Role of Lateral Extra-articular Tenodesis in Restraining Internal Tibial Rotation: In Vitro Biomechanical Assessment of Lateral Tissue Engagement.

BACKGROUND: The way in which force increases in the anterolateral tissues and the lateral extra-articular tenodesis (LET) tissue to resist internal rotation (IR) of the tibia after anterior cruciate ligament (ACL) reconstruction in isolation and after LET augmentation, respectively, is not well understood. PURPOSE: (1) To compare in a cadaveric model how force increases (ie, engages) in the anterolateral tissues with IR of the tibia after isolated ACL reconstruction and in the LET tissue after augmentation of the ACL reconstruction with LET and (2) to determine whether IR of the tibia is related to engagement of the LET tissue. STUDY DESIGN: Controlled laboratory study. METHODS: IR moments were applied to 9 human cadaveric knees at 0°, 30°, 60°, and 90° of flexion using a robotic manipulator. Each knee was tested in 2 states: (1) after isolated ACL reconstruction with intact anterolateral tissues and (2) after LET was performed using a modified Lemaire technique with the LET tissue fixed at 60° of flexion under 44 N of tension. Resultant forces carried by the anterolateral tissues and the LET tissue were determined via superposition. The way force increased in these tissues was characterized via parameters of tissue engagement, namely in situ slack, in situ stiffness, and tissue force at peak applied IR moment, and then compared (α < .05). IR was related to parameters of engagement of the LET tissue via simple linear regression (α < .05). RESULTS: The LET tissue exhibited less in situ slack than the anterolateral tissues at 30°, 60°, and 90° of flexion (P≤ .04) and greater in situ stiffness at 30° and 90° of flexion (P≤ .043). The LET tissue carried greater force at the peak applied IR moment at 0° and 30° of flexion (P≤ .01). IR was related to the in situ slack of the LET tissue (R2≥ 0.88; P≤ .0003). CONCLUSION: LET increased restraint to IR of the tibia compared with the anterolateral tissue, particularly at 30°, 60°, and 90° of flexion. IR of the tibia was positively associated with in situ slack of the LET tissue. CLINICAL RELEVANCE: Fixing the LET at 60° of flexion still provided IR restraint in the more functionally relevant flexion angle of 30°. Surgeons should pay close attention to the angle of internal and/or external tibial rotation when fixing the LET tissue intraoperatively because this surgical parameter is related to in situ slack of the LET tissue and, therefore, the amount of IR of the tibia.

Complications of Wrist and Hand Arthroscopy.

Arthroscopy of the wrist continues to evolve and advance as a valuable clinical technique in hand surgery. This article aims to address safety of wrist arthroscopy and provide an overview of the known iatrogenic complications. Ultimately, the likelihood of associated injuries during wrist arthroscopy is dependent on the surgeon's ability and understanding of the equipment. Case volume and duration of experience directly correlate with mitigating iatrogenic injury and optimizing patient outcomes.

Characterizing the Propionibacterium Load in Revision Shoulder Arthroplasty: A Study of 137 Culture-Positive Cases.

BACKGROUND: Propionibacterium is commonly recovered from explants or surrounding tissues in revision shoulder arthroplasty. Rather than attempting to differentiate a true infection from a false-positive result on the basis of the number of positive cultures, we characterized the amount of these bacteria in each specimen and shoulder. METHODS: The study included 137 revision shoulder arthroplasties from which a minimum of 4 specimens had been submitted for culture and at least 1 was positive for Propionibacterium. Standard microbiology procedures were used to assign a semiquantitative value (0.1, 1, 2, 3, or 4), called the Specimen Propi Value, to the amount of growth in each specimen. The sum of the Specimen Propi Values for each shoulder was defined as the Shoulder Propi Score, which was then divided by the total number of specimens to calculate the Average Shoulder Propi Score. RESULTS: The number and percentage of positive specimen-specific cultures (of material obtained from the stem explant, head explant, glenoid explant, humeral membrane, collar membrane, other soft tissue, fluid, or other) per shoulder ranged from 1 to 6 and 14% to 100%. A high percentage of specimens (mean, 43%; median, 50%) from the culture-positive shoulders showed no growth. Only 32.6% of the fluid cultures were positive in comparison with 66.5% of the soft-tissue cultures and 55.6% of the cultures of explant specimens. The average Specimen Propi Value (and standard deviation) for fluid specimens (0.35 ± 0.89) was significantly lower than those for the soft-tissue (0.92 ± 1.50) and explant (0.66 ± 0.90) specimens (p < 0.001). The Shoulder Propi Score was significantly higher in men (3.56 ± 3.74) than in women (1.22 ± 3.11) (p < 0.001). Similarly, men had a significantly higher Average Shoulder Propi Score (0.53 ± 0.51) than women (0.19 ± 0.43) (p < 0.001). CONCLUSIONS: This investigation suggests that Propionibacterium is unevenly distributed within culture-positive revised shoulders. As a result, the specimen number and source (explant, soft tissue, or fluid) have major influences on the culture results for a revised shoulder arthroplasty. We found no evidence that suggested useful threshold values for defining a true infection. LEVEL OF EVIDENCE: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Ulnar-Sided Wrist Pain due to Long Ulnar Styloid: A Case Report.

Ulnar styloid impaction syndrome involves repetitive friction between an excessively long ulnar styloid and the carpus, resulting in chondromalacia, synovitis, and pain. The arthroscopic diagnosis, evaluation, and management of this syndrome are not well characterized. We present a patient with chronic wrist pain of unknown origin, culminating with arthroscopic findings demonstrating substantial loss of articular cartilage on both the lunate and triquetrum. The patient successfully underwent operative ulnar styloid excision, ultimately resolving chronic wrist pain symptomology.

Arthroscopic dorsal wrist ganglion excision with color-aided visualization of the stalk: minimum 1-year follow-up.

BACKGROUND: Dorsal wrist ganglia (DWG) are a common, benign soft-tissue mass of the wrist. Excision of DWG is a common procedure performed by hand surgeons and may be performed using either open or arthroscopic techniques. This study aims to evaluate the frequency of stalk visualization with intralesional injection of inert dye in the course of arthroscopic excision along with incidence of recurrence with a minimum of 1-year follow-up. METHODS: Upon IRB approval, a retrospective chart review was performed identifying 27 patients who had consecutively undergone arthroscopic excision of a DWG with the color-aided technique at our institution with a minimum follow-up duration of 12 months. Intraoperative findings were reviewed. Patients were contacted to investigate for incidence of recurrence. RESULTS: Of the 27-patient cohort, the ganglion stalk was identified in 100 % of the color-aided arthroscopic DWG excisions. Ganglion recurrence was identified in one patient, an incidence of 3.7 %. CONCLUSIONS: The color-aided technique for arthroscopic DWG visualization was found to be a safe and valuable tool for surgeons performing arthroscopic DWG resection. The intraarticular ganglion stalk was identified in 100 % of cases and patients responded well with a low incidence of recurrence.

Incidence of failure of continuous peripheral nerve catheters for postoperative analgesia in upper extremity surgery.

PURPOSE: To explore the incidence of failure of continuous peripheral nerve blockade (CPNB) after upper extremity operations. METHODS: Patient data regarding postoperative CPNB were retrospectively obtained from our institution's regional anesthesia database. Documented information on the first postoperative day included pain assessment ratings (numerical verbal pain scale, patient-reported breakthrough pain upon perceived return of sensation, appearance of the catheter site, complications, time of return of sensation, day of return of sensation, residual blockade, patient satisfaction with the block, and whether patient would receive the block again). RESULTS: A total of 207 patients received CPNB for postoperative analgesia. The failure rate on the first postoperative day for infraclavicular (133 patients) and supraclavicular (58 patients) CPNB was 19% and 26%, respectively. Interscalene CPNB (16 patients) yielded 3 incidences of failure. No significant difference was found between supraclavicular and infraclavicular block techniques. In addition, no significant differences were found between the incidences of CPNB failures with potentially more painful surgeries involving bone compared with potentially less painful soft tissue procedures. CONCLUSIONS: The CPNB technique used for hand surgery postoperative analgesia was associated with nontrivial failure rates. The potential of CPNB failure and resulting breakthrough pain upon recovery from the primary nerve block is important to help establish patient expectations. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Outcomes of ulnar shortening osteotomy fixed with a dynamic compression system.

PURPOSE: To evaluate the outcomes of patients with ulnar impaction syndrome treated with a jig-facilitated, oblique, diaphyseal ulnar shortening osteotomy and fixed with a TriMed (Santa Clarita, CA) ulnar osteotomy compression plate. METHODS: A retrospective chart review of patients with ulnar impaction syndrome identified 38 patients who had had ulnar shortening osteotomy and fixation with the TriMed dynamic compression system. The following clinical data were obtained: patient age, sex, follow-up range of motion, grip strength, and complications. After a minimum of 2 years after surgery, patients reported complications and completed a Disabilities of the Arm, Shoulder, and Hand questionnaire. RESULTS: Eight patients were lost to follow-up. Compared to the opposite limb at an average of 8 months after surgery, the remaining 30 patients attained 92% to 97% of wrist and forearm motion and 71% of grip strength. The average Disabilities of the Arm, Shoulder, and Hand score was 12 after a minimum of 2 years after surgery. Four patients required plate removal due to irritation. Two patients reported persistent ulnar-sided pain, and 2 other patients developed atrophic nonunions and required autologous bone grafting. There were no infections. CONCLUSIONS: Ulnar shortening osteotomy using the TriMed system yielded good clinical outcomes that are comparable to those previously documented using other systems. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Complications of wrist arthroscopy.

PURPOSE: The purpose of this systematic review was to address the incidence of complications associated with wrist arthroscopy. Given the paucity of information published on this topic, an all-inclusive review of published wrist arthroscopy complications was sought. METHODS: Two independent reviewers performed a literature search using PubMed, Google Scholar, EBSCO, and Academic Megasearch using the terms "wrist arthroscopy complications," "complications of wrist arthroscopy," "wrist arthroscopy injury," and "wrist arthroscopy." Inclusion criteria were (1) Levels I to V evidence, (2) "complication" defined as an adverse outcome directly related to the operative procedure, and (3) explicit description of operative complications in the study. RESULTS: Eleven multiple-patient studies addressing complications of wrist arthroscopy from 1994 to 2010 were identified, with 42 complications reported from 895 wrist arthroscopy procedures, a 4.7% complication rate. Four case reports were also found, identifying injury to the dorsal sensory branch of the ulnar nerve, injury to the posterior interosseous nerve, and extensor tendon sheath fistula formation. CONCLUSIONS: This systematic review suggests that the previously documented rate of wrist arthroscopy complications may be underestimating the true incidence. The report of various complications provides insight to surgeons for improving future surgical techniques. LEVEL OF EVIDENCE: Level IV, systematic review of Levels I-V studies.

The importance of pronator quadratus repair in the treatment of distal radius fractures with volar plating.

BACKGROUND: Open reduction internal fixation (ORIF) of distal radius fractures via a volar approach involves surgical release of the overlying pronator quadratus (PQ) muscle. Complete repair of the PQ, defined as full and stable replacement of the periphery of the PQ back to its original anatomic location, is not always possible upon conclusion of the operation. Postoperative consequences of incomplete PQ repair with regards to range of motion (ROM), grip strength, and complications are not well documented. It was hypothesized that the completeness of PQ repair would yield no significant difference in the postoperative ROM, grip strength, and incidence of complications. METHODS: A retrospective review was performed of 110 repairs of distal radius fractures with ORIF via placement of a volar locking plate. The following clinical data were extracted: complete or incomplete PQ repair, patient age, gender, follow-up ROM/grip strength, and incidence of postoperative complications. RESULTS AND CONCLUSIONS: No significant difference in ROM, grip strength, and postoperative complications was detected between the complete and incomplete PQ repair groups. Complications consisted of two incidences of malunion requiring revision surgery and one occurrence of complex regional pain syndrome. There were no tendon ruptures. No statistical difference in ROM/grip strength or incidence of postoperative complications was detected between the complete and incomplete PQ repair groups. Regardless of the level of injury sustained by the PQ, surgeons should make an effort to cover the distal aspect of the volar plate during closure following distal radius fracture ORIF. Coverage of the distal aspect of the plate with the PQ (at a minimum) provides adequate results in ROM and grip strength, as well as protection against flexor tendon injury. LEVEL OF EVIDENCE: Therapeutic Level III: Retrospective Comparative Study.

Localized heating on silicon field effect transistors: device fabrication and temperature measurements in fluid.

We demonstrate electrically addressable localized heating in fluid at the dielectric surface of silicon-on-insulator field-effect transistors via radio-frequency Joule heating of mobile ions in the Debye layer. Measurement of fluid temperatures in close vicinity to surfaces poses a challenge due to the localized nature of the temperature profile. To address this, we developed a localized thermometry technique based on the fluorescence decay rate of covalently attached fluorophores to extract the temperature within 2 nm of any oxide surface. We demonstrate precise spatial control of voltage dependent temperature profiles on the transistor surfaces. Our results introduce a new dimension to present sensing systems by enabling dual purpose silicon transistor-heaters that serve both as field effect sensors as well as temperature controllers that could perform localized bio-chemical reactions in Lab on Chip applications.