Creator: Dr. Mohammed hutaif
Published: 2026-04-12T14:24:56.609997+00:00

INTRODUCTION TO CAPITELLAR OSTEOCHONDRITIS DISSECANS

Osteochondritis dissecans (OCD) of the humeral capitellum is a focal, idiopathic alteration of subchondral bone with a risk of secondary damage to the adjacent articular cartilage. It predominantly affects the dominant elbow of adolescent overhead athletes, particularly baseball pitchers and gymnasts. The etiology is widely considered to be repetitive microtrauma secondary to valgus extension overload, which imparts excessive radiocapitellar compressive and shear forces on the vulnerable, tenuous vascular supply of the developing capitellum.

While early-stage, stable lesions in patients with open physes often respond to nonoperative management (strict rest and activity modification), advanced lesions—characterized by articular cartilage fragmentation, loose body formation, or subchondral cyst development—require surgical intervention. For large, unstable, or uncontained defects, Osteochondral Autograft Transfer (OATS) or mosaicplasty has emerged as the gold standard for restoring the articular congruity and biomechanical integrity of the radiocapitellar joint.

💡 Clinical Pearl

The primary goal of surgical intervention in capitellar OCD is the restoration of a congruent, stable radiocapitellar articulation. Failure to address large defects (>50% of the capitellum) can lead to radial head engagement into the defect, resulting in mechanical catching, popping, and rapid progression to early-onset osteoarthritis.

INDICATIONS AND PATIENT SELECTION

The decision-making algorithm for capitellar OCD is dictated by the patient's skeletal maturity, the stability of the lesion, and the size of the defect.

Lesion Grading and Surgical Decision Making

Grade I (Intact Cartilage, Subchondral Changes): Typically managed nonoperatively. If recalcitrant, arthroscopic retrograde or antegrade drilling is indicated to stimulate revascularization.
Grade II (Articular Cartilage Fissuring/Softening): Managed with arthroscopic debridement and microfracture if the lesion is contained and the radiocapitellar articulation remains stable.
Grade III (In Situ Fragment with Sclerotic Margin): If the fragment is large and viable, internal fixation with bioabsorbable screws or darts may be attempted. If fragmented or non-viable, debridement and marrow stimulation or OATS is required.
Grade IV (Loose Body with Empty Capitellar Crater): Requires loose body removal. For small, contained defects, microfracture is appropriate. For large, uncontained defects (>50% of the capitellar width) or those with radial head engagement, OATS is the definitive treatment of choice.

⚠️ Surgical Warning

Microfracture in large, uncontained Grade IV defects often yields structurally inferior fibrocartilage (Type I collagen) that cannot withstand the immense shear forces of overhead throwing, leading to a high rate of clinical failure and inability to return to sport.

PREOPERATIVE PLANNING AND IMAGING

Comprehensive imaging is mandatory for preoperative templating.
* Radiographs: Anteroposterior (AP), lateral, and 45-degree flexion AP views of the elbow. The 45-degree flexion view profiles the capitellum and often reveals the true extent of the OCD lesion, which is typically located on the anterolateral aspect.
* Magnetic Resonance Imaging (MRI): The modality of choice for assessing cartilage integrity, subchondral edema, and the presence of a fluid line behind the fragment (indicating instability).
* Computed Tomography (CT) Arthrogram: Highly sensitive for evaluating the bony architecture, subchondral cysts, and precise sizing of the defect, which is critical for determining the number and size of osteochondral plugs required for mosaicplasty.

SURGICAL TECHNIQUE: OSTEOCHONDRAL AUTOGRAFT TRANSFER

The OATS procedure for the elbow is a technically demanding operation that combines arthroscopic evaluation and preparation with an open or mini-open approach for precise graft insertion.

Phase 1: Diagnostic Arthroscopy and Defect Preparation

Patient Positioning: The patient is placed in the lateral decubitus or prone position with the arm draped over a bolster, allowing free flexion and extension of the elbow. A non-sterile tourniquet is applied high on the brachium.
Diagnostic Arthroscopy:
- Establish a standard anteromedial portal to inspect the anterior joint cavity.
- Evaluate the radiocapitellar joint with the elbow placed near extension to maximize visualization of the capitellum.
- An anteromedial portal can be utilized for probing the defect if necessary.
Lateral Compartment Evaluation:
- Establish a posterolateral portal just lateral to the tip of the olecranon. Pass a small cannula with a blunt obturator into the radiocapitellar area. A 70-degree arthroscope is highly recommended to view the articulation comprehensively.
- Look for a pathological radiocapitellar plica above the lateral gutter. This plica can cause mechanical popping across the edge of the capitellum and must be resected with an arthroscopic shaver.
Defect Debridement:
- Using a spinal needle for localization, establish a direct lateral portal at an angle that allows optimal manipulation perpendicular to the OCD lesion. An accessory lateral portal (1 cm ulnarward or 1 cm distal to the direct lateral portal) may be created if dual access is required.
- Resect the hypertrophic synovium, fat pad, and any plica along the radiocapitellar articulation using a full-radius resector.
- Fully visualize and probe the defect. Assess for continuity, cartilage cap fragmentation, and the percentage of capitellar involvement.
- Debride the defect to a stable, vertical rim of healthy cartilage. Remove all necrotic subchondral bone down to a bleeding, healthy cancellous bed.

Phase 2: Surgical Approaches for Graft Transfer

While arthroscopic-assisted visualization is critical, the actual transfer of the osteochondral graft generally requires an open procedure to ensure precise, flush, and smooth placement of the grafts into the capitellum. Two primary approaches are utilized:

The Posterolateral Column Approach (Mansat and Morrey)

This approach is highly favored for its excellent exposure of the anterolateral capitellum while protecting vital ligamentous structures.
* Make a lateral incision centered over the lateral epicondyle.
* Identify the interval between the anconeus muscle and the extensor carpi ulnaris (ECU).
* Divide the fascia and retract the ECU anteriorly and the anconeus posteriorly.
* Crucial Step: Identify and meticulously preserve the lateral ulnar collateral ligament (LUCL). The anterior joint capsule is separated and incised anterior to the LUCL to expose the radiohumeral joint.

The Posterior Approach

Fully flex the elbow to bring the capitellar lesion into the posterior operative window.
Make a posterior longitudinal skin incision.
Separate the anconeus muscle and the posterior joint capsule to directly view the OCD lesion. This approach is particularly useful for lesions located more posteriorly on the capitellum.

Phase 3: Graft Harvesting (The Knee)

The Osteochondral Autograft Transfer System (e.g., Arthrex Inc., Naples, FL) is utilized for the harvest and transfer of the grafts.
* Donor Site Selection: Grafts are harvested arthroscopically or via a mini-arthrotomy from the ipsilateral knee. The ideal donor sites are the non-weight-bearing regions of the lateral femoral condyle (periphery of the intercondylar notch) or the lateral aspect of the patellofemoral joint.
* Harvesting Technique:
* Determine the size and number of grafts needed using sizers on the elbow defect. Most capitellar defects require one or two grafts ranging from 6 mm to 10 mm in diameter.
* Drive the tubular graft harvester perpendicularly into the donor site.
* Harvest osteochondral grafts of approximately 10 mm to 15 mm in length. Ensure the extraction is smooth to prevent fracturing the subchondral bone or delaminating the cartilage cap.

🔪 Surgical Pitfall

Harvesting a graft that is too shallow (<10 mm) will result in poor bony integration and potential graft subsidence. Harvesting a graft that is too long may cause excessive donor site morbidity and difficulty in seating the graft flush in the relatively small capitellum.

Phase 4: Recipient Site Preparation and Graft Insertion

Socket Creation: Using the recipient graft harvester or a specialized reamer, create the recipient sockets in the capitellar lesion.
Sclerotic Bone Management: If the base of the lesion exhibits severe sclerotic changes, a cannulated drill should be used to drill the base of the socket prior to graft insertion. This provides essential bone marrow stimulation and encourages vascular ingrowth into the autograft.
Depth Measurement: Measure the depth of the recipient socket with a calibrated alignment stick. The depth of the socket must perfectly match the length of the harvested osteochondral graft.
Graft Transfer: Transfer the graft into the recipient socket. The graft must be inserted perpendicular to the articular surface and press-fit into place.
Articular Congruity: The cartilage cap of the graft must sit perfectly flush with the surrounding native capitellar cartilage. A proud graft will cause severe abrasive wear on the radial head, while a sunken graft will fail to restore joint mechanics and lead to step-off forces.

ALTERNATIVE SURGICAL TECHNIQUES

While OATS is the definitive treatment for large, uncontained lesions, the surgeon must be adept at alternative techniques for varying grades of OCD.

Arthroscopic Drilling

For Grade I or firm, stable Grade II lesions with slight softening, arthroscopic drilling promotes revascularization of the subchondral bone.
* Use a 0.062-inch Kirschner wire to perforate the surface.
* A small drill guide must be used to protect the surrounding soft tissue.
* Perforations are spaced 3 mm apart, systematically covering the entire defect.

Internal Fixation

In the rare instance of an unstable lesion (Grade III) that possesses good quality tissue, sufficient size, and adequate subchondral bone, fixation may be attempted.
* The lesion is hinged open, and the fibrous tissue at the base is debrided.
* The base is microfractured to stimulate bleeding.
* The fragment is reduced and secured using headless cannulated bioabsorbable screws or chondral darts.

Microfracture

For Grade II to IV defects that are strictly contained (surrounded by a healthy rim of cartilage) and exhibit a stable radiocapitellar articulation without radial head engagement.
* The defect is debrided to a stable, vertical rim.
* Arthroscopic awls are used to penetrate the subchondral bone plate at 3 mm to 4 mm intervals, allowing marrow elements to fill the defect and form a fibrocartilage superclot.

POSTOPERATIVE CARE AND REHABILITATION

The postoperative rehabilitation protocol is heavily dependent on the specific surgical intervention performed. Strict adherence to the protocol is paramount to ensure graft incorporation and prevent stiffness.

Rehabilitation following Drilling or Microfracture

Phase I (0-6 Weeks): Early, gentle, active-assisted range of motion (ROM) of the elbow is initiated immediately to nourish the developing fibrocartilage and prevent capsular contracture. The elbow is strictly non-weight-bearing. No loading or strengthening exercises are permitted.
Phase II (6-12 Weeks): Once full, painless ROM is achieved (typically around 6 weeks), progressive isometric and isotonic strengthening exercises are introduced.
Phase III (3-4 Months): Return to sport-specific activities and overhead throwing is permitted at 3 to 4 months, provided symptoms have completely resolved, radiographic healing is evident, and symmetric strength has been restored.

Rehabilitation following Osteochondral Autograft Transfer (OATS)

Because OATS involves the transplantation of mature hyaline cartilage and a bony plug, the timeline for biological incorporation is longer.
* Phase I (0-6 Weeks): General ROM is started early to prevent stiffness. A hinged elbow brace may be used to protect the joint from valgus stress. Weight-bearing is strictly prohibited.
* Phase II (6-12 Weeks): Strengthening exercises are initiated at the 6-week mark, focusing on the biceps, triceps, and dynamic stabilizers of the elbow (flexor-pronator mass).
* Phase III (4-6 Months): Return to high-impact activity and competitive pitching is delayed until 4 to 6 months postoperatively. This allows adequate time for complete bony incorporation of the osteochondral graft, which should be confirmed via follow-up MRI or CT if clinically indicated.

CLINICAL OUTCOMES AND EVIDENCE-BASED LITERATURE

The efficacy of OATS for advanced capitellar OCD is well-supported in the orthopedic literature, particularly for high-demand overhead athletes.

Tsuda et al. demonstrated the utility of arthroscopic-assisted visualization combined with open osteochondral transfer, proving its efficacy even in non-athletic populations suffering from advanced OCD.
Iwasaki et al. utilized the posterolateral column approach (Mansat and Morrey) to perform mosaicplasty on eight competitive baseball players. At a 24-month follow-up, seven of the eight patients achieved good-to-excellent results. Utilizing the rigorous Timmerman and Andrews scale, patient scores improved dramatically from an average of 140 to 183 (out of a maximum normal score of 200).
Yamamoto et al. reported on a 2-year follow-up of 18 teenage baseball players who underwent OATS for advanced OCD (nine with Grade III lesions, nine with Grade IV lesions). The results were highly favorable: six of the nine Grade III patients and eight of the nine Grade IV patients successfully returned to their previous levels of competitive sports.

💡 Clinical Pearl

Yamamoto et al. noted that in three patients with massive Grade IV lesions and exceptionally wide defects, follow-up MRI showed persistent evidence of articular irregularities. Despite this, at short-term follow-up, these lesions—which are subjected to immense compression and shear forces from pitching—were considered satisfactorily treated, allowing the athletes to function without debilitating pain. This underscores that while perfect radiographic restoration of massive defects is challenging, the clinical and functional benefits of OATS remain superior to alternative salvage procedures.

CONCLUSION

Osteochondral Autograft Transfer represents a critical, joint-preserving surgical technique for the management of advanced, uncontained osteochondritis dissecans of the capitellum. By meticulously adhering to the principles of precise graft sizing, perpendicular harvest and insertion, and rigorous postoperative rehabilitation, orthopedic surgeons can reliably restore radiocapitellar congruity. This sophisticated intervention not only halts the progression of early-onset osteoarthritis but consistently allows young, high-demand athletes to return to their peak level of performance.

Authoritative Medical Review

This academic synthesis is based on established protocols from Hutaifortho's Operative Orthopaedics and has been medically reviewed by Prof. Dr. Mohammed Hutaif, Consultant Orthopedic & Spine Surgeon. It is designed to assist orthopedic residents, fellows, and practicing surgeons in surgical preparation and board reviews (AAOS, FRCS, Arab Board).

Clinical Disclaimer: The surgical techniques, indications, and medical guidance detailed herein are for advanced educational purposes only. They do not supersede institutional guidelines or independent surgical judgment.

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Key Takeaway