Fracture of proximal radius combined with dislocation of the radial head:a case report

Xiao-Zhen Chen ,Song-Ou Zhang ,Ling-Jie Wang ,Yue-Gang Ma ,Wen-Qing Liang ,Song-Tao Jing ,Jin-Xiang Shang,Xu-Jun Hu1,*

1Shaoxing University School of Medicine,Shaoxing 312000,China.2Department of Orthopedics,Shaoxing People’s Hospital,Shaoxing Hospital Affiliated to Zhejiang University,Shaoxing 312000,China.3School of medicine,Qingdao University,Qingdao 266000,China.4Department of Orthopedics,Zhoushan Hospital of Traditional Chinese Medicine Affiliated to Zhejiang Chinese Medical University,Zhoushan 316000,China.5Department of Orthopedics,The Affiliated Hospital of Shaoxing University,Shaoxing 312000,China.

Abstract Forearm fractures are prevalent which include radius fractures,ulna fractures,or both radius and ulna fractures.Proximal radius fractures combined with dislocations of the radial heads are rare and easily misdiagnosed.The authors present and discuss a case of proximal radius fractures associated with radial head dislocations.A 36 years old male was admitted to the hospital due to pain and activity limitation in his left elbow for 7 hours due to a car accident.An X-ray of the left elbow joint revealed a “l(fā)eft radius fracture with surrounding soft tissue edema”.During the procedure,the radial head was found to be dislocated forward.A 3.0 mm anchor was used to fix the annular ligament.Radius fractures combined dislocations of the radial heads are rare and may be missing the diagnosis.Before undergoing surgery,the possibility of elbow dislocation should be evaluated.Wire anchors can provide reliable fixation.

Keywords: annular ligament;case report;dislocated;forearm fractures radius fracture;radial head

Background

Forearm fractures are prevalent fractures which include radius fractures,ulna fractures,or both radius and ulna fractures [1].This type of fracture is often associated with proximal or distal forearm joint dislocation;the most common types are Galeazzi fracture and Monteggia fracture [2].Radius fractures with radial head dislocations are extremely uncommon.In this report,a case of proximal radius fractures combined dislocations of the radial head has been discussed.In this case,no radial head dislocation was found in the preoperative examination.Intraoperative fluoroscopy showed radial head dislocation after the intraoperative internal fixation device repaired the radial fracture.

Case presentation

All the participants signed informed consent form.The study was approved by the ethics committee of Shaoxing People’s Hospital(2022Z204) and signed informed consent was provided by patients or their families.

A 36 years old male employee was admitted to the hospital due to pain and activity limitation in his left elbow for 7 hours due to a car accident.He was knocked down by a galloping electric motorcycle 7 hours ago while waiting for a traffic light to cross the road.The left forearm and elbow joint first touch the ground.After the injury,he felt pain in the left forearm and elbow,accompanied by deformity and impaired movement of the left forearm.The patient was healthy in the past.The patient had no personal or family history.Physical examination revealed evident swelling of the forearm;purple-red ecchymosis,upper forearm deformity,and a pain visual analogue scale (VAS) score of 5 points.Laboratory findings were normal.An X-ray of the left elbow joint revealed a “l(fā)eft radius fracture,surrounding soft tissue swelling” (Figure 1 A and B).The left forearm was plastered at the emergency room before being admitted to our hospital’s orthopedics department for a “l(fā)eft radius fracture”.During the operation,the C-arm machine fluoroscopy irradiation showed good fracture reduction.The wrist and elbow joints were examined by C-arm fluoroscopy.In the extension position of the wrist and elbow joints,there was no joint dislocation (Figure 2A).When the elbow joint was inspected for inflection,the radial head was observed to be dislocated forward (Figure 2B).Extend the radial incision to the outside of the left elbow,separate the radial head of the left elbow layer by layer,see the left radial head anterior dislocation,the tear of the annular ligament at the ulnar anchor point.The final diagnosis of the presented case was:Fracture of the proximal radius combined with dislocation of the radial head.On the fourth day after admission,the swelling of the forearm was significantly reduced than before,and the left radius fracture was treated with open reduction and internal fixation.After effectively anesthetizing the patient,assume the supine position,sanitize the operation area with povidone-iodine (PVP-I),spread a sterile towel,and apply a sterile tourniquet.Took a 10 cm long radial incision on the left forearm,separated layer by layer into the muscle space,separated and released the deep branch of the left radial nerve,exposed the fractured end of the radius,peeled off the periosteum,removed the blood clot and soft tissue,and piece together large pieces of bone fragments.Place the reconstruction locking plate and fix it with screws.The C-arm machine fluoroscopy irradiation during the procedure demonstrated satisfactory fracture reduction.The wrist and elbow joints were examined by C-arm fluoroscopy.There was no joint dislocation in the extension position of the wrist and elbow joints.When the elbow joint was examined in the flexion position,it was found that the radial head was dislocated forward.Extend the radial incision to the outside of the left elbow,layer by layer,to observe the left radial head anterior dislocation and the annular ligament rupture at the ulnar anchor point.A 3.0 mm anchor was inserted into the ulnar anchor point to fix the annular ligament,and the left radial head was repositioned.The C-arm machine irradiation showed that the radial head had been reset(Figure 2 C and D).After careful hemostasis,the wound was washed with sterile normal saline and PVP iodine.There was no visible active bleeding.A drainage tube was placed in the incision,and the wound was sutured layer by layer.The wound was bandaged with a sterile dressing.The left elbow was flexed at 90 degrees,and the hand supination was outside the plaster.The incision was healed well after operation without any infection or radial nerve injury.After 6 weeks of plaster fixation,instruct the patient to perform functional exercises.Postoperative re-examination of the elbow joint,ulna and radius,and wrist joints X-ray showed that “the middle and upper left radius fractures were changed after internal fixation with steel plate and screws and external plaster fixation change” (Figure 3).Six weeks after surgery,the patient’s elbow joint was moving well and there was no dislocation.

Figure 1 X-ray images of the left elbow joint revealed a “l(fā)eft radius fracture,” surrounding soft tissue swelling. (A) Straight position;(B) Flexion position.

Figure 2 Intraoperative fluoroscopy images.During the operation,the C-arm machine fluoroscopy irradiation showed good fracture reduction. (A) In the extension position of the wrist and elbow joints,there was no joint dislocation;(B) When the elbow joint was inspected for inflection,the radial head was observed to be dislocated forward;(C)After the annular ligament fixed,the left radial head did not show any dislocation in extension;(D) Inflection.

Figure 3 X-ray of elbow joint after operation. (A) the middle and upper left radius fractures were changed after internal fixation with steel plate;(B) screws and external plaster fixation change.

Discussion

The radius and ulna from the forearm,the proximal ulna and the humerus trochlear form a joint,and the distal and radius form the distal radioulnar joint.The radius is associated with the humeral head and ulna at the proximal end,and the ulna and radiocarpal joint at the distal end.The shape of the ulna is straight,and the curved shape of the radius allows it to surround the ulna,which acts as the axis of rotation.The interosseous membrane connects the ulna and radius,the triangular fibrocartilage connects the distal end of the ulna and radius,the collateral ligament complex connects to the proximal radius of the ulna,and the annular ligament surrounds and attaches to the radius head.These structures are in complex forearm fractures.Damage may occur in the medium and cause structural instability[3].

The most common forearm fractures are Monteggia’s fractures and Galeazzi’s fractures.Monteggia’s fracture refers to a fracture of the ulnar shaft combined with dislocation of the radial head (Figure 4A),and Galeazzi’s fracture refers to a fracture of the radius shaft combined with dislocation of the distal joint (Figure 4B).In this case,the patient had a proximal radius fracture coupled with a radial head dislocation (Figure 4C),which is quite rare.In this case,the patient’s elbow was the first to hit the ground.It was speculated that the force acting on the elbow joint caused the annular ligament anchor tear,causing dislocation of the radial head,and then the force was transmitted to the distal end,causing partial tearing of the interosseous membrane.The radius shifts away from the ulna.The body flips during the injury,causing the radius to collide with the humerus,resulting in a proximal radius fracture (Figure 5).This case needs to be distinguished from Essex-Lopresti injury.Essex-Lopresti injury is characterized by the lower ulnar-radial joint dislocation,interosseous membrane injury,and radial head fracture.The mechanism of injury is the transmission of violence to the wrist from the ulna to the proximal end when the elbow joint is valgus and the forearm is pronated.In that situation,first destroy the lower ulnar-radial joint,then pass through the interosseous membrane,and finally reach the radial head.But in our case,the elbow was injured first and then transmitted to the distal end.And there was no dislocation of the lower radioulnar joint in our case.Therefore,in terms of clinical manifestations and possible injury mechanisms,the cases we reported are different from Essex-Lopresti injury.

Figure 4 The schematic diagram of fracture.(A) the schematic diagram of Monteggia;(B) Galeazzi fracture;(C) proximal radius fractures associated with radial head dislocations reported in this case.

Figure 5 The possible injury mechanism of this case. The possible injury mechanism was that the force acting on the elbow joint caused the annular ligament anchor tear,causing dislocation of the radial head,and then the force was transmitted to the distal end,causing partial tearing of the interosseous membrane.The radius shifts away from the ulna.The body flips during the injury,causing the radius to collide with the humerus,resulting in a proximal radius fracture.

Diagnosis of proximal radius fracture combined with dislocation of the radial head is not difficult,but this type of fracture is rare and easily missed.In our case,we missed the diagnosis before the operation,mainly because we had not encountered similar cases before and lacked relevant clinical experience.In order to avoid the recurrence of this situation,a detailed medical history must be asked.If the patient has an elbow injury,it may be necessary to consider this situation.And it is best to do X-ray film of elbow flexion before operation,and three-dimensional computed tomography (CT) of elbow joint.If the annular ligament avulsion injury is not repaired during the operation,the radial capitulum will be repeatedly dislocated after the operation.

Dislocation of the radial head is common in children under four years old because the immature annular ligament can easily lead to the prolapse of the radial head.This patient is 35 years old.By reviewing the literature,we found that there are just a few reports of similar cases [4-8].The age of the patient ranges from 4 to 39 years old.In the 4 cases reported in the literature,the radius was internally fixed with intramedullary nails or steel plates,but the annular ligament was not repaired.Three of them said that the elbow joint was well set after the operation,and once claimed that the radial head dislocation was found four days later.In our case,the patient’s preoperative elbow joint front and lateral radiographs did not show dislocation of the radial head,because after a fracture of the proximal radius,although the annular ligament tendon point was torn,the fractured end of the proximal radius was lost to stress.However,the radial head was not significantly displaced under the restriction of the surrounding joint capsule and muscles,and no dislocation of the radial head was found before the operation.This is the reason for the missed diagnosis of radial head dislocation before surgery.After the radius was repaired during the operation,the continuity of the radius was restored,and the distal stress was retransmitted to the proximal end of the radius,causing the radial head to dislocate under the flexion of the elbow joint.The radial head was observed to be dislocated during intraoperative C-arm machine fluoroscopy.Therefore,passive movement during the operation is critical for detecting radial head dislocation.If dislocation of the radial head did not find during the operation,there may be repeated dislocations of the radial head after the operation,scar tissue formed at the damaged area of the annular ligament,and the remaining part may shrink and be difficult to identify.In the elbow joint,the ligament that fixes the proximal radioulnar joint is called the lateral collateral ligament complex,the superficial layer is the superficial lateral ulnar collateral and radial collateral ligament,the middle layer is the annular ligament,and the innermost layer is capsular [9,10].The annular ligament plays the most important role in radial head stability.The annular ligament’s anchor point is the sigmoid notch of the ulna,which surrounds the radial head [11].It serves to fix the proximal radioulnar joint during the pronation and supination of the forearm.Dislocation of the radial head is more common in Monteggia fractures because of the immature of the annular ligament [10].In this case,we found an avulsion of the annulus ligament during the operation,so a threaded anchor was used to fix the annulus ligament at the ulnar notch.The patient had good mobility after the operation,and no dislocations happened again.During the operation,it is critical to obtain a precise diagnosis.Intraoperative repair is simpler and more effective than later repair.Repairing the annular ligament with a threaded anchor can achieve a good reconstruction effect.

Conclusion

Here,a case about radius fractures combined dislocations of the radial head has been reported.For such patients,a three-dimensional CT examination of the elbow joint before surgery should be done,which can help reduce missed diagnoses.During the operation,the annular ligament should be explored,and any damage should be repaired.

Recommendation

When we receive patients,we must carefully ask for medical history,which has the most important clue.After fracture reduction,X-rays of adjacent joints must be detected during surgery.