Osteochondral Allograft Transplantation for a Cartilage Defect of the Humeral Capitellum

Abstract

Background:

Cartilage defects of the humeral capitellum most frequently present as osteochondritis dissecans (OCD) in young overhead athletes, such as baseball players. Historically, surgical options have included debridement, marrow stimulation, and osteochondral autograft transplantation. Fresh osteochondral allograft (OCA) transplantation comprises an additional treatment option that can structurally restore osteochondral defects and has demonstrated satisfactory outcomes without the donor-site morbidity associated with osteochondral autograft transplantation.

Indication:

OCA transplantation provides structural restoration of the articular surface and can be used for large (>1 cm diameter) lesions not amenable to refixation. Additionally, OCA transplantation can address both chondral and subchondral pathology and is suited for the treatment of failed previous surgical interventions, such as debridement or marrow stimulation.

Technique Description:

Following diagnostic arthroscopy, an anconeus splitting mini-open approach was performed to expose the capitellar defect. The defect was measured to be 10 mm, and a central guide pin was placed. A 10-mm reamer was used to prepare the defect bed to a depth of 8 mm. An OCA plug was then cut from a fresh femoral hemicondyle to match the prepared defect. The graft was soaked in bone marrow aspirate concentrate harvested from the iliac crest, and the plug was then inserted into the defect and tamped to be concentric with the surrounding articular cartilage.

Results:

OCA transplantation of the capitellum allows for the restoration of the articular surface with a structural graft and can be used for large defects and revision cases. While OCA transplantation is well described in the knee with long-term efficacy, the application of this technique to the capitellum is relatively recent. Recent case series for the capitellum have displayed significant improvements in patient-reported outcome measures and predictable return to sports.

Discussion/Conclusion:

OCA transplantation for the humeral capitellum provides an effective treatment option for large, unstable cartilage lesions not amenable to refixation. The procedure allows for restoration of the articular surface and can provide improvements in pain and function as well as return to sport.

Graphical Abstract

This is a visual representation of the abstract.

Video Transcript

The following is a video demonstrating osteochondral allograft (OCA) transplantation for a cartilage defect of the humeral capitellum.

The following are our disclosures.

In this video, we will discuss the background for osteochondral defects namely osteochondritis dissecans (OCD) of the humeral capitellum. We will discuss outcomes of OCA transplantation, and then we will go through preoperative planning, patient positioning, intraoperative procedural steps, surgical pearls and pitfalls, and then finally the references for our technique and outcomes.

Focal chondral defects comprise localized damage to the articular cartilage which, depending on its severity, may affect the underlying bone as well, thus manifesting an osteochondral defect. These defects can lead to painful limitations to sports and daily activities, and their etiologies include OCD, the subject of the current technique video, as well as avascular necrosis, trauma, and others. Nonoperative management of lesions with persistent symptoms may lead to poor outcomes and generalized joint degeneration.

Capitellar chondral defects are defects of the capitellum, which are often associated with overhead activities, such as baseball and gymnastics. Biomechanically, this makes intuitive sense given that the greatest force on the radiocapitellar joint occurs at the late cocking phase of overhead throwing, thus establishing the pathomechanics with overhead throwing activities. This may also be part of a greater syndrome, namely valgus extension overload syndrome, which also places greater stress on the radiocapitellar joint itself.

OCD of the capitellum treatment options include conservative therapy; biologic injections, such as platelet rich plasma (PRP); surgical debridement, fixation, loose body removal; as well as concurrent marrow stimulation; and treatment of cartilage defects with either osteochondral autograft transplantation or OCA transplantation.

Indications for treating capitellar defects with OCA transplantation include failed prior conservative or surgical therapy, as well as primary treatment with osteochondral allograft for unstable, larger, full thickness lesions of the capitellum which are >1 cm in diameter, associated with loose bodies which are not amenable to refixation, and also defects that are osteochondral in nature, namely they involve the subchondral plate as well.

In terms of the current case, our patient’s history is that of a 14-year-old tennis player with 2 years of intermittent pain and right elbow locking. The patient had previously failed extensive conservative management and did undergo a previous surgery, which he sustained temporarily relief after a capsular release, loose body removal, and injection of bone marrow aspirate (BMAC)

His initial magnetic resonance imaging (MRI) demonstrated a capitellar lesion with subchondral edema, as well as associated loose bodies, and his initial arthroscopic surgery demonstrated a 10 mm by 10 mm loose body with an associated International Cartilage Repair Society (ICRS) grade 4 defect bed of the capitellum.

Following the patients first arthroscopy, he attempted to return to tennis. However, within months he had recurrence of pain, which now limited his sports participation, as well as overhead serving.

Repeat MRI demonstrated persistence of the patient’s capitellar defect with associated subchondral edema and no associated loose bodies. Given extensive postoperative physical therapy without improvement, the decision was made to utilize osteochondral allograft as a salvage treatment with concurrent bone marrow aspirate concentrate to help improve the biologic incorporation of the allograft.

Preoperative interview:

“Your pain is largely in this area right here, is that where it is?” “Yes.”

“And are you getting any locking or catching or just pain with loading?” “Just pain.”

“And your goal is to play competitive tennis, but you are having difficulty doing so because of the pain in here?” “Yes.”

“Okay, great. Thank you.”

The case began by using a bone marrow aspirate harvest from the ipsilateral iliac crest as the operative upper extremity. The patient was then placed in lateral decubitus position, and positioning ensured to allow both hyperflexion of the elbow, as well as access to medial, posterior, and lateral aspects of the elbow. The patient then is prepped and draped in standard fashion, and anatomic landmarks are marked including the ulnar nerve.

The elbow is then insufflated through the lateral soft sport with approximately 10 cm³ sterile saline solution, and a proximal anteromedial portal is established ensuring that this is proximal to the medial epicondyle aimed away from the ulnar nerve and anterior to the intermuscular septum.

Subsequently, a posterolateral portal is established 2 to 3 cm proximal to the olecranon and just lateral to the triceps itself. This allows excellent access and visualization to the radiocapitellar joint. Additionally, a mid-lateral portal is created at the soft spot for further instrumentation of the radiocapitellar joint under direct visualization.

After surveying the joint through use of the proximal anteromedial portal, the posterolateral and midlateral portals were used to visualize and subsequently debride the OCD lesion of the capitellum. The decision was made to convert to a mini-open approach in order to perform OCA transplantation. The midlateral portal was used to guide the placement of an anconeus-splitting approach, which came directly upon the defect in a minimally invasive manner and a chandler, army navy, and small Hohmann retractor were placed in order to provide excellent access and visualization of the defect.

The defect was measured under direct visualization and found to be 10 mm in diameter. Subsequently a 10-mm drill was used to drill the defect to 8 mm millimeters in depth. A sizing tube was used to ensure that adequate drilling was performed.

Therein we focused our attention to a femoral hemicondyle on the back table for OCA preparation. An OCA harvester of 10 mm diameter was used to obtain a plug, and subsequently, the allograft was extruded until only 8 mm of allograft remained within the cylinder, such that appropriate depth grafting was ensured.

The graft was irrigated with 3 L of fluid and subsequently soaked in bone marrow concentrate. We subsequently impacted the graft. Following satisfactory graft impaction, we noted excellent concentricity and fill. The elbow was taken through range of motion to ensure smooth tracking. We then irrigated the wound. Hemostasis was obtained, and we closed the wound and fascia in usual fashion.

In terms of outcomes of OCA transplantation of the capitellum, there is overall relatively limited data on patient-specific outcomes. However, limited samples which have been published demonstrate consistent and predictable return to sport, as well as improvement in patient-reported outcome measures.

Our chosen technique has both pros and cons. Pros include avoiding donor site morbidity, such as an osteochondral autograft transplantation. An osteochondral allograft also restores the hyaline cartilage surface, and it can be used as salvage therapy after multiple previous treatment failures.

In terms of cons, there increased cost and difficulties with logistics when using osteochondral allografts. Additionally, allograft transplantation generally requires conversion to open or mini-open approach, and there is limited data on outcomes following allograft transplantation, in the capitellum in particular.

In terms of pearls and pitfalls of this approach, arthroscopy in a lateral position allows for quick and easy transition to a mini-open arthrotomy. We also believe that visualization can be improved with elbow flexion and radial head mobilization.

In terms of pitfalls, excessive graft impaction forces may worsen chondrocyte viability and should be avoided. Similarly, the sizing guide must be placed in perpendicular fashion to the defect prior to inserting the guide pin in order to allow for a well contained and concentric graft placement.

In terms of rehabilitation, patients begin 0 to 90° passive range of motion at week 1, and this is then increased as tolerated. Active-assisted range of motion is began at week 4, and full motion is begun at week 6. By months 3 to 5, patients generally have full and pain-free range of motion, and return to sport is allowed at 4 to 6 months postoperatively, depending on clinical examination.

The following are our references.

We thank you for your time and attention.