The tipping point in medial opening wedge high tibial osteotomy relates to the shape of the proximal tibia more than to lower limb alignment correction.

PURPOSE: The tipping point (TP) of the knee joint is the centre of rotation of the joint in the coronal plane. This study aimed to define the TP in medial opening wedge high tibial osteotomy (MOWHTO). METHODS: Data from 154 consecutive patients with varus knee malalignment, who underwent MOWHTO between 2017 and 2021, was retrospectively reviewed. The degree of preoperative osteoarthritis (OA), using the Kellgren-Lawrence (KL) grading system, was recorded. Long-leg standing radiographs were used to record the alignment parameters, including the hip-knee-ankle angle (HKA), the mechanical lateral distal femoral angle (mLDFA), the medial proximal tibial angle (MPTA), the joint line convergence angle (JLCA) and the joint line obliquity (JLO) angle. Postoperative Tegner activity scores, Western Ontario and McMaster University Scores and patients' satisfaction were recorded. To define the TP, the relationship of all variables to Δ JLCA (absolute difference between preoperative to postoperative JLCA values) was analysed. Linear regression was employed for Δ JLCA to preoperative JLCA and postoperative and Δ MPTA (absolute difference between preoperative and postoperative values). K-means clustering was used to partition observations into clusters, in which each observation belongs to the cluster with the nearest mean serving as a prototype of the cluster, and analysed if there was any specific threshold influencing Δ JLCA. After defining the TP, further subanalysis of the TP based on the preoperative KL OA grade and analysis of variance of this TP to the KL OA grade was performed. RESULTS: A total of 154 patients (77.9% males and 22.1% females) were included. The mean age was 48.2 ± 11 years, and the mean body mass index was 27.1 ± 4 kg/m2. Preoperatively, 26 (16.9%) patients had KL grade IV OA. The mean preoperative and postoperative JLCA and the significance of their relation to Δ JLCA were 2.6° ± 1.8° (p < 0.0001) and 1.9° ± 1.8° (p = 0.6), respectively. The mean Δ JLCA was 1.4° ± 1.5°. The mean pre- and postoperative MPTA and the significance of their relation to Δ JLCA were 84.6 ± 2.2 (p = 0.005) and 91.8 ± 2.5 (p < 0.0007), respectively. The mean Δ MPTA was 7.2 ± 2.3 (p = 0.3). The mean preoperative and postoperative HKA and the significance of their relation to Δ JLCA were 174.6 ± 2.5 (p = 0.2) and 181.9 ± 2.4 (p = 0.7), respectively. The overall linear regression for Δ JLCA was statistically significant for preoperative JLCA (R2 = 0.3, p < 0.0001) and postoperative MPTA (R2 = 0.09, p = 0.0001) and statistically insignificant for Δ MPTA (R2 = 0.01, p = 0.2) and postoperative HKA (R2 = 0.04, p = 0.7). MPTA > 91.5° was the optimal threshold dividing this series data set between substantial and nonsignificant Δ JLCA. CONCLUSION: In this study, the main predictive factors for intra-articular correction (Δ JLCA) after MOWHTO were the preoperative value of JLCA and the postoperative value of MPTA. A value of 92° for postoperative MPTA is potentially the optimal threshold to predict intra-articular correction. LEVEL OF EVIDENCE: Level IV, retrospective cohort study.

No clinical outcome difference between varus phenotypes after medial opening-wedge high tibial osteotomy at 2 years follow-up.

PURPOSE: Clinical studies regarding medial open-wedge high tibial osteotomy (MOWHTO) often analyse a large group of mechanical varus knees rather than differentiating for its primary varus-inducing component. This study aims to compare the radiological and clinical outcomes of the most prevalent varus malalignment phenotypes using the coronal plane alignment of the knee (CPAK) classification. METHODS: MOWHTO cases with minimal 2-year clinical follow-up were retrospectively selected from a knee osteotomy database (2016-2020). Based on the medial proximal tibial angle (MPTA) and lateral distal femoral angle (LDFA), subjects were allocated to the correct CPAK phenotype pre- and postoperatively. Clinical outcomes were the numeric rating scale (NRS), the knee injury and osteoarthritis outcome score (KOOS) and the therapeutic response rate (TRR) at 2-year follow-up. Inter-observer correlation coefficient (ICC) and unpaired student t test were performed for cross-phenotype comparison. RESULTS: One hundred thirty-five (135) subjects were found eligible (53.0 years old ±9.6 [19-77], 72% male, 53% left-sided). The most prevalent preoperative phenotype was CPAK 1 (n = 70 (52%)) and the postoperative phenotype was CPAK 6 (n = 66 (49%)). All CPAK phenotypes improved significantly relative to baseline but cross-phenotype comparison yielded no significant differences in clinical outcome. The TRR at 2 years was 67% for CPAK 1, 69% for CPAK 2 and 87% for CPAK 4. The TRR for CPAK 6 was 64% compared with 80% for CPAK 9, which was not significantly different. CONCLUSION: At 2-year follow-up, no clinically significant differences are observed between different CPAK phenotypes. Accurate MOWHTO corrections provide significant clinical improvement even in the femoral-driven varus knee and the constitutional varus knee dominated by intra-articular wear. The clinical indication for MOWHTO performance should not be reduced to the medial arthritic varus knee with underlying tibial varus alone. LEVEL OF EVIDENCE: Level IV, retrospective comparative study.

CPAK classification cannot be used to determine segmental coronal extra-articular knee deformity.

PURPOSE: While the coronal plane alignment of the knee (CPAK) classification serves as a useful guide in personalising total knee arthroplasty (TKA), the extent of its correlation with segmental coronal extra-articular knee deformities remains uncertain. This study aims to investigate the potential correlation between CPAK matrix groups and segmental coronal extra-articular deformities in prearthritic knees, shedding light on the relationship between these two factors that seems to be both essential to perform personalised TKA. MATERIALS AND METHODS: A radiological assessment of 1240 nonarthritic knees was performed by evaluating lower limb measurements following the protocol established by Paley et al. Subsequently, all knees were classified into their respective CPAK matrix groups. In our quest to discern any correlation between the CPAK matrix groups and the presence of segmental coronal extra-articular knee deformities, nine potential coronal extra-articular deformity phenotype (CEDP) groupswere identified based on medial proximal tibial angle (MPTA) and mechanical lateral distal femoral angle (mLDFA). Neutral values for MPTA and mLDFA were set at 90.0° ± 3.0° and then at 87.0° ± 2.0°. Each CPAK matrix group underwent detailed coronal morphology analysis and then, segmental coronal extra-articular deformities were assessed by comparing them with the CEDP groups. RESULTS: The study revealed a mean hip-knee-ankle angle (HKA) of 178.6° ± 4.4°, mLDFA of 86.9° ± 2.5°, MPTA of 85.4° ± 2.4°, arithmetic HKA of -1.4° ± 3.2° and joint line obliquity of 172.5° ± 3.7°. The varus CPAK groups (I/IV/VII) included 435 patients, the neutral groups (II/V/VIII) comprised 630 patients and the valgus groups (III/VI/IX) had 175 patients. Notably, CPAK matrix groups were not distinctly associated with specific coronal extra-articular deformity phenotype (CEDP) groups. Particularly among the most common CPAK matrix groups (I/II/III/IV/V), there was a significant variation in segmental coronal extra-articular deformity patterns. Moreover, when neutral MPTA/mLDFA values were set at 87.0° ± 2.0°, the CPAK matrix groups exhibited even greater variability in coronal extra-articular deformities. CONCLUSION: The CPAK matrix groups do not exhibit a direct correlation with a specific extra-articular deformity pattern (CEDP), thus rendering them unsuitable for determining segmental coronal extra-articular knee deformities. LEVEL OF EVIDENCE: Level III, retrospective diagnostic study.

Osteotomy around the painful degenerative varus knee has broader indications than conventionally described but must follow a strict planning process: ESSKA Formal Consensus Part I.

PURPOSE: The European consensus was designed with the objective of combining science and expertise to produce recommendations that would educate and provide guidance in the treatment of the painful degenerative varus knee. Part I focused on indications and planning. METHODS: Ninety-four orthopaedic surgeons from 24 European countries were involved in the consensus, which focused on the most common indications for osteotomy around the knee. The consensus was performed according to an established ESSKA methodology. The questions and recommendations made were initially designed by the consensus steering group. And 'best possible' answers were provided based upon the scientific evidence available and the experience of the experts. The statements produced were further evaluated by ratings and peer review groups before a final consensus was reached. RESULTS: There is no reliable evidence to exclude patients based on age, gender or body weight. An individualised approach is advised; however, cessation of smoking is recommended. The same applies to lesser degrees of patellofemoral and lateral compartment arthritis, which may be accepted in certain situations. Good-quality limb alignment and knee radiographs are a mandatory requirement for planning of osteotomies, and Paley's angles and normal ranges are recommended when undertaking deformity analysis. Emphasis is placed upon the correct level at which correction of varus malalignment is performed, which may involve double-level osteotomy. This includes recognition of the importance of individual bone morphology and the maintenance of a physiologically appropriate joint line orientation. CONCLUSION: The indications of knee osteotomies for painful degenerative varus knees are broad. Part I of the consensus highlights the versatility of the procedure to address multiple scenarios with bespoke planning for each case. Deformity analysis is mandatory for defining the bone morphology, the site of the deformity and planning the correct procedure. LEVEL OF EVIDENCE: Level II, consensus.

Surgical strategy and complication management of osteotomy around the painful degenerative varus knee: ESSKA Formal Consensus Part II.

PURPOSE: The purpose of the European consensus was to provide recommendations for the treatment of patients with a painful degenerative varus knee using a joint preservation approach. Part II focused on surgery, rehabilitation and complications after tibial or femoral correction osteotomy. METHODS: Ninety-four orthopaedic surgeons from 24 countries across Europe were involved in the consensus, which focused on osteotomies around the knee. The consensus was performed according to the European Society for Sports Traumatology, Knee Surgery and Arthroscopy consensus methodology. The steering group designed the questions and prepared the statements based on the experience of the experts and the evidence of the literature. The statements were evaluated by the ratings of the peer-review groups before a final consensus was released. RESULTS: The ideal hinge position for medial opening wedge high tibial osteotomy (MOW HTO) should be at the upper level of the proximal tibiofibular joint, and for lateral closing wedge distal femoral osteotomy (LCW DFO) just above the medial femoral condyle. Hinge protection is not mandatory. Biplanar osteotomy cuts provide more stability and quicker bony union for both MOW HTO and LCW DFO and are especially recommended for the latter. Osteotomy gap filling is not mandatory, unless structural augmentation for stability is required. Patient-specific instrumentation should be reserved for complex cases by experienced hands. Early full weight-bearing can be adopted after osteotomy, regardless of the technique. However, extra caution should be exercised in DFO patients. Osteotomy patients should return to sports within 6 months. CONCLUSION: Clear recommendations for surgical strategy, rehabilitation and complications of knee osteotomies for the painful degenerative varus knee were demonstrated. In Part 2 of the consensus, high levels of agreement were reached by experts throughout Europe, under variable working conditions. Where science is limited, the collated expertise of the collaborators aimed at providing guidance for orthopaedic surgeons developing an interest in the field and highlighting areas for potential future research. LEVEL OF EVIDENCE: Level II, consensus.

Fatigue-induced Landing Alterations in ACL Reconstructed Athletes after Return-to-Sport.

At the time of return-to-sport, anterior cruciate ligament reconstructed athletes still show altered neuromechanics in their injured leg during single leg hopping tasks. Part of these alterations can be magnified when these athletes are fatigued. So far, little is known whether fatigue-induced landing alterations persist after return-to-sport. Therefore, the aim of this study was to evaluate whether these alterations persist in the six months following return-to-sport. Sixteen anterior cruciate ligament reconstructed athletes performed five unilateral hop tasks before and after a fatigue protocol. The hop tasks were executed at three different time points (return-to-sport, 3 and 6 months post-return-to-sport). A 2-by-3 repeated measures ANOVA was performed to evaluate whether fatigue-induced landing alterations persisted 3 and 6 months following return-to-sport. At 6 months following return-to-sport, fatigue still induces a reduction in hamstring medialis activation and an increase in the knee abduction moment during a vertical hop with 90-degree inward rotation. Most fatigue-induced landing alterations present at the time of return-to-sport normalize after resumption of sports activities. However, a larger knee abduction moment in the injured leg after resumption of sports activities can still be observed.

The position of the lateral tibial spine and the implications for high tibial osteotomy planning.

The lateral tibial spine (LTS) is frequently proposed as a correction target in high tibial osteotomy (HTO), although little is known about its exact radiographic position. This study primarily aims to define the position and variance of the LTS. Secondly, this study wants to investigate the relevance of the LTS position on the mechanical tibiofemoral angle (mTFA°) while planning and postoperatively landing the weight-bearing line (WBL) on this landmark. The LTS position was studied on preoperative full-leg standing radiographs (FLSR) and computed tomography (CT) scans in 70 cases. 3D models of the tibia were created in Mimics 23.0 and measurements were conducted in 3-matic 15.0 (Materialise, Leuven®). Next, 100 HTO cases were retrospectively planned with the WBL through the LTS according to Dugdale's method on FLSR. Finally, 55 postoperative FLSR which had the WBL on the LTS (±2%) were assessed for mTFA° outcome. Statistics were conducted in GraphPad 8.0. The LTS was located at 58.3%±1.9 [55-63%] in 2D and 57.3%±2.2 [53-63%] in 3D showing a high correlation (r=0.77 [0.65 to 0.85]). The planned mTFA on the LTS was 181.8°±0.3 (181.3°-182.5°). On postoperative FLSR, the mTFA was 182.2°±0.6 (180.9°-183.1°). The lateral tibial spine is located at 57-58% on the tibial plateau with a 10% maximal variation range. Good agreement was found between 2D and 3D imaging modalities while evaluating its position in the coronal plane. When aiming the WBL through the LTS during valgus-producing HTO, a consistent realignment of 181-183° mTFA can be expected when performing accurate surgery.

IC-Type Electric stimulation for delayed bone healing: monocentric evaluation over eight years of experience.

Electrostimulation is suggested to positively influence bone healing for delayed unions of both fractures and osteotomies. This monocentric series aims to retrospectively assess the outcome of electrostimulation treatment for delayed union after traumatic fractures or knee osteotomy. Patients treated with electrostimulation for delayed union (no bony union on radiographic imaging at 90 days after osteotomy or fracture treatment) over an 8-year period were screened. The delay of treatment, success rate, revision rate and demographic data (age, sex, location of fracture, presence of osteosynthesis materials) were investigated. A questionnaire assessed objective (nicotine abuse, NRS pain assessment, activity levels) and subjective (comfort, usability, cost-effectiveness) aspects. Electrostimulation delivered radiographic healing in 75% of the fracture group and 66% of the osteotomy group. No statistical significant difference (N=136) in success rate was found for age, sex, presence of osteosynthesis material, delay or fracture location. Success rate did differ significantly with pain, activity level and smoking (p<0.05). Reflective questions to patients were answered mostly positively. The use of electrostimulation for the delayed union of fractures and knee osteotomies delivers high healing rates avoiding the burden of surgical reintervention. It is generally well received by the patient. No difference in success rate was found between sex, age or fracture location, nor did the delay of therapy onset or presence of osteosynthesis material seem to affect the success rate. Smoking had a negative influence on the efficacy of bone electrostimulation.

Magnetic Resonance Imaging Evaluation of the Anterolateral Ligament and the Iliotibial Band in Acute Anterior Cruciate Ligament Injuries Associated With Segond Fractures.

PURPOSE: To evaluate the magnetic resonance imaging (MRI) characteristics of Segond fractures, including the structures attached to the avulsed fragment, the integrity of anterolateral ligament (ALL) and iliotibial band (ITB), and fragment size and location. METHODS: This was a retrospective, cross-sectional study with MRI scans from 2016 to 2019 with the term "Segond" in the reports, signs of acute trauma, and a bony anterolateral tibial avulsion (Segond) fracture. Two experienced observers accessed images to evaluate fragment dimensions (anteroposterior, mediolateral, and craniocaudal) and distances from anatomic landmarks (Gerdy's tubercle, articular surface, and posterolateral tibial corner). ALLs and ITBs also were evaluated, both for integrity and for attachment to the avulsed bony fragment. Data were statistically evaluated for significant correlations. RESULTS: Forty-eight knee MRIs of patients suffering from a combined anterior cruciate ligament and Segond injury were evaluated. The ALL presented with edema in 28 cases (58.3%) and was torn in 3 cases (6.3%). The ALL was attached to the bone fragment in all cases and the ITB also was attached in 25 cases (52.1%). Receiver operating characteristic curves also demonstrated that the larger each of the dimensions and the volume of the fragment, the greater the probability of ITB fibers being inserted. Also, the narrower the distance from the fragment to the center of Gerdy's tubercle, the greater the probability of iliotibial band fibers being attached. Interobserver correlation varied from 0.87 to 0.97 for all measurements. CONCLUSIONS: In all combined ACL injuries and Segond fracture MRI cases, the complete ALL inserted on the avulsed bony fragment, whereas the posterior part of the ITB was only attached in 52.1% of the cases. Segond fracture fragment size was predictive for the structures attached to it. The ALL was abnormal in 64.5% of cases and presented a clear discontinuity in 6.3%. LEVEL OF EVIDENCE: Case Series, Level IV.

Structural allograft impaction enables fast rehabilitation in opening-wedge high tibial osteotomy: a consecutive case series with one year follow-up.

PURPOSE: Painful and slow recovery are the presumed disadvantages after opening-wedge high tibial osteotomy (HTO) and play a role in favouring arthroplasty as treatment for moderate isolated medial knee arthritis. The primary study objective was to investigate the effect of press-fit structural impacted bone allograft with locking plate fixation on early ambulation, postoperative pain levels, and resumption of daily-life activities in opening-wedge HTO. METHODS: A prospective consecutive opening-wedge HTO case series was conducted, including 103 patients with final follow-up at 1 year. Weight-bearing was allowed from the day after surgery "as tolerated" by the patient. Clinical assessment included the Numeric Rating Scale (NRS), Knee injury and Osteoarthritis Outcome Score (KOOS), and Lysholm score. Additionally, the Knee Society Score (KSS) was assessed during consultation at 1, 3, and 12 months postoperatively with special attention for clinical anchor questions. Required sample size was calculated and a linear mixed-effect model was used for repeated measures over time of the clinical scores. RESULTS: The NRS decreased by 1.5 at 1 month (p < 0.01) and 2.1 at 3 months (p < 0.01), while KOOS pain significantly improved with 19.2 (p < 0.01) by this time compared to baseline. Under reduced pain levels, 98% were able to walk > 500 m without support, while all patients were able to climb up and down the stairs 3 months postoperatively. CONCLUSION: The study strongly supports the initial hypothesis that applying structural triangular bone allograft in HTO leads to low postoperative pain levels, early ambulation, and excellent short-term clinical outcomes. Study results have the potential to alter the general perception about HTO being a painful procedure with painstakingly slow recovery and consequently encourage the consideration of HTO as a highly valuable joint-preserving option, while treating unicompartmental knee arthritis. LEVEL OF EVIDENCE: IV (case series).

Etiology of knee pain in elite cyclists: A 14-month consecutive case series.

Overuse injuries of the knee are a common cause of missed training and competition days in elite cyclists, however the underlying conditions causing this knee pain are not well defined. We conducted a diagnostic study, investigating a consecutive series of 53 high level cyclists with non-traumatic knee pain over a 14 month period. Demographic data on the participants' cycling specialty and training level was noted. Clinical information concerning knee pain intensity, location and occurrence were collected using a questionnaire. Our results show 7 different overuse injuries were identified. The prepatellar friction syndrome accounted for the majority of these overuse injuries (46%), while medial plica syndrome (15%), biceps femoris tendinopathy (7.5%), patellar tendinopathy (9.4%), infrapatellar plica friction syndrome (7.5%), infrapatellar fat pad impingement (5.7%) and iliotibial band syndrome (3.7%) were other causes of knee pain in these athletes. In contrast to current belief, our results show that instead of patellofemoral cartilage overload, friction related overuse injuries are the most frequent and underestimated cause of knee pain in high level cyclists.

The anterolateral complex of the knee: results from the International ALC Consensus Group Meeting.

The structure and function of the anterolateral complex (ALC) of the knee has created much controversy since the 're-discovery' of the anterolateral ligament (ALL) and its proposed role in aiding control of anterolateral rotatory laxity in the anterior cruciate ligament (ACL) injured knee. A group of surgeons and researchers prominent in the field gathered to produce consensus as to the anatomy and biomechanical properties of the ALC. The evidence for and against utilisation of ALC reconstruction was also discussed, generating a number of consensus statements by following a modified Delphi process. Key points include that the ALC consists of the superficial and deep aspects of the iliotibial tract with its Kaplan fibre attachments on the distal femur, along with the ALL, a capsular structure within the anterolateral capsule. A number of structures attach to the area of the Segond fracture including the capsule-osseous layer of the iliotibial band, the ALL and the anterior arm of the short head of biceps, and hence it is not clear which is responsible for this lesion. The ALC functions to provide anterolateral rotatory stability as a secondary stabiliser to the ACL. Whilst biomechanical studies have shown that these structures play an important role in controlling stability at the time of ACL reconstruction, the optimal surgical procedure has not yet been defined clinically. Concern remains that these procedures may cause constraint of motion, yet no clinical studies have demonstrated an increased risk of osteoarthritis development. Furthermore, clinical evidence is currently lacking to support clear indications for lateral extra-articular procedures as an augmentation to ACL reconstruction. The resulting statements and scientific rationale aim to inform readers on the most current thinking and identify areas of needed basic science and clinical research to help improve patient outcomes following ACL injury and subsequent reconstruction.Level of evidence V.

The Anterolateral Ligament Has Similar Biomechanical and Histologic Properties to the Inferior Glenohumeral Ligament.

PURPOSE: To characterize the tensile and histologic properties of the anterolateral ligament (ALL), inferior glenohumeral ligament (IGHL), and knee capsule. METHODS: Standardized samples of the ALL (n = 19), anterolateral knee capsule (n = 15), and IGHL (n = 13) were isolated from fresh-frozen human cadavers for uniaxial tensile testing to failure. An additional 6 samples of the ALL, capsule, and IGHL were procured for histologic analysis and determination of elastin content. RESULTS: All investigated mechanical properties were significantly greater for both the ALL and IGHL when compared with capsular tissue. In contrast, no significant differences between the ALL and IGHL were found for any property. The elastic modulus of ALL and IGHL samples was 174 ± 92 MPa and 139 ± 60 MPa, respectively, compared with 62 ± 30 MPa for the capsule (P = .001). Ultimate stress was significantly lower (P < .001) for the capsule, at 13.4 ± 7.7 MPa, relative to the ALL and IGHL, at 46.4 ± 20.1 MPa and 38.7 ± 16.3 MPa, respectively. The ultimate strain at failure was 37.8% ± 7.9% for the ALL and 39.5% ± 9.4% for the IGHL; this was significantly greater (P = .041 and P = .02, respectively) for both relative to the capsule, at 32.6% ± 8.4%. The strain energy density was 7.8 ± 3.1 MPa for the ALL, 2.1 ± 1.3 MPa for the capsule, and 7.1 ± 3.1 MPa for the IGHL (P < .001). The ALL and IGHL consisted of collagen bundles aligned in a parallel manner, containing elastin bundles, which was in contrast to the random collagen architecture noted in capsule samples. CONCLUSIONS: The ALL has similar tensile and histologic properties to the IGHL. The tensile properties of the ALL are significantly greater than those observed in the knee capsule. CLINICAL RELEVANCE: The ALL is not just a thickening of capsular tissue and should be considered a distinct ligamentous structure comparable to the IGHL in the shoulder. The tensile behavior of the ALL is similar to the IGHL, and treatment strategies should take this into account.

International Perspective on Revision Anterior Cruciate Ligament Reconstruction: What Have We Been Missing?

Primary anterior cruciate ligament (ACL) reconstruction is a common orthopaedic procedure. A graft failure rate of 5% to 10% after primary ACL reconstruction has resulted in an increased need for revision ACL reconstruction. ACL reconstruction failure etiologies include trauma, technical errors, and biologic factors. Based on the current literature, the outcomes of revision ACL reconstruction are clearly inferior compared with those of primary reconstruction. A thorough patient evaluation, including surgical history, a physical examination, and imaging studies, is crucial in the assessment of a failed ACL reconstruction. Tunnel malposition, which is a technical error, is the most common reason for ACL reconstruction failure. Tunnel positioning and widening are important factors to consider in the decision to perform either one-stage or two-stage revision ACL reconstruction. Other concomitant factors such as malalignment, pathologic posterior tibial slope, and meniscal or ligamentous deficiency (in particular, deficiency of the anterolateral ligament) must be considered and addressed to achieve an optimal outcome. Patients who have a positive pivot shift test and rotational instability may require extra-articular anterolateral ligament reconstruction. In addition, patients who have severe pathologic tibial slope and anterior tibial translation may require a tibial deflexion osteotomy.

Contributions of the anterolateral complex and the anterolateral ligament to rotatory knee stability in the setting of ACL Injury: a roundtable discussion.

Persistent rotatory knee laxity is increasingly recognized as a common finding after anterior cruciate ligament (ACL) reconstruction. While the reasons behind rotator knee laxity are multifactorial, the impact of the anterolateral knee structures is significant. As such, substantial focus has been directed toward better understanding these structures, including their anatomy, biomechanics, in vivo function, injury patterns, and the ideal procedures with which to address any rotatory knee laxity that results from damage to these structures. However, the complexity of lateral knee anatomy, varying dissection techniques, differing specimen preparation methods, inconsistent sectioning techniques in biomechanical studies, and confusing terminology have led to discrepancies in published studies on the topic. Furthermore, anatomical and functional descriptions have varied widely. As such, we have assembled a panel of expert surgeons and scientists to discuss the roles of the anterolateral structures in rotatory knee laxity, the healing potential of these structures, the most appropriate procedures to address rotatory knee laxity, and the indications for these procedures. In this round table discussion, KSSTA Editor-in-Chief Professor Jón Karlsson poses a variety of relevant and timely questions, and experts from around the world provide answers based on their personal experiences, scientific study, and interpretations of the literature. Level of evidence V.

Anterolateral Ligament Expert Group consensus paper on the management of internal rotation and instability of the anterior cruciate ligament - deficient knee.

Purpose of this paper is to provide an overview of the latest research on the anterolateral ligament (ALL) and present the consensus of the ALL Expert Group on the anatomy, radiographic landmarks, biomechanics, clinical and radiographic diagnosis, lesion classification, surgical technique and clinical outcomes. A consensus on controversial subjects surrounding the ALL and anterolateral knee instability has been established based on the opinion of experts, the latest publications on the subject and an exchange of experiences during the ALL Experts Meeting (November 2015, Lyon, France). The ALL is found deep to the iliotibial band. The femoral origin is just posterior and proximal to the lateral epicondyle; the tibial attachment is 21.6 mm posterior to Gerdy's tubercle and 4-10 mm below the tibial joint line. On a lateral radiographic view the femoral origin is located in the postero-inferior quadrant and the tibial attachment is close to the centre of the proximal tibial plateau. Favourable isometry of an ALL reconstruction is seen when the femoral position is proximal and posterior to the lateral epicondyle, with the ALL being tight upon extension and lax upon flexion. The ALL can be visualised on ultrasound, or on T2-weighted coronal MRI scans with proton density fat-suppressed evaluation. The ALL injury is associated with a Segond fracture, and often occurs in conjunction with acute anterior cruciate ligament (ACL) injury. Recognition and repair of the ALL lesions should be considered to improve the control of rotational stability provided by ACL reconstruction. For high-risk patients, a combined ACL and ALL reconstruction improves rotational control and reduces the rate of re-rupture, without increased postoperative complication rates compared to ACL-only reconstruction. In conclusion this paper provides a contemporary consensus on all studied features of the ALL. The findings warrant future research in order to further test these early observations, with the ultimate goal of improving the long-term outcomes of ACL-injured patients. Level of evidence Level V-Expert opinion.

Prepatellar Friction Syndrome: a common cause of knee pain in the elite cyclist.

BACKGROUND: Although anterior knee pain is extremely common in high-level road cyclists, the exact etiology still remains unclear. METHODS: A group of 28 professional male elite cyclists diagnosed with Prepatellar Friction Syndrome (PPFS) were retrospectively reviewed with specific attention for the typical history, clinical findings and treatment modalities. RESULTS: A traumatic onset of the complaints was reported by 10 athletes, while the complaints were caused by chronic overuse in the remaining 18 subjects. Conservative treatment delivered poor results and all cases were eventually treated surgically. Surgery confirmed macroscopic damage to at least one prepatellar fascial layer in all patients, after which partial fasciectomy was performed through a mini incision. CONCLUSION: PPFS is a new clinical entity of the triple-layered prepatellar fascial structures. Correct diagnosis is critical and based on the typical history and clinical findings. Partial prepatellar fasciectomy is the treatment of choice in order to regain the pre-injury performance level.

A novel core biopsy technique for anterior cruciate ligament preserves ligament structural integrity: a porcine study.

PURPOSE: The objective of this study was to validate a new technique to safely obtain core biopsy specimens of the anterior cruciate ligament (ACL) without jeopardizing the ACL's biomechanical properties. METHODS: Eleven pairs of fresh porcine femur-ACL-tibia complexes were tested in a loading frame. The ACL of one knee was biopsied using a spring-loaded core biopsy device, whereas the contralateral ACL was tested as the control. Biomechanical properties of the biopsied and control ACLs were compared. RESULTS: The ultimate load to failure was 1,202 N ± 171.1 N and 1,193 N ± 228.7 N (P = .8984) for biopsied and non-biopsied ACLs, respectively. No significant differences were noted for maximal elongation at failure, maximal strain, absorbed energy, and stiffness between biopsied and non-biopsied ACLs. CONCLUSIONS: The results of this study indicate that a new ACL core biopsy technique can be performed while preserving the ligament's structural integrity. CLINICAL RELEVANCE: The presented core biopsy technique could be regarded as a dedicated tool to elucidate the poorly understood (patho)biological processes occurring in both the native and reconstructed ACLs.

The Segond fracture: a bony injury of the anterolateral ligament of the knee.

PURPOSE: The purpose of this study was to investigate the relation of the Segond fracture with the anterolateral ligament (ALL) of the knee. METHODS: To identify the soft-tissue structure causative for the Segond fracture, a study was set up to compare anatomic details of the tibial insertion of the recently characterized ALL in cadaveric knees (n = 30) with radiologic data obtained from patients (n = 29) with a possible Segond fracture based on an imaging protocol search. The spatial relation of the ALL footprint with well-identifiable anatomic landmarks at the lateral aspect of the knee was determined, and this was repeated for the Segond fracture bed. RESULTS: In all of the included cadaveric knees, a well-defined ALL was found as a distinct ligamentous structure connecting the lateral femoral epicondyle with the anterolateral proximal tibia. The mean distance of the center of the tibial ALL footprint to the center of the Gerdy tubercle (GT-ALL distance) measured 22.0 ± 4.0 mm. The imaging database search identified 26 patients diagnosed with a Segond fracture. The mean GT-Segond distance measured 22.4 ± 2.6 mm. The observed difference of 0.4 mm (95% confidence interval, -1.5 to 2.2 mm) between the GT-ALL distance and GT-Segond distance was neither statistically significant (P = .70) nor clinically relevant. CONCLUSIONS: The results of this study confirmed the hypothesis that the ALL inserts in the region on the proximal tibia from where Segond fractures consistently avulse, thus suggesting that the Segond fracture is actually a bony avulsion of the ALL. CLINICAL RELEVANCE: Although the Segond fracture remains a useful radiographic clue for indirect detection of anterior cruciate ligament injuries, the Segond fracture should be considered a frank ligamentous avulsion itself.

High prevalence of anterolateral ligament abnormalities in magnetic resonance images of anterior cruciate ligament-injured knees.

The purpose of this study was to identify the newly described anterolateral ligament of the human knee on magnetic resonance imaging and to describe its eventual radiological abnormalities in anterior cruciate ligament-injured subjects. A retrospective cohort study on a series of consecutive subjects undergoing anterior cruciate ligament reconstructive surgery was performed. The MR images of 206 included knees were studied and the status of the anterolateral ligament status was judged to be either "non-visualized", "normal" or "abnormal". Of all the visualized anterolateral ligaments, 44 (21.3%) were considered uninjured, while 162 (78.8%) knees demonstrated radiological ALL abnormalities. The majority of ALL abnormalities were situated in the distal part of the ligament (77.8%). In conclusion, the anterolateral ligament can be identified on classic knee magnetic resonance images. Although anterior cruciate ligament injured subjects often demonstrated associated anterolateral ligament lesions, further research is needed in order to establish the clinical relevance of these highly frequent radiological abnormalities.