Whether supracondylar osteotomy of the distal humerus should be simultaneously combined with ulnar nerve in situ tension release for the treatment of tardy ulnar nerve palsy associated with cubitus valgus remains controversial. We evaluated a group of patients who underwent this combined operation at the same time, rather than in stages, and evaluated imaging and clinical outcomes for at least 2 years. The results showed that the symptoms and signs of ulnar nerve were improved, the deformity was well corrected, and the function of the elbow joint was not decreased.
In our study, we used supracondylar shortening wedge rotary osteotomy to correct traumatic cubitus valgus. The patients were followed up for at least 2 years. Although the elbow range of motion on the affected side could not be recovered completely, its function was improved compared with that before operation. We used two conventional reconstruction plates or LCP reconstruction plate fixation, which can stabilize the osteotomy so that the elbow joint can get early exercise. We believe that removal of the osteophyte at the tip of the olecranon through posterior capsulotomy is one of the reasons for the increased active elbow extension in our patients. Moreover, the treatment of old nonunion of lateral condyle of the humerus is still controversial[13, 14]. In the study, none of the 11 patients with nonunion of the lateral condyle of the humerus underwent osteosynthesis, this seems to be another reason why our patients with lateral condylar nonunion maintained their elbow ROM postoperatively. Supracondylar osteotomy is usually accompanied by severe complications, including loss of elbow range of motion, lateral condylar fracture necrosis, and persistent nonunion[15, 16]. Therefore, the indication of osteotomy should be considered in patients with elbow pain, limited movement, and tardy ulnar nerve palsy, and other serious complications.
All normal HEW angle was obtained in all patients without recurrence of deformity or residual eminence of the medial condyle. Although there is no consensus, for patients with an angle below 20°, we do not recommend osteotomy as a priority because it is prone to serious complications after osteotomy. If the angle exceeds 20°, supracondylar osteotomy of the distal humerus is usually indicated. Because of the advantages of simplicity and easy implementation, the medial closing-wedge osteotomy is traditionally used to correct cubitus valgus, however, it has been reported that some patients failed to correct deformity, reduced range of motion of the elbow, and other complications postoperative. We found that in patients with cubitus valgus, the length of the humerus on the affected side is longer than that on the healthy side. Studies have shown that the length of the humerus after supracondylar fracture of the distal humerus increases by 1% of the original length on average even with effective internal fixation. Therefore, we believe that the abnormal increase of humeral length will be more in patients with traumatic cubitus valgus, and long-term cubitus valgus deformity leads to contracture of the extensors of the forearm. The abnormal traction of contracture forearm extensor muscle leads to an abnormal increase of valgus force after the traditional medial closing-wedge osteotomy, which hinders the fixation needed to maintain the correction and easily leads to the failure of fixation and the joint force imbalance. According to this, the osteotomy plane should be shortened by 1ཞ2 cm during the operation. In addition, we should pay attention to the changes in normal structure and biomechanics during the development of traumatic cubitus valgus. Due to the traction of forearm extensor muscles, the distal humerus rotated laterally during healing. Therefore, in the process of osteotomy to correct the deformity, the distal humerus should be rotated medially according to the actual situation to restore the normal structure and biomechanics as much as possible, to increase the range of motion of the elbow joint and reduce the postoperative complications.
Traumatic cubitus valgus deformity can lead to tardy ulnar nerve palsy[20, 21]. Anterior transposition of the ulnar nerve has become the mainstream surgical treatment for tardy ulnar nerve palsy caused by traumatic cubitus valgus deformity. Although this surgical scheme completely decompresses the ulnar nerve and solves the traction and friction of the ulnar nerve during elbow flexion, there are many disadvantages in this surgical method, such as dissociating at least 10 cm ulnar nerve to meet the requirements of anterior transposition, Extensive dissociation increases the injury and does not rule out the possibility of injuring the flexor carpal ulnar muscle and affecting the blood supply of ulnar nerve. Moreover, the fixation time of the elbow joint is long after the operation, the ulnar nerve is mostly located under the soft tissue, the nerve without cubital tunnel protection is easily damaged by an external force, and the incidence of complications such as long-term scar compression is high. Given the prerequisite of traumatic cubitus valgus and the anatomical characteristics of the abnormal prominent medial condyle, the ulnar nerve groove can be expanded appropriately after releasing the ulnar nerve. By expanding the four walls of the cubital canal, the depth and width of the ulnar nerve groove can be expanded, and the instability and dislocation of the ulnar nerve can be solved without changing the normal anatomical structure and course of the ulnar nerve, It avoids the nerve pain and injury caused by an external force. At the same time, it also solves the problem of abnormal reduction of cubital tunnel volume during elbow flexion, which effectively avoids the extreme increase of ulnar nerve internal pressure when elbow flexion, greatly improving ulnar nerve microcirculation and avoiding ulnar nerve injury or aggravation due to ischemia and hypoxia. The combined operation is simple, the trauma is small, the blood supply of the ulnar nerve is not damaged, the release is complete, the curative effect is remarkable, and the recurrence rate of ulnar neuritis is reduced. In the current study, the mean DASH score increased significantly from 29 to 16 at 2 years after surgery (P = 0.001). It seems to be a promising clinical outcome that supracondylar shortening wedge rotary osteotomy combined with in situ tension release of the ulnar nerve can reduce pathological traction of ulnar nerve at the elbow.
The study also has several limitations. The data were collected retrospectively, including only a few patients. In addition, no control group was treated with in situ tension release of the ulnar nerve. All of our patients had a cubitus valgus deformity greater than 20° and underwent correction of the deformity concurrent with ulnar nerve in situ tension release if they wanted. However, few cases require osteotomy and ulnar nerve release in situ at the same time in clinical practice. Patients with elbow flexion contracture tend to rotate the shoulder externally to cover up the flexion contracture. This compensatory movement of the shoulder may overestimate the angle of the HEW. So we need to instruct our patients how to keep their medial and lateral condyles at the same horizontal plane to obtain the correct elbow projection during radiography.
In addition, there is no reliable, reproducible, and effective prognostic indicator for ulnar nerve palsy caused by traumatic cubitus valgus deformity treated by both supracondylar correction osteotomy and ulnar nerve in situ release. The DASH score is a general upper limb function scoring tool. we used it to evaluate the disability of traumatic cubitus valgus deformity. Although retrospective studies usually have selection bias, our study does not have this problem because we performed deformity osteotomy and ulnar nerve in situ tension release simultaneously in all patients. One of our patients was excluded from this study due to a follow-up of fewer than 2 years. The patient's last visit was six months after surgery and the osteotomy site was completely healed at that time. However, the assessment at that time did not seem to be sufficient to judge the outcome of the operation. Therefore, we analyzed the data of 16 patients who were followed up for more than 2 years.
Based on the results of this small retrospective study, we are cautiously optimistic about supracondylar shortening wedge rotary osteotomy combined with in situ tension release of the ulnar nerve for traumatic cubitus valgus with tardy ulnar nerve palsy. This combined operation can significantly improve the function and appearance of the elbow joint and the symptoms of ulnar nerve palsy caused by long-term traction and friction, and effectively prevent ulnar nerve slippage caused by instability of the elbow joint, It is a surgical scheme with anatomical characteristics, simple operation, less trauma, and satisfactory curative effect.