Influence and Clinical Significance of Knee Flexion Angle on the Anatomic Course of the Common Peroneal Nerve in the Posterolateral Corner of the Knee Joint

Background

Detailed knowledge of the anatomic course of the common peroneal nerve (CPN) is crucial for the surgical treatment of the posterolateral corner (PLC) of the knee.

Purpose

To investigate the relationship of the CPN to the PLC of the knee at different flexion angles.

Study Design

Descriptive laboratory study.

Methods

Ten healthy volunteers were recruited to undergo magnetic resonance imaging (MRI) of the knee joint at knee flexion angles of 0°, 30°, 60°, 90°, and 120°. MRI scans at 3 levels (joint line, tibial cut, and fibular tip) were evaluated to determine (1) the distance from the CPN to the PLC and (2) the distances between the CPN and the anterior-posterior and medial-lateral tibial axes. A 3-dimensional model of the knee joint created from MRI scans of a single participant was used to simulate the creation of a fibular tunnel for PLC reconstruction and investigate the relationship between the CPN, fibular tunnel, and guide pin.

Results

The CPN moved posteromedially with increased knee flexion angles. As the flexion angle increased, the distances from the CPN to the anterior-posterior axis and the PLC increased significantly, while the distance to the medial-lateral axis decreased significantly at all 3 measurement levels. The distances between the CPN and anterior-posterior and medial-lateral axes were significantly different among the different knee flexion angles at the different measurement levels. There were no significant differences in the mean distance from the CPN to the posterolateral border of the tibial plateau between 0° and 30° of flexion at the fibular tip level (P = .953). There were statistically significant differences in the distance from the CPN to the PLC of the tibial plateau at the different measurement levels. The 3-dimensional model demonstrated that the position of the CPN relative to the guide pin and the bone tunnel undergoes changes during knee flexion.

Conclusion

Changes in the knee flexion angle produced corresponding changes in the course of the CPN on the posterolateral aspect of the knee joint. The CPN moved posteromedially with increased knee flexion angles.

Clinical Relevance

Increasing the knee flexion angle during PLC reconstruction can effectively avoid direct injury of the CPN.

Fibular- Versus Tibiofibular-Based Reconstruction of the Posterolateral Corner of the Knee: A Systematic Review and Meta-analysis

BACKGROUND

Fibular- and tibiofibular-based reconstructions are the gold standard treatment for posterolateral corner (PLC) injuries of the knee. Despite comparable outcomes in biomechanical studies, clinical results comparing these constructs remain elusive with no consensus reached regarding the best treatment option.

PURPOSE

To perform a systematic review and meta-analysis to compare fibular- and tibiofibular-based techniques for posterolateral corner reconstruction. We aimed to identify whether any differences existed between the 2 techniques in terms of clinical outcomes and rotational and varus stability.

STUDY DESIGN

Meta-analysis; Level of evidence, 4.

METHODS

The Cochrane Controlled Register of Trials, PubMed, Medline, and Embase were used to perform a systematic review and meta-analysis using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) criteria with the following search terms ("posterolateral corner" OR "fibular collateral ligament" OR "lateral collateral ligament" OR "popliteus tendon" OR "popliteofibular ligament") AND ("reconstruction" OR "LaPrade" OR "Larson" OR "Arciero"). Data pertaining to all patient-reported outcome measures (PROMs), postoperative complications, and valgus and rotational stability were extracted from each study. The pooled outcome data were analyzed by random- and fixed-effects models.

RESULTS

After abstract and full-text screening, 6 clinical studies were included. In total, there were 183 patients, of which 90 received fibular-based and 93 tibiofibular-based reconstruction. The majority of studies used similar surgical techniques regarding tunnel orientation, attachment sites, and graft fixation sequence. There were no differences between the groups in terms of PROMs and subjective knee scores at a mean of 20.3 months. The techniques were equally effective in restoring varus and rotational stability. Subgroup analysis revealed that the stability of a posterior cruciate ligament reconstruction postoperatively was not affected by either construct.

CONCLUSION

Both constructs had comparable clinical outcomes and were equally effective in restoring varus and rotational stability for PLC knee injuries. The fibular-based technique may offer advantages in view of being less technically demanding and invasive and requiring fewer grafts with a quicker operative time. However, higher quality studies are required to reinforce or refute such conclusions, as the majority of studies in this review were poor to fair quality.

Superior Bone Microarchitecture in Anatomic Versus Nonanatomic Fibular Drill Tunnels for Reconstruction of the Posterolateral Corner of the Knee

Background:

Several fibula-based reconstruction techniques have been introduced to address ligamentous injuries of the posterolateral corner of the knee. These techniques involve a drill tunnel with auto- or allograft placement through the proximal fibula.

Purpose:

To determine the skeletal microarchitecture of the proximal fibula and its association with age and to compare the microarchitecture within the regions of different drill tunnel techniques for reconstruction of the posterolateral corner.

Study Design:

Descriptive laboratory study.

Methods:

A total of 30 human fibulae were analyzed in this cadaveric imaging study. High-resolution peripheral quantitative computed tomography measurements were performed in a 4.5 cm–long volume of interest at the proximal fibula. Three-dimensional microarchitectural data sets of cortical and trabecular compartments were evaluated using customized scripts. The quadrants representing the entry and exit drill tunnel positions corresponding to anatomic techniques (LaPrade/Arciero) and the Larson technique were analyzed. Linear regression models and group comparisons were applied.

Results:

Trabecular microarchitecture parameters declined significantly with age in women but not men. Analysis of subregions with respect to height revealed stable cortical and decreasing trabecular values from proximal to distal in both sexes. Along with a structural variability in axial slices, superior values were found for the densitometric and microarchitectural parameters corresponding to the fibular drill tunnels in the anatomic versus Larson technique (mean ± SD; bone volume to tissue volume at the entry position, 0.273 ± 0.079 vs 0.175 ± 0.063; P < .0001; cortical thickness at the entry position, 0.501 ± 0.138 vs 0.353 ± 0.081 mm; P < .0001).

Conclusion:

Age represented a relevant risk factor for impaired skeletal microarchitecture in the proximal fibula in women but not men. The region of drill tunnels according to anatomic techniques showed superior bone microarchitecture versus that according to the Larson technique.

All-Arthroscopic Treatment of Combined Posterior Cruciate Ligament and Posterolateral Corner Instability

Injuries to the posterolateral corner (PLC) of the knee are uncommon, and usually associated with other ligamentous injuries. A combined posterior cruciate ligament (PCL) and PLC tear is the most frequent combination. Several studies describe anatomic reconstructive techniques using an open approach with large incisions and extensive exploration of the posterolateral structures. This Technical Note describes an all-arthroscopic technique as a safe and efficient treatment of combined PCL and PLC instability using the trans-septal approach.

Biomechanical Assessment of Knee Laxity After a Novel Posterolateral Corner Reconstruction Technique

BACKGROUND

Different techniques to restore knee stability after posterolateral corner (PLC) injury have been described. The original anatomic PLC reconstruction uses 2 separate allografts to reconstruct the PLC. Access to allograft tissue continues to be a significant limitation of this technique, which led to the development of a modified anatomic approach utilizing a single autologous semitendinosus graft fixed on the tibia with an adjustable suspensory loop to enable differential tensioning of the PLC components.

PURPOSE/HYPOTHESIS

The purpose of this study was to compare the modified anatomic technique with the original anatomic reconstruction in terms of varus and external rotatory laxity in a cadaveric biomechanical model. The hypothesis was that both techniques would restore varus and external rotatory laxity after a simulated complete PLC injury.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eight pairs of fresh-frozen cadaveric knee specimens were tested to compare the 2 techniques. Varus and external tibial rotation laxity of the knee were measured while applying 10-N·m varus and 5-N·m external rotatory torques at 0°, 30°, 60°, and 90° of flexion. These measurements were tested under 3 conditions: (1) intact fibular collateral ligament, popliteal tendon, and popliteofibular ligament; (2) complete transection of the fibular collateral ligament, popliteal tendon, and popliteofibular ligament; (3) after PLC reconstruction with either the modified (n = 8) or the original (n = 8) technique.

RESULTS

After PLC reconstruction, varus laxity was restored with no statistically significant differences from the intact condition after both reconstruction techniques. Similar outcomes were observed for external rotation in extension; however, in terms of the external rotation limit with respect to the intact joint, significant reductions of mean ± SD 4.1°± 6.3° (P = .036) and 5.1°± 6.6° (P = .016) were recorded with the modified technique at 60° and 90° of flexion, respectively. No significant effect was observed on the neutral flexion kinematics from 0° to 90° of flexion, and no significant differences were observed between reconstructions (P = .222).

CONCLUSION

Both PLC reconstruction techniques restored the normal native varus as compared with the intact knee. Although the modified technique constrained end-range external rotation at 60° and 90° of flexion, no differences were noted with neutral flexion kinematics. Care should be taken when tensioning in the modified technique so that the tibia is in a neutral position to avoid overconstraining the knee.

CLINICAL RELEVANCE

The modified technique may prove useful in situations where there are limited graft options, particularly where allografts are not available or are restricted.

Classification of the popliteofibular ligament

PURPOSE

The purpose of this study was to characterize the morphological variations in the distal attachment of the popliteofibular ligament (PFL) and create an accurate classification for use in planning surgical procedures in this area and in evaluating radiological imaging.

METHODS

One hundred and thirty-seven lower limbs of body donors fixed in 10% formalin solution were examined for the presence and course of the popliteofibular ligament.

RESULTS

The PFL was present in 88.3% of cases. We propose the following three-fold classification: type I (72.3%), the most common type, characterized by the attachment onto the apex of the head of the fibula, type II (8.7%), characterized by a bifurcation, with the dominant band inserting on the anterior slope of the styloid process of the fibula and the smaller band onto the posterior surface of the styloid process of the fibula and type III (7.3%), characterized by a double PFL: the first PFL (main) originated from the popliteus tendon and inserted onto the anterior slope of the styloid process of the fibula, while the second originated from the musculotendinous junction of the popliteus muscle and inserted on the posterior surface of the styloid process of the fibula.

CONCLUSION

The PFL was characterized by high morphological variation, as reflected in our proposed classification. This variation may present clinical and biomechanical issues for both medical personnel and researchers. Our proposed classification may be valuable for clinicians who evaluate and perform surgical procedures within the knee joint area.

Incidence of Intraoperative and Postoperative Complications After Posterolateral Corner Reconstruction or Repair: A Systematic Review of the Current Literature

BACKGROUND

Posterolateral corner (PLC) injuries of the knee are being increasingly recognized and treated in current orthopaedic practice. While there are numerous systematic reviews evaluating the management and outcomes after PLC injuries, there are limited data investigating complications after PLC reconstruction or repair.

PURPOSE

To systematically review the literature to determine the incidence of postoperative complications after the surgical treatment of PLC injury.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

The Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, PubMed (2008-2019), Embase (2008-2019), and MEDLINE (2008-2019) were queried for literature reporting on PLC reconstruction or repair, with or without concomitant ligamentous or meniscal surgery. Data including type of surgery performed, concomitant procedures, and follow-up time were extracted. Complications recorded included intra- and postoperative complications.

RESULTS

After the intra- and postoperative complication data of 60 studies (1747 cases) were combined, surgical management of PLC injuries was associated with an intraoperative complication rate of 0.34% (range, 0%-2.8%) and a postoperative complication rate of 20% (range, 0%-51.2%). The most common postoperative complication was arthrofibrosis (range, 0%-20%). The overall infection rate was 1.3% (range, 0%-10%). Four cases of postoperative common peroneal nerve palsy were reported. Failure of reconstruction or repair was reported in 164 (9.4%) of all cases examined (range, 0%-37.1%).

CONCLUSION

Although the intraoperative rate of complications during PLC reconstructions is low, postoperative complications rates of 20% can be expected, including arthrofibrosis, infection, and neurovascular injury. PLC structures repaired or reconstructed failed in 9.4% of the cases.

Diving for the Basketball: An Isolated Popliteus Rupture in an Adolescent Female with 6 Year Follow-Up

Popliteus tendon injuries most often occur in a traumatic setting with damage to multiple other knee structures. Isolated popliteal injuries, however, are rare. To our knowledge, there are no cases of a female pediatric patient with an intrasubstance popliteal tendon rupture in the current literature. This case report aims to illustrate symptoms, imaging, and treatment of an isolated popliteal tendon rupture in an adolescent female. An athletic 14-year-old female presented with right knee pain 4 weeks after a basketball injury in which she dove for the ball and fell, twisting and striking her knee. She had diffuse pain on both sides of the right knee for 3 weeks and pain with running, jumping or twisting. The knee exam was otherwise unremarkable. A right knee MRI demonstrated a complete rupture of the popliteal tendon. No other knee injuries were visualized. The patient was treated non-operatively and gradually returned to normal activities and sports at 6 weeks post injury. On 6-year follow up, the patient had no residual pain or instability and was able to play basketball without difficulty. Isolated popliteal tendon ruptures are extremely rare and difficult to diagnose given non-specific clinical exam findings. While these ruptures can be difficult to visualize on MRI, imaging can help to clarify the diagnosis by ruling out other injuries with similar clinical presentations. In the case of this young and active patient, diagnosis and full recovery without limitations were achieved with 6 weeks of conservative management.

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.

Current concepts on the morphology of popliteus tendon and its clinical implications

In this review we described the anatomy and biomechanics of popliteus muscle and its tendon. Furthermore, we combined the anatomy with clinics and discussed a wide spectrum of disorders regarding the popliteus and its musculotendinous complex. There are three main anatomical regions of the popliteus musculotendinous complex: the proximal origin, the mid-portion, the distal part on the tibia. The unique localisation and various origins of the tendon, connected with structures such as fibular head, Wrisberg, Humphrey and posterior cruciate ligament, lateral meniscus, medial collateral ligament, give an implication to diagnosis and treatment. Popliteus dysfunction is often overlooked, that is the reason why diagnosis and treatment of its injuries is mostly insufficient. Repetitive or acute direct varus forces, when the tibia is in external rotation, and knee hyperextension or flexion with forced external rotation of the tibia, are the main mechanisms of trauma. Popliteus injuries mainly affect the athletic population and lead to severe activity limitations. Chronic disorders of the popliteus tendon, less known, are often described as tendinopathy and are frequently seen in runners. Their symptoms can mimic the lateral meniscal tears. On the other hand, high-energy traumatic injuries of the popliteus tendon often accompany complex, multi ligamentous injuries seen in competitive sports. We also presented the implication of popliteus tendon in knee arthroplasty, due to its particular exposition to iatrogenic trauma during surgery. The issues such as proper tibial component location and well-designed cut systems are crucial to avoid the popliteus impingement and preserve its structure.

An Unusual Complex Posterolateral Osteoligamentous Injury of the Knee in an Adolescent

We present an unusual and complex case of a 16-year-old adolescent male who injured his right knee and sustained combined avulsion injuries of posterior cruciate ligament (PCL) at the tibial insertion site, iliotibial band at lateral tibial condyle, and lateral collateral ligament (LCL) at femoral insertion site akin to osteoligamentous posterolateral corner injury. Anatomical reduction of the femoral LCL avulsion fragment was performed and fixed with a two 4-mm partially threaded cancellous screw. Iliotibial band avulsion was buttressed using Ellis t-plate and fixed with two 4-mm partially threaded cancellous screws. PCL avulsion fracture was conservatively treated owing to minimal displacement. At one-year follow-up, the patient was pain free with a range of motion of 0 to 150 degrees of flexion and had a pain free knee with no instability. Posterolateral corner injury in the patient was very significant as it involved LCL avulsion and iliotibial band avulsion, both of which are part of the posterolateral structures of the knee and also involve the growth plate. Fixation of the avulsion of Gerdy's tubercle with the buttress plate helps to provide additional stability to counteract the deforming forces of the iliotibial band. LCL is also the major stabilizer against varus forces, and hence fixation is required for stability while preventing growth disturbance. PCL avulsion can be treated conservatively in those patients where the fragment is undisplaced or minimally displaced. A good outcome can be achieved in skeletally immature patients who have osteoligamentous posterolateral corner injuries with associated avulsion fractures by using appropriate anatomical reduction and surgical fixation.

No Difference Between Posterolateral Corner Repair and Reconstruction With Concurrent ACL Surgery: Results From a Prospective Multicenter Cohort

Background:

Injuries to the posterolateral corner (PLC) may occur concurrently with anterior cruciate ligament (ACL) injury.

Purpose/Hypothesis:

This study evaluated the outcomes of patients who underwent operative management of PLC injuries concurrently with ACL reconstruction in a prospective multicenter cohort. We hypothesized that there would be no differences in outcomes between patients who were treated with PLC repair and PLC reconstruction.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Patients undergoing ACL reconstruction were enrolled into a prospective longitudinal multicenter cohort between 2002 and 2008. Those with complete 6-year follow-up data (patient-reported outcomes and subsequent surgery information) were identified. Excluded from the study were patients with posterior cruciate ligament injuries. Patients who underwent PLC repair were compared with those who underwent PLC reconstruction with regard to interval from injury to surgery, need for revision surgery, and long-term outcomes at 6 years.

Results:

During the identified time frame, 3026 identified patients underwent primary ACL reconstruction; 34 (1.1%) also underwent concurrent PLC surgery (15 repairs, 19 reconstructions [18 allografts, 1 autograft]). With the numbers available, we did not detect significant differences between groups regarding the rate of meniscal or chondral injuries. Median time to PLC reconstruction was 121 days as compared with 19 days for concurrent ACL reconstruction and PLC repair (P = .01). There were no between-group differences in Marx activity scores prior to surgery (P = .4). At 6-year follow-up, there were no between-group differences in Knee injury and Osteoarthritis Outcome Score (P = .36-.83) or International Knee Documentation Committee score (P = .84); however, patients treated with PLC reconstructions had lower Marx activity scores (4.1 vs 9.4; P = .02). There was 1 ACL revision in the PLC reconstruction group, and 1 of the PLC repairs was revised to a reconstruction during the follow-up period.

Conclusion:

Good outcomes were achieved at 6-year follow-up with both repair and reconstruction of PLC injuries treated concurrently with ACL reconstruction. The PLC reconstruction group had lower activity levels 6 years after surgery. The present data suggest that, for appropriately selected patients undergoing acute surgical treatment of combined ACL and PLC injuries, PCL repair can achieve good long-term outcomes.

Types of posterolateral corner injury associated with both bundle and selective-bundle ACL tears

BACKGROUND

It is unknown whether a selective-bundle tear of the anterior cruciate ligament (ACL) shows a different prevalence of posterolateral corner (PLC) injury than a both-bundle tear.

PURPOSE

The prevalence of injury of PLC stabilizer in relation to the type of combined ACL tear (both-bundle and selective-bundle tears) has been investigated.

MATERIAL AND METHODS

This retrospective study included 94 patients who were diagnosed with an ACL tear after knee joint magnetic resonance imaging and underwent arthroscopic surgery. We compared the prevalence of each lesion in relation to the type of ACL injury and the type of selective-bundle tear. We used Fischer exact tests to compare the prevalence of each lesion in relation to the type of ACL injury and the type of selective-bundle tear.

RESULTS

Both-bundle tears occurred in 55 cases (56%) and selective-bundle tears in 39 cases (44%). The most common PLC injury with an ACL tear was inferior popliteomeniscal fascicle (PMF) injury, followed by superior PMF injury. The prevalence of each PLC injury was higher for both-bundle tears than selective-bundle tears, with the exception of popliteus tendon injury diagnosed by reader 1 (P.H.J). However, these differences were statistically significant for superior PMF injury only ( p < 0.05). The prevalence of PLC injury was unrelated to the type of selective-bundle tear (anteromedial vs posterolateral).

CONCLUSION

Superior PMF injury is more common in both-bundle tears than selective-bundle tears. There is no statistically significant difference in the prevalence of PLC injury between both-bundle tears and selective-bundle tears.

A Biomechanical Comparison of the Arciero and LaPrade Reconstruction for Posterolateral Corner Knee Injuries

Background:

Injury to the posterolateral corner (PLC) of the knee requires reconstruction to restore coronal and rotary stability. Two commonly used procedures are the Arciero reconstruction technique (ART) and the LaPrade reconstruction technique (LRT). To the authors’ knowledge, these techniques have not been biomechanically compared against one another.

Purpose:

To identify if one of these reconstruction techniques better restores stability to a PLC-deficient knee and if concomitant injury to the proximal tibiofibular joint or anterior cruciate ligament affects these results.

Study Design:

Controlled laboratory study.

Methods:

Eight matched-paired cadaveric specimens from the midfemur to toes were used. Each specimen was tested in 4 phases: intact PLC (phase 1), PLC sectioned (phase 2), PLC reconstructed (ART or LRT) (phase 3), and tibiofibular (phase 4A) or anterior cruciate ligament (phase 4B) sectioning with PLC reconstructed. Varus angulation and external rotation at 0º, 20º, 30º, 60º, and 90º of knee flexion were quantified at each phase.

Results:

In phase 3, both reconstructions were effective at restoring laxity back to the intact state. However, in phase 4A, both reconstructions were ineffective at stabilizing the joint owing to tibiofibular instability. In phase 4B, both reconstructions had the potential to restrict varus angulation motion. There were no statistically significant differences found between reconstruction techniques for varus angulation or external rotation at any degree of flexion in phase 3 or 4.

Conclusion:

The LRT and ART are equally effective at restoring stability to knees with PLC injuries. Neither reconstruction technique fully restores stability to knees with combined PLC and proximal tibiofibular joint injuries.

Clinical Relevance:

Given these findings, surgeons may select their reconstruction technique based on their experience and training and the specific needs of their patients.

Fibular Collateral Ligament: Varus Stress Radiographic Analysis Using 3 Different Clinical Techniques

Background:

Fibular collateral ligament (FCL) tears are challenging to diagnose. Left untreated, FCL tears lead to residual ligament instability and increased joint loading on the medial compartment of the knee. Additionally, when a concomitant anterior cruciate ligament (ACL) reconstruction is performed, increased forces on reconstruction grafts occur, which may lead to premature graft failure. Stress radiographs constitute a reliable and validated technique for the objective assessment of a complete grade III FCL tear.

Purpose:

To evaluate side-to-side difference (SSD) values of lateral compartment gapping on varus stress radiographs in patients with a grade III injury to the FCL. Additionally, to evaluate the reliability and reproducibility of 3 different measurement techniques that used various radiographic reference points.

Study Design:

Cohort study (diagnosis); Level of evidence, 2.

Methods:

Inclusion criteria were patients who sustained an FCL with or without a concomitant ACL injury and underwent a combined FCL + ACL reconstruction between 2010 and 2016. Patients were excluded if they had a complete posterolateral corner injury, open physes, intra-articular fracture, meniscal root tear, other ligament injury, or prior surgery on either knee. All FCL tears were diagnosed with a clinical varus stress examination at 0° and 20° of knee flexion and varus stress radiographs at 20° of knee flexion measured in 3 different locations. The SSD for lateral compartment gapping was obtained from the varus stress radiographs and then statistically compared for interrater and intrarater reliability.

Results:

A total of 98 consecutive patients (50 males, 48 females; 13 isolated FCL injuries, 85 combined ACL + FCL injuries) with mean age 33.6 years (range, 18-69 years) were included. Measurement techniques 1, 2, and 3 had mean ± SD lateral compartment SSDs of 2.4 ± 0.20 mm, 2.2 ± 0.20 mm, and 2.0 ± 0.03 mm, respectively (no significant differences). Interrater reliabilities for the 3 measuring techniques were 0.83, 0.86, and 0.91, respectively, while intrarater reliabilities were 0.99, 0.77, and 0.99, respectively.

Conclusion:

This study demonstrated a lower SSD value of 2.2 mm to be consistent with a grade III FCL tear on clinician-applied varus stress radiographs in the clinical setting. Although all SSD measurement locations had excellent reliability, the method using the midpoint of the lateral tibial plateau was found to be the most reproducible.

A Biomechanical Assessment of Biceps Femoris Repair Techniques

Background:

Knee injuries encountered in clinical practice can involve avulsions of the biceps femoris from the fibula and proximal tibia. Advances in tendon repair methods now allow for repairs with increased surface areas using modern suture anchor techniques. Despite descriptions of repair techniques, there are no biomechanical studies on the biceps femoris for comparison.

Purpose/Hypothesis:

The objective of this controlled laboratory study was to determine the failure load of the native biceps femoris distal insertion and to evaluate modern repair techniques. Our hypothesis was 2-fold: (1) Suture repairs to the tibia and fibula would perform better on tensile testing than repairs to the fibula alone, and (2) complex bridge repairs, similar to those frequently used in rotator cuff surgery, would perform better on tensile testing than simple repairs.

Study Design:

Controlled laboratory study.

Methods:

A total of 40 paired, fresh-frozen cadaveric specimens were dissected, identifying the biceps femoris and its insertion on the proximal tibia and fibula. The native biceps femoris footprint was left intact in 8 specimens and tested to failure on a uniaxial materials testing machine evaluating tensile properties, while in the other 32 specimens, the biceps femoris insertion was dissected using a No. 15 scalpel blade, underwent repair, and was then tested to failure on a uniaxial materials testing machine evaluating tensile properties. Four repair constructs were evaluated, with 8 specimens allocated for each: construct 1 involved a simple repair (ie, passing suture through tissue in a running Krackow fashion and tying at the anchor site) to the fibula with 2 suture anchors, construct 2 involved a simple repair to the fibula and tibia with 3 suture anchors, construct 3 was a fibular repair with a tibial suture bridge involving the fibula and tibia and 3 suture anchors, construct 4 involved a transosseous repair through the fibula and 1 suture anchor on the tibia. Analysis of variance was used to evaluate for significance of the mean failure load and stiffness between groups.

Results:

The mean (±95% CI) failure loads were the following: native biceps femoris, 1280 ± 247.0 N; simple fibular repair, 173 ± 84.6 N; simple fibular and tibial repair, 176 ± 48.1 N; fibular repair with tibial suture bridge, 191 ± 78.5 N; and transosseous repair, 327 ± 66.3 N. The mean stiffness values were the following: native, 46 ± 13.0 N/mm; simple fibular repair, 16 ± 5.1 N/mm; simple fibular and tibial repair, 14 ± 5.4 N/mm; fibular repair with tibial suture bridge, 13 ± 2.8 N/mm; and transosseous repair, 15 ± 2.5 N/mm. Interconstruct comparison of failure loads revealed no statistical difference between constructs utilizing anchors alone. The transosseous repair showed a significant difference for the failure load when compared with each anchor repair construct (P = .02, .02, and .04 for constructs 1, 2, and 3, respectively). Interconstruct comparison of stiffness revealed no statistical difference between all constructs (P > .86). None of the repair techniques re-created the failure load or stiffness of the native biceps femoris tendon (P = .02).

Conclusion:

In this biomechanical study, no difference was found between the mean failure loads of different biceps femoris repair constructs involving suture anchors alone and No. 2 braided polyester and ultra–high-molecular-weight polyethylene suture. A technique involving transosseous fibular tunnels and 2-mm suture tape illustrated a greater mean failure load than repairs relying on suture anchors for fixation.

Clinical Relevance:

Understanding the tensile performance of biceps femoris repair constructs aids clinicians with preoperative and intraoperative decisions. Current biceps femoris repair techniques do not approximate the native strength of the tendon. A transosseous style of repair offers the highest failure load.

[Minimally invasive reconstruction of the posterolateral corner with simultaneous replacement of the anterior cruciate ligament for complex knee ligament injuries]

OBJECTIVE

To evaluate and describe the results of a simultaneous reconstruction with minimally invasive technique of the posterolateral complex (PLC) and the anterior cruciate ligament (ACL).

MATERIAL AND METHODS

ACL and PLC reconstruction was performed in seven patients using the technique described, in the period from March to November 2012. All patients were evaluated at six months after the procedure using IKDC and IKSS subjective tests. Their return to work activities and their level of satisfaction were assessed.

RESULTS

Six male and one female patients ranging in age between 26 and 46 years were evaluated. The injuries were mostly caused by sports related accidents. All patients were economically active and required an average period of three months of disability. The assessment and outcomes at six months, according to the IKDC scale, were: one patient with IKDC A, four with IKDC B, one patient with C, and one with D. In the subjective scale IKSS, 80% averaged a knee stability of over 90 points, a patient had a 100-point scale and another, of 70 points.

Management of combined injuries of the posterior cruciate ligament and posterolateral corner of the knee: a systematic review

BACKGROUND

Approximately 60% of posterior cruciate ligament (PCL) injury are associated with a posterolateral corner (PLC) tear.

SOURCES OF DATA

We performed a systematic review of the literature according to the PRISMA guidelines. The following key words were searched on Medline, Cochrane, EMBASE, Google Scholar, and Ovid: 'posterior cruciate ligament' or 'PCL' with 'posterolateral corner' or 'PLC' and 'chronic'; 'injury'; 'management'; 'reconstruction'; 'outcomes'; 'complications'.

AREAS OF AGREEMENT

There was a statistically significant improvement of all clinical scores after surgery regardless of the procedure performed to reconstruct both PCL and PLC.

AREAS OF CONTROVERSY

No randomized control trials were identified on the topic. Standardized methods of functional outcomes assessment are necessary to improve communication on the functional results of the management of PC-PLC.

GROWING POINTS

Single stage surgical reconstruction of PCL and PLC is recommended in patients with posterolateral rotatory instability of the knee.

AREAS TIMELY FOR DEVELOPING RESEARCH

Adequately powered randomized trials with appropriate subjective and objective outcome measures are necessary to reach definitive conclusions.

[Classification, diagnosis, and treatment system of posteromedial structure and posterolateral corner injury in knee dislocation]

Objective

To review the research progress of diagnosis and treatment system for knee dislocation (KD) based on the stage and classification of posteromedial structure and posterolateral corner injury, so as to provide guidance for clinical work.

Methods

The relevant literature on the classification, diagnosis and treatment was extensively reviewed.

Results

At present, the criterion of the stage and classification of KD mainly include classification based on the size of the injury energy, Kennedy classification, and the improved Schenck classification, but they are not perfect because of no stage and classification of multiple ligament injury and no standardized treatment of different injuries. Hua Xi Knee Dislocation and Multiple Ligament Injury (HX-KDMLI) has optimum plan for injury treatment of posteromedial structure and posterolateral corner injury in KD based on stage and classification.

Conclusion

At present, there is no unified opinion on stages and classifications of the posteromedial structure and posterolateral corner injury in KD as well as on diagnosis and treatment. HX-KDMLI has certain feasibility for the stage and classification of the posteromedial structure and posterolateral corner injury in KD, to a certain extent, it can be used as reference for the diagnosis and treatment of KD.

CONSERVATIVE MANAGEMENT OF AN ISOLATED GRADE III LATERAL COLLATERAL LIGAMENT INJURY IN AN ADOLESCENT MULTI-SPORT ATHLETE: A CASE REPORT

STUDY DESIGN

Case report.

BACKGROUND

Isolated, grade III lateral collateral ligament knee injuries are an uncommon traumatic injury with little guidance available in the literature for conservative management and prognosis for return to sport. The purpose of this case report is to describe the clinical decision-making in both differential diagnosis and physical therapy management of an isolated grade III lateral collateral ligament sprain in an adolescent multi-sport high school athlete.

CASE DESCRIPTION

A 16 year-old male, high school, multi-sport athlete (cross country, wrestling, track and field) sustained a traumatic knee injury during a wrestling match when his involved lower extremity was forcefully externally rotated by his opponent. Initial clinical presentation revealed pain and increased laxity with varus stress testing of the left knee, which was subsequently identified via MRI as a complete lateral collateral ligament rupture (grade III). A conservative physical therapy program was developed targeting the active and neuromuscular subsystems, theorized to compensate for the lack of an intact lateral collateral ligament.

OUTCOMES

The subject attended 18 visits of physical therapy over a period of 12 weeks. His rehabilitation program focused on functional strengthening of the posterolateral corner, enhancement of neuromuscular control, and graded progression to sports specific drills. Return to play decisions were based on a combination of lower extremity functional performance measures, condition specific outcome measures and subjective performance on sports specific tasks. At discharge from physical therapy, he reported 0/10 pain, scored a 76/80 on the Lower Extremity Functional Scale, and was able to return to competitive track and field events.

DISCUSSION

Few descriptions in the literature exist for the conservative management of isolated, grade III lateral collateral ligament injuries. A program of selective functional strengthening, proprioceptive training, and graded sport specific activities may allow these individuals to return to sport with conservative management.

LEVELS OF EVIDENCE

4 (Single Case Report).

Two cases of chronic knee pain caused by unusual injuries to the popliteus tendon

Injuries to the popliteus tendon are less frequent than injuries to the menisci or ligamentous structures of the knee. When they do occur, injuries to the popliteus tendon tend to be the result of trauma and associated with injuries to other components of the knee. The most commonly seen injuries include tears at the musculotendinous junction and avulsion tears at the lateral femoral condyle insertion site. This report presents two unusual injuries of the popliteus tendon in patients with chronic knee pain: an isolated split tear of the tendon and a subluxed tendon residing within the lateral joint space.

A Systematic Review of the Outcomes of Posterolateral Corner Knee Injuries, Part 2: Surgical Treatment of Chronic Injuries

BACKGROUND

There are a variety of reported surgical techniques outcomes of chronic grade III posterolateral corner (PLC) knee injuries. It is unknown if outcomes differ among the various surgical treatments.

PURPOSE

To systematically review the literature and report subjective and objective outcomes for surgical treatment strategies for chronic grade III PLC injuries to determine the optimal surgical technique.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic review of the literature including Cochrane, PubMed, Medline, and Embase was performed. The following search terms were used: posterolateral corner knee, posterolateral knee, posterolateral instability, multiligament knee, and knee dislocation. Inclusion criteria were outcome studies of surgical treatment for chronic PLC knee injuries with a minimum 2-year follow-up, subjective outcomes, objective outcomes including varus stability, and subgroup data on PLC injuries. Two investigators independently reviewed all abstracts. Accepted definitions of varus stability on examination or stress radiographs, and the need for revision surgery, were used to categorically define success and failure.

RESULTS

Fifteen studies with a total of 456 patients were included in this study. The 15 studies included 5 with level 3 evidence and 10 with level 4 evidence. The mean age of the patients in each study ranged from 25.2 to 40 years, the reported mean time to surgery ranged from 5.5 to 52.8 months, and the mean follow-up duration ranged from 2 to 16.3 years. Mean postoperative Lysholm scores ranged from 65.5 to 91.8; mean postoperative International Knee Documentation Committee (IKDC) scores ranged from 62.6 to 86.0. Based on objective stability, there was an overall success rate of 90% and a 10% failure rate of PLC reconstruction. A variety of surgical techniques were reported.

CONCLUSION

Chronic PLC injuries were reconstructed in all studies, and while techniques varied, the surgical management of chronic PLC injuries had a 90% success rate and a 10% failure rate according to the individual investigators' examination or stress radiographic assessment of objective outcomes. More than half of the 456 patients had a combined posterior cruciate ligament-PLC injury. Surgical techniques included variations of fibular slings, capsular shifts, and anatomic-based techniques (fibular tunnel and tibial tunnel). Further research is needed to determine the optimal surgical technique for treating chronic grade III PLC injuries.

A Systematic Review of the Outcomes of Posterolateral Corner Knee Injuries, Part 1: Surgical Treatment of Acute Injuries

BACKGROUND

There is a paucity of outcome data to guide the surgical treatment of acute grade III posterolateral corner (PLC) knee injuries.

PURPOSE

To systematically review the literature to compare clinical outcomes of the treatment for acute grade III PLC injuries.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic review of the literature including Cochrane, PubMed, Medline, and Embase was performed. The following search terms were used: posterolateral corner knee, posterolateral knee, posterolateral instability, multiligament knee, and knee dislocation. Inclusion criteria were outcome studies of surgically treated acute PLC injuries with a minimum 2-year follow-up, subjective outcomes, objective outcomes including varus stability, and subgroup data on PLC injuries. Two investigators independently reviewed all abstracts. Accepted definitions of varus stability on examination or stress radiographs and the need for revision surgery were used to categorically define success and failure.

RESULTS

Eight studies with a total of 134 patients were included. The mean patient age was reported in 7 studies (range, 21-31.5 years). The mean time to surgery was reported in 5 studies (range, 15-24.3 days); surgery was performed within 3 weeks in the other 3 studies. Four studies reported International Knee Documentation Committee scores (range, 78.1-91.3); 5 studies reported Lysholm scores (range, 87.5-90.3). Only 3 studies obtained bilateral varus stress radiographs. Based on an objective evaluation with varus stress examinations or radiographs, there was an overall success rate of 81% and failure rate of 19%. In 2 studies, the fibular collateral ligament and popliteus tendon were repaired and staged cruciate reconstruction performed in most patients; there were 17 failures of 45 patients (38%). In the remainder of the studies, patients were treated with local tissue transfer, hybrid repair for amenable structures or reconstruction for midsubstance tears, or reconstruction of all torn structures; the failure rate was 9%.

CONCLUSION

The repair of acute grade III PLC injuries and staged treatment of combined cruciate injuries were associated with a substantially higher postoperative PLC failure rate. Further research is required to identify the reconstruction technique that provides optimal subjective and objective outcomes.

Reconstruction of the Posterolateral Corner After Sequential Sectioning Restores Knee Kinematics

Background:

Various surgical techniques to treat posterolateral knee instability have been described. To date, the recommended treatment is an anatomic form of reconstruction in which the 3 key structures of the posterolateral corner (PLC) are addressed: the popliteofibular ligament, the popliteus tendon, and the lateral collateral ligament.

Purpose/Hypothesis:

The purpose of this study was to identify the role of each key structure of the PLC in kinematics of the knee and to biomechanically analyze a single-graft, fibular-based reconstruction that replicates the femoral insertions of the lateral collateral ligament and popliteus to repair the PLC. The hypothesis was that knee kinematics can be reasonably restored using a single graft with a 2-strand “modified Larson” technique.

Study Design:

Descriptive laboratory study.

Methods:

Eight fresh-frozen cadaveric knees were used in this study. We conducted sequential sectioning of the popliteofibular ligament (PFL) and then subsequently the popliteal tendon (PT), the lateral collateral ligament (LCL), and the anterior cruciate ligament (ACL). We then reconstructed the ACL first and then the posterolateral corner using the modified Larson technique. A surgical navigation system was used to measure varus laxity and external rotation at 0°, 30°, 60°, and 90° with a 9.8-N·m varus stress and 5-N·m external rotation force applied to the tibia.

Results:

In extension, varus laxity increased only after the sectioning of the lateral collateral ligament. At 30° of flexion, external rotation in varus and translation of the lateral tibial plateau increased after the isolated popliteofibular ligament section. From 60° to 90° of flexion, translation and mobility of the lateral plateau section increased after sectioning of the PFL. After reconstruction, we observed a restoration of external varus rotation in extension and translation of the lateral tibial plateau at 90° of flexion. This technique provided kinematics similar to the normal knee.

Conclusion:

The PFL has a key role between 30° and 90° of flexion, and the lateral collateral ligament plays a role in extension. Reconstruction with the modified Larson technique restores these 2 complementary stabilizers of the knee.

Clinical Relevance:

Although there are many different techniques to reconstruct the PLC-deficient knee, this study indicates that a single-graft, fibular-based reconstruction of the LCL and PT may restore varus and external rotation laxity to the knee.

Posterolateral rotatory instability of the knee after arthroscopic subtotal lateral meniscectomy: a case report

A 33-year-old Caucasian woman came to our attention complaining of lateral knee pain on the left side, severe external instability associated with varus malalignment, and difficulties in weight-bearing activities. The symptoms had appeared following two lateral meniscectomies on her discoid meniscus, performed elsewhere. The patient was initially submitted to an allograft meniscus transplantation exploiting the unloaded condition of lateral compartment and obtained pain relief. The posterolateral corner was reconstructed in combination with a valgus osteotomy to address the posterolateral rotatory instability. The follow-up assessment at two years after the last surgery showed no symptoms, maintenance of limb alignment and no evidence of joint degeneration.

Clinical, Functional, and Morphological Evaluations of Posterior Cruciate Ligament Reconstruction With Remnant Preservation: Minimum 2-Year Follow-up

BACKGROUND

Numerous posterior cruciate ligament (PCL) reconstruction techniques have evolved and have revealed satisfactory outcomes; however, the optimal operative method for PCL reconstruction remains controversial.

HYPOTHESIS

Transtibial PCL reconstruction with a remnant preservation technique would result in successful clinical, radiological, functional, and morphological outcomes. In addition, it was hypothesized that the results of combined PCL and posterolateral corner (PLC) reconstruction would be comparable with those of isolated PCL reconstruction.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 168 patients who underwent arthroscopic PCL reconstruction with or without reconstruction of the PLC between March 2006 and June 2011 were retrospectively reviewed. Ninety-two patients who met the inclusion criteria were enrolled, and 47 of 92 patients who underwent combined PCL and PLC reconstruction were evaluated as a subgroup. The PLC was reconstructed using the single fibular sling method. The patients were assessed by means of the Lysholm score, International Knee Documentation Committee (IKDC) subjective knee score, and Tegner activity score. Stability was evaluated using a KT-2000 arthrometer and Telos device. Proprioception was assessed using the Biodex System. Follow-up magnetic resonance imaging (MRI) was performed in 34 patients, and second-look arthroscopic surgery was conducted in 36 patients.

RESULTS

The minimum follow-up duration was 24 months in all patients. Clinical outcomes and posterior instability improved significantly. The mean Lysholm score improved from 56.7 ± 7.1 to 89.3 ± 7.3, the mean IKDC subjective knee score improved from 53.3 ± 9.6 to 86.2 ± 6.1, and the mean Tegner activity score was 2.5 ± 0.8 preoperatively and 5.1 ± 1.3 postoperatively (all P < .001). The mean side-to-side difference on posterior stress radiography with the Telos device improved significantly, decreasing from 12.1 ± 2.5 mm to 2.7 ± 1.3 mm (P < .001). The mean side-to-side difference on varus stress radiography was reduced from 5.9 ± 0.8 mm preoperatively to 1.3 ± 1.0 mm after combined PCL and PLC reconstruction (P < .001). Postoperative proprioception recovered to a level similar to that of the uninvolved side, and MRI and second-look arthroscopic surgery showed a high rate of complete healing and synovialization in patients who underwent either isolated PCL reconstruction or combined PLC and PCL reconstruction.

CONCLUSION

Transtibial PCL reconstruction with remnant preservation resulted in satisfactory clinical, functional, radiological, and morphological outcomes. The results of combined posterolateral rotatory instability were comparable with those for isolated PCL reconstruction with adequate PLC reconstruction.

Management of Combined Anterior Cruciate Ligament-Posterolateral Corner Tears: A Systematic Review

BACKGROUND

A consensus on the treatment of combined anterior cruciate ligament (ACL) and posterolateral corner (PLC) injuries is still lacking.

PURPOSE

To review the available literature on the management of these combined lesions to investigate the influence that injuries of knee posterolateral structures play in the outcome of an ACL lesion.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A comprehensive search was performed on PubMed, Medline, CINAHL, Cochrane, Embase, and Google Scholar databases using various combinations of the following keywords: "posterolateral corner," "plc," "posterolateral instability," "posterolateral injury," "anterior cruciate ligament," and "acl."

RESULTS

A total of 6 studies involving 95 patients were included. For those with PLC lesions, 14 patients were treated nonoperatively, 9 underwent an early anatomic repair, while the remaining 72 underwent a reconstruction. In all 95 patients, an ACL reconstruction was performed. Sixty-seven of the 72 patients who underwent a PLC reconstruction were assessed for anteroposterior laxity, with a mean side-to-side difference of 1.5 ± 1.1 mm. Evaluated by the objective International Knee Documentation Committee (IKDC) Knee Form, 88% of the patients who underwent a PLC reconstruction were graded as good/excellent (A/B). The 9 patients who underwent an early surgical repair of the PLC lesion were evaluated by means of the objective IKDC score, with 3 patients (33%) graded as good/excellent (A/B), and by means of a clinical evaluation, with 5 of 9 patients (56%) graded as 1+ for varus laxity. For the 14 patients who were managed nonoperatively for PLC injuries, the only clinical score available was the subjective IKDC score, with a mean value of 80.5 (87.8 for the 6 patients with type A PLC injuries and 75.0 for type B PLC injuries).

CONCLUSION

There is a paucity of literature focused on the management of combined ACL and PLC injuries. Combined ACL and PLC reconstruction seems to be the most effective approach to these combined lesions. However, future work is needed to explore the long-term outcome of the different treatment options.

Femoral radiographic landmarks for popliteus tendon reconstruction and repair: a new method of reference

BACKGROUND

Although the popliteus muscle-tendon complex is one of the most important structures in controlling posterolateral rotatory stability of the knee, not much literature has been reported concerning the use of femoral radiographic landmarks of the popliteus tendon in repair and reconstruction.

HYPOTHESIS

By using standardized radiographic techniques, the femoral insertion of the popliteus tendon could be more precisely determined by the Blumensaat line than by the extension line of the posterior cortex.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Ten fresh-frozen human knees were dissected, and the popliteus tendon was exposed. After identification of the femoral insertion site of the popliteus tendon, the insertion's center was indicated with a radiographic marker. True lateral radiographs of the distal femur were taken, and the digital radiographic images were analyzed by 2 independent observers.

RESULTS

The femoral insertion site of the popliteus tendon was found to be a mean 47.5% ± 5.2% across the width of the femoral condyle, 60.7% ± 7.8% along the perpendicular bisector of the Blumensaat line, 0.3 ± 1.7 mm posterior to the extension line of the posterior femoral cortex, and 20.5 ± 3.8 mm distal to the perpendicular line at the Blumensaat point. The variance from the mean point by using the Blumensaat line as a reference was significantly smaller than by using the extension line of the posterior cortex (mean, 2.6 vs 3.6 mm; P = .044).

CONCLUSION

A reproducible anatomic and radiographic reference point for the femoral insertion of the popliteus tendon can be determined using standardized radiographic techniques and can be more precisely determined by the Blumensaat line compared with the extension line of the posterior femoral cortex.

CLINICAL RELEVANCE

This radiographic information provides an adjunctive tool for preoperative, intraoperative, and postoperative assessments of surgical repair and reconstruction of the popliteus tendon.

In vitro comparison of popliteus tendon and popliteofibular ligament reconstruction in an external rotation injury model of the knee: a cadaveric study evaluated by a navigation system

BACKGROUND

In posterolateral corner (PLC) injuries in which the lateral collateral ligament (LCL) is intact, there is controversy about whether reconstructing the popliteus tendon (POP), the popliteofibular ligament (PFL), or both structures (POP + PFL) is required to restore normal external tibial rotation.

HYPOTHESIS

Three reconstruction techniques, POP, PFL, and POP + PFL, are able to restore external tibial rotation to normal.

STUDY DESIGN

Controlled laboratory study.

METHODS

Six nonpaired human knees were tested under the following states: POP and PFL intact and sectioned. The 3 different surgical techniques were used to reconstruct the sectioned structures, and the knees were retested. Each knee was subjected to a 5-N·m external rotation torque and tested at 0°, 30°, 45°, 60°, 90°, and 120° of flexion. A navigation system was used to measure motion changes of the tibia with respect to the femur.

RESULTS

There were small but significant increases in external rotation after sectioning both the POP and PFL. Sectioning of either one of these structures alone produced smaller increases that were not significant. After comparing all of the tested reconstructed states to the intact state, there were significant differences at knee flexion angles from 30° to 90°. The PFL procedure restored external tibial rotation without significant differences compared with the intact knee at 30° to 90° of flexion. The POP and POP + PFL techniques significantly overconstrained external tibial rotation at all tested angles.

CONCLUSION

In an LCL-intact PLC injury model, the POP and PFL function as a unit in resisting external rotation. All surgical procedures described and tested were able to reduce the increased external rotational laxity found in the sectioned state. The PFL reconstruction technique was able to restore external rotation to near normal. However, the techniques involving POP reconstruction overconstrained external rotation during laxity testing.

Clinical outcomes for reconstruction of the posterolateral corner and posterior cruciate ligament in injuries with mild grade 2 or less posterior translation: comparison with isolated posterolateral corner reconstruction

BACKGROUND

There have been no previous studies showing clinical outcomes according to treatment options of posterior cruciate ligament (PCL) injury with mild grade 2 or less posterior translation (<7 mm) combined with posterolateral rotatory instability.

PURPOSE

To compare the clinical outcomes of posterolateral corner (PLC) reconstruction with or without simultaneous PCL reconstruction in PCL injuries with mild posterior translation.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 46 patients with a PCL injury with mild posterior translation combined with posterolateral rotatory instability were retrospectively reviewed. Twenty-two patients had undergone isolated PLC reconstruction (group A), and 24 patients had undergone simultaneous reconstruction of the PCL and PLC (group B). Each patient was assessed for knee instability with the dial test at 30° and 90° as well as with varus and posterior stress radiography and were evaluated with the Lysholm knee score and International Knee Documentation Committee (IKDC) subjective and objective grading.

RESULTS

In all cases, the minimum follow-up period was 24 months. At the final follow-up evaluation, no significant side-to-side difference was found on varus stress radiography (group A, 1.55 ± 0.78 mm vs group B, 1.35 ± 1.00 mm; P = .458) or the dial test (at 30°: group A, 4.00° ± 1.83° vs group B, 4.04° ± 1.30°; P = .929; at 90°: group A, 3.64° ± 1.18° vs group B, 3.67° ± 1.37°; P = .937). However, group B showed a significant improvement compared with group A on posterior stress radiography (group A, 0.16 ± 0.44 mm vs group B, -1.44 ± 0.74 mm; P < .001), Lysholm knee score (group A, 18.36 ± 8.73 vs group B, 23.42 ± 7.44; P = .040), IKDC subjective score (group A, 25.51 ± 7.11 vs group B, 33.08 ± 5.89; P < .001), and IKDC objective score (group A preoperatively: grade C = 19 patients, grade D = 3; group B preoperatively: grade C = 20, grade D = 4; group A postoperatively: grade B = 11, grade C = 11; group B postoperatively: grade A = 12, grade B = 9, grade C = 3) (P < .001).

CONCLUSION

Simultaneous reconstruction of the PCL and PLC is recommended when addressing PCL injuries with mild grade 2 or less posterior translation combined with posterolateral rotary instability.

Posterolateral corner reconstruction using the single fibular sling method for posterolateral rotatory instability of the knee

BACKGROUND

Recently, posterolateral corner (PLC) reconstruction techniques have been developed based on an anatomic study of cadaveric dissections. However, the best operative method for various anatomic reconstructions remains controversial.

HYPOTHESIS

The anatomic single fibular sling method for PLC reconstruction would be sufficiently strong to control posterolateral rotatory instability without an additional tibial sling.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

This retrospective cohort study analyzed 60 knees in 60 patients who underwent anatomic PLC reconstruction using the single fibular sling method with a tibialis anterior allograft, with a minimum follow-up period of 2 years. Ninety percent of the patients had concomitant reconstruction of one or both cruciate ligaments. Preoperative and postoperative dial test, varus stress test, and subjective clinical outcomes including Lysholm score, International Knee Documentation Committee (IKDC) subjective scores, and stress radiographs, including varus and posterior stress, were compared. In addition, intraoperative arthroscopic findings were analyzed.

RESULTS

The mean length of clinical follow-up was 35.6 months (range, 24-65 months). Forty-two (70%) patients showed no rotational instability postoperatively. Varus laxity improved, with 96.7% of the patients assessed as grade 0 or 1. The mean side-to-side difference in varus stress test was reduced from 2.32 ± 1.33 mm preoperatively to 0.37 ± 1.48 mm postoperatively. Posterior stress radiography in combined posterior cruciate ligament reconstruction showed a mean posterior tibial translation of 14.7 ± 2.83 mm preoperatively and 4.06 ± 1.40 mm at final follow-up. The Lysholm and IKDC subjective scores improved from 52 ± 6.7 to 87.7 ± 12.3 and from 44.8 ± 6.3 to 77.6 ± 14.2 (P < .001), respectively. There were no significant differences in clinical outcome or varus laxity between isolated PLC and combined injuries.

CONCLUSION

Anatomic PLC reconstruction using a single fibular sling method is an effective and relatively simple procedure for most patients with posterolateral rotatory instability, with the exception of those with severe multiple injuries.

Popliteus bypass and popliteofibular ligament reconstructions reduce posterior tibial translations and forces in a posterior cruciate ligament graft

PURPOSE

To measure the abilities of popliteus tendon (POP) and popliteofibular ligament (PFL) graft reconstructions to limit posterior tibial translations and alter forces in a PCL graft reconstruction after posterior cruciate ligament (PCL) and lateral collateral ligament (LCL) reconstruction.

METHODS

Fifteen fresh frozen cadaveric knees underwent anterior-posterior (AP) laxity testing with 200 N of applied anterior and posterior tibial force. Forces in the native PCL were recorded during passive extension from 120 degrees to 0 degrees with an applied 100-N posterior tibial force. The popliteus tendon was released at its femoral origin, the PFL and LCL were cut, and the PCL was sectioned, creating a combined grade 3 PCL and posterolateral corner injury. The PCL was reconstructed with a single-bundle inlay graft tensioned to restore intact knee laxity to within 1 mm at 90 degrees , and the LCL was reconstructed with an anatomically placed graft. Testing was repeated with POP and PFL posterolateral reconstructions in addition to the PCL and LCL reconstructions.

RESULTS

PCL + LCL grafts alone matched intact knee laxities between 20 degrees and 90 degrees of flexion; mean laxity was 3.5 mm greater than intact at 0 degrees and 2.2 mm greater at 10 degrees. The addition of a POP reconstruction to PCL + LCL reconstructions significantly reduced AP laxities from -2.4 mm (0 degrees flexion) to -1.4 mm (90 degrees flexion). Mean laxities with POP and PFL grafts were not significantly different from the intact knee or from each other. Mean PCL graft forces with the PCL + LCL reconstructions alone were not significantly different than those with the native PCL. Mean PCL graft forces with POP and PFL reconstructions were not significantly different from each other; both means were significantly less than those for the PCL + LCL reconstructions alone at flexion angles greater than 55 degrees.

CONCLUSIONS

After PCL and LCL reconstruction, the popliteus bypass and popliteofibular ligament reconstructions not only eliminated excessive posterior laxity and returned the knee to a normal laxity profile but also resulted in substantial decreases in PCL graft forces.

CLINICAL RELEVANCE

These results provide further rationale for reconstructing torn posterolateral structures with a grade 3 posterolateral injury in combination with a PCL reconstruction.