Autologous chondrocyte implantation (ACI) and mosaicplasty are both claimed to be successful for the repair of defects of the articular cartilage of the knee but there has been no comparative study of the two methods. A total of 100 patients with a mean age of 31.3 years (16 to 49) and with a symptomatic lesion of the articular cartilage in the knee which was suitable for cartilage repair was randomised to undergo either ACI or mosaicplasty; 58 patients had ACI and 42 mosaicplasty. Most lesions were post-traumatic and the mean size of the defect was 4.66 cm. 2. The mean duration of symptoms was 7.2 years and the mean number of previous operations, excluding arthroscopy, was 1.5. The mean follow-up was 19 months (12 to 26). Functional assessment using the modified Cincinatti and Stanmore scores and objective clinical assessment showed that 88% had excellent or good results after ACI compared with 69% after mosaicplasty. Arthroscopy at one year demonstrated excellent or good repairs in 82% after ACI and in 34% after mosaicplasty. All five patellar mosaicplasties failed. Our prospective, randomised, clinical trial has shown significant superiority of ACI over mosaicplasty for the repair of articular defects in the knee. The results for ACI are comparable with those in other studies, but those for mosaicplasty suggest that its continued use is of dubious value

Aim: evaluation of articular cartilage defects repair of the knee by mosaicplasty. Methods: 12 cases of 12 knees (8 males and 4 females) that underwent cartilage repair by mosaicplasty for femoral condyle defects were reviewed. Mean patient age at time of surgery was 34 years old (23 Ð 47 years). All cases were diagnosed by arthroscopy and 3 underwent preoperatively MRI. Postoperatively 5 cases were investigated by MRI, 9 underwent a second-look arthroscopy and in 2 cases we performed a needle biopsy. The average followup period from surgery was 12 months. The mean period from surgery to follow-up arthroscopy was 7 months. Results: Clinical results were appreciated by HSS Score. According to this scale the mean rate of our results was 90. All cases that underwent a second-look arthroscopy showed a good articular surface. Needle biopsy demonstrated regeneration of hyaline cartilage, even if some structural differences occurred. Conclusions: Mosaicplasty seems to be an efþcient alternative for treatment of limited cartilage defects. Needle biopsy demonstrated that regenerated hyaline cartilage in the gaps among mosaicplasty areas has not the same structure and quality like the natural cartilage. Therefore degeneration is possible and long term careful observation is needed

Purpose: To assess costs and health status outcomes following ACI and mosaicplasty used to treat chondral knee defects (1). Methods: Patients received ACI or mosaicplasty at the Royal National Orthopaedic Hospital between 1997 and 2001, or, were on a waiting list for ACI. Resource use per patient was collected to two years post-operatively. A postal questionnaire collected sociodemographic characteristics, knee-related (Modified Cincinnati Knee Rating System) and general health status (EQ-5D). Results: 53 ACI, 20 mosaicplasty and 22 patients waiting for ACI participated in this study. The average cost per patient was higher for ACI (£10,600: 95%CI £10,036-£11,214) than for mosaicplasty (£7,948: 95%CI £6,957-£9,243). Estimated average EQ-5D social tariff improvements for QALYs (quality adjusted life years) were 0.23 for ACI and 0.06 for mosaicplasty. Average costs per QALY were: £23,043 for ACI and £66,233 for mosaicplasty. The ICER (incremental cost effectiveness ratio) for providing ACI over mosaicplasty was £16,349. Post-operatively, ACI and mosaicplasty patients (combined) experienced better health status than patients waiting for ACI. ACI patients tended to have better health status outcomes than mosaicplasty patients, although this was not statistically significant. Conclusions: Average costs were higher for ACI than for mosaicplasty. However, both the estimated cost per QALY and ICER fell beneath an implicit English funding threshold of £30,000 per QALY. To our knowledge this is the first study to compare the costs and utility of ACI with alternative ‘best’ treatments for people with chondral knee problems. Prospective studies are required to confirm these results

Purpose: We report the results of a prospective consecutive series of 25 patient with non-degenerative chondral lesions treated by mosaicplasty osteochondral grafts. Material and method: The main group was composed of 22 knees, including 16 with osteochonritis dissecans, five with cartilage damage concomitant with chronic anterior laxity, and one with necrosis of the medial condyle. The other lesions involved the talus. Mean patient age was 28 years. Mean follow-up was 13 months (range 1 – 39 months). Among the knee group, 15 patients underwent standard mosaicplasty. The lesion measured 1.96 cm2 on the average. For the other cases, associated procedures included: valgus tibial osteotomy (n=4), anterior ligamentoplasty (n=3). There were few complications except one case of infection. Clinical assessment was based on the new ICRS chart (with an updated IKDC subjective score sheet). The subjective IKDC score was 48.7% preoperatively. Results: Mean coverage of the lesion was 68.5%. Solitary mosaicplasty provided good results. The subjective IKDC score was 67.5% and 77% of the patients experienced little or no pain in their knee. Two-thirds of the patients scored their performance at 8 or more on the 10 point scale. The objective IKDC score gave 11/15 A and 4/15 B. There was one complication related to the donor site causing femoropatellar impingement after harvesting substantial graft material. Recovery was more difficult for patients with associated procedures and results were less satisfactory. All patients underwent an MRI at six months that showed in general a good morphological aspect. Discussion: The technique used is particularly important due to a number of pitfalls and difficulties requiring much surgical skill. While we have found that most associated procedures such as grafting the anterior cruciate ligament are warranted, the appropriateness of an associated osteotomy would be highly debatable. Lesions measuring more than 3 cm2 correspond to the limit of this technique. Conclusion: Mosaicplasty is a reliable method for cartilage repair. Long-term assessment will allow better indications and identification of any iatrogenic factors in order to determine the appropriate place for this technique among the other methods used for cartilage repair

The past ten years have brought plenty of research and technical innovations and also preliminary clinical success in cartilage repair. The common target of all methods utilised is to produce a sufficiently stable quality of cartilage repair or regenerate. However, yet today clinical, radiological and histological results analysing the different techniques are somewhat contradictory. The different lines of clinically applied and basic research have focused on:. 1) Spontaneous natural filling of the defect with fibro-cartilage of variable solidity. - Abrasion chondroplasty, drilling or microfracturing to allow for mobilisation of progenitor cells and mesenchymal stem cells from the cancellous bone into the defect and develop to a hyaline like cartilage. - Stem cell treatment (in vivo or ex vivo theory of potential technique by which stem cells could be brought to a defect to create cartilage; so far no directly linked product available). 2) Transplantation of osteochondral auto grafts (Mosaicplasty, OATS, SDS, patellar graft) or allograft. 3a) Autologous chondrocyte transplantation and periosteal coverage (ACT) to cover bigger surfaces. 3b) Implantation of second and third generation ex vivo products and create less morbidity but without knowing whether the results are as long-lasting as for the originally described technique (chondrocytes cultured on membranes, MACI, in gels, implantation of a stable three-dimensional de novo cartilage disk or even engineered osteochondral grafts, AMIC: autologous membrane induced chondrogenesis). A fair amount of today’s laboratory research is focusing on the culture of the patients own chondrocytes or his own stem cells. Clinically, some methods can be applied in all indications regardless of size, localisation, depth of the lesion up to the age of fifty years and this is valid for lesions in the knee, the shoulder, the talus, the elbow etc. Other methods like AOCT should not be used for lesions over 2cm in diameter because of donor side morbidity. All methods claim to have an 85% outcome success rate. Regarding the histological content of the successful implants or the reformed cartilage, microfracturing produces a cartilage implant containing a fibrocartilage that looks similar to the hyaline like cartilage of ACI at two years. Mosaicplasty plugs provided great care is applied during insertion avoiding damage of the cylinders and cartilage death-a special instrumentation has been developed with ZIMMER, the Soft Delivery System, SDS to avoid force during impaction. They remain hyaline provided they are inserted without being prone or deep sunken and the surface convexity of the femoral condyle is restored and provided they are inserted tightly next to each other. There is agreement that this is more difficult in arthroscopic techniques. One agrees also that results are dependent on the alignment of the limb. If the compartment treated is overloaded, there is less chance for integration. Osteotomy has therefore a solid position in the armamentarium of the cartilage surgeon- up to 50% of our cases get an osteotomy as part of their treatment regardless of which technique is utilised. As complications in autologous osteochondral grafting we may observe destruction of the hyaline cartilage cap, non integration and pseudarthrosis or fractures of the cylinders (of special risk are smokers), especially when grafts are not inserted tightly to each other and there is lack of stability with fluid leakage out of the cartilage caps. Rarely ossification of the cartilage is observed when a thin capped cylinder retrieved in the peripheral zone of the femoral trochlea is implanted in an area of thick cartilage as in the centre of the patella where the cartilage is 5 mm thick. Donor site pathology in mosaicplasty is an issue of concern mainly if more than six plugs are removed from the femoropatellar joint. This alone can create clinical symptoms. Nicotine abuse, probably for all techniques decreases the rate of success of cartilage repair or regeneration and osteotomy healing. Roughly 300 cases have been treated during the last 10 years. The results were reported in 2002. As an alternate single surgery technique to microfracturing and mosaicplasty we adopted the “Autologous membrane induced chondrogenesis” (AMIC) technique proposed by Behrens that we find especially useful in OCD. In this relatively young technique we curette the defect and apply microfractures to the basis of the osseous defect. Then we gain cancellous bone from the tibial plateau and mix it with fibrin glue, of which 50% of the thrombin portion is replaced by the serum of the patient as a source of growth factor. This paste of bone and enriched fibrin glue is filled in the defect which is then covered by the porcine Chondrogide membrane (Geistlich) that is glued on and which we can as well suture to the defect. The AMIC technique in combination with microfractures can be utilised for the coverage of pure cartilage defects alone where the membrane is glued alone or fixed on the defect in combination with 5-0 resorbable sutures. In the first two weeks following surgery, after treatment is very defensive to avoid loss of the membrane. After two months of crutch walking with 15 kg of weight we observe a nice osseous integration of the graft and a covering layer that looks promising. After 4–6 months activity can be increased depending on the size of the defect. This is a young technique that we adopted in mid 2003 with 30 cases treated so far, therefore strict observation is required over the upcoming years regarding clinical results and durability and also the composition of this neocartilage. So far it seems to be an interesting alternative to Mosaicplasty since it combines principles of cell therapy with an artificial and instant biological containment that acts against the loss of cells thus acting as a internal bioreactor with the patients own growth factor support

Many methods have been described over the past 5 years for repair of articular cartilage defects. The best reported results have been from the use of autologous chondrocyte transplantation (ACT)(1) and mosaicplasty.(2) There have, however, been no prospective clinical trials of these two methods. In this trial 70 patients were prospectively randomized to receive either autologous chondrocyte transplantation (37) or mosaicplasty (33) in the knee. 37 patients were female and 33 male. The average age was 32 years (16 – 44). The indications for surgery were persistent pain and mechanical symptoms in the knee with an isolated defect of the articular cartilage. 38 (56%) were post-traumatic, 12 (16%) due to osteochondritis dissecans, 10 (14%) due to previous meniscectomy, and 10 (14%) due to chondromalacia patellae. The size of the defects ranged from 2cm2 to 12cm2 (mean 4.8cm2). There were 35 defects on the medial femoral condyle, 13 on the lateral femoral condyle, 17 on the patella and 5 on the trochlear. 31 patients were undergoing primary surgery and 39 secondary surgery. All were independently reviewed using the Visual Analogue Pain Score, the Cincinatti Pain Score and the Stanmore Score. Patients were arthroscoped at one year with MRI scan and biopsies where possible. Results: The visual analogue pain score improved overall from a mean of 5.4 (range 3.4 – 7.4) pre-operatively to 3.9 (1.8 – 5.1) at one year review. Similarly the Cincinatti pain score improved from 6.5 pre-operatively to 10.2 post-operatively and the Cincinatti function score improved from 46 to 62 at one year before sport commenced. Overall 71% (49) patients were excellent or good on the clinical scoring scales, 15% (11) were fair, and 14% (10) were poor. The 10 poor results were no different from the main group with regard to age, sex, pain level or site or size of lesion. However, 5 were secondary procedures, 2 had multiple lesions, and 3 had had previous ruptured anterior cruciate ligaments. Arthroscopy and biopsy of 21 lesions so far after one year has shown mature articular cartilage in 2, and immature cartilage in 19. In all cases there was bonding of the repair tissue to the underlying bone. This study is already clarifying the role of ACT and mosaicplasty in the management of cartilage defects in the knee and also the necessity for the use of periosteal covering membrane

Autologous chondrocyte implantation (ACI) and mosaicplasty are methods of treating symptomatic articular cartilage defects in the knee. This study represents the first long-term randomised comparison of the two techniques in 100 patients at a minimum follow-up of ten years. The mean age of the patients at the time of surgery was 31.3 years (16 to 49); the mean duration of symptoms pre-operatively was 7.2 years (9 months to 20 years). The lesions were large with the mean size for the ACI group being 440.9 mm. 2 . (100 to 1050) and the mosaicplasty group being 399.6 mm. 2. (100 to 2000). Patients had a mean of 1.5 previous operations (0 to 4) to the articular cartilage defect. Patients were assessed using the modified Cincinnati knee score and the Stanmore-Bentley Functional Rating system. The number of patients whose repair had failed at ten years was ten of 58 (17%) in the ACI group and 23 of 42 (55%) in the mosaicplasty group (p < 0.001). The functional outcome of those patients with a surviving graft was significantly better in patients who underwent ACI compared with mosaicplasty (p = 0.02)

Introduction: Osteochondral mosaicplasty is gaining popularity as a treatment for isolated chondral defects in femoral condyles. Most systems use a metal punch to impact the osteochondral grafts in pre-drilled defects. Damage to the chondrocytes during impaction grafting is of concern and new methods are being sort to minimise this deleterious effect. This study was designed to see if using a plastic punch instead of a metal punch reduces the extent of chondrocyte damage in osteochondral mosaic plasty. Method: Ten fresh sheep knees were used to harvest 30 osteochondral plugs using the COR system. The opposite condyles were then prepared to receive the osteochondral grafts. Ten plugs were impacted using a metal punch and ten using a plastic punch. The ten remaining plugs were used as controls. The plugs were then recovered and incubated for 24 hours before being stained with MTT. The stained cartilage was then photographed using a digital macroscope. The images were interpreted using a graphics analysis programme. Results: There was no significant difference in the extent of chondrocyte damage between the two groups. However the extent of chondrocyte damage in the impacted groups was significantly greater than the control group. Conclusions: Impaction grafting clearly damaged the chondrocytes of the osteochondral plug. In our study using a plastic punch did not reduce the extent of chondrocyte damage during mosaicplasty

Introduction: Adequate congruency and primary stability are vital for good long-term results after mosaicplasty. The strength of press-fit stability of the grafts depends upon the length and diameter of the graft, extent of dilation and bone quality. The aim of our study was to quantify the effect of graft diameter and dilation length on the primary stability of single osteochondral grafts against compression and compare the stability of single and multiple osteochondral grafts in an in vitro biomechanical animal model. Methods: In the single graft series one osteochondral graft was transplanted from the trochlea of porcine femurs to the weight-bearing area of the lateral femoral condyle, while in the multiple graft series three grafts were transplanted in a row or in circular fashion in the same position. We used the MosaicPlasty instruments (Acufex, Smith & Nephew Inc. MA, USA). The specimen was installed on a testing machine (Computer controlled ZWICK FR005TH type tensile machine, Zwick GmbH Ulm, Germany) and the graft was first pushed in level with the surrounding cartilage surface, then it was pushed 3 mm deeper. The push-in forces were measured and the compression curve was registered. Results: In the case of single 4.5-mm grafts, the mean level push-in force was 43.5 N, pushing 3 mm deeper needed a mean of 92.5 N (n=13). In the case of single 6.5-mm grafts, level push-in needed a mean of 76.2 N, while for pushing 3 mm deeper a mean of 122.2 N force had to be used (n=14). The length of the drill-hole and the dilation were both 20 mm in each setting. When using 20 mm long drill-holes and 15 mm dilation length, the values above were found to be 36.6 N and 122.5 N in the case of 4.5-mm grafts (n=12). In case of multiple grafting level push-in needed a mean force of 31.8 N in the row series, while pushing 3 mm deeper needed a mean of 52.17 N (n=7). In the circle series level push-in needed a mean of 30.44 N, while for pushing 3 mm deeper a mean of 54.33 N force had to be used (n=9). Conclusions: These results suggest that grafts of greater diameter are more stable in absolute values and the stability may be increased by shorter dilation length, while level push-in forces do not increase significantly. Multiple grafts may not be as stable as single grafts after transplantation and transplantation in a row or in circular fashion does not influence stability

Mosaicplasty. 1. and Autologous Chondrocyte Implantation. 2. (ACI) are both modern cartilage repair techniques used to repair symptomatic articular cartilage defects in the knee, based on small osteochondral grafts and cultured chondrocytes respectively. The aim is the restoration of articular cartilage, but until now there is no data comparing the two methods. 100 consecutive patients aged 15–45 with a symptomatic articular cartilage lesion in the knee suitable for cartilage repair were randomised at arthroscopic assessment to undergo either mosaicplasty or ACI. 42 patients underwent mosaicplasty, 58 had ACI. Mean age at time of surgery was 31 years and the average defect size 4. 66 cm. 2. . 46% of the defects were post-traumatic, 19% had osteochondritis dissecans, 14% had chondromalacia patella and 16% had lesions of unknown aetiology. 53% had a medial femoral condyle lesion, 25% patella, 18% lateral femoral condyle, 3% trochlea and there was one defect of the lateral tibial plateau. The mean duration of symptoms was 7. 2 years and the average number of previous operations (excluding arthroscopies) was 1. 5. Only 6 patients had no prior surgical interventions to the affected knee. The mean follow-up was 1. 7 years. Patients were evaluated using Modified Cincinnati and Stanmore Functional rating systems, visual analogue scores and clinical assessment. Arthroscopy and biopsy was performed at one year and repair assessed with the International Cartilage Repair Society grading system. Clinical results at one year showed 70% of mosaic-plasty patients and 87% of ACI patients had a good or excellent result. Arthroscopy at one year demonstrated more complete healing in ACI patients. Eleven (26%) of the mosaicplasty group subsequently failed clinically and arthroscopically, with peak failure at 2 years. At one year follow-up, both techniques of articular cartilage repair can be useful in selected patients. ACI is preferred for lesions of the patella. Long-term follow-up is needed to assess the durability of articular cartilage repair using these methods, in particular mosaicplasty which showed signs of progressive failure over 2 years

Background. Autologous chondrocyte implantation (ACI) and mosaicplasty (MP) are two methods of repair of symptomatic articular cartilage defects in the adult knee. This study represents the only long-term comparative clinical trial of the two methods. Methods. A prospective, randomised comparison of the two modalities involving 100 patients with symptomatic articular cartilage lesions was undertaken. Patients were followed for ten years. Pain and function were assessed using the modified Cincinnati score, Bentley Stanmore Functional rating system and visual analogue scores. ‘Failure’ was determined by pain, a poor outcome score and arthroscopic evidence of graft disintegration. Results. Patients had a mean age at index operation of 31. There was a long mean pre-op duration of symptoms of seven years and the defects had an average of 1.5 operations (excluding arthroscopy) to the articular cartilage lesion prior to the cartilage repair surgery. The aetiology of the articular cartilage defects was mainly trauma; some patients had osteochondritis dissecans or chondromalacia patellae. Five patients were lost to follow-up. A total of 23 out of 42 mosaicplasty patients failed, 10 out of 58 ACI patients failed (p<0.001). Most patients did well for the first two years when there was a steep failure of mosaicplasty patients, after which the failure rate was more constant. There was a low steady failure rate of ACI over the 10 years. Older patients treated by ACI did worse than younger patients; age was less of a prognostic indicator in MP. Patients irrespective of gender or aetiology of the defect fared better with ACI than MP. Conclusion. At ten years, patients who underwent cartilage repair using ACI fared significantly better than those who underwent mosaicplasty

Aims: To evaluate clinical and radiological results and to present variant of possible mosaicplasty application for treatment of large osteochondral defects. Methods: Between 1998 and 2001, seven patients were operated on with a large osteochondral defect of the femoral condyle using the cylindrical grafts. The age of the þve male and two female ranged from 19 to 27 years. Initially all of them suffered from an osteochondrosis dissecans which was located at the typical site on the medial condyle of the femur. A cylindrical graft is taken from the medial rim of the femoral trochlea, away from femoropatellar weight-bearing areas, with a cylindrical cutter of the 6–11 mm diameter. The hole of recipient site is prepared with a same cutter less by 1 mm diameter. A next graft is inserted in the same way and can cross from preceding graft. The procedure is repeated 2–3 times. The grafts should cover at least 90% of the cartilage defect. Results: The follow-up study was from 1 to 3 years and showed an improvement from 37 points preoperatively to 87 points postoperatively (Cincinnati knee score). All patients returned to there previous professions as well as mild sports activity. Conclusions: For the operative treatment of large chondral defects at the femoral condyle autologous osteochondral transplantation using the cylindrical grafts with mosaicplasty seems to be a successful alternative

Introduction and purpose: To assess the results of the reconstruction of osteochondral lesions and transchondral fractures of the talus by means of mosaicoplasty.

Materials and methods: 20 patients (mean age: 30) were operated on in 3.5 years, with a minimal follow-up of 6 months. There were 17 medial and 3 lateral lesions. Ferkel’s and Sgaglioni’s classifications were used for the CT images. Medial lesions were approached by means of an osteotomy of the tibial malleolus. Lateral lesions were treated either directly or through an osteotomy of the fibular malleolus. Chondral lesions were debrided; the cylindrical osteochondral grafts were harvested from either the upper part of the femoral condyle or the anterior part of the talus. They were subsequently inserted into the talar dome. An average of three grafts were used (range: 1–7 tesseras). Patients non-weight bearing for 2–4 weeks. Movement was allowed after 7 days postop.

Results: Results were assessed by means of the Hannover and the Bandi scores. With the former, 94% of cases had excellent or good results; with the latter 94.7 % results were good with no knee morbility or talar complications. Complications: one case had a superficial infection.

Conclusions: In a mosaicoplasty there is either a replacement of the damaged bone or a filling of defect in the cartilage. The rehabilitation time is short and no painful sequela remain in the donor joint.

Aims: In recent years more and more studies tried to evaluate possible inßuences of different growth factors on hyaline cartilage regeneration. In a rabbit model, HGF (hepatocyte growth factor) was proven to increase the amount of hyaline-like chondrocytes in a mixed þbrocartilaginous regenerate of small defects. The present study was undertaken to evaluate, whether intraarticular administration of hepatocyte growth factor inßuences the ingrowth of osteochondral grafts in a sheep model. Methods: Both knee joints of a sheep were opened surgically and osteochondral grafts were harvested and simultaneously transplanted to the contralateral compartment. The sheeps were divided into two groups. In one group hepatocyte growth factor was administered by intraarticular injections given three times a week for four weeks. The control group received isotonic sodium chloride injections. The animals were sacriþced after three months and the received knee joints were evaluated histologically. Results: Histological evaluation showed that the autologous osteochondral grafts were healed in at the level of the subchondral bone. A healing or ingrowth at the level of the cartilage could not be observed. Anyway, histological evaluation of the transplanted grafts according to Mankin showed, that the cartilage of the HGF group showed less signs of degeneration than the control group. In the HGF group less cloning of chondrocytes and less irregularities of the articular surface were observed. Conclusion: In conclusion, HGF positively inßuenced the structure of the transplanted osteochondral graft, but could not diminish the þssures in the marginal zone of the grafts.

Introduction: Osteochondral mosaic plasty is gaining popularity as a treatment for isolated chondral defects in femoral condyles. Most systems use a metal punch to impact the osteochondral grafts in pre-drilled defects. Damage to the chondrocytes during impaction grafting is of concern and new methods are being sort to minimise this deleterious effect.

This study was designed to see if using a plastic punch instead of a metal punch reduces the extent of chondrocyte damage in osteochondral mosaic plasty.

Method: Ten fresh sheep knees were used to harvest thirty osteochondral plugs using the COR system. The opposite condyles were then prepared to receive the osteochondral grafts. Ten plugs were impacted using a metal punch and ten using a plastic punch. The ten remaining plugs were used as controls. The plugs were then recovered and incubated for 24 hours prior to being stained with MTT. The stained cartilage was then photographed using a digital macroscope.

Images were interpreted using a graphics analysis programme.

Results: There was no significant difference in the extent of chondrocyte damage between the two groups. However, the extent of chondrocyte damage in the impacted groups was significantly greater than the control group.

Conclusion: Impaction grafting clearly damages chondrocytes of the osteochondral plug. In our study using a plastic punch did not reduce the extent of chondrocyte damage during mosaic plasty.

Surgical reconstruction of articular surfaces by transplantation of osteochondral autografts has shown considerable promise in the treatment of focal articular lesions. During mosaicplasty, each cylindrical osteochondral graft is centred over the recipient hole and delivered by impacting the articular surface. Impact loading of articular cartilage has been associated with structural damage, loss of the viability of chondrocytes and subsequent degeneration of the articular cartilage. We have examined the relationship between single-impact loading and chondrocyte death for the specific confined-compression boundary conditions of mosaicplasty and the effect of repetitive impact loading which occurs during implantation of the graft on the resulting viability of the chondrocytes. Fresh bovine and porcine femoral condyles were used in this experiment. The percentage of chondrocyte death was found to vary logarithmically with single-impact energy and was predicted more strongly by the mean force of the impact rather than by the number of impacts required during placement of the graft. The significance of these results in regard to the surgical technique and design features of instruments for osteochondral transplantation is discussed

Autologous osteochondral cylinder transfer is a treatment option for small articular defects, especially those arising from trauma or osteochondritis dissecans. There are concerns about graft integration and the nature of tissue forming the cartilage-cartilage bridge. Chondrocyte viability at graft and recipient edges is thought to be an important determinant of quality of repair. The aim was to evaluate cell viability at the graft edge from ex vivo human femoral condyles, after harvest using conventional technique. With ethical approval and patient consent, fresh human tissue was obtained at total knee arthroplasty. Osteochondral plugs were harvested using the commercially available Acufex 4.5mm diameter mosaicplasty osteotome from regions of the lateral femoral condyle (anterior cut) that were macroscopically non-degenerate and microscopically non-fibrillated. Plugs were assessed for chondrocyte viability at the graft edge using confocal laser scanning microscopy (CLSM), fluorescent indicators and image analysis. The central portions of the plugs remained healthy, with > 99% cell viability (n=5). However, there was substantial marginal cell death, of thickness 382 ± 68.2 microm in the superficial zone (SZ). Demi-plugs were created by splitting the mosaicplasty explants with a fresh No. 11 scalpel blade. The margin of SZ cell death was 390.3 ± 18.8 microm at the curved edge of the Acufex, significantly (Mann-Whitney; P= 0.0286; n =4) greater than that at the scalpel cut (34.8 ± 3.2 microm). Findings were similar when the cartilage was breached but the bone left intact. In time-course experiments, the SZ marginal zone of cell death after Acufex harvest showed no increase over the time period 15 minutes to 2 hours. Mathematical modelling of the mosaicplasty surface shows that cell death of this magnitude results in a disturbing 33% of the superficial graft area being non-viable. In conclusion, mosaicplasty, though capable of transposing viable hyaline cartilage, is associated with an extensive margin of cell death that is likely to compromise lateral integration. There would appear to be considerable scope for improvement of osteochondral transplant techniques which may improve graft-recipient healing and clinical outcomes

The June 2012 Knee Roundup. 360. looks at: ACI and mosaicplasty; ACI after microfracture; exercise therapy and the degenerate medial meniscal tear; intra-articular bupivacaine or ropivacaine at knee arthroscopy; lateral trochlear inclination and patellofemoral osteoarthritis; bone loss and ACL reconstruction; assessing stability using the contralateral knee; tranexamic acid and a useful review of knee replacement

Aims: To compare mosaicplasty with microfractures in the knee joint osteochondral defects treatment. Methods: Between 1998 and 2001 twenty-three patients underwent mosaicplasty and 23 patients (controls) microfracture procedures for the knee joint osteochondral or chondral pathology treatment. Patients were selected and evaluated randomly through ICRS and modiþed HSS scales, arthroscopicaly, histologically, rent-genologicaly and with MRI. Average follow-up was 12,4(range 10–14 months) and 23,6 months (range 22 –25 months). Results: The defect-size in these patients ranged between 12 mm. 2. and 23 mm. 2. in diameter and had an average-size of 15 mm. 2. 22(95,6%)mosaicplasty results were excellent and good at the time of last follow-up. 16(69,5%) in the control group results were excellent and good and 7(30,4%) Ð fair 23,6 months post operations. Modiþed ICRS and HSS evaluations showed statistically signiþcantly better results in the mosaic-plasty group at the 12,4 and 23,6 months (p< 0.005; p< 0.0001) post operations. Last follow-up showed deterioration in microfracture group (p< 0,02). Conclusions: Mosaicplasty can be recommended for the treatment of osteochondral defects in the weight-bearing area of the knee as a safe procedure for transplantation of hyaline cartilage