Hypothermia in Total Joint Arthroplasty: A Wake-Up Call.

BACKGROUND: Total joint patients are particularly vulnerable to perioperative hypothermia (PH) (combined effects of anesthesia, radiation, and convective heat loss from exposed skin surfaces and cool temperatures in the operating room). There are limited studies on PH in these patients. METHODS: In a retrospective review of 204 patients undergoing primary hip and 179 undergoing primary knee replacement surgeries, time and temperature parameters were collected from the electronic health records from preoperative and postoperative recovery room nursing assessments, intraoperative anesthesia records, and floor nursing notes. Basic patient demographic data was recorded. Chi-squared and paired t-tests were used to compare between hypothermic and normothermic groups. RESULTS: At the time of incision, 60 of 179 (34%) total knee arthroplasty (TKA) patients and 80 of 204 (39%) total hip arthroplasty (THA) patients were hypothermic. In THA patients, 65% remained hypothermic for the duration of anesthesia compared to 33% of TKA patients. The largest drop in core body temperature in both THA and TKA patients occurred between preoperative holding and induction of anesthesia. In THA patients, spinal anesthesia had a significantly higher occurrence of PH. No significant patient factor was found to increase risk. CONCLUSION: Emphasis on preoperative holding protocols, decreasing time from operating room entry to incision, and increasing ambient room temperature could reduce risk of hypothermia in total joint replacement patients.

Corrosion and adverse local tissue reaction after total hip arthroplasty with a modular titanium alloy femoral neck.

This report describes a case of mechanically assisted crevice corrosion and secondary adverse local tissue reaction in a patient following a total hip arthroplasty, utilizing a modular neck (bi-modular) femoral component. Radiographic evaluation demonstrated a well-positioned, stable, cementless arthroplasty. Upon further evaluation, the patient had elevated serum cobalt and chromium levels, and magnetic resonance imaging demonstrated a periprosthetic pseudotumor. Corrosion of both the neck-stem and head-neck junctions was suspected. At the time of surgery, the neck-body junction was pristine; however, the head-neck junction of the implant demonstrated severe corrosive wear, a problem that has been reported only once previously with this particular bi-modular implant. This serves as a reminder that any modular junction may be susceptible to corrosion and not all bi-modular designs behave similarly.

Single incision power optimizing cost-effective (SPOC) distal biceps repair.

BACKGROUND: The purpose of this study was to review the results of a single anterior incision distal biceps tendon repair that reattaches the tendon to its posterior anatomic insertion site. We hypothesize this repair maximizes the supination torque of the biceps muscle throughout the full arc of forearm rotation. METHODS: A consecutive series of patients with distal biceps tears were treated using a technique that reattaches the distal biceps tendon to the posterior radial surface similar to a 2-incision repair, which optimizes the biceps moment arm in all forearm positions including maximum supination. This method of distal biceps reattachment has been utilized in our practice since December 2008 on 40 distal biceps tendon repairs. Biodex testing was used to quantify the peak supination torque, the supination work, and the power of supination at each degree of forearm rotation and included on patients with a minimum clinical follow up of 12 months. Range of motion was also recorded. RESULTS: Thirty patients met the inclusion criteria. Three patients, 2 of whom were lost to follow-up and 1 with bilateral repairs, were not included in this study. Seventeen of the remaining 27 patients completed strength testing using a Biodex Isokinetic Testing machine. Supination strength averaged 91% and 91% of the uninjured side at 60 and 120 deg/sec, respectively. Twenty-five (93%) patients reported no pain and had returned to work or normal activities. CONCLUSION: A single anterior incision distal biceps tendon repair that maximizes supination torque throughout full forearm rotation has been utilized. No specialized anchors or equipment are required. LEVEL OF EVIDENCE: Level IV, Case Series, Treatment Study.

Prevalence of stump overgrowth in pediatric burn patient amputations.

BACKGROUND: Pediatric patients sometimes require amputation as part of their life-saving burn care. Bone overgrowth is known to occur in these amputation patients at rates of 4% to 43% depending on the study. METHODS: We conducted a retrospective study of all patients who underwent amputation at a children's burn center for a 45-year span. There were 18,880 burn patients during this time frame and 149 pediatric patients with amputation who survived long-term were studied. Burn types included flame, electrical, scald, thermal, and combination types in order of prevalence. We studied bone overgrowth as defined as those children requiring revision surgery. RESULTS: One hundred forty-nine patients underwent a total of 259 amputations. The average age at the time of amputation was 7.48 years. Stump overgrowth occurred in 15 patients (10.1%) or 15 of the 259 amputations (5.8%) overall. Bone overgrowth occurred in 11 of 104 flame burn patients (10.6%), 3 of 32 electrical burns (9.4%), and 1 of 9 scald burns (11.1%). Many patients had multiple amputations so the incidence for amputations was 6.1% (11 of 179) for flame, 5.4% (3 of 56) for electrical, and 5.9% (1 of 17) for scald burns. The mean time to overgrowth from primary amputation to revision surgery was 41.5 months. Overgrowth was more common in the lower extremities (17 of 104, or 16.3%) than in the upper extremities (3 of 153, or 2%). CONCLUSIONS: Bony overgrowth after amputation in pediatric burn patients occurs at a rate of 10.1% of patients or 5.8% of amputations. Younger children are more likely to have overgrowth. The type of burn does not influence overgrowth and lower extremity amputations are more likely to show overgrowth than upper extremities. LEVEL OF EVIDENCE: Level IV, case series.

Biofunctionalization on alkylated silicon substrate surfaces via "click" chemistry.

Biofunctionalization of silicon substrates is important to the development of silicon-based biosensors and devices. Compared to conventional organosiloxane films on silicon oxide intermediate layers, organic monolayers directly bound to the nonoxidized silicon substrates via Si-C bonds enhance the sensitivity of detection and the stability against hydrolytic cleavage. Such monolayers presenting a high density of terminal alkynyl groups for bioconjugation via copper-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC, a "click" reaction) were reported. However, yields of the CuAAC reactions on these monolayer platforms were low. Also, the nonspecific adsorption of proteins on the resultant surfaces remained a major obstacle for many potential biological applications. Herein, we report a new type of "clickable" monolayers grown by selective, photoactivated surface hydrosilylation of α,ω-alkenynes, where the alkynyl terminal is protected with a trimethylgermanyl (TMG) group, on hydrogen-terminated silicon substrates. The TMG groups on the film are readily removed in aqueous solutions in the presence of Cu(I). Significantly, the degermanylation and the subsequent CuAAC reaction with various azides could be combined into a single step in good yields. Thus, oligo(ethylene glycol) (OEG) with an azido tag was attached to the TMG-alkyne surfaces, leading to OEG-terminated surfaces that reduced the nonspecific adsorption of protein (fibrinogen) by >98%. The CuAAC reaction could be performed in microarray format to generate arrays of mannose and biotin with varied densities on the protein-resistant OEG background. We also demonstrated that the monolayer platform could be functionalized with mannose for highly specific capturing of living targets (Escherichia coli expressing fimbriae) onto the silicon substrates.