Introduction
Arthroscopy of the wrist is commonly used for the evaluation and treatment of multiple wrist disorders including chronic wrist pain, interosseous ligament tears, triangular fibrocartilage complex tears, ganglion cysts, and wrist synovitis. Arthroscopy is considered the gold standard for the diagnosis of intra-articular ligamentous injuries and is becoming more widely used as a visual aid during intra-articular fracture reduction and fixation and shortening osteotomies. A detailed understanding of wrist anatomy and biomechanics is essential to successful arthroscopy.
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Indications
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Diagnosis of wrist pain
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Synovitis and loose bodies
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Known or suspected scapholunate ligament (SLL) or lunotriquetral ligament (LTL) tears
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Triangular fibrocartilage complex (TFCC) tears
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Ganglion cysts
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Intra-articular distal radius fractures
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Scaphoid fractures
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Ulnocarpal impaction
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Common procedures performed
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Diagnostic arthroscopy
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Synovectomy, débridement, and removal of loose bodies
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TFC débridement or repair
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SLL or LTL repair or débridement
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Arthroscopic ganglionectomy
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Arthroscopically assisted distal radius and scaphoid fracture reduction
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Ulnar-shortening osteotomy
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Contraindications to wrist arthroscopy include
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Local skin infection
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Previous injury with significant scarring or derangement of normal anatomic landmarks
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Moderate-to-severe wrist arthritis preventing insertion of arthroscope
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Preoperative Considerations
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Preoperative workup
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A thorough history and physical examination of the wrist should be performed prior to surgery and preoperative wrist range of motion, grip strength, and a detailed neurovascular examination should be noted.
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Imaging modalities such as radiographs, MRI, CT, ultrasound, or fluoroscopic arthrogram should be used as indicated to aid in diagnosis.
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Selective diagnostic intra-articular injections may be used as a preoperative diagnostic modality.
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The patient should be counseled on the anticipated outcome or goal of the surgery, including the risks and benefits and the expected course of recovery.
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If a diagnostic arthroscopy is planned, the patient should give consent for any procedures that may be indicated by the intra-operative findings and should be made aware of the expected postoperative course, given each situation.
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Anesthesia
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Local, general, or regional anesthesia or any combination thereof
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A regional block such as an intrascalene or supraclavicular block preoperatively with administration of general anesthesia is usually preferred.
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Patient positioning ( Fig. 7-1 )
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Patient is placed supine on the operating table with the operative upper extremity extended onto an armboard at the patient’s shoulder level.
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A nonsterile tourniquet is applied to the patient’s brachium but not inflated, or a sterile tourniquet may be applied later in the surgery if conversion to an open procedure is planned or deemed necessary by arthroscopic findings.
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The patient is prepped and draped using standard technique.
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The surgeon stands at the patient’s head facing the dorsal aspect of the wrist and the patient’s feet. The monitor is set up at the patient’s feet facing the surgeon.
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The Mayo tray is placed on the armboard under the patient’s operative arm to provide a stable base.
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The traction tower is placed on the Mayo stand. The patient’s elbow is flexed to 90 degrees in neutral pronation. The volar aspect of the patient’s forearm should lie against the traction tower. Padding is applied as indicated.
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Two straps are used to secure the arm to the tower: one strap wraps under the Mayo stand and secures the patient’s brachium; the other strap secures the traction tower to the patient’s forearm.
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30 degrees of volar tilt is applied to the traction tower to place the wrist into a slightly flexed position.
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The tower is fitted with the traction gauge and the finger traps are applied (tip: if patient’s fingers slide out of the traps, a self-adhesive bandage or tape can be wrapped around the finger before applying the trap to prevent slipping). Typically the index and middle fingers are suspended for traction, but if particular attention is going to be paid to the ulnar side of the wrist, the ulnar fingers may be suspended also.
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The tower is adjusted to provide 15 lb of traction force across the wrist.
Figure 7-1
Patient positioning.
(From Chhabra AB. Wrist and hand. In Miller MD, Chhabra AB, Hurwitz S, et al. [eds]. Orthopaedic Surgical Approaches. Philadelphia, Elsevier, 2008; p 188.)
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Equipment
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Armboard attached to operating table.
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Mayo tray
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Traction tower
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Traction gauge
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Towels for padding
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Straps
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Finger traps
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Arthroscope
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Monitor and printer to document findings
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Probe
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Blunt trochar
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Shaver
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Set of arthroscopic graspers and biters
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18-Gauge needle for outflow
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Lactated Ringer solution or Normal Saline suspended from IV pole
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Relevant Anatomy
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Extensor tendon compartments ( Fig. 7-2 )
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1st: extensor pollicis brevis, abductor pollicis longus (EPB, APL)
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2nd: extensor carpi radialis brevis, extensor carpi radialis longus (ECRB, ECRL)
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3rd: extensor pollicis longus (EPL)
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4th: extensor digitorum communis, extensor indicis proprius (EDC, EIP)
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5th: extensor digiti minimi ( EDM)
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6th: extensor carpi ulnaris (ECU)
Figure 7-2
Extensor compartments.
(From Chhabra AB. Wrist and hand. In Miller MD, Chhabra AB, Hurwitz S, et al. [eds]. Orthopaedic Surgical Approaches. Philadelphia, Elsevier, 2008; p 156.)
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Radiocarpal joint ( Fig. 7-3 )
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Radius with scaphoid and lunate fossae
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Ulna and ulnar styloid
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Prestyloid recess
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Distal radioulnar joint and sigmoid notch
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Proximal carpal row: scaphoid, lunate, triquetrum (pisiform)
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The TFCC is located on the ulnar aspect of the wrist and stabilizes the distal radiioulnar joint (DRUJ). It is poorly vascularized centrally but has adequate peripheral blood flow. It is composed of
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Fibrocartilage disc
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Volar and dorsal distal radioulnar ligaments
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Meniscus homolog
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Volar ulnocarpal ligaments: ulnolunate and ulnotriquetral ligaments
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ECU tendon sub sheath
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Figure 7-3
Radiocarpal joint anatomy.
(Modified from Cooney WP, Linscheid RL, Dobyns JH. The Wrist: Diagnosis and Operative Treatment. St. Louis, C.V. Mosby, 1998.)
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Mid-carpal joint
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Distal carpal row: trapezium, trapezoid, capitate, hamate.
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Can visualize the distal scaphoid, lunate, and triquetrum of the proximal row
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Ligaments ( Fig. 7-4 )
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Interosseous
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Scapholuate ligament (SLL): C-shaped ligament which is thinner and weaker volarly and stronger and thicker dorsally.
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Lunotriquetral ligament (LTL)
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Extrinsic ligaments:
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Radioscaphoid ligament (RS)
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Radioscaphocapitate ligament (RSC)
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Long and short radiolunate ligaments (LRL, SRL)
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Radioscapholunate ligament (RSL, also known as ligament of Testut—contains neurovascular supply to the SLL and lunate; sometimes not considered a ligament because it is often found within loose connective tissue)
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Ulnolunate and ulnotriquetral ligaments (part of TFCC)
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Dorsal intercarpal ligament
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Dorsal radiocarpal ligament
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Figure 7-4
Ligaments.
(From Chhabra AB. Wrist and hand. In Miller MD, Chhabra AB, Hurwitz S, et al [eds]. Orthopaedic Surgical Approaches. Philadelphia, Elsevier, 2008; p 150. )
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Portal Placement ( Fig. 7-5 )
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All portals are named based on the bordering extensor compartments and are located such that important neurovascular and tendinous structures are protected. Although there are 12 portals that may be used, the most common portals are the 1-2, 3-4, 4-5, mid-carpal radial (MC-R), and mid-carpal ulnar (MC-U), 6U and 6R.
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3-4 portal
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Between the 3rd and 4th extensor compartments approximately 1 cm distal and ulnar to Lister’s tubercle in the “soft spot” of the radiocarpal joint.
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This is the first portal to be established for most procedures and is used for introduction of the arthroscope into the radiocarpal joint.
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4-5 portal
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Between the 4th and 5th extensor compartments at the level of the radiocarpal joint.
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Establish this portal under visualization from the 3-4 portal.
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This is the first instrument portal.
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6R portal
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Radial to the 6th extensor compartment between the EDM and ECU tendons at the level of the radiocarpal joint
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Establish under direct visualization from the 3-4 portal.
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Used for TFCC repairs.
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6U portal
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Ulnar (or volar) to the 6th extensor compartment
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Used for TFCC repairs
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Take caution to avoid injury to dorsal sensory branch of ulnar nerve
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1-2 portal
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Between the 1st and 2nd extensor compartments and radial to the 3rd extensor compartment
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Take caution to avoid injury to the radial artery in the anatomical snuffbox
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Midcarpal radial portal
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Approximately 1 cm distal to the 3-4 portal, bordered by the ECRB and the 4th extensor compartment at the level of the mid-carpal joint.
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Used as arthroscope portal for evaluation of the mid-carpal joint, scapholunate ligament, and lunotriquetral ligament.
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Mid-carpal ulnar portal
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Approximately 1 cm distal to the 4-5 portal between the 4th and 5th extensor compartments at the level of the mid-carpal joint
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Used as instrument portal when evaluating structures of the mid-carpal joint
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Other portals
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Distal radioulnar joint portal
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Working portal: Located just proximal to the DRUJ and the 4-5 working portal, bordered by the radius and ulna and the 4th and 5th extensor compartments
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Viewing portal: located more proximal than the working portal just ulnar to the 5th extensor compartment.
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Scaphoid-trapezium-trapezoid portal
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Located just ulnar to the 3rd extensor compartment and just radial of the ECRB insertion at the level of the distal pole of the scaphoid.
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Triquetrohamate portal
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Located just distal to the 6U portal between the insertion point of the ECU and the EDM at the level of the mid-carpal joint
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Volar radial (VR) portal
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A 2-cm longitudinal incision is made over the flexor carpi radialis (FCR) tendon. FCR is identified and retracted ulnarly.
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A needle is used to establish this portal under direct visualization from the 3-4 portal.
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Volar ulnar (VU) portal
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A 2-cm longitudinal incision is made over the FCU. FCU is identified and retracted ulnarly, thereby protecting the ulnar nerve.
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Develop an interval between the FCU and common flexor tendons.
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A needle is used to establish this portal under direct visualization from the 3-4 or 4-5 portal.
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