Plantaris Tendon Autograft Can Restore Patellar Stability in Adolescent Medial Patellofemoral Ligament Reconstruction: A Technical Note.

Medial patellofemoral ligament reconstruction is a standard treatment option for patients with patellar instability. The main purpose of this study was to determine whether isolated anatomic medial patellofemoral ligament reconstruction using double folded, four-strand plantaris tendon autograft restores patellar stability in adolescent patients. Plantaris tendon autografts were harvested through proximal approach and used in four adolescent patients. A four-strand autograft was prepared in a double-limbed configuration and fixed on the patella and the femur with suture anchors and interference screws, respectively. The mean Kujala score improved significantly from 44 ± 24 SD (range, 19 to 69) points preoperatively to 94 ± 10 SD (range, 78 to 100) points postoperatively (P< 0.001). All patients reported excellent subjective outcomes and returned to their pre-injury level of sporting activities. The use of a four-strand plantaris tendon autograft in isolated anatomic medial patellofemoral ligament reconstruction can restore patellar stability in adolescents.

Management of the first episode of traumatic patellar dislocation: an international survey.

PURPOSE: This international survey aimed to evaluate the potential controversies regarding the management of first patellar dislocation amongst experienced knee surgeries in the treatment of the first episode of patellar dislocation without osteochondral fragments. METHODS: An online survey was conducted from February 2021 to December 2021 to assess the global trend in the diagnosis and management of first-time patellar dislocation without osteochondral fragments. The online survey was accessible on the homepage of the website of the European Society of Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA). The questionnaire consisted of multiple-choice questions and was divided into three sections. The first section consisted of eight questions regarding demographic information, professional activity, and responder experience. The second section consisted of 13 questions regarding the approach to a first patellar dislocation (clinical examination, imaging, and rehabilitation). The third section contained 2 questions concerning the relevance of patient characteristics to the therapeutic algorithm (age, sports, and pathoanatomical predisposing risk factors). RESULTS: A total of 438 orthopaedic surgeons worldwide completed the questionnaire. At the first approach to diagnose a first-time patellar dislocation, 251 (57%) of the surgeons requested plain radiographs, and 158 (36%) requested magnetic resonance imaging (MRI). In conservatively treated patients, 368 (84%) of the respondents recommended the use of a knee brace. Amongst them, 14 (3%) advocated its use for one week, 75 (17%) for two weeks, 123 (28%) for three weeks, 105 (24%) for four weeks, and 97 (22%) for six weeks. In conservatively treated patients, 215 (49%) of the surgeons recommended load to tolerance, 148 (34%) recommended 30% to 60% of the bodyweight, and 75 (17%) advised against weight-bearing. More than half of the surgeons considered a patient aged less than 35 years practising contact sports to be a candidate for the medial patello-femoral ligament (MPFL) procedure. In addition, a tibial tuberosity to trochlear groove distance (TT-TG) distance of 15 to > 20 mm (for > 75% of the surgeons) and a trochlea types C and D (for > 70% of the surgeons) were considered possible indications for direct surgical management. CONCLUSION: At the first approach to diagnose a first-time patellar dislocation, plain radiographs and MRI should be performed. In conservatively treated patients, most of the surgeons recommend weight-bearing to tolerance and a knee brace during the first four weeks, with range of motion of full extension to 30° during the first 15 days and up to 60° for an additional 15 days. Surgical management should be performed in patients in the second and third decades of life practising contact sports and in those patients who present types C and D trochlea dysplasia and patella alta. LEVEL OF EVIDENCE: IV.

Reciprocal Alterations in Osteoprogenitor and Immune Cell Populations in Rheumatoid Synovia.

Rheumatoid arthritis (RA) is chronic, autoimmune joint inflammation characterized by irreversible joint destruction. Besides increased resorption, destruction is a result of decreased bone formation, due to suppressed differentiation and function of the mesenchymal lineage-derived osteoblasts in inflammatory milieu. In this study, we analyzed the cellular composition of synovial tissue from 11 RA and 10 control patients harvested during planned surgeries in order to characterize resident synovial progenitor populations. Synovial cells were released by collagenase, and labeled for flow cytometry by two antibody panels: 1. CD3-FITC, CD14-PE, 7-AAD, CD11b-PECy7, CD235a-APC, CD19-APCeF780; and 2. 7-AAD, CD105-PECy7, CD45/CD31/CD235a-APC, and CD200-APCeF780. The proportions of lymphocytes (CD3+, CD19+) and myeloid (CD11b+, CD14+) cells were higher in synovial tissue from the patients with RA than in the controls. Among non-hematopoietic (CD45-CD31-CD235a-) cells, there was a decrease in the proportion of CD200+CD105- and increase in the proportion of CD200-CD105+ cells in synovial tissue from the patients with RA in comparison to the control patients. The proportions of both populations were associated with inflammatory activity and could discriminate between the RA and the controls.

Plantaris tendon is valuable graft for the medial patellofemoral ligament reconstruction: A biomechanical study.

BACKGROUND: Medial patellofemoral ligament (MPFL) reconstruction is a standard treatment option for selected patients with patellar instability. Although frequently performed, the optimal graft source for the procedure has not yet been established. This study aimed to determine whether a two-strand plantaris tendon construct possesses the biomechanical properties needed to act as an MPFL reconstruction graft. METHODS: Thirty paired plantaris and gracilis tendons were harvested from 15 cadavers, mean age at death of 42.7 years. All specimens were frozen and maintained at -20 °C until biomechanical testing. Prior to mechanical testing, specimens were thawed at room temperature. The two-strand plantaris tendon and two-strand gracilis tendon constructs were created and secured in a uniaxial tensile testing machine in a triangular-shaped mode. Biomechanical properties for tensile testing to failure were determined using validated method. Results obtained were compared with the previously published data on native MPFL biomechanical properties. RESULTS: The mean maximal force was 220.3 ± 108.1 N and 448.1 ± 117 N for the two-strand plantaris tendon construct and two-strand gracilis tendon construct, respectively. Significant differences were observed between all biomechanical properties of two-strand plantaris tendon and two-strand gracilis tendon constructs. The mean maximal force of a two-strand plantaris tendon construct and a two-strand gracilis tendon construct were greater than the mean maximal force of the native MPFL reported in all previous studies. CONCLUSIONS: This study suggests that, due to its biomechanical properties, the two-strand plantaris tendon graft is suitable as a graft for MPFL reconstruction.

Comparison of systemic inflammatory responses of proximal femoral nail versus dynamic hip screw after treatment of patients with pertrochanteric fractures: A prospective comparative study.

OBJECTIVE: The aim of this study was to investigate the differences between the induction of early postoperative inflammatory response and muscle tissue injury biomarkers after treatment of pertrochanteric fractures by dynamic hip screw (DHS) or proximal femoral nail (PFN). METHODS: In this prospective comparative study, 40 patients with AO-Müller/Orthopaedic Trauma Association (AO/OTA) 31. A1-31.A2 pertrochanteric fractures were enrolled and allocated one of the two groups based on the treatment type: group DHS, (n =20,mean age = 78.4 ± 6.9 years) and group PFN (n = 20, mean age = 77.75 ± 7.0 years). Operation time was recorded in both groups. In each patient, circulating levels of high sensitivity interleukin-6 (hs-IL-6), C-reactive protein (CRP), and creatine kinase (CK), and erythrocyte sedimentation rate (ESR)weremeasured fromblood samples collected 1 hour preoperatively and 24 hours postoperatively. RESULTS: The operation time was slightly shorter in group PFN than in group DHS (51.9 ± 21.1 and 38 ± 15.2 min, respectively; P = 0.02). DHS and PFN both increased hs-IL-6 (143.81 ± 89.12 and 94.13 ± 67.14, respectively), CRP (98.84 ± 31.81 and 104.4 ± 31.80, respectively), and CK (400.8 ± 31.81 and 250.7 ± 31.80, respectively) 24 hours postoperatively. However, PFN compared to DHS resulted in a lesser increase from baseline to 24 hours postoperatively only in hs IL-6 (58.91 ± 59.02 vs 113.30 ± 76.24, respectively; P = 0.0016) and CK (163.6 ± 123.3 vs 310.0 ± 198.3, respectively; P < 0.0001).Moreover, there was a positive correlation of CK levels' surgery time in DHS (r = 0.38, P = 0.0065) and PFN (r = 0.45, P = 0.0013). CONCLUSION: The results of this study have shown that PFN can induce a lower early postoperative inflammatory response and muscle tissue injury based on the assessment of hs-IL-6 and CK levels, compared to DHS in after the treatment patients pertrochanteric fractures. LEVEL OF EVIDENCE: Level II, Therapeutic Study.

Tibial tuberosity-tibial intercondylar midpoint distance measured on computed tomography scanner is not biased during knee rotation and could be clinically more relevant than current measurement systems.

PURPOSE: The purpose of this retrospective cross-sectional case-control study was to evaluate an alternative imaging test for lateralization of the tibial tuberosity, unbiased towards knee rotation. METHODS: On axial CT images of 129 knees, classified as cases (two or more patellar luxations) and controls (no patellar luxations), two raters gauged the standard tibial tuberosity-trochlear groove (TT-TG) distance, tibial tuberosity-femoral intercondylar midpoint (TT-FIM) distance, and new tibial tuberosity-tibial intercondylar midpoint (TT-TIM) distance singly, and knee longitudinal rotation angles (LRAs), and the presence of femoral trochlear dysplasia (FTD) jointly. RESULTS: All imaging tests intercorrelated and discriminated between stability groups. TT-TIM had the lowest values with the highest precision. Though poorly, TT-TG and TT-FIM negatively correlated with age and LRAs regarding femur, but positively with presence of FTD, whereas TT-TIM was unbiased. The accuracy of TT-TG (> 20 mm), TT-FIM (> 20 mm), and TT-TIM (> 13 mm) was good with almost perfect reproducibility. Only TT-TIM was sex-biased (p = 0.009), with > 12 mm cut-off in females and (presumably) > 14 mm in males. CONCLUSION: TT-TIM is an alternative imaging test for lateralization of the tibial tuberosity, unbiased towards knee rotation.

Plantaris tendon: a novel graft for anterolateral ligament reconstruction and additional reinforcement for anterior cruciate ligament autografts in combined reconstructive procedures.

The anterolateral ligament is recently recognized as an important structure in restoring rotational stability of the anterior cruciate ligament-deficient knee. Biomechanical and clinical studies confirmed the benefits of concurrent anterior cruciate ligament and anterolateral ligament reconstruction. However, present techniques mostly use hamstring tendons autografts and therefore additionally disrupt the knee biomechanics. The plantaris tendon is a well known and accessible graft and has excellent biomechanical properties for anterolateral ligament reconstruction. The present paper describes a new combined anterior cruciate ligament and anterolateral ligament reconstruction technique using plantaris tendon and semitendinosus tendon.Level of evidence V (Case report).

Applications and critical evaluation of fascia iliaca compartment block and quadratus lumborum block for orthopedic procedures.

Anterior section of the hip joint capsule is innervated by femoral nerve and obturator nerve, and posterior section is innervated by the nerve to quadratus femoris muscle and occasionally by the superior gluteal (posterolateral region) and sciatic nerve (posterosuperior region). One of the regional anesthesia options for hip surgery is the fascia iliaca compartment block (FICB) that affects nerves important for hip innervation and sensory innervation of the thigh - femoral, obturator and lateral femoral cutaneous nerve. FICB can be easily performed and is often a good solution for management of hip fractures in emergency departments. Its use reduces morphine pre-operative requirement for patients with femoral neck fractures and can also be indicated for hip arthroplasty, hip arthroscopy and burn management of the region. Quadratus lumborum block (QLB) is a block of the posterior abdominal wall performed exclusively under ultrasound guidance, with still unclarified mechanism of action. When considering hip surgery and postoperative management, the anterior QLB has shown to reduce lengthy hospital stay and opioid use, it improves perioperative analgesia in patients undergoing hip and proximal femoral surgery compared to standard intravenous analgesia regimen, provides early and rapid pain relief and allows early ambulation, thus preventing deep vein thrombosis and thromboembolic complications etc. However, some nerve branches responsible for innervation of the hip joint are not affected by QLB, which has to be taken into consideration. QLB has shown potential for use in hip surgery and perioperative pain management, but still needs to be validated as a reliable treatment approach.

The plantaris muscle: too important to be forgotten. A review of evolution, anatomy, clinical implications and biomechanical properties.

Plantaris muscle (lat. musculus plantaris) is a fusiform muscle of the superficial posterior leg compartment, characterized with a small muscle belly and very long and slender tendon. Many anatomical variations of plantaris muscle have been reported previously, including its inconstancy. Evolutional studies strongly suggest that plantaris muscle is a rudimentary muscle that plays minor role in gait biomechanics. However, plantaris muscle seems to have very important proprioceptive role since it has very high density of muscle spindles. Clinically, plantaris muscle is involved in differential diagnosis of posterior leg pain and several pathological entities such as: plantaris muscle rupture, non-insertional Achilles tendinopathy and popliteal artery compression syndrome. Different surgical specialties have recognized plantaris muscle tendon as a valuable graft. However, literature on plantaris muscle tendon biomechanical properties is rather scant and inconsistent with several limitations for proper data comparison and interpretation. Further comparative studies are needed to properly define biomechanical properties of plantaris muscle tendon grafts for various ligament and tendon reconstructive procedures.

The physiological range of the Böhler's angle in the adult Croatian population.

BACKGROUND: To examine the relationship of the Böhler's angle with age, sex, and laterality, and to analyze the interrater agreement. METHODS: After 248 digital lateral radiographs of the foot were submitted to exclusion criteria, three raters independently measured the Böhler's angle on the remaining 130 X-rays in PACS. The variables were analyzed with correlation coefficients, and one-way ANOVA. The repeated measures of ANOVA were computed across age groups (30-39, 40-49, 50-59, and 60-69 years). The interrater agreement was calculated using intraclass correlation coefficient (ICC). RESULTS: The mean value of the Böhler's angle was 34±5° (21-46°). It was not related to age (in general [p=0.057], and across groups [p from 0.107 to 0.122]), sex (p=0.344; p=0.342), and laterality (p=0.618; p=0.617). The interrater reliability was almost perfect (ICC=0.94). CONCLUSIONS: The Böhler's angle was not related to age, sex, and laterality, whereas the interrater agreement was almost perfect.

Biological aspects of segmental bone defects management.

Segmental bone defect management is among the most demanding issues in orthopaedics and there is a great medical need for establishing an appropriate treatment option. Tissue transfer, including bone autografts or free flaps, depending on the size of the bone deficiency, is currently the "gold standard" for treatment of such defects. Osteogenic cells in combination with adequate growth factors and a suitable scaffold, from the aspect of osteoinductivity, osteoconductivity and mechanical stability, are mandatory to successfully restore a bone defect as determined in the "diamond concept". Our current knowledge on this topic is limited and mostly based on retrospective studies, case reports and a few small randomised clinical trials due to the lack of large and accurately designed randomised clinical trials using novel approaches to regenerative orthopaedics. However, preclinical research on different animal models for critical size defects is abundant, showing emerging candidate cells and cytokines for defect rebridgement. In this article we provide an overview on existing clinical studies and promising preclinical experiments that utilised osteogenic cells, growth factors and biomaterials, as well as their combination for repair of segmental bone defects.

The clinical use of bone morphogenetic proteins revisited: a novel biocompatible carrier device OSTEOGROW for bone healing.

PURPOSE: The purpose of this study was to revise the clinical use of commercial BMP2 (Infuse) and BMP7 (Osigraft) based bone devices and explore the mechanism of action and efficacy of low BMP6 doses in a novel whole blood biocompatible device OSTEOGROW. METHODS: Complications from the clinical use of BMP2 and BMP7 have been systemically reviewed in light of their role in bone remodeling. BMP6 function has been assessed in Bmp6-/- mice by µCT and skeletal histology, and has also been examined in mesenchymal stem cells (MSC), hematopoietic stem cells (HSC) and osteoclasts. Safety and efficacy of OSTEOGROW have been assessed in rats and rabbits. RESULTS: Clinical use issues of BMP2 and BMP7 have been ascribed to the limited understanding of their role in bone remodeling at the time of device development for clinical trials. BMP2 and BMP7 in bone devices significantly promote bone resorption leading to osteolysis at the endosteal surfaces, while in parallel stimulating exuberant bone formation in surrounding tissues. Unbound BMP2 and BMP7 in bone devices precipitate on the bovine collagen and cause inflammation and swelling. OSTEOGROW required small amounts of BMP6, applied in a biocompatible blood coagulum carrier, for stimulating differentiation of MSCs and accelerated healing of critical size bone defects in animals, without bone resorption and inflammation. BMP6 decreased the number of osteoclasts derived from HSC, while BMP2 and BMP7 increased their number. CONCLUSIONS: Current issues and challenges with commercial bone devices may be resolved by using novel BMP6 biocompatible device OSTEOGROW, which will be clinically tested in metaphyseal bone fractures, compartments where BMP2 and BMP7 have not been effective.

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

PURPOSE: The aim of this systematic review is to examine the available clinical evidence in the literature to support mesenchymal stem cell (MSC) treatment strategies in orthopaedics for cartilage defect regeneration. METHODS: The research was performed on the PubMed database considering the English literature from 2002 and using the following key words: cartilage, cartilage repair, mesenchymal stem cells, MSCs, bone marrow concentrate (BMC), bone marrow-derived mesenchymal stem cells, bone marrow stromal cells, adipose-derived mesenchymal stem cells, and synovial-derived mesenchymal stem cells. RESULTS: The systematic research showed an increasing number of published studies on this topic over time and identified 72 preclinical papers and 18 clinical trials. Among the 18 clinical trials identified focusing on cartilage regeneration, none were randomized, five were comparative, six were case series, and seven were case reports; two concerned the use of adipose-derived MSCs, five the use of BMC, and 11 the use of bone marrow-derived MSCs, with preliminary interesting findings ranging from focal chondral defects to articular osteoarthritis degeneration. CONCLUSIONS: Despite the growing interest in this biological approach for cartilage regeneration, knowledge on this topic is still preliminary, as shown by the prevalence of preclinical studies and the presence of low-quality clinical studies. Many aspects have to be optimized, and randomized controlled trials are needed to support the potential of this biological treatment for cartilage repair and to evaluate advantages and disadvantages with respect to the available treatments. LEVEL OF EVIDENCE: IV.

[Ligament which deserves attention--medial patellofemoral ligament]. / Ligament koji zasluzuje pozornost--medijalni patelofemoralni ligament.

There has been increasing interest in investigating the medial patellofemoral ligament (MPFL) during the last fifteen years. This is due to the recognition of the MPFL as the primary static soft-tissue restraint to lateral patellar displacement and the association of MPFL injury with primary traumatic patellar dislocation. The MPFL often heals poorly and thus rarely regains its full function. Numerous surgical techniques have been described for reconstruction of this important structure. This paper reviews the relevant anatomy and biomechanics, published reconstruction options, and describes the surgical technique performed at our institution--that of using a quadriceps autograft to reconstruct the MPFL.

Non-surgical management of early knee osteoarthritis.

Conservative approach is usually the first choice for the management of the knee degeneration processes, especially in the phase of the disease recognized as early osteoarthritis (OA) with no clear lesions or associated abnormalities requiring to be addressed surgically. A wide spectrum of treatments is available, from non-pharmacological modalities to dietary supplements and pharmacological therapies, as well as minimally invasive procedures involving injections of various substances aiming to restore joint homeostasis and provide clinical improvement and possibly a disease-modifying effect. Numerous pharmaceuticals have been proposed, but since no therapy has shown all the characteristic of an ideal treatment, and side effects have been reported at both systemic and local level, the use of pharmacological agents should be considered with caution by assessing the risk/benefit ratio of the drugs prescribed. Both patients and physicians should have realistic outcome goals in pharmacological treatment, which should be considered together with other conservative measures. A combination of these therapeutic options is a more preferable scenario, in particular considering the evidence available for non-pharmacological management. In fact, exercise is an effective conservative approach, even if long-term effectiveness and optimal dose and administration modalities still need to be clarified. Finally, physical therapies are emerging as viable treatment options, and novel biological approaches are under study. Further studies to increase the limited medical evidence on conservative treatments, optimizing results, application modalities, indications, and focusing on early OA will be necessary in the future. Level of evidence IV.

Bone morphogenetic protein (BMP)1-3 enhances bone repair.

Members of the astacin family of metalloproteinases such as human bone morphogenetic protein 1 (BMP-1) regulate morphogenesis by processing precursors to mature functional extracellular matrix (ECM) proteins and several growth factors including TGFß, BMP2, BMP4 and GFD8. We have recently discovered that BMP1-3 isoform of the Bmp-1 gene circulates in the human plasma and is significantly increased in patients with acute bone fracture. We hypothesized that circulating BMP1-3 might have an important role in bone repair and serve as a novel bone biomarker. When administered systemically to rats with a long bone fracture and locally to rabbits with a critical size defect of the ulna, recombinant human BMP1-3 enhanced bone healing. In contrast, neutralization of the endogenous BMP1-3 by a specific polyclonal antibody delayed the bone union. Invitro BMP1-3 increased the expression of collagen type I and osteocalcin in MC3T3-E(1) osteoblast like cells, and enhanced the formation of mineralized bone nodules from bone marrow mesenchymal stem cells. We suggest that BMP1-3 is a novel systemic regulator of bone repair.

Characterized chondrocyte implantation results in better structural repair when treating symptomatic cartilage defects of the knee in a randomized controlled trial versus microfracture.

BACKGROUND: As the natural healing capacity of damaged articular cartilage is poor, joint surface injuries are a prime target for regenerative medicine. Characterized chondrocyte implantation uses an autologous cartilage cell therapy product that has been optimized for its biological potency to form stable cartilage tissue in vivo. PURPOSE: To determine whether, in symptomatic cartilage defects of the femoral condyle, structural regeneration with characterized chondrocyte implantation is superior to repair with microfracture. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: Characterized chondrocyte implantation was compared with microfracture in patients with single grade III to IV symptomatic cartilage defects of the femoral condyles in a multicenter trial. Patients aged 18 to 50 years were randomized to characterized chondrocyte implantation (n = 57) or microfracture (n = 61). Structural repair was blindly assessed in biopsy specimens taken at 1 year using (1) computerized histomorphometry and (2) evaluation of overall histological components of structural repair. Clinical outcome was measured using the self administered Knee injury and Osteoarthritis Outcome Score. Adverse events were recorded throughout the study. RESULTS: Characterized chondrocyte implantation resulted in better structural repair, as assessed by histomorphometry (P = .003) and overall histologic evaluation (P = .012). Aspects of structural repair relating to chondrocyte phenotype and tissue structure were superior with characterized chondrocyte implantation. Clinical outcome as measured by the Knee injury and Osteoarthritis Outcome Score at 12 to 18 months after characterized chondrocyte implantation was comparable with microfracture at this stage. Both treatment groups had a similar mean baseline overall Knee injury and Osteoarthritis Outcome Score (56.30 +/- 13.61 and 59.53 +/- 14.95 for microfracture and characterized chondrocyte implantation, respectively), which increased in both groups to 70.56 +/- 12.39 and 72.63 +/- 15.55 at 6 months, 73.26 +/- 14.66 and 73.10 +/- 16.01 at 12 months, and 74.73 +/- 17.01 and 75.04 +/- 14.50 at 18 months, respectively. Both techniques were generally well tolerated; the incidence of adverse events after characterized chondrocyte implantation was not markedly increased compared with that for microfracture. CONCLUSION: One year after treatment, characterized chondrocyte implantation was associated with a tissue regenerate that was superior to that after microfracture. Short-term clinical outcome was similar for both treatments. The superior structural outcome may result in improved long-term clinical benefit with characterized chondrocyte implantation. Long-term follow-up is needed to confirm these findings.

Regeneration of the skeleton by recombinant human bone morphogenetic proteins.

Recombinant human bone morphogenetic proteins (rhBMPs) have past a long journey in human orthopaedic surgery during the last 15 years. From the first reports of the use of rhBMPs in hostile environments such as critically-sized bone defects, avascular femoral head necrosis, unstable thoracolumbar vertebral fractures, instability between the atlas and axis due to rheumatoid arthritis; over the use for nonunions of long bones and the scaphoid, reconstructive and revision surgeries of the hip, acute fractures, allograft nonunions, congenital pseudarthrosis, and various approaches of lumbar and cervical spine fusions, rhBMPs overgrow to a safe and reliable device in the treatment of open tibial shaft fractures, nonunions of long bone fractures, anterior lumbar interbody fusion and revision posterolateral lumbar fusions. Systematic review of the published literature of rhBMPs is presented.

[Cultivation and implantation of chondrocytes]. / Uzgoj i primjena hrskavicnih stanica.

Autologous chondrocyte transplantation is applied in patients with symptomatic articular cartilage defect due to a prior unsuccessful procedure on damaged cartilage, with a purpose to regenerate the cartilage. The procedure starts with an orthopedic surgeon establishing chondral defect in a joint and, during the knee arthroscopy, referring to the laboratory a cartilage biopsy specimen of a rice size from a non-weight-bearing part of the joint (usually the lateral part of the knee trochlea). Qualified biologists and technicians at the laboratory will then separate the cartilage cells from the extracellular matrix, followed by storing parts of healthy cartilage (300-500 mg) into a medium containing antibiotics, antimycotics and ascorbic acid, Individual cartilage cells (chondrocytes) will be isolated by enzymatic digestion. Chondrocytes are finally grown in sterile conditions in the patient's autologous serum during the next 14-21 days. During that time, the culture medium is tested several times in the micro laboratory and the cells' chondrogenic phenotype is determined. Multiplied chondrocytes are then removed from the bottom of the dish, washed several times, counted and prepared in a low volume medium (50-100 microL) suitable for implantation into the injured joint. During the surgery, orthopedic surgeon injects the cell implant under the periosteum or a similar biological membrane covering the defect. Active joint movement starts after 2-3 days, and full weight bearing is achieved in the next several weeks, following the rehabilitation protocol. Full physical condition is achieved within one year. Autologous chondrocyte transplantation is used for treatment of focal articular cartilage defects in the early stages of the disease, thus preventing or delaying progression to osteoarthritis and, consequently, replacement of the joint by an endoprosthesis.