the relationship between the transcutaneously placed portals and the extensor tendons. With soft tissue removed, tendon intervals were identified in relationship to anatomic carpal bone landmarks, and interval distances measured. Portals were then placed under radiographic imaging on the final three specimens and accuracy was examined by the removal of overlying soft tissue to confirm accurate interval placement Results The 3,4 portal was safely placed using only surface anatomic landmarks, however the 4,5 and midcarpal ulnar (MCU) portal sites were not consistently placed in the intended tendon interval, especially in larger wrists. Radiographic interval targets for the 3,4 portal were identified at the ulnar aspect of the scaphoid and the 4,5 portal at the ulnar one-third of the lunate. The radiographic site for the MCR was located at the inferior radial one-third of the capitate and the MCU portal was located at the radial aspect of the hamate. The 6R portal radiographic landmark is at the radial aspect of the triquetrum and 6U at the ulnar aspect of the triquetrum. Conclusion Portal placement in wrist arthroscopy based on anatomic landmarks alone can be unreliable in larger wrists. Radiographic imaging based on carpal bone landmarks provides an additional tool for consistent placement of portals in wrist arthroscopy and may limit unintended injury to extensor tendons. Level of Evidence This is a Level VI study.

Arthroscopic Anatomy of the TFCC with Relevance to Function and Pathology

Introduction The authors present a new comprehensive arthroscopic anatomical description of the fibrocartilage complex “TFCC” which is related to the current TFCC functional and pathological knowledge. Methods Our description of the TFCC is based on an arthroscopic view from the 3-4 portal as observed in more than 100 wrist arthroscopies in fresh cadavers and more than 1000 diagnostic and/or therapeutic wrist arthroscopies. Results TFCC is considered as a 3-D-3-part box-like structure (Reins, Wall and Disc). The first TFCC component (“R”) corresponds to 2 strong radio-ulnar ligamentous Reins, one dorsal (DRUL) and one palmar (PRUL). This “V-shaped” RUL reins diverge from the fovea and ulnar styloid to the volar and dorsal edges of the sigmoid notch. It is a main stabilizer of the DRUJ. The second TFCC component (“W”) is a continuous, radially concave Peripheral Capsular Wall attached and perpendicular to the RUL reins. It surrounds the ulnar aspect of the ulno-carpal interval while attaching to the RUL reins proximally and to the medial carpus distally. Along with the radiocarpal ligaments, the TFCC peripheral capsular wall contributes to the stability of the carpus with respect to the radius-ulna entity. This is especially true for the thick volar TFCC capsular wall. The third TFCC component (“D”) is the disc proper which is a static and dynamic shock absorber intercalated between the ulnar head and the medial proximal row in the coronal/sagittal planes and between the two strands of the RUL in the axial plane. Its pathology is influenced and related to the ulnar variance. Discussion This new arthroscopic description of the TFCC provides a comprehensive anatomical, functional ant pathological background for TFCC disorders analysis and treatment. Currently known disorders are included as “R 1,2,3,4”, “W 1, 2, 3, 4”, and “D 1, 2”. Combined TFCC disorders and further new pathology descriptions may be included in this open classification.

The Key Pinch Stress Radiograph to Evaluate Dorsal Subluxation in the Basilar Thumb Joint

The basilar thumb joint is the joint second most commonly affected by osteoarthritis (OA) in the hand. Evaluation of dorsal subluxation of the thumb during a functional task such as key pinch could help assess OA risk. The objectives of this study were to determine the best imaging angle for measuring thumb dorsal subluxation during key pinch and to compare subluxation to corresponding OA grades on the Eaton-Glickel, Outerbridge, and ICRS scales. Eleven cadavers cadveric forearm specimens were rigged to simulate key pinch. A mobile c-arm captured AP view images of the hand, and rotating in 5° increments toward the ulnar aspect of the arm up to 60°. Dorsal subluxation was measured on each image and compared to determine which angle captured maximum subluxation. The resulting best imaging angle was used for comparisons between dorsal subluxation of the thumb and OA grades for the basilar thumb joint. The max subluxation was in the AP view for most specimens. There was a significant correlation between subluxation and the Eaton-Glickel grade (p=0.003, R2 = 0.779), but not with either Outerbridge grades (p=0.8018) or ICRS grades (p=0.7001). Dorsal Our results indicate that dorsal thumb subluxation during key pinch should be measured in the A-P view of the forearm/handhand view. Dorsal thumb subluxation during key pinch had a significant correlation with the Eaton-Glickel radiographic measure of OA but not with more accurate visual classifications of OA.

Medial Sural Perforator “Nerve through Flap”: Anatomical Study and Clinical Application

Background: Nerve recovery after a complex trauma is affected by many factors and a poorly vascularized bed is often the cause of failure and perineural scar. Many techniques have been devised to avoid this problem and the possibility to transfer a nerve with a surrounding viable sliding tissue could help in this purpose; Methods: We performed an anatomic study on 8 injected specimens to investigate the possibility to raise a medial sural artery perforator (MSAP) flap including the sural nerve within its vascularized sheath; Results: In anatomic specimens, a visible direct nerve vascularization was present in 57% of legs (8 out of 14). In 43% a vascular network was visible in the fascia layer. There were no vascular anomalies. In one patient the MSAP flap was raised including the sural nerve with its proximal tibial and peroneal components within the deep sheath. The tibial and peroneal component of the sural nerve were anastomized independently with the common digital nerve of 4th and 5th fingers and with the collateral nerve for the ulnar aspect of the 5th. After 9 months, the patient showed an improving nerve function both clinically and electromyographically without any problem due to nerve adherence; Conclusions: Given the still debated advantage of a vascularized nerve graft versus a non-vascularized one, this flap could be useful in those cases of composite wounds with nerve lesions acting as a “nerve through flap”, in order to reduce nerve adherence with a viable surrounding gliding tissue.

Thumb Carpometacarpal Joint Pathoanatomy—A Computed Tomography-Based Study

Background Thumb carpometacarpal joint (CMCJ) osteoarthritis is common and can lead to significant morbidity making it a condition frequently treated by hand surgeons when initial conservative measures fail. The surrounding ligamentous structures are complex and important to maintain thumb CMCJ stability. Objectives The aim of this study was to review the normal and arthritic anatomy of the thumb CMCJ, focusing on morphology and position of osteophytes and the gap between metacarpal bases, and the effect of these on intermetacarpal ligament integrity. This may be the sole ligament suspending the first metacarpal following trapeziectomy and could determine the need for further stabilization during surgery, avoiding potential future failures. Methods Computed tomography (CT) scans of a normal cohort and those with arthritic changes who had undergone trapeziectomy following the scan were identified. The three-dimensional reconstructions were examined for osteophyte position on the saddle and the intermetacarpal distance. Results A total of 55 patients, 30 normal and 25 arthritic, were identified and studied. The most common anatomic position for osteophytes was the intermetacarpal ulnar aspect of the trapezium. The intermetacarpal distance increased by an average of 2.1 mm in the presence of the arthritic process. Conclusions The findings point to an increase in the intermetacarpal distance, and hence lengthening of the ligament with potential damage, possibly secondary to osteophyte formation and wear. Further prospective research is required to determine whether using preoperative CT scanning to define osteophyte position and measure the intermetacarpal distance would predict probable damage to the ligament, hence providing an indication for stabilization and reconstruction in trapeziectomy surgery. Level of Evidence This is a Level III, retrospective cohort study.

Single Incision, Dual Window Approach for a Comminuted Distal Radius Fracture

Introduction Complex distal radius fractures often involve a fragment of the volar-ulnar articular surface and the radial styloid. The volar ulnar corner of the distal radius is an important constraint to volar translation of the carpus and thus requires stable fixation to prevent wrist displacement. The traditional volar Henry approach often requires undue tension on the median nerve while retracting for access to the ulnar aspect of the radius. To protect the median nerve from iatrogenic injury and to improve exposure of the surgical site, we propose a single incision, dual window approach to the distal radius for complex bi-columnar fractures. Methods This technique combines the trans-Flexor Carpi Radialis (FCR) approach with a subcutaneous dissection to the ulnar aspect of the wrist. This window utilizes the interval between the ulnar neurovascular bundle and the carpal tunnel contents. Results This technique allows the surgeon to work through either window and thus visualize and directly fixate the various fracture fragments. We have treated complex articular distal radius fractures associated with ulnar communition with this novel technique and it has provided direct reduction with improved fragment access. The surgical technique, a case presentation and results are detailed in this report. Conclusion This case report has demonstrated that complex bi-columnar fractures of the distal radius can be effectively approached and fixated with a single incision dual window approach.

Does the location of short-arm cast univalve effect pressure of the three-point mould?

Purpose Forearm and distal radius fractures are among the most common fractures in children. Many fractures are definitively treated with closed reduction and casting, however, the risk for re-displacement is high (7% to 39%). Proper cast application and the three-point moulding technique are modifiable factors that improve the ability of a cast to maintain the fracture reduction. Many providers univalve the cast to accommodate swelling. This study describes how the location of the univalve cut impacts the pressure at three-point mould sites for a typical dorsally displaced distal radius fracture. Methods We placed nine force-sensing resistors on an arm model to collect pressure data at the three-point mould sites. Sensory inputs were sampled at 15 Hz. Cast padding and a three-point moulded short arm fibreglass cast was applied. The cast was then univalved on the dorsal, volar, radial or ulnar aspect. Pressure recordings were obtained throughout the procedure. Results A total of 24 casts were analyzed. Casts univalved in the sagittal plane (dorsal or volar surface) retained up to 16% more pressure across the three moulding sites compared with casts univalved in the coronal plane (radial or ulnar border). Conclusion Maintaining pressure at the three-point mould prevents loss of reduction at the fracture site. This study shows that univalving the cast dorsally or volarly results in less pressure loss at moulding sites. This should improve the chances of maintaining fracture reductions when compared with radial or ulnar cuts in the cast. Sagittal plane univalving of forearm casts is recommended.

Ulnar Subluxation of the Extensor Pollicis Longus Tendon as a Cause of Congenital Clasped Thumb: A Case Report

A 15-year-old male patient presented with difficulty extending his right thumb due to subluxation of the extensor pollicis longus (EPL) tendon. Physical examination showed that active motion of the thumb’s metacarpophalangeal (MP) joint was 76° in flexion and -58° in extension. During active extension, the EPL tendon shifted onto the ulnar aspect of the MP joint, and the extensor pollicis brevis (EPB) tendon shifted onto the central dorsal course of the MP joint. After repositioning by adducting the thumb into the palm to extend the MP joint (dynamic tenodesis effect), active extension of the MP joint increased to -12°. Corrective surgery was performed under local anesthesia and radial sensory nerve block. Following plication of the attenuated dorsal capsule and sagittal band between the EPB and EPL, we confirmed that the patient could flex and extend the thumb smoothly. One year postoperatively, the extension deficit of the MP joint had not recurred.

Modified Littler flap for sensory reconstruction of large thumb pulp defects

The Littler flap has been widely used to repair large pulp defects of the thumb; however, several complications have occurred frequently. In order to reduce these issues, the modified Littler flap innervated by the dorsal branch of the proper digital nerve and the proper digital nerve from the ulnar aspect of the middle finger or the radial aspect of the ring finger were devised in 16 consecutive cases. At the donor site, the defect of the proper digital nerve was repaired with a nerve graft from the proximal portion of the ipsilateral dorsal branch of the proper digital nerve. At the final follow-up, the scores for the static two-point discrimination test, Semmes–Weinstein monofilament test and total active motions in both recipient and donor fingers were nearly normal. This modified Littler flap provides a simple and reliable alternative for treatment of large defects of the thumb pulp with low donor-site morbidity. Level of Evidence: IV

Difficulty in Fixation of the Volar Lunate Facet Fragment in Distal Radius Fracture

Recent reports suggest the presence of a rare fracture type for which reduction and fixation cannot be achieved with volar locking plate (VLP). In particular, it is difficult to achieve reduction and fixation with volar lunate facet (VLF) fragments present on the volar ulnar aspect of the lunate facet, because of the anatomical structure and biomechanics in this region. Herein, we report two challenging cases of difficulty in fixation of the VLF fragment in distal radius fracture. For this fracture type, it is most important to identify the volar ulnar bone fragment before surgery; it may also be necessary to optimize distal placement of the VLP via a dual-window approach and to apply additional fixations, such as a small plate, anchor, and/or external fixation.