Controversies in regenerative medicine: should knee joint osteoarthritis be treated with mesenchymal stromal cells?

Knee joint osteoarthritis is a complex immunological and degenerative disease. Current treatment strategies fail to alter its progression. Mesenchymal stromal cell (MSC) therapy for osteoarthritis has been object of research for more than 30 years. The aim of MSC therapy is intended to be holistic, with regeneration of all affected knee joint structures. The paracrine effect of the MSC secretome has been shown to be central for the regenerative capacity of MSCs. Activation of local knee-joint-specific MSCs leads to an immunomodulatory, anti-catabolic, anti-apoptotic and chondrogenic stimulus. Preclinical models have demonstrated the symptom- and disease-modifying effects of MSC therapy. At the bedside, there is evidence that autologous and allogeneic MSC therapy shows significant improvement in symptom-modifying and functional outcome. Despite this, a variety of contradictory clinical outcomes are available in the literature. The effectiveness of MSC therapy is still unclear, although there have been promising results. Regarding the diversity of cell sources, isolation, culture protocols and other factors, a comparison of different studies is difficult. Clinical translation of disease-modifying effects has not yet been shown. This narrative review presents a controversial overview of the current preclinical and clinical studies on MSC therapy in knee joint osteoarthritis.

Microfracture combined with anterior cruciate ligament reconstruction compared to isolated microfractures for osteochondral lesions.

There is limited evidence whether increased growth-factor and stem-cell influx during bone tunnel drilling for ACL-reconstruction enhances clinical results of microfracture treatment of small cartilage defects. The goal of this study was to compare clinical and radiological results in patients treated with microfracture alone and patients treated with microfracture plus ACL-reconstruction. A total of 67 patients that were either treated with microfracture alone (primary stable knees, n= 40) or microfracture plus ACL-reconstruction (ACL deficient knees, n= 27) were included and prospectively evaluated. Subjects were preoperatively assessed radiologically using the MR-based AMADEUS-score (Area Measurement and Depth & Underlying Structures) and clinically using the Lysholm-score before the intervention. At minimum 24-month follow-up, the regenerate tissue was assessed by the MR-based MOCART-score (Magnetic resonance observation of cartilage repair tissue) and by use of the Lysholm-Tegner-score for clinical evaluation. Preoperatively both groups had similar AMADEUS-scores. The Lysholm-score was significantly higher in the microfracture group (p < 0.001). In the postoperative assessment there was a significant difference (p = 0.04) in the MOCART-score in favor of the microfracture plus ACL-reconstruction group. The Lysholm-score significantly improved (p <0.001) in the microfracture plus ACL-reconstruction group and was significantly higher than in the microfracture group (p = 0.004). Conclusion: A combination of microfracture and ACL-reconstruction leads to comparable functional results, yet superior MOCART-scores as compared to microfracture alone. ACL reconstruction enhances biological healing responses in microfracture treated cartilage and thus improves clinical outcomes by additional bone marrow influx from bone tunnels.

What are the factors to affect outcome and healing of meniscus bucket handle tears?

INTRODUCTION: The purpose of this study is to identify patient, meniscus rupture and surgical characteristics that influence the outcome and clinical healing following operative repair of bucket handle tears. METHODS: Between 02/2006 and 10/2012, a total of 38 patients (14 women, 24 men) with bucket handle tears underwent surgical meniscus repair. There were 27 isolated repairs and 11 with concomitant anterior cruciate ligament (ACL) replacement. Patients were analyzed on an average of 44.4 months (range 15-96 months) after surgery by the use of standardized subjective scoring instruments [Lysholm, International Knee Documentation Committee (IKDC), Knee Injury and Osteoarthritis Outcome Score (KOOS) and Tegner Activity Scale (TAS)]. To identify factors affecting the outcome and suture survival, patient-specific, trauma-specific as well as meniscus- and surgery-specific factors were collected. Patients were divided in two groups with healed menisci (group 1) and re-rupture subjects (group 2). Meniscus re-rupture was defined as a clinical failure. RESULTS: There were 25 patients with healed menisci and 13 (34.2%) that sustained re-rupture and underwent either partial meniscectomy (n = 8) or re-suture (n = 5). Group 1 achieved slightly higher outcome compared to group 2 [Lysholm: 87.8 vs. 84.3 (p = 0.35), IKDC: 86.9 vs. 85.7 (p = 0.67), KOOS: 91.3 vs. 90.5 (p = 0.74)]. TAS was better for group 2 [5.9 vs. 6.8 (p = 0.36)]. Strong impact to result in a significantly increased outcome was identified for higher age, subjective knee joint stability, high preoperative Lysholm Score, short trauma-to-repair time, previous ACL reconstruction and a smaller number of sutures to fulfill meniscus repair. Lower patient age, male gender and higher activity level had the strongest impact to provoke re-rupture. CONCLUSION: Clinical outcome after meniscus bucket handle suture is satisfying. Re-rupture rate among this collective was 34.2%. Clear risk factors were identified for diminished clinical healing and outcome.

Spontaneous Minced Cartilage Procedure for Unexpectedly Large Femoral Condyle Surface Defect.

Articular cartilage defects at the knee joint are being identified and treated with increasing frequency. Chondrocytes may have strongest potential to generate high-quality repair tissue within the defective region, in particular when large diameter defects are present. Autologous chondrocyte implantation is not available in every country. We present a case where we spontaneously covered an acute cartilage defect, which was significantly larger than expected and loose during initial arthroscopic inspection after reading preoperative MRI, by mincing the separated fragment and directly implanting the autologous cartilage chips into the defective region.

Current status of anti-inflammatory therapy for posttraumatic osteoarthritis.

Although there is ample evidence that intra-articular injuries are associated with the up-regulation of pro-inflammatory cytokines, the success of anti-inflammatory, disease-modifying treatments to prevent posttraumatic osteoarthritis (PTOA) remain uncertain. To summarize the current status of anti-inflammatory therapy for PTOA, we conducted a systematic review. 9 clinical studies in humans were identified applying anti-inflammatory agents to prevent or treat PTOA. A total of 347 patients aged an average 41 ±â€ˆ14 years were included in this review. 5 studies had comparable designs with randomized allocation. Those studies of course had a statistically significant higher Coleman Methodology Score (65 ±â€ˆ6) than the case-control studies (39 ±â€ˆ13, p = 0.013). The most frequently reported main outcome parameter was pain assessed by different scales (n = 7), the most examined joint the knee (n = 7). The majority of the analyses (n = 6) focused on the intra-articular (IA) application of hyaluronic acid (HA) reporting mainly positive effects. One study stated positive results following IA administration of Interleukin 1 receptor antagonist in -patients presenting rupture of the anterior cruciate ligament. Platelet-rich plasma was also used to relieve symptoms following acute injury, but the study quality was too low to conclude any effects. Although the initial data, especially regarding IA HA injection, are encouraging, study designs differ substantially. Therefore, current data does not allow us to conclude that anti-inflammatory therapy following acute injuries has beneficial effects on short- or long-term outcomes.

Alignment does not influence cartilage T2 in asymptomatic knee joints.

PURPOSE: To investigate whether the static knee alignment affects articular cartilage ultrastructures when measured using T2 relaxation among asymptomatic subjects. METHODS: Both knee joints (n = 96) of 48 asymptomatic volunteers (26 females, 22 males; 25.4 ± 1.7 years; no history of major knee trauma or surgery) were evaluated clinically (Lysholm, Tegner) and by MRI (hip-knee-ankle angle, standard knee protocol, T2 mapping). Group (n = 4) division was as follows: neutral (<1° varus/valgus), mild varus (2°-4° varus), severe varus (>4° varus) and valgus (2°-4° valgus) deformity with n = 12 subjects/group; n = 24 knees/group. Regions of interest (ROI) for T2 assessment were placed within full-thickness cartilage across the whole joint surface and were divided respecting compartmental as well as functional joint anatomy. RESULTS: Leg alignment was 0.7° ± 0.5° varus among neutral, 3.0° ± 0.6° varus among mild varus, 5.0° ± 1.1° varus among severe varus and 2.5° ± 0.7° valgus among valgus group subjects and thus significantly different. No differences between the groups emerged from clinical measures. No morphological pathology was detected in any knee joint. Global T2 values (42.3 ± 2.3; 37.7-47.9 ms) of ROIs placed within every knee joint per subject were not different between alignment groups or between genders, respectively. CONCLUSION: Static frontal plane leg malalignment does not affect cartilage ultrastructure among young, asymptomatic individuals as measured by T2 quantitative imaging. LEVEL OF EVIDENCE: Cross-sectional study, Level II-III.

[Cartilage biopsy for autologous chondrocyte implantation (ACI)]. / Die Knorpelbiopsie im Rahmen der autologen Knorpelzelltransplantation (ACT).

Autologous chondrocyte implantation (ACI) is an established two-step procedure for the treatment of full-thickness cartilage defects of the knee. Cartilage harvest from the affected knee joint represents the first step of this procedure and is essential for further in vitro expansion of autologous chondrocytes. Nevertheless, the cartilage biopsy process itself is underrepresented in the scientific literature and currently there is only a limited amount of data available addressing this process. Biopsy location as well as the technique itself and instruments used for cartilage collection are not well defined and only little standardisation can be found. The article describes the relevant aspects of the biopsy in the context of ACI with regard to the literature available. Follow-up studies to better define and standardise the cartilage biopsy process are thus required.

Reoperative characteristics after microfracture of knee cartilage lesions in 454 patients.

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

Clinical outcome following the first-line, single lesion microfracture at the knee joint.

CASE SERIES: Level of evidence, 4. BACKGROUND: Arthroscopic microfracture of chondral defects across the knee joint is a frequent treatment modality. There is only limited information on the clinical outcome in patients without previous surgery and single lesions. PURPOSE: Evaluation of clinical outcome following microfracture in patients without previous surgery and single lesions and identification of prognostic factors. METHODS: Inclusion criteria were patients with single-lesion knee joint first-line microfracturing at minimum 2 years postoperatively. Charts were reviewed to identify patient and defect characteristics. Clinical outcome was evaluated by IKDC and Lysholm knee scores, Tegner activity scale and a numeric analogue scale (NAS) for function and pain (10 = highest possible function, no pain). RESULTS: Totally, 145 patients (age at operation 47.92 ± 15.7) met inclusion criteria. Average defect size was 2.7 ± 1.9 cm(2). Postoperatively, IKDC was 73.1 ± 18.5, Lysholm 77.6 ± 19.1, Tegner 4.5 ± 1.7, NAS pain 6.5 ± 2.6 and NAS function 6.4 ± 2.3. Significantly better clinical outcome was observed in male patients than in female patients. Regression analysis including all patient and defect characteristics highlighted that singly the parameter shorter symptom duration (P = 0.018) significantly predicted an improved postoperative clinical outcome. CONCLUSION: Microfracturing results in a satisfying clinical outcome, but no full recovery in patients without previous surgery and single lesions. Specific parameters facilitate outcome prognosis and therefore may aid in indicating surgery.

[Factors that influence clinical outcome following autologous chondrocyte implantation for cartilage defects of the knee]. / Einflussfaktoren auf das Behandlungsergebnis nach autologer Knorpelzelltransplantation (ACT) am Kniegelenk.

AIM: Since its introduction in 1994, autologous chondrocyte implantation (ACI) has become an established surgical treatment for symptomatic isolated cartilage defects of the knee. Success rates vary between 80 and 95% and the clinical outcome seems to depend on various individual factors. The aim of the present review article is to summarise factors that affect clinical outcome following ACI for treatment of symptomatic cartilage defects of the knee based upon the scientific literature available on this topic. METHODS: The present publication represents a non-systematic review including publications which were considered relevant describing factors that influence clinical outcome following ACI for treatment of symptomatic full thickness cartilage defects of the knee. In order to identify relevant literature concerning complications following cartilage repair, medical databases including "medline", "ovid" and "web of science" were searched for the terms "autologous chondrocyte implantation", "autologous chondrocyte transplantation", "prognostic factor", "clinical outcome", "cartilage repair", "cartilage defect" and "cartilage regeneration". The literature search was performed in April 2010. RESULTS: Factors that influence clinical outcome following ACI for treatment of cartilage defects of the knee include patient-specific parameters on the one hand, such as body mass index, nicotine abusus, patients age, prior surgical treatment, duration of symptoms and more, and defect characteristics such as containment, defect location, defect size, number of defects treated, on the other hand. Furthermore, surgical technique, cell quality and rehabilitation seem to significantly influence the clinical outcome following autologous chondrocyte implantation. Among all factors identified as relevant for clinical outcome, some of these parameters are fixed and cannot be changed by either the surgeon nor the patient, while others can be influenced and even changed during the treatment and rehabilitation of a patient who underwent ACI. CONCLUSION: Knowledge of all relevant parameters that influence clinical outcome following ACI is essential in order to achieve an optimal clinical outcome in patients with cartilage defects of the knee. This paper presents a review of the scientific literature available which focuses on the questions as to what parameters influence the outcome of a patient following ACI for treatment of cartilage defects of the knee. No isolated factors could be identified that influence the outcome following ACI alone, but it seems that clinical outcome is influenced by many different parameters. These parameters should be considered carefully, at the time of decision about what kind of treatment is applied. Furthermore, the patient should be informed especially about those parameters which can be influenced by him-/herself in order to create good prerequisites for the surgical treatment.

[Chondrocytes - one cell type, different subpopulations : characteristics and behavior of different types of chondrocytes and implications for tissue engineering applications]. / Chondrozyten - ein Zelltyp, verschiedene Subpopulationen : Merkmale und Verhalten verschiedener Chondrozyten und Implikationen für deren Einsatz zum "Tissue Engineering"

Chondrocytes represent the most important cell source for engineering of cartilaginous tissues. Depending on the tissue type and the localization within the tissue, these cells may behave differently. Numerous studies have been done to compare articular, nasal, auricular, and costal chondrocytes in order to evaluate differences between knee and ankle joint cartilage and to investigate topographical variations within an articular joint. Moreover, the zonal structure of articular cartilage needs to be considered because it leads to phenotypical differences between chondrocytes of the superficial and the deeper zones. Several studies indicate, however, that even differentiated chondrocytes demonstrate a certain plasticity and strive to adapt their phenotypes to a new mechanical and biochemical environment. The aim of this review is to report on similarities and differences of chondrocytes from different tissues, zones, and topographical locations. In particular, an overview of recent results from comparative studies is presented, and possible consequences for the design of tissue engineering models are discussed.

T2 assessment and clinical outcome following autologous matrix-assisted chondrocyte and osteochondral autograft transplantation.

OBJECTIVE: Both, matrix-assisted chondrocyte transplantation (MACT) and osteochondral autograft transplantation (OCT), are applied for treatment of articular cartilage defects. While previous clinical studies have compared the respective outcome, there is no such information investigating the ultrastructural composition using T2 mapping comparing cartilage T2 values of the repair tissue (RT). METHODS: Eighteen patients that underwent MACT or OCT for treatment of cartilage defects at the knee joint (nine MACT, nine OCT) were matched for gender (one female, eight male pairs), age (33.8), body mass index (BMI) (28.3), defect localization, and postoperative interval (41.6 months). T2 assessment was accomplished by T2 maps, while the clinical evaluation included the Lysholm and Cincinnati knee scores, a visual analogue scale (VAS) for pain, the Tegner activity scale, and the Short Form-36. RESULTS: Global T2 values of healthy femoral cartilage (HC) were similar among groups, while T2 values of the RT following MACT (46.8ms, SD 8.6) were significantly lower when compared to RT T2 values after OCT (55.5ms, SD 6.7) (P=0.048). MACT values were also significantly lower in comparison to HC (52.5ms, SD 7.9) within MACT patients (P=0.046), while OCT values were significantly higher compared to HC (49.9ms, SD 5.1) within OCT patients (P=0.041). The clinical outcome following MACT was consistently superior to that after OCT while only the Lysholm score reached the level of significance (MACT 77.0, OCT 66.8; P=0.04). CONCLUSION: These findings indicate that MACT and OCT result in a different ultrastructural outcome, which is only partially represented by the clinical picture.

[Rotator cuff tears and internal impingement in athletes]. / Rotatorenmanschettendefekte und inneres Impingement beim Sportler.

Knowledge of rotator cuff tears, especially in young people, and their cause has been vastly expanded in recent years. This is reflected in the understanding of the pathogenesis of these lesions and the specific therapy. In contrast to the mostly degenerative tears in older people, the causes in young, active people differ: traumatic disruption, internal impingement due to instability (PSI, ASI), SLAP lesion, and microtraumatic causes may be found. Recently, connections between the different pathologies like internal impingement and the SLAP lesion were shown. For an accurate diagnosis and differentiation between the different pathologies an exact clinical examination and a high-quality MRI scan with intra-articular contrast enhancer is necessary. The final therapy should be planned based on the causative pathology; then good long-term results will be achieved and return to sports is likely. If there is no structural damage, conservative therapy should be initiated. If there is any structural damage, e.g., SLAP lesion or rotator cuff tear, surgical treatment is indicated. Besides a SLAP repair and rotator cuff suturing, care must be given not to miss an accompanying instability. These instabilities should also be corrected, e.g., with arthroscopic ventral capsular plication, otherwise results are worse.

Effects of cefuroxime on human osteoblasts in vitro.

The local application of antibiotics in bone cement achieves high local effective antibiotic concentrations. Cefuroxime is widely used for antibiotic prophylaxis in orthopedic surgery, and several reports highlighted a beneficial outcome if cefuroxime-impregnated bone cement was used, but there is a lack of information of direct cefuroxime effects on human bone cells. We, therefore, cultured osteoblasts, previously derived from human trabecular bone specimens and used as a cell-pool further on, with different concentrations of cefuroxime (0-1000 microg/mL) for 24, 48, or 72 h. For reversibility testing, osteoblasts were cultivated for 24 h with cefuroxime followed by 48 h without antibiotics. Cell proliferation (MTT), cytotoxicity (lactate dehydrogenase (LDH)-activity), cell metabolism (alkaline phosphatase (ALP)-activity), and extracellular matrix calcification (Alizarin staining) were assessed after antibiotic treatment. Cefuroxime concentrations of 25-100 microg/mL had little or no effect on cellular proliferation. Proliferation was significantly stimulated at 250 and 1000 microg/mL at each time. LDH-activity significantly increased at the highest concentration of 1000 microg/mL at 72 h. ALP-activity first increased at lower concentrations and then significantly decreased at 1000 microg/mL at 48 and 72 h. Similar to ALP-activity, calcification increased at lower concentrations and was not detectable at 1000 microg/mL. All revealed effects at 24 h were at least partially reversible. In the present study, we demonstrated that cefuroxime at lower concentrations had no inhibiting effects on human osteoblasts. In contrast, higher concentrations significantly altered osteoblastic function. When administered locally in total joint arthroplasty, for example, in antibiotic-impregnated bone cement, cefuroxime might critically impair osteoblastic function and periprosthetic bone metabolism.

Inducible nonviral gene expression in the treatment of osteochondral defects.

OBJECTIVE: The repair of osteochondral defects with chondrocytes genetically modified to express desired growth factors promises great potential in orthopaedic therapy. Controlled expression of the transgenes is required in many instances. The objective of the present study was to demonstrate the inducibility of tetracycline-responsive transgene expression in osteochondral defects in the knee joint filled with genetically modified chondrocyte implants. METHODS: An expression plasmid containing the lacZ gene under the control of the minimal CMV promoter fused to the Tet-responsible element (TRE) as well as the reverse transactivator (rtTA2s-M2) was constructed and used to transfect isolated articular chondrocytes from New Zealand white rabbits. rtTA2s-M2 binds to the TRE in the presence of tetracycline and leads to the transcription of the transgene. Different concentrations of DNA and various DNA:lipid ratios were tested to determine best transfection conditions. Transfection efficiency and inducibility were analysed by histochemical analysis and flow-cytometry. To evaluate the system in vivo, collagen-sponges were seeded with transfected autologous chondrocytes and implanted in osteochondral defects in the knees of NZW-rabbits. Gene expression was induced by doxycycline and 3 weeks later, LacZ-expression in isolated knee joints was evaluated in histological sections by X-gal staining. RESULTS: In vitro 13.5% (+/-1.32) of induced primary chondrocytes were LacZ-positive, while non-induced controls showed a background-staining in 0.6% (+/-0.2). In vivo, upon doxycycline treatment, induction of lacZ-gene-expression could be demonstrated in chondrocytes in 3-week-old, well-integrated implants. CONCLUSION: For the first time, tetracycline-inducible gene expression is demonstrated to work in the treatment of osteochondral defects. This demonstrates the feasibility for a gene therapy-assisted approach using controlled expression of therapeutic growth factors from transplanted genetically modified chondrocytes.