The effects of grade III posterolateral knee complex injuries on anterior cruciate ligament graft force. A biomechanical analysis

High prevalence of associated injuries in anterior cruciate ligament tears: A detailed magnetic resonance imaging analysis of 254 patients

OBJECTIVES

To evaluate the type and prevalence of associated injuries by using magnetic resonance imaging (MRI) in patients with anterior cruciate ligament (ACL) tears.

METHODS

Data from the Natural Corollaries and Recovery after ACL injury multicenter longitudinal cohort study were analyzed. Between May 2016 and October 2018, patients aged between 15 and 40 years, who had experienced an ACL tear within the last 6 weeks and sought medical attention at one of seven healthcare clinics in Sweden, were invited to participate. The mean time from injury to MRI was 19.6 ± 15.2 days. An orthopedic knee surgeon and a musculoskeletal radiologist reviewed all the MRI scans. The following structures were assessed: posterior cruciate ligament (PCL), medial collateral ligament (MCL) complex, lateral collateral ligament (LCL), popliteus tendon, medial meniscus (MM), lateral meniscus (LM), and cartilage. In addition, the presence of bone bruising, impaction fractures in the lateral femoral condyle (LFC) or posterolateral tibia (PLT), and Segond fractures were also assessed.  RESULTS: A total of 254 patients (48.4% males) with a mean age of 25.4 ± 7.1 years were included. The prevalence of associated injuries was as follows: PCL (0.4%), MCL {41.3% [superficial MCL and deep MCL (dMCL) 16.5%; isolated dMCL 24.8%]}, LCL (2.4%), MM (57.4%), LM (25.2%), cartilage (15.0%), bone bruising (92.9%), impaction fracture in the LFC (45.7%) and PLT (4.7%), and Segond fracture (7.5%).

CONCLUSIONS

The prevalence of associated injuries in patients with ACL tears was high. The findings reported in this study may serve as a reference tool for orthopedic surgeons and radiologists in the diagnosis of associated injuries using MRI in patients with ACL tears.

Considerations for revision anterior cruciate ligament reconstruction: A review of the current literature

Background

Failure rates among primary Anterior cruciate ligament reconstruction range from 3.2 to 11.1 %. Recently, there has been increased focus on surgical and anatomic considerations which predispose patients to failure, including excessive posterior tibial slope (PTS), unaddressed high-grade pivot shift, and improper tunnel placement.

Methods

The purpose of this review was to provide a current summary and analysis of the literature regarding patient-related and technical factors surrounding revision ACLR, rehabilitation considerations, overall outcomes, and return to sport (RTS) for patients who undergo revision ACLR.

Results

In revision ACLR patients, those receiving autografts are 2.78 times less likely to experience a re-rupture compared to patients who receive allografts. Additionally, individuals with properly positioned tunnels and removable implants are considered strong candidates for one-stage revision procedures. Conversely, cases involving primary tunnel widening of approximately 15 mm are typically indicative of two-stage revision ACLR. These findings underscore the importance of graft selection and surgical approach in optimizing outcomes for patients undergoing revision ACLR.

Conclusion

Given the high rates of revision surgery in young, active patients who return to pivoting sports, the literature recommends strong consideration of a combined ACLR + anterolateral ligament (ALL) or lateral extra-articular tenodesis (LET) procedure in this population. Unrecognized posterolateral corner (PLC) injury is a common cause of ACLR failure and current literature suggests concurrent operative management of high-grade PLC injuries. Excessive PTS has been identified as an independent risk factor for ACL graft failure. Consider revision ACLR with combined slope-reducing tibial osteotomy in cases of posterior tibial slope greater than 12°.

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.

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.

Career Length After Surgically Treated ACL Plus Collateral Ligament Injury in Elite Athletes

BACKGROUND

Limited data are available regarding career length and competition level after combined anterior cruciate ligament (ACL) and medial- or lateral-sided surgeries in elite athletes.

PURPOSE

To evaluate career length after surgical treatment of combined ACL plus medial collateral ligament (MCL) and ACL plus posterolateral corner (PLC) injuries in elite athletes and, in a subgroup analysis of male professional soccer players, to compare career length and competition level after combined ACL+MCL or ACL+PLC surgeries with a cohort who underwent isolated ACL reconstruction (ACLR).

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A consecutive cohort of elite athletes undergoing combined ACL+MCL and ACL+PLC surgery was analyzed between February 2001 and October 2019. A subgroup of male elite soccer players from this population was compared with a previously identified cohort having had isolated primary ACLR without other ligament surgery. A minimum 2-year follow-up was required. Outcome measures were career length and competition level.

RESULTS

A total of 98 elite athletes met the inclusion criteria, comprising 50 ACL+PLC and 48 ACL+MCL surgeries. The mean career length after surgical treatment of combined ACL+MCL and ACL+PLC injuries was 4.5 years. Return-to-play (RTP) time was significantly longer for ACL+PLC injuries (12.8 months; P = .019) than for ACL+MCL injuries (10.9 months). In the subgroup analysis of soccer players, a significantly lower number of players with combined ACL+PLC surgery were able to RTP (88%; P = .003) compared with 100% for ACL+MCL surgery and 97% for isolated ACLR, as well as requiring an almost 3 months longer RTP timeline (12.9 months; P = .002) when compared with the isolated ACL (10.2 months) and combined ACL+MCL (10.0 months) groups. However, career length and competition level were not significantly different between groups.

CONCLUSION

Among elite athletes, the mean career length after surgical treatment of combined ACL+MCL and ACL+PLC injuries was 4.5 years. Professional soccer players with combined ACL+PLC surgery returned at a lower rate and required a longer RTP time when compared with the players with isolated ACL or combined ACL+MCL injuries. However, those who did RTP had the same career longevity and competition level.

The 45° and 60° of sagittal femoral tunnel placement in anterior cruciate ligament reconstruction provide similar knee stability

PURPOSE

The aim of the present study was to compare 45° and 60° of sagittal femoral tunnel angles in terms of anterior tibial translation (ATT), valgus angle and graft in situ force following anterior cruciate ligament reconstruction (ACLR).

METHODS

Ten porcine knees were subjected to the following loading conditions: (1) 89 N anterior tibial load at 35° (full extension), 60° and 90° of knee flexion and (2) 5 N m valgus tibial moment at 35° and 45° of knee flexion. ATT and graft in situ force of the intact anterior cruciate ligament (ACL) and ACLR were collected using a robotic universal force/moment sensor (UFS) testing system for (1) ACL intact, (2) ACL-deficient (ACLD) and (3) two different ACLR using different sagittal femoral tunnel angles (coronal 45°/sagittal 45° and coronal 45°/sagittal 60°).

RESULTS

During the anterior tibial load, the femoral tunnel angle of ACLR knees at coronal 45°/sagittal 45° and 60° had significantly higher ATT than that of the ACL-intact knees at 60° of knee flexion (p < 0.05). The femoral tunnel angle of ACLR knees at coronal 45°/sagittal 60° had significantly lower graft in situ force than that of the ACL-intact knees at 60° and 90° of knee flexion (p < 0.05). During the valgus tibial moment, the femoral tunnel angle of ACLR knees at coronal 45°/sagittal 45° and 60° had significantly lower graft in situ force than that of the ACL-intact knees at all knee flexions (p < 0.05).

CONCLUSIONS

The femoral tunnel angle of ACLR knees at coronal 45°/sagittal 45° provided similar ATT, valgus angle and graft in situ force to that of ACLR knees at coronal 45°/sagittal 60°. Therefore, both femoral tunnel angles could be used in ACLR, as the sagittal femoral tunnel angle does not appear to be relevant in post-operative knee stability.

LEVEL OF EVIDENCE

Not applicable.

An Update on Emerging Techniques and Considerations in Revision Anterior Cruciate Ligament Reconstruction

» The rate of primary anterior cruciate ligament reconstruction (ACLR) failure in at-risk populations remains unacceptably high and necessitates thorough evaluation of native alignment and concomitant injuries.» Posterior tibial slope of >12° is a substantial risk factor of ACLR failure and should be corrected through anterior closing wedge osteotomy.» Varus malalignment of >5° exacerbates stress on the ACL graft, increases ACLR failure risks, and should be considered for correction through high tibial osteotomy at the time of revision ACLR.» Injuries to the anterolateral ligamentous complex are prevalent in ACL ruptures, and high-risk patients have shown benefit from anterolateral ligament reconstruction or lateral extra-articular tenodesis in the revision setting.» Addressing posterolateral corner, collateral ligament, and meniscal injuries, during revision ACLR, is vital to mitigate increased graft forces and optimize knee stability and functional outcomes.

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.

Autograft Versus Allograft in Posterolateral Corner Reconstruction: A Systematic Review and Meta-analysis

Background

Several approaches to surgical techniques and graft types exist in posterolateral corner (PLC) reconstruction. The literature lacks knowledge regarding outcomes after autograft versus allograft reconstruction for PLC injuries.

Purpose

To comprehensively review the current literature on PLC reconstruction and compare outcomes between autograft and allograft tissues.

Study Design

Systematic review; Level of evidence, 4.

Methods

The PubMed and Scopus online databases were searched with the terms "PLC,""posterolateral knee,""posterolateral corner," and "reconstruction" in varying combinations. Patient characteristics, graft type, graft failure, surgical techniques, functional outcome scores, and varus laxity on stress radiographs were reviewed and compared between PLC reconstruction with autografts versus allografts.

Results

Included were 22 studies comprising 33 cohorts: 16 autografts (n = 280 knees) and 17 allografts (336 knees). There were 69 isolated PLC reconstructions (58 allografts and 11 autografts) and 493 multiligament reconstructions (269 autografts and 224 allografts). There was no difference in the mean patient age (30.5 vs 33.5 years, respectively; P = .11) or mean follow-up (39.5 vs 37.7 months, respectively; P = .68) between the autograft and allograft groups. There was no evidence to suggest a difference in graft failures between graft types (pooled mean autograft vs allograft: 0.44 vs 0.41 failures; P = .95). There was a significant difference in the mean postoperative Lysholm scores for autografts versus allografts (89.6 vs 85.5, respectively; P = .04). There was no difference between the cohorts in preoperative or postoperative International Knee Documentation Committee (IKDC) scores or postoperative varus laxity.

Conclusion

Our review and meta-analysis indicated no significant differences in graft failure rates or objective outcomes after PLC reconstruction based on graft type alone. There was a significant difference in postoperative Lysholm scores in favor of the autograft group and no significant difference in IKDC subjective scores.

Outcomes After Single-Stage Anatomic Multiligament Knee Reconstruction With Early Range of Motion in Adolescents

Background

Multiligament knee injuries (MLKI), rare in adolescents, are challenging injuries that require complex surgical reconstruction. Historically, nonanatomic reconstructions have been associated with prolonged immobilization and failure to restore normal knee biomechanics, resulting in arthrofibrosis and high rates of graft failure.

Purpose

To describe the clinical and patient-reported outcomes (PROs) for adolescent patients treated with single-stage anatomic multiligament knee reconstruction.

Study Design

Case series; Level of evidence, 4.

Methods

A single-center retrospective study was performed of patients ≤18 years old who underwent reconstruction of MLKIs by a single surgeon between 2014 and 2019 using a single-stage anatomic technique, with protected weightbearing and early range of motion. Complications were defined as infection, arthrofibrosis, deep vein thrombosis (DVT) or pulmonary embolus, and secondary surgery. PROs, including the pediatric version of the International Knee Documentation Committee (Pedi-IKDC) and the Tegner activity score, were obtained at a minimum of 2 years postoperatively.

Results

Included were 30 patients (21 male, 9 female; mean age, 15.4 years). The most common ligamentous reconstruction types were anterior cruciate ligament (ACL) + fibular collateral ligament (12 patients; 40%) and ACL + medial collateral ligament (9 patients; 30%). Three patients (10%) had secondary surgeries, including irrigation and debridement of a granuloma, a staged osteochondral allograft transplantation to a lateral femoral condyle impaction fracture, and repair of a medial meniscal tear and lateral femoral condyle fracture associated with new injuries 2 years after ACL + fibular collateral ligament reconstruction. Two patients (7%) developed arthrofibrosis and 1 patient (3%) developed DVT. PRO scores obtained at a mean of 37 months postoperatively included a mean Pedi-IKDC of 87 (range, 52-92) and a median highest Tegner score at any point postoperatively of 9 (range, 5-10). Of the patients who were athletes before their injury, 70% returned to the same or higher level of sport postoperatively.

Conclusion

Reconstruction of MLKI in this series of adolescents with single-stage anatomic techniques and early range of motion resulted in low rates of secondary surgery, few complications, and good knee function as well as PRO scores at mean 3-year follow-up.

Demystifying the "Dark Side of the Knee": An Update on Imaging of the Posterolateral Corner

The posterolateral corner (PLC) of the knee is a complex anatomical-functional unit that includes ligamentous and tendinous structures that are crucial for joint stability. This review discusses the intricate anatomy, biomechanics, and imaging modalities, as well as the current challenges in diagnosing PLC injuries, with an emphasis on magnetic resonance imaging (MRI). Recognizing the normal MRI anatomy is critical in identifying abnormalities and guiding effective treatment strategies. Identification of the smaller structures of the PLC, traditionally difficult to depict on imaging, may not be necessary to diagnose a clinically significant PLC injury. Injuries to the PLC, often associated with cruciate ligament tears, should be promptly identified because failure to recognize them may result in persistent instability, secondary osteoarthritis, and cruciate graft failure.

There Is No Difference in Clinical Outcomes of Tibial-Based Versus Fibular-Based Posterolateral Corner Reconstruction: A Systematic Review

PURPOSE

To evaluate and analyze the current literature regarding clinical outcomes after posterolateral corner reconstruction (PLCR) using fibular-based and tibial-based techniques.

METHODS

A systematic review of the literature was performed to evaluate patient-reported outcomes after PLCR. Embase, PubMed, and Scopus were searched from their respective inception through October 25, 2022. Studies containing patient-reported outcome scores of tibial and fibular-based PLCR were included. Outcomes collected from each study were summarized using t tests for consistently reported Tegner, Lysholm, and International Knee Documentation Committee Score.

RESULTS

Twenty-four studies (16 with level of evidence IV, 6 with Level III, and 2 with Level II) met the inclusion criteria and included 669 patients in total. Four studies comprising 111 patients directly compared the results of tibial- and fibular-based PLCR. Mean clinical follow-up across all studies was 3.3 years. The 4 studies that reported on both tibial and fibular-based PLCR were found to have no significant differences in patient-reported outcomes with P values ranging from .0561 to .9881.

CONCLUSIONS

Analysis of the available literature regarding tibial- and fibular-based posterolateral corner reconstruction suggests no clinical differences.

LEVEL OF EVIDENCE

Level II-IV, review of systematic studies.

Evaluation of Failed ACL Reconstruction: An Updated Review

Failure rates among primary Anterior Cruciate Ligament Reconstruction (ACLR) range from 3.2% to 11.1%. Recently, there has been increased focus on surgical and anatomic considerations which predispose patients to failure, including excessive posterior tibial slope (PTS), unaddressed high-grade pivot shift, and improper tunnel placement. The purpose of this review was to provide a current summary and analysis of the literature regarding patient-related and technical factors surrounding revision ACLR, rehabilitation considerations, overall outcomes and return to sport (RTS) for patients who undergo revision ACLR. There is a convincingly higher re-tear and revision rate in patients who undergo ACLR with allograft than autograft, especially amongst the young, athletic population. Unrecognized Posterior Cruciate Ligament (PLC) injury is a common cause of ACLR failure and current literature suggests concurrent operative management of high-grade PLC injuries. Given the high rates of revision surgery in young active patients who return to pivoting sports, the authors recommend strong consideration of a combined ACLR + Anterolateral Ligament (ALL) or Lateral extra-articular tenodesis (LET) procedure in this population. Excessive PTS has been identified as an independent risk factor for ACL graft failure. Careful consideration of patient-specific factors such as age and activity level may influence the success of ACL reconstruction. Additional technical considerations including graft choice and fixation method, tunnel position, evaluation of concomitant posterolateral corner and high-grade pivot shift injuries, and the role of excessive posterior tibial slope may play a significant role in preventing failure.

Anatomic Anterolateral Ligament Reconstruction with Iliotibial Band Graft and Concomitant Anterior Cruciate Ligament Reconstruction

Anterior cruciate ligament (ACL) reconstruction (ACLR) attempts to restore native ACL function. Persistent anterolateral instability is a common symptom after ACLR that can lead to worse patient outcomes. Additional surgeries, like anterolateral ligament reconstruction (ALLR), can augment the ACL graft and help increase anterolateral rotational stability. Certain indications for ACLR with ALLR include high-grade pivot shift, increased posterior tibial slope (>12°), revision ACLR, and concomitant ligamentous or meniscal injuries. We describe an anatomic ALLR technique using an 8 cm long × 1 cm wide strip of the inferior aspect of the iliotibial band fixed at the native attachment sites of the ALL.

The relationship of proximal lateral collateral ligament hyperintensity with knee joint ligament and meniscus pathologies

BACKGROUND

Hyperintensity in the proximal lateral collateral ligament (LCL) is often confusing. This appearance may be alone or accompany other pathologies.

PURPOSE

To investigate the relationship between the signal intensity (SI) change in the proximal LCL and the knee joint pathologies.

MATERIAL AND METHODS

The knee MRI scans taken between 2020 and 2022 were queried retrospectively. Patients with acute trauma, instability, knee surgery, or high-grade osteoarthritis were excluded. Included patients were divided into two groups as normal SI and increased SI according to proximal LCL. The difference in ligamentous and meniscal pathologies between the two groups was analyzed using a chi-square test. Inter-observer agreement analysis was performed on 50 randomly selected patients.

RESULTS

A total of 351 patients (139 men [39.6%], 212 women [60.4%]; median age = 37 years; interquartile range = 67 years) were included. There were 114 (32.5%) LCLs with normal SI and 237 (67.5%) LCLs with increased SI. Normal SI and increased SI groups had a significant difference in terms of joint side, median age, patellar tendon SI, anterior cruciate ligament SI, and medial collateral ligament SI (P = 0.004, P = 0.004, P = 0.001, P = 0.011, P = 0.004, respectively). A significant difference between the results of two separate LCL examinations in coronal + axial and coronal-only planes (P <0.001). Inter-observer agreement was found to be good to excellent.

CONCLUSION

Hyperintensity in the proximal LCL was more common on the right joint side, in older patients, and patients with hyperintensity in the proximal patellar tendon, anterior cruciate ligament, and medial collateral ligament. Evaluating the LCL only in the coronal plane overestimates the hyperintensity.

Higher success rate observed in reconstruction techniques of acute posterolateral corner knee injuries as compared to repair: an updated systematic review

PURPOSE

There remains controversy regarding the optimal surgical treatment for acute complete (grade III) posterolateral corner (PLC) injuries. The purpose of this article is to systematically review the contemporary literature regarding surgical options and subsequent outcomes of acute grade III PLC injuries.

METHODS

A systematic review was performed using the following search terms: posterolateral corner knee, posterolateral knee, posterolateral instability, multi-ligament knee, and knee dislocation. Inclusion criteria consisted of studies with level I-IV evidence, reporting on human patients with acute grade III PLC injuries undergoing operative management within 4 weeks from injury, with subjective and/or objective outcomes (including varus stress examinations or varus stress radiographs) reported at a minimum 2-year follow-up. Two investigators independently performed the search by sequentially screening articles. Accepted definitions of varus stability on examination or stress radiographs and revision surgery were used to determine success and failure of treatment.

RESULTS

A total of 12 studies, consisting of 288 patients were included. Ten studies reported primary repair, while reconstruction techniques were reported in seven studies. Overall, 43% (n = 125/288) of injuries involved the PLC, ACL and PCL. Staged reconstruction was reported in 25% (n = 3/12) of studies. The Lysholm score was the most commonly reported outcome measure. An overall failure rate of 12.4% (n = 35/282) was observed. Surgical failure was significantly higher in patients undergoing repair (21.9%; n = 21/96) compared to reconstruction (7.1%; n = 6/84) (p = 0.0058). Return to sport was greater in patients undergoing reconstruction (100%; n = 22/22) compared to repair (94%; n = 48/51) (n.s). The most common post-operative complication was arthrofibrosis requiring manipulation under anesthesia (8.7%; n = 25/288). A total of 3.8% (n = 11/288) of patients underwent revision PLC reconstruction.

CONCLUSION

There remains substantial heterogeneity in the surgical techniques of acute, grade III PLC injuries with an overall failure rate of 12.4%. Failure rates were significantly lower, and return to sport rates higher in patients undergoing PLC reconstruction compared to repair. The most common postoperative complication was arthrofibrosis requiring manipulation under anesthesia.

LEVEL OF EVIDENCE

Level IV.

Injury Patterns in Posterolateral Corner Knee Injury

Background

Posterolateral corner (PLC) knee injuries associated with different injury mechanisms are not well known.

Purpose/Hypothesis

This study sought to assess the patterns of associated injuries in the setting of PLC injury. The hypothesis was that there are recognizable injury patterns in PLC injuries that may correlate with injury mechanism.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

Patients who sustained a multiligament knee injury were retrospectively reviewed. Patients who sustained an acute grade 3 PLC injury and underwent surgery were enrolled in this study. A description of the PLC injury (location of the injury of the fibular collateral ligament [FCL], popliteus tendon, and/or popliteofibular ligament) and reported concomitant injuries (biceps femoris tendon or meniscal tears, cartilage pathology and/or peroneal nerve palsy, or bone bruises) were collected and classified based on intraoperative and magnetic resonance imaging (MRI) findings.

Results

Of 135 patients reviewed, 83 did not have PLC involvement and 13 were excluded due to insufficient MRI scans available. Thus, 39 patients were included in this study. For both the anterior cruciate ligament (ACL)-PLC and ACL-posterior cruciate ligament-PLC injury patterns, the most frequent injury pattern entailed a bone bruise of the anteromedial (AM) femur and tibia, an FCL tear from the fibular head, the popliteus tendon avulsed off the femur, a biceps femoris tendon torn off the fibular head, and a common peroneal nerve palsy. Conversely, when no bone bruise occurred on the AM femur and tibia, the FCL was injured on the femoral side and the popliteus tendon, biceps femoris, and peroneal nerve were not injured.

Conclusion

AM bone bruise was associated with a peroneal nerve injury in almost half of the patients, and peroneal nerve injury was not seen if there was no AM bone bruise.

Revision anterior cruciate ligament reconstruction

Anterior cruciate ligament (ACL) graft failure from rupture, attenuation, or malposition may cause recurrent subjective instability and objective laxity, and occurs in 3% to 22% of ACL reconstruction (ACLr) procedures. Revision ACLr is often indicated to restore knee stability, improve knee function, and facilitate return to cutting and pivoting activities. Prior to reconstruction, a thorough clinical and diagnostic evaluation is required to identify factors that may have predisposed an individual to recurrent ACL injury, appreciate concurrent intra-articular pathology, and select the optimal graft for revision reconstruction. Single-stage revision can be successful, although a staged approach may be used when optimal tunnel placement is not possible due to the position and/or widening of previous tunnels. Revision ACLr often involves concomitant procedures such as meniscal/chondral treatment, lateral extra-articular augmentation, and/or osteotomy. Although revision ACLr reliably restores knee stability and function, clinical outcomes and reoperation rates are worse than for primary ACLr.

The Role of the Medial Meniscus in Anterior Knee Stability

BACKGROUND

Few studies have compared the force distribution between the anterolateral, posterolateral, and medial structures of the knee.

PURPOSE

To investigate the important structures in an intact knee contributing to force distribution in response to anterior tibial load.

STUDY DESIGN

Controlled laboratory study.

METHODS

Nine fresh-frozen cadaveric knee specimens underwent robotic testing. First, 100 N of anterior tibial load was applied to the intact knee at 0°, 15°, 30°, 60°, and 90° of knee flexion. The anterior cruciate ligament (ACL), anterolateral capsule, lateral collateral ligament, popliteal tendon, posterior root of the lateral meniscus, superficial medial collateral ligament, posterior root of the medial meniscus (MM), and posterior cruciate ligament were then completely transected in sequential order. After each transection, the authors reproduced the intact knee motion when a 100-N anterior tibial load was applied. By applying the principle of superposition, the resultant force of each structure was determined based on the 6 degrees of freedom force/torque data of each state.

RESULTS

At every measured knee flexion angle, the resultant force of the ACL was the largest of the tested structures. At knee flexion angles of 60° and 90°, the resultant force of the MM was larger than that of all other structures with the exception of the ACL.

CONCLUSION

The MM was identified as playing an important role in response to anterior tibial load at 60° and 90° of flexion.

CLINICAL RELEVANCE

In clinical settings, the ACL of patients with a poorly functioning MM, such as tear of the MM posterior root, should be monitored considering the large resultant force in response to an anterior tibial load.

Repair of Acute Grade 3 Combined Posterolateral Corner Avulsion Injuries Using an Enhanced Fixation Technique

Background

Previous studies have suggested that surgical repair of the posterolateral corner (PLC) may be inferior to reconstruction.

Hypothesis

We hypothesized that acute repair (<3 weeks) of avulsion-type PLC multiligament knee injuries with no midsubstance injury would lead to lower failure rates than previously reported for PLC repair.

Study Design

Case series; Level of evidence, 4.

Methods

A total of 28 patients with multiligament knee injuries who underwent acute repair between January 2007 and June 2018 of a PLC avulsion injury with no evidence of midsubstance tearing were included. All PLC avulsion injuries were treated using a transosseous Krackow suture pull-through technique without graft augmentation. Outcome metrics included lateral joint-space widening with varus stress, patient-reported clinical varus instability, patient-reported outcome measures (PROMs), and any subsequent revision or salvage procedure.

Results

The mean time from injury to repair was 8.1 ± 5 days. At a mean follow-up of 2 years (range, 3-90 months), clinical varus stress examination at 30° demonstrated a significant reduction in lateral compartment opening, from 9 ± 3 mm preoperatively to 0 ± 3 mm (P < .0001). The failure rate was calculated to be 10.7% (3/28), which was significantly lower than the failure rate from a 2016 systematic review (38%, 17/45; P = .015). Of the 28 patients, 21 (75%) had PROM scores. Patients who underwent staged bi-cruciate reconstructions (n = 5) had significantly higher subjective International Knee Documentation Committee (IKDC) (87.2 vs 65.5; P = .014) and Lysholm (90.5 vs 75.2; P = .029) scores compared to patients with untreated bi-cruciate injuries (n = 9). Patients with peroneal nerve injury (n = 4) had significantly lower IKDC (58.2 vs 80.8; P = .0045) and Tegner (3.2 vs 5.4; P = .047) scores than those without peroneal nerve injury (n = 17). The mean IKDC and Lysholm scores at final follow-up were 73.4 ± 24.0 and 80.8 ± 23.1 at 7.1 years (range, 2.3-10.6 years) of follow-up.

Conclusion

Repair of acute grade 3 combined PLC avulsion injuries using a transosseous Krackow suture pull-through technique demonstrated a failure rate of 10.7%. Patients who underwent a staged cruciate reconstruction(s) had higher subjective outcome scores than those who had cruciate injuries left untreated. Peroneal nerve injury was associated with lower outcome scores.

The value of magnetic resonance imaging in the preoperative diagnosis of tibial plateau fractures: a systematic literature review

Purpose

The outcome of a tibial plateau fracture (TPF) depends on the fracture reduction achieved and the extent of soft-tissue lesions, including lesions in the ligaments, cartilage, and menisci. Sub-optimal treatment can result in poor knee function and osteoarthritis. Preoperative planning is primarily based on conventional X-ray and computed tomography (CT), which are unsuitable for diagnosing soft-tissue lesions. Magnetic resonance imaging (MRI) is not routinely performed. To date, no literature exists that clearly states the indications for preoperative MRI. This systematic review aimed to determine the frequency of soft-tissue lesions in TPFs, the association between fracture type and soft-tissue lesions, and the types of cases for which MRI is indicated.

Methods

A systematic review of the literature was based on articles located in PubMed/MEDLINE and the Cochrane Central Register of Controlled Trials (CENTRAL), supplemented by searching the included articles’ reference lists and the ePublication lists of leading orthopedic and trauma journals.

Results

A total of 1138 studies were retrieved. Of these, 18 met the eligibility criteria and included a total of 877 patients. The proportion of total soft-tissue lesions was 93.0%. The proportions of soft-tissue lesions were as follows: medial collateral ligament 20.7%, lateral collateral ligament 22.9%, anterior cruciate ligament 36.8%, posterior cruciate ligament 14.8%, lateral meniscus 48.9%, and medial meniscus 24.5%. A weak association was found between increasing frequency of LCL and ACL lesions and an increase in fracture type according to Schatzker's classification. No standard algorithm for MRI scans of TPFs was found.

Conclusion

At least one ligament or meniscal lesion is present in 93.0% of TPF cases. More studies with higher levels of evidence are needed to find out in which particular cases MRI adds value. However, MRI is recommended, at least in young patients and cases of high-energy trauma.

Editorial Commentary: Magnetic Resonance Imaging Is Helpful in Predicting High-Grade Knee Rotatory Instability: But When in Doubt, Always Examine the Patient

Unrecognized rotatory instability as evidenced by a high-grade pivot shift is well known to compromise anterior cruciate ligament (ACL) reconstruction results. By measuring which patients have anterior tibial subluxation of the lateral compartment ≥ 6 mm on a preoperative MRI, surgeons may be better able to counsel patients on postoperative expectations, as well as prepare for additional procedures to treat high-grade rotatory instability. Additionally, as there is an increased incidence of lateral meniscus tears in high-grade rotatory ACL lesions, surgeons should be vigilant and prepared to repair lateral meniscus root and ramp lesions. Furthermore, early identification of those patients with anterior tibial subluxation of the lateral compartment ≥6 mm will provide the opportunity for early surgery, as it is known that patients with high-grade rotatory instability are likely to sustain further intra-articular damage and have poorer outcomes if surgery is delayed. However, when there is doubt of high-grade rotatory instability after an ACL injury, examining the patient with a pivot shift maneuver should still be the "gold standard".

Effect of modified Laprade technique on posterolateral ligament injury of knee

Purpose

To investigate the effect of modified Laprade technique on the reconstruction of posterolateral structure of knee and anterolateral ligament of knee in the treatment of posterolateral injury of knee.

Methods

From December 2013 to June 2020, multiple ligament injury patients who received surgery in our hospital were collected in this research. These patients underwent a modified Laprade technique for posterolateral structural reconstruction of the knee. Lysholm scores of patients pre- and post-operation were recorded.

Result

The operations of the observation group or the control group patients were completed. There were no significant differences in gender, age, preoperative knee range of motion and preoperative Lysholm score. At the time of follow-up 1 month after operation, there was no significant difference in knee range of motion, dial-up test angle and Lysholm score between the observation and the control group. When followed up 1 year after operation, the Lysholm score of the observation group was higher than that of the control group. The difference was statistically significant. The same situation occurred in the range of motion of the knee in both groups. However, there was still no significant difference between the two groups in the dial-up test 1 year after operation, whether the knee flexion was 30° or 90°.

Conclusion

For patients with posterolateral structure injury of knee, the modified Laprade technique is a feasible surgical technique.

Relationship between the height of fibular head and the incidence and severity of knee osteoarthritis

The purpose of this study was to investigate the correlation between fibular head height and the incidence and severity of osteoarthritis associated with varus knee deformity. The fibular head height, joint line convergence angle (JLCA) and medial proximal tibial angle (MPTA) were measured in a three-dimensional model. Ordinal multivariate logistic regression was used to analyze the correlation between fibular head height and Kellgren–Lawrence (K–L) grade. Pearson correlation was used to analyze the correlation between fibular head height and K–L grade. A total of 232 patients (232 knees) were finally included in the study. There were significant differences in JLCA and hip–knee–ankle angle (P < 0.05), and both JLCA and hip–knee–ankle angle increased with severe aggravation of K–L grade. Both fibular head height and MPTA decreased as the K–L grade was severely aggravated. There was a significant negative correlation between K–L grade and fibular head height (r = −0.812, P < 0.001). Furthermore, there was a significant negative correlation between fibular head height and hip–knee–ankle angle (r = −0.7905, P < 0.001). In addition to body mass index, fibular head height is a risk factor for the pathogenesis of osteoarthritis associated with varus knee deformity; the smaller the fibular head height, the more severe the degree of varus deformity.

Effect of Sectioning of the Anterior Cruciate Ligament and Posterolateral Structures on Lateral Compartment Gapping: A Randomized Biomechanical Study

Background:

The contribution of anterior cruciate ligament (ACL) injury to lateral instability under varus stress, particularly compared with posterolateral structures, is not well known.

Purpose:

To investigate the effect of sectioning the ACL and posterolateral knee structures on lateral compartment gapping under varus stress.

Study Design:

Controlled laboratory study.

Methods:

Fourteen nonpaired cadaveric knees were randomized to 1 of 2 groups: sequential sectioning of the ACL, fibular collateral ligament (FCL), popliteus tendon (PLT), and popliteofibular ligament (PFL) (ACL-first group) or sequential sectioning of the FCL, PLT, PFL, and ACL (FCL-first group). Knees were loaded onto a custom jig at a 20° flexion angle. A standardized 12-N·m varus moment was applied to each specimen in the intact state and after each randomized sequential-sectioning state. Lateral compartment opening was measured on radiographs to assess the contribution to the increase in the lateral gap caused by resecting the respective structure. The distance was measured by 3 observers on 15 images (5 testing states each imaged 3 times) per specimen, for a total of 210 radiographs. The articular cartilage surfaces were not included in the measurements.

Results:

The mean increase in lateral opening after sectioning all structures (ACL and posterolateral corner) was 4.6 ± 1.8 mm (range, 1.9-7.7 mm). The ACL and FCL sectioning contributed the most to lateral knee opening (1.3 ± 0.6 and 2.2 ± 1.3 mm, respectively). In both groups, lateral gapping >3 mm was achieved only after both the ACL and FCL were sectioned. All comparisons of increased mean gapping distances demonstrated a significant difference with subsequent sequential sectioning of structures, except comparisons between the FCL and PLT and the PLT and PFL. When considering the effect of the ACL on lateral opening, no significant difference was found between sectioning the ACL first or FCL first (P = .387).

Conclusion:

ACL deficiency significantly increased lateral opening under varus stress, regardless of the sequence of injury. The effect of injury to the ACL in addition to the lateral structures should be considered when using varus stress radiographs to evaluate knee injuries.

Clinical Relevance:

With the current findings, understanding the effect of ACL and posterolateral corner injuries on lateral gapping under varus stress can aid in correctly diagnosing knee injuries and determining appropriate treatment plans.

Meniscal Tears, Posterolateral and Posteromedial Corner Injuries, Increased Coronal Plane, and Increased Sagittal Plane Tibial Slope All Influence Anterior Cruciate Ligament-Related Knee Kinematics and Increase Forces on the Native and Reconstructed Anterior Cruciate Ligament: A Systematic Review of Cadaveric Studies

PURPOSE

To obtain a comprehensive list of pathologies that cause increased anterior cruciate ligament (ACL) forces and pathologic knee kinematics to evaluate for in both primary and revision ACL reconstruction to decrease the risk of subsequent graft overload.

METHODS

An electronic search was performed in the Embase and MEDLINE databases for the period between January 1, 1990, and December 10, 2020. All articles investigating medial and lateral meniscal injury, (postero)lateral corner injury, (postero)medial corner/medial collateral ligament injury, valgus alignment, varus alignment, and tibial slope in relation to ACL (graft) force and knee kinematics were included.

RESULTS

Data of 43 studies were included. The studies reported that high-volume medial and lateral meniscectomies, peripheral meniscus tears, medial meniscus ramp tears, lateral meniscus root tears, posterolateral corner injuries, medial collateral ligament tears, increased tibial slope, and valgus and varus alignment were reported to have a significant impact on ACL (graft) force and related knee kinematics.

CONCLUSIONS

This systematic review on biomechanical cadaver studies provides a rationale to systematically identify and treat pathologies in ACL-injured knees, because when undiagnosed or left untreated, these specific concomitant pathologies could lead to ACL graft overload in both primary and revision ACL-reconstructed knees.

CLINICAL RELEVANCE

it is necessary that orthopaedic surgeons who treat ACL-injured knees understand the surgically relevant biomechanical consequences of additional pathologies and use this knowledge to optimize treatment in ACL-injured patients.

Posterolateral Corner Reconstruction of the Knee Using Gracilis Autograft and Biceps Femoris

We introduce our technique for posterolateral corner reconstruction, which is based on the principle described in Arciero's technique for anatomic reconstruction of lateral collateral ligament (LCL) and popliteofibular ligament (PFL) to gain static stability in varus strain and external rotation. This technique uses a doubled gracilis autograft to reconstruct the PFL and a split biceps tendon transfer to reconstruct the LCL. Using this technique an anatomical LCL and PFL reconstruction can be performed in combination with anterior cruciate ligament or posterior cruciate ligament reconstruction without contralateral graft harvest or allograft. The technique also enables an isolated reconstruction of LCL or PFL when required and can be performed to augment an acute repair.

Elongation Patterns of Posterolateral Corner Reconstruction Techniques: Results Using 3-Dimensional Weightbearing Computed Tomography Simulation

Background:

The isometric characteristics of nonanatomic and anatomic posterolateral corner (PLC) reconstruction techniques under weightbearing conditions remain unclear.

Purpose:

To (1) simulate graft elongation patterns during knee flexion for 3 different PLC reconstruction techniques (Larson, Arciero, and LaPrade) and (2) compute the most isometric insertion points of the fibular collateral ligament (FCL) graft strands for each technique and report quantitative radiographic landmarks.

Study Design:

Descriptive laboratory study.

Methods:

The authors performed a 3-dimensional simulation of 10 healthy knees from 0° to 120° of flexion using weightbearing computed tomography (CT) scans. The simulation was used to calculate ligament length changes during knee flexion for the PLC reconstruction techniques of Larson (nonanatomic single-bundle fibular sling reconstruction), Arciero (anatomic reconstruction with additional popliteofibular ligament graft strand), and LaPrade (anatomic reconstruction with popliteofibular ligament graft strand and popliteus tendon graft strand). The most isometric femoral insertion points for the FCL graft strands were computed within a 10-mm radius around the lateral epicondyle (LE), using an automatic string generation algorithm (0 indicating perfect isometry). Radiographic landmarks for the most isometric points were reported.

Results:

Median graft lengthening during knee flexion was similar for the anterior graft strands of all 3 techniques. The posterior graft strands demonstrated significant differences, from lengthening for the Arciero (9.9 mm [range, 6.7 to 15.9 mm]) and LaPrade (10.2 mm [range, 4.1 to 19.7 mm]) techniques to shortening for the Larson technique (−17.1 mm [range, −9.3 to −22.3 mm]; P < .0010). The most isometric point for the FCL graft strands of all techniques was located at a median of 2.2 mm (range, −2.2 to 4.5 mm) posterior and 0.3 mm (range, −1.8 to 3.7 mm) distal to the LE.

Conclusion:

Overconstraint can be avoided by tensioning the posterior graft strands in the Larson technique in extension, and in the Arciero and LaPrade techniques at a minimum of 60° of knee flexion. The most isometric point was located posterodistal to the LE.

Clinical Relevance:

The described isometric behavior of nonanatomic and anatomic PLC reconstruction techniques can guide optimal surgical reconstruction and prevent graft lengthening and overconstraint of the lateral compartment in knee flexion. Repetitive graft lengthening has been found to be associated with graft failure, and overconstraint favors lateral compartment pressure and cartilage degeneration.

Determining the Roles of the Anterior Cruciate Ligament, Posterolateral Corner, and Medial Collateral Ligament in Knee Hyperextension Using the Heel-Height Test

Background:

Anterior cruciate ligament (ACL) tears are often associated with other ligamentous injuries. The side-to-side difference in heel height can represent a valuable diagnostic tool in the setting of multiligamentous injuries.

Purpose:

To assess in a cadaveric model how sequential sectioning of the static stabilizing structures of the knee (ACL, fibular collateral ligament [FCL], popliteus tendon [PLT], popliteofibular ligament [PFL], and medial collateral ligament [MCL]) influences heel-height measurements when comparing groups undergoing initial transection of the ACL versus FCL and to assess posterior tibial slope after sequential sectioning.

Study Design:

Controlled laboratory study.

Methods:

A total of 16 fresh cadaveric knees were carefully dissected to expose the ACL, FCL, PLT, PFL, and MCL. Each knee was randomized to either the ACL-first or FCL-first group based on the initial structure sectioned. The sectioning order was as follows: (1) ACL or FCL, (2) FCL or ACL, (3) PLT, (4) PFL, and (5) MCL. Heel height was measured with a standardized superiorly directed 12-N·m force applied to the knee while stabilizing the femur; heel height was also measured with a clinician-applied force. The measurements were compared between and within groups for each sectioned state. The correlation between tibial slope and heel-height measurements was analyzed.

Results:

There were no significant differences in heel-height measurements between the ACL-first and FCL-first groups (P = .863). Combined ACL-FCL injuries led to a 2.85 ± 0.83–cm increase in heel height compared to the intact state. Significant increases in heel height occurred after all sectioned states, except the PFL sectioned state. Combined ACL–posterolateral corner (PLC) injuries resulted in a 3.72 ± 1.02–cm increase in heel height, and additional sectioning of the MCL resulted in a 4.73 ± 1.35–cm increase compared to the intact state. Tibial slope was not correlated with increases in heel height after each sectioning (P = .154).

Conclusion:

Combined ACL-FCL, ACL-PLC, and ACL-PLC-MCL injuries resulted in increasing mean heel-height measurements (2.85, 3.72, and 4.73 cm, respectively) compared to the intact state. Tibial slope was not found to influence increases in heel height.

Clinical Relevance:

The side-to-side difference in heel height may be a clinically relevant examination tool for diagnosing multiligament knee injuries.

Sequential damage assessment of the posterolateral complex of the knee joint: a finite element study

BACKGROUND

The posterolateral complex (PLC), which consists of the popliteus tendon (PT), lateral collateral ligament (LCL), and popliteofibular ligament (PFL), is an indispensable structure of the knee joint. The aim of this study was to explore the functionality of the PLC by determining the specific role of each component in maintaining posterolateral knee stability.

METHODS

A finite element (FE) model was generated based on previous material property data and magnetic resonance imaging of a volunteer's knee joint. The injury order of the PLC was set as LCL, PFL, and PT. A combined compressive load of 1150 N and an anterior tibial load of 134 N was applied to the tibia to investigate tibial displacement (TD). Tibial external rotation (TER) and tibial varus angulation (TVA) were measured under bending motions of 5 and 10 Nm. The instantaneous axis of rotation (IAR) of the knee joint under different rotation motions was also recorded.

RESULTS

The TD of the intact knee under a combined compressive load of 1150 N and an anterior tibial load of 134 N matched the values determined in previous studies. Our model showed consistent increases in TD, TVA, and TER after sequential damage of the PLC. In addition, sequential disruption caused the IAR to shift superiorly and laterally during varus rotation and medially and anteriorly during external rotation. In the dynamic damage of the PLC, LCL injury had the largest effect on TD, TVA, TER, and IAR.

CONCLUSIONS

Sequential injury of the PLC caused considerable loss of stability of the knee joint according to an FE model. The most significant structure of the PLC was the LCL.

Minimizing the risk of graft failure after anterior cruciate ligament reconstruction in athletes. A narrative review of the current evidence

Anterior cruciate ligament (ACL) tear is one of the most common sport-related injuries and the request for ACL reconstructions is increasing nowadays. Unfortunately, ACL graft failures are reported in up to 34.2% in athletes, representing a traumatic and career-threatening event. It can be convenient to understand the various risk factors for ACL failure, in order to properly inform the patients about the expected outcomes and to minimize the chance of poor results. In literature, a multitude of studies have been performed on the failure risks after ACL reconstruction, but the huge amount of data may generate much confusion.The aim of this review is to resume the data collected from literature on the risk of graft failure after ACL reconstruction in athletes, focusing on the following three key points: individuate the predisposing factors to ACL reconstruction failure, analyze surgical aspects which may have significant impact on outcomes, highlight the current criteria regarding safe return to sport after ACL reconstruction.

Tunnel Convergence Rate in Combined Anteromedial Portal Anterior Cruciate Ligament and Anterolateral Structure Reconstructions Is Influenced by Anterior Cruciate Ligament Knee Flexion Angle, Tunnel Position, and Direction

PURPOSE

The goal of the present study was to evaluate a potential tunnel convergence in combined anterior cruciate ligament (ACL) reconstruction using the anteromedial portal technique and lateral extra-articular tenodesis (LET).

METHODS

Ten fresh frozen femora were dissected and a K-wires were inserted into the middle of the ACL stump, according to an ACL reconstruction at 110° and 140° knee flexion. ACL reconstruction at 120° and 130° was simulated. Seven K-wires with different femoral insertion sites and angulations were drilled into the lateral femoral condyle relative to the lateral epicondyle (E3: 8 mm proximal and 4 mm posterior; E1: 5 mm proximal and 5 mm anterior and E2: over-the-top position). Tunnel conflict rate was evaluated using a measuring arm and a metrology software.

RESULTS

Drilling the femoral ACL tunnel in low knee flexion (110°-120°) significantly (P < .001) reduced the tunnel conflict rate compared to the ACL drilled in high knee flexion (130°-140°). Changing the insertion point from proximal and posterior (E3) to proximal and anterior (E1) showed a reduced tunnel conflict rate from 40 ± 21.2% to 15 ± 26% and no tunnel conflict for an ACL drilled at 110°-130° knee flexion.

CONCLUSION

A possible tunnel conflict in simultaneous ACL reconstruction using the AMP technique and LET was dependent on ACL knee flexion angle, LET insertion site, and angulation. This posed the dilemma that no generally applicable LET configuration could be recommended to avoid a tunnel conflict. However, it appears that an insertion point located proximal and anterior to the lateral epicondyle results in less tunnel conflicts than an insertion point located proximal and posterior.

CLINICAL RELEVANCE

An insertion point located proximal and anterior to the lateral epicondyle with a 30° proximal and 30° anterior angulation could reliably avoid a tunnel conflict when the ACL was drilled between 110 and 130° using a low anteromedial portal.

Editorial Commentary: Indications for Lateral Extra-Articular Tenodesis in Primary Anterior Cruciate Ligament Reconstruction

Lateral extra-articular tenodesis and other anterolateral procedures improve patient outcomes when combined with anterior cruciate ligament reconstruction. Failure rates are >50% lower in young patients at high risk of reinjury. We defined patients at high risk as those aged 14 to 25 years with 2 or more factors of the following criteria: 1) returning to contact pivoting sport, 2) high-grade anterolateral rotatory laxity, as measured by pivot shift test (grade 2 or higher), and 3) generalized ligamentous laxity (Beighton score greater than 4) or knee hyperextension recurvatum of greater than 10°. Other indications may include Segond fracture, chronic anterior cruciate ligament lesion, radiographic lateral femoral notch sign, and lateral coronal plane laxity. A clearer understanding of indications determined by a comprehensive clinical assessment and risk stratification is needed. As indications continue to be "stretched," we need to better understand the role of lateral extra-articular tenodesis and when to employ it in our practice.

The popliteofibular ligament: a cadaveric ultrasound study

OBJECTIVE

The popliteofibular ligament (PFL) is an important stabilizer of the knee found within the posterolateral corner (PLC) of the joint. Injuries to the PLC can cause substantial patient morbidity. Accurate PFL visualization has been historically challenging, impeding injury diagnosis and treatment. The gold standard for in vivo PFL visualization is magnetic resonance imaging (MRI), but this procedure has slice thickness limitations, is costly, and is subject to longer wait times. Ultrasonographic (US) PFL assessment is a potentially viable alternative to MRI. This study aimed to determine the viability of US PFL assessment.

MATERIALS AND METHODS

Ten fresh-frozen lower limb specimens were evaluated for the presence and morphometric characteristics of the PFL via US using an 18.0-MHz linear transducer. The cadavers were then dissected and reassessed for the presence and morphometric characteristics of the PFLs for comparison with US findings. Moreover, the fracture of the fibular styloid process near the site of the insertion of the PFL (the arcuate sign) was simulated and assessed via US.

RESULTS

The PFL was visualized and measured in all ten knees via both US and cadaveric assessments. There were no statistically significant differences in PFL morphometric characteristics determined via US examination and dissection. The fibular styloid fracture was easily identified in US examination.

CONCLUSION

US imaging is a viable alternative for accurate and effective assessment of the normal PFL. Moreover, the arcuate sign can be evaluated via US.

Comparable Subjective and Objective Clinical Outcomes After Fibular or Combined Tibial-Fibular-based Reconstruction of the Posterolateral Corner of the Knee: A Systematic Review and Meta-analysis

INTRODUCTION

To compare subjective and objective outcomes of fibular and combined tibial-fibular (TF)-based posterolateral corner (PLC) reconstruction.

METHODS

A systematic review of literature reporting outcomes of posterolateral corner reconstruction was conducted including outcome studies of surgically treated PLC injuries with a minimum 1-year follow-up, postoperative subjective and objective outcomes including the patient-reported outcome scorings of Lysholm score, International Knee Documentation Committee evaluation (subjective and objective), dial test, and varus stress radiographs.

RESULTS

The 32 studies included comprised 40 cohorts: 12 cohorts (n = 350 knees) used a fibular-based technique, and 28 cohorts (n = 593 knees) used a combined TF-based technique. No statistically significant differences were found in patient-reported outcomes or objective clinical measurements comparing the two techniques using the Lysholm score (P = 0.204, τ2 = 3.46), International Knee Documentation Committee evaluation (subjective P = 0.21 τ2 = 15.57; objective P = 0.398), dial test (P = 0.69), or varus stress radiographs (P = 0.98, τ2 = 0.08).

CONCLUSIONS

This study found no statistically significant differences in subjective or objective clinical outcome measurements after fibular-based versus combined TF-based PLC reconstruction. Further prospective evaluation comparing long-term clinical outcomes, complications, and surgical time may help to elucidate a preferred reconstructive technique.

ANATOMICAL STUDY OF THE POSTEROLATERAL LIGAMENT COMPLEX OF THE KNEE: LCL AND POPLITEUS TENDON

Objective:

To analyse the distances between the femoral insertions of the popliteus tendon (PT) and the lateral collateral ligament (LCL) through dissections of cadaveric specimens in a mixed population.

Methods:

Fresh cadavers were dissected, and the anthropometric data of all specimens were recorded. The distances from the origin of the PT to the LCL in the femoral region and the diameter of each structure were measured using a digital calliper.

Results:

In total, 11 unpaired knees were dissected, eight men and three women, with an average age of 71.5 ± 15.2 years, weight of 57.2 ± 15.6 kg, and a mean height of 170.5 ± 8.2 cm. The distance from the center of the femoral footprint of the LCL to the PT was 10.0 ± 2.4 mm. The distances between the edges closest to each other and those more distant from each other were 3.1 ± 1.1 mm and 16.3 ± 2.4 mm, respectively.

Conclusion:

The distance between the midpoints of the PT and the LCL in our mixed population is smaller than the distances often reported in the literature. PLC reconstruction with separate tunnels for the LCL and PT may not be technically possible for individuals of any population.Level of Evidence III, Diagnostic studies.

Posterolateral corner knee injuries: a narrative review

Limited knowledge of the anatomy and biomechanics of the posterolateral corner (PLC) of the knee, coupled with poor patient outcomes with non-operative management, resulted in the PLC often being labelled as the 'dark side' of the knee. In the last two decades, extensive research has resulted in a better understanding of the anatomy and function of the PLC, and has led to the development of anatomic reconstructions that have resulted in improved patient outcomes.Despite considerable attention in the clinical orthopaedic literature (nearly 400 articles published in the last decade), a standardized algorithm for the diagnosis and treatment of the PLC is still lacking, and much controversy remains.Considering the literature review, there is not a reconstruction technique that clearly prevails over the others. As anatomic, biomechanical, and clinical knowledge of PLC injuries continues to progress, finding the balance between re-creating native anatomy and safely performing PLC reconstruction provides a big challenge. Treatment decisions should be made on a case-by-case basis. Cite this article: EFORT Open Rev 2021;6:676-685. DOI: 10.1302/2058-5241.6.200096.

Evidence-Based Clinical Anatomy of the Popliteofibular Ligament and Its Importance in Orthopaedic Surgery: Cadaveric Versus Magnetic Resonance Imaging Meta-analysis and Radiological Study

BACKGROUND

The popliteofibular ligament (PFL) is a static stabilizer of the posterolateral corner of the knee, preventing varus angulation, tibial rotation, and posterior translation. The PFL is anatomically variable, and there is no current review that outlines its prevalence rate and morphological variations.

PURPOSE

To investigate the anatomic prevalence and morphological qualities of the PFL in various global patient populations via a meta-analysis of relevant literature involving both cadaveric dissections and patient-based research using magnetic resonance imaging (MRI) scans.

STUDY DESIGN

Meta-analysis.

METHODS

We pooled literature data detailing PFL prevalence rates and performed a retrospective MRI study of 100 knees to determine the overall PFL prevalence. Data searches and analyses were performed according to Anatomical Quality Assurance and PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines.

RESULTS

There were 30 cadaveric studies and 11 MRI studies (including our radiological investigation), representing a total of 1595 lower limbs. The meta-analysis of cadaveric studies showed a higher prevalence of the PFL than the meta-analysis of MRI studies, with 98.4% (95% CI, 97.5%-99.2%) and 89.0% (95% CI, 73.9%-98.6%), respectively. Our MRI investigation reported a PFL prevalence of 92.0%.

CONCLUSION

The PFL was found to be a constant or rarely absent anatomic structure of the human knee according to the analysis of cadaveric dissection studies, and it was identified notably less on MRI, albeit not significantly. Increasing PFL anatomic knowledge, including awareness of its prevalence and morphological diversity, will improve injury diagnoses, treatment methods, and prognoses.

Fibular Collateral Ligament Reconstruction Graft Options: Clinical and Radiographic Outcomes of Autograft Versus Allograft

PURPOSE

To compare varus knee stability and clinical outcomes between patients who underwent fibular collateral ligament reconstruction (FCLR) or lateral collateral ligament (LCL) reconstruction with autografts versus allografts when undergoing concomitant anterior cruciate ligament reconstruction (ACLR).

METHODS

All patients who underwent primary ACLR and concomitant FCLR from 2010 to 2017 performed by a single surgeon (R.F.L.) were retrospectively identified. Clinical characteristics and graft choices for FCLR were collected. Patients with a minimum 2-year follow-up for clinical outcome scores and 6-month stress radiographs were included. Patients with any other ligamentous procedure or revision ACLR were excluded.

RESULTS

We identified 69 primary ACLR with concomitant FCLR patients who met the inclusion criteria. Fifty patients underwent FCLR with semitendinosus autografts, and 19 with allografts. There were no significant side-to-side differences (SSDs) in lateral compartment gapping on varus stress x-rays between the 2 cohorts (allograft, 0.49 mm; autograft, 0.15 mm, P = .22), and no FCLR failures. There were no significant differences between autograft and allograft groups at minimum 2-year outcomes for 12-Item Short Form mental or physical composite score (SF12 MCS, P = .134; SF12 PCS, P = .642), WOMAC total (P = .158), pain (P = .116), stiffness (P = .061), or activity (P = .252); International Knee Documentation Committee (IKDC) (P = .337), Tegner (P = .601), Lysholm (P = .622), or patient satisfaction (P = .218). There were no significant differences in clinical knee stability between groups at an average follow-up of 3.6 years (P = 1.0).

CONCLUSION

There were no differences in varus stress laxity 6 months postoperatively or clinical outcome scores at ≥2 years postoperatively between patients having FCL reconstructions with either autograft or allograft. This study demonstrates that both hamstring autografts and allografts for FCL reconstructions offer reliable and similar radiographic and clinical results at short-term follow-up.

LEVEL OF EVIDENCE

III, retrospective comparative trial.

Single-Stage Revision Anterior Cruciate Ligament Reconstruction: Experience With 91 Patients (40 Elite Athletes) Using an Algorithm

BACKGROUND

The increased prevalence of anterior cruciate ligament (ACL) reconstruction has led to an increased need for revision ACL reconstructions. Despite the growing body of literature indicating that single-stage revision ACL reconstruction can yield good outcomes, there is a lack of data for determining when and how to safely perform a single-stage revision.

PURPOSE

To assess the outcomes, graft failure rates, and return-to-play rates of a decision-making algorithm for single-stage revision ACL reconstruction.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

We reviewed a consecutive series of revision ACL reconstructions performed by the senior author between September 2009 and July 2016 with minimum 2-year follow-up. All patients were assessed, and decision making was undertaken according to the algorithm. Outcomes measured were further surgery, graft rerupture, re-revision, Tegner score, and Knee injury and Osteoarthritis Outcome Score (KOOS). For the elite athlete population, return-to-play time, duration, and level of play after surgery as compared with preinjury were also determined.

RESULTS

During this period, 93 procedures were performed in 92 patients (40 elite athletes). Two 2-stage procedures were undertaken, leaving 91 single-stage procedures (91 patients) to form the basis for further study. At a mean 4.3 years (SD, 2.2 years) after surgery, there had been 2 re-revisions (2.2%) and 2 further instances of graft failure that had not been re-revised (total graft failure rate, 4.4%). There were 17 subsequent procedures, including 6 arthroscopic partial meniscectomies, 5 removals of prominent implants, and 1 total knee arthroplasty. The mean Tegner score was 8.02 before graft rerupture and 7.1 at follow-up. At follow-up, the mean KOOS outcomes were 79.3 for Symptoms, 88.0 for Pain, 94.2 for Activities of Daily Living, 73.6 for Sport, and 68.9 for Quality of Life. Of 40 elite athletes, 35 returned to play at a mean 11.2 months (SD, 3.6 months) after surgery.

CONCLUSION

Single-stage revision ACL reconstructions can be performed reliably in the majority of patients, with good clinical outcomes, low rerupture rates, and high-return-to play rates, even in the elite athlete population.

The Pathoanatomy of Posterolateral Corner Ligamentous Disruption in Multiligament Knee Injuries Is Predictive of Peroneal Nerve Injury

BACKGROUND

A description of the precise locations of ligamentous and myotendinous injury patterns of acute posterolateral corner (PLC) injuries and their associated osseous and neurovascular injuries is lacking in the literature.

PURPOSE

To characterize the ligamentous and myotendinous injury patterns and zones of injury that occur in acute PLC injuries and determine associated rates of peroneal nerve palsies and vascular injuries, as well as fracture and dislocation.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

We retrospectively identified all patients treated for an acute multiligament knee injury (MLKI) at our level 1 trauma center from 2001 to 2018. From this cohort, all patients with PLC injuries were identified. Demographics, involved ligaments and tendons, neurovascular injury, and presence of fracture and dislocation were compared with the larger multiligament knee cohort. Incidence and location of injury of PLC structures-from proximal to midsubstance and distal injury-were recorded.

RESULTS

A total of 100 knees in 100 patients were identified as having MLKIs. A total of 74 patients (74%) had lateral-sided ligament injuries. Of these, 23 (31%) had a peroneal nerve palsy associated with their injury; 10 (14%), a vascular injury; and 23 (31%), a fracture. Patients with PLC injuries had higher rates of peroneal nerve injury as compared with those having acute MLKIs without a PLC injury (31% vs 4%; P = .005). Patients with a complete peroneal nerve palsy (n = 17) were less likely to regain function than those with a partial peroneal nerve palsy (n = 6; 12% vs 100%; P < .0001). Complete injury to the lateral collateral ligament (LCL) occurred in 71 of 74 (96%) PLC injuries, with 3 distinct patterns of injury demonstrated. Fibular avulsion of the LCL was the most common zone of injury (65%), followed by femoral avulsion (20%) and midsubstance tear (15%). Location of injury to the LCL was associated with the rate of peroneal nerve injury, with midsubstance tears and fibular avulsions associated with higher rates of peroneal nerve injury.

CONCLUSION

MLKIs with involvement of the PLC are more likely to suffer peroneal nerve injury. The LCL is nearly always involved, and its location of injury is predictive of peroneal nerve injury. Patients with a complete peroneal nerve palsy at presentation are much less likely to regain function.

Proximal Tibiofibular Joint: A Forgotten Entity in Multi-Ligament Injuries of the Knee

PURPOSE

The proximal tibiofibular joint (PTJF) can be injured with the structures in the lateral aspect of the knee in a multi-ligament knee injury (MLKI) patient. Such injuries are scarce but require attention in the management of the complex MLKIs. The assessment and management of such injuries are not well described in the English literature. This study describes the frequency of PTFJ injuries, clinical assessment and functional outcomes of such injuries in MLKI patients.

METHODOLOGY

The data were collected retrospectively from the cohort from 2013 to 2018. The 84 MLKI were included in the study, out of which 9 patients had associated PTFJ injury. All the PTFJ injuries were operated by one single surgeon (D.S) which involves stabilization with K-wires (Kirschner wire) and fixation with 4 mm cancellous cannulated screw along with reconstruction surgery for MLKI in single stage.

RESULTS

The frequency of PTFJ injury in our patient cohort is 10.71%. Three patients out of the nine patients received Larson procedure apart from the fixation of PTFJ. At a mean follow-up of 13 months, the Lysholm score was 77.4 (range: 69-86) and mean modified Cincinnati score was 62 (range: 52-72). There was grade I posterior laxity present in one patient with PCL and PLC injury, one patient with ACL, PCL and PLC injury, and one patient with ACL, PCL, MCL and PLC injury at final follow-up. Terminal flexion of 15° or more restriction was noted in six patients. All patients were satisfied with the outcome.

CONCLUSION

Evaluation of PTFJ should be an integral part of preoperative as well as an intraoperative examination of MLKI patients. The fixation of this joint is of utmost importance for the reconstructive ligament procedures on the lateral aspect of the knee. The dial test used for the assessment of the integrity of PLC injury should have a prerequisite of proximal tibiofibular joint stability, otherwise, it can lead to erroneous assessment.

LEVEL OF EVIDENCE

IV.

Concomitant Posterolateral Corner Injuries in Skeletally Immature Patients With Acute Anterior Cruciate Ligament Injuries

BACKGROUND

Missed posterolateral corner (PLC) injuries are a known cause of anterior cruciate ligament reconstruction (ACL) failure in the adult population. Failed ACL reconstruction causes significant morbidity in the skeletally immature pediatric population. There is little literature on the character and potential significance of PLC injuries in skeletally immature patients.

METHODS

Magnetic resonance imaging studies of the knee at a tertiary care children's hospital for patients who underwent an ACL reconstruction without PLC surgery were retrospectively reviewed. Demographic variables were obtained through chart review, and magnetic resonance imaging studies were evaluated for PLC (popliteus, fibular collateral ligament, popliteofibular ligament, and arcuate ligament) injury, and ACL, medial collateral ligament (MCL), bone bruise, fracture, and meniscal pathology by an experienced pediatric musculoskeletal radiologist.

RESULTS

A total of 50 patients with a mean age at 13.3 years at injury were analyzed. PLC injuries were found in 26 patients (52%), with 7 patients (14%) having a complete tear of a component of the PLC. There was no association between sex (P=0.35), Segond fracture (P=0.09), meniscus injury (P=0.92), or MCL injury (P=0.24) with the risk of PLC injury. There was an association between patient age and PLC injury (P=0.02). For each additional year of age, the odds of PLC injury increased by 1.8 times (odds ratio, 1.8; 95% confidence interval, 1.4-2.2). There was no association between PLC injury and ACL graft failure (P=0.19).

CONCLUSIONS

Missed PLC injuries are a significant source of morbidity and poor clinical outcomes in the management of concomitant ACL injuries in adults. This study demonstrates the prevalence of PLC injuries in the setting of concomitant ACL injuries in the unique skeletally immature patient population. Incomplete PLC injuries are relatively common. Complete PLC injuries are relatively uncommon. PLC injury was more common in older patients. No other concomitant injury predicted the likelihood of PLC injury. Further research is needed regarding the risk of ACL reconstruction failure from associated PLC injury and the indications for PLC reconstruction in skeletally immature patients.

LEVEL OF EVIDENCE

Level IV-diagnostic study.