Operative management of a shear fracture of the bilateral capitellum: A case report and review of the literature.

Fracture of bilateral capitulum humeri is a very rare injury. We present a case of a 38-year-old woman, affected by a shear fracture of bilateral capitellum after a motorcycle accident. Intervention was carried out through a lateral approach on both sides and direct fixation of the fragment with headless screws. Consolidation was achieved and no signs of avascular necrosis occurred at 24 months of follow-up. The patient returned to her previous activities with no functional limitations. To the best of our knowledge, only four cases are reported describing different types of treatment and postoperative period of cast immobilization. According to our review of the literature regarding capitellar fractures, we preferred an immediate postoperative rehabilitation of the elbow, following the stable osteosynthesis.

Introduction

Fractures of capitulum humeri in the coronal plane are rare injuries, accounting for nearly 1% among all elbow fractures. These injuries usually occur after an axial loading force to the capitellum through the radial head. Bryan and Morrey described three types of capitellar fractures. These fractures were further characterized with respect to the absence (A) or presence (B) of a posterior condylar comminution. X rays in the standard AP and lateral views should be performed including forearm and wrist radiographs for associated injuries; moreover, a CT scan is necessary for a detailed preoperative planning. These fractures often result in significantly high long-term morbidity if the surgical treatment is delayed. Open reduction and internal fixation (ORIF) is mandatory in order to obtain the best restoration of the articular surface and allow an early joint mobilization. The integrity of the lateral collateral ligament (LCL) must be assessed during the surgical exposure and the stability of the elbow joint must be tested during the intervention after proper fixation. An isolated, bilateral shear fracture of the capitulum humeri is an extremely rare event with only four case reports found in literature. Here, we present a case of a bilateral capitellar shear fracture treated with ORIF, reporting the surgical management as well as the clinical and the radiographic outcome.

Case report

A 38-year-old female fell onto both her outstretched hands after a motorcycle accident. Clinical examination at the emergency department in our hospital found diffuse swelling of both elbows, together with intense pain and impairment of any elbow joint motion. Radiographs in the AP and lateral planes showed a bilateral fracture of the capitellum humeri without evidence of elbow dislocation (Fig. 1, Fig. 2a). Subsequent X-rays to the forearm and wrist did not reveal concomitant fractures or distal radio-ulnar (DRUJ) joints. The next day, a CT scan was performed with a 3D reconstruction (Fig. 1, Fig. 2b) in the sagittal and coronal planes for a detailed preoperative evaluation. Both capitellar fractures were classified as type 1A. Type “1” refers to the Bryan and Morrey's classification, describing a shear fracture in the coronal plane involving most of the capitellum and none of the trochlea. “A” type, according to Dubberley et al, refers to the absence of posterior condylar comminution. At the third day after trauma, our patient underwent bilateral same-day surgery (ORIF), simultaneously for both capitellar fractures, by two surgical equips.

Fig. 1

A: Preoperative X-rays of the right elbow in AP and lateral view. The capitular fracture is easily identified on the lateral projection. B: CT 3D scan reconstruction. C: Postoperative X-rays after headless screw osteosynthesis.

Fig. 2

A: Preoperative X-rays of the left elbow in AP and lateral view. B: CT scan and 3D reconstruction. Capitulum humeri in the sagittal and coronal plane. C: Postoperative X-rays.

A lateral approach was performed bilaterally with the elbow already been flexed at 90°. Skin incision began 2 cm proximally to the tip of the lateral epicondyle and extended distally and for approximately 4 cm towards the Lister's tubercle. We used the superficial interval between the extensor digitorum communis and the extensor carpi radialis longus and brevis, as described by Kaplan. At the deep level, we proceeded by splitting the lateral annular ligament complex, remaining anterior to the LCL. No LCL avulsion and/or disruption were detected at any of the two sites. Particular attention was paid in order to preserve the LCL and the posterior interosseous nerve. At this point, there was no need to release the lateral ligamentous complex from the distal aspect of the humerus to achieve a better visualization of the fracture. An excellent exposure of the capitellar fractures was achieved showing no impact and/or fragmentation of the capitulum humeri.

Debridement of the free capitellar fragment was performed, removing any residual fibrous tissue and hematoma. The fragments were reduced in direct visualization, held with a dental pick and then temporally fixed with the guide wires of the mini Acutrac (Acumed, Hillsboro, OR, USA) headless screws. Definitive osteosynthesis from anterior to posterior, with one headless Acutrac mini compression screw was realized at both sites, achieving a stable and anatomical reconstruction of the articular surface with screws buried underneath the cartilage. During the procedure, the tip of a guide wire used for temporary fixation was previously broken and intentionally left into the distal right humerus, resulting in no interference with fracture's definitive osteosynthesis. Upon fixation, elbow joint was tested in varus/valgus stress under fluoroscopy and found to be stable in both sides.

Postoperative radiographic exam confirmed anatomic reduction of the capitellar fractures and the correct hardware positioning (Fig. 1, Fig. 2c). The patient was held in flexion at 90° in a provisionary cast. Starting from the second postoperative day, a functional brace for the elbow was positioned with a free range of motion (ROM) between 100° and 20° of flexion. The hinged brace protected the elbow joint from any varus/valgus deviation stress. No load-bearing or strengthening exercises were allowed until early fracture healing was established, within approximately 2 months after surgery. Upon removal of the sutures at 14 days after surgery, the patient was also allowed to come out of the brace and perform gravity-aided and assisted flexion/extension-supination/pronation exercises of the elbow joint.

Clinical and radiographic evaluation was performed at 1, 2, 3, 6, 12 and 24 months after surgery. At each follow-up ROM in flexion/extension and supination/pronation was recorded. After 6 months and during the final follow-up, the American Shoulder and Elbow Surgeons (ASES) score was also obtained. At the first month flexion/extension range was found to be 100°–5° on the right and 95°–10° on the left. Supination/pronation was measured 120° on the right and 110° on the left elbow. After the second month, the fracture site was considered healed, based on radiographic appearance of the fracture and absence of pain on movement in both sides during clinical evaluation. ROM in flexion/extension was found to be 140°–0° on the right and 130°–0° in the left. Supination/pronation was measured at 180° on both sides. Three months after surgery, there was 145° of flexion with full extension on the right (0°–145°), and 135° of flexion and full extension on the left side (0°–135°) (Fig. 3). No variation was detected for ROM at the 6, 12 and 24 months follow-up and the ASES score resulted 100.

Fig. 3

Functional outcome at three months after surgery for both elbows.

Discussion

Type 1 fractures were found to be the most common (84%) among capitellar fractures. Fractures of the capitulum humeri are difficult to recognize in the AP view and a true Lateral film is essential for diagnosis. Moreover, a CT scan including both a sagittal and a coronal 3D reconstruction, provides more information regarding articular impaction and metaphyseal comminution. Various methods and fixation techniques have been described for capitellar fractures. Closed manipulation and conservative treatment of these injuries has been reported in some case series. This approach has the disadvantage of a long immobilization period that could lead to an incomplete clinical recovery.

ORIF with headless compression screws has shown good to excellent results.3, 4 Despite the fact that closed manipulation and cast immobilization seemed to be criticized, Trinh et al in a systematic review found no statistical difference in the clinical outcome, comparing nonoperative (close reduction and immobilization) and operative management of isolated capitellar fractures. Avascular necrosis (AVN), a degenerative joint disease, and heterotopic ossifications are some of the complications that can occur after surgical treatment of capitulum humeri fractures.3, 5 However, McKee et al found that AVN is uncommon after ORIF of these fractures. In addition, even if AVN occurs, clinical outcome can still be satisfactory.

In the case of a delayed diagnosis associated with a high risk of complete osteonecrosis, excision of the fragment could be recommended. Alternatively, ORIF should be the best option using bone graft augmentation. Humeral shear fractures have been reported by Giannicola et al as a potential pattern of complex elbow instability where eventual associated injuries of the LCL and medial collateral ligament (MCL) should be assessed. In our case, type 1A fractures were exposed with a lateral (according to Kaplan) approach and the LCL was found to be intact. After fixation, stability of both elbows was tested during intervention in varus and valgus stress, with no evidence of any MCL injury. Absence of LCL injuries in our case supports the findings of Mighell et al. In their series, type 1 capitellar fractures were not associated with a LCL injury, contrarily to the type 2 pattern (43% of LCL repaired).

Shear fracture of bilateral capitulum is an extremely rare event. After meticulous research in the English literature, only four cases were identified. Acharya et al reported a case of a bilateral capitellar fracture treated with closed manipulation. Reduction was maintained in a back slab for three weeks, with achievement of union in both sides and a good clinical recovery after seven months of follow up. Schindler first reported a bilateral fracture treated with ORIF, followed by a three weeks immobilization. Fracture healing was completed at two months, but mobility impairment remained extensively in both elbows. Polat et al reported one patient treated with K-wire fixation on the right and a mini screw on the left elbow, followed by cast positioning for seven days. Despite the intensive physical rehabilitation, the desired level of function could not be achieved for the right elbow of the patient. Sturridge et al treated a bilateral capitulum fracture with ORIF, adopting headless screws for fragment fixation. Following two weeks of cast immobilization, the patient was put into hinged braces. Eight weeks after surgery, a 15° extension lag on the right and 30° on the left elbow were detected. Three months after surgery, the patient lacked of 10° extension bilaterally.

In our case, ORIF with headless screws offered a stable fixation to the osteochondral fragment in both sides. Early physical rehabilitation beginning from the second postoperative day was protected with a hinged brace for the first month. Clinical recovery was found more promising in our patient comparing to ROM reported for bilateral fractures by the first three authors.8, 9, 10 In the above mentioned cases, elbow was immobilized for a three-week period and rehabilitation of the joint was unable to restore a complete ROM, even when a stable ORIF was achieved. In the most recent case reported, cast was maintained for two weeks following a bilateral stable osteosynthesis of the capitulum humeri. Eight weeks after surgery, the patient showed a 15° extension lag on the right and 30° on the left elbow. Only at the third year during postoperative follow up, ROM was found to be restored with absolutely no loss of function. Our patient experienced an excellent clinical recovery, based on ROM restore, fracture healing and absence of pain on both elbows, after two months of surgery with full extension and supination/pronation bilaterally. Moreover, having both joints mobilized within the range of a hinged brace offered to our patient absolute independence in daily activities.

In conclusion, in accordance with most of the authors, we believe that ORIF of capitellar fractures adopting headless screws is the best way to achieve a stable and anatomic reconstruction in order to restore an early joint movement. In our opinion, if reduction and satisfactory stability of the fragment is achieved, rehabilitation should be started within the second postoperative day. In the very rare case of a bilateral injury, this concept appears mandatory with the purpose to offer immediate functional autonomy in the patient's daily living activities.