Analysis and comparison of the biomechanical properties of univalved and bivalved cast models.

PURPOSE: Fiberglass casts are frequently valved to relieve the pressure associated with upper extremity swelling after a surgical procedure or when applied after reduction of a displaced fracture in a child. Although different opinions exist regarding the valving of casts, no research to date has explored the biomechanical effects of this commonly used technique. As cast integrity is essential for the maintenance of fracture reduction, it is important to understand whether casts are structurally compromised after valving. Understanding the effects of valving on cast integrity may help guide clinicians in the technique of valving while minimizing the potential for a loss of fracture reduction. METHODS: Thirty standardized cylindrical fiberglass cast models were created. Ten models were left intact, 10 were univalved, and 10 were bivalved. All the models were mechanically tested by a 3-point bending apparatus secured to a biaxial materials testing system. Load to failure and bending stiffness were recorded for each sample. Differences in load of failure and bending stiffness were compared among the groups. RESULTS: Unvalved cast models had the highest failure load and bending stiffness, whereas bivalved casts showed the lowest value for both failure load and bending stiffness. Univalved casts had a failure load measured to be between those of unvalved and bivalved cast models. Analysis of variance showed significance when failure load and bending stiffness data among all the groups were compared. A post hoc Bonferroni statistical analysis showed significance in bending stiffness between intact and bivalved models (P < 0.01), intact and univalved models (P < 0.01), but no significant difference in bending stiffness between univalved and bivalved models (P > 0.01). Differences in measured failure load values were found to be statistically significant among all cast models (P < 0.01). CONCLUSIONS: Valving significantly decreases the bending stiffness and load to failure of fiberglass casts. Univalved casts have a higher load to failure than bivalved casts. CLINICAL RELEVANCE: Valving adversely alters the structural integrity of fiberglass casts. This may impair a cast's ability to effectively immobilize an extremity or maintain a fracture reduction.

Why Make the Cut? Trochanteric Slide Osteotomy Can Improve Exposure to the Anterosuperior Acetabulum.

OBJECTIVE: To define relative increases in visual bony surface area and access to critical landmarks with the addition of a trochanteric slide osteotomy to a Kocher-Langenbeck approach. METHODS: A Kocher-Langenbeck approach followed by a trochanteric slide osteotomy was sequentially performed on 10, fresh-frozen, hemipelvectomy cadaveric specimens. Visual and palpable access to relevant surgical landmarks was recorded. Calibrated digital photographs were taken of each approach and analyzed using Image J. RESULTS: The acetabular surface area exposed was 27.66 (±6.67) cm2 for a Kocher-Langenbeck approach. This increased to and 41.82 (±7.97) cm2 with the addition of a trochanteric osteotomy. The exposed surface area was increased by 51.2% for the trochanteric osteotomy (P < 0.001). The superior margin of the acetabulum could be visualized and palpably accessed in both exposures. Access to the more anterosuperior portions of the acetabulum was consistently possible in the trochanteric osteotomy but not with the Kocher-Langenbeck approach. CONCLUSIONS: A trochanteric osteotomy may visually improve access to the most anterosuperior acetabulum but does not significantly improve surgical access to relevant portions of the superior acetabulum when compared with a Kocher-Langenbeck approach.

A Novel Surgical Technique for Glenoid Reconstruction in the Trauma Setting With a Distal Tibia Allograft: A Case Report.

CASE: A 21-year-old woman presented with a chronic fracture dislocation of her left shoulder after striking a submerged tree during a watersport activity. She was initially treated at an outside hospital, where she underwent open reduction and internal fixation of her posterior scapula. She presented 8 weeks after index procedure with pain and severely decreased range of motion. Her comminuted and displaced fracture comprising 70% of the anterior superior glenoid was surgically reconstructed using a distal tibia allograft (DTA), resulting in a functional shoulder. CONCLUSION: A DTA is a feasible option to reconstruct the glenoid surface in fracture dislocations of the shoulder with a significant loss of the articular surface.

Surgical Approaches to the Proximal Humerus: A Quantitative Comparison of the Deltopectoral Approach and the Anterolateral Acromial Approach.

BACKGROUND: Debate exists over the optimal approach for addressing fractures of the proximal humerus. The purpose of this study was to objectively quantify the surface area of the humerus exposed using the deltopectoral (DP) and anterolateral acromial (ALA) approaches and to compare visualized and palpable anatomic landmarks. METHODS: Ten arms on five fresh-frozen torsos underwent the DP and ALA approaches. The arms were positioned to simulate a supine patient and held in a fixed position. Visual and/or palpable access to relevant surgical landmarks and the myotendinous junctions were recorded. The myotendinous junctions were used as a rough approximation of consistent proximal exposure of a clinically retracted tuberosity. Landmarks were grouped into quadrants based on the location. Calibrated digital photographs of each approach were analyzed to calculate the surface area and the length of the exposed bone. RESULTS: The DP and ALA approaches exposed 22.9 ± 6.3 cm2 and 16.3 ± 6.4 cm2, respectively (P = 0.03). The DP and ALA approaches provided equivalent visual and palpable access to all landmarks in the superior and inferior quadrants. The ALA allowed improved visual (80% versus 70%) and palpable (100% versus 70%) access to the myotendinous junction of the infraspinatus in the posterior quadrant. The DP approach allowed better access to anterior quadrant structures, including improved ability to visualize the myotendinous junction of the subscapularis (100% versus zero), the subscapularis insertion (100% versus 80%), and the medial anatomic neck (100% versus 20%). Palpable access to the myotendinous junction of the subscapularis (100% versus 70%) and medial anatomic neck (100% versus 60%) was also improved with the DP. CONCLUSIONS: In a cadaver model with fixed arm position, the DP provides increased exposure to the proximal humerus and more reliable access to anterior surgical landmarks, whereas the ALA allows improved access to the most posterior aspect of the shoulder.

A Preoperative Planning Tool: Aggregate Anterior Approach to the Humerus With Quantitative Comparisons.

Extensile approaches to the humerus are often needed when treating complex proximal or distal fractures that have extension into the humeral shaft or in those fractures that occur around implants. The 2 most commonly used approaches for more complex fractures include the modified lateral paratricipital approach and the deltopectoral approach with distal anterior extension. Although the former is well described and quantified, the latter is often associated with variable nomenclature with technical descriptions that can be confusing. Furthermore, a method to expose the entire humerus through an anterior extensile approach has not been described. Here, we illustrate and quantify a technique for connecting anterior humeral approaches in a stepwise fashion to form an aggregate anterior approach (AAA). We also describe a method for further distal extension to expose 100% of the length of the humerus and compare this approach with both the AAA and the lateral paratricipital in terms of access to critical bony landmarks, as well as the length and area of bone exposed.

A Comparison of Exposure Between the Classic and Modified Judet Approaches to the Scapula.

OBJECTIVES: A debate exists over the optimal approach for addressing fractures of the scapula and glenoid. The purpose of this study is to (1) quantify and compare osseous exposure using modified Judet (MJ) and classic Judet (CJ) approaches and (2) assess the change in scapular exposure after triceps release from the inferior glenoid. METHODS: Ten arms on 5 fresh-frozen torsos underwent MJ and CJ approaches. A triceps release was performed following the CJ approach in all specimens. Visual and/or palpable access to relevant surgical landmarks was recorded. Calibrated digital photographs were taken of each approach and analyzed using Image J (NIH, Bethesda, MD) to calculate the surface area of exposed bone. RESULTS: The MJ and CJ approaches exposed 16.8 (±7.58) cm(2) and 98.6 (±25.39) cm(2) of bone, respectively (P < 0.001). The full medial and lateral borders of the scapula were visualized in all approaches with mobilization of the teres minor. Palpable access to the full scapular spine was possible in all cadavers. Although the MJ and CJ approaches only allowed the inferior gleniod neck to be visualized in 1 and 2 specimens, respectively, performing a triceps release provided access to this structure. It also increased the CJ exposure by 12.6 cm(2) (P < 0.001) and allowed palpation of the anterior glenoid margin in 100% of specimens. CONCLUSIONS: In conclusion, the MJ approach allows similar access to landmarks important for reduction and fixation while exposing only 20% of the surface area typically visualized with the CJ approach.