9 Autologous Cartilage Implantation: Cartilage Biopsy, Cartilage Implantation

Lars Peterson

Patient Presentation and Symptoms

Patients present with a history of trauma, repeated trauma, or microtrauma that could have occurred far back in time or without a known cause. The main complaints are pain and locking, catching or crepitations on activities, and swelling, stiffness, and pain after activities.

Indications

Autologous chondrocyte transplantation (ACT) [autologous chondrocyte implantation (ACI)] is indicated in physiologically young patients with full-thickness condral injuries, including osteochondritis dissecans, to the condyles or the trochlea of the femur and patella. The injury should be unipolar grade III or IV Outerbridge classification and between 10 and 35 mm in diameter, with the reciprocal articular surface having no more than grade I or II Outerbridge classification chondromalacia.

Contraindications

1. Osteoarthritis, i.e., bipolar or generalized disease
   
2. Rheumatoid arthritis and other systematic joint diseases

Physical Examination

1. Local joint tenderness, swelling, or effusion
   
2. Range of motion (ROM) normal or with some restriction, pain at hyperextension or hyperflexion
   
3. Crepitations with or without pain on flexion and extension against resistance
   
4. Genu varum/valgum
   
5. Patella malalignment or instability
   
6. Ligament instability

Diagnostic Tests

1. Arthroscopic assessment with probe
   
2. Standing x-ray with extended knees and in 45-degree flexion is a useful screening tool for patients with joint space narrowing, osteophyte formation, subchondral bone sclerosis, or cyst formation.
   
3. X-ray with hip-knee-ankle axis to decide angle of varus or valgus
   
4. Magnetic resonance imaging (MRI) with and without gadolinium

Special Considerations

1. Is the defect, especially the posterior extent, accessible for surgery in open arthrotomy?
   
2. Is the lesion contained or uncontained?
   
3. Ligament insufficiency should be diagnosed and corrected.
   
4. Tibiofemoral malalignment may need correction with proximal tibial or distal femoral osteotomy.
   
5. Patellofemoral malalignment or instability may need correction.
   
6. Osteochondritis dissecans (OCD) or osteochondral fractures with bony defect deeper than 8 to 10 mm may need concomitant bone grafting.
   
7. Intralesional osteophytes need to be gently trapped down to the level of the surrounding subchondral bone or carefully abraded.

Preoperative Planning and Timing of Surgery

For cell culturing, at least 2 weeks are required between arthroscopy and cartilage harvesting and chondrocyte transplantation.

Special Instruments

For the Biopsy

1. Arthroscopic probe
   
2. Ring curette or sharp gouges
   
3. Grasper

For the Chondrocyte Transplantation

1. Ring or closed curette
   
2. Periosteal elevator
   
3. No. 15 knife blade
   
4. Nontoothed forceps
   
5. 5-0 or 6-0 resorbable suture on a P-1 cutting needle immersed in sterile mineral oil or glycerine
   
6. Fibrin sealant.
   
7. Flexible 18-gauge 2-inch angiocath

1. Stability testing
   
2. Tourniquet controlled bloodless field
   
3. Arthroscopic probing and evaluation of all the articular surfaces, the menisci, the synovial lining, the cruciate ligaments, and any fragments or loose bodies present; assessment of the depth, size, and location of defect, as well as the opposing surface
   
4. Loose bodies and fragments, if present, should be removed before the harvesting of cartilage.
   
5. Cartilage harvesting: Approximately 200 to 300 mg cartilage is needed: that is a cartilage surface of approximately 5 by 10 mm. With a ring curette or sharp gouges full-thickness cartilage down to bone is biopsied (Fig. 9–1). The most common harvest site is the proximal medial edge of trochlea. The lateral edge can also be used. If patella overhangs both edges, the lateral intercondylar notch may be used, as long as the patella during flexion does not load the area.
   
6. Meniscus lesions, if present, should be treated after the harvesting

Chondrocyte Transplantation

1. Tourniquet controlled bloodless field
   
2. Medial or lateral parapatellar arthrotomy; adequate exposure of the defect is crucial.

Debridement of Defect

1. Knife with No. 15 blade is used to incise in normal cartilage and excise any damaged cartilage with a curette and periosteal elevator. Try to achieve as symmetric a defect as possible, with vertical edges down to the subchondral bone plate (Figs. 9–2 and 9–3). It is important to maintain an intact subchondral bone plate so that no subchondral bleeding occurs.
   
2. The length and width of the debrided defect are measured. A template of the lesion is made of aluminum foil or sterile paper (Fig. 9–4).

Periosteal Harvest

1. A periosteal flap 2 mm longer and wider than the template is then harvested (Fig. 9–5). The easiest location for harvesting is the proximal medial tibia distal to the pes anserinus, which is reached through a separate incision.
   
2. Gently, remove all fat and fibrous tissue down to the periosteum, incise the periosteum down to bone using a No. 15 blade, use a small sharp periosteal elevator and a nontoothed forceps to carefully remove the periosteum from the bone. Other harvest sites are the medial and lateral femoral condyles proximal to the articular surface or the distal femoral shaft.

Periosteal Flap Suturing

1. The periosteal flap is placed onto the defect with the cambium layer facing toward the subchondral bone (Fig. 9–6).
   
2. Suturing is done with 5-0 or 6-0 resorbable sutures in an interrupted and alternating fashion with the knots being on the side of the periosteum.
   
3. Place the sutures with 4- to 5-mm intervals. If the lesion is uncontained, suturing to synovium or small drill holes through the bone is possible.
   
4. The most superior aspect of the periosteal flap is left open. Use fibrin sealant to seal the intervals between the sutures (Fig. 9–7).

Testing Watertightness

1. Watertight integrity is tested with a tuberculin syringe with a plastic 18-gauge 2-inch angiocath filled with saline (Fig. 9–8).
   
2. When gently filling the defect any leakage can easily be seen around the periphery of the repair. If necessary add another suture and check again. The saline is then reaspirated.

Cell Implantation

1. Once this is acquired the chondrocytes are implanted with a tuberculin syringe with a flexible 18-gauge 2-inch angiocath (smaller gauges will damage the cells). The angiocath is placed through the superior opening and deep into the defect. As the angiocath is withdrawn the cells are gently injected until a meniscus comes to the opening. Sutures are used to close the remaining opening, and it is then sealed with fibrin sealant.
   
2. The wound is then closed in layers. Intraarticular drains are not used because they might harm the periosteal flap or suck out the cells. When a drain is needed, it should be without suction.

Related posts:

The Subvastus Approach Meniscal Injuries/Repair: Staples Arthroscopic Lateral Retinacular Release Meniscal Injuries/Repair: BioStinger Total Knee Replacement: Pearls of Posterior Cruciate Ligament Substitution Closing Wedge Proximal Tibial Osteotomy

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