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Early Results With Osteochondral Autogenous Cartilage Transfer For Osteochondral Defects In The Knee Joint

*S Rajkumar, R Pande, PJ Livesley

*King’s Mill Hospital, Sutton-in-Ashfield NG17 4JL,UK.

Address for Correspondence
S Rajkumar
King’s Mill Hospital,
Sutton-in-Ashfield NG17 4JL, UK.


We report our experience with osteochondral autogenous cartilage transfer for osteochondral defects in the knee joint in five patients. They were followed up for over a year. Suitability for this procedure was assessed by arthroscopy and knees with focal cartilage defect of 1.5cms or less were selected. Associated intra-articular pathology if any was recorded and treatable lesions like meniscal tears and lateral retinacular tightness were attended to at the same time. The osteochondral autologous transplantation (O.A.T.S) procedure was performed as an open procedure at a second sitting. 
The patients were mobilized non-weight bearing with crutches for six weeks post-operatively allowing flexion up to 90 degrees and quadriceps exercises. An independent observer performed the evaluation before and after the procedure using the modified knee scoring system of the Hospital for Special Surgery. The pre and post-op scores were compared. As the knee function in terms of range of movements, stability and alignment was good pre-operatively, most patients did not show striking improvements in these modalities. 
Severe pain scoring zero on the pain scale improved to ‘mild or occasional’ scoring 45/50 in three patients. One patient reported marginal and one, no improvement in pain. The walking distance improved considerably; unlimited walking distance in three patients (scoring 50/50) and one patient graduated to walking five to ten blocks (scoring 30/50). One patient reported no change.
Two patients who scored zero with inability to do stairs had progressed to ‘normal up & down’ (scoring 50/50) and, ‘normal up, down with rails’ (scoring 30/50) respectively. Two patients who could climb up and down with rails (scoring 30/50) pre-operatively reported to do so un-aided (scoring 50/50) after surgery. There were few minor complications in the way of swelling (2), haemarthrosis (1) and pain (1), which settled down quickly. 
Key words: Osteochondral defect, knee joint, cartilage transfer

J.Orthopaedics 2006;3(3)e9


Articular cartilage defects are not uncommon and has been reported widely in literature. These defects have a poor capacity to heal. They are the forerunners of further degeneration and osteoarthritis in the joint. There has been no effective treatment option until recently. Effective treatment of these defects could lead to postponement of knee degeneration and delay extensive procedures like knee replacement to a significant degree. The treatment options are debridement and drilling( 1),micro fracture, cartilage transfer(cadaveric/ allograft/autograft) and transfer of cultured cartilage cells into defects. There is advantages and disadvantages with each technique. 

Debridement of defects leads to healing with fibro cartilage, which is liable to fail to compressive forces in the long term. Cadaveric allograft transfer and cultured cartilage transfer are technically complicated and require laboratory facilities. The Osteochondral autologous cartilage transfer system (O.A.T.S) technique offers a dual advantage of transferring true hyaline cartilage to the defect on a bone base and being technically simpler and more feasible with the average orthopaedic practice. Here we report our early experience of such procedure.

Method and materials  

This prospective case series study was undertaken at King’s Mill Hospital between August 1999 and June 2001.The patients selected for this study were among those who presented with complaints of knee pain and difficulty mobilizing at the out-patients clinic. 

Inclusion criteria:

Those who had a full thickness medial femoral condylar cartilage defect of 1.5cms or less at arthroscopy were deemed suitable for this procedure. Multiplicity of defects was not considered a contraindication as long as the defects were focal in nature. 

Exclusion criteria:

Larger defects greater than 1.5cms in diameter and bilateral knee defects were excluded from the study. 

The defects were present in the central weight bearing area of the femoral condyle.Potential donor sites were identified and recorded at the initial arthroscopy. Accompanying intra-articular pathology if any was recorded and treatable lesions like meniscal tears and lateral retinacular tightness were dealt with at the same time. 

O.A.T.S. Procedure:

The patient was explained about this procedure in detail at the clinic visit with an information sheet explaining the complications of this procedure. The modified knee scores of the Hospital for Special Surgery was assessed during this visit. On the day of the operation, the procedure details was explained and an informed written consent was obtained. The patient demographics and indications for the surgery was entered on to a preformed sheet.

The transfer was performed as an open procedure by the senior author(PJL) under general anaesthesia with tourniquet control. The knee was opened by a standard anterior midline incision with medial para-patellar approach with eversion of patella. 

 The dimensions of the defect was confirmed and graft harvested from the donor site which was usually the outer edge of the lateral femoral condyle using ‘Protec’ tubular osteochondral harvesters specially designed for this purpose. The recipient area was curetted out and cancellous bone harvested. The donor graft was inserted into the defect and impacted firmly. The cancellous bone harvested from the recipient area was then inserted into the donor defect and impacted. 

The knee was closed with a drain in the knee joint and dressing applied.

Post-operatively, all the patients were kept non-weight bearing for six weeks . Physiotherapy was started the next day ;initially continuous passive motion followed by active knee mobilization and quadriceps exercises added after the post-operative pain and swelling subsided. Patients were discharged from hospital on the second or third post-operative day and followed up in clinic. 


All the patients in this case series were evaluated by an independent observer and rated using the modified knee scoring system from the Hospital for Special Surgery(   ).This system is subjective as well as objective and evaluates the knee not only in terms of movements and instability but also its function in terms of pain and ability to walk or climb stairs. Post-operative scores were matched against pre-operative scores an attempt made to objectively assess recovery in individual patients.


This case series included five patients who underwent the O.A.T.S procedure by the senior author.Incidently all five patients were male. The mean age was 36 years (range 28 – 45 years) and all were unilateral (3 right side defect and 2 left side). 

Two patients had a history of road traffic accidents involving the knees of which one had an undisplaced fracture of the patella, which healed well with conservative treatment. Two patients had a history of twisting injury during sports of which one had a ruptured anterior cruciate ligament. One patient had no preceding history of trauma but was grossly overweight. 

Most patients( 4/5) presented with pain in the knee and restriction of activities as the predominant compliant. They had remarkably good range of knee movements( 0 – 120 degrees of flexion) except for one patient who had flexion restricted to 90 degrees. All the knees were stable except for the knee with cruciate ligament rupture. on had flexion contracture or extensor lag and all the knees were well aligned. 

The pre-operative knee scores were good in terms of range of movements, stability and alignment, but the functional scores were very low and all patients revealed gross restriction in ability to walk and climb or descend the stairs. 

Only one patient had an anterior cruciate ligament rupture in our series. This was reconstructed with a bone-patella-tendon autograft done at the same time as the O.A.T.S procedure. One patient had a bucket handle tear of the lateral meniscus, which was resected at arthroscopy while one had a tear of the posterior horn of medial meniscus, which was trimmed. Three patients were noted to have grade two arthritic changes in the patella. 

Knee scores

As the knee function in terms of range of movements, stability and alignment was good pre-operatively, most patients did not show striking improvement in these modalities post-operatively. None of the knees had decreased range of movements, instability or mal-alignment post-operatively. 

Pain: There was a vast improvement in the pain scores. Three patients who reported severe pain scoring zero on the pain scale pre-operatively improved to ‘mild or occasional pain’ scoring 45/50.One patient reported marginal and one, no improvement in pain. 

Stairs: Two patients who were unable to climb or descend stairs and had scores of zero progressed to,’ normal up & down’(50/50) and ,’normal up, down with rails’(30/50)respectively. Two patients who could climb up and down with rails(30/50) pre-operatively reported their ability to do so un-aided(50/50) after surgery. One patient had little improvement in stair climbing and graduated from ‘up with rails, no down’(15/50) to,’ up and down with rails’(30/50). 

Walking distance: Of the three who were walking five to ten blocks pre-operatively scoring 30/50, two could walk unlimited(50/50) while one reported no change in his pre-operative status. Of the two patients who could not walk more than five blocks scoring 20/50 pre-operatively, one could walk an unlimited distance scoring 50/50 while the other graduated to walking five to ten blocks scoring 30/50. 

There were no major complications in our series. Two patients had joint swelling after exertion, which has settled down. One patient reported with haemarthrosis at one month post-op, which was aspirated and settled down without recurrence. Post-operative pain settled down in three weeks.

Discussion :

The treatment of articular cartilage defects in the knee has been a much-debated topic in the last few years. It has been theorized that the filling out of these defects with physiologically efficient tissue will postpone widespread degeneration. This may help delay joint replacement procedures. 

Brittberg et al have demonstrated autologous transfer of chondrocytes from an uninvolved portion of the knee into the defect to be effective in forming viable hyaline cartilage. Wakitani et al went a step ahead and transferred cultured primary mesenchymal cells into the defect in rabbits. The transferred cells were demonstrated to differentiate into cartilage and bone. 

Allograft cartilage transfer from cadavers has also been demonstrated to be effective and the results have been encouraging in the short term. Bobic has demonstrated core grafting in ACL deficient knees and reported good results with a two year follow-up. This technique has the advantage of being the most feasible and technically simple of all the above procedures.  

Our operative procedure was  similar to the one described by Bobic. It varied from Bobic’s procedure in that it was an open procedure and the patients were kept non-weight bearing for six weeks post-operatively. Although Bobic describes the medial condylar defect as a common finding in ACL deficient knees, only one of our five patients was found to be ACL deficient. We also found the defect to co-exist with medial and lateral meniscal tears. 

The most important post-operative finding in our study was the dramatic drop in pain levels. Walking distance and climbing stairs improved considerably. The one patient who did not improve his walking distance, climbing stairs and pain relief was grossly over-weight and has symptoms for eight years prior to this surgery indicating perhaps an improper choice of candidate rather than failure of technique. The absence of any major complications indicate that this is fairly safe procedure for selective defects under normal circumstances.


Our study confirms the results of this procedure to be reasonably good in the short term for selective defects. Further follow-up is required to understand the duration by which the  transplanted cartilage can effectively postpone further degeneration of the joint. The fate of the transferred cartilage in the long term also requires close follow-up.

Bobic recommended a second look arthroscopy and/or MRI scanning as means of further follow-up to assess the cartilage integration and this should be considered. Careful patient selection is necessary for the success of this procedure.

Reference :

  1. Beiser I.H, Kanat I.O    Subchondral bone drilling – a treatment for cartilage defects.    J of Foot and Ankle surgery 1990,29:595-601.
  2. Bobic V    Arthroscopic osteochondral autograft transplantation in ACL reconstruction: a    preliminary clinical study.    Arthroscopy, 1996. 3(4): 262-264.
  3. Bobic V    The current concepts of treatment of articular cartilage defects in the knee:     osteochondral autograft transplantation(O.A.T.S)     Orthopaedic Product News,1999, Mar/April 39-42.
  4. Brittberg M,Linmdahl A, Nilsson A, Ohlsson C, Isaksson O    Treatment of deep cartilage defects in the knee with autologous chondrocyte    Transplantation.    New England journal of medicine, Oct 1994,331(14);889-895.
  5. Chu C, Convery R, Akeson W, Meyers M, Amiel D.    Articular cartilage transplantation: clinical results in the knee.    Clin Orth & Rel Research ,March 1999 ;360:159-181.
  6. Insall J, Dorr L, Scot R, Scott W.    Rationale of the knee society clinical rating system.    Clin Orth & Rel Research, Nov 1989;248:13-14.
  7. Wakitani S, Goto T, Pineda S, Young R, Mansour J, Caplan A, Goldberg V.    Mesenchymal cell based repair of large full thickness defects of articular     Cartilage. JBJS (A), April 1994;76(4): 579-592.


This is a peer reviewed paper 

Please cite as : S Rajkumar: Early Results With Osteochondral Autogenous Cartilage Transfer For Osteochondral Defects In The Knee Joint

J.Orthopaedics 2006;3(3)e9





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