Rigorous Mathematical Derivation of Inclination Angle for Single Cut Rotational Osteotomy for Tibia Deformity Correction.

Background: To rigorously derive easy to use formulae for the inclination angle for single cut rotation osteotomy that can be used for tibia deformity correction. Method: Three theorems were proven using trigonometric identities and concepts of linear algebra. These were rigorously shown. The three concepts were how to convert deformities in an AP/Lateral plane to an oblique plane deformity with a true angular magnitude of deformity; how to project an angular quantity from one plane to another; and the calculation of the inclination angle for the oblique osteotomy plane. All figures in this article were created by the authors of this paper. Results: From the formula derived, a statistical t-test was performed that showed no significant difference between the formula derived in this paper and the original Sangeorzan paper charts (p=0.8782). Conclusions: The formulae described in this article are a method to accurately calculate the inclination angle of the osteotomy for a single cut rotational osteotomy for tibial deformity correction. Clinical Relevance: The article gives a deeper understanding of fundamental concepts behind deformity correction and provides an easy-to-use mathematical formula to calculate the osteotomy inclination for single cut rotational osteotomies.

Anatomy of the Intermetatarsal Facets of the Fourth and Fifth Metatarsals.

BACKGROUND: The intermetatarsal joint between the fourth and fifth metatarsals (4-5 IM) is important in defining fifth metatarsal fractures. The purpose of the current study was to quantify this joint in order to determine the mean cartilage area, the percentage of the articulation that is cartilage, and to give the clinician data to help understand the joint anatomy as it relates to fifth metatarsal fracture classification. METHODS: Twenty cadaver 4-5 IM joints were dissected. Digital images were taken and the articular cartilage was quantified by calibrated digital imaging software. RESULTS: For the lateral fourth proximal intermetatarsal articulation, the mean area of articulation was 188 ± 49 mm2, with 49% of the area composed of articular cartilage. The shape of the articular cartilage had 3 variations: triangular, oval, and square. A triangular variant was the most common (80%, 16 of 20 specimens). For the medial fifth proximal intermetatarsal articulation, the mean area of articulation was 143 ± 30 mm2, with 48% of the joint surface being composed of articular cartilage. The shape of the articular surface was oval or triangular. An oval variant was the most common (75%, 15 of 20 specimens). CONCLUSION: This study supports the notion that the 4-5 IM joint is not completely articular and has both fibrous and cartilaginous components. CLINICAL RELEVANCE: The clinical significance of this study is that it quantifies the articular surface area and shape. This information may be useful in understanding fifth metatarsal fracture extension into the articular surface and to inform implant design and also help guide surgeons intraoperatively in order to minimize articular damage.

Short-term Medical Complications Following Short Versus Long Cephalomedullary Nails.

The purpose of this retrospective cohort study was to evaluate whether there is an increased rate of short-term medical complications following short vs long cephalomedullary nails for the treatment of intertrochanteric hip fractures. A total of 899 patients treated surgically with cephalomedullary nails from January 1, 2005, to September 1, 2014, were included. Patients who received short nails (n=334) were older and had a higher incidence of coronary artery disease and diabetes mellitus compared with patients who received long nails (n=565). The incidences of 30-day medical complications, including myocardial infarction, stroke, deep venous thrombosis, pulmonary embolism, blood transfusion, non-surgical site infection, surgical site infection, and mortality, were recorded. The orthopedic complications of periprosthetic fracture of the ipsilateral hip and implant failure through the latest outpatient follow-up were recorded. No significant difference was found between nails for any studied medical complication (63.5% short vs 66.0% long, P=.4393) or mortality (6.9% short vs 5.3% long, P=.3322). There was also no significant difference in the incidence of orthopedic complications (P=.70). Longer operating room time was associated with superficial surgical site infection. [Orthopedics. 2018; 41(5):e636-e642.].

Intraoperative chlorhexidine irrigation to prevent infection in total hip and knee arthroplasty.

BACKGROUND: Surgical site irrigation during total hip (THA) and total knee (TKA) arthroplasty is a routine practice among orthopaedic surgeons to prevent periprosthetic joint infection. The purpose of this study was to evaluate the effect of chlorhexidine gluconate (CHG) irrigation on infection rates following THA and TKA. METHODS: Arthroplasties performed before September 2014 served as controls. THA performed before September 2014 (N = 253) underwent intraoperative irrigation with 0.9% saline followed by a 2-minute soak with <2% dilute povidone-iodine. TKA (N = 411) patients underwent only intraoperative saline irrigation. After October 2014, all patients (248 TKA and 138 THA) received intraoperative irrigation with 0.9% saline and periodic 0.05% CHG solution followed by a final 1-minute soak in CHG with immediate closure afterward. RESULTS: In this 2:1 comparison of consecutive patients, there were no differences in patient demographics between the 2 groups. No difference was noted in wound healing concerns subjectively, and no statistically significant association in nonsurgical site infections, superficial surgical site infection, and deep surgical site infection rates between the 2 groups (nonsurgical site infections [THA: P = .244, TKA: P = .125]; superficial surgical site infection [THA: P = .555, TKA: P = .913]; and deep surgical site infection [THA: P = .302, TKA: P = .534]). CONCLUSIONS: We were unable to discern a difference in infection rates between chlorhexidine irrigation and our prior protocols using dilute Betadine for THA and 0.9% saline for TKA. The theoretic advantages of dilute CHG retention during closure appear to be safe without infectious concerns.