Arthroscopic Allograft Cartilage Transfer for Osteochondral Defects of the Talus

Abstract

Arthroscopic treatment of osteochondral defects is well established but has had mixed results in larger lesions and revision operations. Particulated allograft cartilage transfer may provide an arthroscopic option for lesions that would otherwise have been treated through open approaches or osteotomies. The procedure is performed under noninvasive distraction with standard arthroscopic portals.

Multiple procedures have been described for the treatment of osteochondral defects of the talus.¹ Arthroscopic techniques such as mesenchymal stem cell stimulation (microfracture) have been well studied and have shown good success in smaller lesions. Larger lesions and revision operations are often managed with open procedures such as autologous autograft transplantation, allograft osteochondral transplantation, and autologous cartilage incorporation. There are limited studies on the efficacy of these procedures for larger lesions.2, 3

Particulated juvenile cartilage transplantation is a relatively new option and may provide surgeons and patients with an arthroscopic option for the treatment of larger lesions and revision surgery. Early results have been promising, and the particulated nature of the allograft allows for arthroscopic implantation.4, 5 We describe a surgical technique that allows for a reproducible arthroscopic implantation of particulated juvenile cartilage for osteochondral defects of the talus (Table 1).

Table 1.

Steps

1. Perform diagnostic arthroscopy.

2. Identify and debride lesion.

3. Remove fluid from joint; dry defect.

4. If necessary, pack with bone graft.

5. Lay down fibrin glue.

6. Apply allograft.

7. Lay down second layer of fibrin glue.

NOTE. While the surgeon is preparing the lesion, the assistant can load the allograft into the 4-mm cannula.

Surgical Technique

The patient is placed supine on the operating room table with a small bump under the ipsilateral hip. A tourniquet is placed high on the thigh, and the operative leg is placed into a thigh holder at a height that allows the foot to remain 12 inches off the operating table. The ankle is placed into a noninvasive ankle distractor.

The ankle is insufflated with normal saline solution, and a standard anteromedial portal is made at the level of the tibiotalar joint just medial to the anterior tibial tendon. Under direct visualization and transillumination, an anterolateral portal is made just lateral to the peroneal tertius tendon. Depending on the location of the osteochondral lesion, a posterolateral portal may be necessary to best visualize and prepare the defect. The posterolateral portal is made just posterior to the peroneal tendons.

A diagnostic arthroscopy is performed, and the ankle is evaluated in a systematic fashion (Video 1). The osteochondral defect is identified, loose fragments of bone and cartilage are removed, and a stable rim of cartilage is delineated with a sharp curved curette. The defect is measured with an articulated probe, and the need for bone graft and/or allograft transplantation is determined (Fig 1A).

Fig 1.

Anterolateral views using 30° arthroscope. (A) The osteochondral lesion on the lateral shoulder of the talus is well contained. An arthroscopic probe measures the dimension of the lesion. (B) The osteochondral lesion on the lateral shoulder of the talus is completely dried with 0.25-inch pledgets inserted using arthroscopic graspers.

Once the bed of the lesion is adequately prepared, the fluid is turned off and a dry arthroscopy is performed. A small suction tip is introduced to the ankle to remove excess fluid within the joint (Table 2). The ankle is completely dried with the use of 0.25-inch pledgets attached to arthroscopic graspers (Fig 1B).

Table 2.

Key Points

For the fibrin glue and allograft to set appropriately, all fluid must be removed from the joint.

If the lesion is fully contained, the fibrin glue is placed early, prior to an increase in its viscosity.

If the lesion is uncontained, the glue is placed after it has shown increased viscosity such that it will remain where placed within the ankle.

The juvenile cartilage allograft must be cut into small pieces to fit the 4-mm cannula.

The fibrin glue functions as a sealant to prevent fluid from invading the allograft.

At times, there is a substantial bony defect at the base of the osteochondral defect. If bone graft is required, it is harvested from the proximal tibia using a percutaneous system (Arthrex, Naples, FL). This autologous bone is morselized and packed into a 6-mm cannula (Arthrex).

The DeNovo NT Natural Tissue graft (Zimmer, Columbus, OH) is packed into a 4-mm cannula (Arthrex). If any of the particulated pieces are larger than the cannula, they are recut with a sharp scalpel to fit (Fig 2).

Fig 2.

(A) A 4-mm cannula. (B) The juvenile cartilage allograft cartilage is prepared and needs to be loaded into the 4-mm cannula.

Once the autologous bone graft and juvenile cartilage allograft are prepared, the ankle is re-examined to ensure adequate hemostasis. When necessary, bone graft can undergo impaction grafting into the lesion using the 4-mm cannula and a right-angle probe. The bone graft is packed so that it is level with the surrounding subchondral bone. Bone graft is only used in contained lesions.

An 18-gauge needle is used to place a layer of fibrin glue at the base of the lesion. If the lesion is fully contained, the glue is placed early, prior to an increase in its viscosity. If the lesion is uncontained, the glue is placed after it has shown increased viscosity on the back table such that it will remain where placed within the ankle.

The juvenile cartilage allograft cannula is introduced into the ankle with the opening at the most posterior edge of the lesion (Video 1). The graft is slowly extruded from the cannula such that a column of allograft is seen (Fig 3). The distal aspect of the column is placed into the fibrin glue, and a freer elevator can be used to truncate the column when the entire longitudinal length of the defect is filled. This is repeated until the lesion has been filled with graft. A freer elevator can then be used to shape the graft as appropriate. A second layer of fibrin glue is introduced over the graft to seal it in place. Often, the same vial of glue can be used with a new mixing chamber and 18-gauge needle (Fig 4). The ankle is then left in traction until the glue has set.

Fig 3.

Anterolateral views using 30° arthroscope. (A) The juvenile cartilage allograft is extruded from the 4-mm cannula. (B) The allograft is placed into the lateral shoulder osteochondral defect of the talus.

Fig 4.

Anterolateral views using 30° arthroscope. (A) The lesion on the lateral shoulder of the talus is filled with the juvenile cartilage allograft. (B) The juvenile cartilage allograft is sealed with fibrin glue.

Other procedures can now be performed if necessary. We splint the ankle for 10 days and then begin early active dorsiflexion and plantar flexion. The patient must remain non–weight bearing for the first 6 weeks.

Discussion

Whereas multiple studies have shown that arthroscopic procedures such as mesenchymal stem cell stimulation (microfracture) are successful for smaller osteochondral defects of the talus, few studies have been performed that support arthroscopic options for revision operations or larger lesions. Coetzee et al.⁴ recently published early results of a small cohort of patients treated with particulated juvenile cartilage using a mini-open technique. This early study showed that particulated allograft was a viable alternative to traditional methods of treatment such as microfracture and Osteochondral Autograft Transfer System.

In our arthroscopic series, early procedures were performed with a larger cannula, but the use of a larger cannula was technically more difficult because more graft was introduced into the ankle in a shorter amount of time. After having to remove graft that was not contained within the lesion, we adopted a smaller cannula, which has given us more control during implantation. Loading the 4-mm cannula does take patience and increases the operative time; however, to mitigate this process, we will often preload the cannula while the osteochondral defect is being prepared.

The advantages of this technique are that it can be performed in an all-arthroscopic manner and, when one is well versed in this technique, it can be completed in under 60 minutes. In addition, this technique can be performed concomitantly with other arthroscopic techniques, and if necessary, it does not inhibit the use of open techniques. The disadvantage of the technique is that it requires an assistant and requires traction. Both graft preparation and graft application require assistance. Furthermore, because this technique requires traction, the patient is at risk of all the complications associated with ankle traction. Lastly, although the short-term results are promising, the long-term results of juvenile cartilage transplantation are lacking and future studies are required. In summary, the described arthroscopic technique has allowed us to treat larger lesions and revision lesions in an arthroscopic fashion without the need for open approaches or osteotomies.

Supplementary Data

Video 1

Arthroscopic allograft cartilage transfer for an osteochondral defect of the talus. This patient's right ankle shows a contained lesion about the lateral shoulder of the talus. The lesion is prepared, and an all-arthroscopic technique is used to fill the lesion with juvenile cartilage.