Anatomy and Biomechanics of the Lateral Side of the Knee and Surgical Implications

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.

The effect of different mechanism combinations on sliding between brace and lower limb during walking and leg-raising

Knee braces are commonly used to support the knee joint and improve function. However, brace sliding caused by the misalignment between brace and knee during motion is a common problem, which reduces the therapeutic effect and leads to brace abandonment. To investigate the effect of mechanism combinations on sliding, an experimental brace was designed to isolate the mechanism as the sole variable. Ten healthy participants were recruited, each of whom worn four combinations of lateral/medial mechanisms: lateral and medial single-axis (SA), lateral super gear (SG) and medial non-circular gear (NCG), lateral four-bar linkage (FL) and medial SG, and lateral FL and medial NCG. The knee flexion angle was collected using inertial measurement units, and brace sliding was measured by 3D motion capture system. All combinations had significant changes in peak sliding of thigh and shank compared to the SA combination (p < 0.05), but lateral FL and medial NCG combination had the lowest peak and final sliding during walking and leg-raising, with significant reductions of 40.7 and 85.3% in peak sliding of thigh, and significant reductions of 56.3 and 72.0% in peak sliding of shank, respectively (p < 0.05). Moreover, the mechanism combination did not significantly impact the knee range of motion (p > 0.05). The mechanism combination that fit the instantaneous center of rotation of lateral/medial condyle of knee joint demonstrates a significant reduction in brace sliding. Additionally, the peak sliding during motion is significantly higher than the final sliding.

A Novel Fixation Method of the Graft to the Fibular Head in Knee Lateral Collateral Ligament Reconstruction: Technical Note

The lateral collateral ligament (LCL) is the strongest lateral stabilizer of the knee. It provides support against varus stress and posterolateral rotation of the knee. Lateral collateral ligament injuries mostly occur together with anterior and/or posterior cruciate ligament injuries. While grades 1 and 2 injuries are treated conservatively since they are partial injuries, total ruptures, as in grade 3, require surgical treatment. In conventional LCL reconstruction methods, hamstring grafts are used, and bioscrews are used in bone-tendon fixation. Lateral collateral ligament reconstruction is usually performed as a component of multiple ligament surgery. Therefore, there is a need for a contralateral hamstring tendon or allograft. The present article aims to define a technique that does not require tendon grafts and bioscrews in fibular fixation.

Effect of lower limb alignment on outcome after lateral unicompartmental knee arthroplasty: a retrospective study

PURPOSE

The objective of this study was to investigate the correlation between lower limb alignment and patient outcomes after lateral unicompartmental knee arthroplasty (LUKA).

METHODS

In this retrospective study, the information of 51 patients who underwent lateral UKA was collected after an average of 27months of follow-up (13 to 60 months). Evaluation indicators include the AKS and WOMAC score. The Kellgren-Lawrence grade is used to evaluate the severity of osteoarthritis, while the hip-knee-ankle (HKA) angle is utilized to measure the valgus angle of lower limb alignment.

RESULT

Patients with postoperative valgus (≥ 3°) alignment had the best outcomes, while those with varus (≤-3°) alignment had the worst outcomes (p < 0.001). Furthermore, it was noted that patients with preoperative mild valgus (≤ 4°) alignment had worse postoperative outcomes than those with severe valgus (≥ 7°) alignment (p < 0.05). The study also revealed a positive correlation between postoperative valgus and WOMAC scores (p < 0.001), whereas a negative correlation was observed between the change in valgus angle and WOMAC scores (p = 0.005).

CONCLUSION

During follow-ups, we found that lower limb alignment seems to be an independent predictor of postoperative outcomes. It is recommended that more than 3° of valgus alignment should be maintained after LUKA. Surgeons performing lateral UKA should be cautious of overcorrecting alignment, particularly in patients with preoperative mild valgus alignment.

Personalized statistical modeling of soft tissue structures in the knee

Background and Objective: As in vivo measurements of knee joint contact forces remain challenging, computational musculoskeletal modeling has been popularized as an encouraging solution for non-invasive estimation of joint mechanical loading. Computational musculoskeletal modeling typically relies on laborious manual segmentation as it requires reliable osseous and soft tissue geometry. To improve on feasibility and accuracy of patient-specific geometry predictions, a generic computational approach that can easily be scaled, morphed and fitted to patient-specific knee joint anatomy is presented.

Methods: A personalized prediction algorithm was established to derive soft tissue geometry of the knee, originating solely from skeletal anatomy. Based on a MRI dataset (n = 53), manual identification of soft-tissue anatomy and landmarks served as input for our model by use of geometric morphometrics. Topographic distance maps were generated for cartilage thickness predictions. Meniscal modeling relied on wrapping a triangular geometry with varying height and width from the anterior to the posterior root. Elastic mesh wrapping was applied for ligamentous and patellar tendon path modeling. Leave-one-out validation experiments were conducted for accuracy assessment.

Results: The Root Mean Square Error (RMSE) for the cartilage layers of the medial tibial plateau, the lateral tibial plateau, the femur and the patella equaled respectively 0.32 mm (range 0.14–0.48), 0.35 mm (range 0.16–0.53), 0.39 mm (range 0.15–0.80) and 0.75 mm (range 0.16–1.11). Similarly, the RMSE equaled respectively 1.16 mm (range 0.99–1.59), 0.91 mm (0.75–1.33), 2.93 mm (range 1.85–4.66) and 2.04 mm (1.88–3.29), calculated over the course of the anterior cruciate ligament, posterior cruciate ligament, the medial and the lateral meniscus.

Conclusion: A methodological workflow is presented for patient-specific, morphological knee joint modeling that avoids laborious segmentation. By allowing to accurately predict personalized geometry this method has the potential for generating large (virtual) sample sizes applicable for biomechanical research and improving personalized, computer-assisted medicine.

Popliteus Avulsion Fracture After Unicompartmental Arthroplasty: A Case Report

CASE

An active 64-year-old patient presented with new-onset lateral knee pain 42 days after an uncomplicated medial unicompartmental knee arthroplasty (UKA). Magnetic resonance imaging and diagnostic injection of local anesthetic identified an avulsion fracture of the popliteus tendon as the source of discomfort. Repair of the tendon to its native footprint was performed with suture anchor fixation. The patient was pain-free and returned to work without restrictions at 12 weeks.

CONCLUSION

We identify a unique cause of knee pain after UKA-avulsion of the popliteus tendon. Successful management of this condition included anatomic repair of the tendon with suture anchor fixation.

Minimally Invasive Knee Lateral Collateral Ligament Reconstruction Using Partial Biceps Femoris Tendon Autograft

Lateral collateral ligament (LCL) is known as an important ligament to restrain varus force of the knee, especially in 30° knee flexion. From the anatomical study, the insertion of LCL at proximal fibula is intimately close to the insertion of biceps femoris (BF) tendon. Since LCL is infrequently injured in isolation, and with limitation in availability of autograft and allograft, this study proposes the partial anterior BF tendon as an alternative autograft source to reconstruct the LCL. This could be performed either by minimally invasive procedure or standard open technique. The core concept is to preserve the posterior part of the BF tendon to protect the peroneal nerve, by which exploration of this nerve and the proximal fibula prior to LCL reconstruction could be exempted. Minimally invasive LCL reconstruction using this autograft would essentially reduce soft tissue injury, shorten the operative time, and enhance recovery of the reconstructed knee.

Functional knee apparatus for the evaluation of ligamentous tensions on contact loads

BACKGROUND

Soft tissue balancing is integral in providing stability following total knee arthroplasty (TKA). Although intraoperative contact load sensors are providing insights into the effects of soft tissue balancing, there is still a lack of understanding of the relationship between the knee's ligamentous tensions and joint surface contact loads. This study reports on the development of a multifunctional testing apparatus that can quantify the effects of ligamentous tension on joint contact loads in a controlled repeatable environment.

METHODS

The functional knee apparatus was constructed to act as an anatomical substitute for the benchtop assessment of intraoperative soft tissue balancing. The system was calibrated through reproduction of results from a cadaveric study that employed intraoperative load sensors. Experimentation was then conducted to quantify the effects of tensile pretension variation on measured contact loads throughout the full range of flexion.

RESULTS

A linear relationship between the ligamentous tensions and contact loads was observed, with ligaments contributing to 74-80% of the measured contact loads. Ligamentous tensions could be approximated from measured contact loads to within ± 23 N.

CONCLUSION

The proposed apparatus can prove to be a valuable tool in the continued exploration of currently undocumented effects (e.g. surgical alteration) in soft tissue balancing. In addition to quantifying the relationship between ligamentous tensions and joint contact loads, soft tissue loading conditions where bicondylar contact was lost (i.e. known sign of kinematic instability) were identified. As a corollary, this system may be able to provide insights on soft tissue balancing standards predictive of patient outcomes.

Percutaneous Lateral Collateral Ligament Release for Arthroscopic Procedures of the Knee: The "Lateral Pie-Crusting"

Arthroscopy of the knee is among the most frequent procedures worldwide in orthopaedic surgery. To avoid iatrogenic cartilage injury, adequate visualization and working space are mandatory to perform complex procedures. Narrow femorotibial joint space is often encountered, and it is challenging to obtain consistent satisfactory results. Medial collateral ligament release is safe and reliable for facilitating medial joint widening. Current clinical studies support lateral collateral ligament (LCL) healing capacity in isolated injuries. This article describes a simple, safe, and reproducible technique of LCL release through a multiple-puncture method to facilitate lateral compartment visualization and instrumentation, the so-called lateral pie-crusting.

An all-arthroscopic surgery technique for snapping popliteal tendon syndrome: A case report and literature review

RATIONALE

The incidence of snapping popliteus tendon syndrome, a type of lateral knee snapping, is not high, so making an accurate diagnosis is difficult. A proper treatment following an accurate diagnosis is essential for improvement. Very few cases have been reported of its treatment.

PATIENT CONCERNS

An 18-year-old male patient had experienced painful popping in the lateral part of the knee during knee flexion for 3 years before his hospital visit.

DIAGNOSES

Snapping popliteus tendon syndrome.

INTERVENTIONS

The patient underwent an all-arthroscopic surgery. Tendon debulking and tissue debridement around the popliteus tendon was conducted, but the snapping did not resolve. The enlarged tubercle was excised through an arthroscopic procedure using a burr, and the surgery was finished after confirming that snapping was resolved.

OUTCOMES

Full range of motion (ROM) was recovered 6 weeks after surgery and the snapping did not recur.

LESSONS

Snapping popliteus tendon syndrome is a disease that is hardly recognized due to its low prevalence and difficulty in diagnosis, and it requires close observation of the patient before surgery. The location of the tenderness and the snapping occurrence must also be carefully identified. Our procedure is an entirely arthroscopic technique; as it has the prominent advantage of a speedy recovery and easy rehabilitation, it could also be helpful to set treatment standards for this disease in the future.

Lateral unicompartmental knee arthroplasty (UKA) showed a lower risk of failure compared to medial unicompartmental knee arthroplasty in the Register of Prosthetic Orthopedic Implants (RIPO)

INTRODUCTION

The present study aimed to investigate differences in survivorship between medial and lateral unicompartmental knee arthroplasty (UKA) by analyzing the data of an Italian regional registry. The hypothesis was that, according to recent literature, lateral implants have comparable survivorship with regard to the medial implants.

MATERIALS AND METHODS

The Register of Orthopaedic Prosthetic Implants (RIPO) of Emilia-Romagna (Italy) database was searched for all UKAs between July 1, 2000, and December 31, 2019. For both cohorts, subject demographics and reasons for revision were presented as a percentage of the total cohort. Kaplan-Meier survivorship analysis was performed using revision of any component as the endpoint and survival times of unrevised UKAs taken as the last observation date (December 31, 2019, or date of death).

RESULTS

Patients living outside the region and symmetrical implants (which do not allow the compartment operated to be traced) were excluded. 5571 UKAs implanted on 5172 patients (5215 medial UKAs and 356 lateral UKAs) were included in the study. The survivorship analysis revealed 13 failures out of 356 lateral UKAs (3.7%) at a mean follow-up of 6.3 years and 495 failures out of 5215 medial UKAs (9.5%) at a mean follow-up of 6.7 years. The medial UKAs had a significantly higher risk of failure, with a Hazard Ratio of 2.6 (CI 95% 1.6-4.8; p < 0.001), adjusted for age, gender, weight, and mobility of the insert. Both the groups revealed a good survival rate, with 95.2% of lateral implants and 87.5% of medial implants still in situ at 10 years of follow-up.

CONCLUSIONS

Lateral UKA is a safe procedure showing longer survivorship than medial UKAs (95.2% and 87.5% at 10 years, respectively) in the present study.

LEVEL OF EVIDENCE

Level 3, therapeutic study.

Varus stress MRI in the refined assessment of the posterolateral corner of the knee joint

Magnetic resonance imaging (MRI) is commonly used to assess traumatic and non-traumatic conditions of the knee. Due to its complex and variable anatomy, the posterolateral corner (PLC)—often referred to as the joint’s dark side—remains diagnostically challenging. We aimed to render the diagnostic evaluation of the PLC more functional by combining MRI, varus loading, and image post-processing in a model of graded PLC injury that used sequential transections of the lateral collateral ligament, popliteus tendon, popliteofibular ligament, and anterior cruciate ligament. Ten human cadaveric knee joint specimens underwent imaging in each condition as above, and both unloaded and loaded using an MR-compatible device that standardized loading (of 147 N) and position (at 30° flexion). Following manual segmentation, 3D joint models were used to computationally measure lateral joint space opening for each specimen, configuration, and condition, while manual measurements provided the reference standard. With more extensive ligament deficiency and loading, lateral joint spaces increased significantly. In conclusion, varus stress MRI allows comprehensive PLC evaluation concerning structural integrity and associated functional capacity. Beyond providing normative values of lateral compartment opening, this study has potential implications for diagnostic and surgical decision-making and treatment monitoring in PLC injuries.

Does Implant Design Influence Failure Rate of Lateral Unicompartmental Knee Arthroplasty? A Meta-Analysis

BACKGROUND

Lateral unicompartmental knee arthroplasty (UKA) is a viable solution for isolated lateral compartment arthritis. Several prosthetic designs are available such as fixed-bearing metal-backed (FB M-B), fixed-bearing all-polyethylene (FB A-P), and mobile-bearing metal-backed (MB M-B) implants. The purpose of this meta-analysis is to compare failure rates of different prosthetic designs.

METHODS

Preferred Reporting Items for Systematic Reviews and Meta-Analyses systematic review was conducted using 4 databases (MEDLINE, EMBASE, Cochrane, and PubMed) to identify all studies that investigate outcomes of lateral UKA. Twenty-one studies met the inclusion criteria, and failure rates were compared by implant type and follow-up time separately in order to assess potential confounding factors. Two separate analyses have been performed among different implant designs (FB M-B vs FB A-P vs MB M-B) and different follow-ups (<5 years, between 5 and 10 years, >10 years).

RESULTS

The failure rate of FB M-B lateral UKA was significantly lower compared to other lateral UKA designs present in the market (0.8% vs 8.6% and 7.1% for FB M-B, FB A-P, and MB M-B, respectively). No significative difference among groups has been detected when comparing all implants with regard to follow-up time.

CONCLUSION

Considering actual evidence, for a surgeon approaching lateral UKA, the FB M-B design is preferable, given the lower failure rates and subsequently a longer implant survivorship.

Arthroscopic Treatment of Popliteus Tendinitis Using the Accessory Portal

Introduction

This study aimed to evaluate the effect of arthroscopic treatment of popliteus tendinitis via an auxiliary extreme lateral approach and to investigate the pathogenesis and treatment of popliteus tendinitis.

Materials and Methods

From 2016 to 2020, arthroscopic popliteus tendon ablation was performed in 15 patients (15 knees) with popliteus tendinitis via an auxiliary extreme lateral approach. Clinical outcomes were assessed using the Lysholm knee scoring scale, the Tegner score, the International Knee Documentation Committee (IKDC) score and the visual analogue scale (VAS) pain score at the 24-month follow-up after surgery.

Results

A total of 15 patients (mean age, 51.1 ± 7.1 years) were included. They had a mean body mass index of 23.8 ± 2.1 kg/m². The minimum follow-up period was 24 months. Comparing the postoperative state to the preoperative state, the mean postoperative Lysholm score, Tegner score, and IKDC score improved significantly from 70.0 ± 5.0, 3.0 ± 0.9, and 62.3 ± 5.5 to 89.3 ± 4.2, 4.6 ± 0.61, and 80.5 ± 4.4, respectively (p < 0.01). The preoperative VAS score for pain improved from 6.4 ± 0.5 to 0.9 ± 0.4 (p < 0.01). No patients were lost to follow-up.

Conclusions

Following arthroscopic-assisted treatment, all the patients with popliteus tendinitis achieved satisfactory clinical outcomes in terms of pain relief and improved function.

Level of Evidence

Level IV

Isolated Femoral LCL Avulsion Fracture in the Adult Knee: Two Patient Cases and Literature Review

Avulsion injuries of the LCL most commonly occur at the fibular insertion. Femoral LCL avulsion injuries have only been previously described in pediatric patients or as multiligament knee injury components among adults. This case series with comprehensive literature review describes for the first time 2 cases of isolated LCL femoral avulsion fractures in adults including conservative treatment outcomes. Both patients sustained a strong varus stress mechanism to their right knee, following sport injury or road traffic accident. For both patients, a complete radiographic evaluation including X-rays, MRI, and CT scan confirmed no other associated knee lesions. The femoral LCL avulsion fractures that were observed were minimally displaced and noncomminuted. Furthermore, imagery suggested preserved integrity at the superior lateral genicular artery, adjacent articular capsule, and IT band. Based on clinical and imaging evaluations, the decision was made to follow conservative treatment. By 10 weeks postinjury, both patients were asymptomatic with early radiological fracture healing evidence. Comparative varus stress radiographs at 20° knee flexion revealed no side-to-side differences and clinical exam showed no posterolateral rotatory instability. The second patient case presented with mild femoral LCL attachment calcification on follow-up CT-scan. Following a detailed analysis of anatomic injury characteristics, we suggest that patients with isolated femoral LCL avulsion fractures have low secondary displacement risk provided SLGA, articular capsule, and IT band integrity are present. In contrast to high-grade ligamentous and distal avulsion LCL injuries, we recommend conservative treatment for patients who sustain these lesions.

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.

Anatomy, magnetic resonance and arthroscopy of the popliteal hiatus of the knee: normal aspect and pathological conditions

The popliteal hiatus is a complex region, formed by the confluence of various structures connecting the meniscus, popliteal tendon, tibia and fibula.The main structures that can be found are the three popliteomeniscal fascicles (anterior, postero-inferior and postero-superior), the lateral and posterior meniscotibial ligaments, the popliteofibular ligament and the meniscofibular fascicle.These structures can be identified in most cases using magnetic resonance imaging, and their 'static' assessment can be performed.Arthroscopic assessment is useful in identifying and testing 'dynamically' the integrity of the structures around the popliteal hiatus.Injuries or abnormalities of the popliteal hiatus and its structures could result in meniscal hypermobility and subluxation; however, these injuries are often unrecognized.Possible abnormalities in this region, apart from the well-known bucket-handle meniscal tear, are the Wrisberg Type III discoid meniscus, and meniscal fascicles tears. Cite this article: EFORT Open Rev 2021;6:61-74. DOI: 10.1302/2058-5241.6.200089.

Knee Ligament Anatomy and Biomechanics

An understanding of knee ligament anatomy and biomechanics is foundational for physicians treating knee injuries, especially the more rare and morbid multiligamentous knee injuries. This chapter examines the roles that the cruciate and collateral anatomy and morphology play in their kinematics. Additionally, the biomechanics of the ACL, PCL, MCL, and LCL are discussed as they have surgical and reconstructive implications.

The Role of the Posterolateral Tibial Slope in the Rotational Instability of the Knee in Patients Affected by a Complete Isolated Anterior Cruciate Ligament Injury: Its Value in the Decision-Making Process during the Anterolateral Ligament Reconstruction

Purpose  The aim of this retrospective, multicenter study was to investigate the correlation between a high degree of rotatory instability, posterolateral tibial slope (PLTS), and anterolateral ligament (ALL) injury. Methods  The study population consisted of 76 adults with isolated, complete noncontact anterior cruciate ligament (ACL) tear. The sample was divided into two groups according to the preoperative degree of rotator instability (group A: pivot-shift test grades 2 and 3; group B: pivot-shift test grade 1). Preoperative magnetic resonance imaging (MRI) assessment included angle of PLTS, posterior shift of the lateral femoral condyle (16 mm) on the tibial plateau, and the presence/absence of ALL injury. The two groups were compared for differences. Results  There was a statistically significant association between pivot-shift test grades 2 and 3 (group A), PLTS slope angle > 9 degrees, and ALL injury ( p  < 0.05). Group A also demonstrated a greater posterior shift of lateral femoral condyle (>11 mm), which was, however, not statistically significant when evaluated as an isolated variable. Conclusion  Our study indicates that an increased PLTS is associated with an increased incidence of ALL injury and an increased grade of pivot shift in patients with ACL tear. Assessment of posterolateral tibial slope on MRI can therefore play a key adjunct role in the surgical planning of ALL reconstruction, especially in cases when ALL damage is radiologically difficult to detect or doubtful. Level of Evidence  This is a retrospective comparative level III study.

Editorial Commentary: Shedding Light on the Posterolateral Corner of the Knee: Can We Do it With the Scope? Is There a Real Benefit?

Historically described as the "dark side of the knee," the posterolateral corner of the knee has been a significant focus of anatomic, biomechanical, and clinical outcomes research due to poor treatment outcomes for these injuries before improvements over the past 2 decades. These research efforts have resulted in significant improvements in the understanding, diagnosis, and surgical treatment of these injuries. Perhaps most importantly, improved understanding of the anatomy and biomechanics has led to the development of anatomic-based reconstructions, which have been subsequently validated with both biomechanical and clinical outcomes. Due to the complex anatomy and proximity of neurovascular structures, reconstructions have historically used large "hockey stick" incisions to provide adequate visualization to identify the anatomic insertions of the static stabilizers and ensure adequate protection of neurovascular structures. These anatomic-based techniques have significantly improved the clinical and objective outcomes of the surgical treatment of posterolateral knee injuries. However, as techniques have evolved and the clinical outcomes have improved, clinicians have attempted to develop and employ less-invasive and arthroscopically assisted techniques. Specifically, given the steep learning curve, paucity of clinical outcomes, increased operative time, and the limited view of the anatomy, which may increase the risk of nonanatomic tunnel placement, and injuries to surrounding structures, we cannot support an arthroscopic approach at this time.

Muscular architecture of the popliteus muscle and the basic science implications

BACKGROUND

The function of the popliteus muscle is largely treated as a static stabilizer and has a lack of basic muscular architectural data to enable study of its dynamic function. A large volume of literature supports its static function and the essential need for reconstruction in the posterolateral knee when injured to restore knee stability.

HYPOTHESIS/PURPOSE

We hypothesize that the popliteus muscle is more significant as a dynamic presence in the knee.

METHODS

A collection of popliteus architectural data was collected from 28 cadaver specimens (mean (SD) 76 years (11)). Physiological cross-sectional area of the popliteus and semimembranosus muscles were calculated from muscle volume and fiber length to power future muscle force prediction models. Posterior knee muscle trajectories were measured with respect to the longitudinal axis of the tibia. A 2-tailed T test was performed.

RESULTS

Significant differences between males and females were found for both the popliteus (p = 1.1E-05) and semimembranosus (p = 2.0E-05) muscle volumes. Significant differences between males and females were also found in PCSA for the popliteus (p = 0.005) and semimembranosus (p = 4.1E-05) muscles. There were no significant differences in fiber length, overall muscle length (with tendon removed), age, and orientation.

CONCLUSION

Further consideration should be given to include the popliteus muscle as a dynamic entity in the knee given its mechanical properties, trajectory, and prior biomechanical evidence showing when and how it is activated. The present study provides data that may shape future directions of research and treatment with regard to posterolateral corner injuries and ligamentous balancing of the knee.

ACL and Posterolateral Corner Injuries

PURPOSE OF REVIEW

The importance of the posterolateral corner (PLC) with respect to knee stability, particularly in the setting of anterior cruciate ligament (ACL) deficiency, has become more apparent in recent years. The purposes of this article are to review the current concepts of PLC injuries and to address their role in the ACL-deficient and ACL-reconstructed knee.

RECENT FINDINGS

Recent literature demonstrates that a single staged, combined reconstruction is optimal. Studies further provide more thorough insight into avoidance of tunnel collision during the multiligament reconstruction. In total, reconstruction procedures have demonstrated successful outcomes in over 90% of patients. In summary, we report that in the setting of suspected concomitant PLC and ACL injury, it is essential to address both injuries; appreciating the local anatomy, diagnostic modalities, and surgical techniques are each crucial to achieving desirable clinical outcomes.

Poorer dynamic postural stability in patients with anterior cruciate ligament rupture combined with lateral meniscus tear than in those with medial meniscus tear

Background

Only limited data are available regarding postural stability between anterior cruciate ligament (ACL)-injured patients with medial meniscus (MM) tear and those with lateral meniscus (LM) tear. The purpose of this study was to compare preoperative postural stability for both involved and uninvolved knees in ACL rupture combined with MM and LM tears. It was hypothesized that there would be a significant difference in postural stability between these two groups.

Methods

Ninety-three ACL-injured patients (53 combined with MM tears vs. 40 combined with LM tears) were included. Static and dynamic postural stability were evaluated with the overall stability index (OSI), anterior–posterior stability index (APSI), and medial–lateral stability index (MLSI) using stabilometry. Knee muscle strength was evaluated using an isokinetic testing device.

Results

In the static postural stability test, none of the stability indices showed significant differences between the two groups for both knees (p > 0.05). In the dynamic postural stability test for involved side knees, the OSI and APSI were significantly higher in the LM tear group compared to the MM tear group (OSI: 2.0 ± 0.8 vs. 1.6 ± 0.5, p = 0.001; APSI: 1.5 ± 0.6 vs. 1.3 ± 0.5, p = 0.023), but not the MLSI (p > 0.05). In the static and dynamic postural stability tests in each group, there were no significant differences between the involved and uninvolved side knees (p > 0.05). There was no significant difference in the knee muscle strength between the two groups (p > 0.05). All postural stability showed no significant correlation with knee muscle strength (p > 0.05).

Conclusion

Dynamic postural stability was poorer in patients with ACL rupture combined with LM tear than in those with MM tear. Therefore, close monitoring for postural stability would be necessary during preoperative and postoperative rehabilitation, especially for patients with ACL rupture combined with LM tear.

Level of evidence: Level III

An Acute Osteochondral Defect Secondary to Fabella Impaction: A Case Report

CASE

A healthy 37-year-old man sustained a knee injury after performing a deep flexion maneuver while skiing and noted immediate knee pain and swelling. Because of persistent inability to fully extend his knee and persistent posterolateral knee pain, he was evaluated and noted to have an acute osteochondral defect of the posterolateral femoral condyle directly adjacent to his fabella. After a trial of nonoperative interventions, he elected to undergo an arthroscopic-assisted open excision of the fabella and a chondroplasty of the posterolateral femoral condyle defect.

CONCLUSION

A traumatic osteochondral defect secondary to a lateral fabella impaction is a rare pathology but must be evaluated in patients performing deep flexion maneuvers who have persistent knee pain and mechanical symptoms. When there is a focal defect with increased edema of both the fabella and posterolateral femoral condyle, an arthroscopic chondroplasty and fabella excision is a valid treatment to return the patient back to desired activities.

Arthroscopic-assisted anatomical reconstruction of the posterolateral corner of the knee joint

Several surgical techniques have been suggested to anatomically reconstruct the posterolateral corner of the knee joint. However, most of them are open techniques that require dissection of the skin and soft tissues without utilizing the advantages of arthroscopic-assisted techniques. Therefore, this study aimed to describe a novel arthroscopic technique that anatomically reconstructs the posterolateral corner of the knee joint. This novel arthroscopic technique can properly identify important landmarks for reconstruction and anatomically reconstruct the three key components (lateral collateral ligament, popliteus tendon, and popliteofibular ligament) of the posterolateral corner of the knee joint.

Identification of Normal and Injured Anterolateral Ligaments of the Knee: A Systematic Review of Magnetic Resonance Imaging Studies

PURPOSE

To identify the normal and injured magnetic resonance imaging appearance of the anterolateral ligament (ALL).

METHODS

A systematic review was performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The PubMed and Cochrane Library electronic databases were used to search for studies that reported the imaging outcomes of the appearance of the ALL. Two authors performed the searches in duplicate up to April 30, 2018, and interobserver agreement was calculated. The methodologic quality of included articles was assessed using an adaptation of the Arrivé methodologic quality scale for clinical studies of radiologic examinations.

RESULTS

From the original 270 records, a total of 24 studies (κ = 0.94) comprising 2,427 knees in 2,388 patients (mean age, 33.3 years; 66% male patients; 63% with anterior cruciate ligament [ACL] injury) were included. The ALL appeared in 51% to 100% of all assessed knees (71%-100% in ACL-injured knees and 64%-97% in uninjured knees) and was injured in 11% to 79% of ACL-injured knees. Reliability rates varied considerably (0.04-1.0 for intraobserver and 0.143-1.0 for interobserver agreement), and the entire portion of the ligament was often not seen. The tibial insertion was seen in 21% to 96% of cases, followed by the meniscal (range, 0%-100%) and femoral (range, 0%-90%) insertions. The mean methodologic quality score was 5.1 ± 1.8 out of a possible score of 9.

CONCLUSIONS

High variability was found in the identification of normal and injured ALL definition methods and the respective magnetic resonance imaging findings. Reliability rates varied considerably, and the entire portion of the ligament was often not seen.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II to IV studies.

Anatomic Posterolateral Corner Reconstruction Using Single Graft Plus Adjustable-Loop Suspensory Fixation Device

The original description of the LaPrade technique for anatomic posterolateral corner reconstruction addresses the 3 main stabilizing structures: the fibular collateral ligament, the popliteus, and the popliteofibular ligament. The use of two separate grafts (originally described with a tendo-Achilles allograft) may restrict the utility of the technique when sources of allograft may be limited and autografts must be used, particularly in the context of multiligament reconstruction. We present a modification of the technique, in which an adjustable cortical button is used for tibial fixation, which allows for the use of a single graft while maintaining the ability to independently tension the popliteus, popliteofibular ligament, and fibular collateral ligament limbs of the graft.

Risk Factors for Knee Injury in Golf: A Systematic Review

Background

Golf is commonly considered a low-impact sport that carries little risk of injury to the knee and is generally allowed following total knee arthroplasty (TKA). Kinematic and kinetic studies of the golf swing have reported results relevant to the knee, but consensus as to the loads experienced during a swing and how the biomechanics of an individual’s technique may expose the knee to risk of injury is lacking.

Objectives

Our objective was to establish (1) the prevalence of knee injury resulting from participation in golf and (2) the risk factors for knee injury from a biomechanical perspective, based on an improved understanding of the internal loading conditions and kinematics that occur in the knee from the time of addressing the ball to the end of the follow-through.

Methods

A systematic literature search was conducted to determine the injury rate, kinematic patterns, loading, and muscle activity of the knee during golf.

Results

A knee injury prevalence of 3–18% was established among both professional and amateur players, with no clear dependence on skill level or sex; however, older players appear at greater risk of injury. Studies reporting kinematics indicate that the lead knee is exposed to a complex series of motions involving rapid extension and large magnitudes of tibial internal rotation, conditions that may pose risks to the structures of a natural knee or TKA. To date, the loads experienced by the lead knee during a golf swing have been reported inconsistently in the literature. Compressive loads ranging from 100 to 440% bodyweight have been calculated and measured using methods including inverse dynamics analysis and instrumented knee implants. Additionally, the magnitude of loading appears to be independent of the club used.

Conclusions

This review is the first to highlight the lack of consensus regarding knee loading during the golf swing and the associated risks of injury. Results from the literature suggest the lead knee is subject to a higher magnitude of stress and more demanding motions than the trail knee. Therefore, recommendations regarding return to golf following knee injury or surgical intervention should carefully consider the laterality of the injury.

Electronic supplementary material

The online version of this article (doi:10.1007/s40279-017-0780-5) contains supplementary material, which is available to authorized users.

Influence of the Anterolateral Ligament on Knee Laxity: A Biomechanical Cadaveric Study Measuring Knee Kinematics in 6 Degrees of Freedom Using Dynamic Radiostereometric Analysis

Background:

An anterior cruciate ligament (ACL) rupture often occurs during rotational trauma to the knee and may be associated with damage to extracapsular knee rotation–stabilizing structures such as the anterolateral ligament (ALL).

Purpose:

To investigate ex vivo knee laxity in 6 degrees of freedom with and without ALL reconstruction as a supplement to ACL reconstruction.

Study Design:

Controlled laboratory study.

Methods:

Cadaveric knees (N = 8) were analyzed using dynamic radiostereometry during a controlled pivotlike dynamic movement simulated by motorized knee flexion (0° to 60°) with 4-N·m internal rotation torque. We tested the cadaveric specimens in 5 successive ligament situations: intact, ACL lesion, ACL + ALL lesion, ACL reconstruction, and ACL + ALL reconstruction. Anatomic single-bundle reconstruction methods were used for both the ACL and the ALL, with a bone-tendon quadriceps autograft and gracilis tendon autograft, respectively. Three-dimensional kinematics and articular surface interactions were used to determine knee laxity.

Results:

For the entire knee flexion motion, an ACL + ALL lesion increased the mean knee laxity (P < .005) for internal rotation (2.54°), anterior translation (1.68 mm), and varus rotation (0.53°). Augmented ALL reconstruction reduced knee laxity for anterior translation (P = .003) and varus rotation (P = .047) compared with ACL + ALL–deficient knees. Knees with ACL + ALL lesions had more internal rotation (P < .001) and anterior translation (P < .045) at knee flexion angles below 40° and 30°, respectively, compared with healthy knees. Combined ACL + ALL reconstruction did not completely restore native kinematics/laxity at flexion angles below 10° for anterior translation and below 20° for internal rotation (P < .035). ACL + ALL reconstruction was not found to overconstrain the knee joint.

Conclusion:

Augmented ALL reconstruction with ACL reconstruction in a cadaveric setting reduces internal rotation, varus rotation, and anterior translation knee laxity similar to knee kinematics with intact ligaments, except at knee flexion angles between 0° and 20°.

Clinical Relevance:

Patients with ACL injuries can potentially achieve better results with augmented ALL reconstruction along with ACL reconstruction than with stand-alone ACL reconstruction. Furthermore, dynamic radiostereometry provides the opportunity to examine clinical patients and compare the recontructed knee with the contralateral knee in 6 degrees of freedom.

Associated Anterior Cruciate Ligament and Fibular Collateral Ligament Reconstruction With Single Femoral Tunnel and Asymmetric Hamstring Tendon Graft

A technique for associated anterior cruciate ligament and fibular collateral ligament reconstruction is shown, using a single hamstring tendon graft, which is prepared asymmetrically, leaving one-third of the length with a single diameter and two-thirds with a double diameter. A single femoral tunnel is created, using an interference screw for fixation and isolation of the grafts. A suspension device is used for tibial fixation, allowing for length adjustment according to the graft's length. The objective of this Technical Note is to provide the orthopaedic surgeon with a resource for anterior cruciate ligament and fibular collateral ligament reconstruction even with short grafts, saving bone stock and avoiding the need for allografts.

A case report of anterior cruciate ligament and posterolateral corner reconstruction using tendon graft preserved in situ

INTRODUCTION

Combined anterior cruciate ligament (ACL) and posterolateral corner (PLC) reconstruction are a rare clinical entity in orthopedic literature, whose management requires different types of tendon grafts. Missed PLC injury leads to the failure of ACL repair due to the joint instability.

PRESENTATION OF CASE

We are presenting a case of posttraumatic right ACL, PLC and lateral meniscus injury. The patient was taken to theatre for arthroscopic meniscectomy, ACL and PLC reconstruction. We had to harvest bilateral Gracilis and semitendinosus tendon grafts. Intraoperatively, we used a pump and after meniscectomy and ACL reconstruction the knee was quite swollen; we opted to offer a two-staged procedure for PLC reconstruction. Hence we had to preserve the graft in situ for the next procedure. Posterolateral corner reconstruction was done in a week's time and preserved ligament was found to be intact.

DISCUSSION

The fact that we did not have a tissue bank or facilities for cryopreservation of the harvested tendons at -80 °C or with liquid nitrogen at -179 °C yet we had to keep the harvested tendons safe.

CONCLUSION

In case of absence of graft and bone bank, tendon graft was in situ and found intact and ready to be used after seven days.

Biomechanical influence of deficient posterolateral corner structures on knee joint kinematics: A computational study

The posterolateral corner (PLC) structures including the popliteofibular ligament (PFL), popliteus tendon (PT) and lateral collateral ligament (LCL) are important soft tissues for posterior translational, external rotational, and varus angulation knee joint instabilities. The purpose of this study was to determine the effects of deficient PLC structures on the kinematics of the knee joint under gait and squat loading conditions. We developed subject-specific computational models with full 12-degree-of-freedom tibiofemoral and patellofemoral joints for four male subjects and one female subject. The subject-specific knee joint models were validated with computationally predicted muscle activation, electromyography data, and experimental data from previous study. According to our results, deficiency of the PFL did not significantly influence knee joint kinematics compared to an intact model under gait loading conditions. Compared with an intact model under gait and squat loading conditions, deficiency of the PT led to significant increases in external rotation and posterior translation, while LCL deficiency increased varus angulation. Deficiency of all PLC structures led to the greatest increases in external rotation, varus angulation, and posterior translation. These results suggest that the PT is an important structure for external rotation and posterior translation, while the LCL is important for varus angulation under dynamic loading conditions. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 9999:1-8, 2018.

Imaging of Athletic Injuries of Knee Ligaments and Menisci: Sports Imaging Series

Acute knee injuries are a common source of morbidity in athletes and if overlooked may result in chronic functional impairment. Magnetic resonance (MR) imaging of the knee has become the most commonly performed musculoskeletal MR examination and is an indispensable tool in the appropriate management of the injured athlete. Meniscal and ligamentous tearing are the most frequent indications for surgical intervention in sports injuries and an understanding of the anatomy, biomechanics, mechanisms of injury, and patterns of injury are all critical to accurate diagnosis and appropriate management. These will be discussed in reference to meniscal tears and injuries of the cruciate ligaments as well as injuries of the posterolateral and posteromedial corners of the knee. (©) RSNA, 2016.

Clinical outcomes after multiligament injured knees: medial versus lateral reconstructions

PURPOSE

The purpose of this study was to analyse the clinical outcomes of multiligament injured knees with respect to the medial collateral ligament and posteromedial corner (PMC) repair or reconstruction versus the posterolateral corner (PLC) reconstruction in patients operated according to a codified surgical protocol.

METHODS

Patients were divided into two groups depending on whether PMC or PLC was injured. Cruciate ligaments as well as PMC or PLC were reconstructed/repaired in a one-stage procedure. At minimum of 1-year follow-up, objective and subjective International Knee Documentation Committee (IKDC) forms, Lysholm score and sports activity level were recorded.

RESULTS

Thirty-nine patients with a median follow-up time of 57 months (range 12-129) were reviewed. No significant difference was found for functional scores between acute PMC and PLC subgroups. In Group PLC, subjective outcomes tend to be better in the acute than in chronic reconstruction subgroup.

CONCLUSIONS

A one-stage protocol with early surgery rather than delayed reconstruction produced better clinical outcomes whatever the injured collateral ligament, medial or lateral. In the future, early and chronic reconstructions as well as each injury pattern should be considered as separate entities in studies on multiple ligament injured knees to reach a better level of evidence.

LEVEL OF EVIDENCE

IV.

Popliteus impingement after TKA may occur with well-sized prostheses

PURPOSE

To determine the mechanisms and extents of popliteus impingements before and after TKA and to investigate the influence of implant sizing. The hypotheses were that (1) popliteus impingements after TKA may occur at both the tibia and the femur, and (2) even with an apparently well-sized prosthesis, popliteal tracking during knee flexion is modified compared to the preoperative situation.

METHODS

The location of the popliteus in three cadaver knees was measured using computed tomography, before and after implantation of plastic TKA replicas, by injecting the tendon with radiopaque liquid. The pre- and post-operative positions of the popliteus were compared from full extension to deep flexion using normosized, oversized, and undersized implants (one size increments).

RESULTS

At the tibia, TKA caused the popliteus to translate posteriorly, mostly in full extension: 4.1 ± 2 mm for normosized implants, and 15.8 ± 3 mm with oversized implants, but no translations were observed when using undersized implants. At the femur, TKA caused the popliteus to translate laterally at deeper flexion angles, peaking between 80° and 120°: 2 ± 0.4 mm for normosized implants and 2.6 ± 0.5 mm with oversized implants. Three-dimensional analysis revealed prosthetic overhang at the posterosuperior corner of normosized and oversized femoral components (respectively, up to 2.9 mm and 6.6 mm).

CONCLUSIONS

A well-sized tibial component modifies popliteal tracking, while an undersized tibial component maintains more physiologic patterns. Oversizing shifts the popliteus considerably throughout the full arc of motion. This study suggests that both femoro- and tibio-popliteus impingements could play a role in residual pain and stiffness after TKA.

Long-term clinical outcomes of combined BPTB ACL reconstruction and popliteus tendon plasty

PURPOSE

A deficiency of posterolateral structures significantly increases the varus load on the ACL, while a chronic ACL lesion, the increased tibial rotation and the repetitive non-physiological knee motion, could affect and damage the integrity of the popliteus tendon. Therefore, the aim of the present study was to report the very long clinical outcomes of a combined single-bundle BPTB ACL reconstruction and popliteus plasty according to Bousquets technique, for the treatment of combined chronic anterior and posterolateral laxities.

METHODS

Fifteen patients that underwent combined ACL reconstruction and popliteal plasty according to Bousquets technique were available at mean 26.8 ± 1.0 years (range 25.4-28.0 years). All the patients were evaluated clinically and 13 by means of KT-1000 Arthrometer as well. Subjective evaluation was performed with the subjective IKDC, WOMAC and a 0-10 VAS for pain scales.

RESULTS

At clinical evaluation, 10 patients (67 %) presented a negative anterior drawer test; Lachman test was negative in nine patients (60 %); the varus stress test was negative in eight (53 %); and the dial test was negative in all but one patient (93 %). Only two patients (15 %) presented a side-to-side difference >5 mm at the instrumented laxity evaluation.

CONCLUSION

The combined single-bundle BPTB ACL reconstruction and popliteal plasty according to Bousquets technique were able to produce very good long-term results, in terms of knee stability, subjective outcomes, functional results and return to sport activity, in case of chronic anterior and posterolateral laxities.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

Outcomes following anatomic fibular (lateral) collateral ligament reconstruction

PURPOSE

The purpose of this study was to investigate clinical outcomes following anatomic fibular (lateral) collateral ligament (FCL) reconstruction. It was hypothesized that anatomic FCL reconstruction would result in improved subjective clinical outcomes and a high patient satisfaction with outcome.

METHODS

All patients 18 years or older who underwent FCL reconstruction from April 2010 to January 2013 with no other posterolateral corner pathology were included in this study. Patient subjective outcome scores were collected preoperatively and at a minimum of 2 years postoperatively.

RESULTS

There were 43 patients (22 males, 21 females, median age = 28.3 years, range 18.7-68.8) included in this study. The median time from injury to surgery was 22 days. Follow-up was obtained for 88 % of patients (n = 36) with a mean follow-up of 2.7 years. The mean Lysholm score significantly improved from 49 (range 11-100) to 84 (range 55-100) postoperatively (p < 0.001). The mean WOMAC score significantly improved from 37 (range 3-96) to 8 (range 0-46) postoperatively (p < 0.001). The median SF-12 physical component subscale score significantly improved from 35 (range 22-58) to 56 (range 24-62) postoperatively (p < 0.001). The median SF-12 mental component subscale score did not show significant change preoperatively 54 (range 29-69) to postoperatively 55 (range 25-62). The median preoperative Tegner activity scale improved from 2 (range 0-10) to 6 (range 2-10) postoperatively (p < 0.001). The median patient satisfaction with outcome was 8 (range 1-10). Postoperative patient-reported outcome scores were not significantly different for patients who underwent concomitant ACL reconstruction compared to patients without ACL reconstruction.

CONCLUSION

An anatomic FCL reconstruction with a semitendinosus graft significantly improved patient function and yielded high patient satisfaction in the 43 patients. Additionally, there was no significant difference in patient-reported outcomes when accounting for concomitant ACL reconstruction.

LEVEL OF EVIDENCE

Level IV.