Reconstruction of medial meniscus posterior portion deficiency in pigs with an autologous patellar tendon graft: an experimental study.

OBJECTIVE: This study was performed to investigate the effectiveness of two surgical procedures, autologous patellar tendon graft reconstruction and trans-tibial plateau pull-out repair, using a pig model. The primary focus was to assess the repair capability of medial meniscus posterior portion (MMPP) deficiency, the overall structural integrity of the meniscus, and protection of the femoral and tibial cartilage between the two surgical groups. The overall aim was to provide experimental guidelines for clinical research using these findings. METHODS: Twelve pigs were selected to establish a model of injury to the MMPP 10 mm from the insertion point of the tibial plateau. They were randomly divided into three groups of four animals each: reconstruction (autologous tendon graft reconstruction of the MMPP), pull-out repair (suture repair of the MMPP via a trans-tibial plateau bone tunnel), and control (use of a normal medial meniscus as the negative control). The animals were euthanized 12 weeks postoperatively for evaluation of the meniscus, assessment of tendon bone healing, and gross observation of knee joint cartilage. The tibial and femoral cartilage injuries were evaluated using the International Society for Cartilage Repair (ICRS) grade and Mankin score. Histological and immunohistochemical staining was conducted on the meniscus-tendon junction area, primary meniscus, and tendons. The Ishida score was used to evaluate the regenerated meniscus in the reconstruction group. Magnetic resonance imaging (MRI) was used to evaluate meniscal healing. RESULTS: All 12 pigs recovered well after surgery; all incisions healed without infection, and no obvious complications occurred. Gross observation revealed superior results in the reconstruction and pull-out repair groups compared with the control group. In the tibial cartilage, the reconstruction group had ICRS grade I injury whereas the pull-out repair and control groups had ICRS grade II and III injury, respectively. The Mankin score was significantly different between the reconstruction and control groups; histological staining showed that the structure of the regenerated meniscus in the reconstruction group was similar to that of the original meniscus. Immunohistochemical staining showed that the degree of type I and II collagen staining was similar between the regenerated meniscus and the original meniscus in the reconstruction group. The Ishida score was not significantly different between the regenerated meniscus and the normal primary meniscus in the reconstruction group. MRI showed that the MMPP in the reconstruction and pull-out repair groups had fully healed, whereas that in the control group had not healed. CONCLUSION: Autologous patellar tendon graft reconstruction of the MMPP can generate a fibrocartilage-like regenerative meniscus. Both reconstruction and pull-out repair can preserve the structural integrity of the meniscus, promote healing of the MMPP, delay meniscal degeneration, and protect the knee cartilage.

Minimally invasive treatment for idiopathic chondrolysis of the hip: analysis of forty-one cases.

PURPOSE: Idiopathic chondrolysis of the hip is characterized by the loss of the articular cartilage of the hip joint with spectrum ranging from full recovery to fibrous ankylosis. Study assessed outcomes following intra-articular steroid injections, joint manipulation and traction immobilization. METHODS: Retrospective (2012-2021) review of 41 cases treated for idiopathic chondrolysis of hip, assessed pre-operatively and post-operatively (minimum 2-year follow-up) using Children's Hospital Oakland Hip Evaluation Score (CHOHES), visual analogue scale (VAS) and range of motion measurements. RESULTS: Twenty-five patients (62%) achieved painless mobility, 6 (14%) had hip stiffness without pain and 10 (24%) had painful and stiff hips at final follow-up. They had a mean age of 12.49 ± 2.4 years and a mean follow-up duration of 33.15 ± 13.1 months. Range of motion improved significantly (p < 0.05). VAS improved to 3.93 ± 1.3 from 7.8 ± 0.7. CHOHES improved from 29.12 ± 9.9 to 56.37 ± 17.6. CONCLUSION: Intra-articular steroid injection, manipulation and traction immobilization may effectively treat idiopathic chondrolysis of the hip by enhancing patient function and reducing the need for further surgical intervention.

Treatment of cartilage defects in the patellofemoral joint with matrix-associated autologous chondrocyte implantation effectively improves pain, function, and radiological outcomes after 5-7 years.

INTRODUCTION: The aim of the present study was to evaluate midterm outcomes 5-7 years after matrix-associated autologous chondrocyte implantation (MACI) in the patellofemoral joint. MATERIALS AND METHODS: Twenty-six patients who had undergone MACI using the Novocart® 3D scaffold were prospectively evaluated. Clinical outcomes were determined by measuring the 36-Item Short-Form Health Survey (SF-36) and International Knee Documentation Committee (IKDC) scores and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) values preoperatively and 3, 6, and 12 months, and a mean of 6 years postoperatively. At the final follow-up, the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score was evaluated. RESULTS: Twenty-two patients with 23 focal cartilage defects (19 patella and four trochlea) were available for the final follow-up. The mean defect size was 4.0 ± 1.9 cm2 (range 2.4-9.4 cm2). All clinical outcome scores improved significantly until 5-7 years after MACI (SF-36 score, 61.2 ± 19.6 to 83.2 ± 11.6; P = 0.001; IKDC score, 47.5 ± 20.6 to 74.7 ± 15.5; P < 0.001; and WOMAC, 29.8 ± 15.7 to 8.2 ± 10.3; P < 0.001). The mean MOCART score was 76.0 ± 11.0 at the final follow-up. Nineteen of the 22 patients (86.4%) were satisfied with the outcomes after 5-7 years and responded that they would undergo the procedure again. CONCLUSION: MACI in the patellofemoral joint demonstrated good midterm clinical results with a significant reduction in pain, improvement in function, and high patient satisfaction. These clinical findings are supported by radiological evidence from MOCART scores. LEVEL OF EVIDENCE: IV-case series.

[Progress on study of factors influencing the prognosis and complications of surgery for discoid meniscus injury in children].

The discoid meniscus is a common congenital meniscal malformation that is prevalent mainly in Asians and often occurs in the lateral discoid meniscus. Patients with asymptomatic discoid meniscus are usually treated by conservative methods such as observation and injury avoidance, while patients with symptoms and tears need to be treated surgically. Arthroscopic saucerization combined with partial meniscectomy and meniscus repair is the most common surgical approach., and early to mid-term reports are good. The prognostic factors are the patient's age at surgery、follow-up time and type of surgery. Some patients experience complications such as prolonged postoperative knee pain, early osteoarthritis, retears and Osteochondritis dissecans. The incidence of prolonged postoperative knee pain was higher and the incidence of Osteochondritis dissecans was the lowest. Retears of the lateral meniscus is the main reason for reoperation.

Atelocollagen-associated autologous chondrocyte implantation for the repair of large cartilage defects of the knee: Results at three to seven years.

BACKGROUND: Recently, various types of engineered autologous chondrocyte implantation (ACI) have been developed. Atelocollagen-associated ACI (A-ACI) is the only ACI procedure covered by Japanese Health Insurance since 2013. The indications of the A-ACI are traumatic cartilage defects and osteochondral dissecans (OCD) for knee joints. PURPOSE: To evaluate midterm clinical results after A-ACI for the treatment for full-thickness cartilage defects of the knee. METHODS: Thirteen consecutive patients who underwent A-ACI between 2014 and 2018 had been prospectively enrolled in this study. There were 11 men and 2 women with a mean age of 34 years at the time of surgery. The causes of the cartilage defect were trauma in 10 knees and OCD in 3 knees. The total number of lesions was 15, which were comprised of the medial femoral condyle in 5 knees, the lateral femoral condyle in 5 knees, and the femoral trochlea in 5 knees. The mean size of the lesion was 5.3 cm2. Each knee was clinically and radiologically evaluated preoperatively and postoperatively. RESULTS: The mean Lysholm score improved significantly from 74.0 points to 94.0 points (p = 0.008) and each subscale in Knee injury and Osteoarthritis Outcome Score improved significantly (p < 0.001) at the mean final follow-up period of 51 months (range, 36-84 months). The magnetic resonance observation of cartilage repair tissue 2.0 score at the mean follow-up of 38 months was significantly higher than that at 2 months postoperatively (p = 0.014). According to the International Cartilage Repair Society (ICRS) grading scale, 3 knees were graded as normal, 3 knees as nearly normal, and 1 knee as severely abnormal in second-look arthroscopic evaluation at a mean of 22 months (range, 8-41 months) after A-ACI. CONCLUSION: The present study showed a significant subjective and objective clinical improvement in the A-ACI for large cartilage defects of the knee at a mean follow-up of 51 months (range, 36-84 months).

Articular Cartilage Injury; Current Status and Future Direction.

Today, treatments of cartilage and osteochondral lesions are routine clinical procedures. The avascular and hard-to-self-repair nature of cartilage tissue has posed a clinical challenge for the replacement and reconstruction of damaged cartilage. Treatment of large articular cartilage defects is technically difficult and complex, often accompanied by failure. Articular cartilage cannot repair itself after injury due to a lack of blood vessels, lymph, and nerves. Various treatments for cartilage regeneration have shown encouraging results, but unfortunately, none have been the perfect solution. New minimally invasive and effective techniques are being developed. The development of tissue engineering technology has created hope for articular cartilage reconstruction. This technology mainly supplies stem cells with various sources of pluripotent and mesenchymal stem cells. This article describes the treatments in detail, including types, grades of cartilage lesions, and immune mechanisms in cartilage injuries.

Arthroscopic and open approaches for autologous matrix-induced chondrogenesis repair of the knee have similar results: a meta-analysis.

BACKGROUND: Cartilage defects are debilitating injuries that can reduce quality of life in patients. However, the poor regenerative properties of cartilage mean that cartilage repair remains challenging, and many methods have arisen to address that. Autologous matrix-induced chondrogenesis (AMIC®) is a popular technique to manage cartilage defects. Recent advances have allowed AMIC® to be done arthroscopically, instead of a mini-open arthrotomy approach. This systematic review and meta-analysis aims to investigate whether the arthroscopic approach to AMIC® provides better clinical outcomes than does the mini-open approach, in hopes of delineating a gold standard in cartilage repair. METHODS: With reference to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, a systematic search of the following databases (PubMed, Embase, Scopus, and Cochrane Library) was performed on 26th October 2022 using a combination of the following search terms: "autologous matrix induced", "chondrogenesis", and "knee". A total of 390 studies were identified, of which, 24 studies were included in our final analysis. RESULTS: The arthroscopic approach achieves lower Visual Analogue Scale for pain scores. The International Knee documentation Committee) score and Knee Injury and Osteoarthritis Outcome Score were comparable between arthroscopic and open approaches. The open approach achieves a higher Magnetic Resonance Observation of Cartilage Repair Tissue score. Incidence of reported postoperative complications of revision surgery and knee stiffness was higher for the open approach than for the arthroscopic approach, whereas deep vein thrombosis was higher in the arthroscopic approach. CONCLUSION: The AMIC® repair outcomes indicate that the arthroscopic approach does not hold a distinct advantage over the open approach. The choice of approach should consider surgeon expertise, location of lesion, and patient-specific factors. LEVEL OF EVIDENCE: Systematic review and meta-analysis; Level III.

Management of chondral and osteochondral lesions of the hip : A comprehensive review.

Chondral and osteochondral lesions encompass several acute or chronic defects of the articular cartilage and/or subchondral bone. These lesions can result from several different diseases and injuries, including osteochondritis dissecans, osteochondral defects, osteochondral fractures, subchondral bone osteonecrosis, and insufficiency fractures. As the cartilage has a low capacity for regeneration and self-repair, these lesions can progress to osteoarthritis. This study provides a comprehensive overview of the subject matter that it covers. PubMed, Scopus and Google Scholar were accessed using the following keywords: "chondral lesions/defects of the femoral head", "chondral/cartilage lesions/defects of the acetabulum", "chondral/cartilage lesions/defects of the hip", "osteochondral lesions of the femoral head", "osteochondral lesions of the acetabulum", "osteochondral lesions of the hip", "osteochondritis dissecans," "early osteoarthritis of the hip," and "early stage avascular necrosis". Hip osteochondral injuries can cause significant damage to the articular surface and diminish the quality of life. It can be difficult to treat such injuries, especially in patients who are young and active. Several methods are used to treat chondral and osteochondral injuries of the hip, such as mesenchymal stem cells and cell-based treatment, surgical repair, and microfractures. Realignment of bony anatomy may also be necessary for optimal outcomes. Despite several treatments being successful, there is a lack of head-to-head comparisons and large sample size studies in the current literature. Additional research will be required to provide appropriate clinical recommendations for treating chondral/osteochondral injuries of the hip joint.

Microfracture of Acetabular Chondral Lesions Is Not Superior to Other Cartilage Repair Techniques in Patients With Femoroacetabular Impingement Syndrome: A Systematic Review.

PURPOSE: To perform a systematic review to compare clinical outcomes of hip arthroscopy patients undergoing microfracture (MFx) versus other cartilage repair procedures for chondral lesions of the acetabulum. METHODS: A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines by searching PubMed, the Cochrane Library, and Embase to identify comparative studies that directly compared outcomes between MFx and other cartilage repair procedures for full-thickness chondral lesions of the acetabulum identified during hip arthroscopy. The search phrase used was: hip AND arthroscopy AND microfracture. Patients were evaluated based on reoperation rates and patient-reported outcomes. RESULTS: Six studies (all Level III evidence) met inclusion criteria, including a total of 202 patients undergoing microfracture (group A) and 327 patients undergoing another cartilage repair procedure (group B). Mean patient age ranged from 35.0 to 45.0 years. Mean follow-up time ranged from 12.0 to 72.0 months. Significantly better patient-reported outcomes (PROs) were found in patients undergoing treatment with bone marrow aspirate concentrate, microfragmented adipose tissue concentrate, autologous matrix-induced chondrogenesis, and a combination of autologous matrix-induced chondrogenesis and bone marrow aspirate concentrate compared with MFx. No studies found significantly better postoperative PROs in group A. The reoperation rate ranged from 0% to 34.6% in group A and 0% to 15.9% in group B. Three of 5 studies reporting on reoperation rate found a significantly greater reoperation rate in group A, with no difference in the other 2 studies. CONCLUSIONS: The literature on MFx of acetabular chondral lesions is limited and heterogeneous. Based on the available data, MFx alone results in a greater or equivalent reoperation rate and inferior or equivalent PROs compared with other cartilage repair procedures for acetabular chondral lesions in patients with femoroacetabular impingement syndrome. LEVEL OF EVIDENCE: Level III, systematic review of level III studies.

Influence of a posteromedial meniscocapsular injury on the knee anterior laxity. A cadaveric study.

PURPOSE: The number of anterior cruciate ligament (ACL) injuries has considerably increased in the recent years, especially in young adults and adolescents. Associated meniscal tears increase anterior and rotary laxity. Posterior peripheral meniscocapsular tear of medial meniscus is also called ramp lesion. Prevalence of 9% to 17% in adults and up to 23% in pediatric population has been reported. The aim of this study was to determine anterior laxity of cadaveric ACL-deficient knees with several size of ramp lesions. METHODS: Fresh cadaveric knees were explored. Major osteoarthritis and/or ACL and meniscal tears on arthroscopy were exclusion criteria. Mean age at death was 86 years old. Dynamic laximetry with GNRB® device was made in several conditions: Knee prior to any procedure, after arthroscopic exploration, after ACL section, and then after increasing sizes of ramp lesions up to 30 mm. Anteroposterior laxity was measured with 2 loading forces successively (134N and 200N). RESULTS: After ACL section only, tibiofemoral joint anterior laxity was significantly increased. Mean increase was 156% regardless of the loading force. No statistical laxity difference was found between knees with ACL section only and knees with ACL and meniscal section for any size of ramp lesions. Increasing size of ramp lesion was not correlated with increasing of laxity. CONCLUSION: We could not find a threshold size of ramp lesion which increases knee anterior laxity. We were not able to determine a threshold recommending a ramp lesion repair.

Positive outcomes following Autologous Matrix-Induced Chondrogenesis (AMIC) in the treatment of retropatellar chondral lesions: a retrospective analysis of a patient registry.

BACKGROUND: The patellofemoral joint is a challenging environment for treating chondral defects. Among the surgical options for the treatment of chondral defects, the single-stage Autologous Matrix-Induced Chondrogenesis (AMIC) procedure uses a porcine collagen I/III membrane to enhance bone-marrow stimulation. However, longer term outcomes data are rare for this specific indication. In order to provide real-world information, an ongoing registry has been established to record patient data and outcomes when AMIC is used to treat chondral and osteochondral lesions. METHODS: Patient data were retrieved from an ongoing, prospective, multisite registry of patients who had undergone AMIC treatment of chondral defects. We identified 64 patients who had undergone AMIC for patellofemoral chondral defects and for whom pre-operative and at least 1 post-operative score were available were included in this retrospective data analysis. Outcomes were assessed via the KOOS, VAS pain, and the Lysholm scores. Outcomes at the post-operative time-points were analysed using a factorial ANOVA with post-hoc testing while linear regression was used to assess associations between the change in the Lysholm score and lesion size. RESULTS: There was a significant improvement in Lysholm, VAS pain, and KOOS scores from pre-operative to the 1st year post-operative (p < 0.001), and this was maintained during the follow-up. CONCLUSIONS: The forces exerted on the patellofemoral joint make this a challenging scenario for chondral repair. Our data demonstrates that the AMIC procedure with a collagen I/III membrane is an effective treatment for retropatellar cartilage lesions, and provides reliable results, with decreased pain and improved function. Importantly, these improvements were maintained through the follow-up period.

Editorial Commentary: Meniscal Extrusion.

With the improved recognition of meniscal root tears over the past decade, it has become clear that root repairs are necessary in most patients indicated for a repair to prevent the further progression of osteoarthritis. Root repairs are cost beneficial to and prevent the early need for a total knee arthroplasty. As further postoperative follow-up occurs for root repairs, we have found that most patients have significantly improved patient-reported outcomes, while it is still clear that further clinical outcome study as well as further refinement of surgical technique is necessary. The next thing that we have to investigate is how to prevent recurrent meniscal extrusion after a root repair. Nonanatomic repair significantly alters tibiofemoral biomechanics and results in notably increased meniscal extrusion. In contrast, biomechanical studies show anatomic repair of the meniscus attachment within 1 cm of the meniscus attachment site restores joint loading close to normal.

Minced Cartilage Implantation in Acetabular Cartilage Defects: Case Series with 2-Year Results.

OBJECTIVE: The objective was to evaluate clinical outcome and safety of arthroscopic, autologous minced cartilage implantation for acetabular cartilage lesions observed during hip arthroscopy to treat femoroacetabular impingement syndrome (FAIS). DESIGN: Eleven male patients, average age: 29.4 ± 5.4 years, average body mass index (BMI): 24.2 ± 2.2 kg/m2, scheduled for hip arthroscopy due to FAIS accompanied by an acetabular cartilage lesion were included in the case series. Cartilage tissue was harvested and minced from the loose cartilage flap at the chondrolabral lesion by arthroscopic shaver, augmented with autologous conditioned plasma, implanted into the defect, and fixated by autologous thrombin. Concomitant interventions were performed as indicated. The patients were evaluated preoperatively and at 24-month follow-up, using the International Hip Outcome Tool-12 (iHOT-12) and Visual Analog Scale (VAS) pain score and by magnetic resonance imaging (MRI) using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) grading scale at the 2-year follow-up. RESULTS: The defect size was on average 3.5 cm2 (1.5-4.5 cm2). From preoperatively to 2 years postoperatively, the iHOT-12 significantly improved from 50.2 ± 18 to 86.5 ± 19 (P < 0.0001), and pain score decreased from 5.6 ± 1.8 to 1.0 ± 1.5 (P < 0.0001) on the Visual Analog Scale pain score. Regarding functional outcome and pain, 10 of the 11 patients and all patients reached the minimal clinically important difference (MCID), respectively. The postoperative average MOCART score was 87.2 (± 9.2). No adverse events or reoperations were observed. CONCLUSIONS: Arthroscopic, autologous minced cartilage implantation for treating full-thickness acetabular cartilage lesions in FAIS shows statistically and clinically significant improvement at short-term follow-up.

The AMADEUS score is not a sufficient predictor for functional outcome after autologous chondrocyte implantation (ACI) of the knee: data from the German Cartilage Registry (KnorpelRegister DGOU).

INTRODUCTION: The AMADEUS (Area Measurement And DEpth and Underlying Structures) score has advanced to a commonly used tool for MRI-based chondral defect severity grading prior to cartilage knee surgery. It was the intention of this study to assess the AMADEUS for a potential correlation with clinical data by patient-reported outcome measures (PROMs). METHODS: A total of 51 patients undergoing ACI (autologous chondrocyte implantation) between 2016 and 2022 were found eligible and retrospectively analyzed. All patients were registered in the German Cartilage Registry prior to surgery and follow-up data were collected using the Knee Osteoarthritis Outcome score (KOOS), the International Knee Documentation Committee (IKDC) Form and the numeric rating scale (NRS). Pre-operative MRI images were scored by three raters using the AMADEUS classification system, and an overall AMADEUS score was calculated which was subsequently correlated with pre- and post-operative PROMs. RESULTS: Mean patient age was 32.67 ± 8.37 years and mean defect size area 343.04 mm2 ± 139.45 mm2. No correlative capacity of the pre- and postoperative IKDC, KOOS or NRS scores was found with the AMADEUS final score or any of its subscores. From the pre- to postoperative visit, a significant improvement of the PROMs (IKDC: 45.53 ± 21.00 vs. 59.83 ± 17.93, p = 0.04; KOOS Pain: 58.00 ± 16.70 vs. 76.06 ± 19.20, p = 0.03; KOOS ADL: 64.17 ± 18.76 vs. 82.11 ± 16.68, p < 0.01; KOOS Sports: 26.11 ± 18.52 vs. 50.56 ± 23.94, p = 0.01; KOOS QOL: 25.50 ± 14.26 ± 45.28 ± 19.03, p = 0.00) was found. Intraclass correlation coefficients showed an overall good interrater agreement for the AMADEUS total score (ICC = 0.75). CONCLUSIONS: Study results suggest no correlative capacity of the AMADEUS with routinely used PROMs in patients undergoing ACI. Therefore, radiographically assessed cartilage defect characteristics poorly translate to pre- and postoperative patient-reported outcome data.

Lateral meniscus with tears or with histologic calcification does not increase the risk of lateral osteoarthritis after medial unicompartmental arthroplasty.

PURPOSE: Meniscal tears or histological meniscal calcifications (in the absence of radiological chondrocalcinosis) are frequent in osteoarthritis. Whether lateral meniscal lesions influence clinical outcomes after medial unicompartmental knee arthroplasty (UKA) is unknown. METHODS: We analyzed 130 patients (130 knees) with medial unicompartmental knee arthroplasties between 2005 and 2015. These 130 knees had full articular cartilage thickness in the lateral compartment and no radiological chondrocalcinosis on preoperative radiographs. The lateral meniscus was analyzed with preoperative MRI and a biopsy of the anterior horn at the time of surgery. Synovial fluid was collected and analyzed for calcium pyrophosphate dihydrate crystal deposition (CPPD crystals). Lateral meniscal tears were untreated when detected on MRI or during surgery, with the hypothesis that these tears on the opposite compartment would remain asymptomatic in medial UKA. At average 10-year follow-up, patients were evaluated with clinical and radiographic outcome, with a focus on the risk of joint space narrowing of the lateral femorotibial compartment. RESULTS: CPPD crystals were present in the synovial fluid of 70 knees. Lateral meniscal tears were seen on MRI in 34 (49%) normal meniscuses of the 60 knees without CPPD crystals and in six other knees without histological meniscal calcification despite CPPD crystals. Histological calcification was present on 61 lateral meniscuses with 53 meniscal tears. The results showed no significant differences in the clinical outcomes between knees with lateral meniscal tears or lateral meniscal histological chondrocalcinosis or both lesions and those without these conditions. Additionally, radiographic progression of osteoarthritis in the opposite femorotibial compartment of the knee was not more frequent in patients with these meniscal issues. The ten year cumulative survival rates, measured by the need for total knee arthroplasty, were 91% for knees without meniscal lesions and 92% for knees with these lesions. CONCLUSION: On this basis, treatment of meniscal tears of the lateral compartment and routine aspiration of the knee to assess for birefringent crystals in the planning of medial UKA do not appear necessary.

The biomechanical and functional outcomes of autologous chondrocyte implantation for articular cartilage defects of the knee: A systematic review.

PURPOSE: Autologous chondrocyte implantation (ACI) is primarily performed in active, young patients to treat knee pain and functional limitations resulting from articular cartilage injury. Nevertheless, the functional outcomes of ACI remain poorly understood. This systematic review aimed to evaluate the biomechanical and functional outcomes of ACI. METHODS: Ovid MEDLINE, Embase, and Web of Science were systematically searched using the terms 'Knee OR Knee joint AND Autologous chondrocyte implantation OR ACI'. Inclusion and exclusion criteria were used to screen publications by title, abstract, and full text. Study quality and bias were assessed by two reviewers. Means and standard deviations of all collected variables were calculated and presented in the review. PROSPERO ID: CRD42021238768. RESULTS: Nineteen articles including 20 ACI cohorts were included. In general, the average range of motion (ROM) improved with clinical (>5°) and statistical significance (p < 0.05) postoperatively: 130.5 ± 14.8° to 136.1 ± 10.2°. Knee strength significantly improved within the first two postoperative years but remained poorer than control groups at final follow-up. No statistical differences were found between ACI and control groups in their ability to perform functional activities like the 6-minute walk test. CONCLUSION: Knee range of motion generally improved following ACI. Although, some studies reported that knee strengths remained significantly poorer than healthy controls, particularly >2-years postoperatively, implying that longer-term strength training may benefit patients.However, the volume of research and current level of evidence remain low, thus further research is required to better understand the impact of ACI on knee function and guide future rehabilitative protocols.

Single-step ultra-purified alginate gel implantation in patients with knee chondral defects.

Aims: Implantation of ultra-purified alginate (UPAL) gel is safe and effective in animal osteochondral defect models. This study aimed to examine the applicability of UPAL gel implantation to acellular therapy in humans with cartilage injury. Methods: A total of 12 patients (12 knees) with symptomatic, post-traumatic, full-thickness cartilage lesions (1.0 to 4.0 cm2) were included in this study. UPAL gel was implanted into chondral defects after performing bone marrow stimulation technique, and assessed for up to three years postoperatively. The primary outcomes were the feasibility and safety of the procedure. The secondary outcomes were self-assessed clinical scores, arthroscopic scores, tissue biopsies, and MRI-based estimations. Results: No obvious adverse events related to UPAL gel implantation were observed. Self-assessed clinical scores, including pain, symptoms, activities of daily living, sports activity, and quality of life, were improved significantly at three years after surgery. Defect filling was confirmed using second-look arthroscopy at 72 weeks. Significantly improved MRI scores were observed from 12 to 144 weeks postoperatively. Histological examination of biopsy specimens obtained at 72 weeks after implantation revealed an extracellular matrix rich in glycosaminoglycan and type II collagen in the reparative tissue. Histological assessment yielded a mean overall International Cartilage Regeneration & Joint Preservation Society II score of 69.1 points (SD 10.4; 50 to 80). Conclusion: This study provides evidence supporting the safety of acellular UPAL gel implantation in facilitating cartilage repair. Despite being a single-arm study, it demonstrated the efficacy of UPAL gel implantation, suggesting it is an easy-to-use, one-step method of cartilage tissue repair circumventing the need to harvest donor cells.

Clinical evaluation of a resurfacing device implant for femoral osteochondral defects greater than 1 cm2 with a minimal follow-up of 4 years: a prospective cohort study.

PURPOSE: Osteochondral defects have a limited capacity to heal and can evolve to an early osteoarthritis. A surgical possibility is the replacement of the affected cartilaginous area with a resurfacing device BioPoly™ RS Partial Resurfacing Knee Implant. The aim of this study was to report the clinical and survival outcomes of the BioPoly™ after a minimum follow-up of 4 years. METHODS: This study included all patients who had a BioPoly™ for femoral osteochondral defects greater than 1 cm2 and at least ICRS grade 2. The main outcome was to observe the KOOS and the Tegner activity score were used to assess outcomes preoperatively and at the last follow-up. The secondary outcomes were the VAS for pain, the complications rate post-surgery and survival rate of BioPoly™ at the last FU. RESULTS: Eighteen patients with 44.4% (8/18) of women were included with a mean age of 46.6 years (11.4), a mean body mass index (BMI) of 21.5 (kg/m2) (2.3). The mean follow-up was 6.3 years (1.3). We found a significant difference comparing pre-operative KOOS score and at last follow-up [respectively, 66.56(14.37) vs 84.17(7.656), p < 0.01]. At last follow-up, the Tegner score was different [respectively, 3.05(1.3) vs 3.6(1.3), p < 0.01]. At 5 years, the survival rate was of 94.7%. CONCLUSIONS: BioPoly™ is a real alternative for femoral osteochondral defects greater than 1 cm2 and at least ICRS grade 2. It will be interesting to compare this implant to mosaicplasty technic and/or microfracture at 5 years postoperatively regarding clinical outcomes and survival rate. LEVEL OF EVIDENCE: Therapeutic level III. Prospective cohort study.

[The first decade of the DGOU's cartilage register-insights for clinical practice]. / Die erste Dekade des KnorpelRegisters der DGOU ­ Erkenntnisse für die klinische Praxis.

BACKGROUND: Registry data provide valuable epidemiological insights that help to further improve process and outcome quality in patient care. The German Cartilage Registry (KnorpelRegister DGOU) was established in 2013 as an instrument for quality assurance after surgical cartilage regenerative procedures on hip, knee and ankle joints. DATA COLLECTION: Participation in the German Cartilage Registry is optional for hospitals and practices. Currently, more than 160 institutions in Germany, Austria and Switzerland participate in the data collection. DATA COLLECTED AND INITIAL FINDINGS: The implementation of PROMs ("patient related outcome measurement"), as well as the recording of surgery-related influencing factors, enable a differentiated scientific analysis and represent a key quality feature of the registry. Initial analyses of the registry data have already provided clinically relevant findings for immediate patient care. For example, patients who underwent focal cartilage therapy prior to ACT show a clinically relevant, significantly worse outcome than patients who underwent primary ACT. First conclusions could also be drawn regarding the relevance of concomitant cartilage therapy. For example, in patients with focal cartilage damage of the medial knee joint compartment, registry data indicate that leg axis correction is indicated even in cases of mild deviation of the mechanical leg axis. CONCLUSION: The data and findings obtained from the Cartilage Registry represent an important aspect of clinical care research and serve as a complement to well-designed, clinically prospective cohort studies, RCTs, and meta-analyses.