Microfracture Treatment Research Articles

Clinical outcomes after microfracture treatment of full-thikness articular cartilage lesions of the knee

Purpose: The purpose of the study is to evaluate the clinical results after microfracture treatment of the full-thikness articular lesions of the knee. Methods: This study presented clinical outcomes of 51 patients with focal full thikness articular cartilage lesion who were treated with microfracture technique and evaluated according Lysholm-Tegner, Oxford, Womac and KSS scores. According the age we examined of patients younger than 35 years and second group between 36-60 years old. Results: On the basis of follow-up at minimum 18 months, mean improvements in Lysholm-Ttegner scores in younger group (from 38.4-94.1) in older group (from 37.1-87.3), Oxford scores in younger (from 29.5-45.2) and older group (from 25.5-50.5), and Womac score in younger group (from 51.1-94.8) in older (from 50.8-87.8). There was a strong and significant correlation between functional results and age of the patients with full-thikness cartilage lesion less than 2 cm in dijametar. Conclusions: According to our short term results, microfracture technique is effective treatment for the full-thikness cartilage lesions with regard to the improvements of daily activities with a favorable impact on pain relief and better functional results. There was a strong correlation between functional results and age, size of defect location of defect as prognostic parameters.

Ten-Year Follow-up of a Prospective, Randomized Clinical Study of Mosaic Osteochondral Autologous Transplantation Versus Microfracture for the Treatment of Osteochondral Defects in the Knee Joint of Athletes

Background: Various techniques have proven to be effective for treating articular cartilage defect (ACD) and osteochondral defect (OCD) of the knee joint, but knowledge regarding which method is best still remains uncertain. Purpose: To evaluate and compare the outcomes of mosaic-type osteochondral autologous transplantation (OAT) and microfracture (MF) procedures for the treatment of articular cartilage defects of the knee joint in young active athletes. This article represents an update of the clinical results at 10 years. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: Between 1998 and 2002, a total of 60 athletes with a mean age of 24.3 years (range, 15-40 years) and with a symptomatic ACD or OCD in the knee were randomized to undergo either OAT or MF. Patients were then evaluated postoperatively using the International Cartilage Repair Society (ICRS) score, Tegner activity score, radiographs, and magnetic resonance imaging. The mean follow-up time was 10.4 years (range, 9-11 years). Results: Three to 10 years after the OAT and MF procedures, patients had lower ICRS and Tegner scores (P < .05), but both groups still had significant clinical improvement over presurgery scores according to ICRS scores at 10-year follow-up. Statistically significantly better results were detected in patients in the OAT group compared with those in the MF group at 10 years (P < .005). At 10-year follow-up, there were 15 failures (26%), including 4 failures (14%) of the OAT and 11 failures (38%) of MF treatment (P < .05). Seven patients (25%) from the OAT group and 14 patients (48%) from the MF group had radiographic evidence of Kellgren-Lawrence grade I osteoarthritis at 10 years, but these differences were not significant (P = .083) or related to the clinical results. The ICRS and Tegner scores of younger athletes (<25 years at the time of primary surgery) remained significantly higher after 10 years compared with older patients (P < .05); 15 of 20 patients (75%) in the OAT group and 8 of 22 patients (37%) in the MF group maintained the same physical activity level. Conclusion: The OAT technique for ACD or OCD repair in the athletic population allows for a higher rate of return to and maintenance of sports at the preinjury level compared with MF.

Microfracture for Osteochondral Lesions of the Talus

Background: Microfracture is recognized as a primary treatment strategy for osteochondral lesions of the talus up to 15 mm in size. The ability of fibrocartilage to withstand the mechanical loading of the joint over time is unknown. Purpose: The purpose of this study was to systematically review studies of microfracture for OLT and descriptively analyze the outcome data reported to determine whether it is consistent from one study to another and able to be pooled for systematic review. Methods: A systematic electronic search was performed using the MEDLINE and EMBASE databases. Studies that were published between January 1966 and June 2011 were included in the review. Only studies that reported data specifically on microfracture for treatment of osteochondral lesions of the talus and written in English were included in this review. Results: Twenty-four studies were included in this systematic review. The categories of general demographics and study design were generally well reported (each over 80% of studies). Patient history and patient-reported outcome data were reported less (55%-66%). Clinical variables (48%) and imaging data (39%) were the least reported in studies. Conclusion: There were gross inconsistencies and an underreporting of data between studies such that pooling was deemed impossible. A concerted effort must be made by investigators to ensure that there is adequate reporting of data in studies of microfracture treatment for OLT. A set of guidelines to assist surgeons in reporting data may be useful for future research.

Microfracture for Treatment of Knee Cartilage Defects in Children and Adolescents

Even though operative microfracture is the most frequent method for treatment of limited knee joint cartilage lesions among adults, data about ouctome in children and adolescents are rare. We performed a retrospective chart review and telephone interview to analyze for the clinical outcome following knee joint cartilage defect microfracturing among 10 children. Mean postoperative Lysholm was 92.1±9.9 and Tegner was 7.0±1.9. Clinical outcome differed across knee joint regions, as well as in dependence of varying pre-operative symptom duration, although this was not significant. Regression analysis did not reveal a significant impact of patient or defect characteristics on clinical outcome. Arthroscopic microfracturing for treatment of limited size symptomatic knee joint cartilage defects among children and adolescents is considered a reasonable surgical option. However, long-term outcome and larger patient cohorts are required.

Reoperative characteristics after microfracture of knee cartilage lesions in 454 patients

There is only limited information on those patients who fail following microfracture treatment at the knee joint. Evaluation was made of factors associated with treatment failure and clinical outcome assessment among this collective. The study included a total of 560 patients who had previously undergone microfracture for the treatment of symptomatic knee joint cartilage lesions. For the remainder of this study, inclusion criteria were patients that underwent reoperation at the initially operated knee joint (index knee) due to symptoms related to the primary site of microfracture intervention (failure patients) with a minimum postoperative follow-up of 2years. The remaining cohort of patients served as internal control (non-failure patients). Chart reviews were performed to identify patient and defect characteristics. Patients were evaluated for postoperative Lysholm knee scores, Tegner activity scale, as well as preoperative and postoperative numeric analogue scales (NAS) for function and pain (10=highest possible function, no pain). A total of 454/560 (81.1%) subjects were completely evaluated. Overall, 123/454 patients (26.9%) (age at operation 43.9±14.1years, 56 female, BMI 25.8±3.6, 30 smokers, 61.1±68.3month symptom duration, postoperative follow-up 5.0±2.1) met the inclusion criteria. The postoperative Lysholm score was 63.0±24.6 and the Tegner score was 4.0; NAS function improved from 2.8±1.8 to 4.8±2.2 (P<0.001), and NAS pain improved from 3.2±2.1 to 5.0±2.4 (P<0.001). Exclusively, the overall defect size/knee joint was smaller (P=0.006), postoperative follow-up was longer (P=0.002), and existense of previous surgery (77.2 vs. 51.6%, P<0.001) was more frequent in failure subjects when comparing to non-failure patients (n=331). The overall clinical outcome among failure subjects was significantly worse when comparing to non-failure subjects. Regression analysis identified that lower preoperative NAS values, being a smoker, and patello-femoral lesions were associated with a higher probability of reoperation. Within the collective presented here, microfracturing was associated with a high frequency of reoperation. Clinical outcome is worse when compared with that of patients without reoperation. Specific parameters can be identified that increase the eventuality of failure following microfracture treatment. IV.

Clinical Outcome of Autologous Chondrocyte Implantation for Failed Microfracture Treatment of Full-Thickness Cartilage Defects of the Knee Joint

Clinical Outcome of Autologous Chondrocyte Implantation for Failed Microfracture Treatment of Full-Thickness Cartilage Defects of the Knee Joint

Clinical Outcome of Autologous Chondrocyte Implantation for Failed Microfracture Treatment of Full-Thickness Cartilage Defects of the Knee Joint

Background: Although various factors have been identified that influence outcome after autologous chondrocyte implantation (ACI), the relevance of prior treatment of the cartilage defect and its effect concerning the outcome of second-line ACI have not been evaluated to a full extent. Hypothesis: Autologous chondrocyte implantation used as a second-line treatment after failed arthroscopic microfracturing is associated with a higher failure rate and inferior clinical results compared with ACI as a first-line treatment. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 28 patients with isolated cartilage defects at the knee joint were treated with ACI after microfracture as a first-line treatment had failed (failure defined as the necessity of reintervention). These patients were assigned to group A and compared with a matched-pair cohort of patients of identical age, defect size, and defect location (group B) in which ACI was used as a first-line treatment. Failure rates in both groups were assessed. Postoperative knee status was evaluated with the International Knee Documentation Committee (IKDC) score and Knee injury and Osteoarthritis Outcome Score (KOOS), and sporting activity was assessed by use of the Activity Rating Scale. Mean follow-up times were 48.0 months (range, 15.1-75.1 months) in group A and 41.4 months (range, 15.4-83.6 months) in group B. Differences between groups A and B were analyzed by Student t test. Results: Group A had significantly greater failure rates (7 of 28 patients) in comparison with group B (1 of 28 patients; P = .0241). Mean (SD) postoperative IKDC scores revealed 58.4 (22.4) points in group A with a trend toward higher score results (69.0 [19.1] points) for patients in group B (P = .0583). Significantly different results were obtained for KOOS pain and activity of daily living subscales, whereas the remaining KOOS subscales did not show significant differences. Despite the significantly higher failure rate observed in group A, those patients did not participate in fewer activities or perform physical activity less frequently or at a lower intensity. Conclusion: Autologous chondrocyte implantation after failed microfracturing appears to be associated with a significantly higher failure rate and inferior clinical outcome when compared with ACI as a first-line treatment.

Radiological evaluation of cartilage after microfracture treatment: A long-term follow-up study

Recent literature revealed good short-term results after microfracturing (MFX) of isolated focal cartilage defects in the knee joint. Study purpose was a long-term evaluation of patients who received MFX through a multimodal approach, correlating clinical scores and morphological pre- and postoperative MRI-scans. Between 2000 and 2007 158 patients were treated with MFX for focal femoral or tibial defects at our department. Patients with instabilities, secondary surgical intervention, patellofemoral lesions, a plica mediopatellaris or more than one cartilage defect site and age >55 were excluded. 15 patients were included. Minimum postoperative follow-up (FU) was 18 months (18-78 m). Mean age at surgery was 45 years (27-54), mean FU-interval 48 months (18-78 m). Male to female ratio was 9:6. For clinical assessment the Knee Osteoarthritis Ou tcome Score (KOOS) and Lysholm Score were used, radiological evaluation was performed with radiographs and 3Tesla-MRI. Clinical knee function was rated good to excellent in 1 patient, fair in 2 and poor in 10 patients. 2/15 patients received full knee replacement due to insufficient cartilage repair through MFX during FU period. Evaluation of pre- and postoperative MRI showed good cartilage repair tissue in 1 (7.7%), moderate repair in 2 (15.4%) and poor fill in 10 patients (76.9%). In these 10 patients the defect size increased. Average defect size preoperatively was 187 mm(2) (range 12-800 mm(2)) and postoperatively 294 mm(2) (40-800 mm(2)). The KOOS-Pain averaged 60 (39-94), KOOS-Symptoms 60.6 (21-100), KOOS-ADL 69 (21-91), KOOS-Sports 35.7 (5-60) and KOOS-QUL 37.2 (6-81). The average Lysholm Score was 73.9 (58-94). 10 patients showed a varus leg axis deviation (Ø 5.9°), 3 had a neutral alignment. The alignment correlated positively with KOOS and especially with the Lysholm Score. Our study demonstrated that MFX as a treatment option for cartilage defect in the knee did not show the anticipated clinical and radiological long-term results. In 12 of 15 patients the cartilage defect size had increased after MFX, in 2 patients indicating full-knee replacement. Especially those with a leg malalignment >5° in varus were more prone to suffer from an increase in defect size. In our cohort the clinical scores correlated with the radiological findings.

Thrombospondin-1 Prevents Excessive Ossification in Cartilage Repair Tissue Induced by Osteogenic Protein-1

This study investigated the effect of thrombospondin-1 (TSP-1) on the formation of cartilage repair tissue in combination with stimulation by osteogenic protein-1 (OP-1). In miniature pigs, articular cartilage lesions in the femoral trochlea were treated by the microfracture technique and either received no further treatment (MFX), or were treated by additional application of recombinant osteogenic protein-1 (MFX+OP-1), recombinant TSP-1 (MFX+TSP-1), or a combination of both proteins (MFX+TSP-1+OP-1). Six and 26 weeks after surgery, the repair tissue and the degree of endochondral ossification were assessed by histochemical and immunohistochemical methods detecting collagen types I, II, X, TSP-1, and CD31. Microfracture treatment merely induced the formation of inferior fibrocartilaginous repair tissue. OP-1 stimulated chondrogenesis, but also induced chondrocyte hypertrophy, characterized by synthesis of collagen type X, and excessive bone formation. Application of TSP-1 inhibited inadvertant endochondral ossification, but failed to induce chondrogenesis. In contrast, the simultaneous application of both TSP-1 and OP-1 induced and maintained a permanent, nonhypertrophic chondrocyte-like phenotype within cartilage repair tissue. The data of this study demonstrate that OP-1 and TSP-1 complement each other in a functional manner. While OP-1 induces chondrogenesis of the ingrowing cells, TSP-1 prevents their further hypertrophic differentiation and prevents excessive endochondral ossification within the lesions.

Low oxygen tension is a more potent promoter of chondrogenic differentiation than dynamic compression

During fracture healing and microfracture treatment of cartilage defects mesenchymal stem cells (MSCs) infiltrate the wound site, proliferate extensively and differentiate along a cartilaginous or an osteogenic lineage in response to local environmental cues. MSCs may be able to directly sense their mechanical environment or alternatively, the mechanical environment could act indirectly to regulate MSC differentiation by inhibiting angiogenesis and diminishing the supply of oxygen and other regulatory factors. Dynamic compression has been shown to regulate chondrogenesis of MSCs. In addition, previous studies have shown that a low oxygen environment promotes in vitro chondrogenesis of MSCs. The hypothesis of this study is that a low oxygen environment is a more potent promoter of chondrogenic differentiation of MSCs embedded in agarose hydrogels compared to dynamic compression. In MSC-seeded constructs supplemented with TGF-β3, GAG and collagen accumulation was higher in low oxygen conditions compared to normoxia. For normoxic and low oxygen culture GAG accumulation within the agarose hydrogel was inhomogeneous, with low levels of GAG measured in the annulus of constructs maintained in normoxic conditions. Dynamic compression did not significantly increase GAG or collagen accumulation in normoxia. However under low oxygen conditions, dynamic compression reduced GAG accumulation compared to free-swelling controls, but remained higher than comparable constructs maintained in normoxic conditions. This study demonstrates that continuous exposure to low oxygen tension is a more potent pro-chondrogenic stimulus than 1 h/day of dynamic compression for porcine MSCs embedded in agarose hydrogels.

Cell-Laden and Cell-Free Matrix-Induced Chondrogenesis versus Microfracture for the Treatment of Articular Cartilage Defects: A Histological and Biomechanical Study in Sheep.

Objective:The aim of this study was to evaluate the regenerative potential of cell-laden and cell-free collagen matrices in comparison to microfracture treatment applied to full-thickness chondral defects in an ovine model.Methods:Animals (n = 30) were randomized into 5 treatment groups, and 7-mm full-cartilage-thickness defects were set at the trochlea and medial condyle of both knee joints and treated as follows: 2 scaffolds in comparison (collagen I/III, Chondro-Gide®; collagen II, Chondrocell®) for covering microfractured defects (autologous matrix-induced chondrogenesis), both scaffolds colonized in vitro with autologous chondrocytes (matrix-associated chondrocyte transplantation), or scaffold-free microfracture technique. One year after surgery, cartilage lesions were biomechanically (indentation test), histologically (O’Driscoll score), and immunohistochemically (collagen type I and II staining) evaluated.Results:All treatment groups of the animal model induced more repair tissue and showed better histological scores and biomechanical properties compared to controls. The average thickness of the repair tissue was significantly greater when a scaffold was used, especially the collagen I/III membrane. However, none of the index procedures surpassed the others from a biomechanical point of view or based on the histological scoring. Collagen type II expression was better in condylar defects compared to the trochlea, especially in those treated with collagen I/III membranes.Conclusion:Covering of defects with suitable matrices promotes repair tissue formation and is suggested to be a promising treatment option for cartilage defects. However, it failed to improve the biomechanical and histological properties of regenerated articular cartilage compared to microfracture alone in an ovine model under the given circumstances.

Microfracture treatment of single or multiple articular cartilage defects of the knee: a 5-year median follow-up of 110 patients

We compared the results of microfracture in single versus multiple symptomatic articular cartilage defects in the knee in 110 patients with a median age of 38 years (range 15-60). Cases of reoperation of the cartilage defect were classified as failures. Clinical outcome in non-failures was evaluated by the Lysholm score and grading of knee pain and function of the knee by the use of patient-administered visual analog scales (VAS; 0-100). Data were prospectively collected before the operation and at the 2- to 9-year follow-up. The single lesion or the largest of multiple lesions were located on the medial femoral condyle (n = 62), trochlea (n = 18), lateral tibia (n = 11), patella (n = 10) or lateral femoral condyle (n = 9). We treated one (n = 76), two (n = 27) or three (n = 7) lesions with a median total area of 4 cm(2) (range 1-15). A total of 24 failures (22%) were registered-18% in the single-defect subgroup and 29% in the multiple-defects subgroup. In the remaining group of patients (n = 86), the mean Lysholm score, mean pain-score (0 = no pain; 100 = worst possible pain) and mean function-score (0 = useless; 100 = full function) improved from 51, 52 and 41, respectively, to 71 (P < 0.001), 30 (P < 0.001) and 69 (P < 0.001) at the follow-up. The pain-score was significant lower (P = 0.042), and the function-score significantly higher (P = 0.001) in the group of patients with a single lesion compared to the group with 2 or 3 lesions. The Lysholm score did not differ significantly between the two subgroups (P = 0.06).

Development of a new method to harvest chondroprogenitor cells from underneath cartilage defects in the knees

BackgroundMesenchymal progenitor cells from bone marrow hold great potential as a cell source for cartilage repair. Aspiration from the iliac crest is the most widely used method to harvest bone marrow cells for cartilage repair. The objective of our study was to establish a new method to isolate mesenchymal progenitor cells by direct aspiration of bone marrow from the subchondral spongious bone underneath cartilage defects during microfracture treatment and to confirm the chondrogenic potential of the resulting cell cultures. MethodsBone marrow was aspirated arthroscopically from patients treated for isolated cartilage defects. Adherent stromal cells were isolated, expanded in monolayer cultures, and characterized by flow cytometry. Chondrogenic induction of cells was achieved by combination of spheroid cultures in hanging drops and the concomitant use of transforming growth factor-P (TGFP). Articular chondrocytes established in threedimensional (3D) cultures were used as positive cartilageforming units, and skin fibroblasts were used as negative controls. Three-dimensional constructs were stained for immunohistochemical and histological examination, and a real-time polymerase chain reaction (PCR) was performed to quantify the expression of aggrecan, collagen types 1 and 2, and Sox9. ResultsMesenchymal stem cell-like progenitor cells (MSCs) displaying chondrogenic differentiation capacity were harvested arthroscopically from underneath cartilage lesions on distal femurs using the one-hole technique. Stem cell-related surface antigens analyzed by flow cytometry confirmed the nature of the isolated adherent cells. MSC spheroids stained positive for glycosaminoglycans and collagen type 2. Realtime PCR showed that MSCs in 3D spheroids significantly increased gene expression of collagen type 2, aggrecan, and Sox 9 and down-regulated expression of collagen type 1 when compared to the mRNA levels measured in MSCs monolayers. ConclusionsWe describe a new technique that may be applied for harvesting bone marrow cells from cartilage defects during arthroscopic intervention of the knee. Cells harvested in this way hold full chondrogenic differentiation potential. Our data imply that MSC storage may be established by using marrow from this approach, bypassing the need for cell aspiration from the iliac crest.

Matrix‐guided cartilage regeneration in chondral defects

Small cartilage defects treated with microfracture show comparable clinical results to those treated with ACI (autologous chondrocyte implantation). Unfortunately, the regenerative tissue generated by microfracture treatment does not exhibit the structure and function of hyaline articular cartilage. Adult mesenchymal stem cells are supposed to be capable of differentiating according to mechanical stimuli, e.g. into chondrocytes, thus generating hyaline cartilage. The treatments used so far, such as the microfracture procedure, are only able to induce mechanically insufficient fibrocartilage. The purpose of the present study was to test the influence of a resorbable implant manufactured from PGLA (polyglycollic-co-lactic acid) fleece in combination with microfracture in the weight-bearing area of the femoral condyle of mature sheep on cartilage repair. Artificial chondral defects (diameter: 8 mm) were created and treated with microfracture, with a PGLA implant alone or with a combination of both (n=6 for each group). Untreated empty defects served as controls. Under thorough pain control, full weight bearing was permitted immediately after the operation. After 12 weeks, the animals were killed and the operated knees were removed and histologically processed. First, the degree of covering of the defect with regenerative tissue was measured; then, the quality of the regenerate was evaluated using the score of O'Driscoll, Keeley and Salter [(1986) J. Bone Joint Surg. Am. 68, 1017-1035], which was modified to include histochemical labelling results. The combination of PGLA implant and microfracture led to a significant improvement of the quality of the regenerate when compared with microfracturing alone.

Formation of cartilage repair tissue in articular cartilage defects pretreated with microfracture and covered with cell‐free polymer‐based implants

The aim of our study was to evaluate the mid-term outcome of a cell-free polymer-based cartilage repair approach in a sheep cartilage defect model in comparison to microfracture treatment. Cell-free, freeze-dried implants (chondrotissue) made of a poly-glycolic acid (PGA) scaffold and hyaluronan were immersed in autologous serum and used for covering microfractured full-thickness articular cartilage defects of the sheep (n = 4). Defects treated with microfracture only served as controls (n = 4). Six months after implantation, cartilage implants and controls were analyzed by immunohistochemical staining of type II collagen, histological staining of proteoglycans, and histological scoring. Histological analysis showed the formation of a cartilaginous repair tissue rich in proteoglycans. Histological scoring documented significant improvement of repair tissue formation when the defects were covered with the cell-free implant, compared to controls treated with microfracture. Immunohistochemistry showed that the cell-free implant induced cartilaginous repair tissue and type II collagen. Controls treated with microfracture showed marginal formation of a mixed-type repair tissue consisting of cartilaginous tissue and fibro-cartilage. Covering of microfractured defects with the cell-free polymer-based cartilage implant is suggested to be a promising treatment option for cartilage defects and improves the regeneration of articular cartilage.

A Randomized Trial Comparing Autologous Chondrocyte Implantation with Microfracture

Background: The optimal treatment for cartilage lesions has not yet been established. The objective of this randomized trial was to compare autologous chondrocyte implantation with microfracture. This paper represents an update, with presentation of the clinical results at five years. Methods: Eighty patients who had a single chronic symptomatic cartilage defect on the femoral condyle in a stable knee without general osteoarthritis were included in the study. Forty patients were treated with autologous chondrocyte implantation, and forty were treated with microfracture. We used the International Cartilage Repair Society, Lysholm, Short Form-36, and Tegner forms to collect clinical data, and radiographs were evaluated with use of the Kellgren and Lawrence grading system. Results: At two and five years, both groups had significant clinical improvement compared with the preoperative status. At the five-year follow-up interval, there were nine failures (23%) in both groups compared with two failures of the autologous chondrocyte implantation and one failure of the microfracture treatment at two years. Younger patients did better in both groups. We did not find a correlation between histological quality and clinical outcome. However, none of the patients with the best-quality cartilage (predominantly hyaline) at the two-year mark had a later failure. One-third of the patients in both groups had radiographic evidence of early osteoarthritis at five years. Conclusions: Both methods provided satisfactory results in 77% of the patients at five years. There was no significant difference in the clinical and radiographic results between the two treatment groups and no correlation between the histological findings and the clinical outcome. One-third of the patients had early radiographic signs of osteoarthritis five years after the surgery. Further long-term follow-up is needed to determine if one method is better than the other and to study the progression of osteoarthritis. Level of Evidence: Therapeutic Level I. See Instructions to Authors for a complete description of levels of evidence.

A Randomized Trial Comparing Autologous Chondrocyte Implantation with Microfracture

The optimal treatment for cartilage lesions has not yet been established. The objective of this randomized trial was to compare autologous chondrocyte implantation with microfracture. This paper represents an update, with presentation of the clinical results at five years. Eighty patients who had a single chronic symptomatic cartilage defect on the femoral condyle in a stable knee without general osteoarthritis were included in the study. Forty patients were treated with autologous chondrocyte implantation, and forty were treated with microfracture. We used the International Cartilage Repair Society, Lysholm, Short Form-36, and Tegner forms to collect clinical data, and radiographs were evaluated with use of the Kellgren and Lawrence grading system. At two and five years, both groups had significant clinical improvement compared with the preoperative status. At the five-year follow-up interval, there were nine failures (23%) in both groups compared with two failures of the autologous chondrocyte implantation and one failure of the microfracture treatment at two years. Younger patients did better in both groups. We did not find a correlation between histological quality and clinical outcome. However, none of the patients with the best-quality cartilage (predominantly hyaline) at the two-year mark had a later failure. One-third of the patients in both groups had radiographic evidence of early osteoarthritis at five years. Both methods provided satisfactory results in 77% of the patients at five years. There was no significant difference in the clinical and radiographic results between the two treatment groups and no correlation between the histological findings and the clinical outcome. One-third of the patients had early radiographic signs of osteoarthritis five years after the surgery. Further long-term follow-up is needed to determine if one method is better than the other and to study the progression of osteoarthritis.

High-Impact Athletics after Knee Articular Cartilage Repair

Background Knee articular cartilage injuries in athletes present a therapeutic challenge and have been identified as an important cause of permanent disability because of the high mechanical joint stresses in athletes. Purpose To determine whether microfracture treatment of knee articular cartilage injuries can return athletes to high-impact sports and to identify the factors that affect the ability to return to athletic activity. Study Design Case series; Level of evidence, 4. Methods Thirty-two athletes who regularly participated in high-impact, pivoting sports before articular cartilage injury were treated with microfracture for single articular cartilage lesions of the knee. Functional outcome was prospectively evaluated with a minimum 2-year follow-up by subjective rating, activity-based outcome scores, and the ability for postoperative participation in high-impact, pivoting sports. Results At last follow-up, 66% of athletes reported good or excellent results. Activity of daily living, Marx activity rating scale, and Tegner activity scores increased significantly after microfracture. After an initial improvement, score decreases were observed in 47% of athletes. Forty-four percent of athletes were able to regularly participate in high-impact, pivoting sports, 57% of these at the preoperative level. Return to high-impact sports was significantly higher in athletes with age <40 years, lesion size <200 mm2, preoperative symptoms <12 months, and no prior surgical intervention. Conclusion Microfracture is an effective first-line treatment to return young athletes with short symptomatic intervals and small articular cartilage lesions of the knee back to high-impact athletics.

Fourier transform infrared imaging spectroscopy investigations in the pathogenesis and repair of cartilage

Significant complications in the management of osteoarthritis (OA) are the inability to identify early cartilage changes during the development of the disease, and the lack of techniques to evaluate the tissue response to therapeutic and tissue engineering interventions. In recent studies several spectroscopic parameters have been elucidated by Fourier transform infrared imaging spectroscopy (FT-IRIS) that enable evaluation of molecular and compositional changes in human cartilage with progressively severe OA, and in repair cartilage from animal models. FT-IRIS permits evaluation of early-stage matrix changes in the primary components of cartilage, collagen and proteoglycan on histological sections at a spatial resolution of ∼6.25 μm. In osteoarthritic cartilage, the collagen integrity, monitored by the ratio of peak areas at 1338 cm −1/Amide II, was found to correspond to the histological Mankin grade, the gold standard scale utilized to evaluate cartilage degeneration. Apparent matrix degradation was observable in the deep zone of cartilage even in the early stages of OA. FT-IRIS studies also found that within the territorial matrix of the cartilage cells (chondrocytes), proteoglycan content increased with progression of cartilage degeneration while the collagen content remained the same, but the collagen integrity decreased. Regenerative (repair) tissue from microfracture treatment of an equine cartilage defect showed significant changes in collagen distribution and loss in proteoglycan content compared to the adjacent normal cartilage, with collagen fibrils demonstrating a random orientation in most of the repair tissue. These studies demonstrate that FT-IRIS is a powerful technique that can provide detailed ultrastructural information on heterogeneous tissues such as diseased cartilage and thus has great potential as a diagnostic modality for cartilage degradation and repair.

A novel method for determination of collagen orientation in cartilage by Fourier transform infrared imaging spectroscopy (FT-IRIS)

The orientation of collagen molecules is an important determinant of their functionality in connective tissues. The objective of the current study is to establish a method to determine the alignment of collagen molecules in histological sections of cartilage by polarized Fourier transform infrared imaging spectroscopy (FT-IRIS), a method based on molecular vibrations. Polarized FT-IRIS data obtained from highly oriented tendon collagen were utilized to calibrate the derived spectral parameters. The ratio of the integrated areas of the collagen amide I/II absorbances was used as an indicator of collagen orientation. These data were then applied to FT-IRIS analysis of the orientation of collagen molecules in equine articular cartilage, in equine repair cartilage after microfracture treatment, and in human osteoarthritic cartilage. Polarized light microscopy (PLM), the most frequently utilized technique to evaluate collagen fibril orientation in histological sections, was performed on picrosirius red-stained sections for comparison. Thicknesses of each zone of normal equine cartilage (calculated based on differences in collagen orientation) were equivalent as determined by PLM and FT-IRIS. Comparable outcomes were obtained from the PLM and FT-IRIS analyses of repair and osteoarthritis tissues, whereby similar zonal variations in collagen orientation were apparent for the two methods. However, the PLM images of human osteoarthritic cartilage showed less obvious zonal discrimination and orientation compared to the FT-IRIS images, possibly attributable to the FT-IRIS method detecting molecular orientation changes prior to their manifestation at the microscopic level.