Biomedical subjects

Steve K Lee

Publications and source records attributed to Steve K Lee.

6 recordsLinked to original sources

PubMed2006

Arthroscopic reduction-association of the scapholunate.

The reduction-association scapholunate (RASL) procedure for stabilization of the scapholunate joint is an alternative to soft-tissue procedures that do not maintain normal carpal alignment, despite reports of good symptomatic relief. The RASL procedure--indicated for patients with scapholunate instability or scapholunate dissociation without arthritis and, in selected cases, with stage 1 scapholunate advanced collapse of the wrist--can be performed arthroscopically. Radial midcarpal and 3-4 radiocarpal portals are used to excoriate and prepare the scapholunate joint surfaces. By use of 0.62'' K-wire joysticks in the lunate and distal pole of the scaphoid, the scaphoid undergoes dorsiflexion and supination while the lunate undergoes palmarflexion to achieve reduction. A .35'' guidewire is advanced through the scaphoid waist, across the scapholunate joint to the proximomedial corner of the lunate. Supplemental K-wire fixation, from the scaphoid to the capitatum and lunate to the radius, stabilizes the reduction for placement of a cannulated HBS screw (Orthosurgical Implants, Miami, FL) through a 1-2 portal, while reduction and positioning are confirmed arthroscopically. Arthroscopy facilitates anatomic reduction of the joint, as well as the critically important, precise placement of the cannulated HBS screw, by use of 3 portals rather than the traditional 2-incision approach.

Arthroscopy↗

PubMed2006

Carpal fractures excluding the scaphoid.

Although carpal fractures other than of the scaphoid are uncommon, vigilance in diagnosing these potentially serious fractures is paramount to early and effective treatment. Physical examination and standard plain radiographs may reveal only subtle findings. Use of special radiographic views and computed tomography may help elucidate the diagnosis. Treatment is particular to each fracture. Nondisplaced fractures should be treated nonoperatively. For intra-articular carpal bone fractures, virtually any amount of displacement is unacceptable and requires reduction and fixation. This article organizes current knowledge of these potentially difficult fractures, with a table of diagnosis and treatment guidelines.

Carpal Bones↗

PubMed2006

Wrist arthrofibrosis.

Wrist arthrofibrosis is a condition of decreased range of wrist motion due to intrinsic adhesions and extrinsic contracture. It is clinically characterized by restricted wrist range of motion, pain, swelling, and a plateau in improvement after at least 6 months of intensive physiotherapy. Other conditions must be excluded, such as articular incongruity, arthritis, spasticity, skin and subcutaneous scarring, and loose bodies. We have devised a classification system based on pathologic anatomic location, where Type I represents intrinsic adhesions, and Type II represents extrinsic contracture. The types are subdivided according to where the pathology is present. The operative approach should be wrist arthroscopy for Types IA (radiocarpal adhesions) and IB (midcarpal adhesions) where intraarticular adhesions are present. Types IC (distal radioulnar joint adhesions) and II C (distal radioulnar joint capsular contracture) are best approached in an open manner where dorsal and palmar capsulectomies of the distal radioulnar joint are performed. For Types IIA, B, and D (dorsal, palmar, and combination extrinsic contracture, respectively), both open and arthroscopic methods are described.

Adult↗

PubMed2005

Management of the distal radioulnar joint in rheumatoid arthritis.

The DRUJ frequently is involved in RA and can be a source of major disability. Nonoperative treatment consists of adequate hand/occupational therapy, judicious splinting, and pharmacologic management. If unacceptable pain and dysfunction persists or if there is tendon rupture, surgery is indicated. Surgical treatment ranges from debridement and soft tissue balancing if the joint is preserved to osseous procedures ranging from Darrach resection, Sauve-Kapandji procedure, hemiresection, to distal ulna replacement. Tendon ruptures usually require tendon transfers. If an osseous procedure is required, the authors prefer the Sauve-Kapandji procedure in the younger, active adult. Darrach distal ulna resection is recommended for the older, sedentary patient. For either procedure, if there is evidence of pre-existing radiocarpal instability, partial or total wrist arthrodesis or arthroplasty should bea concomitant procedure.

Arthritis, Rheumatoid↗

PubMed2005

Fixation of tendon grafts for collateral ligament reconstructions: a cadaveric biomechanical study.

PURPOSE: To compare the biomechanical properties of 4 methods of fixation of tendon grafts to bone as used for ligament reconstructions. METHODS: Thirty-two metacarpals were harvested from fresh-frozen cadavers and stripped of soft tissue. Flexor tendons were harvested from the same cadavers and cut into 2-mm-wide strips. Each tendon was fixed to a metacarpal head at the site of origin of a collateral ligament. Four different methods of fixation were tested. In group 1 the tendon was fixed to the bone with a 4.0-mm Arthrex bio-tenodesis interference screw (Arthrex, Inc., Naples, FL). In group 2 the tendon was passed through a bone tunnel and fixed with a 3.2-mm mini-Acutrak screw (Acumed, LLC, Hillsboro, OR) that was inserted in interference mode. In group 3 the tendon was passed through a bone tunnel and fixed with sutures tied over a polyethylene button. In group 4 the tendon was fixed with a mini-Mitek bone suture anchor (Mitek Worldwide, Norwood, MA). All specimens were clamped into a linear loading machine and loaded until failure. Statistical analysis was performed by 1-way analysis of variance testing. RESULTS: The differences in maximal tensile strength and stiffness were statistically significant when comparing any 2 groups. The Arthrex biotenodesis interference screw was the strongest and stiffest fixation method, followed by the Acutrak screw inserted in interference mode. Next was the suture tied over a button method. The mini-Mitek bone suture anchor was the weakest. CONCLUSIONS: Interference screw fixation of tendons to bone has statistically significant higher pullout strength and stiffness than 2 other commonly used fixation methods. The use of interference screws for fixation of tendon grafts to bone for hand ligament reconstructions is a promising new surgical technique.

Biomechanical Phenomena↗

PubMed2005

Thumb metacarpophalangeal ulnar collateral ligament injuries: a biomechanical simulation study of four static reconstructions.

PURPOSE: To determine the optimal tunnel placement positions for tendon graft reconstruction of chronic thumb metacarpophalangeal (MCP) ulnar collateral ligament injuries that would stabilize the joint while maintaining motion. METHODS: Four commonly used tunnel placement methods were simulated on a cadaveric model using fresh-frozen thumbs and a suture/screw construct. The methods were as follows: (1) triangular configuration with apex proximal, (2) triangular configuration with apex distal, (3) cruciate configuration, and (4) parallel configuration. Stability was tested by valgus loading at 0 degrees and 30 degrees , and range of motion was tested by loading the thumb tendons. Statistical analysis was performed by 1-way analysis of variance testing. RESULTS: Valgus load stability testing at 0 degrees and 30 degrees showed that all 4 reconstruction methods stabilized the MCP joint compared with the fully sectioned state. The amount of stability achieved was not significantly different between the 4 methods. Only the reconstruction method, however, with a triangular configuration with the apex proximal restored flexion/extension range of motion not significantly different from the intact state. The other 3 methods resulted in significantly decreased range of motion. CONCLUSIONS: The reconstruction tunnel positioning of triangular configuration with apex proximal stabilizes the thumb MCP joint while maintaining flexion/extension range of motion. We recommend this configuration for chronic MCP joint injuries in which the native ulnar collateral ligament is inadequate and tendon graft reconstruction is performed.

Biomechanical Phenomena↗