Bipolar Lesions of the Knee Are Associated With Inferior Clinical Outcome Following Articular Cartilage Regeneration. A Propensity Score-Matched Analysis Including 238 Patients of the German Cartilage Registry (KnorpelRegister DGOU).

PURPOSE: To determine whether bipolar lesions (BL) are associated with inferior clinical outcome following articular cartilage regeneration (CR) compared to unipolar lesions (UL). METHODS: A registry-based study, including patients undergoing isolated CR for focal knee cartilage lesions was performed. Lesions were considered UL or BL depending on the opposing cartilage. Propensity score matching was applied to eliminate potential confounders. Two groups comprising 119 patients with similar baseline characteristics were matched. The Knee Injury and Osteoarthritis Outcome Score (KOOS) at baseline, 6, 12, 24, and 36 months following CR served as primary outcome measure. KOOS improvement, reaching the minimal clinically important difference (MCID), KOOS subcomponents, and failure rates were calculated. RESULTS: Autologous chondrocyte implantation (ACI) was the most frequently performed procedure in both groups with 63.0% (BL) and 46.6% (UL). There was a significant difference regarding KOOS at 24 months between UL (76.39 ± 14.96) and BL (69.83 ± 18.83; P = .028), which did not exceed the threshold of MCID. No significant difference was detected at any other follow-up. KOOS improvement from baseline was lower in the BL group at all follow-ups and peaked at 36 months in both groups (UL [26.00 ± 16.12] vs. BL [16.63 ± 17.29]; P = .024). The failure rate in the BL group was higher at 8.2% (9/110) compared to the UL group at 3.9% (4/98) (P = .256). CONCLUSIONS: BL were associated with worse clinical outcome 2 years following CR compared to UL. However, both groups showed an ongoing clinical improvement up to 3 years postoperatively and a low failure rate. While inferior clinical improvement and a lower clinical response rate may be expected in BL patients, the observed differences do not justify excluding these patients from CR. LEVEL OF EVIDENCE: Level III, retrospective comparative prognostic trial.

Current practice of concomitant surgeries in cartilage repair of the femorotibial compartment of the knee: baseline data of 4968 consecutive patients from the German cartilage registry (KnorpelRegister DGOU).

INTRODUCTION: The treatment of underlying comorbidities is a field of rising interest in cartilage repair surgery. The aim of this study was to analyze the current practice of concomitant surgeries in cartilage repair of the knee especially in the medial or lateral femorotibial compartment. Type, frequency and distribution of additional surgeries for correction of malalignment, knee instability and meniscus deficiency should be evaluated. METHODS: Baseline data of 4968 patients of the German Cartilage Registry (KnorpelRegister DGOU) were analyzed regarding the distribution of concomitant surgeries in addition to regenerative cartilage treatment. RESULTS: Beyond 4968 patients 2445 patients with cartilage defects in the femorotibial compartment of the knee could be identified. Of these patients 1230 (50.3%) received additional surgeries for correction of malalignment, instability and meniscus deficiency. Predominant procedures were leg axis corrections (31.3%), partial meniscectomy (20.9%) and ACL reconstruction (13.4%). The distribution of the concomitant surgeries varied between cartilage defects according to the different defect genesis. Patients with traumatic defects were younger (36y) and received predominantly ACL reconstructions (29.2%) (degenerative: 6.7%), whereas patients with degenerative defects were older (43y) and underwent predominantly leg axis corrections (38.0%; traumatic: 11.0%). CONCLUSIONS: This study shows the high frequency and distinct distribution of the concomitant surgeries in addition to regenerative cartilage treatment procedures. Understanding of the underlying cause of the cartilage defect and addressing the comorbidities as a whole joint therapy are of utmost importance for a successful regenerative cartilage treatment. These data provide a baseline for further follow up evaluations and long-term outcome analysis. LEVEL OF EVIDENCE: II.

Anatomic repair and ligament bracing as an alternative treatment option for acute combined PCL injuries involving the posteromedial or posterolateral corner-results of a multicentre study.

INTRODUCTION: Combined PCL injuries involving the posteromedial/-lateral corner (PMC/PLC) usually require surgical management. Literature shows controversy regarding the standards of treatment. Suture-augmented repair leads to excellent results in acute knee dislocations but has not been investigated clinically in combined PCL injuries. The purpose of this multicentre study was to evaluate the clinical outcome of this technique in acute combined PCL injuries. MATERIALS & METHODS: N = 33 patients with acute combined PCL injuries involving the PMC/PLC were treated by one-stage suture repair with ligament bracing of the PCL and suture repair of the accompanying PMC/PLC injuries with/without ligament bracing or primary augmentation by semitendinosus autograft. Outcome was assessed by IKDC questionnaire, Lysholm Score, Tegner Activity Scale and KOOS. Additional PCL stress-radiography was performed. RESULTS: N = 31 patients with combined PCL injuries (female: male = 7:24; age 39.1 ± 13.8 years) with a follow-up of 16.8 ± 9.6 months were finally evaluated. 18 had PMC injuries, 13 PLC injuries. 32.2% presented with accompanying meniscal tears (70% medial meniscus). 19.4% showed cartilage injuries grade III-IV. Complications included one infection and four knee stiffnesses. Three had symptomatic postoperative instability, all affiliated to the PLC group. The IKDC was 69.8 ± 16.5, Lysholm score 85 ± 14.4 and KOOS 89.7 ± 8.1. Median loss of activity (Tegner) was 0.89 ± 1.31. Comparing PMC and PLC, all scores showed a tendency towards more favourable outcomes in the PMC group (n.s.). Stress-radiography showed an overall side-to-side difference of 3.7 ± 3.8 mm. Subgroup evaluation showed statistically significant better results (p = 0.035) of PMC (2.5 ± 1.5 mm) versus PLC (5.8 ± 5.6 mm). CONCLUSIONS: One-stage suture repair with ligament bracing is a viable technique for acute combined PCL injuries and predominantly leads to good and excellent clinical outcomes. Patients with PLC injuries show a tendency towards inferior outcomes and higher instability rates compared to PMC injuries. These results may help in therapy planning and counselling patients with these rare injury pattern. LEVEL OF EVIDENCE: Level II.

Cell-based treatment options facilitate regeneration of cartilage, ligaments and meniscus in demanding conditions of the knee by a whole joint approach.

PURPOSE: This article provides an update on the current therapeutic options for cell-based regenerative treatment of the knee with a critical review of the present literature including a future perspective on the use of regenerative cell-based approaches. Special emphasis has been given on the requirement of a whole joint approach with treatment of comorbidities with aim of knee cartilage restoration, particularly in demanding conditions like early osteoarthritis. METHODS: This narrative review evaluates recent clinical data and published research articles on cell-based regenerative treatment options for cartilage and other structures around the knee RESULTS: Cell-based regenerative therapies for cartilage repair have become standard practice for the treatment of focal, traumatic chondral defects of the knee. Specifically, matrix-assisted autologous chondrocyte transplantation (MACT) shows satisfactory long-term results regarding radiological, histological and clinical outcome for treatment of large cartilage defects. Data show that regenerative treatment of the knee requires a whole joint approach by addressing all comorbidities including axis deviation, instability or meniscus pathologies. Further development of novel biomaterials and the discovery of alternative cell sources may facilitate the process of cell-based regenerative therapies for all knee structures becoming the gold standard in the future. CONCLUSION: Overall, cell-based regenerative cartilage therapy of the knee has shown tremendous development over the last years and has become the standard of care for large and isolated chondral defects. It has shown success in the treatment of traumatic, osteochondral defects but also for degenerative cartilage lesions in the demanding condition of early OA. Future developments and alternative cell sources may help to facilitate cell-based regenerative treatment for all different structures around the knee by a whole joint approach. LEVEL OF EVIDENCE: IV.

Higher risk of ACL rupture in amateur football compared to professional football: 5-year results of the 'Anterior cruciate ligament-registry in German football'.

PURPOSE: Anterior cruciate ligament (ACL) injuries are a common severe type of football injury at all levels of play. A football-specific ACL registry providing both prospective ACL injury data according to the skill level and risk factors for ACL injury is lacking in the literature. METHODS: This study is based on the prospective 'ACL registry in German Football' implemented in the 2014-15 season. Professional (1st-3rd league), semi-professional (4th-6th league) and amateur leagues (7th league) were analysed regarding the incidence and risk factors for ACL injuries. Injuries were registered according to the direct reports of the injured players to the study office and double-checked via media analysis. After injury registration, the players received a standardised questionnaire. Data were analysed from the 2014-15 to the 2018-19 football season. RESULTS: Overall, 958 ACL injuries were registered during the 5-year study period. The incidence of ACL injuries was highest in amateur football (0.074/1000 h football exposure) compared to professional (0.058/1000 h; p < 0.0001) and semi-professional football (0.043/1000 h; p < 0.0001). At all skill levels, match incidence (professional: 0.343; semi-professional: 0.249; amateur: 0.319) was significantly higher than training incidence (professional: 0.015; semi-professional: 0.004; amateur: 0.005). Major risk factors were previous ACL injury (mean: 23.3%), other knee injuries (mean: 19.3%) and move to a higher league (mean: 24.2%). CONCLUSION: This sports-specific ACL registry provides detailed information on the incidence and risk factors for ACL injuries in football over five years. Risk factors are skill level, match exposure, move to a higher league and previous knee injury. These factors offer potential starting points for screening at-risk players and applying targeted prevention. LEVEL OF EVIDENCE: II.

[Current treatment standard for patella fractures in Germany]. / Aktueller Versorgungsstandard von Patellafrakturen in Deutschland.

BACKGROUND: The treatment of patella fractures is technically demanding. Although the radiological results are mostly satisfactory, this often does not correspond to the subjective assessment of the patients. The classical treatment with tension band wiring with K­wires has several complications. Fixed-angle plate osteosynthesis seems to be biomechanically advantageous. OBJECTIVE: Who is treating patella fractures in Germany? What is the current standard of treatment? Have modern forms of osteosynthesis become established? What are the most important complications? MATERIAL AND METHODS: The members of the German Society for Orthopedics and Trauma Surgery and the German Knee Society were asked to participate in an online survey. RESULTS: A total of 511 completed questionnaires were evaluated. Most of the respondents are specialized in trauma surgery (51.5%), have many years of professional experience and work in trauma centers. Of the surgeons 50% treat ≤5 patella fractures annually. In almost 40% of the cases preoperative imaging is supplemented by computed tomography. The classical tension band wiring with K­wires is still the preferred form of osteosynthesis for all types of fractures (transverse fractures 52%, comminuted fractures 40%). In the case of comminuted fractures 30% of the surgeons choose fixed-angle plate osteosynthesis. If the inferior pole is involved a McLaughlin cerclage is used for additional protection in 60% of the cases. DISCUSSION: The standard of care for patella fractures in Germany largely corresponds to the updated S2e guidelines. Tension band wiring is still the treatment of choice. Further (long-term) clinical studies are needed to verify the advantages of fixed-angle plates.

Decision making for concomitant high tibial osteotomy (HTO) in cartilage repair patients based on a nationwide cohort study of 4968 patients.

BACKGROUND: High tibial osteotomy (HTO) for varus deformities is a common concomitant treatment in cartilage surgery. Aim of the present study was to analyze factors influencing the decision towards accompanying HTO in patients with cartilage defects of the medial femoral condyle, such as the amount of varus deformity. METHODS: Data from 4986 patients treated for cartilage defects of the knee from the German Cartilage Registry (KnorpelRegister DGOU) were used for the current analysis. Seven hundred and thirty-six patients fulfilled the inclusion criteria. Their data were analyzed for factors influencing the decision towards performing a concomitant HTO using t test, univariate and multivariate binary logistic regression models. RESULTS: The break point at which the majority of patients receive a concomitant HTO is 3° of varus deformity. Several factors apart from the amount of varus deformity (5.61 ± 2.73° vs. 1.72 ± 2.38°, p < 0.00) differed significantly between the group of patients with HTO and those without. These included defect size (441.6 ± 225.3 mm2 vs. 386.5 ± 204.2 mm2, p = 0.001), symptom duration (29.53 ± 44.58 months vs. 21.85 ± 34.17 months, p = 0.021), defect grade (62.5% IVa/IVb vs. 57.3% IVa/IVb, p = 0.014), integrity of corresponding joint surface (10.8% grade III-IV vs. 0.2% grade III-IV, p < 0.001), meniscus status (15.5% > 1/3 resected vs. 4.4% > 1/3 resected, p < 0.001) and number of previous surgeries (1.01 ± 1.06 vs. 0.75 ± 1.00, p = 0.001). In the stepwise multivariate binary logistic regression test, only the amount of varus deformity, symptom duration and quality of the corresponding joint surface remained significant predictors associated with performing a concomitant HTO. CONCLUSION: Based upon data from a nationwide cohort, additional HTO in context with cartilage repair procedures of the medial femoral condyle is frequently performed even in mild varus deformities less than 5°. Other factors also seem to influence decision for HTO.

Influence of poor preparation and sleep deficit on injury incidence in amateur small field football of both gender.

INTRODUCTION: Amateur small-field football tournaments are rather common worldwide. Adequate preparation is essential for injury prevention. The consequences of insufficient injury preparation at this level are still unclear. This study investigates the factors influencing injuries in this football population. MATERIALS AND METHODS: In 2017, medical students participating in a national amateur football tournament were analysed in a prospective cohort study. Injury incidence, injury pattern and factors influencing injuries were investigated according to the statement on data collection and injury definition of Fuller et al. (Br J Sports Med 40:193-201, 2006). Preparation for the tournament was assessed for both sexes by means of hours of sleep, alcohol consumption, training level and warm-up performance. LEVEL OF EVIDENCE: II. RESULTS: Of 694 amateur football players (423 men and 271 women) with a mean age of 23 years (SD 2.5), 321 (21.1%) injuries happened during the tournament. 60% of injuries affected the lower extremity. The most common types of traumatic injury were skin abrasions (40.0%) and muscle strains (23.3%). The injury incidence of male players during match exposure was 469 per 1000 h football and significantly higher than in female players 313 (p = 0.025). One potential reason for the higher injury rate of male players as measure for inadequate preparation was significantly higher alcohol consumption the evening before the tournament (p < 0.001) and the after-effects on match day (p < 0.001). Additionally, male players reported less and inadequate sleep the night before the tournament (p < 0.007) and a lower warm-up rate before the matches compared to female players (p < 0.001). CONCLUSIONS: Small-field tournaments in football have a high injury incidence. Male players have a higher injury incidence than female players and show additionally a lack of sleep and alcohol consumption the night before the tournament and poor warm-up performance on match day. Adequate preparation for a football tournament is the key factor for preventing injuries, also in recreational football.

[Violence and aggression in hospitals-what if the personnel need help?] / Gewalt und Aggression im Krankenhaus ­ Was, wenn das Personal Hilfe braucht?

In view of the increasing violence and aggression against medical personnel in healthcare facilities, there are considerations by the legislature to punish violent offenders in hospitals more severely. Hospital and emergency room staff are increasingly confronted by physically and psychologically violent patients or their relatives. Sometimes medical treatment in a hospital or emergency room is an exceptional physical or mental situation for many patients and their relatives. In addition, the consumption of alcohol and drugs, long waiting times, psychiatric illnesses and dissatisfaction with medical care or communication problems are considered to be the cause of violence against medical personnel in healthcare facilities. In addition to the physical consequences for the affected employees, the psychological consequences, such as job dissatisfaction, fear of work and posttraumatic stress disorder also pose major challenges for the employer. In order to fulfil the obligation of care towards employees, the latter should provide concepts for protection against violence as part of the company health management. Structural, organizational and personal measures as well as concepts for dealing with aggressive patients are the cornerstones of employee protection. Professional training courses on de-escalation, self-protection and self-defense can also contribute to the protection of employees and are gladly accepted by the staff. Even in the extreme case of a rampage situation, hospital deployment and alarm plans have to be developed and established.

The Importance of Physioxia in Mesenchymal Stem Cell Chondrogenesis and the Mechanisms Controlling Its Response.

Articular cartilage covers the surface of synovial joints and enables joint movement. However, it is susceptible to progressive degeneration with age that can be accelerated by either previous joint injury or meniscectomy. This degenerative disease is known as osteoarthritis (OA) and it greatly affects the adult population. Cell-based tissue engineering provides a possible solution for treating OA at its earliest stages, particularly focal cartilage lesions. A candidate cell type for treating these focal defects are Mesenchymal Stem Cells (MSCs). However, present methods for differentiating these cells towards the chondrogenic lineage lead to hypertrophic chondrocytes and bone formation in vivo. Environmental stimuli that can stabilise the articular chondrocyte phenotype without compromising tissue formation have been extensively investigated. One factor that has generated intensive investigation in MSC chondrogenesis is low oxygen tension or physioxia (2⁻5% oxygen). In vivo articular cartilage resides at oxygen tensions between 1⁻4%, and in vitro results suggest that these conditions are beneficial for MSC expansion and chondrogenesis, particularly in suppressing the cartilage hypertrophy. This review will summarise the current literature regarding the effects of physioxia on MSC chondrogenesis with an emphasis on the pathways that control tissue formation and cartilage hypertrophy.

Bone Marrow Aspirate Concentrate for the Treatment of Avascular Meniscus Tears in a One-Step Procedure-Evaluation of an In Vivo Model.

Avascular meniscus tears show poor intrinsic regenerative potential. Thus, lesions within this area predispose the patient to developing knee osteoarthritis. Current research focuses on regenerative approaches using growth factors or mesenchymal stem cells (MSCs) to enhance healing capacity within the avascular meniscus zone. The use of MSCs especially as progenitor cells and a source of growth factors has shown promising results. However, present studies use bone-marrow-derived BMSCs in a two-step procedure, which is limiting the transfer in clinical praxis. So, the aim of this study was to evaluate a one-step procedure using bone marrow aspirate concentrate (BMAC), containing BMSCs, for inducing the regeneration of avascular meniscus lesions. Longitudinal meniscus tears of 4 mm in size of the lateral New Zealand White rabbit meniscus were treated with clotted autologous PRP (platelet-rich plasma) or BMAC and a meniscus suture or a meniscus suture alone. Menisci were harvested at 6 and 12 weeks after initial surgery. Macroscopical and histological evaluation was performed according to an established Meniscus Scoring System. BMAC significantly enhanced regeneration of the meniscus lesions in a time-dependent manner and in comparison to the PRP and control groups, where no healing could be observed. Treatment of avascular meniscus lesions with BMAC and meniscus suturing seems to be a promising approach to promote meniscus regeneration in the avascular zone using a one-step procedure.

Reduced joint-awareness in bicruciate-retaining total knee arthroplasty compared to cruciate-sacrificing total knee arthroplasty.

PURPOSE: There is rising impact of patient-reported outcome (PRO) measurement in joint arthroplasty over the past years. Bicruciate-retaining implants have shown more physiologic knee kinematics and provide superior proprioceptive capacities. The aim of this study was to evaluate if the functional properties of this new implant design lead to improved PRO results after total knee arthroplasty (TKA). METHODS: This prospective, controlled trial compares PRO of bicruciate-retaining total knee arthroplasty (BCR-TKA) to unicondylar knee arthroplasty (UKA) and standard posterior-stabilized total knee arthroplasty (PS-TKA). We evaluated 102 patients (34 patients in each group) 18 months postoperatively after knee arthroplasty. Primary outcome measure was the Forgotten Joint Score (FJS). RESULTS: The BCR-group showed the same level of joint awareness as the UKA-group (p = 0.999). The second control group of PS-TKA patients had a lower mean score value in the FJS compared to the BCR-group (p = 0.035) and UKA-group (p = 0.031). There was no correlation of age, gender, body mass index (BMI) and the FJS. No relevant floor- or ceiling effects occurred. CONCLUSIONS: This study found reduced joint awareness for BCR-TKA compared to a standard total knee arthroplasty. The score values of the BCR-group were equal to the UKA-group. Further prospective, randomized studies to investigate long-term survivorship of bicruciate-retaining implants are needed. LEVEL OF EVIDENCE: Level II.

Correction to: Intra-ligamentary autologous conditioned plasma and healing response to treat partial ACL ruptures.

With regards to Berardo Di Matteo, second author. The author's name is incorrectly listed on Pub-Med. The first and last name have been mixed up.

Intra-ligamentary autologous conditioned plasma and healing response to treat partial ACL ruptures.

INTRODUCTION: Conservative treatment of partial ACL ruptures is associated with a high failure rate, and often patients undergo ACL reconstruction. ACL preservation by trephination of the ACL origin and application of Autologous Conditioned Plasma (ACP) seems to be an intriguing new treatment option to favour ACL tissue healing and avoid traditional reconstruction. The aim of this study was to describe the mid-term outcomes of this new ACL preserving technique. MATERIALS AND METHODS: Twenty-four patients (mean age 41.8 years) affected by partial rupture of one or both ACL bundles were included in the present trial. The partial ACL tears were arthroscopically assessed and classified according to a new five step grading system. All patients were treated by trephination of the femoral ACL stump and intra-ligamentary application of ACP. The postoperative outcome was evaluated by both subjective scores and stability testing up to a mean of 25.1 months' follow-up. Adverse events and failure rate were also documented. RESULTS: Clinical outcome was good to excellent with IKDC subjective 82.7 (SD 11.8), Lysholm 87.6 (SD 8.1), Tegner 5.3 (SD 2.1), Cincinnati 88.7 (SD 14.8). The failure rate (i.e. persisting knee instability assessed clinically or by rolimeter) was 12.5%. At objective measurements, knee joints showed a firm endpoint in Lachman test, negative pivot shift phenomenon and a significant reduction in AP-laxity compared to pre-operative status by rolimeter testing (p = 0.002). Return to sport practice was achieved after mean 4.8 months (SD 4.1). CONCLUSIONS: ACL stump trephination and concomitant intra-ligamentary application of ACP revealed promising results at mid-term follow-up to treat partial ACL lesions.

Sports-specific differences in postsurgical infections after arthroscopically assisted anterior cruciate ligament reconstruction.

PURPOSE: Post-operative infection after arthroscopically assisted anterior cruciate ligament (ACL) reconstruction is a rare but severe complication, particularly for young and active patients. It is unclear whether the prevalence of knee infection is correlated with the type of sports or the level of performance. METHODS: From 2008 to 2012, the internal single-centre ACL registry of the FIFA Medical Centre of Excellence Regensburg was retrospectively screened for sex, age, time between isolated primary ACL rupture and surgery, surgical technique, rate of infection after ACL reconstruction and the type of sports practised. RESULTS: In total, 4801 ACL reconstructions had been conducted over 5 years, 4579 in amateur and 221 in professional athletes. After application of the exclusion criteria, 1809 athletes with ACL reconstruction were analysed regarding postsurgical infection and the type of sports practised. Professionals and amateurs did not significantly differ with regard to infection rates (n.s.) but in the timing of ACL repair (p < 0.001). Eleven of 1130 football players had developed postsurgical infection after ACL reconstruction (1.0%) in contrast to 557 skiers and snowboarders without infection (p = 0.02). The timing of ACL repair did not differ between the different types of sports (n.s.). Staphylococcus aureus and epidermidis were the predominant detected bacteria. All patients were hospitalised and successfully treated with arthroscopic lavage and antibiotic medication. CONCLUSION: ACL infections showed sports-related differences. Athletes practising summer outdoor sports such as football had a significantly higher risk of infection after ACL reconstruction than winter sports athletes. No difference was found between professional and amateur athletes. Relevant prevention strategies for postsurgical ACL infections should consider influencing patient factors such as the type of sports activity and attendant circumstances. LEVEL OF EVIDENCE: III.

Proprioception after bicruciate-retaining total knee arthroplasty is comparable to unicompartmental knee arthroplasty.

PURPOSE: Rising expectations in functional performance of total knee joints are inciting further improvement of knee arthroplasty implants. From a patient-centred view, bicruciate-retaining models provide a more natural feeling knee. However, there is no evidence of functional advantage for these implants. The aim of this study was to evaluate balance ability as a measure of proprioception in patients with a bicruciate-retaining total knee arthroplasty. METHODS: A prospective, controlled trial was conducted to compare balance ability in 60 patients after arthroplasty of the knee for osteoarthritis. We compared patients with a bicruciate-retaining knee arthroplasty (BCR group) to a control group of patients with a medial unicompartmental knee arthroplasty (UKA group) and another control group of patients with a posterior stabilized total knee arthroplasty (PS group). The patient population comprised 30 women (50.0 %) and 30 men in three cohorts of 20 each. The mean age was 62.1 ± 8.0 years (range 43-78). Patients were evaluated preoperatively and 9 months post-operatively. The evaluation included clinical, radiological, and balance testing-a single-leg stance with eyes closed compared to eyes open. The difference in area of sway between eyes closed and eyes open represents static balance ability after knee arthroplasty. RESULTS: Perioperative data showed that there was no intra-operative fracture of the intercondylar eminence. There was a decreased post-operative knee extension 9 months post-operative in the BCR group, which was not clinically relevant in any case. We recorded a lower difference in the area of sway between eyes closed and eyes open (ΔA (ec-eo)) for the BCR group (p = 0.01) and the UKA group (p = 0.04) compared to the PS group. CONCLUSIONS: This study found superior static balance ability after preservation of both cruciate ligaments in arthroplasty of the knee, indicating superior proprioceptive function. Hence, BCR implants could provide improved functional properties. Superior proprioceptive function of bicruciate-retaining implants can be an important factor in implant selection. Further prospective, randomized studies to investigate kinematics and long-term survivorship of bicruciate-retaining implants are needed. LEVEL OF EVIDENCE: II.

Leukocyte-reduced platelet-rich plasma increases proliferation of tenocytes treated with prednisolone: a cell cycle analysis.

INTRODUCTION: The purpose of this study was to evaluate the effect of allogenic leukocyte-reduced platelet-rich plasma on human tenocytes after treatment with prednisolone and to develop a standardization of its application for clinical practice. METHODS: A leukocyte-reduced PRP was produced using the Arthrex Double Syringe (Arthrex, Inc., Naples, FL, USA), in a modified single-spin separation method. Human tenocytes were isolated from discarded rotator cuff segments. Tenocytes were cultured in the presence of PRP and prednisolone, both alone and in combination. Control samples were treated in media containing 2% FCS for 72 h. After 72 h of incubation, cell cycle kinetics of tenocytes were analyzed to assess proliferation. RESULTS: Incubation of the tenocytes with PRP alone for 48 h led to high proliferation rate (10% PRP, 28.0 ± 10.5%; 20% PRP, 40.9 ± 3.3%). Incubation in the presence of prednisolone led to a significant decrease of the proliferation rate (5.2 ± 3.1%; p < 0.05). Treatment with PRP for 48 h significantly increased the proliferation of tenocytes in a dose-dependent manner (10% PRP, 28.0 ± 10.5%; 20% PRP, 40.9 ± 3.3%; p < 0.05). The presence of prednisolone resulted in a decreased tenocyte proliferation (5.2 ± 3.1%; p < 0.05), whereas addition of PRP for 24 and 48 h after prednisolone exposure did not show any compensating effect independent of PRPs concentration (10% PRP, 3.7 ± 3.0%; 20% PRP, 2.5 ± 2.5%). However, a significantly increased cell proliferation of tenocytes was evident when PRP was applied 24 h after prednisolone incubation for 48 h (31.0 ± 3.4 and 34.3 ± 4.7%). CONCLUSION: The use of leukocyte-reduced PRP stimulates the proliferation of tenocytes and antagonizes the negative effect of prednisolone 24 h after treatment. Addition of PRP 48 h after treatment with prednisolone has no positive effect on the proliferation rate of tenocytes.

Increase in ACL and PCL injuries after implementation of a new professional football league.

PURPOSE: In the season 2008-2009, a third professional football league was established in Germany. This study analysed the influence of increased training and playing intensity on severe knee injuries in football players. METHODS: In a prospective controlled one-season trial, injury incidence and injury patterns of players of the newly established professional football league were analysed, particularly with regard to ruptures of the anterior (ACL) and posterior (PCL) cruciate ligaments. Players of the highest amateur level served as a control group. RESULTS: Four hundred and eight players of 24 teams were allocated to two groups. The overall training exposure was significantly (p < 0.001) higher in the new professional league (335.3 h per player) than at the amateur level (286.6 h per player). Players at both levels showed similar overall injury rates and injury patterns. However, players in the professional league had a significantly higher (p = 0.04) incidence of ACL and PCL injuries, than players at the amateur level. More than 90 % of all ACL and PCL ruptures in both groups were sustained by players, who had played at least one level lower in the previous season. In addition, injuries of players who had sustained repeat injuries over the season were more severe. CONCLUSION: The introduction of a new professional football league increased the training and playing intensity of players as well as the number of ACL and PCL ruptures. A specific injury prevention concept, particularly for players facing rapidly increasing training and playing intensity, seems to be mandatory. LEVEL OF EVIDENCE: Prospective controlled cohort study, Level II.