Marco Nitri

An In Vitro Robotic Assessment of the Anterolateral Ligament, Part 1 Secondary Role of the Anterolateral Ligament in the Setting of an Anterior Cruciate Ligament Injury

Background: Recent investigations have described the structural and functional behavior of the anterolateral ligament (ALL) of the knee through pull-apart and isolated sectioning studies. However, the secondary stabilizing role of the ALL in the setting of a complete anterior cruciate ligament (ACL) tear has not been fully defined for common simulated clinical examinations, such as the pivot-shift, anterior drawer, and internal rotation tests. Hypothesis: Combined sectioning of the ALL and ACL would lead to increased internal rotation and increased axial plane translation during a pivot-shift test when compared with isolated sectioning of the ACL. Study Design: Controlled laboratory study. Methods: Ten fresh-frozen human cadaveric knees were subjected to a simulated pivot-shift test with coupled 10-N·m valgus and 5-N·m internal rotation torques from 0° to 60° of knee flexion and a 5-N·m internal rotation torque and an 88-N anterior tibial load, both from 0° to 120° of knee flexion via a 6 degrees of freedom robotic system. Kinematic changes were measured and compared with the intact state for isolated sectioning of the ACL and combined sectioning of the ACL and ALL. Results: Combined sectioning of the ACL and ALL resulted in a significant increase in axial plane tibial translation during a simulated pivot shift at 0°, 15°, 30°, and 60° of knee flexion and a significant increase in internal rotation at 0°, 15°, 30°, 45°, 60°, 75°, 90°, 105°, and 120° when compared with the intact and ACL-deficient states. Based on the model results, ALL sectioning resulted in an additional 2.1 mm (95% CI, 1.4-2.9 mm; P < .001) of axial plane translation during the pivot shift when compared with ACL-only sectioning, when pooling evidence over all flexion angles. Likewise, when subjected to IR torque, the ACL+ALL-deficient state resulted in an additional 3.2° of internal rotation (95% CI, 2.4°-4.1°; P < .001) versus the intact state, and the additional sectioning of the ALL increased internal rotation by 2.7° (95% CI, 1.8°-3.6°; P < .001) versus the ACL-deficient state. Conclusion: The results of this study confirm the ALL as an important lateral knee structure that provides rotatory stability to the knee. Specifically, the ALL was a significant secondary stabilizer throughout flexion during an applied internal rotation torque and simulated pivot-shift test in the context of an ACL-deficient knee. Clinical Relevance: Residual internal rotation and a positive pivot shift after ACL reconstruction may be attributed to ALL injury. For these patients, surgical treatment of an ALL tear may be considered.

An In Vitro Robotic Assessment of the Anterolateral Ligament, Part 2 Anterolateral Ligament Reconstruction Combined With Anterior Cruciate Ligament Reconstruction

Background: Recent biomechanical studies have demonstrated that an extra-articular lateral knee structure, most recently referred to as the anterolateral ligament (ALL), contributes to overall rotational stability of the knee. However, the effect of anatomic ALL reconstruction (ALLR) in the setting of anterior cruciate ligament (ACL) reconstruction (ACLR) has not been biomechanically investigated or validated. Purpose/Hypothesis: The purpose of this study was to investigate the biomechanical function of anatomic ALLR in the setting of a combined ACL and ALL injury. More specifically, this investigation focused on the effect of ALLR on resultant rotatory stability when performed in combination with concomitant ACLR. It was hypothesized that ALLR would significantly reduce internal rotation and axial plane translation laxity during a simulated pivot-shift test compared with isolated ACLR. Study Design: Controlled laboratory study. Methods: Ten fresh-frozen cadaveric knees were evaluated with a 6 degrees of freedom robotic system. Knee kinematics were evaluated with simulated clinical examinations including a simulated pivot-shift test consisting of coupled 10-N·m valgus and 5-N·m internal rotation torques, a 5-N·m internal rotation torque, and an 88-N anterior tibial load. Kinematic differences between ACLR with an intact ALL, ACLR with ALLR, and ACLR with a deficient ALL were compared with the intact state. Single-bundle ACLR tunnels and ALLR tunnels were placed anatomically according to previous quantitative anatomic attachment descriptions. Results: Combined anatomic ALLR and ACLR significantly improved the rotatory stability of the knee compared with isolated ACLR in the face of a concurrent ALL deficiency. During a simulated pivot-shift test, ALLR significantly reduced internal rotation and axial plane tibial translation when compared with ACLR with an ALL deficiency. Isolated ACLR for the treatment of a combined ACL and ALL injury was not able to restore stability of the knee, resulting in a significant increase in residual internal rotation laxity. ALLR did not affect anterior tibial translation; no significant differences were observed between the varying ALL conditions with ACLR except between ACLR with an intact ALL and ACLR with a deficient ALL at 0° of flexion. Conclusion: In the face of a combined ACL and ALL deficiency, concurrent ACLR and ALLR significantly improved the rotatory stability of the knee compared with solely reconstructing the ACL. Clinical Relevance: Significant increases in residual internal rotation and laxity during the pivot-shift test may exist in both acute and chronic settings of an ACL deficiency and in patients treated with isolated ACLR for a combined ACL and ALL deficiency. For this subset of patients, surgical treatment of the ALL, in addition to ACLR, should be considered to restore knee stability.

Meniscal Allograft Transplantation Without Bone Plugs A 3-Year Minimum Follow-up Study

Background: Meniscal allograft transplantation is a viable option for subtotally meniscectomized and totally meniscectomized symptomatic patients and potentially results in pain relief and increased function. Hypothesis: The use of a single tibial tunnel arthroscopic technique without bone plugs will reduce symptoms (pain) and improve knee function at a minimum 3-year follow-up. Study Design: Case series; Level of evidence, 4. Methods: Thirty-two meniscal transplantations (16 medial, 16 lateral; 23 men, 9 women) were prospectively evaluated at a minimum of 36 months (mean, 40.4 ± 6.90 months; range, 36-66 months) after surgery. The average age at the time of surgery was 35.6 ± 10.3 years (range, 15-55 years). The transplantation was performed using an arthroscopic bone plug–free technique with a single tibial tunnel plus “all-inside” meniscal sutures. The anterior meniscal horn was sutured to the capsule. Follow-up included a visual analog scale (VAS) score for knee pain and subjective and objective International Knee Documentation Committee (IKDC), Lysholm, Tegner, and SF-36 scores. All patients underwent radiographic and magnetic resonance imaging (MRI) evaluation of the involved knee before the surgery and at the final follow-up. The MRI outcomes were evaluated with the modified Yulish score. Results: Regarding clinical evaluation, there was a significant improvement in scores at follow-up compared with preoperatively: the VAS score decreased from 70.6 ± 21.7 to 25.2 ± 22.7 (P < .0001), the SF-36 physical component score increased from 37.31 ± 7.2 to 49.69 ± 8.3 (P < .0001), the SF-36 mental component score increased from 49.69 ± 10.8 to 53.53 ± 7.5 (P = .0032), the Tegner activity score increased from 3 (range, 3-5) to 5 (range, 3-6) (P < .0121), the Lysholm score increased from 59.78 ± 18.25 to 84.84 ± 14.4 (P < .0001), the subjective IKDC score increased from 47.44 ± 20.60 to 77.20 ± 15.57 (P < .0001), and the objective IKDC score changed from 1 A, 21 B, 6 C, and 4 D to 22 A, 9 B, and 1 C (P < .0001). No significant difference was found in this study between patients who received medial allografts and patients who received lateral allografts. There was no significant difference between outcomes of patients with isolated and combined procedures. The MRI findings showed 69% extruded allografts (8 medial and 14 lateral). In detail, we found 50% of the medial allografts and 87% of the lateral allografts extruded. No significant difference in clinical outcomes and modified Yulish score was found between patients with extruded allografts and with in situ allografts. The MRI results also showed a significant decrease of the modified Yulish score from baseline to 3-year minimum follow-up (P < .0001 for femur and P < .0001 for tibia). Only one patient underwent arthroscopic selective meniscectomy because of a medial posterior horn retear of the graft. One patient developed lack of flexion and underwent an arthroscopic arthrolysis. These 2 patients did not draw benefit from allografting and therefore were considered failures. In all remaining cases (94%), meniscal allograft transplantation was able to reduce symptoms (pain measured by VAS) and improve knee function (as measured by IKDC and Lysholm scores). Conclusion: This study found that a single tibial tunnel arthroscopic technique without bone plugs for meniscal allograft transplantation significantly reduced pain and improved knee function in 94% of patients at a minimum 3-year follow-up.

Can the pivot-shift be eliminated by anatomic double-bundle anterior cruciate ligament reconstruction?

PurposeTo assess the ability of anatomic double-bundle anterior cruciate ligament reconstruction in eliminating the pivot-shift phenomenon when identified by a quantitative measuring system (computer navigation or magnetic resonance imaging).MethodsLiterature review. Medline, Google Scholar and Cochrane Reviews computerized databases research using the keywords “pivot-shift,” “anterior cruciate ligament reconstruction” and “double bundle.” Twelve (7 in vitro and 5 in vivo) studies met the inclusion criteria.ResultsThere was a wide variation in the absolute value of translation and rotation measured after anatomic double-bundle anterior cruciate ligament reconstruction. There were also differences in fixation methods, pivot-shift execution conditions, applied stresses during the pivot-shift, calculation methods and reference systems utilized by measurement systems.ConclusionsThe double-bundle reconstruction was shown to over-constrain the knee with respect to the intact value, especially closer to knee extension. This review demonstrated that anatomic double-bundle anterior cruciate ligament reconstruction is able to eliminate pathological translations and rotations during the pivot-shift phenomenon, as identified by quantitative measurement systems.Level of evidenceReview of Level III studies, Level III.

A Novel Repair Method for Radial Tears of the Medial Meniscus Biomechanical Comparison of Transtibial 2-Tunnel and Double Horizontal Mattress Suture Techniques Under Cyclic Loading

Background: Complete radial tears of the medial meniscus have been reported to be functionally similar to a total meniscectomy. At present, there is no consensus on an ideal technique for repair of radial midbody tears of the medial meniscus. Prior attempts at repair with double horizontal mattress suture techniques have led to a reportedly high rate of incomplete healing or healing in a nonanatomic (gapped) position, which compromises the ability of the meniscus to withstand hoop stresses. Hypothesis: A newly proposed 2-tunnel radial meniscal repair method will result in decreased gapping and increased ultimate failure loads compared with the double horizontal mattress suture repair technique under cyclic loading. Study Design: Controlled laboratory study. Methods: Ten matched pairs of male human cadaveric knees (average age, 58.6 years; range, 48-66 years) were used. A complete radial medial meniscal tear was made at the junction of the posterior one-third and middle third of the meniscus. One knee underwent a horizontal mattress inside-out repair, while the contralateral knee underwent a radial meniscal repair entailing the same technique with a concurrent novel 2-tunnel repair. Specimens were potted and mounted on a universal testing machine. Each specimen was cyclically loaded 1000 times with loads between 5 and 20 N before experiencing a load to failure. Gap distances at the tear site and failure load were measured. Results: The 2-tunnel repairs exhibited a significantly stronger ultimate failure load (median, 196 N; range, 163-212 N) than did the double horizontal mattress suture repairs (median, 106 N; range, 63-229 N) (P = .004). In addition, the 2-tunnel repairs demonstrated decreased gapping at all testing states (P < .05) with a final measured gapping of 1.7 mm and 4.1 mm after 1000 cycles for the 2-tunnel and double horizontal mattress suture repairs, respectively. Conclusion: The 2-tunnel repairs displayed significantly less gapping distance after cyclic loading and had significantly stronger ultimate failure loads compared with the double horizontal mattress suture repairs. Clinical Relevance: Complete radial tears of the medial meniscus significantly decrease the ability of the meniscus to dissipate tibiofemoral loads, predisposing patients to early osteoarthritis. Improving the ability to repair medial meniscal radial tears in a way that withstands cyclic loads and heals in an anatomic position could significantly improve patient healing rates and result in improved preservation of the articular cartilage of the medial compartment of the knee. The 2-tunnel repair may be a more reliable and stronger repair option for midbody radial tears of the medial meniscus. Clinical studies are warranted to further evaluate these repairs.

Anatomic and Nonanatomic Double-Bundle Anterior Cruciate Ligament Reconstruction An In Vivo Kinematic Analysis

Background: There have been no direct in vivo biomechanical comparisons performed between an anatomic double-bundle (ADB) and a nonanatomic double-bundle (NADB) anterior cruciate ligament (ACL) reconstruction. Hypothesis: There are differences in kinematic outcomes between ADB and NADB ACL reconstruction techniques. Study Design: Controlled laboratory study. Methods: Twenty-six consecutive patients (mean age, 30 years; range, 18-32 years; 23 men, 3 women; 17 right knees, 9 left knees) with an isolated ACL injury were included in the study. The first 13 consecutive patients underwent NADB reconstruction (combination of a single-bundle and an over-the-top reconstruction), and the following 13 consecutive patients were treated with an ADB approach (using 2 tibial tunnels and 2 femoral tunnels placed in the center of the native femoral and tibial insertion sites). Grafts were pretensioned at 80 N and secured with cortical fixation systems under manual maximum force tension. Standard clinical laxity and pivot-shift tests were quantified at time zero before and after ACL reconstruction by means of a surgical navigation system dedicated to kinematic assessment; displacement of the medial and lateral compartments during the tests was also analyzed. Results: The ADB-reconstructed knees showed a larger preoperative-to-postoperative difference in anterior-posterior tibial plateau displacement of the medial and lateral compartments when compared with the NADB-reconstructed knees during the internal-external rotation test at 30° of flexion (P < .050). No other significant differences in laxity or pivot-shift values were noted. The mean surgical time for ADB reconstruction was significantly higher than that for NABD reconstruction (62 ± 13 and 43 ± 10 minutes, respectively; P < .0001). Conclusion: Results showed a greater anterior-posterior translation of both compartments during the rotational passive laxity test in the ADB reconstruction group or overconstraint caused by the NADB technique. The 2 analyzed double-bundle ACL reconstructions did not show any significant quantitative difference in isolated anterior-posterior laxity and pivot-shift phenomenon at time zero. Clinical Relevance: Nonanatomic double-bundle ACL reconstruction can control anterior-posterior laxity and the pivot-shift phenomenon as well as ABD ACL reconstruction.

Anatomic Double-Bundle Posterior Cruciate Ligament Reconstruction

The posterior cruciate ligament (PCL) is known to be the main posterior stabilizer of the knee. Anatomic single-bundle PCL reconstruction, focusing on reconstruction of the larger anterolateral bundle, is the most commonly performed procedure. Because of the residual posterior and rotational tibial instability after the single-bundle procedure and the inability to restore the normal knee kinematics, an anatomic double-bundle PCL reconstruction has been proposed in an effort to re-create the native PCL footprint more closely and to restore normal knee kinematics. We detail our technique for an anatomic double-bundle PCL reconstruction using Achilles and anterior tibialis tendon allografts.

Arthroscopic intra- and extra-articular anterior cruciate ligament reconstruction with gracilis and semitendinosus tendons: a review

The purposes of this paper are to summarize the concepts relating to the use of a combined intra-articular and extra-articular reconstructive procedure in the arthroscopic treatment of a torn ACL and to review several operative techniques utilizing gracilis and semitendinosus tendons that are currently in use to treat this instability. The highly satisfactory results obtained over the time show that a combination of intra- and extra-articular procedures for ACL reconstruction is a valid surgical option.

Does the type of graft affect the outcome of revision anterior cruciate ligament reconstruction?: a meta-analysis of 32 studies

Aims Our aim was to perform a meta‐analysis of the outcomes of revision anterior cruciate ligament (ACL) reconstruction, comparing the use of different types of graft. Materials and Methods A search was performed of Medline and Pubmed using the terms “Anterior Cruciate Ligament” and “ACL” combined with “revision”, “re‐operation” and “failure”. Only studies that reported the outcome at a minimum follow‐up of two years were included. Two authors reviewed the papers, and outcomes were subdivided into autograft and allograft. Autograft was subdivided into hamstring (HS) and bone‐patellar tendon‐bone (BPTB). Subjective and objective outcome measures were analysed and odds ratios with confidence intervals were calculated. Results A total of 32 studies met the inclusion criteria. Five studies used HS autografts, eight reported using BPTB autografts, two used quadriceps tendon autografts and eight used various types. Seven studies reported using allografts, while the two remaining used both BPTB autografts and allografts. Overall, 1192 patients with a mean age of 28.7 years (22.5 to 39) and a mean follow‐up of 5.4 years (2.0 to 9.6) were treated with autografts, while 269 patients with a mean age of 28.4 years (25 to 34.6) and a mean follow‐up of 4.0 years (2.3 to 6.0) were treated with allografts. Regarding allografts, irradiation with 2.5 mrad was used in two studies while the graft was not irradiated in the seven remaining studies. Reconstructions following the use of autografts had better outcomes than those using allograft with respect to laxity, measured by KT‐1000/2000 (MEDmetric Corporation) and the rates of complications and re‐operations. Those following the use of allografts had better mean Lysholm and Tegner activity scores compared with autografts. If irradiated allografts were excluded from the analysis, outcomes no longer differed between the use of autografts and allografts. Comparing the types of autograft, all outcomes were similar except for HS grafts which had better International Knee Documentation Committee scores compared with BPTB grafts. Conclusion Autografts had better outcomes than allografts in revision ACL reconstruction, with lower post‐operative laxity and rates of complications and re‐operations. However, after excluding irradiated allografts, outcomes were similar between autografts and allografts. Overall, the choice of graft at revision ACL reconstruction should be on an individual basis considering, for instance, the preferred technique of the surgeon, whether a combined reconstruction is required, the type of graft that was previously used, whether the tunnels are enlarged and the availability of allograft.

Synthetic meniscal scaffolds

Arthroscopic partial meniscectomies showed better clinical results with respect to complete meniscus removal, but at long-term follow-up a substantial number of patients suffer the effect of a lost meniscus cartilage. It is extremely important to preserve the meniscus as much as possible to avoid degenerative knee joint progression. During the 1980s Stone, Steadman and Rodkey developed a new collagen I scaffold to replace meniscus in the case of irreparable major tears: the CMI (Collagen Meniscus Implant). After 13 years of good results in implanting ReGen, Medial CMI, in 2006 we started a postmarketing study to evaluate the efficacy and effectiveness of an equivalent meniscal scaffold specifically designed to repair the lateral meniscal defect (ReGen, Lateral CMI). In this study, we describe indications for the implantation of a CMI device, the evolution of the surgical technique (from in-out arthroscopic suturing technique to all-inside arthroscopic scaffold implantation) in these 13 years of experience, and a short report of our clinical results.