The Fibular Collateral Ligament is a More Important Restraint to Varus Laxity Compared to the Anterolateral Complex in the Anterior Cruciate Ligament Deficient Knee in a Cadaveric Biomechanical Study.

PURPOSE: The purpose of this study was to compare the influence of the fibular collateral ligament (FCL) and the anterolateral complex (ALC) on varus knee laxity in paired anterior cruciate ligament (ACL)-deficient cadaveric knees using varus stress radiographs. METHODS: Varus laxity in nine paired (N=18, mean age 73.8 years) human cadaveric knees was assessed using varus stress radiographs with a 12 Nm varus stress applied at 20° of knee flexion. All knees underwent testing in the intact state and following ACL sectioning. One knee of each pair was randomly assigned to undergo FCL sectioning and the contralateral knee was assigned to undergo ALC sectioning (anterolateral ligament [ALL] followed by the Kaplan fibers). RESULTS: Both FCL sectioning and ALC (ALL and the Kaplan fibers) sectioning resulted in increased lateral compartment gapping compared to the intact state, 2.44 mm and 1.13 mm, respectively. ALL sectioning with intact Kaplan fibers did not result in increased lateral compartment gapping. Paired knee comparison revealed a significantly greater influence of the FCL than the ALC in restraining lateral compartment gapping under an applied varus stress (p=0.0003). CONCLUSIONS: Sectioning the FCL resulted in significantly greater lateral compartment gapping under a varus stress than combined sectioning of the ALL and Kaplan fibers in an ACL deficient knee, although both scenarios resulted in significantly increased gapping compared to the intact state. Sectioning of the ALL with intact Kaplan fibers did not result in increased lateral compartment gapping. CLINICAL RELEVANCE: The FCL is the most important structure in restraining varus laxity in the ACL deficient knee and the ALC is of secondary importance in restraining varus laxity. In ACL deficient patients with a high-grade pivot shift, mild varus laxity on clinical examination, and an intact FCL on MRI, injury to the anterolateral complex should be considered and may be evaluated with varus stress radiographs. This study validates prior biomechanical studies of FCL deficiency and demonstrates that approximately 1 mm increase in lateral compartment gapping on varus stress radiographs may occur secondary to ALC injury and clinicians should be aware of this when considering treatment for ACL deficient patients with high-grade anterolateral laxity.

Multiligament knee injury (MLKI): an expert consensus statement on nomenclature, diagnosis, treatment and rehabilitation.

Multiligament knee injuries (MLKIs) represent a broad spectrum of pathology with potentially devastating consequences. Currently, disagreement in the terminology, diagnosis and treatment of these injuries limits clinical care and research. This study aimed to develop consensus on the nomenclature, diagnosis, treatment and rehabilitation strategies for patients with MLKI, while identifying important research priorities for further study. An international consensus process was conducted using validated Delphi methodology in line with British Journal of Sports Medicine guidelines. A multidisciplinary panel of 39 members from 14 countries, completed 3 rounds of online surveys exploring aspects of nomenclature, diagnosis, treatment, rehabilitation and future research priorities. Levels of agreement (LoA) with each statement were rated anonymously on a 5-point Likert scale, with experts encouraged to suggest modifications or additional statements. LoA for consensus in the final round were defined 'a priori' if >75% of respondents agreed and fewer than 10% disagreed, and dissenting viewpoints were recorded and discussed. After three Delphi rounds, 50 items (92.6%) reached consensus. Key statements that reached consensus within nomenclature included a clear definition for MLKI (LoA 97.4%) and the need for an updated MLKI classification system that classifies injury mechanism, extent of non-ligamentous structures injured and the presence or absence of dislocation. Within diagnosis, consensus was reached that there should be a low threshold for assessment with CT angiography for MLKI within a high-energy context and for certain injury patterns including bicruciate and PLC injuries (LoA 89.7%). The value of stress radiography or intraoperative fluoroscopy also reached consensus (LoA 89.7%). Within treatment, it was generally agreed that existing literature generally favours operative management of MLKI, particularly for young patients (LoA 100%), and that single-stage surgery should be performed whenever possible (LoA 92.3%). This consensus statement will facilitate clinical communication in MLKI, the care of these patients and future research within MLKI.

Knee Posterolateral Corner Reconstruction Shows Low Failure and Complication Rates.

High-grade knee posterolateral corner (PLC) injuries are potentially devastating, and often associated with high energy mechanisms. Failure of PLC injury diagnosis or treatment can lead to residual instability after combined cruciate ligament reconstruction due to increased risk of graft failure, and varus malalignment may lead to early osteoarthritis and meniscal injuries. PLC reconstruction has consistently shown superiority over PLC repair. Biomechanical studies have compared reconstruction techniques, specifically evaluating rotational and varus laxity. Some studies have demonstrated no difference between techniques whereas other studies have reported improved stability with techniques that include a separate tibial tunnel for reconstruction of the popliteus tendon and PFL. Yet many have suggested that there is less technical difficulty with techniques that do not use a tibial tunnel, and this may be an important consideration in certain settings. Recent reviews showing no differences in clinical outcomes when comparing techniques for PLC reconstruction are based on heterogeneous, low level of evidence, high-risk-of-bias literature. It is well-recognized that PLC injuries are heterogeneous, with approximately three quarters occurring in combination with anterior and/or posterior cruciate ligament tears. Further, laxity patterns vary for these injuries including high-grade posterior laxity and knee hyperextension as well as proximal tibial-fibular joint laxity, and these findings may necessitate use of an anatomic (separate tibial tunnel) PLC reconstruction technique. Reassuringly, both techniques show low complication and failure rates.comparison.

Postoperative healing and complications based on anterior cruciate ligament reconstruction graft type.

Injury to the anterior cruciate ligament (ACL) is a devastating injury to athletes of all ages. The current gold standard treatment following complete rupture of the ACL is reconstruction of the torn ligament with autograft or allograft tendon. Commonly used tendon grafts include patellar tendon, hamstring tendon, and quadriceps tendon. Although ligaments and tendons have similar collagen and proteoglycan compositions, they maintain a unique composition and arrangement of cells to serve their unique biomechanical needs. Therefore, following ACL reconstruction (ACLR), the implanted tendon tissue undergoes a process of remodeling which is termed "ligamentization". The process of ligamentization is divided into three main phases, which include the early healing phase, the proliferative phase, and the maturation phase. Following the process of ligamentization, the graft tissue closely mimics the appearance of ligament tissue on an ultrastructural level. Successful outcome following ACLR is contingent upon adequate remodeling of the tissue as well as healing of the graft within the bone tunnels in the femur and tibia. Choice of graft has individual implications regarding their associated risk of complications, failure, and infection. The purpose of this review is to summarize the process of ligamentization and graft healing and to discuss how graft type influences the rate and types of complications, failures, and infections.

Editorial Commentary: Medial Meniscal Ramp Lesions in the Setting of Anterior Cruciate Ligament Tears Contribute to High-Grade Anterior and Rotatory Laxity That Are Normalized by Repair.

Meniscal ramp lesions are reported to occur in 9% to 42% of anterior cruciate ligament tears. Biomechanical research shows that the presence of a meniscal ramp lesion, in the setting of an anterior cruciate ligament tear, leads to increased knee anteroposterior and rotatory laxity when compared with an uninjured medial meniscus. This finding also has been verified clinically. Repair of ramp lesions has been shown to improve biomechanics. Accordingly, the influence of meniscal ramp lesions on knee laxity necessitates a comprehensive physical examination, imaging review, and diagnostic arthroscopy to support identification and treatment of these injuries. Arthroscopic probing is required to assess ramp lesion stability. It is generally accepted that up to 30% of ramp lesions are unstable and warrant repair, as determined by tear ≤1 cm, displacement into the medial compartment with probing, and extension beyond the lower pole of the femoral condyle.

Functional anterior cruciate ligament braces may have a role in select patient groups although there is presently limited evidence supporting or refuting their routine use: A scoping review of clinical practice guidelines and an updated bracing classification.

PURPOSE: The purpose of this study was to perform a scoping review of clinical practice guidelines (CPGs) concerning the use of functional anterior cruciate ligament (ACL) braces and to clarify the nomenclature for bracing relevant to ACL injury treatment in order to support prescribing clinicians. METHODS: A PubMed search for CPGs for the use of braces following ACL injury or reconstruction was performed. CPGs on the treatment of ACL injuries with sufficient attention to postoperative braces were included in this scoping review. The references used for supporting the specific CPG recommendations were reviewed. Specific indications for brace use including brace type, period of use following surgery and activities requiring brace use were collected. RESULTS: Six CPGs were identified and included this this review. Three randomised trials provided the evidence for recommendations on functional brace use following ACL reconstruction in the six CPGs. Functional ACL braces were the primary focus of the three randomised trials, although extension braces (postoperative knee immobilisers) were also discussed. A novel dynamic ACL brace category has been described, although included CPGs did not provide guidance on this brace type. CONCLUSIONS: Guidance on the use of functional ACL braces following ACL reconstruction is provided in six CPGs supported by three randomised trials. However, the brace protocols and patient compliance in the randomised trials render these CPGs inadequate for providing guidance on the use of functional ACL braces in the general and high-risk patient populations when returning to sport after ACL reconstruction. Functional ACL braces are commonly utilised during the course of ACL injury treatment although there is presently limited evidence supporting or refuting the routine use of these braces. Future studies are, therefore, necessary in order to provide guidance on the use of functional and dynamic ACL braces in high-risk patient populations. LEVEL OF EVIDENCE: Level II.

Differences Between Traumatic and Degenerative Medial Meniscus Posterior Root Tears: A Systematic Review.

BACKGROUND: Intact meniscus roots are a prerequisite for normal meniscal function, including even distribution of compressive forces across the knee joint. An injury to the root disrupts the hoop strength of the meniscus and may lead to its extrusion and the development of osteoarthritis. A medial meniscus posterior root tear (MMPRT) is often thought to have a primary degenerative pathogenesis. However, there is mention of some cases of MMPRTs where the patients have a solely traumatic injury to a previously healthy meniscus. PURPOSE: To describe a subpopulation of patients with traumatic MMPRT. STUDY DESIGN: Systematic review; Level of evidence, 5. METHODS: The Web of Science database (www.webofscience.com) was queried using the Medical Subject Headings term "medial root tear." Articles were reviewed, and those evaluated for MMPRTs in a degenerative meniscus were excluded. A total of 25 articles describing cases of acute traumatic causes were included in this study. For these articles, the patient characteristics, injury mechanisms, and concomitant injuries evaluated were recorded and pooled. RESULTS: The search revealed 660 articles, and 25 were selected for inclusion. A total of 113 patients with a traumatic MMPRT were identified and included in this review. The study population had a mean age of 27.1 years and a high share of men (64%). Also, this review displays how most patients with traumatic MMPRTs also suffer concomitant injuries (68%). CONCLUSION: The findings in this review support our hypothesis that there is a unique subgroup with acute traumatic MMPRTs that have unique patient characteristics, injury mechanisms, and combined injuries, compared with previously published reviews on MMPRTs.

Radiographic and Dynamic Assessment for Resection of Cam Lesions in Patients With Femoroacetabular Impingement.

Cam-type femoroacetabular impingement is characterized by a pathologic asphericity of the femoral head-neck junction, and arthroscopic femoral osteoplasty is indicated to correct the bony abnormality and restore normal hip mechanics when symptomatic. Residual femoroacetabular impingement deformity after arthroscopy is a leading cause of failure, and it is therefore critical to perform a thorough fluoroscopic and dynamic assessment when addressing cam deformities arthroscopically. The fluoroscopic assessment uses 6 anteroposterior views, including 3 in hip extension (30° internal rotation, neutral rotation, and 30° external rotation) and 3 in 50° flexion (neutral rotation, 40° external rotation, 60° of external rotation), performed before, during, and after the femoral resection. The dynamic assessment includes evaluation of impingement-free range of motion and "end feel" (a subjective description of the tactile feedback during assessment of hip motion), and should be performed before and after the femoral resection in 3 specific positions (extension/abduction, flexion/abduction, and flexion/internal rotation). Although the anterior aspect of the head-neck junction is readily accessed through standard arthroscopic portals with the hip in 30 to 50° of flexion, the posterolateral, posteromedial, and posterior extent of the femoral head-neck junction are challenging to address. The natural external rotation of the proximal femur during flexion and internal rotation during extension can be used to gain posterior lateral and medial access. Antero/posteromedial femoral access can be obtained with >50° of hip flexion with the burr in the anteromedial portal. Posterolateral femoral access is achieved with hip extension with the burr in the anterolateral portal, and further posterolateral access can be achieved with the addition of traction, allowing resection of posterolateral deformities extending beyond the lateral retinacular vessels while remaining proximal to the vessels. This comprehensive intraoperative fluoroscopic and dynamic assessment and surgical technique can lead to a predictable correction of most cam-type deformities.

Diagnosis and treatment strategies of the multiligament injured knee: a scoping review.

OBJECTIVE: To map the current literature evaluating the diagnosis and treatment of multiligament knee injuries (MLKIs). DESIGN: Scoping review. DATA SOURCES: Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews and Arksey and O'Malley frameworks were followed. A three-step search strategy identified relevant published literature comprising studies reporting on at least one aspect in the diagnosis or treatment of MLKI in adults. Data were synthesised to form a descriptive analysis and thematic summary. RESULTS: Overall, 417 studies were included. There was a substantial chronological increase in the number of studies published per year, with 70% published in the last 12 years. Of included studies, 128 (31%) were narrative reviews, editorials or technical notes with no original data. The majority of studies (n=239, 57%) originated from the USA; only 4 studies (1%) were of level I evidence. Consistent themes of contention included clinical assessment, imaging, operative strategy, timing of surgery and rehabilitation. There was a lack of gender and ethnic diversity reported within patient groups. CONCLUSIONS: There remains insufficient high-level evidence to support definitive management strategies for MLKI. There is considerable heterogeneity in outcome reporting in current MLKI literature, precluding robust comparison, interpretation and pooling of data. Further research priorities include the development of expert consensus relating to the investigation, surgical management and rehabilitation of MLKI. There is a need for minimum reporting standards for clinical studies evaluating MLKI.

Repair of Quadriceps and Patellar Tendon Tears.

Tears of the quadriceps or patellar tendon usually occur after a sudden eabccentric contraction and are diagnosed by a palpable gap at the injury site combined with an inability to perform a straight leg raise. Bilateral knee radiographs may demonstrate patella alta with patellar tendon tears and patella baja with quadriceps tendon tears compared with the uninjured knee. Ultrasound and magnetic resonance imaging can be helpful when there is uncertainty in the diagnosis. Surgical treatment is indicated for complete tears and some high-grade, partial tears. Nonabsorbable high-strength sutures or suture tape are placed in running locking fashion along the injured tendon and secured to the patella with bone tunnels (i.e., transosseous) or suture anchors. The transosseous technique requires exposure of the length of the patella to drill 3 bone tunnels to shuttle the sutures and tie over either pole of the patella. The suture anchor technique allows for a smaller incision and less soft-tissue dissection and may use a knotted or knotless technique. Biomechanical testing with load to failure is not statistically different between the transosseous and anchor techniques, although anchors have been shown to have less gap formation at the repair site. Repair augmentation with a graft may be beneficial in mid-substance injuries, chronic tears, and in cases of compromised tissue quality. Rehabilitation usually can be initiated immediately with protected weight-bearing in an orthosis, safe-zone knee passive range of motion, and avoidance of active extension. After a period of 6 weeks, rehabilitation can progress with full range of motion and a concentric strengthening program.