Second-generation arthroscopic autologous chondrocyte implantation for the treatment of degenerative cartilage lesions

Comparison of platelet-rich plasma formulations for cartilage healing: an in vitro study

BACKGROUND

Platelet-rich plasma (PRP) has been advocated as one treatment for cartilage tissue regeneration. To date, several different platelet-rich formulations have been available, but a deep knowledge of their composition and mechanism of action in a specific clinical use is needed. The aim of this study was to investigate the effect of various PRP formulations on human chondrocytes in vitro.

METHODS

Blood from ten human volunteers was used to prepare three formulations: (1) PRP with a relatively low concentration of platelets and very few leukocytes (P-PRP), (2) PRP with high concentrations of both platelets and leukocytes (L-PRP), and (3) platelet-poor plasma (PPP). Selected growth factors in the formulations were measured, and the in vitro effects of various concentrations were tested by exposing chondrocytes isolated from osteoarthritic cartilage of four different men and measuring cell proliferation, matrix production, and gene expression.

RESULTS

L-PRP contained the highest levels of growth factors and cytokines. All three formulations stimulated chondrocyte proliferation throughout the culture period evaluated; the only significant difference among the formulations was on day 7, when P-PRP induced greater cell growth compared with the other two formulations. P-PRP stimulated chondrocyte anabolism, as shown by the expression of type-II collagen and aggrecan, whereas L-PRP promoted catabolic pathways involving various cytokines. However, L-PRP induced greater expression of the hyaluronic acid synthase-2 gene and greater production of hyaluronan compared with P-PRP.

CONCLUSIONS

L-PRP and P-PRP induced distinct effects on human articular chondrocytes in vitro, possibly because of differences in the concentrations of platelets, leukocytes, growth factors, and other bioactive molecules. The identification of the optimal amounts and ratios of these blood components could ideally lead to a formulation more suitable for the treatment of cartilage lesions.

Treatment of "patellofemoral" cartilage lesions with matrix-assisted autologous chondrocyte transplantation: a comparison of patellar and trochlear lesions

BACKGROUND

Matrix-assisted autologous chondrocyte transplantation (MACT) has been shown to offer good outcomes at midterm follow-up, but results are heterogeneous among different patients and lesion types. Being part of the same joint, both patellar and trochlear cartilage lesions are commonly considered to be affected by the same treatment issues, and therefore, it is common practice to report results obtained treating these lesions together.

PURPOSE

To determine, in a large cohort of patients prospectively followed at midterm follow-up for patellofemoral chondral defects, if patellar and trochlear defects actually represent different clinical conditions with different healing potentials after cartilage treatment.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 49 consecutive patients with full-thickness patellofemoral chondral lesions of the knee were treated with MACT at the authors' institute and followed prospectively for a minimum follow-up of 5 years. Among these 49 patients, 28 were affected by patellar lesions, 17 were affected by trochlear lesions, and 4 had both patellar and trochlear defects. The clinical outcome was analyzed with International Knee Documentation Committee (IKDC) subjective, EuroQol visual analogue scale (EQ-VAS), Kujala, and Tegner scores.

RESULTS

A statistically significant improvement in all scores was observed after treatment. Patellar lesions required more realignment procedures and were more common in women. The comparative analysis showed better results for trochlear lesions compared with patellar lesions at all follow-ups, with mean IKDC scores at 5-year follow-up of 89.6 ± 12.7 and 69.7 ± 17.6, respectively (P < .0005). Better results were also shown for the mean Kujala score (92.4 ± 14.7 vs 81.5 ± 12.7, respectively; P = .012) and mean EQ-VAS score (90.0 ± 10.8 vs 81.9 ± 11.7, respectively; P = .027). Finally, the sport activity level evaluated with the Tegner score confirmed the same trend; even though neither patellar nor trochlear lesion groups reached the preinjury level, both improved after treatment, with a significantly higher improvement in the trochlear lesion group (5.9 ± 1.8 vs 3.9 ± 1.7, respectively; P < .0005).

CONCLUSION

Patient characteristics differ between patellar and trochlear cartilage defects, and moreover, the results obtained are significantly different, with a markedly good outcome in cases with trochlear lesions and less satisfactory results for patients affected by cartilage lesions of the patella. Thus, patellar and trochlear defects should be considered separately when evaluating the outcome of cartilage treatments in this anatomic region.

The John Insall Award: A minimum 10-year outcome study of autologous chondrocyte implantation

BACKGROUND

Autologous chondrocyte implantation (ACI) has demonstrated good and excellent results in over 75% of patients up to 10 years after surgery. Reports of longer-term outcomes, however, remain limited.

QUESTIONS/PURPOSES

The purposes of this study were to describe the (1) survivorship of ACI grafts; (2) the long-term functional outcomes using validated scoring tools after ACI; and (3) to provide an analysis of potential predictors for failure.

METHODS

Two hundred ten patients treated with ACI were followed for more than 10 years. Indications for the procedure included symptomatic cartilage defects in all compartments of the knee unresponsive to nonoperative measures. Mean age at surgery was 36 ± 9 years; mean defect size measured 8.4 ± 5.5 cm(2). Outcome scores were prospectively collected pre- and postoperatively at the last followup.

RESULTS

At a mean of 12 ± 2 years followup, 53 of 210 patients (25%) had at least one failed ACI graft. Nineteen of these patients went on to arthroplasty, 27 patients were salvaged with revision cartilage repair, and seven patients declined further treatment; three patients were lost to followup. The modified Cincinnati increased from 3.9 ± 1.5 to 6.4 ± 1.5, WOMAC improved from 39 ± 21 to 23 ± 16, Knee Society Score (KSS) knee score rose from 54 ± 18 to 79 ± 19, and KSS function from 65 ± 23 to 78 ± 17 (all p < 0.0001). The Physical Component of the SF-36 score increased from 33 ± 14 to 49 ± 18, whereas the Mental Component improved from 46 ± 14 to 52 ± 15 (both p < 0.001). Survivorship was higher in patients with complex versus salvage-type lesions (p = 0.03) with primary ACI versus ACI after prior marrow stimulation (p = 0.004) and with concomitant high tibial osteotomy (HTO) versus no HTO (p = 0.01).

CONCLUSIONS

ACI provided durable outcomes with a survivorship of 71% at 10 years and improved function in 75% of patients with symptomatic cartilage defects of the knee at a minimum of 10 years after surgery. A history of prior marrow stimulation as well as the treatment of very large defects was associated with an increased risk of failure.

Osteochondral scaffold reconstruction for complex knee lesions: a comparative evaluation

BACKGROUND

The primary aim of the present study is to evaluate the results obtained in challenging knee lesions with the implant of an osteochondral scaffold and concomitant treatment of all comorbidities. The secondary aim is to compare the results obtained with those found when a chondral scaffold was applied.

MATERIALS AND METHODS

Patients affected by complex lesions of the knee articular surface were included. "Complex cases" were defined according to the following criteria: previous clinical history of intra-articular fracture, lesion located at the tibial plateau, concurrent knee axial realignment procedure, concurrent meniscal scaffold or allograft implantation, and multiple articular surface lesions treated. Thirty-three patients were treated with the implantation of an osteochondral scaffold. The results of a homogeneous group of 23 patients previously treated and prospectively evaluated after implantation of a chondral scaffold were analyzed and compared.

RESULTS

IKDC subjective score improved significantly from pre-operative (40.4±14.1) to 12months' follow-up (69.6±17.0; p<0.0005) with a further improvement at the final evaluation at 24months (75.5±15.0; p=0.038). The same positive trend was confirmed by the VAS and Tegner scores. At final follow-up the group treated with the osteochondral scaffold presented a better subjective IKDC score with respect to the group treated with the chondral scaffold (p=0.034).

CONCLUSIONS

A regenerative procedure to address the entire osteochondral unit, together with the treatment of all comorbidities, might offer good results also in complex cases otherwise doomed to non-biological resurfacing.

LEVEL OF EVIDENCE III

Comparative study.

Unicompartmental osteoarthritis: an integrated biomechanical and biological approach as alternative to metal resurfacing

PURPOSE

Although traditionally not indicated for the treatment of osteoarthritis (OA), regenerative procedures are becoming a focus of increased interest due to their potential to provide pain relief and alter the progression of degenerative diseases. The purpose of this study was to assess whether a combined biomechanical and biological approach could offer good results in unicompartmental OA, thus delaying the need for unicompartmental arthroplasty in patients too young or refusing metal resurfacing.

METHODS

Forty-three patients (mean age = 40.1 ± 11 years, 33 men and 10 women, mean BMI = 25 ± 3) affected by unicompartmental OA (Kellegren-Lawrence score = 3) in stable joints were enrolled and treated consecutively. Fifteen patients were treated with osteotomy and osteochondral biomimetic scaffold implant (3 of them also with meniscal substitution), 11 with osteotomy and meniscal scaffold implant, 9 with osteotomy and meniscal allograft implant, and 8 with both cartilage and meniscal reconstruction, depending on the specific joint compartment main requirements. Clinical evaluation was performed at 3-year (2-4) median follow-up using the following scoring systems: IKDC subjective and objective, VAS for pain, and Tegner scores. Failures, adverse events, and complications were also reported.

RESULTS

The IKDC subjective score improved from 47.3 to 79.6 at the final evaluation (p < 0.0005), VAS improved from 6.1 to 2.3 (p < 0.0005), and also sport activity level evaluated with the Tegner score showed a significant improvement, from 2 (1-5) to 4 (3-10; p < 0.0005), even if without achieving the pre-injury level (6, p = 0.001). A further subanalysis confirmed the positive outcome obtained in all the treatment subgroups and showed a higher clinical improvement in patients under the age of 40 years (IKDC subjective 84.4 ± 13.2 vs 76.5 ± 17.3; p = 0.03).

CONCLUSION

This integrated biological and biomechanical approach produced a marked improvement at short-medium follow-up in patients affected by unicompartmental OA. Even though a good outcome was achieved at all ages, patients under the age of 40 years presented a greater clinical and subjective improvement. Longer follow-up studies are needed to show results over time and confirm this approach as an effective alternative to unicompartmental implants.

Continuous passive motion following cartilage surgery: does a common protocol exist?

Continuous passive motion (CPM) devices have the potential to improve the histological content as well as the rate and volume of chondrogenesis in repair tissue following chondral injury. However, clinical evidence is lacking to support broad implementation of CPM following cartilage restoration procedures. We searched PubMed, CINAHL, SPORTDiscus, and Cochrane for such terms as knee, continuous passive motion, CPM, ACI, ACT, autologous chondrocyte implantation, autologous chondrocyte transplantation, microfracture, marrow-stimulation technique, mosaicplasty, osteochondral autograft, and osteochondral allograft. Inclusion criteria were all English-language studies of human subjects, evidence levels I to IV, reporting the use of CPM following cartilage repair or restoration surgery in the knee. One hundred and seven studies met inclusion criteria. Sixty-three studies reported the use of CPM following autologous chondrocyte implantation; 28 reported the use of CPM following microfracture; 13 reported the use of CPM following osteochondral autograft; and 15 reported the use of CPM following osteochondral allograft (several studies reported > 1 type of cartilage procedure, which explains why the sum of all studies reporting a particular procedure [119] is greater than the number of studies included in the review [107]). Of the 5723 patients included, 60.8% were treated with autologous chondrocyte implantation, 23.1% were treated with microfracture, 6.4% were treated with osteochondral autograft, and 9.7% were treated with osteochondral allograft. Of the 6612 total defects, 5043 (76.3%) were tibiofemoral and 1569 (23.7%) were patellofemoral. Most reports of CPM use after cartilage restoration procedures did not include specific information on how it was implemented. Overall, the description of CPM protocols in published knee articular cartilage surgery studies was disappointing. The majority of studies did not describe common variables such as the duration of CPM therapy, the initiation of CPM therapy, and the initial range of motion used. The most commonly prescribed parameters within a CPM regimen are initiated on the first postoperative day, with an initial range-of-motion of 0 to 30 degrees and a frequency of 1 cycle per minute, and for 6 to 8 hours daily over 6 weeks. The lack of consistent standardized reporting of postoperative CPM protocols provides an impetus to researchers and clinicians to more clearly define and describe their use following knee articular surgery.

Does patient sex influence cartilage surgery outcome? Analysis of results at 5-year follow-up in a large cohort of patients treated with Matrix-assisted autologous chondrocyte transplantation

BACKGROUND

Sexual dimorphism in humans has already been documented at different levels, and preliminary findings also suggest the importance of patient sex on clinical outcome in the treatment of cartilage lesions.

PURPOSE

To document and analyze the influence of sex on clinical outcome in a large cohort of patients treated with a cartilage regenerative procedure for knee chondral lesions and prospectively followed at midterm follow-up.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 250 knees were treated with matrix-assisted autologous chondrocyte transplantation (MACT) and prospectively evaluated with International Knee Documentation Committee (IKDC), EuroQol visual analog scale (EQ-VAS), and Tegner scores at 1-, 2-, and minimum 5-year follow-ups to compare results obtained in men and women. The lesions were focal International Cartilage Repair Society grade III-IV chondral knee defects involving femoral condyles, trochleae, and patellae. Two homogeneous groups of 56 male patients and 56 female patients were then selected by a blinded statistician for a matched-pair analysis.

RESULTS

A statistically significant improvement in all the scores in both men and women was observed in the general population. The IKDC subjective score showed better results for men at all follow-up times: at 5 years, the mean IKDC subjective score was 79.5 ± 18.6 versus 64.3 ± 20.2 for men and women, respectively (P < .0005), and the same trend was confirmed with the EQ-VAS and Tegner scores. The matched-pair analysis confirmed the difference of final results achieved (74.1 ± 19.8 vs 63.7 ± 20.2, respectively; P = .006). However, men and women started with different preoperative levels, and the analysis of the improvement obtained was not significantly different. Finally, when scores were standardized for each patient, according to the mean score typical for the corresponding age and sex category in a healthy population, a sex-related difference was not confirmed at any of the follow-ups. Etiological factors, lesion site, and preinjury activity level differed in women and men of the general population and were the confounding factors responsible for the different outcome not confirmed by the analysis of homogeneous cohorts of patients.

CONCLUSION

Women have a different knee chondral lesion pattern and more often have unfavorable conditions related to the cause of injury, site, and activity level, and they also have lower raw, not standardized, scores. However, a matched-pair analysis with data standardized for the specific patient categories showed that, on equal terms, women have the same possibilities for successful outcome as men after surgical treatment for knee cartilage regeneration.

Treatment and Prevention of (Early) Osteoarthritis Using Articular Cartilage Repair-Fact or Fiction? A Systematic Review

Early osteoarthritis (OA) is increasingly being recognized in patients who wish to remain active while not accepting the limitations of conservative treatment or joint replacement. The aim of this systematic review was to evaluate the existing evidence for treatment of patients with early OA using articular cartilage repair techniques. A systematic search was performed in EMBASE, MEDLINE, and the Cochrane collaboration. Articles were screened for relevance and appraised for quality. Nine articles of generally low methodological quality (mean Coleman score 58) including a total of 502 patients (mean age range = 36-57 years) could be included. In the reports, both radiological and clinical criteria for early OA were applied. Of all patients included in this review, 75% were treated with autologous chondrocyte implantation. Good short-term clinical outcome up to 9 years was shown. Failure rates varied from 8% to 27.3%. The conversion to total knee arthroplasty rate was 2.5% to 6.5%. Although a (randomized controlled) trial in this patient category with long-term follow-up is needed, the literature suggests autologous chondrocyte implantation could provide good short- to mid-term clinical outcome and delay the need for total knee arthroplasty. The use of standardized criteria for early OA and implementation of (randomized) trials with long-term follow-up may allow for further expansion of the research field in articular cartilage repair to the challenging population with (early) OA.

Matrix assisted autologous chondrocyte transplantation for cartilage treatment: A systematic review

OBJECTIVES

Matrix-assisted autologous chondrocyte transplantation (MACT) has been developed and applied in the clinical practice in the last decade to overcome most of the disadvantages of the first generation procedures. The purpose of this systematic review is to document and analyse the available literature on the results of MACT in the treatment of chondral and osteochondral lesions of the knee.

METHODS

ALL STUDIES PUBLISHED IN ENGLISH ADDRESSING MACT PROCEDURES WERE IDENTIFIED, INCLUDING THOSE THAT FULFILLED THE FOLLOWING CRITERIA: 1) level I-IV evidence, 2) measures of functional or clinical outcome, 3) outcome related to cartilage lesions of the knee cartilage.

RESULTS

The literature analysis showed a progressively increasing number of articles per year. A total of 51 articles were selected: three randomised studies, ten comparative studies, 33 case series and five case reports. Several scaffolds have been developed and studied, with good results reported at short to medium follow-up.

CONCLUSIONS

MACT procedures are a therapeutic option for the treatment of chondral lesions that can offer a positive outcome over time for specific patient categories, but high-level studies are lacking. Systematic long-term evaluation of these techniques and randomised controlled trials are necessary to confirm the potential of this treatment approach, especially when comparing against less ambitious traditional treatments.

Treatment of cartilage lesions: what works and why?

Cartilage injuries have a high incidence and a high impact on society. In an attempt to fulfill patients' expectations and successfully treat this pathology, various techniques have been developed over the years. Treatments proposed for cartilage lesions are described with their rationale and indications, ranging from conservative measures to surgical approaches, reparative or regenerative. Among the numerous and heterogeneous procedures proposed over time to treat cartilage defects none has clearly proven to lead to a hyaline articular surface nor to offer better clinical results. Regenerative procedures have been introduced as ambitious techniques that aim to overcome the limitations of the more traditional reparative approaches and restore the articular surface with a hyaline-like tissue; improvement in tissue engineering with new scaffolds as well as new regenerative options involving growth factors or MSCs are currently being investigated as promising solutions to further improve the treatment of cartilage lesions. However, the current literature findings are not conclusive. Randomized controlled trials are necessary to evaluate new regenerative approaches, to show clearly advantages and disadvantages with respect to the more traditional procedures, besides their potential, limits, and indications to improve the treatment of patients affected by chondral and osteochondral lesions. Since clear and commonly accepted treatment algorithms are not available in the literature, the massively increasing number of controversial results may be confusing for the orthopaedic surgeon who has to choose the proper management of patients with cartilage lesions. Thus, the results obtained through the study of the authors' 20 years' experience in cartilage treatment were analyzed to give some indications on the potential and limits of different treatment approaches available in clinical practice.

Matrix-assisted autologous chondrocyte transplantation for cartilage regeneration in osteoarthritic knees: results and failures at midterm follow-up

BACKGROUND

Young patients with osteoarthritic knees are a challenging population because of a combination of high functional demands and limited indication for joint replacement.

PURPOSE

To analyze the potential of the cartilage regenerative approach by documenting the results and failures of matrix-assisted autologous chondrocyte transplantation (MACT) at midterm follow-up.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Forty-four patients affected by cartilage lesions in osteoarthritic knees underwent MACT as a salvage procedure. The mean age at surgery was 42 years (range, 20-58 years), and the average defect size was 4 cm(2) (range, 1.5-9 cm(2)). Patients were prospectively evaluated with the subjective International Knee Documentation Committee (IKDC), EuroQol visual analog scale (EQ-VAS), and Tegner scores preoperatively; at 1, 2, and 5 years; and at a final assessment at 9 years' mean follow-up. Adverse events and failures were also reported.

RESULTS

A statistically significant improvement was observed in all scores from the initial evaluation to the final follow-up. The mean ± standard deviation IKDC subjective score improved from 38.0 ± 15.8 to 67.0 ± 18.3 at 2 years (P < .0005), with a subsequent decrease to 57.8 ± 20.6 at the final follow-up (P = .012). The same trend was confirmed by the EQ-VAS score. The activity level revealed by the Tegner score improved at all follow-ups but without achieving the preinjury level. The analysis of the influencing factors showed the importance of the meniscus condition, revealing a significantly inferior outcome in knees with previous or combined partial meniscectomy procedures. During the study period, 12 patients had failed results, producing a cumulative failure rate of 27.3%. At the last evaluation, half of the patients considered their condition not better than before the treatment, and 39% would not repeat the treatment considering the results obtained.

CONCLUSION

Despite a statistically significant improvement, the clinical outcome was poor. A higher improvement could be obtained in patients who had not undergone previous or combined meniscectomies, but this was limited over time. The failure rate was also high, regardless of the degree of osteoarthritis. Tissue-engineered cartilage implantation is questionable for this indication, and the limits of this scaffold-based procedure have to be considered if it is used as a salvage procedure for young patients affected by knee osteoarthritis.

New trends for knee cartilage regeneration: from cell-free scaffolds to mesenchymal stem cells

In the last decade, huge steps forward have been made in the field of cartilage regeneration. The most recent trend for treating chondral/osteochondral lesions is based on the application of smart biomaterials that could lead to "in situ" regeneration of not only cartilage, but also subchondral bone, preferably through a single step procedure to reduce the costs and the morbidity for the patient. This innovative approach is currently under investigation as several "scaffolds" have been proposed in clinical practice, with or without the aid of cells, with the opportunity, in the second case, of bypassing the strict limits imposed by cell manipulation regulations. Furthermore, the fascinating potential of mesenchymal stem cells has recently opened new paths of research to discover how and whether these powerful entities can really contribute to tissue regeneration. The first clinical trials have been published but further high quality research is needed to understand their mechanisms of action, their limits, and their clinical efficacy.

Surgical treatment for early osteoarthritis. Part I: cartilage repair procedures

Young patients with early osteoarthritis (OA) represent a challenging population due to a combination of high functional demands and limited treatment options. Conservative measures such as injection and physical therapy can provide short-term pain relief but are only palliative in nature. Joint replacement, a successful procedure in the older population, is controversial in younger patients, who are less satisfied and experience higher failure rates. Therefore, while traditionally not indicated for the treatment of OA, cartilage repair has become a focus of increased interest due to its potential to provide pain relief and alter the progression of degenerative disease, with the hope of delaying or obviating the need for joint replacement. This review of cartilage repair techniques will discuss currently available procedures, specifically pertaining to experiences in the setting of early OA. Level of evidence IV.