Nonoperative and Operative Soft-Tissue, Cartilage, and Bony Regeneration and Orthopaedic Biologics of the Elbow and Upper Extremity: An Orthoregeneration Network Foundation Review.

Orthoregeneration is defined as a solution for orthopaedic conditions that harnesses the benefits of biology to improve healing, reduce pain, improve function, and, optimally, provide an environment for tissue regeneration. Options include drugs, surgical intervention, scaffolds, biologics as a product of cells, and physical and electromagnetic stimuli. The goal of regenerative medicine is to enhance the healing of tissue after musculoskeletal injuries as both isolated treatment and adjunct to surgical management, using novel therapies to improve recovery and outcomes. Various orthopaedic biologics (orthobiologics) have been investigated for the treatment of pathology involving the elbow and upper extremity, including the tendons (lateral epicondylitis, medial epicondylitis, biceps tendonitis, triceps tendonitis), articular cartilage (osteoarthritis, osteochondral lesions), and bone (fractures, nonunions, avascular necrosis, osteonecrosis). Promising and established treatment modalities include hyaluronic acid; botulinum toxin; corticosteroids; leukocyte-rich and leukocyte-poor platelet-rich plasma; autologous blood; bone marrow aspirate comprising mesenchymal stromal cells (alternatively termed medicinal signaling cells and frequently mesenchymal stem cells [MSCs]) and bone marrow aspirate concentrate; MSCs harvested from adipose and skin (dermis) sources; vascularized bone grafts; bone morphogenic protein scaffold made from osteoinductive and conductive ß-tricalcium phosphate and poly-ε-caprolactone with hydrogels, human MSCs, and matrix metalloproteinases; and collagen sponge. Autologous blood preparations such as autologous blood injections and platelet-rich plasma show positive outcomes for nonresponsive tendinopathy. In addition, cellular therapies such as tissue-derived tenocyte-like cells and MSCs show a promising ability to regulate degenerative processes by modulating tissue response to inflammation and preventing continuous degradation and support tissue restoration.

Females show worse functional outcome and quality of life compared to males 2 years after meniscus surgery: Data analysis from the German Arthroscopy Registry.

PURPOSE: The purpose of this study was to investigate the impact of sex on knee function, activity and quality of life following meniscus surgery using data from the German Arthroscopy Registry. METHODS: This is a retrospective cohort study with data collected between 2017 and 2022. Patient-reported outcome measures (PROMs), namely Knee Injury and Osteoarthritis Outcome Score (KOOS), EuroQol Visual Analogue Scale (EQ Scale), and Marx Activity Rating Scale (MARS), were collected preoperatively and at 6, 12 and 24 months postoperatively. Data were analysed to examine differences between male and female patients regarding PROMs, pre-existing conditions, meniscus lesion types and surgical treatments. RESULTS: A total of 1106 female (36.6%) and 1945 male patients (63.7%) were included. Males were significantly younger than females and had a higher body mass index. Overall, there were four times more medial meniscus lesions (MMLs) (77.5%) than lateral meniscus lesions (LMLs) (27.9%). Degenerative LMLs were more frequent in females, while traumatic LMLs were more common in males. Frequencies of traumatic and degenerative MMLs were similar among males and females. Males had higher absolute KOOS irrespective of treatment or meniscus lesion type. Meniscus repair resulted in similar improvements in ΔKOOS for both sexes, while meniscus resection exhibited higher absolute KOOS for males at each time point. Males generally had higher EQ Scale and MARS than females. CONCLUSION: Greater improvements in knee function, activity and quality of life were observed in males. While MMLs appear to be comparable among sexes, the nature of LML differed significantly. These results may help surgeons to refine patient selection for specific treatments to improve overall clinical outcomes. LEVEL OF EVIDENCE: Level III.

Long-term cost-effectiveness of matrix-associated chondrocyte implantation in the German health care system: a discrete event simulation.

INTRODUCTION: Cartilage defects in the knee can be caused by injury, various types of arthritis, or degeneration. As a long-term consequence of cartilage defects, osteoarthritis can develop over time, often leading to the need for a total knee replacement (TKR). The treatment alternatives of chondral defects include, among others, microfracture, and matrix-associated autologous chondrocyte implantation (M-ACI). The purpose of this study was to determine cost-effectiveness of M-ACI in Germany with available mid- and long-term outcome data, with special focus on the avoidance of TKR. MATERIALS AND METHODS: We developed a discrete-event simulation (DES) that follows up individuals with cartilage defects of the knee over their lifetimes. The DES was conducted with a status-quo scenario in which M-ACI is available and a comparison scenario with no M-ACI available. The model included 10,000 patients with articular cartilage defects. We assumed Weibull distributions for short- and long-term effects for implant failures. Model outcomes were costs, number of TKRs, and quality-adjusted life years (QALYs). All analyses were performed from the perspective of the German statutory health insurance. RESULTS: The majority of patients was under 45 years old, with defect sizes between 2 and 7 cm2 (mean: 4.5 cm2); average modeled lifetime was 48 years. In the scenario without M-ACI, 26.4% of patients required a TKR over their lifetime. In the M-ACI scenario, this was the case in only 5.5% of cases. Thus, in the modeled cohort of 10,000 patients, 2700 TKRs, including revisions, could be avoided. Patients treated with M-ACI experienced improved quality of life (22.53 vs. 21.21 QALYs) at higher treatment-related costs (18,589 vs. 14,134 € /patient) compared to those treated without M-ACI, yielding an incremental cost-effectiveness ratio (ICER) of 3376 € /QALY. CONCLUSION: M-ACI is projected to be a highly cost-effective treatment for chondral defects of the knee in the German healthcare setting.

Germany has a high demand in meniscal allograft transplantation but is subject to health economic and legal challenges: a survey of the German Knee Society.

PURPOSE: To determine the current status and demand of meniscal allograft transplantation (MAT) in Germany among members of the German Knee Society (= Deutsche Kniegesellschaft; DKG). METHODS: An online survey was conducted between May 2021 and June 2021 and sent to all members of the DKG. The survey questionnaire consisted of 19 questions to determine the demand and technical aspects of MAT among the participants and to identify areas of improvement in MAT in Germany. RESULTS: Overall, 152 participants, 136 (89.5%) from Germany, 8 (5.3%) from Switzerland, 6 (4.0%) from Austria, and 2 (1.3%) from other countries completed the online survey, with the majority working in non-academic institutions. According to the regulations of the DKG, 87 (57.2%) participants were board certified as specialized knee surgeons and 97 (63.8%) worked primarily in the field of orthopedic sports medicine. MAT was considered clinically necessary in Germany by 139 (91.5%) participants. Patient age (83.6%), post-meniscectomy syndrome in isolated lateral (79.6%) and medial (71.7%) meniscus deficiency, and functional and athletic demands (43.4%) were the most important determinants to consider MAT in patients. Participants reported that reimbursement (82.9%), jurisdiction over the use of donor grafts (77.6%), and the availability of meniscal allografts (76.3%) are the main challenges in performing MAT in Germany. The most frequently used meniscal allograft types by 54 (35.5%) participants who had already performed MAT were fresh-frozen grafts (56.6%), peracetic acid-ethanol sterilized grafts (35.9%), and cryopreserved grafts (7.6%). Participants reported to perform suture-only fixation more often than bone block fixation for both medial (73.6% vs. 22.6%) and lateral (69.8% vs. 24.5%) MAT. CONCLUSION: More than 90% of the responding members of the DKG indicated that MAT is a clinically important and valuable procedure in Germany. Reimbursement, jurisdiction over the use of donor grafts, and the availability of meniscal allografts should be improved. This survey is intended to support future efforts to facilitate MAT in daily clinical practice in Germany. LEVEL OF EVIDENCE: Level V.

The Medial structures of the knee have a significant contribution to posteromedial rotational laxity control in the PCL-deficient knee.

PURPOSE: Various reconstruction techniques have been employed to restore normal kinematics to PCL-deficient knees; however, studies show that failure rates are still high. Damage to secondary ligamentous stabilizers of the joint, which commonly occurs concurrently with PCL injuries, may contribute to these failures. The main objective of this study was to quantify the biomechanical contributions of the deep medial collateral ligament (dMCL) and posterior oblique ligament (POL) in stabilizing the PCL-deficient knee, using a joint motion simulator. METHODS: Eight cadaveric knees underwent biomechanical analysis of posteromedial stability and rotatory laxity using an AMTI VIVO joint motion simulator. Combined posterior force (100 N) and internal torque (5 Nm) loads, followed by pure internal/external torques (± 5 Nm), were applied at 0, 30, 60 and 90° of flexion. The specimens were tested in the intact state, followed by sequential sectioning of the PCL, dMCL, POL and sMCL. The order of sectioning of the dMCL and POL was randomized, providing n = 4 for each cutting sequence. Changes in posteromedial displacements and rotatory laxities were measured, as were the biomechanical contributions of the dMCL, POL and sMCL in resisting these loads in a PCL-deficient knee. RESULTS: Overall, it was observed that POL transection caused increased posteromedial displacements and internal rotations in extension, whereas dMCL transection had less of an effect in extension and more of an effect in flexion. Although statistically significant differences were identified during most loading scenarios, the increases in posteromedial displacements and rotatory laxity due to transection of the POL or dMCL were usually small. However, when internal torque was applied to the PCL-deficient knee, the combined torque contributions of the dMCL and POL towards resisting rotation was similar to that of the sMCL. CONCLUSION: The dMCL and POL are both important secondary stabilizers to posteromedial translation in the PCL-deficient knee, with alternating roles depending on flexion angle. Thus, in a PCL-deficient knee, concomitant injuries to either the POL or dMCL should be addressed with the aim of reducing the risk of PCL reconstruction failure.

Research productivity during orthopedic surgery residency correlates with pre-planned and protected research time: a survey of German-speaking countries.

PURPOSE: The purpose of this study was to identify modifiable factors associated with research activity among residents working in orthopedic surgery and traumatology. METHODS: Residents at 796 university-affiliated hospitals in Austria, Germany, and Switzerland were invited to participate. The online survey consisted of questions that ascertained 13 modifiable and 17 non-modifiable factors associated with the residents' current research activities. Responses of 129 residents were analyzed. Univariate linear regression was used to determine the association of individual factors with the current research activity (hours per week). The impact of significant non-modifiable factors (with unadjusted p values < 0.05) was controlled for using multivariate linear regression. RESULTS: The univariate analysis demonstrated six non-modifiable factors that were significantly associated with the current research activity: a University hospital setting (p < 0.001), an A-level hospital setting (p = 0.024), Swiss residents (p = 0.0012), the completion of a dedicated research year (p = 0.007), female gender (p = 0.016), and the department's size (p = 0.048). Multivariate regression demonstrated that the number of protected research days per year (p < 0.029) and the percentage of protected days, that were known 1 week before (p < 0.001) or the day before (p < 0.001), were significantly associated with a higher research activity. CONCLUSIONS: As hypothesized, more frequent and predictable protected research days were associated with higher research activity among residents in orthopedic surgery and traumatology. LEVEL OF EVIDENCE: III.

[Posterior meniscus root tears]. / Posteriore Wurzelverletzungen der Menisken.

Meniscus root tears are radial tears in the region of the posterior insertion zones. Medial root injuries usually occur in individuals > 50 years of age without adequate trauma and are associated with obesity and varus deformities. The root lesion leads to a loss of ring tension, which results in extrusion of the meniscus and a strong increase in joint pressure that is biomechanically equivalent to a complete meniscectomy. When indicating arthroscopic transosseous refixation of the medial root lesion, factors such as accompanying cartilage damage, osteoarthritis, obesity and varus deformity must be taken into account. Injuries to the root of the lateral meniscus are mostly observed in younger patients in combination with a rupture of the anterior cruciate ligament. Arthroscopic transosseous refixation in combination with cruciate ligament surgery is therefore also recommended for type I and type II lesions. In summary, both the medial and the lateral root lesions of the menisci are injuries with high biomechanical relevance.

Suture Tape Reduces Quadriceps Tendon Repair Gap Formation Compared With High-Strength Suture: A Cadaveric Biomechanical Analysis.

PURPOSE: To compare the biomechanical differences between quadriceps tendon (QT) repair with high-strength suture (HSS) versus suture tape (ST) with varying number of suture passes. METHODS: In total, 28 fresh-frozen QTs were randomized into 2 groups: (1) HSS; or (2) ST; specimens were then further randomized into subgroups of either 4 or 6 suture passes. Specimens were secured within a materials testing system and a 150-N preload was applied for 10 seconds followed by a cyclic loading protocol between 50 N and 250 N for 1000 cycles. Video was used to follow tracking markers used to calculate the magnitude of tendon displacement. Two-way univariate analysis of variance was used to determine the effect of suture type and passes on the displacement after preloading and mixed repeated-measures analysis of variance was used to determine the effect of suture type and passes on displacement following cyclic loading. RESULTS: There were large increases in displacement following the preload across all conditions (7.82 ± 3.64 mm), with no statistically significant differences between groups. There was a significant difference in the mean (± standard deviation) displacement between the ST (5.24 ± 2.82 mm) and HSS (7.93 ± 2.91 mm) starting at 200 cycles, which became more pronounced with successive testing out to 1000 cycles (P = .021). There were no significant difference with respect to the number of suture or tape passes. CONCLUSIONS: Following preloading at 150 N, significant displacement occurred in both QT repair groups. ST demonstrated significantly less displacement than HSS under cyclic loading and had greater ultimate failure loads. CLINICAL RELEVANCE: When performing QT repair, emphasis should be placed on appropriate pretensioning of sutures to at least 150 N before knot-tying. In addition, where available, ST should be used over HSS to reduce further cyclic elongation and improve ultimate failure loads.

Medial patellofemoral ligament reconstruction fails to correct mild patella alta in cases of patellofemoral instability-a case-control study.

PURPOSE: Medial patellofemoral ligament reconstruction (MPFL-R) is the gold standard in patella soft tissue surgery for patellofemoral instability. Although claimed, recent reports indicate that MPFL-R may fail to distalize the patella in mild cases of patella alta. The present study is a retrospective case-control study to compare radiographic patella height between MPFL-R and historical Insall's proximal realignment (IPR) pre- and post-operatively with respect to distalization and assess redislocation rates at a mid-term follow-up. METHODS: Sixty-four patients were age/sex matched (1:1), yielding 32 patients for group 1 MPFL-R (cases) and 32 patients for group 2 IPR (controls). Insall-Salvati, Blackburne-Peel and Caton-Deschamps indices were analyzed for differences pre- and post-operatively. An additional inter-rater reliability analysis was performed by means of intra-class correlation (ICC). Redislocation rates were considered as treatment failures in this study. RESULTS: ICC was excellent for all three patella indices. MPFL-R failed to show significant differences if compared to IPR with respect to distalization in mild stages of patella alta. Moreover, redislocation rates significantly favored MPFL-R (3.1%) over IPR (12.5%; p < 0.0001). CONCLUSIONS: MPFL-R has become a popular option to restore native patellofemoral biomechanics after ligament rupture. However, the procedure's potential to correct concomitant patella alta should not be overestimated and indications considered carefully.

Predictors for secondary patellar resurfacing after primary total knee arthroplasty using a "patella-friendly" total knee arthroplasty system.

PURPOSE: Patellar resurfacing (PR) in total knee arthroplasty (TKA) is still one of the major controversies in orthopaedic surgery today. The aim of the present retrospective case-control study was to identify predictors for secondary patellar resurfacing (SPR) after initial TKA to create a rationale for surgeons to decide which patients to resurface primarily. It was hypothesized that proper TKA implantation and component positioning as well as a maintained physiological patellar geometry will lead to a reduced risk of SPR. Overmore, it was hypothesized that intrinsic factors like overweight might also have an influence on the need for SPR. METHODS: After identification of suitable patients and age/sex matching in a 1:2 fashion, 29 cases (TKA/SPR) and 58 controls (TKA) were included and screened for available clinical and epidemiological data as well as for radiographic data after primary TKA. Pearson's correlation analysis as well as logistic regression modeling was performed to identify possible predictors for SPR following TKA. RESULTS: Binary logistic regression was able to correctly classify 88.5% of patients into case or control groups. It indicated that patella tilt, patella height, and thickness as well as the delta angle were significant predictors of a need for SPR following primary TKA. An increase in patellar width by 1 mm will increase the risk of SPR, while an increase in patellar thickness by 1 mm will reduce it. An increase in patellar tilt by 1° will also increase the risk of SPR. Finally, an increase in delta angle by 1° will again reduce the risk of SPR. CONCLUSIONS: Easy and accessible radiographic measurements have been identified as possible predictors of SPR following primary TKA. Although indication for primary PR may still remain a controversial topic, a rationale has been proposed in this study to support surgeons in objectively estimating an individual patient's risk for SPR prior to primary TKA measuring the patella tilt, width, and thickness. Overmore, regarding surgical aspects of TKA, tibial component positioning has also been shown to be of importance to reduce the risk of SPR.

The augment-and-modular-cage revision system for reconstruction of severe acetabular defects-two-year clinical and radiographic results.

PURPOSE: Acetabular revision of failed total hip arthroplasty (THA) is often associated with severe bone loss. Therefore, a variety of revision implant systems has been developed during recent years, with the augment-and-modular-cage system being one of the newest additions to this portfolio. Together with biologic downsizing by means of impaction bone grafting, this uncemented system promises a high modularity and versatility to treat all acetabular defects up to Paprosky types IIIa and IIIb without pelvic discontinuity. The aim of the present study was to evaluate first short-term results of its clinical application, both clinical functional and patient-reported as well as radiographic. METHODS: Forty-four patients (28 female, 16 male, mean age 70.9 ± 11.5 years) could be followed for a mean of 26 ± 10 months after acetabular revision with a novel augment-and-modular-cage system. Indications for revision included aseptic loosening (68%), septic loosening (16%), or others (16%) with bone loss Paprosky IIa up to IIIb without discontinuity. The modified Harris Hip Score (mHHS) served as a primary outcome parameter. In addition, a number of patient-reported outcome measurements (PROMs) were collected including the Short Form 36 (SF-36), Hip disability and Osteoarthritis Outcome Score (HOOS), and Visual Analogue Scale for Hip Pain (VAS Hip) as well as overall satisfaction. Radiographic changes between the pre- and postoperative center of rotation (COR) and various criteria of implant failure served as secondary outcome parameters. RESULTS: No patients were lost to follow-up. Two implant-associated complications (partial flange breakage) without a need for revision surgery were detected, which represent a failure rate of 4.5%. Functional outcome as measured by mHHS increased from 49.4 ± 2.9 pre-operatively to 74.4 ± 3.1 at the latest follow-up (p < 0.001). PROMs showed significant improvements in all pain-related categories, while other quality-of-life measurements only exhibited positive tendencies towards improvement. VAS Hip significantly improved from 6.5 ± 0.7 pre-operatively to 2.2 ± 0.6 at the latest follow-up (p < 0.001). Radiographic evaluation showed that reconstruction of the COR was possible, referenced to the contralateral side. The COR could be lateralized by 5.0 mm (n.s.) and caudalized by 10.3 mm (p < 0.001) comparing pre-operative and post-operative states, with complete osseointegration in 95% of the cases. CONCLUSIONS: Treatment with the augment-and-modular-cage system significantly improved clinical functional and patient-reported outcomes in cases of acetabular revision after failed THA. In addition, a good reconstruction of the COR could also be achieved. Therefore, this highly modular system can be considered as an effective treatment option in almost all cases of acetabular bone loss except for those of pelvic discontinuity. It offers the unique possibility of intra-operative implant customization according to the existing bone defect and host bone quality.

Rotator cuff muscular integrity after arthroscopic revision of a Bankart repair.

INTRODUCTION: Recurrent shoulder instability after arthroscopic Bankart repair is still a common complication. For primary Bankart repair studies have shown that the rotator cuff can recover completely. The ability of muscles to regenerate after arthroscopic revision Bankart repair (ARBR) has not been studied. Does the ARBR using a three-portal method allows complete muscle integrity compared with an uninjured imaging control group (ICG)? MATERIALS AND METHODS: Twenty-two (1 female, 21 males) physically active patients (mean age at follow-up 28.5 ± 7.1 years; mean follow-up 27.5 months ± 8.5) were assessed. ARBR with a three-portal method was carried out in all patients according to previous primary arthroscopic stabilization of the shoulder (revision Bankart group). Muscle atrophy of the subscapularis muscle (SSC), supraspinatus muscle (SSP) and infraspinatus muscle (ISP) was assessed by making lateral and vertical measurements by magnetic resonance imaging (MRI). Fatty infiltration was detected by standardized assessment from variations in intensity. Detailed clinical examination of the rotator cuff was carried out. MRI assessment was compared with that of a control group of 22 healthy volunteers of same age and activity level (ICG). RESULTS: For the SSC, no muscle impairment was noted compared with the ICG [superior atrophy index (sAISSC), p = 0.439; inferior atrophy index (iAISSC), p = 0.555; superior fatty infiltration index (sFDISSC), p = 0.294; inferior fatty infiltration index (iFDISSC), p = 0.62]. In investigation of the SSP and ISP, fatty infiltration was not shown (FDISSP, p = 0.454; sFDIISP, p = 0.504), though persistent muscle atrophy was found even > 2 years after surgery compared with the ICG (AISSP, p = 0.0025; sAIISP, p = 0.0009; iAIISP, p = 0.0004). CONCLUSION: ARBR using a three-portal method allowed good muscular integrity compared with the ICG, but with persistent slight muscular atrophy of the SSP and ISP.

Anatomic dissection of the anterolateral ligament (ALL) in paired fresh-frozen cadaveric knee joints.

INTRODUCTION: Different dissection studies as well as comparative studies about the anterolateral ligament of the knee (ALL) already exist and the structure's topology and properties have been shown. However, most of the studies investigating the ligament were performed in embalmed knees, which is thought to change the structural integrity of ligaments and thus the topologic and dynamic measurements. Since the biomechanical function of the ALL is not fully understood until today and a correlation with the pivot shift phenomenon is yet speculative, further studies will have to clarify its definitive importance. Its function as a limiter of internal rotation and lateral meniscal extrusion leads to the assumption of a secondary knee stabilizer. METHODS: Twenty paired fresh-frozen cadaveric knees of ten donors have been dissected in a layerwise fashion. After identification of the ALL, topologic measurements were undertaken using a digital caliper. RESULTS: The ALL could be identified as a tender, pearly structure in front of the anterolateral joint capsule in only 60% of the dissected knee joints. Only 20% of donors had a bilateral ALL while 80% had an ALL only in one side. Mean length, thickness and width as well as topographic measurements were comparable to other available studies investigating fresh-frozen cadavers. CONCLUSION: Anatomy and topography of the ALL seem to be highly variable, but consistent within certain borders. Prevalence has to be argued though as it strongly differs between studies. The impact of an ALL absence, even if only unilateral, needs to be investigated in clinical and imaging studies to finally clarify its importance.

Midterm follow-up after implantation of a polyurethane meniscal scaffold for segmental medial meniscus loss: maintenance of good clinical and MRI outcome.

PURPOSE: The preservation of meniscal structure and function after segmental meniscal loss is of crucial importance to prevent early development of osteoarthritis. Implantation of artificial meniscal implants has been reported as a feasible treatment option. The purpose of this study was to assess the clinical and magnetic resonance imaging (MRI) results 4 years after implantation of a polyurethane scaffold for chronic segmental medial meniscus deficiency following partial medial meniscectomy. METHODS: Eighteen patients received arthroscopic implantation of an Actifit(®) polyurethane meniscal implant (Orteq Sports Medicine, London, UK) for deficiency of the medial meniscus. Patients were followed at 6, 12, 24, and 48 months. Clinical outcome was assessed using established patient-reported outcome scores (KOOS, KSS, UCLA Activity Scale, VAS for pain). Radiological outcome was quantified by MRI scans after 6, 12, 24, and 48 months evaluating scaffold morphology, tissue integration, and status of the articular cartilage as well as signs of inflammation. RESULTS: Median patient age was 32.5 years (range 17-49 years) with a median meniscal defect size of 44.5 mm (range 35-62 mm). Continuing improvement of the VAS and KSS Knee and Function Scores could be observed after 48 months compared to baseline, whereas improvement of the activity level according to UCLA continued only up to 24 months and decreased from there on. The KOOS Score showed significant improvement in all dimensions. MRI scans showed reappearance of bone bruises in two patients with scaffold extrusion. No significant changes in the articular cartilage could be perceived. CONCLUSION: Arthroscopic treatment for patients with chronic segmental meniscal loss using a polyurethane meniscal implant can achieve sustainable midterm results regarding pain reduction and knee function. LEVEL OF EVIDENCE: IV.

The anterolateral ligament (ALL) and its role in rotational extra-articular stability of the knee joint: a review of anatomy and surgical concepts.

The anterolateral ligament of the knee (ALL) has caused a lot of rumors in orthopaedics these days. The structure that was first described by Segond back in 1879 has experienced a long history of anatomic descriptions and speculations until its rediscovery by Claes in 2013. Its biomechanical properties and function have been examined recently, but are not yet fully understood. While the structure seems to act as a limiter of internal rotation and lateral meniscal extrusion its possible proprioceptive effect remains questionable. Its contribution to the pivot shift phenomenon has been uncovered in parts, therefore it has been recognized that a concomitant anterolateral stabilization together with ACL reconstruction may aid in prevention of postoperative instability after severe ligamentous knee damages. However, there are a lot of different methods to perform this procedure and the clinical outcome has yet to be examined. This concise review will give an overview on the present literature to outline the long history of the ALL under its different names, its anatomic variances and topography as well as on histologic examinations, imaging modalities, arthroscopic aspects and methods for a possible anterolateral stabilization of the knee joint.

Systemic antibiotic therapy does not significantly improve outcome in a rat model of implant-associated osteomyelitis induced by Methicillin susceptible Staphylococcus aureus.

INTRODUCTION: Treatment of implant-associated osteomyelitis regularly involves the use of systemic antibiotics in addition to surgical intervention. However, it remains unclear if perioperative systemic application of bactericide substances can improve overall outcome in models of severe intramedullary infection. The present study investigated the use of systemic gentamicin in addition to a controlled local release from a highly lipophilic gentamicinpalmitate compound while the previous study showed efficacy of sole antibiotic implant-coating. METHODS: Forty male Sprague-Dawley rats were divided into two groups receiving an intramedullary femoral injection of 10(2) CFU of a common methicillin susceptible Staphylococcus aureus strain (MSSA Rosenbach). Group I received an uncoated implant whereas group II received a coated implant. All animals received a single shot intraperitoneal application of gentamicinsulfate directly after wound closure while the historical control group III (n = 20) had no antibiotic treatment at all. Animals were observed for 28 and 42 days. Serum haptoglobin and relative weight gain were assessed as well as roll over cultures of explanted femur nails and histological scores of periprosthetic infection in dissected femora. RESULTS: Systemic application of gentamicin combined with antibiotic-coated implant did not further reduce bacterial growth significantly compared with systemic or local antibiotic application alone. Combined local and systemic therapy reduced serum haptoglobin significantly after day 7, 28 and 42 whereas systemic application alone did not compare to controls. CONCLUSIONS: Systemic perioperative and implant-associated application of antibiotics were both comparably effective to treat implant-associated infections whereas the combined antibiotic therapy further reduced systemic signs of infection time dependent.

Improvement in outcomes after implantation of a novel polyurethane meniscal scaffold for the treatment of medial meniscus deficiency.

PURPOSE: Meniscal injury resulting in segmental loss of meniscal tissue is a major risk factor for the development of osteoarthritis. Tissue engineering strategies have provided scaffolds for meniscal regeneration in order to establish a treatment option for patients with limited opportunities for meniscal reconstruction. The purpose of this study was to assess the clinical and magnetic resonance imaging (MRI) results 2 years after implantation of a polyurethane scaffold for chronic segmental medial meniscus deficiency following partial medial meniscectomy. METHODS: Eighteen patients were treated with arthroscopic implantation of an ActiFit(®) (Orteq Sports Medicine) polyurethane meniscal scaffold for meniscus deficiency of the medial meniscus. Patients were followed up at 6, 12, and 24 months. Clinical outcome was assessed using patient-reported outcome scores (KOOS, KSS, UCLA activity scale, VAS for pain). Radiological outcome was assessed using MRI at 6, 12, and 24 months by evaluating scaffold morphology, scaffold integration, and additional joint injury, as well as joint inflammation. RESULTS: Eighteen patients with a median age of 32.5 years (range 17-49) were enrolled. Statistically significant improvements were present in all patients, but one at 2 years compared to baseline in all categories. Complete resorption of the scaffold occurred in one patient representing a failure to treatment. MRI showed abnormal signal intensity of the scaffold when compared to residual meniscal tissue but without synovitis or joint inflammation. Extrusion of the scaffold was present in four patients. No correlation between scaffold extrusion and clinical outcome was observed. CONCLUSION: Arthroscopic implantation of a polyurethane meniscal scaffold in patients with chronic segmental medial meniscus deficiency is not only a safe procedure but leads to good clinical results at a 2-year follow-up. Scaffold extrusion did not appear to affect clinical outcome. LEVEL OF EVIDENCE: IV.

Short-term follow up after implantation of a cell-free collagen type I matrix for the treatment of large cartilage defects of the knee.

PURPOSE: Although there are various new scaffold-based techniques for cartilage regeneration it remains unclear up to which defect size they can be used. The present study reports of a cell-free collagen type I gel matrix for the treatment of large cartilage defects of the knee after a two-year follow-up. METHODS: Twenty-eight patients with a mean cartilage defect size of 3.71 ± 1.93 cm² were treated with a cell-free collagen type I gel matrix (CaReS-1S®, Arthro Kinetics AG, Krems/Donau, Austria) via a mini-arthrotomy. Clinical outcome was assessed preoperatively and six weeks as well as six, 12 and 24 months after surgery using various clinical outcome scores (IKDC, Tegner, KOOS, VAS). Cartilage regeneration was evaluated via MRI using the MOCART score. RESULTS: Seventeen male and 11 female patients with a mean age of 34.6 years were included in this study. Significant pain reduction (VAS) could be noted after six weeks already. Patient activity (IKDC, Tegner) could be significantly improved from 12 months on and nearly reached reported pre-operative values. All subject categories of the KOOS except for symptom (swelling) showed significant improvements throughout the study. Constant significant improvements of the mean MOCART score were observed from 12 months on. MR images did not yield any signs of infection or synovitis. After 24 months a complete defect filling could be noted in 24 out of 28 cases with a mainly smooth surface, complete integration of the border zone and homogenous structure of the repaired tissue. CONCLUSION: Cell-free collagen type I matrices appear to be a safe and suitable treatment option even for large cartilage defects of the knee. Results of this study were comparable to the better-established findings for small cartilage defects. Mid- and long-term results will be needed to see if clinical and MR-tomographic outcome can be maintained beyond 24 months.

Coating with a novel gentamicinpalmitate formulation prevents implant-associated osteomyelitis induced by methicillin-susceptible Staphylococcus aureus in a rat model.

PURPOSE: Implant-associated osteomyelitis still represents a demanding challenge due to unfavourable biological conditions, bacterial properties and incremental resistance to antibiotic treatment. Therefore different bactericide or bacteriostatic implant coatings have been developed recently to control local intramedullary infections. Controlled local release of gentamicin base from a highly lipophilic gentamicin palmitate compound achieves extended intramedullary retention times and thus may improve its bactericide effect. METHODS: Forty male Sprague-Dawley rats were divided into two groups receiving an intramedullary femoral injection of 10(2) colony-forming units (CFU) of a common methicillin susceptible Staphylococcus aureus strain (MSSA Rosenbach) and either an uncoated femur nail (Group I) or a nail coated with gentamicin palmitate (Group II). Animals were observed for 28 and 42 days. Serum haptoglobin and relative weight gain were assessed as well as rollover cultures of explanted femur nails and histological scores of periprosthetic infection in dissected femurs. RESULTS: Implants coated with gentamicin palmitate significantly reduced periprosthetic bacterial growth as well as signs of systemic inflammation compared with uncoated implants. CONCLUSIONS: Gentamicin palmitate appears to be a viable coating for the prevention of implant-associated infections. These findings will have to be confirmed in larger animal models as well as in clinical trials.

Patellofemoral osteoarthritis after Insall's proximal realignment for recurrent patellar dislocation.

PURPOSE: The aim of the present study was to retrospectively investigate the development of patellofemoral osteoarthritis after the historical Insall's proximal realignment for patellar stabilisation in patients with recurrent patellar dislocation. Furthermore, risk factors for recurrent patellar dislocation and for patellofemoral osteoarthritis development were evaluated. METHODS: Forty-two patients underwent patellofemoral stabilising surgery by the historic Insall's proximal realignment; they were evaluated with a mean follow-up period of 52 months. Plain radiography was used to document osteoarthritic changes by using the Iwano classification. MRIs obtained at the latest follow-up were evaluated for patellofemoral cartilage lesions. Univariate and multivariate logistic regression analyses were performed to evaluate the influence of trochlear dysplasia, tibial tubercle-trochlear groove distance and patellar height on redislocation. Pearson's χ (2) and the Spearman's correlation tests were used to assess a possible correlation between trochlear dysplasia and patellar dislocation, as well as between instability and development of patellofemoral osteoarthritis. RESULTS: At the latest follow-up, plain radiographs showed a significant increase in patellofemoral osteoarthritis (grades II-IV according to the Iwano classification) in 18 patients (43%) compared with 4 patients (10%) at the time of surgery (P = 0.001). Patellofemoral cartilage lesions (grades II-IV) were detected in 18 patients (43 %) on MRI. Nine patients (21%) had at least one incidence of redislocation at follow-up. Estimated redislocation-associated risk factors could not be determined. Trochlear dysplasia had a significant impact on patellofemoral osteoarthritis development (P = 0.001), whereas recurrent patellar instability had none (n.s.). CONCLUSION: Insall's proximal realignment technique leads to a significant progression of patellofemoral osteoarthritis. No risk factors for redislocation could be found; however, the presence of trochlear dysplasia did correlate with patellofemoral osteoarthritis. LEVEL OF EVIDENCE: IV.