An anterior cruciate ligament and medial collateral ligament tear in a skeletally immature patient: a new technique to augment primary repair of the medial collateral ligament and an allograft reconstruction of the anterior cruciate ligament

Surgical Treatment of Combined ACL PCL Medial Side Injuries

The multiple ligament knee injury involving the medial collateral ligament, anterior cruciate ligament, and posterior cruciate ligament is typically the result of a high-energy trauma or knee dislocation event. Optimal treatment strategies are debated, specifically in regard to timing of surgery, reconstruction/repair techniques, and postoperative protocols. This review details the stepwise treatment of these complex patients from diagnosis to postoperative rehabilitation and summarizes the current literature.

Mechanical and Microstructural Properties of Native Pediatric Posterior Cruciate and Collateral Ligaments

Background:

Although anterior cruciate ligament (ACL) tears have received the most attention, the medial collateral ligament (MCL) is thought to be the most commonly injured knee ligament overall. The lateral collateral ligament (LCL) and posterior collateral ligament (PCL) are less frequently compromised but can be involved in severe multiligament injuries. The paucity of information on the native properties of these ligaments in the pediatric population hinders the overall optimization of treatment for these injuries.

Purpose:

To characterize the mechanical and microstructural properties of pediatric MCLs, LCLs, and PCLs using a rare cadaveric cohort (mean age, 9.2 years).

Study Design:

Descriptive laboratory study.

Methods:

MCLs, LCLs, and PCLs were harvested from 5 fresh-frozen pediatric knee specimens (3 male, 2 female) and were subjected to a tensile loading protocol. A subset of contralateral tissues from a single donor was analyzed using bright-field, polarized light, and transmission electron microscopy to measure collagen fiber morphology.

Results:

The pediatric MCL exhibited values for ultimate stress (11.7 ± 6.7 MPa), ultimate strain (18.2% ± 6.8%), and the Young modulus (93.7 ± 56.5 MPa) that were similar to values for the LCL (11.4 ± 11.5 MPa, 27.7% ± 12.9%, and 64.4 ± 76.6 MPa, respectively). The PCL demonstrated decreased ultimate stress (4.2 ± 1.8 MPa), increased ultimate strain (28.8% ± 11.9%), and a decreased Young modulus (19.8 ± 10.4 MPa) when compared with the MCL and LCL. All 3 ligaments had similar mean crimp wavelengths (MCL, 32.8 ± 3.6 µm; LCL, 27.2 ± 3.5 µm; PCL, 25.8 ± 3.5 µm) and collagen fibril diameters (MCL, 88.0 ± 26.0 nm; LCL, 93.3 ± 34.6 nm; PCL, 90.9 ± 34.0 nm); however, the fibril distribution profiles exhibited different modalities.

Conclusion:

The pediatric MCL and LCL possessed similar mechanical properties, while the pediatric PCL was weaker but capable of withstanding higher amounts of strain. All 3 of these pediatric structures were weaker than what has been reported in studies with adult cohorts.

Clinical Relevance:

Results from this study can be considered preliminary mechanical and microstructural data for healthy pediatric collateral and posterior cruciate ligaments that can be used to guide further laboratory and clinical research.

Biomechanical comparison of fixation techniques for medial collateral ligament anatomical augmented repair

PURPOSE

Although the majority of medial collateral ligament (MCL) ruptures can be treated conservatively with good results, some injuries require operative treatment. Besides MCL reconstruction, anatomical augmented repair may be considered. This study was to assess biomechanical properties of different fixation techniques regarding elongation and ultimate load to failure.

METHODS

MCL anatomical augmented repair was simulated by fixation of porcine superficial digital flexor tendon grafts at porcine tibiae. Ten different fixation techniques were assessed. Fixation of the tendon graft was performed using 4.0-mm cancellous screws and either (1) 13.5-mm spiked polyether ketone (PEEK) washers; (2) 14-mm spiked washers; (3) 14-mm suture washers; (4) 14-mm customized washers; (5-8) combination of washers and No. 2 polyester sutures (FiberWire©); or using (9) single or (10) double 5.5-mm titanium suture anchors with No. 2 polyethylene sutures (Ultrabraid^®). Biomechanical analysis included pretensioning of the constructs at 20 N for 30 s following cyclic loading of 250 cycles between 20 and 100 N at 1 Hz for measurement of elongation. Additionally, ultimate failure load and failure mode analysis were performed.

RESULTS

Spiked PEEK washers secured with polyester sutures (5) yielded best biomechanical properties at time zero for both, elongation during cyclic loading (2.9 ± 0.7 mm) and ultimate failure load (469.8 ± 64.3 N).

CONCLUSIONS

These results suggest that spiked PEEK washers secured with polyester sutures are the most appropriate fixation technique for MCL anatomical augmented repair, thus providing best requirements to allow early knee mobilization and prevent secondary knee laxity.

Surgical Techniques for the Reconstruction of Medial Collateral Ligament and Posteromedial Corner Injuries of the Knee: A Systematic Review

PURPOSE

To systematically review reconstruction techniques of the medial collateral ligament (MCL) and associated medial structures of the knee (e.g., posterior oblique ligament).

METHODS

A systematic review of Medline/PubMed Database (1966 to November 2013), reference list scanning and citation searches of included articles, and manual searches of high-impact journals (2000 to July 2013) and conference proceedings (2009 to July 2013) were performed to identify publications describing MCL reconstruction techniques of the knee. Exclusion criteria included (1) MCL primary repair techniques or advancement procedures, (2) lack of clear description of MCL reconstruction technique, (3) animal models, (4) nonrelevant study design, (5) and foreign language articles without available translation.

RESULTS

After review of 4,600 references, 25 publications with 359 of 388 patients (92.5%) were isolated for analysis, including 18 single-bundle MCL and 10 double-bundle reconstruction techniques. Only 2 techniques were classified as anatomic reconstructions, and clinical and objective outcomes (n = 28; 100% <3 mm side-to-side difference [SSD]) were superior to those with nonanatomic reconstruction (n = 182; 79.1% <3 mm SSD) and tendon transfer techniques (n = 114; 52.6% <3 mm SSD).

CONCLUSIONS

This systematic review demonstrated that numerous medial reconstruction techniques have been used in the treatment of isolated and combined medial knee injuries in the existent literature. Many variations exist among reconstruction techniques and may differ by graft choices, method of fixation, number of bundles, tensioning protocol, and degree of anatomic restoration of medial and posteromedial corner knee restraints. Further studies are required to better ascertain the comparative clinical outcomes with anatomic, non-anatomic, and tendon transfer techniques for medial knee reconstruction.

LEVEL OF EVIDENCE

Level IV, systematic review of level IV studies and surgical techniques.

Anteromedial rotatory laxity

This paper describes anteromedial rotatory laxity of the knee joint. Combined instability of the superficial MCL and the structures of the posteromedial corner is the pathological background anteromedial rotatory laxity. Anteromedial rotatory instability is clinically characterized by anteromedial tibial plateau subluxation anterior to the corresponding femoral condyle. The anatomical and biomechanical background for anteromedial laxity is presented and related to the clinical evaluation, and treatment decision strategies are mentioned. A review of the clinical studies that address surgical treatment of anteromedial rotatory instability including surgical techniques and clinical outcomes is presented. Level of evidence V.

[Acute medial collateral ligament injuries of the knee: diagnostics and therapy]

The medial collateral ligament complex (MCL) is the most commonly damaged ligamentous stabilizer of the human knee. The diagnostic algorithm comprises patient history, clinical examination and magnetic resonance imaging (MRI). It is important to distinguish between incomplete and complete ruptures of the MCL. For adequate treatment the classification and exact knowledge about concomitant injuries are important. A nonoperative treatment of incomplete ruptures (grades I and II) is widely accepted and usually results in a good clinical outcome but the treatment of complete ruptures (grade III) is a subject of controversy. Complete intraligamentous ruptures with a correct approximation of the stumps and intact dorsomedial joint capsule can also be treated nonoperatively with good and excellent results. In contrast, ruptures close to the abutment and bony avulsions tend to heal better through operative treatment. Dehiscence or dislocation of the ligament stumps in MRI is an indication for operative treatment. In the context of a multiligamentous injury or complex instability, the majority of authors suggest an operative stabilization. As the treatment of chronic instability can be challenging, the initial and adequate treatment of acute ruptures is of great importance.

Superficial medial collateral ligament anatomic augmented repair versus anatomic reconstruction: an in vitro biomechanical analysis

BACKGROUND

When surgical intervention is required for a grade 3 superficial medial collateral ligament (sMCL) tear, there is no consensus on the optimal surgical treatment. Anatomic augmented repairs and anatomic reconstructions for treatment of grade 3 sMCL tears have not been biomechanically validated or compared.

HYPOTHESIS

Anatomic sMCL augmented repairs and anatomic sMCL reconstruction techniques will reproduce equivalent knee kinematics when compared with the intact state, while creating significant improvements in translational and rotational laxity compared with the sMCL sectioned state.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eighteen match-paired, fresh-frozen cadaveric knees (average age, 52.6 years; range, 40-59 years) were each used to test laxity of an intact sMCL, a deficient sMCL, and either an anatomic augmented repair or an anatomic reconstruction. Knees were biomechanically tested in a 6 degrees of freedom robotic system, which included valgus rotation, internal and external rotation, simulated pivot shift, and coupled anterior drawer with external rotation.

RESULTS

Anatomic augmented repairs and anatomic reconstructions had significantly less medial joint gapping than the sectioned state at all tested flexion angles and showed significant reductions in valgus rotation compared with the sectioned state at all flexion angles. No significant differences between the anatomic augmented repair and anatomic reconstruction were found for any test performed. Despite the similar behavior between the 2 reconstruction groups, neither technique was able to reproduce the intact state.

CONCLUSION

Anatomic sMCL augmented repairs and anatomic sMCL reconstructions were not significantly different when tested at time zero. Both the anatomic augmented repair and the anatomic reconstruction were able to improve knee stability and provide less than 2 mm of medial joint gapping at 0° and 20° of flexion.

CLINICAL SIGNIFICANCE

These results suggest that both an anatomic sMCL augmented repair and an anatomic sMCL reconstruction improve knee kinematics compared with a deficient sMCL and provide equivalent joint stability.

Treating anterior cruciate ligament tears in skeletally immature patients

PURPOSE

To systematically review the current evidence for conservative and surgical treatment of anterior cruciate ligament (ACL) tears in skeletally immature patients.

METHODS

A systematic search of PubMed, CINAHL, EMBASE, CCTR, and CDSR was performed for surgical and/or conservative treatment of complete ACL tears in immature individuals. Studies with less than six months of follow-up were excluded. Study quality was assessed and data were collected on clinical outcome, growth disturbance, and secondary joint damage.

RESULTS

We identified 48 studies meeting the inclusion criteria. Conservative treatment was found to result in poor clinical outcomes and a high incidence of secondary defects, including meniscal and cartilage injury. Surgical treatment had only very weak evidence for growth disturbance, yet strong evidence of good postoperative stability and function. No specific surgical treatment showed clearly superior outcomes, yet the studies using physeal-sparing techniques had no reported growth disturbances at all.

CONCLUSIONS

The current best evidence suggests that surgical stabilization should be considered the preferred treatment in immature patients with complete ACL tears. While physeal-sparing techniques are not associated with a risk of growth disturbance, transphyseal reconstruction is an alternative with a beneficial safety profile and a minimal risk of growth disturbance. Conservative treatment commonly leads to meniscal damage and cartilage destruction and should be considered a last resort.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II, III, and IV studies.

An in vitro analysis of an anatomical medial knee reconstruction

BACKGROUND

An anatomical medial knee reconstruction has not been described in the literature.

HYPOTHESIS

Knee stability and ligamentous load distribution would be restored to the native state with an anatomical medial knee reconstruction.

STUDY DESIGN

Controlled laboratory study.

METHODS

Ten nonpaired cadaveric knees were tested in the intact, superficial medial collateral ligament and posterior oblique ligament-sectioned, and anatomically reconstructed states. Each knee was tested at 0 degrees , 20 degrees , 30 degrees , 60 degrees , and 90 degrees of knee flexion with a 10-N.m valgus load, 5-N.m external and internal rotation torques, and 88-N anterior and posterior drawer loads. A 6 degrees of freedom electromagnetic motion tracking system measured angulation and displacement changes of the tibia with respect to the femur. Buckle transducers measured the loads on the intact and reconstructed proximal and distal divisions of the superficial medial collateral ligament and the posterior oblique ligament.

RESULTS

A significant increase was found in valgus angulation and external rotation after sectioning the medial knee structures at all tested knee flexion angles. This was restored after an anatomical medial knee reconstruction. The authors also found a significant increase in internal rotation at 0 degrees , 20 degrees , 30 degrees , and 60 degrees of knee flexion after sectioning the medial knee structures, which was restored after the reconstruction. A significant increase in anterior translation was observed after sectioning the medial knee structures at 20 degrees , 30 degrees , 60 degrees , and 90 degrees of knee flexion. This increase in anterior translation was restored following the reconstruction at 20 degrees and 30 degrees of knee flexion, but was not restored at 60 degrees and 90 degrees . A small, but significant, increase in posterior translation was found after sectioning the medial knee structures at 0 degrees and 30 degrees of knee flexion, but this was not restored after the reconstruction. Overall, there were no clinically important differences in observed load on the ligaments when comparing the intact with the reconstructed states for valgus, external and internal rotation, and anterior and posterior drawer loads. Conclusion An anatomical medial knee reconstruction restores near-normal stability to a knee with a complete superficial medial collateral ligament and posterior oblique ligament injury, while avoiding overconstraint of the reconstructed ligament grafts.

CLINICAL SIGNIFICANCE

This anatomical medial knee reconstruction technique provides native stability and ligament load distribution in patients with chronic or severe acute medial knee injuries.

Operative management of the medial collateral ligament in the multi-ligament injured knee: an evidence-based systematic review

While it is generally accepted that most partial and isolated medial collateral ligament (MCL) injuries can be treated non-operatively, ideal treatment of the MCL in multi-ligament knee injuries remains controversial. High failure rates with repair of the posterolateral corner in the multi-ligament injured knee have been recently reported, favoring reconstruction instead. The same maybe true for MCL injuries, however evidence-based treatment recommendations are lacking in the current orthopedic literature. The purpose of this study was to perform an evidence-based systematic review of the operative management (repair and/or reconstruction) of the MCL in the setting of multi-ligament knee injuries. A comprehensive search of MEDLINE and the Cochrane databases for all relevant articles published in English from 1978 to 2008 on the outcomes of surgical management (repair and/or reconstruction) of the MCL in the setting of combined ligament injuries was performed. Inclusion criteria included articles published in (1) English, (2) on human subjects, (3) between the years of 1978 and 2008, (4) had minimum 12-month follow-up, with a mean of at least 24 months, (5) on surgical management of MCL injuries, (6) associated with multi-ligament injuries (three or more ligaments) and/or knee dislocation, and (7) reported objective outcome data on the respective patient cohorts. Exclusion criteria consisted of technique papers, case reports, studies that included fractures associated with MCL injury and those that included pediatric patients. The review identified eight relevant studies. Five articles focused on MCL repair, while three articles focused on MCL reconstruction. No prospective studies compared MCL repair or reconstruction with non-operative treatment or directly compared MCL reconstruction with MCL repair. Currently there is a paucity of objective data on the outcomes regarding surgical management of MCL tears in the combined ligament injured knee. This systematic review demonstrated satisfactory results in both repair and reconstruction groups. Future objective outcome-based studies as well as comparative studies are needed to further evaluate the optimal treatment modality before evidence-based recommendations can be made. Therefore, individual treatment decisions for each patient should be based on the characteristics and nature of the injury.