Osteochondritis Dissecans of the Capitellum: Arthroscopic Microfracture

Abstract

Background:

Osteochondritis dissecans of the capitellum is a focal injury to the articular cartilage and subchondral bone observed in young athletes. This can cause activity-limiting pain, intra-articular loose bodies, and limited range of motion.

Indications:

Stable lesions identified early with minimal symptoms can be managed nonoperatively. Indications for surgical management include unstable lesions, loose bodies, mechanical symptoms, and stable lesions that failed 6 months of nonoperative treatment. A range of surgical options have been advocated—including arthroscopic versus open loose body removal, fracture fixation, drilling, microfracture, osteotomy, osteochondral autograft or allograft transplantation. Arthroscopic microfracture offers a minimally invasive approach.

Technique Description:

After diagnostic elbow arthroscopy, the capitellar lesion is identified and inspected. Unstable cartilage is debrided, and the bony bed is prepared. A 1.1-mm (0.045”) K-wire is then used along with a blunt-tipped 2.4 mm anterior cruciate ligament guide pin sleeve to perforate the subchondral bone spaced 2 mm apart throughout the base of the lesion.

Results:

Arthroscopic microfracture can relieve the patient's pain, improve motion, remove loose bodies, and initiate fibrocartilaginous filling of the defect.

Discussion/Conclusion:

Arthroscopic microfracture for osteochondritis dissecans of the capitellum offers a minimally invasive approach with good to excellent outcomes.

Patient Consent Disclosure Statement:

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Graphical Abstract

This is a visual representation of the abstract.

Video Transcript

Background

Elbow pain in a young athlete can be difficult to evaluate and manage. Osteochondritis dissecans of the capitellum is a rare condition that can cause pain, mechanical symptoms, and restricted range of motion. It is observed in skeletally immature athletes and is hypothesized to result from repetitive compression of the radiocapitellar joint. This results in focal damage to the articular cartilage and underlying subchondral bone. This is differentiated from Panner Disease, which is an osteochondrosis of the entire capitellum, is atraumatic, and affects younger patients. ⁷

Indications

Here we present the case of an 11-year-old right-hand-dominant boy with diffuse right elbow pain during baseball play for 4 months. Focused examination of the right elbow demonstrated a normal appearance without edema. He was nontendering at the olecranon, medial epicondyle, lateral epicondyle, and radiocapitellar joints. His active and passive range of motion was 20° to 140°, with a block at full extension. He was neurovascularly intact, and his medial and lateral elbow ligaments were stable to stress testing.

Radiographs were obtained of the right elbow, including anteroposterior, oblique, lateral, and distal humeral axial views. These demonstrated a skeletally immature individual with osteochondritis dissecans of the capitellum with concern for an intra-articular loose body. A computed tomography (CT) scan was obtained to better characterize the bony anatomy of the elbow. CT demonstrated osteochondritis dissecans of the capitellum. A magnetic resonance imaging of the right elbow without contrast was also obtained to evaluate the articular cartilage and other structures about the elbow. This demonstrated osteochondritis dissecans of the capitellum measuring 10 × 11 mm, with subchondral bright T2 hyperintensity, consistent with an unstable lesion and a loose body.

He was diagnosed with osteochondritis dissecans of the capitellum. This was an unstable lesion in a skeletally immature patient with a lack of 20° of extension and intra-articular loose bodies.

The goals of treatment are to preserve healthy articular cartilage, allow for full elbow range of motion, resolve pain, and maintain a stable elbow joint. Nonsurgical treatment is generally recommended for early-grade lesions with stable articular cartilage and subchondral bone and typically consists of rest from aggravating activities for several weeks, followed by a gradual return to sport at 3 to 6 months. Surgical management is considered for unstable lesions, loose bodies, mechanical symptoms, and stable lesions that have failed 6 months of nonoperative treatment. There are a variety of surgical treatments available—including arthroscopic versus open loose-body removal, fracture fixation, drilling, microfracture, osteotomy, and osteochondral autograft or allograft transplantation. Due to the unstable nature of the lesion, limited range of motion, skeletal immaturity, and the size of the defect, we elected to proceed with arthroscopic debridement, loose-body removal, and microfracture.^2,7

Technique Description

The patient was positioned supine, with a mechanical arm holder secured to the head of the bed to maintain the arm's position throughout the case. The arthroscopic video screen is positioned over the patient, and arthroscopic instruments are placed on a Mayo stand over the patient's waist. Organizing the operating room table before the case begins helps ensure all required instruments are available and easily accessible. These include 3, 4.5, and 5–mm metal cannulas, a power driver, 1.1-mm (0.045”) K-wire, and 2.4-mm anterior cruciate ligament (ACL) guide pin sleeve.

Bony landmarks were identified and marked—including the radial head, lateral epicondyle, olecranon process, and medial epicondyle. The ulnar nerve was identified and marked. Planned portal sites were then identified and marked—including the direct lateral, proximal lateral, distal ulnar, posterolateral, posteromedial, and anteromedial. ⁴

The upper extremity was exsanguinated, and the tourniquet was inflated to 250 mmHg. To begin, an 18-gauge spinal needle was inserted through the direct lateral portal, and the elbow was insufflated with 30 mL of arthroscopy fluid. Next, a second 18-gauge spinal needle was inserted through the proximal-lateral portal. Outflow of arthroscopic fluids confirms the correct intra-articular positioning. A nick-and-spread technique was then used to create a portal, and a 4.5-mm cannula was placed, followed by a 3-mm arthroscope. An anteromedial portal was then made as a working portal. An arthroscopic shaver was used to perform a synovectomy for visualization and evaluation of the anterior elbow. An intra-articular loose body was identified and removed.

A cannula was kept in the proximal lateral portal throughout the case to allow for access to the anterior joint as needed. A direct lateral portal was made, initially localized with an 18-gauge spinal needle, followed by the 3-mm arthroscope. A distal ulnar portal was then made after localization with a spinal needle. Flexing the elbow to 90° exposes the capitellum for evaluation and treatment.

With the arthroscope in the direct lateral portal, the distal ulnar portal was used as the working portal. The synovium was debrided with an arthroscopic shaver. The capitellar lesion was identified and inspected with a probe. The lesion measured approximately 10 × 10 mm and had unstable cartilage flaps. The loose flaps of cartilage were then debrided with the shaver. Care was taken to ensure a stable border was established. The bony base of the defect was then burred to generate a healthy bleeding surface. A blunt-ended 2.4-mm ACL guide pin sleeve was then inserted into the distal ulnar portal. Using a 1.1-mm (0.045”) K-wire on a wire driver, perforations were made through the subchondral bone in the bed of the defect, approximately 6 mm in depth, spaced 2 mm apart. This process was repeated to microfracture the entire lesion. Fluid pressure was temporarily reduced to confirm extravasation of marrow contents from the microfracture sites.

To complete the elbow arthroscopy, the arthroscope was kept in the direct lateral portal and was driven into the posterior compartment. A posterolateral portal was created after localization with a spinal needle, followed by a posteromedial portal created under direct visualization, taking care to protect the ulnar nerve. A shaver was used to debride synovium, and a loose body was identified and removed. The portals were closed with nylon, and sterile dressings were applied. The patient was placed into an elbow range of motion brace locked at 90°.

The patient was sent for physical therapy to begin within 1 week postoperatively. Activity is progressed as each stage is completed. A sport-specific interval training program is started at 9 months postoperatively. Athletes are cleared to return to sports once they have full range of motion, pain resolution, and have completed their interval training program.

Some helpful tips include ensuring the operating room back table has all the required equipment and is organized. This makes switching portals and completing the case steps easier and smoother. Visualization of intra-articular structures, including the capitellum, can be greatly improved with small changes in elbow flexion or extension, as needed. Occasionally, moving the arthroscope to the direct lateral portal can provide a more useful viewing perspective. Additionally, the smaller 3-mm cannula lacks an integrated fluid inflow. Therefore, the inflow of arthroscopic fluid must come from an alternative portal and cannula. Finally, it is critical to ensure the bed of the lesion is fully debrided of scar tissue and nonviable bone to allow for postoperative healing.

Results

Outcomes research has mostly been limited to retrospective studies with short- and medium-term follow-up. Many of these studies have found that patients have high rates of improvement in pain and range of motion. Rates of return to sport have been as high as 80%.^1,3,6 Intraoperative complications associated with elbow arthroscopy are rare and include transient nerve palsy, limited range of motion, and superficial wound complications. ⁵ Long-term success of capitellar microfracture is not well studied but includes risks of arthritis, loose bodies, pain, and inability to return to full activity.^2,7

Discussion/Conclusion

Osteochondritis dissecans of the capitellum is a focal injury of young athletes. Clinical decision-making is guided by lesion stability, skeletal maturity, presence of loose bodies and mechanical symptoms, and motion. Treatment can be nonoperative for early, stable lesions; however, operative intervention is generally indicated for unstable lesions, loose bodies, mechanical symptoms, and stable lesions that have failed 6 months of nonoperative treatment. There are many treatment options available based on the individual clinical scenario. Arthroscopic microfracture offers a minimally invasive approach with good to excellent outcomes.