Weightbearing ovine osteochondral defects heal with inadequate subchondral bone plate restoration: implications regarding osteochondral autograft harvesting

Purpose

It is unknown what causes donor site morbidity following the osteochondral autograft transfer procedure or how donor sites heal. Contact pressure and edge loading at donor sites may play a role in the healing process. It was hypothesized that an artificially created osteochondral defect in a weightbearing area of an ovine femoral condyle will cause osseous bridging of the defect from the upper edges, resulting in incomplete and irregular repair of the subchondral bone plate.

Methods

To simulate edge loading, large osteochondral defects were created in the most unfavourable weightbearing area of 24 ovine femoral condyles. After killing at 3 and 6?months, osteochondral defects were histologically and histomorphometrically evaluated with specific attention to subchondral bone healing and subchondral bone plate restoration.

Results

Osteochondral defect healing showed progressive osseous defect bridging by sclerotic circumferential bone apposition. Unfilled area decreased significantly from 3 to 6 months (P?=?0.004), whereas bone content increased (n.s.). Complete but irregular subchondral bone plate restoration occurred in ten animals. In fourteen animals, an incomplete subchondral bone plate was found. Further common findings included cavitary lesion formation, degenerative cartilage changes and cartilage and subchondral bone collapse.

Conclusions

Osteochondral defect healing starts with subchondral bone plate restoration. However, after 6 months, incomplete or irregular subchondral bone plate restoration and subsequent failure of osteochondral defect closure is common. Graft harvesting in the osteochondral autograft transfer procedure must be viewed critically, as similar changes are also present in humans.

Level of evidence

Prognostic study, Level III.     

Failed cartilage repair for early osteoarthritis defects: a biochemical, histological and immunohistochemical analysis of the repair tissue after treatment with marrow-stimulation techniques

Purpose

To examine the entire repair tissue resulting from marrow-stimulation techniques in patients with early osteoarthritis.

Methods

The repair tissue and adjacent articular cartilage after failed marrow-stimulation techniques (microfracture and Pridie drilling) of 5 patients (47–65 years old) with cartilage defects and radiographic early osteoarthritis (Kellgren–Lawrence grading 1 and 2) was removed during total joint arthroplasty (mean time until analysis: 8.8 months), analysed by histology, polarized light microscopy, immunohistochemistry, biochemistry and by histological score systems.

Results

Macroscopic cartilage repair assessment revealed ICRS grades of II (nearly normal) and III (abnormal). Cartilage defects were mostly completely filled with a fibrocartilaginous tissue that had small and large fissures. Cartilage-specific stains of the repair tissue were more intense than the surrounding native cartilage but reduced compared with normal articular cartilage. The subchondral bone was incompletely restored. A new tidemark was absent. The repair tissue always showed positive immunoreactivity for types II and X collagen, and was sometimes positive for type I collagen. Proteoglycan contents of the repair tissue were generally higher than of the surrounding cartilage. The repair tissue was always more cellular than the adjacent articular cartilage. Histological scoring of the repair tissue revealed a mean Sellers score of 17.6 ± 3.0 and an ICRS grading of 7–9.

Conclusion

Failed marrow stimulation of articular cartilage defects in patients with early osteoarthritis is characterized by fibrocartilaginous repair. The balance of cell number to extracellular matrix is shifted towards an increased cell number in this tissue. Articular cartilage repair did not reach the quality of normal hyaline articular cartilage.

Level of evidence

IV.     

Treatment of isolated chondral and osteochondral defects in the knee by autologous matrix-induced chondrogenesis (AMIC)

Purpose

The purpose of this study is to evaluate clinical and radiological outcomes of patients treated with autologous matrix-induced chondrogenesis (AMIC) for full-thickness chondral and osteochondral defects of the femoral condyles and patella.

Method

A retrospective evaluation of clinical and radiographic outcomes of patients treated with AMIC for chondral and osteochondral full-thickness cartilage defects of the knee was performed with a mean follow-up of 28.8 ± 1.5 months (range, 13–51 months).

Results

Significant improvements in clinical outcome scores (IKDC, Lysholm, Tegner, and VAS pain score) were noted. The largest improvements were seen in the osteochondral subgroup (mean age 25.9 years), whereas patients treated for chondral defects in the patellofemoral joint and on the femoral condyles improved less. Patients in all groups were generally satisfied with their results. MRI evaluation showed that tissue filling was present but generally not complete or homogenous.

Conclusions

AMIC is a safe procedure and leads to clinical improvement of symptomatic full-thickness chondral and osteochondral defects and to regenerative defect filling. The value of AMIC relative to other cartilage repair procedures and to the natural course remains undefined.

Level of evidence

Case series, Level IV.     

Transplanted articular chondrocytes co-overexpressing IGF-I and FGF-2 stimulate cartilage repair in vivo

Purpose

The combination of chondrogenic factors might be necessary to adequately stimulate articular cartilage repair. In previous studies, enhanced repair was observed following transplantation of chondrocytes overexpressing human insulin-like growth factor I (IGF-I) or fibroblast growth factor 2 (FGF-2). Here, the hypothesis that co-overexpression of IGF-I and FGF-2 by transplanted articular chondrocytes enhances the early repair of cartilage defects in vivo and protects the neighbouring cartilage from degeneration was tested.

Methods

Lapine articular chondrocytes were transfected with expression plasmid vectors containing the cDNA for the Escherichia coli lacZ gene or co-transfected with the IGF-I and FGF-2 gene, encapsulated in alginate and transplanted into osteochondral defects in the knee joints of rabbits in vivo.

Results

After 3 weeks, co-overexpression of IGF-I/FGF-2 improved the macroscopic aspect of defects without affecting the synovial membrane. Immunoreactivity to type-I collagen, an indicator of fibrocartilage, was significantly lower in defects receiving IGF-I/FGF-2 implants. Importantly, combined IGF-I/FGF-2 overexpression significantly improved the histological repair score. Most remarkably, such enhanced cartilage repair was correlated with a 2.1-fold higher proteoglycan content of the repair tissue. Finally, there were less degenerative changes in the cartilage adjacent to the defects treated with IGF-I/FGF-2 implants.

Conclusion

The data demonstrate that combined gene delivery of therapeutic growth factors to cartilage defects may have value to promote cartilage repair. The results also suggest a protective effect of IGF-I/FGF-2 co-overexpression on the neighbouring articular cartilage. These findings support the concept of implementing gene transfer strategies for articular cartilage repair in a clinical setting.     

The combination of microfracture and a cell-free polymer-based implant immersed with autologous serum for cartilage defect coverage

Purpose

The purpose of this short-term pilot study was to determine the clinical and MRI outcome of a combination of microfracture with a cell-free polymer-based matrix for the treatment of cartilage defects in the knee.

Methods

The technique was used for treatment of symptomatic cartilage defects in the knee. Five patients were prospectively evaluated during 2?years with use of the Knee injury and Osteoarthritis Outcome Score (KOOS), the Tegner activity scale and the visual analog scale (VAS). MRI data were analyzed based on the original and modified MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) scoring system at 6, 12 and 24?months of follow-up.

Results

A gradual clinical improvement was observed during the follow-up. Adverse reactions to the matrix were not observed. The scaffold was firmly fixed with the use of bioresorbable pins. Both MOCART scoring systems revealed no significant deterioration or improvement in the repair tissue during the follow-up period. However, the majority of the patients exhibited subchondral lamina and bone changes. The formation of an intralesional osteophyte was observed in one case.

Conclusions

The key finding in this study was that this procedure is safe for the treatment of cartilage defects in the knee. The patients showed a gradual clinical improvement postoperatively. Sixty percent (3/5) of the defects were adequately (complete or hypertrophic) filled with repair tissue at 2?years of follow-up.

Level of evidence

IV.     

Cartilage repair using mesenchymal stem cell (MSC) sheet and MSCs-loaded bilayer PLGA scaffold in a rabbit model

Purpose

The integration of regenerated cartilage with surrounding native cartilage is a major challenge for the success of cartilage tissue-engineering strategies. The purpose of this study is to investigate whether incorporation of the power of mesenchymal stem cell (MSC) sheet to MSCs-loaded bilayer poly-(lactic-co-glycolic acid) (PLGA) scaffolds can improve the integration and repair of cartilage defects in a rabbit model.

Methods

Rabbit bone marrow-derived MSCs were cultured and formed cell sheet. Full-thickness cylindrical osteochondral defects (4 mm in diameter, 3 mm in depth) were created in the patellar groove of 18 New Zealand white rabbits and the osteochondral defects were treated with PLGA scaffold (n = 6), PLGA/MSCs (n = 6) or MSC sheet-encapsulated PLGA/MSCs (n = 6). After 6 and 12 weeks, the integration and tissue response were evaluated histologically.

Results

The MSC sheet-encapsulated PLGA/MCSs group showed significantly more amounts of hyaline cartilage and higher histological scores than PLGA/MSCs group and PLGA group (P < 0.05). In addition, the MSC sheet-encapsulated PLGA/MCSs group showed the best integration between the repaired cartilage and surrounding normal cartilage and subchondral bone compared to other two groups.

Conclusions

The novel method of incorporation of MSC sheet to PLGA/MCSs could enhance the ability of cartilage regeneration and integration between repair cartilage and the surrounding cartilage. Transplantation of autologous MSC sheet combined with traditional strategies or cartilage debris might provide therapeutic opportunities for improving cartilage regeneration and integration in humans.     

Cartilage repair in the knee with subchondral drilling augmented with a platelet-rich plasma-immersed polymer-based implant

Purpose

The aim of our study was to analyse the clinical and histological outcome after the treatment of focal cartilage defects in non-degenerative and degenerative knees with bone marrow stimulation and subsequent covering with a cell-free resorbable polyglycolic acid–hyaluronan (PGA-HA) implant immersed with autologous platelet-rich plasma (PRP).

Methods

Fifty-two patients (mean age 44 years) with focal chondral defects in radiologically confirmed non-degenerative or degenerative knees were subjected to subchondral drilling arthroscopically. Subsequently, defects were covered with the PGA-HA implant immersed with autologous PRP. At 2-year follow-up, the patients’ situation was assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and compared to the pre-operative situation and 3–12-month follow-up. Biopsies (n = 4) were harvested at 18–24 months after implantation and were analysed by histology and collagen type II immune staining.

Results

At 1- and 2-year follow-up, the KOOS showed clinically meaningful and significant (p < 0.05) improvement in all subcategories compared to baseline and to 3-month follow-up. There were no differences in KOOS data obtained after 2 years compared to 1 year after the treatment. Histological analysis of the biopsy tissue showed hyaline-like to hyaline cartilage repair tissue that was rich in cells with a chondrocyte morphology, proteoglycans and type II collagen.

Conclusions

Covering of focal cartilage defects with the PGA-HA implant and PRP after bone marrow stimulation improves the patients’ situation and has the potential to regenerate hyaline-like cartilage.

Level of evidence

Case series, Level IV.     

Transarticular drilling for stable juvenile osteochondritis dissecans of the medial femoral condyle

Purpose

Drilling is the most common operative treatment for stable juvenile osteochondritis dissecans (OCD) of the knee. However, prognostic factors remain unclear because of lack of precise radiographic and histopathologic investigations. The purpose of this study was to evaluate the clinical results and prognostic factor of the arthroscopic drilling for juvenile OCD lesions at the medial femoral condyle (MFC), using computed tomography (CT) images.

Methods

Eighteen skeletally immature patients (boys, n?=?16; girls, n?=?2, mean age, 12?years) underwent arthroscopic antegrade transarticular drilling for a total of 19 OCD lesions of MFC. Functional outcomes were evaluated with the Lysholm score at follow-up (mean, 30?months). Preoperative osteochondral condition and postoperative healing were evaluated by CT images.

Results

All 18 patients returned to their previous level of sports activity and showed excellent functional outcomes (mean Lysholm score, 77.2?±?9.4 preoperative vs. 99.5?±?1.6 postoperative). There were 10 osteochondral lesions and 9 subchondral bone defect lesions under preoperative CT examination. Postoperatively, 15 of 19 lesions healed completely at a mean of 6?months; however, the remaining four lesions (all osteochondral types) did not achieve complete radiographic healing after 2?years.

Conclusion

Transarticular drilling for stable juvenile OCD produced excellent functional outcomes. However, the osteochondral type may influence radiographic outcome.

Level of evidence

Case series, Level IV.     

The effects of defect size, orientation, and location on subchondral bone contact in oval-shaped experimental articular cartilage defects in a bovine knee model

Purpose

Chondral defects of the knee may lead to pain and disability, often requiring surgical intervention. The purpose of this study was to identify how size, location, and orientation influences subchondral bone contact within oval-shaped chondral defects.

Methods

Full-thickness defects were created in twelve bovine knees. Defect orientation was randomized between coronal and sagittal planes on both the medial and lateral femoral condyles (MFC and LFC). In extension, knees were statically loaded to 1,000 N. Area measurements were recorded using Tekscan sensors and I-Scan software. A MATLAB program computed defect area and the area within the defect demonstrating subchondral bone contact.

Results

Defect area, location, and orientation each had a significant effect on subchondral bone contact (p < 0.001), and significant interactions were found between defect area and both location and orientation. The size threshold (cm²) at which significant contact occurred on the subchondral bone within the defect was smallest for LFC/coronal defects (0.73 cm²), then LFC/sagittal (1.14 cm²), then MFC/coronal (1.61 cm²), and then MFC/sagittal (no threshold reached).

Conclusions

Intra-articular location and orientation of a femoral condyle chondral defect, in addition to area, significantly influence femoral subchondral bone contact within the defect and the threshold at which subchondral bone contact occurs within the defect. The parameters of defect location and shape orientation supplement current surgical algorithms to manage knee articular cartilage surgery. This may indicate different cartilage restorative procedures based on the effect on the subchondral bone from the defect geometry itself and the selected cartilage surgery.     

One-step osteochondral repair with cartilage fragments in a composite scaffold

Purpose

This study proposes a single-step therapeutic approach for osteochondral defects using autologous cartilage fragments loaded onto a scaffold composed of a hyaluronic acid (HA) derivative, human fibrin glue (FG) and autologous platelet-rich-plasma (PRP), in a rabbit model. The aim is to demonstrate the in vitro outgrowth of chondrocytes from cartilage fragments and the in vivo formation of a functional repair tissue.

Methods

In vitro: minced articular cartilage was loaded onto two different types of scaffold (paste or membrane) according to two different HA preparations (injectable HA-derivative or HA-derivative felt). In vivo: trochlear osteochondral defects were created in 50 adult rabbits, which were then assigned to 5 different treatment groups: cartilage fragments loaded onto membrane scaffolds with FG (Group 1) or without FG (Group 2); membrane scaffolds alone with FG (Group 3) or without FG (Group 4); empty defects (Group 5). Membrane scaffolds were used “in vivo” for simpler preparation and better adhesive properties. Repair processes were evaluated histologically and by immunohistochemistry at 1, 3, and 6 months.

Results

An in vitro time-dependent cell outgrowth from cartilage fragments was observed with both types of scaffolds. At 6 months, in vivo, cartilage fragment-loaded scaffolds induced significantly better repair tissue than the scaffold alone using histological scoring. Repair in Group 2 was superior to that in any of the control groups (p < 0.05).

Conclusion

Autologous cartilage fragments loaded onto an HA felt/FG/PRP-scaffold provided an efficient cell source, and allowed for an improvement of the repair process of ostechondral defects in a rabbit model. Human FG, however, hampered the rabbit healing process. These results may have clinical relevance as they show the potential of a novel one-stage repair technique for osteochondral defects.     

Trends in the surgical treatment of articular cartilage defects of the knee in the United States

Purpose

The purpose of this study was to evaluate trends in surgical treatment of articular cartilage defects of the knee in the United States.

Methods

The current procedural terminology (CPT) billing codes of patients undergoing articular cartilage procedures of the knee were searched using the PearlDiver Patient Record Database, a national database of insurance billing records. The CPT codes for chondroplasty, microfracture, osteochondral autograft, osteochondral allograft, and autologous chondrocyte implantation (ACI) were searched.

Results

A total of 163,448 articular cartilage procedures of the knee were identified over a 6-year period. Microfracture and chondroplasty accounted for over 98 % of cases. There was no significant change in the incidence of cartilage procedures noted from 2004 (1.27 cases per 10,000 patients) to 2009 (1.53 cases per 10,000 patients) (p = 0.06). All procedures were performed more commonly in males (p < 0.001). This gender difference was smallest in patients undergoing chondroplasty (51 % males and 49 % females) and greatest for open osteochondral allograft (61 % males and 39 % females). Chondroplasty and microfracture were most commonly performed in patients aged 40–59, while all other procedures were performed most frequently in patients <40 years old (p < 0.001).

Conclusions

Articular cartilage lesions of the knee are most commonly treated with microfracture or chondroplasty in the United States. Chondroplasty and microfracture were most often performed in middle-aged patients, whereas osteochondral autograft, allograft, and ACI were performed in younger patients, and more frequently in males.

Level of evidence

Cross-sectional study, Level IV.     

Bony periosteum-covered iliac crest plug transplantation for severe osteochondral lesions of the talus: a modified mosaicplasty procedure

Purpose

This study reports first evidence of a modified procedure for osteochondral autologous transplantation where bony periosteum-covered plugs are harvested at the iliac crest and transplanted into the talar osteochondral lesion.

Methods

Thirteen out of 14 patients, average age 39.6 (SD 14.4) years, were followed clinically and radiographically for a median of 25 (24–28) months (minimal follow-up, 24 months).

Results

For these 13 patients, the American Orthopaedic Foot and Ankle Society hindfoot score increased from 47 (SD 11) points pre-operatively, to 81 (SD 14) points postoperatively (p < 0.0001). The average pain score decreased from 6.6 (SD 1.3) points pre-operatively, to 1.4 (SD 1.9) points postoperatively (p < 0.0001). Seven patients returned to sports activity. Radiographically good plug osteointegration was observed in nine out of 11 ankles. Follow-up arthroscopy showed fibrous cartilage in four ankles, periosteum hypertrophy in five ankles, and partial or total missing of coverage of the bone in three ankles. Three revision surgeries had to be performed.

Conclusions

This modified mosaicplasty might be recommended for severe and recurrent osteochondral lesions of the talus and may lead to restoration of the subchondral bone stock, formation of fibro-cartilage, and stable joint function.

Level of evidence

IV.     

Mesenchymal stem cells for the treatment of cartilage lesions: from preclinical findings to clinical application in orthopaedics

Purpose

The aim of this systematic review is to examine the available clinical evidence in the literature to support mesenchymal stem cell (MSC) treatment strategies in orthopaedics for cartilage defect regeneration.

Methods

The research was performed on the PubMed database considering the English literature from 2002 and using the following key words: cartilage, cartilage repair, mesenchymal stem cells, MSCs, bone marrow concentrate (BMC), bone marrow-derived mesenchymal stem cells, bone marrow stromal cells, adipose-derived mesenchymal stem cells, and synovial-derived mesenchymal stem cells.

Results

The systematic research showed an increasing number of published studies on this topic over time and identified 72 preclinical papers and 18 clinical trials. Among the 18 clinical trials identified focusing on cartilage regeneration, none were randomized, five were comparative, six were case series, and seven were case reports; two concerned the use of adipose-derived MSCs, five the use of BMC, and 11 the use of bone marrow-derived MSCs, with preliminary interesting findings ranging from focal chondral defects to articular osteoarthritis degeneration.

Conclusions

Despite the growing interest in this biological approach for cartilage regeneration, knowledge on this topic is still preliminary, as shown by the prevalence of preclinical studies and the presence of low-quality clinical studies. Many aspects have to be optimized, and randomized controlled trials are needed to support the potential of this biological treatment for cartilage repair and to evaluate advantages and disadvantages with respect to the available treatments.

Level of evidence

IV.     

A multilayer biomaterial for osteochondral regeneration shows superiority vs microfractures for the treatment of osteochondral lesions in a multicentre randomized trial at 2 years

Purpose

The increasing awareness on the role of subchondral bone in the etiopathology of articular surface lesions led to the development of osteochondral scaffolds. While safety and promising results have been suggested, there are no trials proving the real potential of the osteochondral regenerative approach. Aim was to assess the benefit provided by a nanostructured collagen–hydroxyapatite (coll-HA) multilayer scaffold for the treatment of chondral and osteochondral knee lesions.

Methods

In this multicentre randomized controlled clinical trial, 100 patients affected by symptomatic chondral and osteochondral lesions were treated and evaluated for up to 2 years (51 study group and 49 control group). A biomimetic coll-HA scaffold was studied, and bone marrow stimulation (BMS) was used as reference intervention. Primary efficacy measurement was IKDC subjective score at 2 years. Secondary efficacy measurements were: KOOS, IKDC Knee Examination Form, Tegner and VAS Pain scores evaluated at 6, 12 and 24 months. Tissue regeneration was evaluated with MRI MOCART scoring system at 6, 12 and 24 months. An external independent agency was involved to ensure data correctness and objectiveness.

Results

A statistically significant improvement of all clinical scores was obtained from basal evaluation to 2-year follow-up in both groups, although no overall statistically significant differences were detected between the two treatments. Conversely, the subgroup of patients affected by deep osteochondral lesions (i.e. Outerbridge grade IV and OCD) showed a statistically significant better IKDC subjective outcome (+12.4 points, p = 0.036) in the coll-HA group. Statistically significant better results were also found for another challenging group: sport active patients (+16.0, p = 0.027). Severe adverse events related to treatment were documented only in three patients in the coll-HA group and in one in the BMS group. The MOCART score showed no statistical difference between the two groups.

Conclusions

This study highlighted the safety and potential of a biomimetic implant. While no statistically significant differences were found compared to BMS for chondral lesions, this procedure can be considered a suitable option for the treatment of osteochondral lesions.

Level of evidence

I.

     

Treatment of osteochondral defects of the talus in children

Purpose

Osteochondral talar defects are infrequent in children, and little is known about the treatment and clinical outcome of these defects. The purpose of this study was to evaluate the clinical and radiographic outcomes of conservative and primary surgically treated osteochondral talar defects in skeletally immature children.

Methods

Thirty-six (97 %) of 37 eligible patients with a symptomatic primary osteochondral talar defect were evaluated after a median follow-up of 4 years (range 1–12 years). Clinical assessment included the Berndt and Harty outcome question, Ogilvie-Harris score, Visual Analog Scale pain score (at rest, during walking and during running), the American Orthopaedic Foot and Ankle Society (AOFAS) score, and the SF-36. Weight-bearing radiographs were compared with preoperative radiographs with the use of an ankle osteoarthritis classification system.

Results

Ninety-two per cent of the initially conservatively treated children [mean age 13 years (SD 2)] were eventually scheduled to undergo surgery. After fixation of the fragment, seven cases (78 %) reported a good Berndt and Harty outcome, and two cases (22 %) a fair outcome; the median AOFAS score was 95.0 (range 77–100). After debridement and bone marrow stimulation, 13 cases (62 %) reported a good Berndt and Harty outcome, three cases (14 %) a fair outcome, and five cases (24 %) a poor outcome; the median AOFAS score was 95.0 (range 45–100). No signs of degenerative changes were seen in both groups at follow-up.

Conclusions

Fixation and debridement and bone marrow stimulation of an osteochondral talar defect are both good surgical options after failed conservative treatment.

Level of evidence

Retrospective case series, Therapeutic, Level IV.     

Use of innovative biomimetic scaffold in the treatment for large osteochondral lesions of the knee

Purpose

Large osteochondral defects involve two different tissues characterized by different intrinsic healing capacity. Different techniques have been proposed to treat these lesions with results still under discussion. The aim of the study is to evaluate the clinical outcome of 19 patients treated with a type I collagen–hydroxyapatite nanostructural biomimetic osteochondral scaffold at minimum follow-up of 2 years.

Methods

Twenty lesions, 19 patients were treated with this scaffold implantation. The lesions size went from 4 to 8 cm² (mean size 5.2 ± 1.6 cm²). All patients were clinically evaluated using the International Repair Cartilage Society score, the Tegner Score and EQ-VAS. MRI was performed at 12 and 24 months after surgery and then every 12 months and evaluated with magnetic resonance observation of cartilage repair tissue scoring scale.

Results

The IKDC subjective score improved from a mean score of 35.7 ± 6.3 at the baseline evaluation to 67.7 ± 13.4 at 12-month follow-up (p < 0.0005). A further improvement was documented from 12 to 24 months (mean score of 72.9 ± 12.4 at 24 months) (p < 0.0005). The IKDC objective score confirmed the results. The Tegner activity score improvement was statistically significant (p < 0.0005). The EQ-VAS showed a significant improvement from 3.15 ± 1.09 to 7.35 ± 1.14 (p < 0.0005) at 2-year follow-up. The lesion’ site seems to influence the results showing a better outcome in the patients affected in the medial femoral condyle.

Conclusions

The use of the MaioRegen scaffold is a good procedure for the treatment for large osteochondral defects where other classic techniques are difficult to apply. It is an open one-step surgery with promising stable results at medium follow-up.

Level of evidence

IV.     

Use of cell-free collagen type I matrix implants for the treatment of small cartilage defects in the knee: clinical and magnetic resonance imaging evaluation

Purpose

Articular cartilage defects of the knee are a common condition for which several repair techniques have been described. The aim of the present study was to assess medium-term results of a one-step procedure using a cell-free collagen type I matrix.

Methods

Fifteen patients with articular cartilage defects of the knee were treated with an 11-mm-diameter cell-free collagen type 1 matrix implant. The matrices were implanted in a press-fit manner into the defect after careful debridement down to the subchondral bone but without penetration of this margin. Follow-up examinations were carried out at 6 weeks, 6 months, and at 12, 24, 36, and 48 months after implantation. Clinical assessment included the visual analogue scale (VAS), the Tegner activity scale, and the International Knee Documentation Committee (IKDC) score. Radiological assessment for graft attachment and tissue regeneration was performed using the magnetic observation of cartilage repair tissue (MOCART) score.

Results

A total of 15 patients (males: n = 6 and females: n = 9) with a mean age of 26.4 years (range 19–40) were treated. The mean VAS improved significantly when compared to the preoperative values (P < 0.05). Six weeks after implantation, IKDC values were slightly lower than the preoperative values (n.s.), but increased significantly at final follow-up (P < 0.05). At 24 months, there were no significant differences in the median Tegner score between the post-operative values and the preoperative values (n.s.). However, after 36 months, a significant improvement was noted that lasted at least up to 48 months (P < 0.05). The MOCART score improved consistently up to 4 years after implantation, with significant improvements already observed after 12 months (P < 0.05). No correlation between the clinical scores and the MOCART score could be perceived.

Conclusion

The present study showed that the use of cell-free collagen type I matrix implants led to a significant and durable improvement in all the clinical and imaging scores investigated 4 years after implantation.

Level of evidence

IV.     

Radiologische Bildgebung der Kniegelenkarthrose

Clinical/methodical issue

Osteoarthritis is the most common degenerative age-related joint disease leading to typical degradation of articular cartilage with severe pain and limitation of joint motion.

Standard radiological methods

Although knee radiographs are widely considered as the gold standard for the assessment of knee osteoarthritis in clinical and scientific settings they increasingly have significant limitations in situations when resolution and assessment of cartilage is required.

Methodical innovations

Analysis of osteoarthritis of the knee with conventional x-ray is associated with many technical limitations and is increasingly being replaced by high-quality assessment using magnetic resonance imaging (MRI) or sonography both in the clinical routine and scientific studies.

Performance

Novel imaging modalities such as MRI or ultrasound enable in vivo visualization of the quality of the cartilaginous structure and bone as well as all articular and periarticular tissue. Therefore, the limitations of radiographs in assessment of knee osteoarthritis could be overcome by these techniques. This review article aims to provide insights into the most important radiological features of knee osteoarthritis and systematic visualization with different imaging approaches.

Practical recommendations

The demographic development in western industrialized countries predicts an increase of ageing-related osteoarthritis of the knee for the next decades. A systematic radiological evaluation of patients with knee osteoarthritis includes the assessment of the periarticular soft tissue, cartilaginous thickness, cartilage volume, possible cartilage defects, the macromodular network of hyaline cartilage, bone marrow edema, menisci and articular ligaments. Modern imaging modalities, such as MRI and sonography allow the limitations of conventional radiography to be overcome and to visualize the knee structures in great detail to quantitatively assess the severity of knee osteoarthritis.     

Comparison of clinical outcomes between arthroscopic subchondral drilling and microfracture for osteochondral lesions of the talus

Purpose

The objectives of this study were to compare the clinical outcomes of the two common bone marrow stimulation techniques such as subchondral drilling and microfracture for symptomatic osteochondral lesions of the talus and to evaluate prognostic factors affecting the outcomes.

Methods

Ninety patients (90 ankles) who underwent arthroscopic bone marrow stimulation for small- to mid-sized osteochondral lesions of the talus constituted the study cohort. The 90 ankles were divided into two groups: a drilling group (40 ankles) and a microfracture group (50 ankles). Each group was matched for age and gender, and both groups had characteristics similar to those obtained from pre-operative demographic data. The American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score and the ankle activity score (AAS) were used to compare clinical outcomes, during a mean follow-up period of 43 months.

Results

The median AOFAS scores were 66.0 points (51–80) in drilling group and 66.5 points (45–81) in microfracture group pre-operatively, and these improved to 89.4 points (77–100) and 90.1 points (69–100) at the final follow-up, respectively. The median VAS scores improved at the final follow-up compared with the pre-operative condition. The median AAS for the drilling group improved from 4.5 (1–6) pre-operatively to 6.0 (1–8) at the final follow-up, while those for the microfracture group improved from 3.0 (2–8) to 6.0 (3–9). No significant differences were observed between the two groups in terms of the AOFAS scores, VAS, and AAS.

Conclusions

The arthroscopic subchondral drilling and microfracture techniques that were used to stimulate bone marrow showed similar clinical outcomes. The results of this study suggest that both techniques are effective and reliable in treating small- to mid-sized osteochondral lesions of the talus, regardless of which of the two techniques is used.

Level of evidence

Level III, retrospective comparative study.

     

The relationship between patellofemoral and tibiofemoral morphology and gait biomechanics following arthroscopic partial medial meniscectomy

Purpose

To examine the relationship between tibiofemoral and patellofemoral joint articular cartilage and subchondral bone in the medial and gait biomechanics following partial medial meniscectomy.

Methods

For this cross-sectional study, 122 patients aged 30–55 years, without evidence of knee osteoarthritis at arthroscopic partial medial meniscectomy, underwent gait analysis and MRI on the operated knee once for each sub-cohort of 3 months, 2 years, or 4 years post-surgery. Cartilage volume, cartilage defects, and bone size were assessed from the MRI using validated methods. The 1st peak in the knee adduction moment, knee adduction moment impulse, 1st peak in the knee flexion moment, knee extension range of motion, and the heel strike transient from the vertical ground reaction force trace were identified from the gait data.

Results

Increased knee stance phase range of motion was associated with decreased patella cartilage volume (B = ?17.9 (95 % CI ?35.4, ?0.4) p = 0.045) while knee adduction moment impulse was associated with increased medial tibial plateau area (B = 7.7 (95 % CI 0.9, 13.3) p = 0.025). A number of other variables approached significance.

Conclusions

Knee joint biomechanics exhibited by persons who had undergone arthroscopic partial meniscectomy gait may go some way to explaining the morphological degeneration observed at the patellofemoral and tibiofemoral compartments of the knee as patients progress from surgery.

Level of evidence

III.