Analysis of postoperative complications 5 years after osteosynthesis of patella fractures-a retrospective, multicenter cohort study.

PURPOSE: The study aims to investigate the influence of patient- and fracture-specific factors on the occurrence of complications after osteosynthesis of patella fractures and to compare knee joint function, activity, and subjective pain levels after a regular postoperative course and after complications in the medium term. METHODS: This retrospective, multicenter cohort study examined patients who received surgery for patella fracture at level 1 trauma centers between 2013 and 2018. Patient demographics and fracture-specific variables were evaluated. Final follow-up assessments included patient-reported pain scores (NRS), subjective activity and knee function scores (Tegner Activity Scale, Lysholm score, IKDC score), complications, and revisions. RESULTS: A total of 243 patients with a mean follow-up of 63.4 ± 21.3 months were included. Among them, 66.9% of patients underwent tension band wiring (TBW), 19.0% received locking plate osteosynthesis (LPO), and 14.1% underwent screw osteosynthesis (SO). A total of 38 patients (15.6%) experienced complications (TBW: 16.7%; LPO: 15.2%; SO: 11.8%). Implant-related complications of atraumatic fragment dislocation and material insufficiency/dislocation, accounted for 50% of all complications, were significantly more common after TBW than LPO (p = 0.015). No patient-specific factor was identified as a general cause for increased complications. Overall, particularly following complications such as limited range of motion or traumatic refracture, functional knee scores were significantly lower and pain levels were significantly higher at the final follow-up when a complication occurred. Implant-related complications, however, achieved functional scores comparable to a regular postoperative course without complications after revision surgery. CONCLUSION: The present study demonstrated that implant-related complications occurred significantly more often after TBW compared to LPO. The complication rates were similar in all groups.

S2k Guideline for Tibial Plateau Fractures - Classification, Diagnosis, and Treatment. / S2k-Leitlinie Tibiakopffraktur ­ Klassifikation, Diagnostik und Therapie.

Tibial plateau fractures are mostly complex and surgically demanding joint fractures, which require a comprehensive understanding of the fracture morphology, ligamentous and neurovascular injuries, as well as the diagnostic and therapeutic options for an optimal clinical outcome. Therefore, a standardised and structured approach is required. The success of the treatment of tibial plateau fractures relies on the interdisciplinary cooperation between surgical and conservative physicians in an outpatient and inpatient setting, physical therapists, patients and service providers (health insurance companies, statutory accident insurance, pension providers). On behalf of the German Society for Orthopaedics and Trauma Surgery (DGOU), the German Trauma Society (DGU) and the Society for Arthroscopy and Joint Surgery (AGA), under the leadership of the Fracture Committee of the German Knee Society (DKG), a guideline for tibial plateau fractures was created, which was developed in several voting rounds as part of a Delphi process. Based on the current literature, this guideline is intended to make clear recommendations and outline the most important treatment steps in diagnostics, therapy and follow-up treatment. Additionally, 25 statements were revised by the authors in several survey rounds using the Likert scale in order to reach a final consensus.

Age-Related Changes in the Microvascular Density of the Human Meniscus.

BACKGROUND: The microvascular anatomy of the meniscus of the human knee is regarded as a crucial factor in the injury response. Previous studies have investigated the zone-dependent distribution pattern, but no quantitative data exist on vascular density and its age-related changes. HYPOTHESIS/PURPOSE: The aim of the present study was to histologically analyze the vascular anatomy of the meniscus as a function of age. It was hypothesized that vascular density would decrease with increasing age. STUDY DESIGN: Descriptive laboratory study. METHODS: Human menisci were retrieved from patients who underwent tumor resection or who received total knee replacement because of osteoarthritis. A total of 51 menisci were collected from 28 patients over 9 years (mean age, 25.6 ± 20.4 years; range 3-79 years). Immunohistological staining (alpha-smooth muscle actin) in combination with serial sections and standardized software-based contrast detection were used for the quantitative analysis. Data were analyzed using multiple t tests and the analysis of variance for trends, with a statistical significance level of P < .05. RESULTS: The overall vascular density in the meniscus was lower in the 61- to 80-year age group than in the age groups of 0 to 10, 11 to 20, and 21 to 30 years (P < .01). A negative linear trend was detected with increasing age (slope, -0.007; P = .016). Within the red-white (RW) zone, a low vessel density was detected for the age groups of 0 to 10 and 11 to 20 years. Beyond these age groups, no vasculature was found in the RW zone. For the white-white (WW) zone, no vessel formations were noted in any age group. Almost 95% of the vessels in the meniscus were located in the capsule. CONCLUSION: This study reports quantitative histological data for microvascular anatomy as a function of age in a broad cohort of human knee menisci. The overall vascular density decreased with increasing age. No vessel formations were detected in the RW and WW zones after adolescence. Additionally, the capsule is far more densely vascularized than any other part of the meniscus. CLINICAL RELEVANCE: Vascular density might be an additional factor to consider, along with tear location and patient age, for future treatment options.

Medial collateral ligament reconstruction graft isometry is effected by femoral position more than tibial position.

PURPOSE: The purpose of this study was to examine the length change patterns of the native medial structures of the knee and determine the effect on graft length change patterns for different tibial and femoral attachment points for previously described medial reconstructions. METHODS: Eight cadaveric knee specimens were prepared by removing the skin and subcutaneous fat. The sartorius fascia was divided to allow clear identification of the medial ligamentous structures. Knees were then mounted in a custom-made rig and the quadriceps muscle and the iliotibial tract were loaded, using cables and hanging weights. Threads were mounted between tibial and femoral pins positioned in the anterior, middle, and posterior parts of the attachment sites of the native superficial medial collateral ligament (sMCL) and posterior oblique ligament (POL). Pins were also placed at the attachment sites relating to two commonly used medial reconstructions (Bosworth/Lind and LaPrade). Length changes between the tibiofemoral pin combinations were measured using a rotary encoder as the knee was flexed through an arc of 0-120°. RESULTS: With knee flexion, the anterior fibres of the sMCL tightened (increased in length 7.4% ± 2.9%) whilst the posterior fibres slackened (decreased in length 8.3% ± 3.1%). All fibre regions of the POL displayed a uniform lengthening of approximately 25% between 0 and 120° knee flexion. The most isometric tibiofemoral combination was between pins placed representing the middle fibres of the sMCL (Length change = 5.4% ± 2.1% with knee flexion). The simulated sMCL reconstruction that produced the least length change was the Lind/Bosworth reconstruction with the tibial attachment at the insertion of the semitendinosus and the femoral attachment in the posterior part of the native sMCL attachment side (5.4 ± 2.2%). This appeared more isometric than using the attachment positions described for the LaPrade reconstruction (10.0 ± 4.8%). CONCLUSION: The complex behaviour of the native MCL could not be imitated by a single point-to-point combination and surgeons should be aware that small changes in the femoral MCL graft attachment position will significantly effect graft length change patterns. Reconstructing the sMCL with a semitendinosus autograft, left attached distally to its tibial insertion, would appear to have a minimal effect on length change compared to detaching it and using the native tibial attachment site. A POL graft must always be tensioned near extension to avoid capturing the knee or graft failure.

The Popliteus Bypass provides superior biomechanical properties compared to the Larson technique in the reconstruction of combined posterolateral corner and posterior cruciate ligament injury.

PURPOSE: This study aimed to compare the biomechanical properties of the popliteus bypass against the Larson technique for the reconstruction of a combined posterolateral corner and posterior cruciate ligament injury. METHODS: In 18 human cadaver knees, the kinematics for 134 N posterior loads, 10 Nm varus loads, and 5 Nm external rotational loads in 0°, 20°, 30°, 60,° and 90° of knee flexion were measured using a robotic and optical tracking system. The (1) posterior cruciate ligament, (2) meniscofibular/-tibial fibers, (3) popliteofibular ligament (PFL), (4) popliteotibial fascicle, (5) popliteus tendon, and (6) lateral collateral ligament were cut, and the measurements were repeated. The knees underwent posterior cruciate ligament reconstruction, and were randomized into two groups. Group PB (Popliteus Bypass; n = 9) underwent a lateral collateral ligament and popliteus bypass reconstruction and was compared to Group FS (Fibular Sling; n = 9) which underwent the Larson technique. RESULTS: Varus angulation, posterior translation, and external rotation increased after dissection (p < 0.01). The varus angulation was effectively reduced in both groups and did not significantly differ from the intact knee. No significant differences were found between the groups. Posterior translation was reduced by both techniques (p < 0.01), but none of the groups had restored stability to the intact state (p < 0.02), with the exception of group PB at 0°. No significant differences were found between the two groups. The two techniques revealed major differences in their abilities to reduce external rotational instability. Group PB had less external rotational instability compared to Group FS (p < 0.03). Only Group PB had restored rotational instability compared to the state of the intact knee (p < 0.04) at all degrees of flexion. CONCLUSION: The popliteus bypass for posterolateral reconstruction has superior biomechanical properties related to external rotational stability compared to the Larson technique. Therefore, the popliteus bypass may have a positive influence on the clinical outcome. This needs to be proven through clinical trials.

Trends in arthrodeses and total joint replacements in Foot and Ankle surgery in Germany during the past decade-Back to the fusion?

BACKGROUND: The goal of this study was to analyze trends in Foot and Ankle surgery in Germany during the past ten years. METHODS: Data of the German Federal Statistical Office from 2008 until 2018 were screened. We focused on the analysis of fusions and total joint replacements. RESULTS: The total amount of the surgeries increased (+39.5%). Especially fusions like arthrodesis of the ankle (+31%) and of the MTP-1 joint (+77%) were on the rise. In 2017 60% of ankle arthrodesis were conducted in men, while 69% of MTP-1 arthrodesis were performed in women. The amount of joint replacements showed a decline during the last decade, in TAR (-39%) and in the MTP-1 (-48%). Regarding the patients age while undergoing a TAR, we observed a shift of the peak age group from 65 to 70 years in 2008 towards 55-60 years in 2017. CONCLUSION: Our study represents actual health care reality in Germany and shows a constant increase of ankle arthritis surgeries in the last decade, while there was a massive shift regarding the ratio of TAR in favour of fusion procedures.

[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.

Bone metabolism is a key factor for clinical outcome of tibial plateau fractures.

PURPOSE: Given that tibial plateau fractures (TPF) are rare, they may pose a challenge to the treating surgeon due to their variety of complex fracture patterns. Numerous studies have identified potential fracture-specific, surgery-related, and patient-related risk factors for impaired patient outcomes. However, reports on the influence of bone metabolism on functional outcomes are missing. METHODS: In a retrospective multicenter cohort study, 122 TPF of 121 patients were analyzed with respect to radiological and clinical outcomes (Rasmussen) with a mean follow-up of 35.7 ± 24.9 months. The risk factor assessment included bone metabolism-affecting comorbidities and medication. RESULTS: The findings showed that 95.9% of the patients reported a good-to-excellent clinical outcome, and 97.4% reported a good-to-excellent radiological outcome. Logistic regression revealed that potentially impaired bone metabolism (IBM) was an independent risk factor for the clinical (p = 0.016) but not the radiological outcome (Table 4). Patients with 41-type B fractures and a potential IBM had a seven times higher risk to present a fair-to-poor clinical outcome [OR 7.45, 95 CI (4.30, 12.92)]. The most common objective impairment was a limited range of motion in 16.4% of the patients, especially in 41-type C fractures (p = 0.06). The individual failure analysis additionally identified surgery-related options for improvement. CONCLUSION: This study demonstrated that potential IBM was an independent risk factor for a poor-to-fair clinical outcome.

Repair With Dynamic Intraligamentary Stabilization Versus Primary Reconstruction of Acute Anterior Cruciate Ligament Tears: 2-Year Results From a Prospective Randomized Study.

BACKGROUND: Anterior cruciate ligament (ACL) repair has once again become a focus of research because of the development of new techniques. PURPOSE/HYPOTHESIS: The purpose was to compare the functional results and recurrent instability rates in patients undergoing ACL repair with dynamic intraligamentary stabilization (DIS) versus primary ACL reconstruction (ACLR) for acute isolated ACL tears. The hypothesis was that functional results and knee joint stability after ACL repair with DIS would be comparable with that after ACLR. STUDY DESIGN: Randomized clinical trial; Level of evidence, 1. METHODS: A total of 85 patients with acute ACL tears were randomized to undergo either ACL repair with DIS or primary ACLR. The preinjury activity level and function were recorded. Follow-up examinations were performed at 6 weeks and 6, 12, and 24 months postoperatively. Anterior tibial translation (ATT) was evaluated using Rolimeter testing. The Tegner activity scale, International Knee Documentation Committee (IKDC) subjective form, and Lysholm knee scoring scale scores were obtained. Clinical failure was defined as ΔATT >3 mm in combination with subjective instability. Recurrent instability and other complications were recorded. RESULTS: There were 83 patients (97.6%) who were successfully followed until 2 years. ATT was significantly increased in the DIS group compared with the ACLR group (ΔATT, 1.9 vs 0.9 mm, respectively; P = .0086). A total of 7 patients (16.3%) in the DIS group had clinical failure and underwent single-stage revision. In the ACLR group, 5 patients (12.5%) had failure of the reconstruction procedure; 4 of these patients required 2-stage revision. The difference in the failure rate was not significant (P = .432). There were 4 patients (3 in the DIS group and 1 in the ACLR group) who showed increased laxity (ΔATT >3 mm) without subjective instability and did not require revision. Recurrent instability was associated with young age (<25 years) and high Tegner scores (>6) in both groups. No significant differences between ACL repair with DIS and ACLR were found for the Tegner, IKDC, and Lysholm scores at any time. CONCLUSION: Whereas ATT measured by Rolimeter testing was significantly increased after ACL repair with DIS, clinical failure was similar to that after ACLR. In addition, functional results after ACL repair with DIS for acute tears were comparable with those after ACLR. The current study supports the use of ACL repair with DIS as an option to treat acute ACL tears. REGISTRATION: DRKS00015466 (German Clinical Trials Register).

[Clinical examination of the knee]. / Klinische Untersuchung des Knies.

The clinical examination of the knee joint represents a great challenge as well as a great opportunity. In particular, ligamentous injuries are understood better despite their complexity and thus treated in a more differentiated way. A purely radiologically based diagnosis is only possible to a limited extent, especially for chronic injuries. Therefore, complex ligament injuries can be diagnosed with the aid of a differentiated clinical examination. This article gives an overview of the most important examination techniques of the knee joint, with which the decisive analysis of acute or chronic injuries and overuse syndromes of the knee can be carried out. Particularly in the field of ligament instability, this article provides a practical guide for the differentiated examination of complex rotational instability of the knee joint. In addition, the most important patellar and meniscal examination techniques are described.

Soft Tissue Fixation Strategies of Human Quadriceps Tendon Grafts: A Biomechanical Study.

PURPOSE: To evaluate the effects of different stitching methods and suture diameters on the graft fixation of soft tissue human quadriceps tendon grafts for anterior cruciate ligament (ACL) reconstruction. METHODS: The Krackow locking stitch (K), whipstitch (W), and baseball stitch (B) were combined with either a 2× no. 2 (#2) or a 1× no. 5 (#5) braided composite suture for graft fixation of 36 human quadriceps tendons in 6 groups. Biomechanical testing was performed using a cyclic protocol with loads between 0 and 100 N. The maximum load until failure, cyclic elongation, and failure mode were recorded. RESULTS: The highest mean maximum load to failure was observed in the 2 Krackow stitch groups. The K#2 group had significantly higher load to failure values compared with those of the W#2 and B#2 groups (K#2, 553 ± 82 N vs W#2, 392 ± 107 N, P = .0349; K#2 vs B#2 366 ± 118 N, P = .0129). The mean cyclic elongation was lowest in the Krackow groups (K#2, 10.59 ± 2.63 mm; K#5, 13.66 ± 2.3 mm). The regular failure mode was the rupture of the suture for the Krackow stitch (8 of 12) and suture pullout for the whipstitch (11 of 12) and baseball stitch groups (12 of 12). CONCLUSIONS: The double Krackow stitch with no. 2 braided composite suture exhibits a high maximum load to failure combined with a low amount of elongation in a biomechanical study for human quadriceps tendon soft tissue graft fixation. Unlike the whipstitch and the baseball stitch, it can solidly prevent suture pullout. CLINICAL RELEVANCE: A safe soft tissue graft fixation technique is especially important for quadriceps tendon grafts with their laminar anatomical structure and physiologically varying diameter. Unlike other grafts for ACL replacement, it fully relies on the soft tissue suture fixation to resist the pullout force.

Dynamic Restraints of the Medial Side of the Knee: The Semimembranosus Corner Revisited.

BACKGROUND: Little is known about the dynamic restraints of the semimembranosus muscle (SM). PURPOSE AND HYPOTHESIS: The goal of the present study was to elucidate the role of (1) passive and (2) active restraints to medial-side instability and to analyze (3) the corresponding tightening of the posteromedial structures by loading the SM. It was hypothesized that points 1 to 3 will significantly restrain medial knee instability. This will aid in understanding the synergistic effect of the semimembranosus corner. STUDY DESIGN: Controlled laboratory study. METHODS: Nine knees were tested in a 6 degrees of freedom robotic setup and an optical tracking system. External rotation (ER; 4 N·m), internal rotation (4 N·m), anteromedial rotation (4-N·m ER and 89-N anterior tibial translation), and valgus rotation (8 N·m) were applied at 0°, 30°, 60°, and 90°, with and without an SM load of 75 N. Sequential cutting of the medial collateral ligament and posterior oblique ligament was then performed. At the intact state of the knee and after each cut, the aforementioned simulated laxity tests were performed. RESULTS: The medial collateral ligament was found to be the main passive stabilizer to ER and anteromedial rotation, resulting in 9.3° ± 6.8° ( P < .05), 8.1° ± 3.6° ( P < .05), and 7.6° ± 4.2° ( P < .05) at 30°, 60°, and 90°, respectively. Conversely, after the posterior oblique ligament was cut, internal rotation instability increased significantly at early flexion angles (9.3° ± 3.2° at 0° and 5.2° ± 1.1 at 30°). Loading the SM had an overall effect on restraining ER ( P < .001) and anteromedial rotation ( P < .001). This increased with flexion angle and sectioning of the medial structures and resulted in a pooled 2.8° ± 1.7° (not significant), 5.4° ± 2° ( P < .01), 7.5° ± 2.8° ( P < .001), and 8.3° ± 4.4° ( P < .001) at 0°, 30°, 60°, and 90° when compared with the unloaded state. CONCLUSION: The SM was found to be a main active restraint to ER and anteromedial rotation, especially at higher flexion angles and in absence of the main passive medial restraints. The calculated tensioning effect was small in all flexion angles for all simulated laxity tests. CLINICAL RELEVANCE: A complete semimembranosus avulsion may indicate severe medial knee injury, and refixation should be considered in multiligament injury.

Changes in gait pattern and early functional results after ACL repair are comparable to those of ACL reconstruction.

PURPOSE: Dynamic intraligamentary stabilization (DIS) has been introduced as a new technique to repair the torn anterior cruciate ligament (ACL) and to restore knee joint kinematics after an acute ACL tear. Aim of the present study was to compare the early post-operative activity, restoration of gait pattern and functional results after DIS in comparison with primary ACL reconstruction (ACLR) for acute ACL tears. It was hypothesized that functional results, post-operative activity and changes in gait pattern after DIS are comparable to those after ACLR. METHODS: Sixty patients with acute ACL tears were included in this study and underwent either DIS or ACLR with an anatomic semitendinosus autograft in a randomized manner. Patients were equipped with an accelerometric step counter for the first 6 weeks after surgery in order to monitor their early post-operative activity. 3D gait analysis was performed at 6 weeks and 6 months after surgery. Temporal-spatial, kinematic and kinetic parameters were extracted and averaged for each subject. Functional results were recorded at 6 weeks, 6 months and 12 months after surgery using the Tegner activity scale, International Knee Documentation Committee score and Lysholm score. RESULTS: Patients who underwent DIS showed an increased early post-operative activity with significant differences at week 2 and 3 (p = 0.0241 and 0.0220). No significant differences between groups were found for knee kinematic and kinetic parameters or the functional scores at any time of the follow-up. Furthermore, the difference in anterior tibial translation was not significantly different between the two groups (n.s.). CONCLUSION: Early functional results and changes in gait pattern after DIS are comparable to those of primary ACLR. Therefore, ACL repair may be an alternative to ACLR in this cohort of patients. LEVEL OF EVIDENCE: I.

Partial proximal tibia fractures.

Partial tibial plateau fractures may occur as a consequence of either valgus or varus trauma combined with a rotational and axial compression component.High-energy trauma may result in a more complex and multi-fragmented fracture pattern, which occurs predominantly in young people. Conversely, a low-energy mechanism may lead to a pure depression fracture in the older population with weaker bone density.Pre-operative classification of these fractures, by Müller AO, Schatzker or novel CT-based methods, helps to understand the fracture pattern and choose the surgical approach and treatment strategy in accordance with estimated bone mineral density and the individual history of each patient.Non-operative treatment may be considered for non-displaced intra-articular fractures of the lateral tibial condyle. Intra-articular joint displacement ⩾ 2 mm, open fractures or fractures of the medial condyle should be reduced and fixed operatively. Autologous, allogenic and synthetic bone substitutes can be used to fill bone defects.A variety of minimally invasive approaches, temporary osteotomies and novel techniques (e.g. arthroscopically assisted reduction or 'jail-type' screw osteosynthesis) offer a range of choices for the individual and are potentially less invasive treatments.Rehabilitation protocols should be carefully planned according to the degree of stability achieved by internal fixation, bone mineral density and other patient-specific factors (age, compliance, mobility). To avoid stiffness, early functional mobilisation plays a major role in rehabilitation. In the elderly, low-energy trauma and impression fractures are indicators for the further screening and treatment of osteoporosis. Cite this article: EFORT Open Rev 2017;2. DOI: 10.1302/2058-5241.2.160067. Originally published online at www.efortopenreviews.org.

Kinematics of Different Components of the Posterolateral Corner of the Knee in the Lateral Collateral Ligament-intact State: A Human Cadaveric Study.

PURPOSE: To determine the static stabilizing effects of different anatomical structures of the posterolateral corner (PLC) of the knee in the lateral collateral ligament (LCL)-intact state. METHODS: Thirteen fresh-frozen human cadaveric knees were dissected and tested using an industrial robot with an optical tracking system. Kinematics were determined for 134 N anterior/posterior loads, 10 N m valgus/varus loads, and 5 N m internal/external rotatory loads in 0°, 20°, 30°, 60°, and 90° of knee flexion. The PLC structures were dissected and consecutively released: (I) intact knee joint, (II) with released posterior cruciate ligament (PCL), (III) popliteomeniscal fibers, (IV) popliteofibular ligament, (V) arcuat and popliteotibial fibers, (VI) popliteus tendon (PLT), and (VII) LCL. Repeated-measures analysis of variance was performed with significance set at P < .05. RESULTS: After releasing the PCL, posterior tibial translation increased by 5.2 mm at 20° to 9.4 mm at 90° of joint flexion (P < .0001). A mild 1.8° varus instability was measured in 0° of flexion (P = .0017). After releasing the PLC structures, posterior tibial translation further increased by 2.9 mm at 20° to 5.9 mm at 90° of flexion (P < .05) and external rotation angle increased by 2.6° at 0° to 7.9° at 90° of flexion (P < .05, vs II). Varus stability did not decrease. Mild differences between states V and VI were found in 60° and 90° external rotation tests (2.1° and 3.1°; P < .05). CONCLUSIONS: The connecting ligaments/fibers to the PLT act as a primary static stabilizer against external rotatory loads and a secondary stabilizer against posterior tibial loads (when PCL is injured). After releasing these structures, most static stabilizing function of the intact PLT is lost. The PLC has no varus-stabilizing function in the LCL-intact knee. CLINICAL RELEVANCE: Anatomy and function of these structures for primary and secondary joint stability should be considered for clinical diagnostics and when performing surgery in the PLC.

Anterior Cruciate Ligament Soft Tissue Graft Fixation in the Elderly: Is There a Reason to Use Interference Screws? A Human Cadaver Study.

PURPOSE: To analyze the ultimate failure load, yield load, stiffness, and cyclic resistance of different anterior cruciate ligament (ACL) soft tissue graft fixation techniques in osteopenic bone. METHODS: In this study, 24 fresh-frozen human cadaveric tibiae (mean age 82.6 years; range 56-96; 6 male and 6 female donors) were used. Quantitative computed tomography was performed to match bone density. Looped porcine flexor tendon grafts were chosen as ACL graft substitutes for tibial graft fixation techniques (n = 8 each): (1) hybrid fixation with an interference screw and extracortical button fixation; (2) extracortical button fixation; and (3) interference screw fixation. In single cycle mode, constructs were loaded to failure to evaluate stiffness, yield load, and maximum load. In cyclic testing, 2,000 cycles (25-100 N) were applied followed by loading to failure. A 1-way analysis of variance was performed with significance set at P = .05. RESULTS: Hybrid fixation resulted in significantly higher yield load (283.4 ± 86.19 N; P = .0037) and maximum load (407.9 ± 102.3 N; P = .0026) than interference screw fixation (yield load 176.4 ± 26.03, max load 231.8 ± 94.06 N) in elderly bone. Yield load after extracortical button fixation (252.9 ± 41.97 N; P = .0286) was also higher than that after interference screw fixation, but stiffness (18.98 ± 9.154 N/mm; P = .0041) was less than that after hybrid fixation (37.28 ± 13.53 N/mm). Of 8 specimens in the interference screw group, 7 did not survive 2,000 cycles and failed by graft slippage, whereas all other specimens in both other groups survived. CONCLUSIONS: Tibial hybrid fixation of ACL soft tissue grafts provides less vertical graft movement than extracortical button fixation and higher primary failure loads than interference screw fixation in elderly bone. CLINICAL RELEVANCE: In this elderly human joint in vitro model, tibial hybrid fixation provides biomechanical advantages over other techniques. Graft fixation with only an interference screw should be avoided in osteopenic bone.

Trends and incidences of ligament-surgeries and osteotomies of the knee: an analysis of German inpatient records 2005-2013.

INTRODUCTION: In Germany most surgical procedures of the ligaments of the knee and correcting osteotomies of the knees are performed within an inpatient setting. The purpose of this study was to analyze the available data to assess epidemiological trends and incidences in inpatient knee joint surgery. MATERIALS AND METHODS: Approximately 154 million anonymized DRG inpatient records were collected by the German Federal Statistical Office between 2005 and 2013. These data were screened and analyzed for knee joint surgical ligamental procedures and osteotomies. RESULTS: Anterior cruciate ligament reconstruction (ACLR) or repair had a high incidence (46 per 100,000 persons/year). In addition, the most frequent grafts included hamstring tendon (90%) and the patellar tendon (6.3%) autografts (2013). Peak age group for ACLR was 15-20 years (14.5%) for female and 20-25 years (23.6%) for male patients, while there was a second peak in the age group 45-50 years (13.8%) for female patients. Male patients had a higher risk for receiving ACLR (RR 1.96; 95% CI 1.92-2.00) and for receiving valgizing high tibial osteotomy (RR 2.43; 95% CI 2.27-2.61). Females had a higher risk for receiving varizing distal femur osteotomy (RR 1.89; 95% CI 1.58-2.26). CONCLUSION: There are growing trends for joint- and activity-preserving procedure in the middle-aged patients. The knowledge of the trends and incidences related to these procedures may help to validate and discuss the results of clinical and register studies.

Knee joint kinematics after dynamic intraligamentary stabilization: cadaveric study on a novel anterior cruciate ligament repair technique.

PURPOSE: Dynamic intraligamentary stabilization (DIS) has been introduced for the repair of acute anterior cruciate ligament (ACL) tears as an alternative to delayed reconstruction. The aim of the present study was to compare knee joint kinematics after DIS to those of the ACL-intact and ACL-deficient knee under simulated Lachman/KT-1000 and pivot-shift tests. We hypothesized that DIS provides knee joint kinematics equivalent to an intact ACL. METHODS: With the use of a robotic knee simulator, knee kinematics were determined in simulated Lachman/KT-1000 and pivot-shift tests at 0°, 15°, 30°, 60°, and 90° of flexion in eight cadaveric knees under the following conditions: (1) intact ACL, (2) ACL deficiency, (3) DIS with a preload of 60 N, and (4) DIS with a preload of 80 N. Statistical analyses were performed using two-factor repeated-measures analysis of variance. The significance level was set at a p value of <0.05. RESULTS: After DIS with a preload of either 60 N or 80 N, the anterior translation was significantly reduced in the simulated Lachman/KT-1000 and pivot-shift tests when compared to the ACL-deficient knee (p < 0.05). No significant differences were observed between the DIS reconstruction with a preload of 80 N and the intact ACL with regard to anterior laxity in either test. However, DIS with a preload of only 60 N was not able to restore knee joint kinematics to that of an intact knee in all degrees of flexion. CONCLUSION: DIS with a preload of 80 N restores knee joint kinematics comparable to that of an ACL-intact knee and is therefore capable of providing knee joint stability during ACL healing. DIS therefore provides a new technique for primary ACL repair with superior biomechanical properties in comparison with other techniques that have been described previously, although further clinical studies are required to determine its usefulness in clinical settings.

Should the Ipsilateral Hamstrings Be Used for Anterior Cruciate Ligament Reconstruction in the Case of Medial Collateral Ligament Insufficiency? Biomechanical Investigation Regarding Dynamic Stabilization of the Medial Compartment by the Hamstring Muscles.

BACKGROUND: Semitendinosus and gracilis muscles are frequently harvested for autologous tendon grafts for cruciate ligament reconstruction. This study investigated the joint-stabilizing effects of these hamstring muscles in cases of insufficiency of the medial collateral ligament (MCL). HYPOTHESES: First, both the semitendinosus and gracilis muscles can actively stabilize the joint against valgus moments in the MCL-deficient knee. Second, the stabilizing influence of these muscles decreases with an increasing knee flexion angle. STUDY DESIGN: Controlled laboratory study. METHODS: The kinematics was examined in 10 fresh-frozen human cadaveric knees using a robotic/universal force moment sensor system and an optical tracking system. The knee kinematics under 5- and 10-N·m valgus moments were determined in the different flexion angles of the (1) MCL-intact and (2) MCL-deficient knee using the following simulated muscle loads: (1) 0-N (idle) load, (2) 200-N semitendinosus (ST) load, and (3) 280-N (200/80-N) combined semitendinosus/gracilis (STGT) load. RESULTS: Cutting the MCL increased the valgus angle under all tested conditions and angles compared with the MCL-intact knee by 4.3° to 8.1° for the 5-N·m valgus moment and 6.5° to 11.9° for the 10-N·m valgus moment ( P < .01). The applied 200-N simulated ST load reduced the valgus angle significantly at 0°, 10°, 20°, and 30° of flexion under 5- and 10-N·m valgus moments ( P < .05). At 0°, 10°, and 20° of flexion, these values were close to those for the MCL-intact joint under the respective moments (both P > .05). The combined 280-N simulated STGT load significantly reduced the valgus angle in 0°, 10°, and 20° of flexion under 5- and 10-N·m valgus moments ( P < .05) to values near those for the intact joint (5 N·m: 0°, 10°; 10 N·m: 0°, 10°, 20°; P > .05). In 60° and 90° of flexion, ST and STGT loads did not decrease the resulting valgus angle of the MCL-deficient knee without hamstring loads ( P > .05 vs deficient; P = .0001 vs intact). CONCLUSION: In this human cadaveric study, semitendinosus and gracilis muscles successfully stabilize valgus moments applied to the MCL-insufficient knee when the knee is near extension. CLINICAL RELEVANCE: In the valgus-unstable knee, these data suggest that the hamstring muscles should be preserved in (multi-) ligament surgery when possible.

Intra-articular tibial plateau fracture characteristics according to the "Ten segment classification".

BACKGROUND: Currently existing classifications of tibial plateau fractures do not help to guide surgical strategy. Recently, a segment-based mapping of the tibial plateau has been introduced in order to address fractures with a fracture-specific surgical approach. The goal of the present study was to analyze incidence and fracture specifics according to a new 10-segment classification of the tibial plateau. METHODS: A total of 242 patients with 246 affected knees were included (124 females, 118 males, mean age 51.9±16.1years). Fractures were classified according to the OTA/AO classification. Fracture pattern was analyzed with respect to a 10-segment classification based on CT imaging of the proximal tibial plateau 3cm below the articular surface. RESULTS: 161 Patients suffered an OTA/AO type 41-B and 85 patients an OTA/AO type 41-C tibial plateau fracture. Females had an almost seven times higher risk to suffer a fracture due to low-energy trauma (OR 6.91, 95% CI (3.52, 13.54), p<0.001) than males. In 34% of the patients with affection of the medial tibial plateau, a fracture comminution, primarily due to low-energy trauma (p<0.001), was observed. In type B fractures, the postero-latero-lateral (65.2%), the antero-latero-lateral (64.6%) and the antero-latero-central (60.9%) segment were most frequently affected. Every second type C fracture showed an unique fracture line and zone of comminution. The tibial spine was typically involved (89.4%). A typical fracture pattern of high-energy trauma demonstrated a zone of comminution of the lateral plateau and a split fracture in the medial plateau. The most frequently affected segments were the postero-latero-central (85.9%), postero-central (84.7%), and antero-latero-central (78.8%) segment. CONCLUSION: Posterior segments were the most frequently affected in OTA/AO type B and C fractures. Acknowledging the restricted visibility of posterior segments, whose reduction and fixation is crucial for long-term success, our findings implicate the use of posterior approaches more often in the treatment of tibial plateau fractures. Also, low-energy trauma was identified as an important cause for tibial plateau fractures.