The ideal cartilage repair technique should restore long-term structural and biomechanical integrity of the articular cartilage in a single stage first line treatment.

The ideal repair tissue should be hyaline-like with type-2 collagen and proteoglycan matrix, well integrated to the subchondral plate and edges of the defect. Achieving this is a biological challenge but has the potential to improve symptoms and function and reduce risk of osteoarthritis.

Always remember to treat alignment, meniscal deficiency and ligament deficiency when dealing with any chondral defect and with the patellofemoral joint tracking should be optimal

Arthroscopic debridement of localised defects (chondroplasty)

The term chondroplasty is used for mechanical or thermal reshaping of uneven articular cartilage. The aim is to debride loose chondral flaps and fibrillated articular cartilage to a smoother surface avoiding any damage to healthy surrounding cartilage.

There are two types of Arthroscopic chondroplasty –

  • Mechanical- performed using mechanical instruments and arthroscopic shavers
  • Thermal- performed using radiofrequency energy

Chondroplasty has good success rate in improving pain and mechanical symptoms. However, the natural history of progression is not clear and the long-term effects of radiofrequency treatment on cartilage remain unknown. Mechanical chondroplasty using a shaver can still leave behind a fine fibrillated surface. Some authors have reported superior results with RF compared to mechanical shaver (Spahn, Turner, Owens).

Thermal chondroplasty produces chondrocyte death in the surrounding cartilage, potentially even up to subchondral bone (Lu, Mitchell, Caffey). Lu reported that Bipolar RF could produce a wider and deeper zone of cell death compared to Monopolar. Lavage fluid at 37 degrees C produces less chondrocyte damage than fluid at 22 C. Caffey showed that for treatment times of 1 and 3 seconds, cell death measurements ranged from 404 to 539 mum and 1034 to 1283 mum, respectively. When probes were kept a 1.0-mm distance above the cartilage, no cell death or cartilage smoothing was noted. Both shavers and RF probes should be used like a paintbrush to minimise any damage.

Although RF can give a smother finish to chondroplasty, there are conflicting reports on the temperature produced and the zone of chondrocyte death. RF is best avoided until we also understand these issues and the long-term effects of thermal damage. Mechanical chondroplasty is safer but operative technique is important to get a satisfactory surface finish.

Arthroscopic debridement for focal chondral lesions is commonly performed but there are very few comparative studies with other cartilage repair techniques.

Hubbard prospectively compared debridement(n=40) and washout alone(n=36) for localised medial femoral condyle lesions at 4.5 years. The washout group performed poorly. 19 of a total of 32 survivors in the debridement group were painfree.

Freddie Fu compared retrospectively arthroscopic debridement and autologous chondrocyte implantation (ACI). Patients in the ACI and debridement groups had similar demographics and chondral lesions. ACI patients had better outcomes in function and pain relief at 3 years but there were far higher reoperations in the ACI group.

The key tips in Chondroplasty are –

  • Using copious washout
  • Use of suction along with application of a non-aggressive shaver blade like a paintbrush
  • Swapping portals with shaver to improve surface finish.

 


Grade 3 chondral changes

 


Post chondroplasty

 

This video shows a chondroplasty –

Spahn G, Kahl E, Mückley T, Hofmann GO, Klinger HM. Arthroscopic knee chondroplasty using a bipolar radiofrequency-based device compared to mechanical shaver: results of a prospective, randomized, controlled study. Knee Surg Sports Traumatol Arthrosc. 2008 Jun;16(6):565-73.

Barber FA, Iwasko NG. Treatment of grade III femoral chondral lesions: mechanical chondroplasty versus monopolar radiofrequency probe. Arthroscopy. 2006 Dec;22(12):1312-7.

Caffey S, McPherson E, Moore B, Hedman T, Vangsness CT Jr (2005) Effects of radiofrequency energy on human articular cartilage: an analysis of 5 systems. Am J Sports Med 33:1035–1039

Owens BD, Stickles BJ, Balikian P, Busconi BD. Prospective analysis of radiofrequency versus mechanical debridement of isolated patellar chondral lesions. Arthroscopy. 2002 Feb;18(2):151-5

Voloshin I, Morse KR, Allred CD, Bissell SA, Maloney MD, DeHaven KE. Arthroscopic evaluation of radiofrequency chondroplasty of the knee. Am J Sports Med. 2007 Oct;35(10):1702-7.

Yan Lu, Ryland B. Edwards, III, Brian J. Cole, and Mark D. Markel. Thermal Chondroplasty with Radiofrequency Energy: An In Vitro Comparison of Bipolar and Monopolar Radiofrequency Devices. Am. J. Sports Med., Jan 2001; 29: 42 – 49.

Mitchell ME, Kidd D, Lotto ML, Lorang DM, Dupree DM, Wright EJ, Lubowitz JH (2006) Determination of factors influencing tissue effect of thermal chondroplasty: an ex vivo investigation. Arthroscopy 22:351–355

Turner AS, Tippett JW, Powers BE, Dewell RD, Mallinckrodt CH. Radiofrequency (electrosurgical) ablation of articular cartilage: a study in sheep. Arthroscopy. 1998;14:585–591

Fu FH, Zurakowski D, Browne JE et al. Autologous chondrocyte implantation versus debridement for treatment of full-thickness chondral defects of the knee: an observational cohort study with 3-year follow-up. Am J Sports Med. 2005 Nov;33(11):1658-66.

Hubbard MJ. Articular debridement versus washout for degeneration of the medial femoral condyle. A five-year study. J Bone Joint Surg Br. 1996 Mar;78(2):217-9.

Marrow Stimulation Techniques

Marrow stimulation techniques include:

  1. Abrasion chondroplasty
  2. Subchondral drilling
  3. Microfracture
  4. Microfracture with adjunct

Abrasion Chondroplasty

This technique involves abrasion of loose chondral edges and the calcific sclerotic base of the chondral defect. It is performed using a shaver, burr or curette. This exposes vascularity providing a tissue bed for blood clot attachment. The risk is loosing the integrity of the subchondral plate. Johnson noticed a 66% failure rate.
Johnson LL. Arthroscopic abrasion arthroplasty. In: McGinty JB (ed). Operative Arthroscopy. New York, NY: Raven Press; 1991:341-360.

Subchondral Drilling

This technique involves drilling through the subchondral plate using a drill or k-wire. It has essentially been replaced by microfracture due to the thermal damage of cells produced by motorised drilling.

Microfracture

Microfracture is a technique performed using awls with suitably angled tips impacted gently so that vertical holes can be made with no thermal damage.

Microfracture with adjuncts

Microfracture has been combined with the use of a periosteal membrane to contain the cells and improve the repair tissue.

AMIC or autologous matrix induced chondrogenesis involves microfracture combined with the use of a chondrogide membrane to provide containment of cells in the defect. Cancellous bone from the tibial plateau mixed with fibrin glue and patient’s serum is mixed and applied as a paste to the defect providing collagen type-II matrix.

Hydrogels are being currently being tested as scaffolds with cell based techniques.
Breinan HA, Martin SD, Hsu HP, Spector M. Healing of canine articular cartilage defects treated with microfracture, a type-II collagen matrix, or cultured autologous chondrocytes.J Orthop Res. 2000 Sep;18(5):781-9.
Vinatier C, Guicheux J, Daculsi G, Layrolle P, Weiss P. Cartilage and bone tissue engineering using hydrogels. Biomed Mater Eng. 2006;16(4 Suppl):S107-13. Review.

Mosaicplasty

This technique involves harvesting multiple small cylinders of normal articular cartilage with underlying bone from a nonweight bearing area of the affected knee and transplanting them in to the prepared defect. This technique is useful for smaller defects and shows consistent survival of hyaline cartilage.

For large lesions and salvage situations especially with bone loss, fresh osteochondral allografting is a useful option.

Autologous Chondrocyte Implantation (ACI)

This is a two-stage biological treatment procedure aiming to produce hyaline-type cartilage repair. Firstly, a biopsy of healthy cartilage is taken from the affected knee and the chondrocytes are cultured in a suitable environment. The second stage is an open procedure when the cells are reimplanted a few weeks later into the defect beneath a periosteal patch or alternative scaffold.

Stem cells can be harvested from a variety of sources and the future may be to achieve one-step biological treatment.

Paste grafting

Minced autologous cartilage
Minced allogenic cartilage

Synthetics

Trufit plug- Smith & Nephew
SaluCartilage- Solumedica
ChondroCushion-Advanced Bio Surfaces,Inc.
Hemicap- Arthrosurface.

Natural History

The natural progression of untreated chondral defects is still unclear. Linden noticed that at an average of 33 years follow-up of Osteochondritis Dissecans lesions in adults, 55% progressed to osteoarthritis whilst children with the same lesion did not progress to osteoarthritis.
Linden B. Osteochondritis dissecans of the femoral condyles: a long-term follow-up study. J Bone Joint Surg Am. 1977 Sep;59(6):769-76.

Shelbourne compared two groups of patients- one with untreated incidental grade 3 or 4 chondral defect at the time of ACL reconstruction and the control group with a normal knee at the time of ACL reconstruction. The patients in the control group had significantly higher subjective scores than did the patients with a defect. At least 79% of the patients in both groups returned to jumping, twisting, and pivoting sports at least at the recreational level.
Shelbourne KD, Jari S, Gray T. Outcome of untreated traumatic articular cartilage defects of the knee: a natural history study. J Bone Joint Surg Am. 2003;85-A Suppl 2:8-16.

Widuchowski retrospectively analysed 25,124 arthroscopies Cartilage lesions were classified in accordance with the Outerbridge classification. Chondral lesions were found in 60% of the patients. Documented cartilage lesions were localized in 67%, osteoarthritis in 29%, osteochondritis dissecans in 2% and other types in 1%. The patellar articular surface (36%) and the medial femoral condyle (34%) were the most frequent localization of the cartilage lesions. Curl noticed that patients under 40 years of age with grade IV lesions accounted for 5% of all arthroscopies.

Lars Engebretsen in a prospective large study on 993 knee arthroscopies noticed articular cartilage pathology in 66% and a localized cartilage defect was found in 20%. A localized full-thickness cartilage lesion (ICRS grade 3 and 4) was observed in 11% of the knees. Of the localized full-thickness lesions, 55% (6% of all knees) had a size above 2 cm(2). Brittberg in another prospective study of 1000 arthroscopies noticed focal chondral defects(ICRS grade 3 and 4) in 19% of patients with average size 2.1cm2 . The medial femoral condyle is the commonest site.
Widuchowski W, Widuchowski J, Trzaska T. Articular cartilage defects: study of 25,124 knee arthroscopies.Knee. 2007 Jun;14(3):177-82.
Epub 2007 Apr 10. Curl WW, Krome J, Gordon ES et al. Cartilage injuries: a review of 31,516 knee arthroscopies.Arthroscopy. 1997 Aug;13(4):456-60.
Arøen A, Engebretsen L et al. Articular cartilage lesions in 993 consecutive knee arthroscopies.Am J Sports Med. 2004 Jan-Feb;32(1):211-5.
Hjelle K, Brittberg M et al. Articular cartilage defects in 1,000 knee arthroscopies. Arthroscopy. 2002 Sep;18(7):730-4.