Retrograde cartilage transplantation on the proximal and distal tibia

Tibial Plateau Cartilage Lesions: A Systematic Review of Techniques, Outcomes, and Complications

OBJECTIVE

The purpose of this systematic review is to determine (1) current reported treatment options for isolated tibial plateau (TP) cartilage lesions, (2) patient reported outcomes following various treatments, and (3) complication rate and survivorship following various treatments.

DESIGN

A literature search of PubMed, the Cochrane Library, and CINAHL was conducted adhering to PRISMA guidelines. Patients were included if they had TP cartilage lesions treated with surgery. Lesion characteristics, surgical procedure details, patient reported outcomes, complication, and failure rates were collected.

RESULTS

Thirteen studies yielded 205 knees with TP cartilage lesions treated surgically. Ages ranged from 12 to 77 years. Surgical techniques included 138 treated with osteochondral allograft transplantation (OCA), 37 treated with osteochondral autograft transfer system (OATS), 11 treated with microfracture, 11 treated with an osteochondral scaffold, and 8 treated with autologous chondrocyte implantation (ACI). The patient-reported outcome measures were heterogeneous, but all reported improvements with the notable exception of one study evaluating microfracture. The rate of complications ranged from 0% to 4.6%. Failure rate ranged from 22% to 46% for OCA and 0% to 16% for OATS. No failures were reported for the additional techniques.

CONCLUSIONS

Various surgical techniques have been utilized for the treatment of TP cartilage lesions. Patient-reported outcome measures were heterogeneous, but improvements were reported following all surgical treatments except for microfracture, which resulted in decreased scores at mid-term follow-up. The complication rate was low for all techniques described. However, the failure rate was higher following unicondylar OCA for salvage treatment of posttraumatic deformities.

Surgical Treatment of Osteochondral Lesions of the Tibial Plafond: A Systematic Review and Meta-Analysis

BACKGROUND

The literature on osteochondral lesions of the tibial plafond (OLTPs) is sparse. The aim of this study was therefore to provide an overview of clinical and radiological outcomes following treatment of OLTPs.

METHODS

We performed a systematic search of the MEDLINE, Embase, and Cochrane library databases. The review was performed in accordance with the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines and included all original articles on treatment outcomes for OLTPs. The methodological quality of the articles was assessed using the Methodological Index for Non-Randomized Studies (MINORS). Baseline patient and lesion characteristics were pooled and weighted according to the number of lesions per study. The primary outcome was any clinical or patient-reported outcome measure pooled by treatment method when separable data were available. Secondary outcomes were complications, reoperation rates, radiological outcomes, and sport outcomes.

RESULTS

The search yielded 2,079 articles, of which 10 studies (1 prospective case series, 1 retrospective comparative study, and 8 retrospective case series) with a total of 175 patients were included. The overall methodological quality of the studies was low. All patients were treated surgically; 96% of the lesions were primary cases (i.e., first-time surgery) and 58% were solitary tibial lesions (i.e., no opposing talar lesion). Arthroscopic bone marrow stimulation was the most frequently used treatment strategy (51%), followed by cartilage transplantation (17%), chondrogenesis-inducing techniques (11%), osteochondral transplantation (3%), retrograde drilling (3%), and mixed (i.e., inseparable) treatments (15%). The clinical outcomes of the different surgical therapies were considered to be moderate to good. The pooled postoperative AOFAS (American Orthopaedic Foot & Ankle Society) score for bone marrow stimulation and osteochondral transplantation was 54.8 (95% confidence interval [CI], 49.5 to 85.0) (n = 14) and 85.3 (95% CI, 56 to 100) (n = 3), respectively. Overall, complications and reoperations were rarely reported. The pooled complication and reoperation rates could only be calculated for bone marrow stimulation and were 5% and 7%, respectively.

CONCLUSIONS

Surgical interventions for OLTPs appear to yield moderate to good clinical outcomes. Bone marrow stimulation resulted in a moderate AOFAS score. Complications and reintervention rates were found to be low. The current evidence in the literature is limited because of the underreporting of clinical, radiological, and sport data and the heterogenous outcome scores reported.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Osteochondral Lesions of the Distal Tibial Plafond: A Systematic Review of Lesion Locations and Treatment Outcomes

BACKGROUND

Osteochondral lesions of the tibial plafond (OLTPs) remain less common than osteochondral lesions of the talus (OLTs), but recognition of the condition has increased.

PURPOSE

To systematically evaluate the literature on lesion locations and treatment outcomes of OLTPs, whether in isolation or in combination with OLTs.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A search was performed using the PubMed, Embase, and CINAHL databases for studies on lesion locations or with imaging or treatment outcomes of OLTPs. Case reports and reports based on expert opinion were excluded. Lesion locations as well as outcome measure results were aggregated. The Methodological Index for Non-randomized Studies score was used to assess methodological quality when applicable.

RESULTS

Included in this review were 10 articles, all published in 2000 or later. Most studies were evidence level 4, and the mean Methodological Index for Non-randomized Studies score was 8.6 (range, 8-10). Overall, 174 confirmed OLTP cases were identified, and the mean patient age was 38.8 years. Of the 157 lesions with confirmed locations, the most common was central-medial (32/157; 20.4%). Of 6 studies on treatment outcomes, all but 1 evaluated bone marrow stimulation techniques. Microfracture of small lesions (<150 mm2) was the most common treatment utilized. Imaging and functional outcomes appeared favorable after treatment. The data did not support differences in outcomes between isolated OLTPs and OLTPs with coexisting OLTs.

CONCLUSION

Osteochondral lesions of the distal tibia most commonly occurred at the central-medial tibial plafond. Microfracture of small lesions was the most common treatment utilized, and clinical and magnetic resonance imaging results were favorable, although data were heterogeneous. Areas for future research include the following: the effect of patient factors and additional pathologies on outcomes; larger or deeper lesion treatment; more direct comparisons of outcomes between kissing or coexisting lesions and isolated lesions; and head-to-head comparison of treatments, such as microfracture, bone marrow-derived cell transplantation, and osteochondral autografts/allografts.

Safety, Feasibility, and Radiographic Outcomes of the Anterior Meniscal Takedown Technique to Approach Chondral Defects on the Tibia and Posterior Femoral Condyle: A Matched Control Study

OBJECTIVE

Takedown of the anterior meniscus to facilitate exposure of the cartilage defects located on the tibial plateau and/or posterior femoral condyle with subsequent reattachment is being performed clinically; however, clinical evidence is lacking to support the safety of this technique. The aim of this study was therefore to investigate whether meniscal extrusion develops after patients undergo meniscus takedown and transosseous refixation during autologous chondrocyte implantation (ACI).

DESIGN

We analyzed data from 124 patients with a mean follow-up of 6.8 ± 2.5 years. Sixty-two patients who underwent (ACI) with anterior meniscus takedown and refixation by the senior surgeon (TM), were compared with a matched control group of patients who underwent ACI without meniscus takedown. Meniscal extrusion was investigated by measuring the absolute value and the relative percentage of extrusion (RPE) on 1.5-T magnetic resonance images (MRI) at final follow-up. The number of menisci with radial displacement greater or lesser than 3 mm was determined. In cases where a preoperative MRI was available, both pre- and postoperative meniscal extrusion was evaluated (n = 30) in those patients undergoing meniscal takedown.

RESULTS

There was no significant difference in either absolute meniscus extrusion, RPE, or extrusion rate in patients with and without meniscus takedown. Among patients with meniscal takedown and both pre- and postoperative MRI scans, absolute meniscus extrusion, RPE, and extrusion rate showed no significant differences.

CONCLUSION

Meniscal takedown and subsequent transosseous refixation is a safe and effective technique for exposure of the tibial plateau and posterior femoral condyle.

Arthroscopic versus Open Osteochondral Autograft Transplantation (Mosaicplasty) for Cartilage Damage of the Knee: A Systematic Review

Osteochondral autograft transplantation (OAT) is a surgical option for repairing cartilage damage in knees, and can be performed using open or arthroscopic procedures. The aim of this review was to report clinical outcomes, postoperative complications, defect location, and defect size between open and arthroscopic OATs. Three electronic databases (EMBASE, PUBMED, and MEDLINE) were searched for relevant articles. In regard to eligibility criteria, knee articular damage cases solely treated with OAT were included and cases concomitant with ligament reconstruction, limb realignment, and meniscus repair were excluded. The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and descriptive statistics are presented. A total of 24 studies were included with a total sample of 1,139 patients (532 in open OAT vs. 607 in arthroscopic OAT). Defect size in open OAT was three times larger than that of arthroscopic OAT (2.96 ± 0.76 vs. 0.97 ± 0.48 cm²). In terms of defect location, the medial femoral condyle (MFC) was the most common (75.4%), followed by the lateral femoral condyle (LFC; 12.1%), patella (6.7%), and trochlea (5.7%). All of these defect locations were treated with open OAT, whereas arthroscopic OAT treatments were restricted to the MFC and LFC. The clinical outcomes were overall favorable with the modified Hospital for Special Surgery knee scores being 89.6 ± 8.0 (36.1-month follow-up) versus 90.4 ± 6.0 (89.5-month follow-up) and the Lysholm scores being 81.6 ± 8.9 (44.2-month follow-up) and 83.3 ± 7.4 (12.0-month follow-up) between open and arthroscopic OATs, respectively. Fifty-three postoperative complications were observed (39/279 vs. 14/594) and the most common complication was hemarthrosis (13/39 in open, vs. 1/14 in arthroscopic OAT). The overall clinical outcomes were favorable in open and arthroscopic OATs, whereas open OAT allowed for treatment of lesions approximately three times greater in dimension than in arthroscopic OAT. Also, defect location was restricted to MFC and LFC in arthroscopic OAT. The most common complication was hemarthrosis.

Osteochondral lesion of the tibial plafond treated with a retrograde osteochondral autograft: a report of two cases

Background

Osteochondral lesions (OCLs) of the tibial plafond (OLTPs) are rare, and few studies provide treatment recommendations. We describe two cases of an OLTP that were treated with retrograde osteochondral autograft.

Case Reports

The first case was a 27-year-old basketball player and the second case was a 38-year-old soccer player. We harvested osteochondral autografts from the nonweight-bearing area of the lateral femoral condyle of the patient’s ipsilateral knees. The grafts were reversed and inserted into the bone tunnel reaching the OLTPs starting proximally and moving distally. The first patient was able to play professional basketball 14 months after the procedure and continues to play 5 years and 6 months later. The second patient was able to play recreational soccer 9 months after the procedure and continues to play 4 years later.

Conclusion

Use of the retrograde osteochondral autograft produced satisfactory results including the return to sports. The retrograde osteochondral autograft can be considered recommendable for treating OLTPs.

Arthroscopic Management of Isolated Tibial Plateau Defect With Microfracture and Micronized Allogeneic Cartilage-Platelet-Rich Plasma Adjunct

Articular cartilage lesions of the tibial plateau are an uncommonly encountered clinical entity, and they have been comparatively less well studied than femoral condyle or patellofemoral defects. The management of these lesions is complicated by the challenging geometry, difficult surgical approach, and proximity to important anatomic structures, and thus, treating these lesions by previously established methods, such as osteochondral allograft transplantation or osteochondral autograft transfer, can be a technically challenging endeavor. These lesions remain readily available to undergo microfracture, and this is the preferred method of management in the senior author's practice. Although less technically difficult and less invasive than other techniques, microfracture is currently limited by concerns over the long-term durability of the method. Current research seeks to improve the quality of cartilage fill stimulated by microfracture, and adjunct techniques have become increasingly popular. In this technical report, we present a technique for arthroscopic treatment of an isolated tibial plateau defect with microfracture using a micronized allogeneic cartilage (BioCartilage; Arthrex, Naples, FL) and platelet-rich plasma adjunct.

Surgical Technique and Clinical Outcomes of Retrograde Osteochondral Autograft Transfer for Osteochondral Lesions of the Tibial Plateau

PURPOSE

To present the surgical technique, clinical outcomes, and poor prognostic factors of arthroscopic retrograde osteochondral autograft transfer of the tibial plateau.

METHODS

Twelve patients (6 men, 6 women; mean age, 38.7 years) with tibial plateau osteochondral lesions underwent surgery. The primary diseases were osteonecrosis in 4 cases, cartilage injuries in 6, and postfractures of the tibial plateau in 2. Clinical outcomes were evaluated preoperatively and postoperatively according to the International Knee Documentation Committee score and the Japanese Orthopaedic Association score. The International Cartilage Repair Society score was recorded in 7 cases who underwent second-look arthroscopies postoperatively. Statistical analyses were performed to identify prognostic factors associated with the clinical outcomes.

RESULTS

The mean International Knee Documentation Committee and Japanese Orthopaedic Association scores were both significantly improved from 39.0 (range, 13.0-57.1) to 72.4 (range, 33.3-100) (P = .0022) and from 65.8 (range, 30.0-85.0) to 85.8 (range, 50.0-100) (P = .0022 < .05), respectively. In 2 cases, secondary operations were performed because of knee pain (1 varus osteotomy of the femur and 1 total knee replacement). The mean International Cartilage Repair Society scores were significantly worse in the 2 cases who required a secondary operation (3.5; abnormal) than in the 5 cases who did not (10.6; nearly normal). The secondary operation rate was significantly higher in cases with lesion size ≥400 mm² than in those <400 mm² (Fisher's exact test; P = .046).

CONCLUSIONS

Most clinical scores improved significantly postoperatively. The results indicate that arthroscopic retrograde osteochondral autograft transfer is an effective procedure to achieve sufficient cartilage congruity for osteochondral lesions of the tibial plateau <400 mm² in size.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Osteochondral lesion of lateral tibial plateau with extrusion of lateral meniscus treated with retrograde osteochondral autograft transplantation and arthroscopic centralisation

BACKGROUND

Extrusion of the meniscus has been reported to be correlated with progression of osteoarthritis. In cases with osteochondral lesions after extrusion of the meniscus, meniscal transplantation was the only surgical intervention. Recently, a novel procedure called arthroscopic centralisation has been developed to restore the meniscus function by centralising the midbody of the extruded meniscus onto the rim of the tibial plateau using suture anchors.

CASE REPORT

A combination of novel techniques-retrograde osteochondral autograft transplantation to retain hyaline articular cartilage and arthroscopic centralisation to restore residual meniscal function-was used to repair an osteochondral lesion of the lateral tibial plateau possibly caused by extrusion of the lateral meniscus. Good clinical and radiographic outcomes were achieved at the 2-year follow-up.

CONCLUSION

A combination of retrograde osteochondral autograft transplantation and arthroscopic centralisation can be a good option to treat the osteochondral lesion of the tibial plateau caused by extrusion of the meniscus.

Medial Malleolar Osteotomy and Osteochondral Autograft Transfer for Osteochondritis Dissecans of the Distal Tibial Plafond

The literature on the surgical treatment of osteochondritis dissecans of the distal tibial plafond is significantly limited. The purpose of this case study is to present a novel surgical technique to repair osteochondritis dissecans of the distal medial tibial plafond. A retrospective chart and radiographic review of a 15-year-old male was performed with a 24-month follow-up along with a review of the literature. A right angled medial malleolar osteotomy provides adequate exposure, width, and depth of the medial distal tibial plafond allowing for the successful transfer of osteochondral autograft plugs.

LEVELS OF EVIDENCE

Therapeutic, Level IV: Case report.

An anterior ankle arthroscopic technique for retrograde osteochondral autograft transplantation of posteromedial and central talar dome cartilage defects

PURPOSE

The purpose of this study was to present an arthroscopic technique for the treatment for posteromedial and central cartilage defects of the talus using anterior arthroscopic portals and without performing a medial malleolar osteotomy.

METHODS

Nine fresh cadavers were dissected. Autografts were implanted under arthroscopy using a retrograde osteochondral transplantation system, and their position was estimated using specific angular calibrators and later confirmed by software analysis of two photographs of the disarticulated ankle joint.

RESULTS

In eight cases, the congruence between the surrounding articular cartilage and the cartilage of the graft was high, with differences measuring <1 mm. There were no iatrogenic cartilage lesions of the tibial plafond and no fractures of the talus. All the autografts remained stable during full range of motion cycles of the ankle joint. One failure was reported.

CONCLUSION

This cadaveric study showed that the retrograde osteochondral autograft transplantation technique in the talus is feasible. It can be used to restore the posteromedial and central talar articular surfaces using conventional ankle arthroscopic instrumentation and anterior arthroscopic portals without resorting to a medial malleolar osteotomy. Further clinical and biomechanical studies are required to prove the efficacy of this technique and its reproducibility in routine clinical practice.

Articular cartilage repair: procedures versus products

This review discusses the current perspectives and practices regarding the treatment of articular cartilage injury. Specifically, the authors have delineated and examined articular cartilage repair techniques as either surgical procedures or manufactured products. Although both methodologies are used to treat articular cartilage injury, there are obvious advantages and disadvantages to the application of both, with the literature providing few recommendations on the most suitable regimen for the patient and surgeon. In recent times, cell-based tissue engineering products, predominantly autologous chondrocyte implantation, have been the subject of much research and have become clinically popular. Herein, we review the most used procedures and products in cartilage repair, compare and contrast their outcomes, and evaluate the issues that must be overcome in order to improve patient efficacy in the future.

Arthroscopic retrograde osteochondral autograft transplantation for cartilage lesions of the tibial plateau: a prospective study

BACKGROUND

There are only 2 reported cases of arthroscopic retrograde osteochondral autograft transplantations regarding tibial plateau cartilage defects.

PURPOSE

To present a detailed description of arthroscopic retrograde osteochondral autograft transplantation of the tibial plateau as well as to provide its advantages and disadvantages in comparison with other techniques.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Four patients (3 men and 1 woman; mean age, 31.2 years) suffering from tibial plateau cartilage lesions underwent surgery. In each case, the lesions were caused by sports injuries. There were 3 lateral and 1 medial tibial plateau defects. The International Knee Documentation Committee (IKDC) score and Knee injury and Osteoarthritis Outcome Score (KOOS) were recorded preoperatively and postoperatively. Radiological assessment was made by plain radiographs, CT arthroscans, and MRI.

RESULTS

The mean follow-up was 55 months (range, 52-60). The mean preoperative IKDC score was 53.5 (range, 37-66), while the mean postoperative IKDC score at final follow-up was 95.4 (range, 93.1-97.7). Regarding the KOOS calculation, there was significant improvement concerning each parameter after surgery. All patients were satisfied with the surgical procedure and returned to their previous activity level. Postoperative imaging showed very good adaptation and incorporation of the osteochondral autografts.

CONCLUSION

Treatment of tibial plateau cartilage defects with arthroscopic retrograde osteochondral autograft transplantation could be performed on a routine basis in clinical practice. The results were encouraging and showed good incorporation of the graft, a minimal failure rate, and satisfactory functional outcomes of patients.

Reconstruction of a large osteochondral lesion of the distal tibia with an iliac crest graft and autologous matrix-induced chondrogenesis (AMIC): a case report

Isolated osteochondral lesions (OCL) of the distal tibia are rare and lack clear treatment guidelines. With the case we present here, we suggest a novel surgical approach and report the successful use of autologous matrix-induced chondrogenesis-aided reconstruction for OCL of the distal tibia. A 29-year-old male patient complained about persisting pain of the left ankle joint and a restricted activity level 12 months after an ankle sprain. Imaging revealed edema of the subchondral bone and thinning of the cartilage above the osseous defect at the lateral distal tibia. The OCL was debrided followed by microfracturing of the underlying sclerotic bone. A cancellous bone plug was harvested from the iliac crest and impacted into the defect. A collagen matrix was then fixed on the defect. After 12 months, the patient was free of pain and returned to full activity. Conventional radiographs at 1 year showed successful osseous integration of the plug and a nearly anatomic shape of the tibial joint line. Delayed gadolinium-enhanced MRI of cartilage scans at 36 months showed an intact cartilage layer over the defect and glycosaminoglycan content, indicating hyaline-like cartilage repair. This case demonstrates autologous matrix-induced chondrogenesis-aided reconstruction of large osteochondral lesions of distal tibia to be a promising treatment method. Our aim was to describe the case of a patient with a large isolated osteochondral lesion of the distal tibia treated by a novel operative technique using cancellous bone from the iliac crest and a collagen I/III matrix.

Synthetic osteochondral grafting of ankle osteochondral lesions

BACKGROUND

The treatment of osteochondral lesions, especially those with a cystic component or those that have failed the standard arthroscopic procedures can be challenging. Synthetic grafts have several potential advantages over other second line treatments including the fact that only one operation is required and no other joint is violated.

METHOD

We report the results of the first series of synthetic grafts used in the treatment of osteochondral lesions of the ankle with a minimum of one year follow up.

RESULTS

There was significant improvement in the American Orthopaedic Foot & Ankle Society (AOFAS) Hindfoot and Ankle Osteoarthritis Scale (AOS) scores and all patients were satisfied with the results of surgery. Magnetic Resonance Imaging (MRI) scans at one year have demonstrated resolution of the bony cysts and surrounding bone marrow oedema but, worryingly, continued to show high signal on the T2 weighted images within the plugs themselves. Qualitative T2 mapping has suggested a fibrous rather than hyaline appearance of the cartilage portions of the plugs.

CONCLUSIONS

The clinical results have been encouraging but more patients and longer follow up are required before firm conclusions can be drawn.

We do not have evidence based methods for the treatment of cartilage defects in the knee

PURPOSE

The aim of this study was to perform a systematic review of studies concerning current treatment of chondral defects of the knee.

METHODS

The relevance for evidence based data and for successful surgical treatment of cartilage defects was evaluated. From 56,098 evaluated studies, 133 studies could be further pursued. These supplied data concerning microfracturing, the osteochondral autograft transplantation system (OATS), the autologous chondrocyte implantation (ACI) and the matrix induced chondrocyte implantation (MACI). The modified Coleman Methodical Score (CMS) and the Level of Evidence (LOE) were applied to evaluate the quality.

RESULTS

In these studies, a total of 6,920 patients were reviewed with a median of 32 patients per study and a mean follow-up of 24 months. The mean CMS was 58 of 100 points. No study reached 100 points in the CMS. Three studies reached a level above 90. Ten studies were Level I, five studies reached Level II. Seven studies reached Level III, 111 studies Level IV. MRI scans to verify the clinical data were used by only 72 studies. The means in the modified CMS were for the different procedures as follows: ACI 58 points, MACI 57 points, microfracturing 68 points and OATS 50 points. 24 studies applied the Lysholm Score (LS) for clinical evaluation of cartilage surgery. All operative procedures yielded comparable improvements of the LS (n.s.) meaning that no operative procedure proved superior.

CONCLUSION

As the majority of studies evaluated by this review is insufficient for EBM purposes more coherent studies with LOE of I or II are needed. Co-relating the systems of CMS and LOE and validating the applied scores seems desirable.

Current concepts in the diagnosis and treatment of osteochondral lesions of the ankle

Osteochondral lesions of the ankle are a more common source of ankle pain than previously recognized. Although the exact pathophysiology of the condition has not been clearly established, it is likely that a variety of etiological factors play a role, with trauma, typically from ankle sprains, being the most common. Technological advancements in ankle arthroscopy and radiologic imaging, most importantly magnetic resonance imaging, have improved diagnostic capabilities for detecting osteochondral lesions of the ankle. Moreover, these technologies have allowed for the development of more sophisticated classification systems that may, in due course, direct specific future treatment strategies. Nonoperative treatment yields best results when employed in select pediatric and adolescent patients with osteochondritis dissecans. However, operative treatment, which is dependent on the size and site of the lesion, as well as the presence or absence of cartilage damage, is frequently warranted in both children and adults with osteochondral lesions. Arthroscopic microdrilling, micropicking, and open procedures, such as osteochondral autograft transfer system and matrix-induced autologous chondrocyte implantation, are frequently employed. The purpose of this article is to review the history, etiology, and classification systems for osteochondral lesions of the ankle, as well as to describe current approaches to diagnosis and management.

Treatment of a distal tibial osteochondral lesion with a synthetic osteochondral plug: a case report

Level of Evidence: V, Expert Opinion

Autologous chondrocyte transplantation for the treatment of massive cartilage lesion of the distal tibia: a case report with 8-year follow-up

We report on the 8-year follow-up outcome after autologous chondrocyte transplantation in a case of massive cartilage lesion of the distal tibia in a young patient after intraarticular fracture. To our knowledge, this is the first case report in which autologous chondrocyte transplantation was performed in the distal tibial chondral lesion. Long-term clinical success was achieved by this method of treatment in a patient too young to be treated with arthrodesis.

MR imaging of osteochondral grafts and autologous chondrocyte implantation

Surgical articular cartilage repair therapies for cartilage defects such as osteochondral autograft transfer, autologous chondrocyte implantation (ACI) or matrix associated autologous chondrocyte transplantation (MACT) are becoming more common. MRI has become the method of choice for non-invasive follow-up of patients after cartilage repair surgery. It should be performed with cartilage sensitive sequences, including fat-suppressed proton density-weighted T2 fast spin-echo (PD/T2-FSE) and three-dimensional gradient-echo (3D GRE) sequences, which provide good signal-to-noise and contrast-to-noise ratios. A thorough magnetic resonance (MR)-based assessment of cartilage repair tissue includes evaluations of defect filling, the surface and structure of repair tissue, the signal intensity of repair tissue and the subchondral bone status. Furthermore, in osteochondral autografts surface congruity, osseous incorporation and the donor site should be assessed. High spatial resolution is mandatory and can be achieved either by using a surface coil with a 1.5-T scanner or with a knee coil at 3 T; it is particularly important for assessing graft morphology and integration. Moreover, MR imaging facilitates assessment of complications including periosteal hypertrophy, delamination, adhesions, surface incongruence and reactive changes such as effusions and synovitis. Ongoing developments include isotropic 3D sequences, for improved morphological analysis, and in vivo biochemical imaging such as dGEMRIC, T2 mapping and diffusion-weighted imaging, which make functional analysis of cartilage possible.

3.0 vs 1.5 T MRI in the detection of focal cartilage pathology--ROC analysis in an experimental model

OBJECTIVE

To use receiver operator characteristics (ROC) analysis for assessing the diagnostic performance of three cartilage-specific MR sequences at 1.5 and 3 T in detecting cartilage lesions created in porcine knees.

DESIGN

Eighty-four cartilage lesions were created in 27 porcine knee specimens at the patella, the medial and lateral femoral and the medial and lateral tibial cartilage. MR imaging was performed using a fat saturated spoiled gradient echo (SPGR) sequence (in plane spatial resolution/slice thickness: 0.20 x 0.39 mm2/1.5 mm) and two fat saturated proton density weighted (PDw) sequences (low spatial resolution: 0.31 x 0.47 mm2/3 mm and high spatial resolution: 0.20 x 0.26 mm2/2 mm). The images were independently analyzed by three radiologists concerning the absence or presence of lesions using a five-level confidence scale. Significances of the differences for the individual sequences were calculated based on comparisons of areas under ROC curves (A(Z)).

RESULTS

The highest A(Z)-values for all three radiologists were consistently obtained for the SPGR (A(Z) = 0.84) and the high-resolution (hr) PDw (A(Z) = 0.79) sequences at 3T. The corresponding A(Z)-values at 1.5 T were 0.77 and 0.69; the differences between 1.5 and 3 T were statistically significant (P < 0.05). A(Z)-values for the low-resolution PDw sequence were lower: 0.59 at 3 T and 0.55 at 1.5 T and the differences between 1.5 and 3T were not significant.

CONCLUSION

With optimized hr MR sequences diagnostic performance in detecting cartilage lesions was improved at 3 T. For a standard, lower spatial resolution PDw sequence no significant differences, however, were found.

Normal and pathological MR findings in osteochondral autografts with longitudinal follow-up

The purpose of this study was to analyze normal and pathological MR findings in osteochondral autograft transfer systems (OATS) of the knee and ankle in the longitudinal follow-up and in relation to the clinical findings. MR imaging was performed in 55 patients (21 females: 34 males; mean age 34.5+/-12.1 years) after OATS procedures in the knee (n=45) and ankle (n=10). MR sequences were obtained with and without intravenous Gd-DTPA administration within the first year post-operatively, in 30 patients within the second and in 13 patients in the third year. One hundred and five OATS cylinders were implanted. MR findings consistent with osteonecroses were detected in eight cylinders (n=6 in the knee and n=2 in the ankle) in six patients; four out of eight were demonstrated during the first year and four/eight in the second year. Edema around and/or in the cylinders was found in 28/55 of the patients within the first year, five/30 in the second year and in two/13 in the third year. No substantial changes in the cartilage signal intensity or the cartilage-cartilage interface were demonstrated in the longitudinal follow-up within the first three years. Clinical and MR findings were not consistently associated in particular in the patients with osteochondral autograft necroses.