Triceps-sparing extra-articular step-cut olecranon osteotomy for distal humeral fractures: an anatomic study

Lateral epicondyle osteotomy approach vs. olecranon osteotomy approach: an anatomic study of cadavers

BACKGROUND

Exposure of the articular surface is the key to successful open reduction and internal fixation treatment for coronal shear fractures of the distal humerus. The olecranon osteotomy approach has previously been described as one of the most effective exposure approaches. Nevertheless, this approach cannot expose the anterior trochlea, and it is impossible to reduce and fix the capitellum under direct vision. The purpose of this study was to compare the exposure of the articular surface of the distal humerus between the lateral epicondyle osteotomy approach (group L) and the olecranon osteotomy approach (group O).

METHODS

Each approach was performed on 8 freshly frozen upper limbs of adult cadavers. After each approach was completed, a 0.5-mm Kirschner wire is inserted along the edge to mark the visible part of the articular surface. Then, the soft tissue of each elbow is removed, and a surface-scanning system is used to create a digital 3-dimensional model. The visible part of the articular surface obtained by each surgical approach was mapped and quantified using markers created by Kirschner wires.

RESULTS

The lateral epicondyle osteotomy approach and the olecranon osteotomy approach exposed 0.8 ± 0.0 and 0.6 ± 0.0 of the distal humeral articular surface (P < .001), 1.0 ± 0.0 and 0.3 ± 0.1 of the capitellum (P < .001), 0.6 ± 0.0 and 0.7 ± 0.0 of the trochlea (P < .001), 0.7 ± 0.0 and 0.5 ± 0.1 of the anterior trochlea (P < .001), and 0.5 ± 0.0 and 1.0 ± 0.0 of the posterior trochlea, respectively (P < .001).

CONCLUSION

Compared with the olecranon osteotomy approach, the lateral epicondyle osteotomy approach could more fully expose the total articular surface of the distal humerus, capitellum, and anterior trochlea, but the olecranon osteotomy approach could more fully expose the trochlea and posterior trochlea.

Extra-articular Olecranon Osteotomy for Reconstruction of Distal Humerus Fractures: Technique and Clinical Results

Articular fractures of the distal humerus in adults are challenging fractures requiring adequate surgical exposure for optimum reconstruction. Most commonly, an articular osteotomy of the olecranon is performed, but complications have been reported related to both creating and repairing the articular osteotomy. We describe the use of an extra-articular olecranon osteotomy for approaching articular fractures of the distal humerus. We highlight the surgical steps required to obtain adequate exposure facilitating anatomical reduction, stable fixation, and early range of motion of the elbow joint. This technique can be added to the surgeon's armamentarium for the management of these complex injuries. [Orthopedics. 2022;45(4):e220-e225.].

A biomechanical study comparing the mean load to failure of two different osteosynthesis techniques for step-cut olecranon osteotomy

Background

Olecranon osteotomies are frequently used to expose distal humeral intraarticular fractures. The step-cut olecranon osteotomy (SCOOT) is an augmented version of the oblique olecranon osteotomy, which has recently been evaluated biomechanically with tension band wiring (TBW) fixation. However, complications with TBW are common. In this study, we, therefore, compared the mean load to failure of TBW with compression screws for SCOOT fixation. We hypothesized a higher load to failure for the compression screw group.

Methods

We performed a SCOOT on 36 Sawbones. Eighteen were fixed with TBW, and another 18 with two compression screws. The humeroulnar joint was simulated using an established test setup, which allows the application of triceps traction force through a tendon model to the ulna, while the humeroulnar joint is in a fixed position. Eight models of each fixation group were tested at 20°, and eight at 70° of flexion by isometrical loading until failure, which was defined as either a complete fracture or gap formation of more than 2 mm at the osteotomy site.

Results

At 20° of flexion, mean load to failure was similar between the TBW group (1360 ± 238 N) and the compression screw group (1401 ± 261 N) (P = .88). Also, at 70° of flexion, the mean load to failure was similar between the TBW group (1398 ± 215 N) and the compression screw group (1614 ± 427 N) (P = .28).

Conclusions

SCOOTs fixed with TBW and compression screws showed similar loads to failure. A SCOOT fixed with compression screws might be a valuable alternative for surgeons when treating intraarticular distal humeral fractures. However, future in vivo studies are necessary to confirm our results in a clinical setting.

Predrilled locking compression plate is more accurate than tension band wiring in restoring articular geometry of the ulnar greater sigmoid notch after olecranon Chevron osteotomy

INTRODUCTION

The olecranon Chevron osteotomy (OCO) is commonly used to approach complex intra-articular fractures of the distal humerus. Predrilled tension band wiring (TBW) has historically been used to fix OCO. However, clinical outcomes are burdened by secondary loss of reduction and up to 21.3% non-union rates. The biomechanical stability of anatomic locking compression plate (LCP) was reported to be superior to TBW in olecranon fracture fixation. We hypothesised that this implant may also be superior to TBW in the anatomic reconstruction of the articular surfaces of the ulnar greater sigmoid notch after OCO by predrilling the holes of the angular stable plate with the threaded drill guide prior to osteotomy.

MATERIALS AND METHODS

Lateral standardised and calibrated radiographs of twenty synthetic ulnar bones were obtained using a custom-made holder prior to preparation by a senior orthopaedic trauma surgeon. Ten specimens were then predrilled using the threaded drill bit guide of an olecranon LCP, while the other ten samples were predrilled with two 1.6 mm Kirschner wires. A distal "V" OCO was performed using a 0.6 mm oscillating saw. After repositioning and fixation with the corresponding device, lateral radiographs were repeated. Two independent observers used the TraumaCad planning software to document the articular geometry of the ulnar greater sigmoid notch pre- and postoperatively. The diameter of the best-fitting circle (diameter), the distance between the tip of the coronoid and the olecranon processes (distance) and the maximum articular depth were measured.

RESULTS

With the TBW technique, after OCO and fixation, all three postoperative measurements were significantly (p≤0.001) different from preoperative measurements. The diameter and distance increased by a mean of 1.5±0.5 mm and 0.9±0.3 mm, respectively, while the depth decreased by a mean of 0.2±0.1 mm. In contrast, no significant differences between pre- and postoperative measurements were observed with the LCP technique (p≥0.13). Inter and intra-observer measurement reliability was strong to very strong (intraclass correlation coefficients≥0.793) for all three variables.

CONCLUSION

Our study reveals that the predrilled LCP technique is more accurate than the predrilled TBW in restoring the anatomic articular geometry of the ulnar greater sigmoid notch after OCO.

Effect of trochleocapitellar index on adult patient-reported outcomes after noncomminuted intra-articular distal humeral fractures

BACKGROUND

Anatomic surgical reduction of intra-articular fractures of the distal humerus is important to achieve the best long-term outcomes and prevent post-traumatic arthritis. In this study we compared the radiographic reduction using the trochleocapitellar index. We also correlated the trochleocapitellar index to the functional outcomes next to the comparison of the triceps brachii lifting approach and olecranon osteotomy approach, 2 common approaches for distal humeral fractures.

METHODS

From January 2006 to June 2016, patients with elbow fractures were registered in 4 centers. The trochleocapitellar index, a ratio between the angle of the capitellum and the trochlea to the midline of the distal humerus on anterior-posterior radiographs, was calculated for included patients. Functional outcomes were measured using the Oxford Elbow Score and the Mayo Elbow Performance Score. Bone healing was measured using radiographic union scoring.

RESULTS

There were 86 patients enrolled: 46 in the olecranon osteotomy group and 40 in the triceps lifting group. Functional outcomes and bone healing did not differ between the approaches. Functional results had a medium correlation with the trochleocapitellar index, which did not differ between the 2 approaches (olecranon osteotomy group, κ = 0.56; triceps lifting group, κ = 0.57; P = .7932).

CONCLUSIONS

The trochleocapitellar index has a moderate predictive value on the functional results after 12 months after open reduction and internal fixation of intra-articular distal humeral factures. There is no difference in reduction, as measured by trochlear index and functional outcome scores, between the olecranon osteotomy approach and the triceps brachii lifting approach groups.