Osteochondral autograft for the treatment of focal cartilage lesions

OSTEOCHONDRAL AUTOGRAFT FOR THE TREATMENT OF FOCAL CARTILAGE LESIONS ANDREW S. LEVY, MD

Osteochondral autograft transplantation is an acceptable treatment option for symptomatic chondral lesions of the femur. Animal and human studies have showed cartilage viability at 2 years transplantation. Clinical evidence shows an overall 85% average rate of efficacy in diminishing the pain and swelling associated with chondral lesions. Clinical results are best optimized by using this technique for small focal lesions (< 2 to 2.5 cm2). KEY WORDS: cartilage, femur, knee Copyright © 2001 by W.B. Saunders Company

Analytical studies have shown that both blunt and shear stress are manifest at the tidemark that separates the calcified and uncalcified cartilage in the articular surface. ~ This "essential lesion" of articular cartilage damage has subsequently been substantiated by cadaver and animal studies. 2,3 The rational behind osteochondral transfer is to replace the damaged cartilage bone unit with a healthy one. The short-term goal of such a procedure is relief of the symptomatology of chondral lesions and subsequent improvement in function. In 1908, Judet 4 first reported on the use of autogenous osteochondral grafting. He reported on the transplantation of osteochondral fragments after trauma and noted clinical relief of pain. In 1961, Pap and Krompecher 5 published canine data that showed that cartilage transplanted on bone less than 5 mm survived greater than 2 years without deterioration. Similar data was published by Campbell et al" in 1963 that showed that 1- to 2-cm osteochondral plugs with less than 5 m m bone survived greater than 1 year. Other authors further showed that bone, not cartilage, is replaced in whole joint grafts. 7,'4 Ill 1985, McDermot et al L' confirmed the efficacy of wafer grafts (2 to 3 mm of bone) in osteocartilage replacement and noted "the fate of the bone portion of graft directly effects the fate of cartilage."" The recent enthusiasm for osteochondral grafting of cartilage lesions can be traced to the development of instrumentation that allows for careful harvest and placement of graft to fill focal lesions. In 1997, H a n g o d y et al ~" reported on 102 cases of "mosaicplasty" by using 4.5-mm wide and 15-mm deep cylinders obtained from the medial and lateral trochlea. At 32-month follow-up, 102 of 107 were rated good to excellent on HSS scoring. "~,~ By using a similar tect~nique, other investigators have reported 86% improvement by using 15-ram deep grafts. 12.13 Several

From Overlook Hospital, Summit, NJ. Address reprint requests to Andrew S. Levy, MD, MAC 409, Overlook Hospital, 33 Overlook Rd, Summit, NJ 07901. Copyright © 2001 by W.B. Saunders Company 1048-6666/01/1102-0008535.00/0 doi: 10.1053/otor.2001.21772

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investigators used plugs 8-mm deep and reported additional clinical outcomes of 86% improvement in pain and activity level. ~4.'5

INDICATIONS FOR OSTEOCHONDRAL AUTOGRAFT TRANSPLANTATION Lesion size and location limit tile application of osteochondral autografts. Additionally, the technique is recommended only for focal chondral lesions and not fulminate arthritis. Because of limited donor availability, ideal lesions should be less than 2.5 cm 2 in area. Grafts must be placed perpendicularly into the recipient site, which makes application virtually impossible for posterior condylar and tibia lesions. Although some investigators have reported use on the patella, this is not recommended because of cartilage thickness mismatch (5 to 10 m m for patella and 2 to 3 mm for graft). Consequently, the preferred lesion is on the femoral condyle in the anterior or middle third. Trochlea lesions are potentially treatable with this tectmique, but extra care must be taken to match the curvature of the groove.

CONSISTENT TECHNIQUE

OSTEOCHONDRAL

REPAIR

The Consistent Osteochondral Repair (COR) System was introduced in 1997 by Innovasive Devices (Mitek Corp, Norwood, MA). This system represents 1 of 3 on the market that are designed to produce accurate and reliable osteochondral transfer. The systems differ on their technique of harvest, depth of harvest, and mechanism for ease of graft delivery. No system has produced a shown clinical outcome improvement over the other systems available. All differences in equipment or technique should be considered as relative advantages or disadvantages and surgeons should decide accordingly. S t e p I - - P r e p a r a t i o n of C h o n d r a l Lesion Once a chondral lesion is identified, it must be debrided to a stable border for all cartilage repair techniques. It has been noted that the initial appearance of the chondral

Operative Techniques in Orthopaedics, Vol 11, No 2 (April), 2001: pp 108-114

r J Fig 1. Use of bent osteotome to debride lesion to stable boarders. Fig 3. Assembly of graft cutter/harvester.

lesion is usually one third of the final size once debrided. 1" Debridement is best performed by using a bent curette or osteotome (Arthrex Inc, Naples, FL). It is important to achieve vertical walls at the edge of the chondral lesion (Fig 1). This is performed to provide stability and prevent synovial exposure of deep chondral layers. Because osteochondral grafting relies on fibrocartilage stimulation to provide "the mortar" around the plugs, punctate bleeding must be achieved at the base of the lesions. This may be performed by a variety of methods including microfracture or limited abrasion. Drilling should be avoided during this step because it can interfere with socket creation. Recipient site sizing is initially performed with calibrated probes to determine overall size. The metal graft impactors are then used to delineate plug size and array. This step can also be used to determine perpendicular alignment of portal and lesion. It is often advisable to resect the ligamentum mucosum and debride the fat pad to maximize exposure and prevent entrapment when delivering graft.

Step I I - - S e l e c t i o n of Donor Site

Although there is no true completely non-weight-bearing articular cartilage of the knee, contact studies have revealed 2 sites with significantly less contact pressure. These include the outer edge of the lateral femoral condyle above the sulcas terminalis and the intercondylar notch (medial and superior aspect). Additionally, notchplasty studies have revealed that up to 8 mm of lateral notch can be removed without significant alteration in patellofemoral contact forces. 17 Lateral femoral condyle donor site can be easily accessed from a standard lateral portal with the leg at or near extension. The intercondylar notch site is best accessed from a standard medial or transpatellar tendon portal (Fig 2). Factors that influence donor site choice include concomitant ACL reconstruction (harvest as part of notchplasty), previous ACL reconstruction (previous notchplasty), size of lesion, donor cartilage thickness, and apparent radius of curvature of recipient site. Step Ill--Graft Harvest The appropriate size cutter (with tooth) is placed on the harvester and introduced into the knee (Fig 3). This is best performed with the plunger fully inserted to prevent sy-

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Fig 2. Notch site for graft harvest.

FOCAL CARTILAGELESIONS

Fig 4. Impaction of graft cutter and harvest via tooth rotation.

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novial tissue from being caught in the cutter during entry into the knee. The plunger is removed and replaced by the anvil for impacting the assembly. The cutter assembly is placed over the desired hyaline cartilage donor site. Care is required to assure that alignment is as perpendicular as possible. This should be checked by visualization around the entire harvesting device. It is important to remember that the use of a 30 ° arthroscope will result is some distortion of perpendicular appearance. The cutter/harvester is impacted to the 8-mm depth by using a mallet (Fig 4). The harvester is then rotated 360 ° so that the cutting tooth scores and cuts the graft 8 mm below the surface. The device is then withdrawn and taken to the back table with the graft held in the cutter. Donor sites may be left open or may be filled with either cancellous bone or a graft substitute. If left open, they are rapidly filled with cancellous bone and are covered with a layer of fibrocartilage.

open end of the clear delivery tube stabilized on the table to prevent loss of graft. The graft is then measured for final determination of obliquity and depth to better prepare the recipient site.

Step IV--Back Table Harvest Assessment Once harvest is complete, the graft/harvest assembly is taken to the back table where the cutter is removed. The graft can then be plunged with a metal plunger into a clear delivery tube (Fig 5). This should be performed with the

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Step V--Creation of Recipient Socket The arthroscope is placed in the contralateral portal to the side the lesion is on. The drill is brought in through the appropriate portal. It is advisable to deliver the drill into the notch region to prevent iatrogenic chondral damage. The drill is positioned as perpendicular as possible to the lesion. Occasionally, a midpatellar portal may be necessitated to achieve perpendicular alignment. In cases of multiple plugs, tile most posterior graft is placed first. Once the location is chosen, the drill nipple is pressed into the subchondral plate to prevent skiving (Fig 6). The recipient site is then drilled so that the flange is equal to the cartilage surface (Fig 7). The drill is removed and the socket is cleaned with a shaver to remove bony debris.

Step VI--Delivery of Graft The clear delivery sleeve holding the graft is placed into tile knee (Fig 8). The sleeve is rotated to align any obliquity

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with the curvature of the stable surrounding cartilage. The graft is gently malleted into position by using a plastic plunger (Fig 9). The graft is delivered so that all bone is below the surrounding cartilage. The sleeve is removed (Fig 10) and final impaction is performed to bring the graft cartilage parallel with the surrounding cartilage (Fig 11). This should be assessed with a probe.

Step VII--Multiple Plugs Multiple small plugs allow better radius curvature matching, but each graft will be weaker in torsional strength and

more susceptible to delamination during impaction. Grafts greater than 8 mm in diameter raise concerns with harvest morbidity and radius mismatch. Consequently, multiple plugs are more commonly used to fill defects. Although multiple grafts can be simultaneously harvested by the experienced surgeon, recipient socket creation and delivery should be successfully completed 1 graft at a time. It is

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FOCAL CARTILAGE LESIONS

Fig 12. Resection of unstable flap on edge of graft.

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Fig 13. (A) Chondral lesion on the lateral femoral condyle (11 mm x 8 mm) after debridement to stable boarders. (B) Chondral lesion on the lateral femoral condyle after first plug placed. (C) Chondral lesion on the lateral femoral condyle with 2 osteochondral grafts in place.

acceptable to partially drill the edge of a placed secure graft, but this should not exceed 90 ° of the circumference of the graft. This could cause destabilization of the neighboring graft.

Technical Pearls 1. Perpendicular is the rule for both harvest and implantation. Graft obliquity results in incongruent transplant that may be proud on 1 side and depressed on the other. 2. Miniarthrotomy does not increase surgical morbidity and can be extremely useful for achieving proper graft orientation and placement for lesions requiring multiple plugs and difficult locations. 3. Excise anterior synovitis and hypertrophic fat pads at the beginning of the case to facilitate visualization and prevent entrapment during graft delivery. 4. Microtap grafts in place to avoid heavy pressure on graft that could cause chondral delamination. 5. Visualize plug before insertion. This allows conformation of actual graft depth before drilling. Clear delivery tubes also allow for assessment of any graft obliquity. In many cases, obliquity of less than 20 ° can be used to match the radius of curvature of the femoral condyle if matched at insertion. 6. Remove unacceptable plugs. Do not accept poorly placed plugs (Fig 12). A sharp osteotome should be used to trim any proud component. In many cases, the resultant 2-mm fibrocartilage rim is acceptable, or ad-

ditional smaller plugs can be used around a plug whose surface has been cut. P o s t o p e r a t i v e Rehabilitation 0-3 Weeks:

3-6 Weeks: 6-9 Weeks: 9-12 Weeks: 12+ Weeks:

Non-weight-bearing: full active/active assisted range of motion; Passive extension: Isometric strengthening; 50% weight-bearing: full range of motion, cycling, short arc quad strengthening; Full weight-bearing: closed chain and eccentric strengthening, stepper, treadmill; Open chain strengthening: activity-specific conditioning; Return to full sports participation.

COMPLICATIONS

Potential early complications include hemarthrosis, persistent effusion, pain, graft fracture, graft delamination, and loose bodies. Avascular necrosis must be considered a risk, particularly if multiple deep (1 to 2 cm) plugs are harvested or deposited. As in most surgical techniques, the best treatment is prevention.

Case 1 This patient is a 34-year-old woman, who was a recreational runner with no acute injury. She began developing

Fig 14. (A) Chondral lesion on the medial femoral condyle (15 mm x 15 mm) after debridement to stable boarders, (B) Chondral lesion on the medial femoral condyle. Osteochondral graft in clear delivery tube during placement. (C) Chondral lesion on the medial femoral condyle after 3 osteochondral grafts placed.

112

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care. At arthroscopy, an l l - m m × 8-mm chondral lesion was identified on the femoral condyle, which was treated by using a 6- and 4-mm plug (Fig 13). By 6 weeks, the patient was pain free and ambulating without a limp. Running resumed at 12 weeks. At 36-months follow-up, she remains asymptomatic.

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pain with running accompanied by occasional swelling• Eventually, symptoms progressed to a point where the pain was constant and toothache in nature and produced a limp. Clinical examination was positive only for tenderness to palpation over the medial femoral condyle at 90 ° flexion. A magnetic resonance image (MRI) was obtained that was negative and she failed 2 months of conservative

This patient is a 26-year-old man who was a driver in a motor vehicle accident. During the accident, he reported banging the knee into the dashboard. Before surgical referral, he had 4 months of conservative care and 2 negative MRIs. The major complaint was of painful popping in the knee as he bent down. Clinical examination revealed tendemess on the femoral condyle with a positive apley grind and crepetence at 45 ° of flexion. Arthroscopy revealed a 15-mm x 15-mm chondral lesion, which was treated by 3 osteochondral plugs (Fig 14). At 2-years follow-up, the patient's only complaint is of mild pain with weather change•

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Fig 16. (A) O s t e o c h o n d r a l grafting pain a n d s w e l l i n g at 2-year f o l l o w - u p . (B) O s t e o c h o n d r a l grafting activity w i t h o u t difficulty at 2-year follow-up. [] , r u n n i n g ; [ ] , j u m p i n g ; [~, stair c l i m b i n g ; D , b e n d i n g / s q u a t t i n g . (C) O s t e o c h o n d r a l grafting n o r m a l gait at 2-year follow-up. (D) O s t e o c h o n d r a l grafting f r e e d o m from t e n d e r n e s s at 2-year follow-up. [ ] , Medial; r~, P a t e l l o f e m o r a l ; rT, Lateral. (E) O s t e o c h o n d r a l grafting f r e e d o m from e f f u s i o n at 2-year follow-up.

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COR CLINICAL STUDIES In a n effort to p r o v i d e c o n t i n u i n g clinical d a t a a n d o u t c o m e a n a l y s i s u s i n g this t e c h n i q u e , a p r o s p e c t i v e m u l t i c e n t e r s t u d y w a s i n i t i a t e d to f o l l o w - u p 200 p a t i e n t s for 5 years. L e s i o n s t r e a t e d a v e r a g e d 143 m m 2 ( r a n g e , 80 to 250 mm2). A total of 81% w e r e p e r f o r m e d a r t h r o s c o p i c l y , w i t h 19% r e q u i r i n g m i n i o p e n t e c h n i q u e (Fig 15). All p a t i e n t s r e p o r t e d i m p r o v e m e n t w i t h the t e c h n i q u e a n d n o d e t e r i o r a t i o n of r e s u l t s h a s b e e n n o t e d at 2 - y e a r f o l l o w - u p (Fig 16).

SUMMARY The l o n g - t e r m g o a l of t r e a t i n g c h o n d r a l l e s i o n s is the p r e v e n t i o n or d e l a y of o s t e o a r t h r i c i c p r o g r e s s i o n . To d a t e , n o t r e a t m e n t o p t i o n for this c o m p l e x p r o b l e m h a s s h o w n a n a b i l i t y to p r e v e n t a r t h r i t i c p r o g r e s s i o n . T h e s h o r t - t e r m goal, h o w e v e r , is to d i m i n i s h s y m p t o m s of p a i n a n d s w e l l i n g a n d i m p r o v e function. A l t h o u g h a d d i t i o n a l l o n g - t e r m f o l l o w - u p is n e e d e d , the e a r l y r e s u l t s p r e s e n t e d so far h a v e s h o w n an o v e r a l l 85% efficacy of o s t e o c h o n d r a l a u t o g r a f t s to d i m i n i s h s y m p t o m a t o l o g y a s s o c i a t e d w i t h focal c h o n d r a l lesions. O s t e o c h o n d r a l g r a f t i n g offers a cost effective, clinically s u c c e s s f u l t r e a t m e n t o p t i o n for s m a l l (<2.5 c m 2) c h o n d r a l l e s i o n s of the knee.

REFERENCES 1. Ateshian GA, Lai WM, Zhu WB, et al: An asymptotic solution for the contact of two biphasic cartilage layers. J Biomech 27:1347-1360, 1994

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2. Radin EL, Ehrlich MG, Chernack R, et al: Effect of repetitive impulsive loading on the knee joints of rabbits. Clin Orthop 131:288-293, 1978 3. Thompson RC, Oegema TR, Lewis JL, et al: Osteoarthritc changes after acute transarticular load. J Bone Joint Surg Am 73:990-1001, 1991 4. Judet H: Essai sur la greffe des tissus articulaires. Comp Rend Acad D Sciences 146:193-196, 600-603, 1908 5. Pap K, Krompecher S: Arthroplasty of the knee. Experimental and clinical experiences. J Bone Joint Surg Am 43:523-537, 1961 6. Campbell CJ, Ishida H, Takashi H, et al: The transplantation of articular cartilage. J Bone Joint Surg Am 45:1579-1590, 1963 7. Entin MA, Alger JR, Baird RM: Experimental and clinical transplantation of autogenous whole joints. J Bone Joint Surg Am 44:1518-1536, 1962 8. Campbell CJ: Tile healing of cartilage defects. Clin Orthop 64:65, 1969 9. McDermot AG, Langer F, Pritzker KP, et al: Fresh small-fragment osteochondral allografts: Long term follow up study on first 100 cases. Clin Orthop 197:96-102, 1985 10. Hangody L, Kish G, Karpati Z, et aI: Arthroscopic autogenous osteochondral mosaicplasty for the treatment of femoral condylar articular defects. Knee Surg Sports Traumatol Arthrosc 5:262-267, 1997 11. Hangody L, Kish G, Karpati Z, et al: Mosaicplasty for timetreatment of articular cartilage defects: Application in clinical practice. Orthopedics 21:751-756, 1998 12. Bobic V: Arthroscopic osteochondral autograft transplantation in anterior cruciate ligament reconstruction: A preliminary clinical study. Knee Surg Sports Traumatol Arthrosc 3:262-264, 1996 13. Morgan CD: OAYS clinical experience and results. 25"~ AOSSM annual meeting. Traverse City, MI, 1999 14. Bradley JP: Osteochondral autograft transplantation clinical outcome study. Proceedings of the Metcalf Memorial Meeting, 1999, Sun Valley, ID 15. Gambardella RA: Autogenous osteochondral grafting: A multi-center review of clinical results, AANA, Vancouver, BC, Canada, 1999 16. Levy AS, Lohnes J, Sculley S, et al: Chondral delamination of the knee in soccer players. Am J Sports Med 24:634-639, 1996 17. Morgan EA, McElroy JJ, DesJardins JD, et al: The effect of intercondylar notchplasty on the patellofemoral articulation. Am J Sports Med 24:843-846, 1996

ANDREWS. LEVY