SciCombinator

Discover the most talked about and latest scientific content & concepts.

Journal: The Journal of hand surgery

166

PURPOSE: To compare the biomechanical and technical properties of flexor tendon repairs using a 4-strand cruciate FiberWire (FW) repair and a 2-strand multifilament stainless steel (MFSS) single cross-lock cable-crimp system. METHODS: Eight tests were conducted for each type of repair using cadaver hand flexor digitorum profundus tendons. We measured the required surgical exposure, repair time, and force of flexion (friction) with a custom motor system with an inline load cell and measured ultimate tensile strength (UTS) and 2-mm gap force on a servo-hydraulic testing machine. RESULTS: Repair time averaged less than 7 minutes for the 2-strand MFSS cable crimp repairs and 12 minutes for the FW repairs. The FW repair was performed with 2 cm of exposure and removal of the C-1 and A-3 pulleys. The C-1 and A-3 pulleys were retained in each of the MFSS cable crimp repairs with less than 1 cm of exposure. Following the FW repair, the average increase in friction was 89% compared with an average of 53% for the MFSS repairs. Six of the 8 MFSS specimens achieved the UTS before any gap had occurred, whereas all of the FW repairs had more than 2 mm of gap before the UTS, indicating that the MFSS was a stiffer repair. The average UTS appeared similar for both groups. CONCLUSIONS: We describe a 2-strand multifilament stainless steel single cross-lock cable crimp flexor repair system. In our studies of this cable crimp system, we found that surgical exposure, average repair times, and friction were reduced compared to the traditional 4-strand cruciate FW repair. While demonstrating these benefits, the crimp repair also produced a stiff construct and high UTS and 2-mm gap force. CLINICAL RELEVANCE: A cable crimp flexor tendon repair may offer an attractive alternative to current repair methods. The benefits may be important especially for flexor tendon repair in zone 2 or for the repair of multiple tendons.

Concepts: Knee, Force, Tensile strength, Steel, Titanium, Strength of materials, Flexor digitorum profundus muscle, Stainless steel

28

Restoration of stability and movements at the shoulder joint are the 2 most important goals in the management of brachial plexus injuries. The 2 nerves that are preferentially targeted for this purpose are the suprascapular (SSN) and the axillary (AXN) nerves. These nerve transfers have conventionally been performed by the anterior approach, but recently transfers performed by posterior incisions have been gaining popularity, by virtue of being selective and located close to the target muscles. Herein, we describe the technical details of spinal accessory nerve (SAN) to SSN and triceps branch to AXN for upper plexus injuries, both performed by the posterior approach.

Concepts: Cranial nerves, Brachial plexus, Suprascapular nerve, Trapezius muscle, Axillary nerve, Radial nerve, Accessory nerve

28

PURPOSE: To describe the origin and insertion of the radial collateral ligament (RCL) of the index metacarpophalangeal (MP) joint, relative to the MP joint line and other landmarks readily discernible intraoperatively. METHODS: We dissected 17 fresh-frozen human cadaveric index fingers. We removed all overlying soft tissue from the MP joint except for the proper RCL. We dissected the RCL from its original insertion under loupe magnification while concurrently marking the ligamentous origin and insertion points. We measured distances of these points in relation to the bony landmarks (dorsal, articular, and volar surfaces) using digital photo analysis. The same observer recorded all measurements to reduce systematic error. RESULTS: The center of the metacarpal attachment of the RCL was located 5.4 ± 1.1 mm from the dorsal border of the metacarpal, 8.0 ± 2.2mm from the volar border of the metacarpal, and 10.3 ± 3.2mm from the articular surface of the MP joint. The total width and height of the metacarpal origin site were 5.8 ± 1.6 and 6.4 ± 1.4 mm, respectively. The center of the proximal phalanx attachment of the RCL was located 6.8 ± 1.4 mm from the dorsal border of the proximal phalanx, 5.7 ± 0.9mm from the volar border of the proximal phalanx, and 4.4 ± 0.8mm from the articular surface of the MP joint. The total width and height of the phalangeal origin site were 5.0 ± 1.1 and 5.7 ± 0.9 mm, respectively. CONCLUSIONS: Our study defines the anatomic origin and insertion of the RCL of the index MP joint in relation to landmarks that are identifiable during surgery. CLINICAL RELEVANCE: We believe this information will be useful to surgeons when repairing or reconstructing the RCL, allowing for recreation of normal RCL anatomy.

Concepts: Skeletal system, Measurement, Joint, Anatomy, Joints, Ligament, Finger, Metacarpophalangeal joint

28

The aim of our study was to describe a dorsal distal radius vascularized bone graft pedicled on the posterior interosseous artery (PIA), and its clinical application in 2 cases of ulnar nonunion. We studied the surgical technique in 5 freshly injected cadavers. The 4th extensor compartment artery originates from the anastomotic arch between the posterior division of the anterior interosseous artery and the PIA and provides periosteal branches to supply the dorsal distal radius metaphysis. A 2-cm vascularized bone graft can be harvested from the radius, and dissection of the PIA enables a long pedicle with a wide arc of rotation able to reach the ulnar diaphysis. The approach is limited to the forearm and distal radius and has minimal donor morbidity.

Concepts: Surgery, Forearm, Median nerve, Pronator quadratus, Arteries of the upper limb, Common interosseous artery, Anterior interosseous artery, Posterior interosseous artery

28

We present our experience in using pulse oximetry as an aid in the diagnosis of thoracic outlet syndrome (TOS). Our attention was given to those symptomatic patients without objective confirmatory data on imaging or electrodiagnostic evaluation.

Concepts: Cardiology, Syndromes, Medical tests, Pulse oximetry

28

Regional anesthesia has become the preferred method of anesthesia for many upper extremity operations and generally results in decreased hospital stays, postoperative opioid requirement, and postoperative nausea. Complications of regional anesthesia are rarely reported in the literature, possibly because of limited anesthesiologist-patient follow-up. Three cases of suprascapular nerve palsy after ultrasound-guided supraclavicular nerve block for routine outpatient upper extremity surgery are reported. All cases occurred in men who originally presented with shoulder pain, which resolved with time, followed by weakness in the supraspinatus and infraspinatus, which improved over time but did not resolve. One case resulted in ipsilateral phrenic nerve palsy as well. A review of the literature on the subject accompanies the report of these 3 cases.

Concepts: Anesthesia, Opioid, Vomiting, Shoulder, Supraspinatus muscle, Infraspinatus muscle, Suprascapular nerve, Nerves of the head and neck

28

Previous studies have investigated the long-term outcomes of ulnar shortening osteotomy (USO) in the treatment of ulnocarpal abutment syndrome (UCA), but none have used arthroscopic assessments. The purpose of this study was to investigate the long-term clinical outcomes of USO with patient-based, arthroscopic, and radiographic assessments.

Concepts: Orthopedic surgery, Cultural studies

27

Endoscopic cubital tunnel release was originally described in 1989 by Tsai, and his technique has been modified by other surgeons including Mirza and Cobb. In 2006, Hoffmann and Siemionow described an endoscopic technique quite different from Tsai’s original description. Instead of working from the “inside out,” Hoffmann’s technique is performed through an incision similar to that which would be used for an in situ release of the ulnar nerve. The main difference being that the nerve can be explored and decompressed 10 cm proximal and distal to the arcuate ligament as the surgeon looks down on the nerve and the surrounding tissues while viewing the anatomy through a camera attached to a soft tissue endoscope that is inserted in the wound. The arcuate (Osborne’s) ligament is released under direct vision much like a standard in situ decompression. Using a blunt dissection instrument, a workspace is created proximally and distally to the cubital tunnel. Next an illuminated speculum is introduced, the nerve is directly visualized between 4 and 5 cm proximal and distal to the cubital tunnel, and potential compressive forearm fasciae or fibrous bands are released. Finally, a 15-cm, 30° soft tissue endoscope is introduced into the incision, and viewing the internal anatomy on a video monitor, the decompression continues using longer scissors. Any potential bleeding is controlled with a long bayonet bipolar cautery. The authors discuss indications, contraindications, and the surgical technique. Postoperative management and associated complications are also discussed.

Concepts: Surgery, Tissues, Surgeon, Ulnar nerve, Ulnar artery, Cubital tunnel, Ulnar nerve entrapment, Cauterization

27

PURPOSE: Acute elbow instability leading to dislocation is thought to be a spectrum initiated by an injury to the lateral stabilizing structures of the elbow. Previous cadaveric studies have shown elbow dislocations to occur in flexion. The purpose of this study was to analyze videographic evidence of the deforming forces and upper extremity position during elbow dislocations. We sought to corroborate previous biomechanics studies with in vivo observations. METHODS: We included 62 YouTube.com videos with a clear videographic view of an elbow dislocation. Three senior elbow surgeons independently evaluated arm position at the time of dislocation, along with the suspected deforming forces at the elbow based on these positions. RESULTS: Of the 62 visualized elbow dislocation events, the vast majority (92%) dislocated at or near full extension. The most common arm positions were forearm pronation (68%) with shoulder abduction (97%) and forward flexion (63%). The typical elbow deforming forces were a valgus moment (89%), an axial load (90%), and progressive supination (94%). We identified 4 discrete patterns of arm position and deforming forces. CONCLUSIONS: Acute elbow dislocations in vivo occur in relative extension irrespective of forearm position, a finding distinct from previous cadaveric studies. The most common mechanism appears to involve a valgus moment to an extended elbow, which suggests a requisite disruption of the medial collateral ligament, the known primary constraint to valgus force. These videographic findings suggest that some acute elbow dislocations may result from acute valgus instability and therefore are distinct in nature and mechanism from posterolateral rotatory instability. This information could lead to improved understanding of the sequence of structural failure, modification of rehabilitation protocols, and overall treatment. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic IV.

Concepts: Knee, Shoulder, Forearm, Upper limb, Joint dislocation, Work hardening, Dislocation, Pronation

27

Solutions containing bacillus Calmette-Guérin (BCG), a live attenuated form of Mycobacterium bovis or Mycobacterium tuberculosis, commonly are injected intravesically to treat tumors of the urinary bladder. We report a case of acute mycobacterial flexor tenosynovitis in a health care worker who inadvertently inoculated her finger via needlestick while preparing BCG solution for intravesicular administration. She was treated successfully with immediate operative intervention followed by 6 months of antimycobacterial antibiotics. Of 3 previous reports of hand infections following self-inoculation with BCG solutions, this case is unique owing to rapid onset of acute mycobacterial flexor tenosynovitis and positive intraoperative mycobacterial cultures. Needlesticks with BCG-containing solutions, especially into the flexor tendon sheath, should be treated with timely surgical debridement and appropriate antimycobacterial management.

Concepts: Health care, Urinary bladder, Tuberculosis, Mycobacterium, Mycobacterium tuberculosis, Mycobacterium bovis, Bacillus Calmette-Guérin, Common flexor tendon