Bone Plug Technique Research Articles

Accelerated versus Standard Rehabilitation after Meniscus Allograft Transplantation in the Knee.

Meniscus allograft transplantation (MAT) is a proven treatment option for patients with symptomatic irreparable meniscus deficiency. When patients are adherent to prescribed postoperative restriction and rehabilitation protocols, outcomes after MAT are considered good to excellent. However, nonadherence to standard protocols is common and can be associated with undesirable outcomes and patient dissatisfaction. Based on demonstrated safety for early weight-bearing following MAT in conjunction with significant advances in graft preservation and surgical techniques, our joint preservation center implemented a shift in practice toward accelerated weight-bearing following MAT and designed this study to test the hypothesis that accelerated rehabilitation would be associated with superior adherence, patient-reported outcomes, and patient satisfaction, without diminishing patient safety, when compared with standard rehabilitation. Patients were included for analyses when they had undergone fresh or fresh-frozen MAT using a double bone plug technique for treatment of medial or lateral meniscus deficiency and had at least 1-year treatment outcomes recorded. The results of this study revealed that patients who were prescribed accelerated rehabilitation after MAT were significantly more adherent than patients who were prescribed standard rehabilitation and reported statistically significant and clinically meaningful improvements in knee pain and function for at least 1-year following MAT, whereas those in the standard cohort did not. While not statistically different, treatment failure rate was lower in the accelerated rehabilitation cohort when compared with the standard rehabilitation cohort (11 vs. 29%). Importantly, initial outcomes for revision MAT were associated with short-term success in all the patients who opted for this option in the study population. These data suggest that accelerated weight-bearing after MAT is safe, promotes patient adherence, and is associated with statistically significant and clinically meaningful improvements in patient-reported knee pain and function at early and mid-term follow-up.

Medial Meniscal Allograft Transplantation: The Bone Plug Technique

Background: The medial and lateral menisci act as shock absorbers for the knee joint by converting and redistributing axial load into circumferential hoop stresses. Disruptions of these hoop stresses occur in the setting of meniscal deficiency and lead to long-term degenerative changes. Therefore, maintaining the distinctive composition and organization of the menisci is essential. In selective cases of meniscal deficiency, meniscus allograft transplantation can be a valuable treatment option. Indications: Meniscus transplantation should be considered in patients with symptomatic meniscal deficiency, without the presence of advanced degenerative pathologies, who have failed all conservative treatments. Technique description: We can divide the surgery into 4 steps: (1) graft preparation, (2) arthroscopic joint preparation, (3) allograft attachment preparation, and (4) graft fixation. Results: Meniscus allograft transplantation yields good to excellent results in up to 85% of cases. Improvement of pain and knee function occurs in approximately 70% of the patients at 10 years. The associated complications are mainly joint stiffness, early osteoarthritis, and incomplete healing accompanied by graft failure. Graft failure is the most feared complication, yet shows good results over the midterm. Conclusion: The bone plug technique we have shown here is a hybrid approach combining soft tissue and bone fixation techniques. It provides synergistic advantages with good osseous integration and is minimally invasive through arthroscopy without true arthrotomy. In our experience, this approach elegantly eases the complexity of this demanding surgery while yielding excellent results for patients. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Assessment of Anatomic Restoration and Clinical Outcomes Between Medial and Lateral Meniscal Allograft Transplantation.

Background:Proper anatomic restoration is an important consideration for meniscal allograft transplantation (MAT), even with the different anatomica characteristics between the medial meniscus and lateral meniscus.Purpose/Hypothesis:The purpose of this study was to assess the accuracy of anatomic restoration in medial and lateral MAT (MMAT and LMAT) procedures and to compare their outcomes. We hypothesized that (1) the anatomic differences between the medial and lateral menisci will mean a less accurate anatomic restoration for MMAT and (2) clinical outcomes after MMAT will be inferior compared with LMAT.Study Design:Cohort study; Level of evidence, 3.Methods:We retrospectively evaluated 20 patients who underwent MMAT using the bone plug technique and 21 patients who underwent LMAT using the keyhole technique at a single institution from July 2014 to June 2019. Demographic data, previous surgeries, and concomitant procedures were recorded, as were lower limb alignment and osteoarthritis grade on radiographs. Using preoperative and follow-up magnetic resonance imaging, the meniscal position, rotation, extrusion, and intrameniscal signal intensity were evaluated. Clinical outcomes were evaluated using the International Knee Documentation Committee and Lysholm scores.Results:The mean follow-up was 41.15 ± 18.86 and 45.43 ± 21.32 months for the MMAT and LMAT patients, respectively. Concomitant procedures were performed in 90% of MMATs and 15% of LMATs. There was no significant difference between the native and postoperative root positions after LMAT; however, for MMAT, the position of the anterior root was located significantly posteriorly (P = .002) and medially (P = .007) compared with preoperatively. In addition, the allograft medial meniscus was restored in a more internally rotated position (P = .029). MMATs also exhibited significantly increased meniscal extrusion compared with LMATs (posterior horn, P < .001; midbody, P = .027; anterior horn, P = .006). However, there was no significant difference between the 2 groups at final follow-up in intrameniscal signal intensity or clinical scores.Conclusion:LMAT showed higher accuracy than MMAT in restoring meniscal position and rotation, and there was less meniscal extrusion. However, clinical scores improved after both LMAT and MMAT compared with preoperative values, and midterm clinical outcomes were similar. The small anatomical errors seen in the MMAT technique were not clinically relevant at midterm follow-up.

Six Percent Incidence of Graft-Tunnel Mismatch in Anatomic Anterior Cruciate Ligament Reconstruction Using Bone-Patella Tendon-Bone Autograft and Anteromedial Portal Drilling

PurposeThe purpose of this study was to determine the incidence of graft-tunnel mismatch (GTM) when performing anatomic anterior cruciate ligament reconstruction (ACLR) using bone-patella tendon-bone (BPTB) grafts and anteromedial portal drilling.MethodsBeginning in November 2018, 100 consecutive patients who underwent ACLR by two sports fellowship-trained, orthopedic surgeons using BPTB autograft and anteromedial portal drilling were prospectively identified. The BPTB graft dimensions and the femoral tunnel distance, tibial tunnel distance, intra-articular distance, and total distance were measured. Surgeons determined the depth and angle of tunnels based on the patella tendon graft length dimensions in each case. After passage of the graft, the distance from the distal graft tip to the tibial cortex aperture was measured. GTM was defined as the need for additional measures to obtain satisfactory tibial graft fixation (<15–20 mm of bone fixation).ResultsThe incidence of mismatch was 6/100 (6%). Five cases involved the graft being too long, with the tibial bone plug protruding excessively from the tibial tunnel—4/5 had a patella tendon length ≥ 50 mm. Three cases were managed with femoral tunnel recession, and two were treated with a free bone plug technique. One patient with a patella tendon length of 35 mm had a graft that was too short, with the tibial bone plug recessed in the tibial tunnel. Of patients whose tibial tunnel distance was within 5 mm of the patella tendon length, only 1/46 (2%) patients had mismatch, whereas 5/54 (9%) of patients who had >5 mm difference had mismatch.ConclusionsThe incidence of graft-tunnel mismatch after anatomic ACLR using BTPB and anteromedial portal drilling in this study is 6%. To limit the occurrence of GTM where the graft is too long, surgeons should drill tibial tunnel distances within 5 mm of the patella tendon length.Clinical RelevanceThe results of this study provide surgeons with a technique of limiting graft tunnel mismatch when performing ACLR using BPTB and anteromedial portal drilling.

Bone-Tendon-Autograft Anterior Cruciate Ligament Reconstruction: A New Anterior Cruciate Ligament Graft Option

The bone-tendon-bone (BTB) autograft is widely used for anterior cruciate ligament (ACL) reconstruction. However, the primary disadvantages of this technique include postoperative kneeling pain, the risk of perioperative patellar fracture, and graft-tunnel mismatch. Therefore, a single bone plug technique for ACL reconstructions was developed to mitigate the disadvantages of the BTB technique. To differentiate this graft, we have coined the term BTA, for bone-tendon-autograft. The middle third of the patellar tendon is used with a typical width of 10 to 11 mm. A standard tibial tubercle bone plug is harvested. The length of the patellar tendon and graft construct is then measured. If the tendon is >45 mm and the construct at least 70 mm, then we proceed with the BTA technique. At the inferior pole of the patella, electrocautery is used to harvest the tendon from the patella. The advantages of this technique include faster graft harvest and preparation. Obviating the patellar bone plug harvest should eliminate the risk of perioperative patellar fracture and theoretically will mitigate donor site morbidity and kneeling pain, 2 of the most commonly cited complications of the use of BTB autografts for ACL reconstruction. In conclusion, the BTA technique is a reliable technique for ACL reconstruction.

Bone-Plug Versus Soft Tissue Fixation of Medial Meniscal Allograft Transplants: A Biomechanical Study

Background: It is controversial whether soft tissue fixation only and bone-plug techniques for medial meniscal allograft transplantation provide equivalent fixation and restoration of load distribution. Prior studies on this topic did not re-create the clinical situation with use of size-, side-, and compartment-matched meniscal transplants. Hypothesis: Both techniques will provide equivalent fixation of the meniscal transplant and restore load distribution and contact pressures similar to those of the native knee. Study Design: Controlled laboratory study. Methods: Nine fresh-frozen human cadaveric knees underwent mean contact pressure, mean contact area, and peak contact pressure evaluation in 4 medial meniscal testing conditions (native, total meniscectomy, bone-plug fixation, and soft tissue fixation) at 3 flexion angles (0°, 30°, and 60°) using Tekscan sensors under a 700-N axial load. Results: Medial meniscectomy resulted in significantly decreased contact area and increased contact pressure compared with the native condition at all flexion angles (P < .0001). Compared with the native state, soft tissue fixation demonstrated significantly higher mean contact pressure and lower mean contact area at 0° and 30° of flexion (P < .05), while bone-plug fixation showed no significant difference. There was no significant difference in peak contact pressure between study conditions. Conclusion: Total medial meniscectomy leads to significantly worsened load distribution within the knee. Medial meniscal allograft transplantation can restore load parameters close to those of the native condition. The bone-plug technique demonstrated improved tibiofemoral contact pressures compared with soft tissue fixation. Clinical Relevance: Medial meniscal allograft transplantation with bone-plug fixation is a viable option to restore biomechanics in patients with meniscal deficiency.

Comparative Matched-Pair Analysis of Keyhole Bone-Plug Technique Versus Arthroscopic-Assisted Pullout Suture Technique for Lateral Meniscal Allograft Transplantation

To compare the clinical outcomes and meniscal extrusion measured by magnetic resonance imaging (MRI) between the keyhole bone-plug technique and arthroscopic-assisted pullout suture technique in lateral meniscal allograft transplantation (MAT). Between October 2009 and February 2015, patients who underwent lateral MAT were retrospectively reviewed. The inclusion criteria were patients with symptomatic knees that had undergone total or subtotal meniscectomy who were treated with lateral MAT with a minimum follow-up period of 2years. We excluded 13 patients with anterior cruciate ligament injury to the ipsilateral knee and 6 patients with combined cartilage procedures. In addition, we excluded 19 patients because they did not undergo follow-up MRI and 13 patients who did not undergo more than 2years of follow-up. Thirty-seven patients who underwent lateral MAT with the keyhole bone-plug technique were identified and assigned to group A. Forty-five patients who underwent lateral MAT with the arthroscopic-assisted pullout suture technique (group B) were then matched by age, body mass index, and time from previous meniscectomy to lateral MAT. Clinical outcome assessments included preoperative and postoperative subjective International Knee Documentation Committee (IKDC), Tegner, and Lysholm scores and the visual analog scale (VAS) score for pain evaluation. MRI was used to assess meniscal extrusion. The mean follow-up period was 35.8 ± 6.5months (range, 24-65months) in group A and 34.6 ± 6.2months (range, 24-55months) in group B. Significant improvements in the VAS pain score, subjective IKDC score, Tegner score, and Lysholm score after lateral MAT were found (P < .001), and there were no significant differences between the 2 groups at final follow-up (VAS score, 1.4 ± 0.8 in group A and 1.2 ± 1.0 in group B [P= .164]; subjective IKDC score, 72.9 ± 8.1 in group A and 74.2 ± 7.3 in group B [P= .427]; Tegner activity score, 4.0±0.9 in group A and 4.1 ± 0.8 in group B [P= .374]; and Lysholm score, 75.5 ± 10.6 in group A and 76.2 ± 11.8 in group B [P= .786]). On MRI, the meniscal extrusion extent was 3.1 ± 0.9mm in group A and 2.9 ± 0.8mm in group B (P= .223), and the relative percentages of extrusion were 27.0% ± 3.9% and 26.1% ± 4.2%, respectively (P= .273). Compared with the keyhole bone-plug technique, the arthroscopic-assisted pullout suture technique in lateral MAT showed comparable clinical and MRI results at short-term follow-up. Level IV, case series with intragroup comparisons.

Clinical and radiologic outcomes after a modified bone plug technique with anatomical meniscal root reinsertion for meniscal allograft transplantation and a minimum 18-month follow-up

ObjectiveTo evaluate the clinical and radiologic outcomes of meniscal allograft transplantation (MAT) using a modified bone plug technique.MethodsWe conducted a retrospective single-center study of 73 patients who underwent MAT between January 2007 and December 2013. The International Knee Documentation Committee (IKDC) score, Lysholm score, Tegner score, visual analogue scale (VAS), and physical examinations were retrospectively reviewed to measure clinical outcomes after MAT, and questionnaires regarding activity and factors were analyzed. Magnetic resonance imaging (MRI) was used to assess the cartilage status and meniscal extrusion.ResultsThe mean follow-up was 37 months for 61 patients (65 knees), and 12 patients were lost to follow-up. The mean meniscal extrusion was 3.39 ± 0.90 mm, the relative percentage of extrusion (RPE) was 34.82% ± 12.71%, and arthrosis progression was observed in 8 of 61 cases (13.1%). The mean results for VAS, IKDC, and Lysholm scores were significantly improved after MAT (P < 0.05), but there were no significant differences in the range of motion or Tegner score (P > 0.05). Thirty-eight (62.3%) patients were able to return to their previous level of activity, and 23 (37.7%) patients reached a mean 76.7% of the previous level of activity. Of the 23 patients reporting a decrease in activity, 10 reported a fear of reinjury as the primary factor limiting activity. The patient satisfaction rate in the study was 78.7%.ConclusionOur modified bone plug method with anatomical meniscal root reinsertion was an effective surgical method, and the majority of active patients with meniscal disorders returned to preinjury levels of activity.

Arthroscopic Medial Meniscal Allograft Transplantation with Modified Bone Plug Technique

The meniscal allograft transplantation (MAT) has been reported to be an effective treatment in terms of pain relief and functional improvement in symptomatic meniscus-deficient knee. The medial MAT is usually performed with the bone plug technique or soft tissue fixation for root fixation. We describe medial MAT with modified bone plug technique that permits easy passage of posterior bone plugs and facilitates bone-to-bone healing. With this method, an anterior bone plug with a long cylindrical shape is prepared, and the posterior bone plug is prepared with a flat bone shell containing a cancellous portion. This modified technique facilitates graft passage as well as bone-to-bone healing.

Does Medial Meniscal Allograft Transplantation With the Bone-Plug Technique Restore the Anatomic Location of the Native Medial Meniscus?

Background: Previous work has shown the importance of restoring the normal structure of the native meniscus with meniscal allograft transplantation. Purpose/Hypothesis: The purpose of this study was to compare the anatomic positions of the anterior horn and posterior horn between the preoperative medial meniscus and the postoperative meniscal allograft after medial meniscal allograft transplantation with the bone-plug technique. The hypothesis was that the bone-plug technique could restore the preoperative structure of the native medial meniscus. Study Design: Case series; Level of evidence, 4. Methods: Between December 1999 and December 2013, a total of 59 patients (49 male, 10 female) underwent medial meniscal allograft transplantation by use of the bone-plug technique. The anatomic positions of both horns in the native medial meniscus and in the meniscal allograft were measured via MRI. The percentage reference method was used to measure the locations of both horns. Results: On coronal MRI, the mean absolute distance of the posterior horn from the lateral border of the tibial plateau changed from 45.2 ± 3.3 to 48.1 ± 4.2 mm (P < .05), and the percentage distance of the posterior horn changed from 59.6% to 63.0% (P < .05). On sagittal MRI, the mean absolute distance of the posterior horn from the anterior reference point changed from 40.3 ± 3.0 to 42.0 ± 3.5 mm (P < .05), and the mean percentage distance of the posterior horn changed from 76.5% to 79.4% (P <.05). On coronal MRI, the mean absolute distance of the anterior horn from the lateral border of the tibial plateau changed from 41.3 ± 4.2 to 48.5 ± 5.6 mm (P < .05), and the mean percentage distance of the anterior horn changed from 54.5% to 63.8% (P < .05). On sagittal MRI, the mean absolute distance of the anterior horn from the anterior reference point changed from 5.5 ± 1.0 to 9.9 ± 2.9 mm (P < .05), and the mean percentage distance of the anterior horn changed from 10.6% to 19.0% (P < .05). Conclusion: Despite attempts to place the meniscal allograft in the same position as the native meniscus, the anatomic locations of both horns were shifted posteromedially compared with those of the native medial meniscus. There were significant differences, attributed to several limitations in the bone-plug technique, between the preoperative and postoperative values of both horns. However, the posterior horn showed a location change of <5 mm, on average, in both the coronal and sagittal planes, whereas the anterior horn showed a location change of ≥5 mm in the coronal plane but <5 mm in the sagittal plane.

Influence of Different Tibial Fixation Techniques on Initial Stability in Single-Stage Anterior Cruciate Ligament Revision With Confluent Tibial Tunnels: A Biomechanical Laboratory Study

To kinematically and biomechanically compare 4 different types of tibial tunnel management in single-stage anterior cruciate ligament (ACL) revision reconstruction with the control: primary ACL reconstruction using a robotic-based knee testing setup. Porcine knees and flexor tendons were used. One hundred specimens were randomly assigned to 5 testing groups: (1) open tibial tunnel, (2) bone plug technique, (3) biodegradable interference screw, (4) dilatation technique, and (5) primary ACL reconstruction. A robotic/universal force-moment sensor testing system was used to simulate the KT-1000 (MEDmetric, San Diego, CA) and pivot-shift tests. Cyclic loading and load-to-failure testing were performed. Anterior tibial translation increased significantly with all of the techniques compared with the intact ACL (P < .05). In the simulated KT-1000 test, groups 2 and 3 achieved results equal to those of primary ACL reconstruction (P > .05). The open tunnel and dilated tunnel techniques showed significantly greater anterior tibial translation (P < .05). The results of the simulated pivot-shift test were in accordance with those of the KT-1000 test. No significant differences could be observed regarding stiffness or maximum load to failure. However, elongation was significantly lower in the primary ACL reconstruction group compared with groups 1 and 3 (P= .02 and P= .03, respectively). Filling an incomplete and incorrect tibial tunnel with a press-fit bone plug or a biodegradable interference screw in a standardized laboratory situation provided initial biomechanical properties and knee stability comparable with those of primary ACL reconstruction. In contrast, the dilatation technique or leaving the malplaced tunnel open did not restore knee kinematics adequately in this model. Backup extracortical fixation should be considered because the load to failure depends on the extracortical fixation when an undersized interference screw is used for aperture fixation. Our biomechanical results could help orthopaedic surgeons to optimize the results of primary ACL revision with incomplete, incorrect tunnel placement.

Biomechanical Comparison Between Bashti Bone Plug Technique and Biodegradable Screw for Fixation of Grafts in Ligament surgery.

Ligament reconstruction is a common procedure in orthopedic surgery. Although several popular techniques are currently in use, new methods are proposed for secure fixation of the tendon graft into the bone tunnel. We sought to introduce our new technique of Bashti bone plug for fixation of soft tissue graft in anterior cruciate ligament (ACL) reconstruction and to compare its biomechanical features with conventional absorbable interference screw technique in a bovine model. Twenty pairs of bovine knees were harvested after death. Soft tissue was removed and the Achilles tendon was harvested to be used as an ACL graft. It was secured into the bone tunnel on the tibial side via two different methods: Bashti Bone Plug technique and conventional screw method. Biomechanical strength was measured using 200 N and 300 N cyclic loading on the graft. Pull out strength was also tested until the graft fails. No graft failure was observed after 200 N and 300 N cyclic loading in either fixation methods. When testing for pull out failure, 21 tendons (53%) were torn and 19 tendons (48%) slipped out. No fixation failure occurred, which did not reveal a significant difference between the bone plug or interference screw group (P=0.11). The mean pull out force until failure of the graft was 496±66 N in the screw group and 503±67 N in the bone plug group (P=0.76). Our suggested fixation technique of Bashti bone plug is a native, cheap, and feasible method that provides comparable biomechanical strength with interference screw when soft tissue fixation was attempted in bovine model.

Avoiding Graft-Tunnel Length Mismatch in Anterior Cruciate Ligament Reconstruction: The Single–Bone Plug Technique

Anterior cruciate ligament reconstruction, using autogenous bone–patellar tendon–bone (BTB) as a graft material, is commonly performed in the setting of anterior cruciate ligament insufficiency. Although bone–patellar tendon–bone autograft has an extensive track record, showing excellent clinical results, donor-site morbidity and graft-tunnel mismatch can still be problematic for a subset of patients. In the setting of a tendon graft that is too long, adequate interference screw fixation cannot be obtained, typically resulting in a tibial-sided bone plug that achieves less than 15 to 20 mm of bone in the distal tibial tunnel. We present an easy and effective technique for avoiding the graft-tunnel mismatch problems that commonly occur in patients who have an excessively long patellar tendons. This technique involves a simple preoperative planning algorithm that ultimately results in a single tibial-sided plug harvest. Bony interference fixation is then obtained on the femoral side and soft-tissue fixation on the tibial side. This technique allows for satisfactory graft fixation while avoiding the donor-site morbidity associated with patellar bone plug harvest.

Endoscopic procurement of allograft tympano-ossicular systems: valuable to replace the Schuknecht bone plug technique?

Recently, our group demonstrated the technical feasibility of allograft tympano-ossicular systems (ATOS) procurement directly through the external auditory canal by using a rigid endoscope. This novel technique has several advantages compared to the traditional transcranial Schuknecht bone plug technique: it avoids contact with the dura mater, it is less time-consuming and it doesn't require a thorough reconstruction of the donor. In our tissue bank, we are currently transitioning from the transcranial procurement technique to the endoscopic procurement technique. The learning curve to master the endoscopic technique is steep but our preliminary results suggest that the percentage of good quality endoscopically procured ATOS is at least similar to the percentage of good quality transcranially procured ATOS dissected from the temporal bone plug. Additionally, the number of donations has increased significantly. By avoiding contact with the dura mater and therefore eliminating the risk of potential prion disease transmission, this technical evolution in procurement technique might allow dedicated tissue banks to (re-)introduce ATOS procurement and implantation.

Medial Meniscus Allograft Transplantation Using a Modified Bone Plug Technique: Clinical, Radiologic, and Arthroscopic Results

To determine clinical, radiologic, and arthroscopic results of our meniscus allograft transplantation (MAT) by use of modified bone plug technique, which permits easy passage of the allograft by reducing the size of the posterior bone plug. From December 2004 to December 2008, 22 consecutive patients (20 men and 2 women) with a mean age of 35.9 years underwent medial MAT with the modified bone plug method. The Lysholm score and International Knee Documentation Committee subjective knee score were documented. Joint space narrowing and Kellgren-Lawrence grade changes were evaluated on radiographs, and graft healing status, arthrosis changes in cartilage, and meniscal extrusion were investigated by magnetic resonance imaging (MRI). The mean follow-up was 24.9 months. The mean Lysholm score improved significantly, from 68.2 to 89.7 (P = .002). The International Knee Documentation Committee subjective knee score improved significantly, from 60.3 to 85.4 (P = .003). Joint space narrowing was insignificant, and arthrosis progression was observed in 3 of 22 cases (13.6%) on radiographs. On MRI, complete healing of the grafts was observed in 18 cases (100%), 15 cases (83.3%), and 17 cases (94.4%) at the anterior root, posterior root, and meniscal rim, respectively. Mean meniscal extrusion was 4.35 ± 1.76 mm, and arthrosis progression was observed in 4 of 18 cases (22.2%). During second-look arthroscopy, complete healing of the grafts was observed in 11 cases (100%), 9 cases (81.8%), and 10 cases (90.9%) at the anterior root, posterior root, and meniscal rim, respectively. Cartilage degeneration was advanced in 4 cases (36.4%). No significant correlations were found between meniscal extrusion and other outcomes. Our modified bone plug method was an effective surgical method. MRI and second-look arthroscopic examinations showed sound evidence of graft healing. Meniscal extrusion was observed in most cases but was not correlated with other clinical and radiologic outcomes. Level IV, therapeutic case series.

Analysis of preliminary clinical results of meniscal allograft transplantation.

Objective The purpose of this study was to report the preliminary outcomes of a series of patients who had undergone allograft meniscus transplantation with a minimum 1-year follow-up. Methods From June 2006 to July 2008,19 consecutive patients underwent meniscus allograft transplantation. Of them, 18 cases were included in this study. There were nine males and nine females. The patients ranged from twenty-one to fifty-two years old, with an average age of 38 years.The injury of anterior eruciate ligament was found in 7patients. There were multiple injury of ligaments of knee and fracture of tibial plateau in 2 pa-tients and one patient. Surgical technique:16 menisci were transplanted using the double bone plug tech-nique, 2 lateral menisci wers fixed using the bone bridge technique. Variable meniscus repair techniques were used for suturing the graft menisci's tim to capsule.The injury of ligament could be repaired stably by a concomitant reconstructive procedure at the time of transplantation or a separate surgery. Results Eighteen patients were followed up. The follow-up time ranged from 16 to 41 months,with the mean of 26 months. The allogrates were assessed by second-look arthroscopy. It comfirmed that 16 cases were normal or nearly nor-mal and two (11%)failed which solved with meniscectomy. Postoperative stiff knee occured in one patient who required arthroscopic arthrolysis. One patient with meniscal cyst underwent conservative treatment. 15 patients were assessed by full subjective evaluation. The mean Lysholm scores had improved from 67 to 85. On IKDC evaluation, two patients were grade A and twelve were grade B, one were grade C. With regard to pain and satisfaction, the average VAS had improved from 6.2 to 2.1. Conclusion Arthrosocpic meniscus transplantation can achieve satisfied subjective and objective clinical outcomes with 89% survival rate over a mean follow-up period of 26 months. Key words: Menisci,tibial; Transplantation,homologous; Endoscopy

The Effects of Medial Meniscal Transplantation Techniques on Intra-Articular Contact Pressures

This study aimed to compare medial compartment contact pressures in knees treated with medial meniscal transplantation using either a bone plug or bone trough technique. Peak pressure, mean pressure, and contact area of the medial compartment were determined in 8 cadaveric specimens at 0 degrees and 30 degrees of flexion under a 1000-N load. Contact mechanics were measured for the intact knee, after meniscectomy, and after medial meniscal transplant with either a bone plug technique or a bone trough technique. Total medial meniscectomy resulted in decreased contact area, increased medial contact pressure, and increased medial peak contact pressure. When comparing meniscal transplant techniques at both 0 degrees and 30 degrees, no significant difference (P < 0.05) was noted regarding contact mechanics after transplantation. The bone trough technique shows similar contact mechanics to the double bone plug technique and maintains the natural hoop stress of the meniscus during medial meniscal transplantation.

Revision of Failed Lateral Meniscal Allograft Transplant

Meniscus allograft transplantation (MAT) is an acceptable procedure for the younger patient with a meniscus-deficient knee that has not yet developed advanced arthrosis. Numerous reports on good shortterm clinical outcomes are present in the literature; however, reports on failures and revision MAT are relatively scarce. We report a case of a failed lateral MATwith the slotted bone technique, revised with a bone plug technique. We also review the literature for failed MAT and analyze the mode of failure in this case.