A prospective randomized clinical study of mosaic osteochondral autologous transplantation versus microfracture for the treatment of osteochondral defects in the knee joint in young athletes

Cell-based tissue engineering strategies used in the clinical repair of articular cartilage

One of the most important issues facing cartilage tissue engineering is the inability to move technologies into the clinic. Despite the multitude of current research in the field, it is known that 90% of new drugs that advance past animal studies fail clinical trials. The objective of this review is to provide readers with an understanding of the scientific details of tissue engineered cartilage products that have demonstrated a certain level of efficacy in humans, so that newer technologies may be developed upon this foundation. Compared to existing treatments, such as microfracture or autologous chondrocyte implantation, a tissue engineered product can potentially provide more consistent clinical results in forming hyaline repair tissue and in filling the entirety of the defect. The various tissue engineering strategies (e.g., cell expansion, scaffold material, media formulations, biomimetic stimuli, etc.) used in forming these products, as collected from published literature, company websites, and relevant patents, are critically discussed. The authors note that many details about these products remain proprietary, not all information is made public, and that advancements to the products are continuously made. Nevertheless, by understanding the design and production processes of these emerging technologies, one can gain tremendous insight into how to best use them and also how to design the next generation of tissue engineered cartilage products.

Management of knee articular cartilage injuries in athletes: chondroprotection, chondrofacilitation, and resurfacing

Articular cartilage defects of the knee are common among athletes where the physical demands of sport result in significant stresses on joints. Chondral defects are associated with pain and functional impairment that limit sporting participation and may progress to joint degeneration and frank arthritis. Management of established chondral lesions aims to allow athletes to return to high-impact sports and can be considered in terms of protection of existing cartilage, chondrofacilitation, and resurfacing. Repaired and regenerated cartilage must closely resemble and function like normal hyaline cartilage, and this ability may be the most significant factor for the return to sport. Based on our experiences and the available literature, we outline how athletes can best protect their cartilage, how physicians can facilitate intrinsic repair of established lesions, and which methods of cartilage restoration or resurfacing should be used in different situations.

LEVEL OF EVIDENCE

IV.

Influencing chondrogenic differentiation of human mesenchymal stromal cells in scaffolds displaying a structural gradient in pore size

Articular cartilage lesions have a limited ability to heal by themselves. Yet, golden standard treatments for cartilage repair such as drilling, microfracture and mosaicplasty provide further damage and an unstable solution that degenerates into fibrocartilage in time. Articular cartilage presents a number of gradients in cell number and size along with structural gradients in extra cellular matrix (ECM) composition. Therefore, creating scaffolds that display a structural gradient can be an appealing strategy for cartilage tissue regeneration treatments. In the present study, a scaffold with an in-built discrete gradient in pore size was produced by additive manufacturing. Human mesenchymal stromal cells (hMSCs) were seeded within the gradient scaffolds and their proliferation, differentiation and ECM deposition was evaluated with respect to 2 non-gradient scaffolds. Glycosaminoglycan (GAG) deposition was significantly higher in gradient scaffolds and non-gradient scaffolds with the smallest pore size compared to non-gradient scaffolds with the largest pore size. A gradual increase of chondrogenic markers was observed within the gradient structures with decreasing pore size, which was also accompanied by an increasingly compact ECM formation. Therefore, scaffolds displaying a structural gradient in pore size seem to be a promising strategy to aid in the process of hMSC chondrogenic differentiation and could be considered for improved cartilage tissue regeneration applications.

STATEMENT OF SIGNIFICANCE

We present the development of a novel hierarchical scaffold obtained by additive manufacturing. Structural hierarchy is obtained by changing pore size within the pore network characterizing the fabricated scaffolds and proves to be a functional element in the scaffold to influence adult stem cell differentiation in the chondrogenic lineage. Specifically, in regions of the scaffolds presenting smaller pores an increasing differentiation of stem cells toward the chondrogenic differentiation is displayed. Taking inspiration from the zonal organization of articular cartilage tissue, pore size gradients could, therefore, be considered as a new and important element in designing 3D scaffolds for regenerative medicine applications, in particular for all those tissues where gradient physical properties are present.

Knee Donor Site Morbidity Following Harvest of Medial Femoral Trochlea Osteochondral Flaps for Carpal Reconstruction

PURPOSE

This study examines donor site morbidity associated with the medial femoral trochlea (MFT) when used as a donor site for vascularized osteochondral flaps for reconstruction of challenging carpal defects such as proximal pole scaphoid nonunion and advanced Kienböck disease.

METHODS

The retrospective study population included all patients who had undergone MFT flap harvest for scaphoid or lunate reconstruction. Chart review, patient questionnaires, and validated knee function assessment tools were used: International Knee Documentation Committee Subjective Knee Form scores ranged from 0 (maximal disability) to 100 (no disability). Western Ontario and McMaster Universities osteoarthritis index scores ranged from 0% (no disability) to 100% (maximal disability). Magnetic resonance imaging and radiographs were obtained on the donor knee on the majority of patients.

RESULTS

Questionnaire response rate was 79% (45 of 57 patients). Average patient age was 35 ± 11 years (range, 19-70 years). Average postoperative follow-up was 27 ± 17 months (range, 9-108 months). The indication for MFT flap reconstruction was scaphoid nonunion in 30 patients and Kienböck disease in 15 patients. All 45 patients had a stable knee on examination. Magnetic resonance and radiographic imaging obtained on 35 patients exhibited no pathological changes. Average duration of postoperative pain was 56 ± 59 days (range, 0-360 days); average duration until patients reported the knee returning to normal was 90 ± 60 days (range, 14-360 days). Forty-three of 44 patients would have the same surgery again if needed; overall satisfaction with the surgery was rated as 5 ± 1 (range, 2-5) on a scale from 0 (no satisfaction) to 5 (maximal satisfaction). Average International Knee Documentation Committee score was 96 ± 9 (range, 56.3-100) and the average Western Ontario and McMaster Universities score was 6% ± 16% (range, 0%-68%).

CONCLUSIONS

Medial femoral trochlea osteochondral flap harvest results in minimal donor site morbidity in the majority of patients. Symptoms are time limited. Intermediate-term follow-up demonstrates excellent results in subjective outcome measures.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Can young and active patients participate in sports after osteochondral autologous transfer combined with valgus high tibial osteotomy?

PURPOSE

To evaluate sporting activity following osteochondral autologous transfer (OAT) combined with valgus high tibial osteotomy (HTO) in young and active patients with focal osteochondral defects of the medial femoral condyle and concomitant varus malalignment.

METHODS

Thirty patients with focal osteochondral defects of the medial femoral condyle and varus malalignment >2° were enrolled. All patients were active in sports on a regular base prior to surgery (lifetime), but were unable to perform sports at the time of surgery. Sporting activity 1 year preoperatively and at final follow-up was compared using a previously published sports questionnaire, which assesses sports level, number of sports disciplines, sports frequency, sports duration and the participation in 32 common sports disciplines. Additionally, the Tegner activity scale and the Activity Rating Scale were used.

RESULTS

After a mean follow-up of 6.9 years (2.5-9.8; SD 2.4), 76.7 % of patients were participating in sports on a regular basis (Fig. 2). Compared to 1 year preoperatively, there was no difference (n.s.) with regard to sports, the number of sports disciplines, sports frequency and sports duration (Fig. 4). The median Tegner activity scale measured preoperatively 5.0 (2.0-7.0) and post-operatively 5.0 (4.0-7.0) points (Fig. 3), and the ARS changed from 5.7 to 5.3 points (n.s.). The different types of sports disciplines were comparable between 1 year preoperatively and at follow-up.

CONCLUSION

A high return to sports rate and an activity level comparable to the state at 1 year preoperatively can be expected in young and active patients after combined OAT and valgus HTO. This seems to be relevant in clinical practice when planning, indicating and performing these complex procedures.

LEVEL OF EVIDENCE

IV.

Symptoms and function in patients with articular cartilage lesions in 1,000 knee arthroscopies

PURPOSE

Focal chondral lesions of the knee are commonly occurring. A lot is known about their frequency, size and localisation in arthroscopic series, but less about the symptoms they elicit and little about how the arthroscopic findings and symptoms correlate. The purposes of the present study included to investigate the relationship between articular cartilage lesion factors and patient factors, and to compare the symptoms and function of cartilage lesion patients to those of patients with a deficient ACL.

METHODS

A prospective registration was conducted of preoperative data including Lysholm knee score and perioperative findings in 1,000 consecutive patients undergoing an arthroscopic procedure of the knee-including microfracture of articular cartilage defects and ACL reconstructions.

RESULTS

Chondral or osteochondral lesions were found in 57 % of the arthroscopies. The mean Lysholm score in this subgroup was 55. The mean Lysholm score was significantly lower in women (50, SD 19) compared to men (59, SD 18, p < 0.001). Among the chondral lesion factors, only kissing (vs. non-kissing) lesions and multiple (vs. single) lesions influenced symptoms and function to a more than negligible degree. Microfracture in one or two articular cartilage defects was performed in 187 patients. The microfracture group had a significant lower mean Lysholm score (54, SD 18) than a group of patients (N = 71) undergoing ACL reconstruction group (67, SD 17, p < 0.001).

CONCLUSION

The study confirms that articular cartilage lesions are both common and cumbersome. Women seem to have more problems than men, whereas chondral lesion factors-such as localisation and size-seem to influence symptoms and function to a small degree. These aspects should be addressed when designing outcome studies, and should also be of interest to the orthopaedic surgeon-in the day-by-day clinical work. When treating these patients, our prime focus need to be on knee function rather than the cartilage defect as the relationship between the latter and the former is unclear.

LEVEL OF EVIDENCE

Case-control study, Level III.

Cell-based tissue engineering strategies used in the clinical repair of articular cartilage

One of the most important issues facing cartilage tissue engineering is the inability to move technologies into the clinic. Despite the multitude of current research in the field, it is known that 90% of new drugs that advance past animal studies fail clinical trials. The objective of this review is to provide readers with an understanding of the scientific details of tissue engineered cartilage products that have demonstrated a certain level of efficacy in humans, so that newer technologies may be developed upon this foundation. Compared to existing treatments, such as microfracture or autologous chondrocyte implantation, a tissue engineered product can potentially provide more consistent clinical results in forming hyaline repair tissue and in filling the entirety of the defect. The various tissue engineering strategies (e.g., cell expansion, scaffold material, media formulations, biomimetic stimuli, etc.) used in forming these products, as collected from published literature, company websites, and relevant patents, are critically discussed. The authors note that many details about these products remain proprietary, not all information is made public, and that advancements to the products are continuously made. Nevertheless, by understanding the design and production processes of these emerging technologies, one can gain tremendous insight into how to best use them and also how to design the next generation of tissue engineered cartilage products.

Return to Sport After Articular Cartilage Repair in Athletes' Knees: A Systematic Review

PURPOSE

To perform a systematic review of cartilage repair in athletes' knees to (1) determine which (if any) of the most commonly implemented surgical techniques help athletes return to competition, (2) identify which patient- or defect-specific characteristics significantly affect return to sport, and (3) evaluate the methodologic quality of available literature.

METHODS

A systematic review of multiple databases was performed. Return to preinjury level of sport was defined as the ability to play in the same or greater level (i.e., league or division) of competition after surgery. Study methodologic quality for all studies analyzed in this review was evaluated with the Coleman Methodology Score.

RESULTS

Systematic review of 1,278 abstracts identified 20 level I-IV studies for inclusion but only 1 randomized controlled trial. Twenty studies (1,117 subjects) were included. Subjects (n = 970) underwent 1 of 4 surgeries (microfracture [n = 529], autologous chondrocyte implantation [ACI, n = 259], osteochondral autograft [n = 139], or osteochondral allograft [n = 43]), and 147 were control patients. The rate of return to sports was greatest after osteochondral autograft transplantation (89%) followed by osteochondral allograft, ACI, and microfracture (88%, 84%, and 75%, respectively). Osteochondral autograft transplantation and ACI had statistically significantly greater rates of return to sports compared with microfracture (P < .001, P < .01; Fisher exact test).

CONCLUSIONS

Athletes may return to sports participation after microfracture, ACI, osteochondral autograft, or osteochondral allograft, but microfracture patients were least likely to return to sports. The athletes who had a better prognosis after surgery were younger, had a shorter preoperative duration of symptoms, underwent no previous surgical interventions, participated in a more rigorous rehabilitation protocol, and had smaller cartilage defects.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I-IV studies.

Medial Femoral Condyle Cartilage Defect Biomechanics: Effect of Obesity, Defect Size, and Cartilage Thickness

BACKGROUND

Medial femoral condyle (MFC) chondral defects cause knee pain. Clinical studies have shown worse functional outcomes and cartilage defect fill rates after microfracture in obese patients (BMI ≥30) and for defects with size ≥2 cm(2).

PURPOSE

To determine the effect of obesity, defect size, and cartilage thickness on the force sustained at the base of full-thickness MFC cartilage defects during weightbearing.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eight human cadaveric knees were loaded in 15° of flexion. A sensor measured force across the medial compartment. The area at the base of the defect protected from load, termed the "area of containment," was quantified, and loads simulating weightbearing for BMIs of 20, 30, and 40 were applied. A full-thickness cartilage defect was created on the MFC. Cycles of loads were applied for defect sizes with diameters of 6, 8, 10, 12, 14, 16, 18, and 20 mm. A second sensor recorded force at the base of the defect for defects with diameters of 14, 16, 18, and 20 mm.

RESULTS

Loads simulating BMI ≥30 led to a decrease in the area of containment for all defects ≥14 mm in diameter (P ≤ .038). Base of defect force increased for defects ≥16 mm in diameter (area, ≥2 cm(2)) between loaded and unloaded states (P ≤ .042) and for loads simulating BMI ≥30 (P ≤ .045). Cartilage rim thickness <2 mm showed higher base of defect force than did thickness ≥2 mm, for all BMI groups (P ≤ .025).

CONCLUSION

Increased force at the base of MFC cartilage defects was observed for weightbearing loads simulating BMI ≥30, for defect size ≥2 cm(2), and for rim thickness <2 mm. This may lead to a biomechanically unfavorable environment after microfracture in these patient subsets.

CLINICAL RELEVANCE

These biomechanical findings corroborate clinical studies that have noted worse outcomes after microfracture in patients with BMI ≥30 and cartilage defects of size ≥2 cm(2). Further clinical studies are needed to compare microfracture with other cartilage restoration procedures in these patient subsets.

Treatment of unstable osteochondritis dissecans in adults with autogenous osteochondral grafts (Mosaicplasty): long-term results

PURPOSE

the unstable osteochondritis dissecans (OCD-type II and III according to the ICRS classification) of the knee largher than > 2.5 cm(2) in adults are uncommon lesions and there is no consensus on how to treat them. Medium-term studies have reported good results using autogenous osteochondral plugs (mosaicplasty). The aim of this study is to analyze the long-term results of this technique for the treatment of unstable OCD in a selected group of adult patients.

METHODS

four patients with OCD at either one of the femoral condyles were included in this prospective study. The average age was 21.2 years (range, 18-24 years). The OCD lesions were classified as type II in three patients and type III in one patient and the average size was 3.8 cm(2) (range, 2.55-5.1 cm(2)). The lesions were treated in situ with a variable number of autogenous osteochondral plugs (Ø 4.5 mm(2)). The Modified Cincinnati, Lysholm II and Tegner scores were used for clinical and functional evaluation. Magnetic resonance arthrography (MRA) was performed before surgery and at 2, 5 and 10 years after surgery. A modified MOCART score was used to evaluate MRA findings.

RESULTS

the average follow-up duration was ten years and 6 months (range, 10-11 years). No complications occurred. At the final follow-up, all scores (clinical, functional and MOCART) improved. In all but one of the patients MRA showed complete osteochondral repair.

CONCLUSIONS

the fixation of large and unstable OCD lesions with mosaicplasty may be a good option for treating type II or III OCD lesions in adults. The advantages of this technique include stable fixation, promotion of blood supply to the base of the OCD fragment, and grafting of autologous cancellous bone that stimulates healing with preservation of the articular surface.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Current concepts review: Fractures of the patella

Fractures of the patella account for about 1% of all skeletal injuries and can lead to profound impairment due to its crucial function in the extensor mechanism of the knee. Diagnosis is based on the injury mechanism, physical examination and radiological findings. While the clinical diagnosis is often distinct, there are numerous treatment options available. The type of treatment as well as the optimum timing of surgical intervention depends on the underlying fracture type, the associated soft tissue damage, patient factors (i.e. age, bone quality, activity level and compliance) and the stability of the extensor mechanism. Regardless of the treatment method an early rehabilitation is recommended in order to avoid contractures of the knee joint capsule and cartilage degeneration.

For non-displaced and dislocated non-comminuted transverse patellar fractures (2-part) modified anterior tension band wiring is the treatment of choice and can be combined – due to its biomechanical superiority – with cannulated screw fixation. In severe comminuted fractures, open reduction and fixation with small fragment screws or new angular stable plates for anatomic restoration of the retropatellar surface and extension mechanism results in best outcome. Additional circular cerclage wiring using either typical metal cerclage wires or resorbable PDS/non-resorbable FiberWires increases fixation stability and decreases risk for re-dislocation. Distal avulsion fractures should be fixed with small fragment screws and should be protected by a transtibial McLaughlin cerclage. Partial or complete patellectomy should be regarded only as a very rare salvage operation due to its severe functional impairment.

Microfracture for the treatment of cartilage defects in the knee joint - A golden standard?

The evidence for the effectiveness of the microfracture procedure is largely derived from case series and few randomized trials. Clinical outcomes improve with microfracture for the most part, but in some studies these effects are not sustained. The quality of cartilage repair following microfracture is variable and inconsistent due to unknown reasons. Younger patients have better clinical outcomes and quality of cartilage repair than older patients. When lesion location was shown to affect microfracture outcome, patients with lesions of the femoral condyle have the best clinical improvements and quality of cartilage repair compared with patients who had lesions in other areas. Patients with smaller lesions have better clinical improvement than patients with larger lesions. The necessity of long postoperative CPM and restricted weight bearing is widely accepted but not completely supported by solid data. Maybe new developments like the scaffold augmented microfracture(6) will show even more consistent clinical and biological results as well as faster rehabilitation for the treatment of small to medium sized cartilage defects in younger individuals. All in all there is limited evidence that micro fracture should be accepted as gold standard for the treatment of cartilage lesions in the knee joint. There is no study available which compares empty controls or non-surgical treatment/physiotherapy with microfracture. According to the literature there is even evidence for self regeneration of cartilage lesions. The natural history of damaged cartilage seems to be written e.g. by inflammatory processes, genetic predisposition and other factors. Possibly that explains the large variety of the clinical outcome after micro fracture and possibly the standard tools for evaluation of new technologies (randomized controlled trials, case series, etc.) are not sufficient (anymore). Future technologies will be evaluated by big data from international registries for earlier detection of safety issues, for detection of subtle but crucial co-factors for failure and osteoarthritis as well as for lower financial burdens affecting industry and healthcare systems likewise.

Osteochondral Biopsy Analysis Demonstrates That BST-CarGel Treatment Improves Structural and Cellular Characteristics of Cartilage Repair Tissue Compared With Microfracture

OBJECTIVE

The efficacy and safety of BST-CarGel, a chitosan-based medical device for cartilage repair, was compared with microfracture alone at 1 year during a multicenter randomized controlled trial (RCT) in the knee. The quality of repair tissue of osteochondral biopsies collected from a subset of patients was compared using blinded histological assessments.

METHODS

The international RCT evaluated repair tissue quantity and quality by 3-dimensional quantitative magnetic resonance imaging as co-primary endpoints at 12 months. At an average of 13 months posttreatment, 21/41 BST-CarGel and 17/39 microfracture patients underwent elective second look arthroscopies as a tertiary endpoint, during which ICRS (International Cartilage Repair Society) macroscopic scoring was carried out, and osteochondral biopsies were collected. Stained histological sections were evaluated by blinded readers using ICRS I and II histological scoring systems. Collagen organization was evaluated using a polarized light microscopy score.

RESULTS

BST-CarGel treatment resulted in significantly better ICRS macroscopic scores (P = 0.0002) compared with microfracture alone, indicating better filling, integration, and tissue appearance. Histologically, BST-CarGel resulted in a significant improvement of structural parameters-Surface Architecture (P = 0.007) and Surface/Superficial Assessment (P = 0.042)-as well as cellular parameters-Cell Viability (P = 0.006) and Cell Distribution (P = 0.032). No histological parameters were significantly better for the microfracture group. BST-CarGel treatment also resulted in a more organized repair tissue with collagen stratification more similar to native hyaline cartilage, as measured by polarized light microscopy scoring (P = 0.0003).

CONCLUSION

Multiple and independent analyses in this biopsy substudy demonstrated that BST-CarGel treatment results in improved structural and cellular characteristics of repair tissue at 1 year posttreatment compared with microfracture alone, supporting previously reported results by quantitative magnetic resonance imaging.

Cartilage Defect Treatments: With or without Cells? Mesenchymal Stem Cells or Chondrocytes? Traditional or Matrix-Assisted? A Systematic Review and Meta-Analyses

Articular cartilage defects have been addressed by using multiple strategies. In the last two decades, promising new strategies by using assorted scaffolds and cell sources to induce tissue regeneration have emerged, such as autologous chondrocyte implantation (ACI) and mesenchymal stem cell implantation (MSCI). However, it is still controversial in the clinical strategies when to choose these treatments. Thus, we conducted a systematic review and meta-analyses to compare the efficacy and safety of different cartilage treatments. In our study, 17 studies were selected to compare different treatments for cartilage defects. The results of meta-analyses indicated that cell-based cartilage treatments showed significant better efficacy than cell-free treatments did (OR: 4.27, 95% CI: 2.19–8.34; WMD: 10.11, 95% CI: 2.69–16.53). Another result indicated that MACT had significant better efficacy than traditional ACI did (OR: 0.49, 95% CI: 0.30–0.82). Besides, the incidence of graft hypertrophy of MACT was slightly lower than that of traditional ACI (OR: 2.43, 95% CI: 1.00–5.94). Current data showed that the cell-based treatments and MACT are better options for cartilage treatments, but more well-designed comparative studies are still needed to enhance our understanding of different treatments for cartilage defects.

Osteochondral defects of the upper extremity treated with particulated juvenile cartilage transfer

We present the novel use of particulated juvenile cartilage transfer in the upper extremity. Our patient is an active duty solider with an osteochondral defect (OCD) of the capitellum that he sustained after an improvised explosive devise injury to his left elbow.

Arthroscopic antegrade drilling for unstable juvenile osteochondritis dissecans of the knee: mid-term results

PURPOSE

The aim of our study was to retrospectively review the mid-term clinical and imaging outcomes of unstable knee juvenile osteochondritis dissecans (JOCD) patients treated with antegrade drilling.

METHODS

Knee arthroscopy and antegrade drilling was performed on 63 knee JOCD patients between 2006 and 2012. Lysholm and Tegner, as well as International Knee Documentation Committee (IKDC), scores were recorded and compared preoperatively and at the latest follow-up. Knee radiographs and magnetic resonance imaging were used to examine lesion healing status.

RESULTS

The mean follow-up time was 4.7 years (range 2-7.3 years), and 52 patients finished the follow-up. The average defect size was 2.79 cm(2) (range 1-4 cm(2)). Forty three patients had excellent outcomes with full return to pre-injury activities and reported no symptom recurrence or deterioration over time. The overall healing rate was 82.7 % (43/52). The average Lysholm score was improved from 51.3 to 85.8 (P = 0.001). The mean Tegner activity level was improved from 3.7 to 6.7 (P = 0.013). And the mean IKDC score was improved from 55.7 to 73.2 (P = 0.007). On average, evidence of healing was observed at 11.3 months after surgery (range 6-18 months)

CONCLUSIONS

Our series showed good to excellent mid-term results in unstable knee JOCD patients who were treated by antegrade drilling. This technique is minimally invasive and effective, as well as cost effective.

LEVEL OF EVIDENCE

4.

The utility of ultrasound for diagnosing purulent infections of the upper extremity

BACKGROUND

The purpose of this study was to determine the test characteristics of formal ultrasound when used to diagnose upper extremity soft tissue abscess in the setting of suspected infection.

METHODS

We completed a retrospective chart review of all patients who had formal ultrasounds at our institution for the indication of diagnosing upper extremity abscess between July 2010 and July 2013. Using presence of purulence as the gold standard for diagnosis of abscess, we calculated the test characteristics of ultrasound. We then performed a series of logistic regression models with ultrasound being the independent variable of interest.

RESULTS

Using search criteria consistent with upper extremity abscess, we identified 512 patients who underwent ultrasound examinations during our study period. Of these, 178 met the enrollment criteria. Ultrasound reports revealed 110 negative findings, 37 definitively positive findings, and 31 ambiguous findings. Forty-four patients had a final diagnosis of abscess, and 15 of these patients had negative or ambiguous ultrasounds. The sensitivity of definitively positive ultrasound was 65.9 %. The specificity was 94.0 %. Positive predictive value (PPV) of a definitively positive ultrasound result was 78.4 %, and negative predictive value (NPV) of a definitively negative result was 90 %. Logistic regression demonstrated a statistically significant association between definitively positive ultrasound and abscess, but no association between ambiguous ultrasound and abscess after adjustment for significant covariates.

CONCLUSIONS

Ultrasound is not a sensitive method to detect the presence of abscess in the setting of upper extremity infection. However, in this population of patients with suspected abscess, the negative predictive value was high with and without the inclusion of ambiguous results, suggesting reasonable utility of ultrasound as a rule-out test.

LEVEL OF EVIDENCE

Diagnostic study, Level II.

Concomitant Osteochondral Autograft Transplantation and Fixation of Osteochondral Fragment for Treatment of a Massive Osteochondritis Dissecans: A Report of 8-Year Follow-up Results

Numerous procedures exist to treat osteochondritis dissecans (OCD); however, it remains a topic of debate which procedure is most ideal. When restoring a massive osteochondral defect, the use of only one procedure may not always allow complete filling of the defect. This case report presents a massive OCD with displaced osteochondral fragment and loose body in the knee joint that occupied almost all of the weight bearing area of the medial femoral condyle and was treated with concomitant osteochondral autograft transplantation and fixation of displaced osteochondral fragment. To our knowledge, this is a rare report on OCD treated with concomitant osteochondral autograft transplantation and fixation of displaced osteochondral fragment. At 8 years after surgery, the clinical outcome was excellent, and radiographs revealed congruence of the medial femoral condyle. The patient returned to sports activities. In massive and complex OCD lesions, individual techniques have limitations. Two or more techniques are needed to increase the rate of success.

Osteochondral autografts

The healing potential for articular cartilage lesions is limited due to many physiological, local and mechanical factors. Spontaneous healing of partial- and full-thickness lesions is slow, and subsequent tissue response is usually not durable. In symptomatic, and high-demand, patients, a definitive treatment modality must be offered which allows for a sustained recovery with minimal debilitation. Injuries, which damage the subchondral bone, heal with the formation of fibrocartilage. This tissue fails long-term survival because of its inability to withstand the variable cyclic loads and compression forces that it is subjected to. While regeneration of the damaged cartilage by an entirely new articular surface is a goal beyond current available techniques, repair of the osteochondral defects with normal hyaline cartilage is possible by various options. Osteochondral defects that are larger then 2 cm are best treated by osteochondral autograft technique. The short-term outcomes of the present series show excellent results.

Short-term clinical results of arthroscopic osteochondral fixation for elbow osteochondritis dissecans in teenaged baseball players

BACKGROUND

Reports regarding arthroscopic fixation of the osteochondral fragments for elbow osteochondritis dissecans (OCD) are few. This study assessed the clinical outcomes of arthroscopic fixation of unstable osteochondral fragments by using absorbable pins over a postoperative period of at least 1 year.

METHODS

The patients were 13 adolescent baseball players with a mean age of 14 years (range, 12-16 years) who underwent OCD of primary lesions at International Cartilage Repair Society grades III and IV. The patients were evaluated by using validated outcome measures at a mean follow-up period of 24 months (range, 12-50 months).

RESULTS

The mean (standard deviation) score in the disability/symptom section of the Disabilities of the Arm, Shoulder, and Hand improved from 12.4 (6.0) before the surgery to 0.5 (1.2) after the surgery, and the sports section improved from 74.5 (25.4) to 1.4 (5.2). The mean (standard deviation) extension improved from -11° (10.8) to -2° (3.9; P < .001). The mean (SD) flexion improved from 129° (11.6) to 137° (5.6; P = .040). All patients were able to resume playing baseball, and 9 (69%) resumed playing at the same position as before their injuries.

CONCLUSIONS

The clinical results of arthroscopic osteochondral fragment fixation in the teenaged baseball players with elbow OCD, albeit obtained over only a short period, were favorable. This arthroscopic treatment enables repair of lesions and is considered appropriate for unstable OCD during the adolescent growth spurt.

Impact of storage conditions on electromechanical, histological and histochemical properties of osteochondral allografts

BACKGROUND

Osteochondral allograft transplantation has a good clinical outcome, however, there is still debate on optimization of allograft storage protocol. Storage temperature and nutrient medium composition are the most critical factors for sustained biological activity of grafts before implantation. In this study, we performed a time-dependent in vitro experiment to investigate the effect of various storage conditions on electromechanical, histological and histochemical properties of articular cartilage.

METHODS

Osteochondral grafts derived from goat femoral condyles were frozen at -70 °C or stored at 4 °C and 37 °C in the medium supplemented with or without insulin-like growth factor-1 (IGF-1). After 14 and 28 days the cartilage samples were quantitatively analysed for electromechanical properties, glycosaminoglycan distribution, histological structure, chondrocyte viability and apoptosis. The results were compared between the experimental groups and correlations among different evaluation methods were determined.

RESULTS

Storage at -70 °C and 37 °C significantly deteriorated cartilage electromechanical, histological and histochemical properties. Storage at 4 °C maintained the electromechanical quantitative parameter (QP) and glycosaminoglycan expression near the normal levels for 14 days. Although hypothermic storage revealed reduced chondrocyte viability and increased apoptosis, these parameters were superior compared with the storage at -70 °C and 37 °C. IGF-1 supplementation improved the electromechanical QP, chondrocyte viability and histological properties at 37 °C, but the effect lasted only 14 days. Electromechanical properties correlated with the histological grading score (r = 0.673, p < 0.001), chondrocyte viability (r = -0.654, p < 0.001) and apoptosis (r = 0.416, p < 0.02). In addition, apoptosis correlated with glycosaminoglycan distribution (r = -0.644, p < 0.001) and the histological grading score (r = 0.493, p = 0.006).

CONCLUSIONS

Our results indicate that quality of allografts is better preserved at currently established 4 °C storage temperature. Storage at -70 °C or at 37 °C is unable to maintain cartilage function and metabolic activity. IGF-1 supplementation at 37 °C can enhance chondrocyte viability and improve electromechanical and histological properties of the cartilage, but the impact persists only 14 days. The correlations between cartilage electromechanical quantitative parameter (QP) and metabolic activity were detected. Our findings indicate that non-destructive assessment of cartilage by Arthro-BST is a simple and reliable method to evaluate allograft quality, and could be routinely used before implantation.

Knee Articular Cartilage Repair and Restoration Techniques: A Review of the Literature

CONTEXT

Isolated chondral and osteochondral defects of the knee are a difficult clinical challenge, particularly in younger patients for whom alternatives such as partial or total knee arthroplasty are rarely advised. Numerous surgical techniques have been developed to address focal cartilage defects. Cartilage treatment strategies are characterized as palliation (eg, chondroplasty and debridement), repair (eg, drilling and microfracture [MF]), or restoration (eg, autologous chondrocyte implantation [ACI], osteochondral autograft [OAT], and osteochondral allograft [OCA]).

EVIDENCE ACQUISITION

PubMed was searched for treatment articles using the keywords knee, articular cartilage, and osteochondral defect, with a focus on articles published in the past 5 years.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

In general, smaller lesions (<2 cm(2)) are best treated with MF or OAT. Furthermore, OAT shows trends toward greater longevity and durability as well as improved outcomes in high-demand patients. Intermediate-size lesions (2-4 cm(2)) have shown fairly equivalent treatment results using either OAT or ACI options. For larger lesions (>4 cm(2)), ACI or OCA have shown the best results, with OCA being an option for large osteochondritis dissecans lesions and posttraumatic defects.

CONCLUSION

These techniques may improve patient outcomes, though no single technique can reproduce normal hyaline cartilage.

Clinical Evaluation and Preoperative Planning of Articular Cartilage Lesions of the Knee

Articular cartilage injuries are quite common. Most studies and review articles on cartilage repair and restoration focus on the different techniques available to treat cartilage defects; however, few thoroughly discuss the initial evaluation of patients with these defects. Outcomes are intimately associated with appropriate patient selection and indications for treatment; therefore, understanding the initial evaluation and conservative treatment of cartilage defects is essential to achieving excellent outcomes after surgical intervention, regardless of the chosen procedure. In patients with cartilage injury, a careful history, physical examination, and imaging are required before treating the lesion to ensure the patient's symptoms are actually related to the defect. To address any special considerations, other factors must be considered to improve patient outcomes, including the status of the meniscus, assessing and treating malalignment or off-loading the patellofemoral compartment, and reconstructing any ligamentous deficiencies. It is important for medical providers to understand what cartilage lesions may be symptomatic and when to refer these patients to surgeons who manage cartilage injury.

Differentiating the extent of cartilage repair in rabbit ears using nonlinear optical microscopy

Nonlinear optical microscopy (NLOM) was used as a noninvasive and label-free tool to detect and quantify the extent of the cartilage recovery. Two cartilage injury models were established in the outer ears of rabbits that created a different extent of cartilage recovery based on the presence or absence of the perichondrium. High-resolution NLOM images were used to measure cartilage repair, specifically through spectral analysis and image texture. In contrast to a wound lacking a perichondrium, wounds with intact perichondria demonstrated significantly larger TPEF signals from cells and matrix, coarser texture indicating the more deposition of type I collagen. Spectral analysis of cells and matrix can reveal the matrix properties and cell growth. In addition, texture analysis of NLOM images showed significant differences in the distribution of cells and matrix of repaired tissues with or without perichondrium. Specifically, the decay length of autocorrelation coefficient based on TPEF images is 11.2 ± 1.1 in Wound 2 (with perichondrium) and 7.5 ± 2.0 in Wound 1 (without perichondrium), indicating coarser image texture and faster growth of cells in repaired tissues with perichondrium (p < 0.05). Moreover, the decay length of autocorrelation coefficient based on collagen SHG images also showed significant difference between Wound 2 and 1 (16.2 ± 1.2 vs. 12.2 ± 2.1, p < 0.05), indicating coarser image texture and faster deposition of collagen in repaired tissues with perichondrium (Wound 2). These findings suggest that NLOM is an ideal tool for studying cartilage repair, with potential applications in clinical medicine. NLOM can capture macromolecular details and distinguish between different extents of cartilage repair without the need for labelling agents.

Microfracture and osteochondral autograft transplantation are cost-effective treatments for articular cartilage lesions of the distal femur

BACKGROUND

Multiple techniques have been suggested for the treatment of isolated knee articular cartilage injuries. For smaller lesions (<2-5 cm(2)), microfracture and osteochondral autograft transplantation (OAT) are commonly used options. With an increasing focus on health care efficiency, analyzing the cost-effectiveness of treatment modalities has become increasingly important.

PURPOSE/HYPOTHESIS

The purpose of this study was to analyze the costs and outcomes of microfracture and OAT to compare their cost-effectiveness. The hypothesis was that microfracture would be more cost-effective.

STUDY DESIGN

Economic and decision analysis; Level of evidence, 2.

METHODS

A literature search was performed to identify studies comparing microfracture and OAT for the treatment of articular cartilage lesions of the distal femur in an adult population. Data from these studies including surgical time, failure rates, revision surgeries, outcome scores, and return to athletics were then incorporated into a constructed cost model using standard accounting methodology. The model was based on actual 2013 cost figures (in US dollars) for all procedure, operating room, and instrumentation costs.

RESULTS

Three studies, with a mean follow-up of 8.7 years, met the inclusion criteria of having evidence level 1 or 2 comparing microfracture and OAT. There was a cumulative 28.6% reoperation rate among patients undergoing microfracture compared with 12.5% among patients undergoing OAT. While both groups demonstrated significant improvements compared with preoperative levels, the only significant differences in any outcome score reported between the 2 procedures were the International Cartilage Repair Society (ICRS) score and patient-reported return to their previous sports activity level. While microfracture had a lower initial cost ($3100), these savings lessened over 1 year ($1843) and 10 years ($996). Microfracture was more cost-effective when comparing Lysholm and Hospital for Special Surgery scores, whereas OAT was more cost-effective when comparing Tegner and ICRS scores. There was a significantly lower cost for return to play in athletes after OAT versus microfracture at 1 year ($11,428 vs $16,953, respectively), 3 years ($12,856 vs $38,000, respectively), and 10 years ($32,141 vs $60,799, respectively).

CONCLUSION

Published level 1 and 2 clinical studies with a 10-year follow-up demonstrated that the net cost and cost-effectiveness of microfracture and OAT are comparable for the treatment of isolated articular cartilage lesions of the distal femur.

CLINICAL RELEVANCE

Given similar clinical outcomes, microfracture and OAT are both viable, cost-effective first-line treatment options for these injuries.

Instruments for reproducible setting of defects in cartilage and harvesting of osteochondral plugs for standardisation of preclinical tests for articular cartilage regeneration

Background

Standardisation is required in research, so are approval procedures for advanced therapy medical products and other procedures for articular cartilage therapies. The process of creating samples needs to be reproducible.

The aim of this study was to design, create and validate instruments (1) to create reproducible and accurate defects and (2) to isolate samples in the shape of osteochondral cylinders in a quick, reliable and sterile manner.

Methods

Adjustable instruments were created: a crown mill with a resolution of 0.05 mm and a front mill to create defects in articular cartilage and subchondral bone. The instruments were tested on knee joints of pigs from the slaughterhouse; 48 defects were created and evaluated. A punching machine was designed to harvest osteochondral plugs. These were validated in an in vivo animal study.

Results

The instruments respect the desired depth of 0.5 and 1.5 mm when creating the defects, depending on whether the person using the instrument is highly experienced (0.451 mm; confidence interval (CI): 0.390 mm; 0.512 mm and 1.403 mm; CI: 1.305 mm; 1.502 mm) or less so (0.369 mm; CI: 0.297 mm; 0.440 mm and 1.241 mm; CI: 1.141 mm; 1.341 mm). Eighty samples were taken from knee joints of Göttingen Minipigs with this punching technique. The time needed for the harvesting of the samples was 7.52 min (±2.18 min), the parallelism of the sides of the cylinders deviated by −0.63° (CI: −1.33°; 0.08°) and the surface of the cartilage deviated from the perpendicularity by 4.86° (CI: 4.154°; 5.573°). In all assessed cases, a sterile procedure was observed.

Conclusions

Instruments and procedures for standardised creation and validation of defects in articular cartilage and subchondral bone were designed. Harvesting of samples in the shape of osteochondral cylinders can now be performed in a quick, reliable and sterile manner. The presented instruments and procedures can serve as helpful steps towards standardised operating procedures in the field of regenerative therapies of articular cartilage in research and for regulatory requirements.

Effect of microfracture and autologous-conditioned plasma application in the focal full-thickness chondral defect of the knee: an experimental study on rabbits

Purpose

The aim of the present study was to evaluate the effect of microfracture and intraarticular autologous conditioned plasma (ACP) injection on cartilage regeneration in a focal full-thickness chondral defect model created in the knee joint.

Methods

Full-thickness chondral defects of 3 × 6 mm² were surgically created in right medial femoral condyles (MFC) of New Zealand rabbits, and the rabbits were then divided into three groups according to treatment: Group 1 received only microfracture (mfx), Group 2 received mfx plus intraarticular ACP, and Group 3 received mfx; the defect was covered by the periosteum, and then, ACP was applied subperiosteally and intraarticularly. Twelve weeks after injection, the animals were sacrificed and the femoral condyles were evaluated macroscopically and histologically by hematoxylin-eosin staining. Then, histological sections were scored using the International Cartilage Repair Society (ICRS) visual histological scale.

Results

Findings showed that in both mfx/ACP-treated groups, the defects were filled regularly and smoothly, the defects had a greater fill and good integration into the surrounding host tissue, and the repair matrix had more hyaline-like character. On the other hand, defects were filled with an irregular, fibrous cartilage in the mfx-treated group. Histological scores in Group 2 and Group 3 were better compared to Group 1.

Conclusion

In the present study, we were able to demonstrate a beneficial effect of intraarticular administration of ACP as a coadjuvant of microfractures in order to regenerate hyaline-like cartilage in full-thickness chondral lesions in a rabbit model.

Incidence of Manipulation Under Anesthesia or Lysis of Adhesions After Arthroscopic Knee Surgery

BACKGROUND

Arthrofibrosis after knee arthroscopy is a challenging complication. Previous studies reporting incidences of manipulation under anesthesia (MUA) or lysis of adhesions (LOA) after knee arthroscopy are limited by confounders such as small sample size and regional sampling bias.

PURPOSE

To investigate the incidence of MUA or LOA after common arthroscopic knee procedures.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

A national insurance database was retrospectively queried for arthroscopic knee procedures from 2007 to 2011. The incidence of postoperative MUA and LOA within 3 and 6 months postoperatively was determined for each of 13 common arthroscopic knee surgeries, including ligamentous reconstructive procedures, cartilage restoration procedures, and meniscal procedures.

RESULTS

A total of 330,714 unique patients who underwent knee arthroscopy were included in the study. The overall incidence of MUA was 0.06% to 6.00% by 3 months and 0.11% to 8.00% by 6 months postoperatively. The incidence of LOA was somewhat less, ranging from 0.04% to 4.00% by 3 months and 0.06% to 6.00% by 6 months postoperatively. Isolated arthroscopic partial meniscectomy had the lowest incidence of postoperative MUA and LOA, while multiligament reconstructions and meniscal transplants had the highest incidences.

CONCLUSION

The overall incidence of MUA and LOA after arthroscopic knee procedures is low but rises significantly as the number of concomitant procedures or complexity of the procedures increases. This information may be useful in counseling patients on the likelihood of MUA or LOA based on the type of arthroscopic knee procedure that is planned.

Experimental articular cartilage repair in the Göttingen minipig: the influence of multiple defects per knee

Background

A gold standard treatment for articular cartilage injuries is yet to be found, and a cost-effective and predictable large animal model is needed to bridge the gap between in vitro studies and clinical studies.

Ideally, the animal model should allow for testing of clinically relevant treatments and the biological response should be reproducible and comparable to humans. This allows for a reliable translation of results to clinical studies.This study aimed at verifying the Göttingen minipig as a pre-clinical model for articular cartilage repair by testing existing clinical cartilage repair techniques and evaluating the use of two defects per knee.

Methods

Sixteen fully mature Göttingen minipigs were used. The minipigs received bilateral trochlear osteochondral drill-hole defects or chondral defects (Ø 6 mm), either one defect per knee or two defects per knee. The defects were treated with one of the following: Matrix-induced autologous chondrocyte implantation (MACI), microfracture (MFx), autologous-dual-tissue transplantation (ADTT), autologous bone graft, autologous cartilage chips. Empty chondral and osteochondral defects were used as controls. MRI and CT were performed 3 and 6 month, histology was performed 6 month postoperative.

Results

The repair tissue varied in morphology from non-cartilaginous fibrous tissue to fibrocartilaginous tissue as seen on MRI, CT and histology at 6 month. The worst results were seen in the empty controls, while the best results were achieved with the MACI and ADTT treatment. The use of two defects per knee did not have any significant effect on the repair response.

Conclusion

The outcomes of the applied treatments were consistent with the outcomes in clinical studies and it was possible to apply two defects per knee. The Göttingen minipig model was easy to handle, cost-effective and provided predictable outcome. Based on this study the use of two defects per knee, one in the medial and one in the lateral trochlear facet, in male Göttingen minipigs is recommended.

Synoviocyte Derived-Extracellular Matrix Enhances Human Articular Chondrocyte Proliferation and Maintains Re-Differentiation Capacity at Both Low and Atmospheric Oxygen Tensions

Background

Current tissue engineering methods are insufficient for total joint resurfacing, and chondrocytes undergo de-differentiation when expanded on tissue culture plastic. De-differentiated chondrocytes show poor re-differentiation in culture, giving reduced glycosaminoglycan (GAG) and collagen matrix accumulation. To address this, porcine synoviocyte-derived extracellular matrix and low (5%) oxygen tension were assessed for their ability to enhance human articular chondrocyte expansion and maintain re-differentiation potential.

Methods

Porcine synoviocyte matrices were devitalized using 3 non-detergent methods. These devitalized synoviocyte matrices were compared against tissue culture plastic for their ability to support human chondrocyte expansion. Expansion was further compared at both low (5%), and atmospheric (20%) oxygen tension on all surfaces. Expanded cells then underwent chondrogenic re-differentiation in aggregate culture at both low and atmospheric oxygen tension. Aggregates were assessed for their GAG and collagen content both biochemically and histologically.

Results

Human chondrocytes expanded twice as fast on devitalized synoviocyte matrix vs. tissue culture plastic, and cells retained their re-differentiation capacity for twice the number of population doublings. There was no significant difference in growth rate between low and atmospheric oxygen tension. There was significantly less collagen type I, collagen type II, aggrecan and more MMP13 expression in cells expanded on synoviocyte matrix vs. tissue culture plastic. There were also significant effects due to oxygen tension on gene expression, wherein there was greater collagen type I, collagen type II, SOX9 and less MMP13 expression on tissue culture plastic compared to synoviocyte matrix. There was a significant increase in GAG, but not collagen, accumulation in chondrocyte aggregates re-differentiated at low oxygen tension over that achieved in atmospheric oxygen conditions.

Conclusions

Synoviocyte-derived matrix supports enhanced expansion of human chondrocytes such that the chondrocytes are maintained in a state from which they can re-differentiate into a cartilage phenotype after significantly more population doublings. Also, low oxygen tension supports GAG, but not collagen, accumulation. These findings are a step towards the production of a more functional, tissue engineered cartilage.

Return to sports after autogenous osteochondral mosaicplasty of the femoral condyles: 25 cases at a mean follow-up of 9 years

INTRODUCTION

Autogenous osteochondral mosaicplasty is the most common cartilage restoration technique in standard clinical practice. The purpose of this study was to evaluate the return to sports 9 years after mosaicplasty of the femoral condyles.

HYPOTHESIS

The long-term results of an osteochondral autograft show that patients can regain their pre-injury activity level.

MATERIAL AND METHODS

This study is based on a series of 25 patients with a mean age of 28.9 years (range, 16-44 years) who had stage 3 or 4 chondral lesions of the femoral condyles (according to the ICRS or ICRS-OCD scores). The origin of the lesion was osteochondritis dissecans (13 knees), osteochondral fracture sequelae (ten knees), or aseptic osteonecrosis (two knees). The average size of the lesion was 2.11 ± 0.9 cm(2). Ten patients (40%) had an associated procedure during the osteochondral autograft. The patients were assessed clinically (IKDC and Lysholm-Tegner scores) and radiographically by a reviewer independent of the team of operators.

RESULTS

All patients were re-examined at a mean follow-up of 9 years (range, 6-15 years), with 84% satisfied or very satisfied with the procedure. The average IKDC was 74.5 ± 18.5 points. The average Lysholm score was 87.3 ± 11.6 points. The average Tegner score ranged from 6.35 ± 1.53 points prior to surgery to 5.60 ± 1.64 points after surgery (P = 0.001). The average loss was 0.64 points for patients whose presurgery Tegner score was greater than or equal to 7 (P = 0.019) and 0.3 points if lower than 7. The radiologic evaluation of 21 patients showed complete osteointegration of the grafts in 90% of cases.

CONCLUSION

The results of the femoral condyle mosaic autografts are satisfactory, a mean of 9 years after surgery. The most active patients lowered their activity level while the more sedentary did not have to adapt their lifestyle.

Editorial commentary: osteoarticular transplant outcomes may deteriorate over time

Osteoarticular (OA) transplant hyaline cartilage may deteriorate, and ultimately result in "fibrocartilage" at 2 years. Long-term OA transplant outcomes may be inferior to autologous chondrocyte transplantation, yet this conclusion is based on a single, prospective comparative study. The promise of an ideally conceived, tissue-engineered, OA transplantation graft remains distant.

Systematic review of autogenous osteochondral transplant outcomes

PURPOSE

The goal of this systematic review was to present the current best evidence for clinical outcomes of osteochondral autograft transplantation to elucidate the efficacy of this procedure.

METHODS

PubMed, CINAHL, and the Cochrane Central Register of Controlled Trials were searched (key terms "knee," "osteochondral autograft transfer," or "mosaicplasty") to identify relevant literature between 1950 and 2013 in the English language. This evaluation included studies in pediatric and adult patients with grade 3 or 4 articular cartilage injuries; the studies had a minimum of 25 patients and at least 12 months of follow-up and compared osteochondral autograft transfers/mosiacplasty with another treatment modality. Articles were limited to full-text randomized controlled trials or cohort studies. Main outcomes studied were patient-reported and functional outcome, with secondary outcomes including effect of lesion size, return to sport and sport function, radiographic outcomes, and reoperation rates.

RESULTS

There were a total of 9 studies with 607 patients studied in this systematic review. When osteochondral autologous transfer/mosaicplasty (OATM) was compared with microfracture (MF), patients with OATM had better clinical results, with a higher rate of return to sport and maintenance of their sports function from before surgery. Meanwhile, patients who underwent MF trended toward more reoperations, with deterioration around 4 years after surgery. When compared with autologous chondrocyte implantation (ACI), clinical outcome improvement was not conclusive; however, at 10-year follow-up, a greater failure rate was found to be present in the OATM group.

CONCLUSIONS

Current evidence shows improved clinical outcomes with OATM when compared with preoperative conditions. These patients were able to return to sport as early as 6 months after the procedure. It could be suggested from the data that OATM procedures might be more appropriate for lesions that are smaller than 2 cm(2) with the known risk of failure between 2 and 4 years. Further high-quality prospective studies into the management of these articular cartilage injuries are necessary to provide a better framework within which to target intervention.

LEVEL OF EVIDENCE

Level II, systematic review of Level I and II studies.

The state of cartilage regeneration: current and future technologies

It is clear that mature human articular cartilage does not have the innate ability to regenerate. Due to this, much effort has been put forth to work on bestowing this ability. While early data focused on more basic outcomes such as percentage of defect fill, the tissue formed was a "cartilage scar" or "hyaline-like" tissue. Even with more advanced technologies, it is clear that no current procedure is able to reconstitute the native structure and function of true hyaline cartilage. As research advancement has somewhat plateaued in this regard, it is crucial that future work focuses on a multifactorial approach, treating the joint as an organ system. The purpose of this review is to update readers on the most recent literature and controversies surrounding articular cartilage regeneration. Specific focus will be placed on current technologies available in the USA and the basic science to support them.

Arthroscopic mosaicplasty: long-term outcome and joint degeneration progression

BACKGROUND

This study aims to document the long-term results in a group of patients treated with arthroscopic mosaicplasty for knee cartilage lesions, both in terms of clinical outcome and joint degeneration progression, evaluated by radiographs.

METHODS

26 patients (19 men and 7 women, mean age 29 years, mean BMI 23) treated arthroscopically with mosaicplasty for cartilage defects of the femoral condyles (mean/median/mode size 1.9 standard deviation, SD 0.6 cm(2)) were prospectively evaluated at 12 years follow-up. The clinical outcome was analyzed with IKDC and Tegner scores. Range of motion, transpatellar and suprapatellar circumferences were also measured. Radiographs with weight-bearing antero-posterior and Rosenberg projections were used for radiological evaluation in 18 patients, applying both Kellgren-Lawrence score and a direct joint line measurement to assess osteoarthritis.

RESULTS

A significant improvement in all clinical scores was obtained from the basal evaluation to the 12-year follow-up (IKDC subjective score from 36.8 standard deviation, SD 13.0 to 77.3 standard deviation, SD 20.6, P<0.0005; Tegner score from 2.9 standard deviation, SD 1.3 to 5.2 standard deviation, SD 2.5, P<0.0005), and better results in patients with a higher pre-injury activity level and those requiring fewer plugs. The radiographic evaluation showed significantly poorer Kellgren-Lawrence scores and a reduction of the joint line in the treated compartments. Knees with 3-4 plugs presented a significantly higher joint degeneration level with respect to those implanted with 1-2 plugs.

CONCLUSIONS

Mosaicplasty is an effective surgical option for small lesions of the femoral condyles. Although joint degeneration progression was present at 12 years, this did not affect significantly the clinical outcome which was satisfactory at long-term follow-up.

Arthroscopic airbrush assisted cell implantation for cartilage repair in the knee: a controlled laboratory and human cadaveric study

OBJECTIVE

The objective of this study was to investigate the feasibility of arthroscopic airbrush assisted cartilage repair.

METHODS

An airbrush device (Baxter) was used to spray both human expanded osteoarthritic chondrocytes and choncrocytes with their pericellular matrix (chondrons) at 1 × 10(6) cells/ml fibrin glue (Tissucol, Baxter) in vitro. Depth-dependent cell viability was assessed for both methods with confocal microscopy. Constructs were cultured for 21 days to assess matrix production. A controlled human cadaveric study (n = 8) was performed to test the feasibility of the procedure in which defects were filled with either arthroscopic airbrushing or needle extrusion. All knees were subjected to 60 min of continuous passive motion and scored on outline attachment and defect filling.

RESULTS

Spraying both chondrocytes and chondrons in fibrin glue resulted in a homogenous cell distribution throughout the scaffold. No difference in viability or matrix production between application methods was found nor between chondrons and chondrocytes. The cadaveric study revealed that airbrushing was highly feasible, and that defect filling through needle extrusion was more difficult to perform based on fibrin glue adhesion and gravity-induced seepage. Defect outline and coverage scores were consistently higher for extrusion, albeit not statistically significant.

CONCLUSION

Both chondrons and chondrocytes can be evenly distributed in a sprayed fibrin glue scaffold without affecting viability while supporting matrix production. The airbrush technology is feasible, easier to perform than needle extrusion and allows for reproducible arthroscopic filling of cartilage defects.

Articular cartilage repair using marrow stimulation augmented with a viable chondral allograft: 9-month postoperative histological evaluation

Marrow stimulation is frequently employed to treat focal chondral defects of the knee. However, marrow stimulation typically results in fibrocartilage repair tissue rather than healthy hyaline cartilage, which, over time, predisposes the repair to failure. Recently, a cryopreserved viable chondral allograft was developed to augment marrow stimulation. The chondral allograft is comprised of native viable chondrocytes, chondrogenic growth factors, and extracellular matrix proteins within the superficial, transitional, and radial zones of hyaline cartilage. Therefore, host mesenchymal stem cells that infiltrate the graft from the underlying bone marrow following marrow stimulation are provided with the optimal microenvironment to undergo chondrogenesis. The present report describes treatment of a trochlear defect with marrow stimulation augmented with this novel chondral allograft, along with nine month postoperative histological results. At nine months, the patient demonstrated complete resolution of pain and improvement in function, and the repair tissue consisted of 85% hyaline cartilage. For comparison, a biopsy obtained from a patient 8.2 months after treatment with marrow stimulation alone contained only 5% hyaline cartilage. These outcomes suggest that augmenting marrow stimulation with the viable chondral allograft can eliminate pain and improve outcomes, compared with marrow stimulation alone.

Outcomes in orthopedics and traumatology: translating research into practice

Clinical research is focused in generating evidence that is feasible to be applicable to practitioners. However, translating research-focused evidence into practice may be challenging and often misleading. This article aims is to pinpoint these challenges and suggest some methodological safeguards, taking platelet-rich plasma therapies and knee osteochondral injuries as examples. Studies and systematic reviews involving the following concepts will be investigated: clinically relevant outcomes, systematic errors on sample calculation, internal and external validity. Relevant studies on platelet-rich plasma for muscle-tendon lesions and updates on osteochondral lesions treatment were included in this analysis. Authors and clinicians should consider these concepts for the implementation and application of dissemination of the best evidence. Research results should be challenged by a weighted analysis of its methodological soundness and applicability. Level of Evidence V, Therapeutic Studies - Investigating the Results of Treatment.

Enhanced microfracture techniques in cartilage knee surgery: Fact or fiction?

The limited intrinsic healing potential of human articular cartilage is a well-known problem in orthopedic surgery. Thus a variety of surgical techniques have been developed to reduce joint pain, improve joint function and delay the onset of osteoarthritis. Microfractures as a bone marrow stimulation technique present the most common applied articular cartilage repair procedure today. Unfortunately the deficiencies of fibrocartilaginous repair tissue inevitably lead to breakdown under normal joint loading and clinical results deteriorate with time. To overcome the shortcomings of microfracture, an enhanced microfracture technique was developed with an additional collagen I/III membrane (Autologous, Matrix-Induced Chondrogenesis, AMIC^®). This article reviews the pre-clinical rationale of microfractures and AMIC^®, presents clinical studies and shows the advantages and disadvantages of these widely used techniques. PubMed and the Cochrane database were searched to identify relevant studies. We used a comprehensive search strategy with no date or language restrictions to locate studies that examined the AMIC^® technique and microfracture. Search keywords included cartilage, microfracture, AMIC^®, knee, Chondro-Gide^®. Besides this, we included our own experiences and study authors were contacted if more and non published data were needed. Both cartilage repair techniques represent an effective and safe method of treating full-thickness chondral defects of the knee in selected cases. While results after microfracture deteriorate with time, mid-term results after AMIC^® seem to be enduring. Randomized studies with long-term follow-up are needed whether the grafted area will maintain functional improvement and structural integrity over time.

Single-plug autologous osteochondral transplantation: results at minimum 16 years' follow-up

Different techniques have been proposed for the treatment of cartilage defects. Among the currently available options, autologous single-plug osteochondral transplantation is one of the few to be applied to address small and medium lesions. The goal of the current study was to document the long-term clinical outcome of a cohort of patients treated by this surgical strategy, which consists of harvesting a single osteochondral plug from a less weight bearing area of the knee and implanting it on the defect site by press-fit technique. Fifteen patients were enrolled. Age at surgery was 30.2±15.3 years, and body mass index was 22.5±3.0 kg/m(2). The inclusion criteria were clinical symptoms, such as knee pain or swelling, and grade III to IV chondral and osteochondral knee lesions. Patients were prospectively evaluated up to a mean of 17.5±3.5 years of follow-up by using Lysholm, International Knee Documentation Committee (IKDC) subjective, and Tegner scores. A significant improvement was noted in all clinical scores. In particular, the IKDC subjective score increased from 34.5±23.6 to 66.3±26.4 (P=.001). The Lysholm score showed a similar trend. From a baseline value of 47.8±29.5, the score increased to 79.8±24.6 at the last evaluation (P=.001). A significant increase in Tegner score was observed at the 2-year evaluation, with stable results up to the last follow-up. Four failures were reported, which in 3 cases occurred at mid- to long-term follow-up, confirming that this technique can be considered a suitable option for the treatment of small and medium chondral and osteochondral lesions in young patients.

Initial boost release of transforming growth factor-β3 and chondrogenesis by freeze-dried bioactive polymer scaffolds

In cartilage regeneration, bio-activated implants are used in stem and progenitor cell-based microfracture cartilage repair procedures. Our aim was to analyze the chondrogenic potential of freeze-dried resorbable polymer-based polyglycolic acid (PGA) scaffolds bio-activated with transforming growth factor-β3 (TGFB3) on human subchondral mesenchymal progenitor cells known from microfracture. Progenitor cells derived from femur heads were cultured in the presence of freeze-dried TGFB3 in high-density pellet culture and in freeze-dried TGFB3-PGA scaffolds for chondrogenic differentiation. Progenitor cell cultures in PGA scaffolds as well as pellet cultures with and without continuous application of TGFB3 served as controls. Release studies showed that freeze-dried TGFB3-PGA scaffolds facilitate a rapid, initial boost-like release of 71.5% of TGFB3 in the first 10 h. Gene expression analysis and histology showed induction of typical chondrogenic markers like type II collagen and formation of cartilaginous tissue in TGFB3-PGA scaffolds seeded with subchondral progenitor cells and in pellet cultures stimulated with freeze-dried TGFB3. Chondrogenic differentiation in freeze-dried TGFB3-PGA scaffolds was comparable to cultures receiving TGFB3 continuously, while non-stimulated controls did not show chondrogenesis during prolonged culture for 14 days. These results suggest that bio-activated, freeze-dried TGFB3-PGA scaffolds have chondrogenic potential and are a promising tool for stem cell-mediated cartilage regeneration.

Weight-bearing compared with non-weight-bearing following osteochondral autograft transfer for small defects in weight-bearing areas in the femoral articular cartilage of the knee

BACKGROUND

Patients are routinely kept non-weight-bearing for four to eight weeks following osteochondral autograft transfer to repair cartilage defects of the medial and/or lateral femoral condyle. Therefore, the objective of this novel study was to investigate whether postoperative weight-bearing restrictions affect the outcomes of cartilage repair when an osteochondral autograft transfer system is used to repair small defects in weight-bearing areas of femoral articular cartilage.

METHODS

This a retrospective comparative study. Following review of the charts on 567 consecutive arthroscopic osteochondral autograft transfers, three homogeneous groups of patients with consecutive cases were identified: group A, cases of patients who were non-weight-bearing following the procedure (n = 68); group B, cases of those who were non-weight-bearing following the procedure with concomitant anterior cruciate ligament reconstruction (n = 29); and group C, cases of those who were weight-bearing as tolerated following the procedure (n = 437). The cases of patients whose knees underwent second-look (repeat) arthroscopy were stratified into two subgroups: non-weight-bearing (n = 20) and weight-bearing as tolerated (n = 42). Graft position and manifestation of a repair-adjacent defect (Outerbridge grade-III or IV cartilage defect that develops adjacent to the original osteochondral autograft transfer repair) were assessed during second-look arthroscopy. Cartilage repair was retrospectively assessed from second-look arthroscopy pictures by a blinded, independent orthopaedic surgeon with use of the International Cartilage Repair Society macroscopic cartilage-repair assessment tool. Postoperative complication rates were compared among the three primary groups.

RESULTS

The mean grafted area was 0.72 cm(2) (range, 0.16 to 1.45 cm(2)) and 0.73 cm(2) (range, 0.16 to 1.80 cm(2)) for the non-weight-bearing and weight-bearing-as-tolerated second-look subgroups, respectively. The mean International Cartilage Repair Society score was 11.12 and 11.25 points (near-normal cartilage) for the non-weight-bearing and weight-bearing-as-tolerated subgroups (p = 0.71) at a mean follow-up of 42.7 and 33.0 months, respectively. There was no significant difference in the duration of follow-up (p = 0.58), repair-adjacent defect prevalence (p = 0.94), or graft position (p = 0.99) between the two subgroups. Weight-bearing-as-tolerated patients (group C) experienced significantly fewer deep vein thrombosis and arthrofibrosis complications compared with non-weight-bearing patients (groups A and B) (p < 0.001).

CONCLUSIONS

Postoperative weight-bearing restrictions did not affect mid-term cartilage repair outcomes in patients who underwent second-look arthroscopy when an osteochondral autograft transfer system was used to repair small defects in weight-bearing areas of cartilage of the medial and/or lateral femoral condyle.

LEVEL OF EVIDENCE

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

Functional outcomes after surgical management of articular cartilage lesions in the knee: a systematic literature review to guide postoperative rehabilitation

STUDY DESIGN

Systematic literature review.

OBJECTIVE

To systematically review the literature relative to muscle performance, knee joint biomechanics, and performance-based functional outcomes following articular cartilage repair and restoration surgical procedures in the knee.

BACKGROUND

Articular cartilage injuries are associated with functional limitations, poor quality of life, and the potential for long-term disability. This review systematically evaluates evidence related to muscle performance, joint biomechanics, and performance-based functional outcomes following articular cartilage procedures, and discusses their implications for rehabilitation.

METHODS

The online databases of PubMed (MEDLINE), CINAHL, SPORTDiscus, and Scopus were searched (inception to September 2013). Studies pertaining to muscle performance, knee joint biomechanics, and performance-based measures of function following articular cartilage procedure in the knee were included.

RESULTS

Sixteen articles met the specified inclusion criteria. Seven studies evaluated muscle performance, all showing persistent deficits in quadriceps femoris muscle strength for up to 7 years postprocedure. Quadriceps femoris strength deficits of greater than 20% were noted in 33% and 26% of individuals at 1 and 2 years following microfracture and autologous chondrocyte implantation (ACI), respectively. Two studies evaluated knee mechanics post-ACI, showing persistent deficits in knee kinematics and kinetics for up to 12 months postprocedure compared to uninjured individuals. Seven studies showed improved functional capacity (6-minute walk test) over time, and 3 studies showed persistent performance deficits during higher-level activities (single-leg hop test) for up to 6 years postprocedure. Five studies comparing weight-bearing protocols (accelerated versus traditional/current practice) following ACI found few differences between the groups in function and gait mechanics; however, persistent gait alterations were observed in both groups compared to uninjured individuals.

CONCLUSION

Significant quadriceps femoris strength deficits, gait deviations, and functional deficits persist for 5 to 7 years following ACI and microfracture surgical procedures. Future research regarding rehabilitation interventions to help mitigate these deficits is warranted. Level of Evidence Prognosis, level 2a-.

Arthroscopic debridement of unicompartmental arthritis: fact or fiction?

Patients with recurrent or mechanical symptoms of unicompartmental knee arthritis that have failed conservative management are candidates for surgical intervention. Surgical options include debridement, lavage, chondroplasty, bone marrow-stimulating techniques, chondrocyte transfer, and chondrocyte implantation. These techniques have been well studied but it is still unclear which technique is superior. Various factors need to be accounted for when choosing the proper technique; among the factors discussed are the patient's age and the size of the articular cartilage defect.

Strategies for osteochondral repair: Focus on scaffolds

Interest in osteochondral repair has been increasing with the growing number of sports-related injuries, accident traumas, and congenital diseases and disorders. Although therapeutic interventions are entering an advanced stage, current surgical procedures are still in their infancy. Unlike other tissues, the osteochondral zone shows a high level of gradient and interfacial tissue organization between bone and cartilage, and thus has unique characteristics related to the ability to resist mechanical compression and restoration. Among the possible therapies, tissue engineering of osteochondral tissues has shown considerable promise where multiple approaches of utilizing cells, scaffolds, and signaling molecules have been pursued. This review focuses particularly on the importance of scaffold design and its role in the success of osteochondral tissue engineering. Biphasic and gradient composition with proper pore configurations are the basic design consideration for scaffolds. Surface modification is an essential technique to improve the scaffold function associated with cell regulation or delivery of signaling molecules. The use of functional scaffolds with a controllable delivery strategy of multiple signaling molecules is also considered a promising therapeutic approach. In this review, we updated the recent advances in scaffolding approaches for osteochondral tissue engineering.