Bone Plug Research Articles

Combined Medial Meniscus Allograft Transplantation and Open-Wedge High Tibial Osteotomy Using a Patient-Specific Instrumentation Guide

Despite technical advances in meniscus allograft transplantation, there remains a need to improve postoperative outcomes.1,2 The bone plugs technique using osseous fixation of the anterior and posterior roots has demonstrated increased stability and long-term survival. Recently, the importance of limb alignment has been demonstrated for this procedure. In case of malalignment, osteotomy is essential to improve the long-term viability of both meniscus allograft and cartilage. The recent introduction of patient-specific instrumentation has raised the possibility of making instrumentation specific to each patient achieving an optimal correction in a safe and reliable manner. This Technical Note describes the use of a combined medial meniscus allograft transplantation and open wedge high tibial osteotomy using a patient-specific instrumentation guide.

A Cost-Effective Novel Surgical Technique of Core Decompression with Bone Marrow Aspiration Concentrate: A Preliminary Cadaveric Study.

Core decompression supplemented by stem cell incorporation is an upcoming field of research in avascular necrosis of the femoral head. Plugging the canal to avoid loss of the concentrate injected has been recognized as a crucial step to improve the efficacy of the procedure. We describe a new surgical technique that results in native bone plug formation and eliminates the need for any additional blocker. This pilot study was performed on 4 cadaveric proximal femurs. The standard technique was used for core decompression and bone marrow aspirate concentrate (BMAC) injection. Additionally, two more tracts were drilled, superolateral, and inferomedial to the primary tract. No leakage of the radiopaque dye was observed from the entry point of the primary tract, ensuring its complete blockage in all 4 cadaveric proximal femurs. This was confirmed by sectioning the femur specimens which manifested bone plug formation at the confluence of the three tracts. Our technique is a unique and economical method of preventing leakage of BMAC through the entry point in the proximal femoral metaphysis. This may not only benefit patients but can also provide the groundwork for further research in this field.

Mosaicplasty With High Tibial Osteotomy for Knee Subchondral Insufficiency Fracture Had Better Magnetic Resonance Observation of Cartilage Repair Tissue Scores With Less Bone Marrow Edema and Better Plug Union and Less Plug Necrosis Compared With Mosaicplasty Alone

To determine the magnetic resonance imaging (MRI) findings after mosaicplasty (MOS) for knee subchondral insufficiency fracture (SIFK), and to analyze the relationship between MRI findings and clinical outcomes. We retrospectively reviewed the cases of consecutive patients who underwent MOS for SIFK with/without high tibial osteotomy (HTO) between January 1998 and December 2015. The MRI findings at 12 months after the surgery were assessed by the modified magnetic resonance observation of cartilage repair tissue (MOCART) score to determine the degree of bone marrow edema (BME), plug union, and plug necrosis. The clinical outcomes were assessed by Lysholm score to clarify the minimal clinically important difference (MCID) and patient acceptable symptom state analysis. In total, 58 patients (17 men and 41 women) were enrolled in this study. Among them, 30 knees were treated by MOS alone and 28 knees were treated by MOS with HTO. The MOCART scores of patients who received MOS alone were significantly lower in BME score (P= .0060), plug union score (P= .0216), and in plug necrosis score (P= .0326) than patients who received MOS with HTO. BME lesion was less likely to persist among elderly (odds ratio 1.20, P= .0248) and female (OR 41.8, P= .0118) patients. The MCID of Lysholm score was 6.6 in MOS alone and 8.4 in MOS with HTO cases, but there were no significant association between MRI findings and the postoperative Lysholm score. The MOS with HTO cases had better MOCART scores with less BME, better plug union, and less plug necrosis compared with MOS alone cases. Female and older patients had better resolution of BME, but there was no significant correlation between MRI findings and the postoperative Lysholm score. All cases in both groups showed improvement of Lysholm score exceeding MCID; thus, MOS may be effective as a joint preserving surgery for SIFK. Level IV, clinical case series.

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.

All-Inside Anterior Cruciate Ligament Reconstruction

AbstractAnterior cruciate ligament (ACL) reconstruction is one of the most commonly performed knee operations. An “all-inside” technique creates bone sockets for ACL graft passage, as opposed to more traditional full bone tunnels, and typically incorporates suspensory fixation instead of screw fixation to secure the graft. This technique may be indicated for any ACL reconstruction surgery, where adequate bone stock exists to drill sockets and to use cortical fixation. The technique may be used with all soft tissue, as well as bone plug ACL grafts and autograft hamstring or quadriceps tendon; most allograft tendon options may be performed with an all-inside technique. Advantages include anatomic tunnel/socket placement, decreased postoperative pain and swelling, minimal hardware, appropriate graft tensioning and retensioning, and circumferential graft to bone healing. Tips for successful all-inside surgery include matching graft diameter to socket diameter, drilling appropriate length sockets based on individual graft length, so as not to “bottom out” the graft and confirming cortical button fixation intraoperatively. Potential complications include graft-socket mismatch, full-tunnel reaming, and loss of cortical fixation. Multiple studies have shown the all-inside technique to have similar or superior biomechanical properties and clinical outcomes compared to the more traditional full-tunnel ACL reconstruction techniques.

Impact of beam-hardening corrections on proton relative stopping power estimates from single- and dual-energy CT.

A major contributing factor to proton range uncertainty is the conversion of computed tomography (CT) Hounsfield units (HU) to proton relative stopping power (RSP). This uncertainty is heightened in the presence of X‐ray beam‐hardening artifact (BHA), which has two manifestations: cupping and streaking, especially in and near bone tissue. This uncertainty can affect the accuracy of proton RSP calculation for treatment planning in proton radiotherapy. Dual‐energy CT (DECT) and iterative beam‐hardening correction (iBHC) both show promise in mitigating CT BHA. This present work attempts to analyze the relative robustness of iBHC and DECT techniques on both manifestations of BHA.The stoichiometric method for HU to RSP conversion was used for single‐energy CT (SECT) and DECT‐based monochromatic techniques using a tissue substitute phantom. Cupping BHA was simulated by measuring the HU of a bone substitute plug in wax/3D‐printed phantoms of increasing size. Streaking BHA was simulated by placing a solid water plug between two bone plugs in a wax phantom. Finally, the effect of varying calibration phantom size on RSP was calculated in an anthropomorphic head phantom.The RSP decreased −0.002 cm–1 as phantom size increased for SECT but remained largely constant when iBHC applied or with DECT techniques. The RSP varied a maximum of 2.60% in the presence of streaking BHA in SECT but was reduced to 1.40% with iBHC. For DECT techniques, the maximum difference was 2.40%, reduced to 0.6% with iBHC. Comparing calibration phantoms of 20‐ and 33‐cm diameter, maximum voxel differences of 5 mm in the water‐equivalent thickness were observed in the skull but reduced to 1.3 mm with iBHC. The DECT techniques excelled in mitigating cupping BHA, but streaking BHA still could be observed. The use of iBHC reduced RSP variation with BHA in both SECT and DECT techniques.

Anterior to Posterior Bone Plug Suture Tunnels Provide Optimal Biomechanics for Bone−Patellar Tendon−Bone Anterior Cruciate Ligament Graft

PurposeTo evaluate different bone−patellar tendon−bone (BPTB) plug suture configurations for pull through strength, stiffness, and elongation at failure in a biomechanical model of suspensory fixation.MethodsForty nonpaired, fresh-frozen human cadaveric BPTB allografts with an average age of 65.6 years were tested. Tensile testing was performed with the use of a custom-designed fixture mounted in a dynamic tensile testing machine. A preload of 90 N was applied to the graft and held for 5 minutes. Following this, a tensile load-to-failure test was performed. The ultimate failure load, elongation at failure, and mode of failure were recorded, and the resulting load–elongation curve was documented.ResultsThe drill tunnel through the cortical surface (anterior to posterior) was found to be significantly stronger than the drill tunnel through the cancellous surface (medial to lateral). There were no significant differences found when comparing the strength of the suture augmentation through the tendon and the drill tunnel alone (P = .13 among cancellous groups, P = .09 among cortical groups). The cortical drill tunnel with suture augmentation through the tendon showed significantly greater elongation values (13.7 ± 3.2) at failure when compared with either the cancellous or cortical drill tunnel only test groups (P = .0003 compared with cancellous alone, P = .009 when compared with cortical alone). Conclusions: The BPTB suture configuration with an anterior to posterior–directed suture tunnel without a suture through tendon augmentation provides the optimal strength and stiffness while minimizing graft elongation after fixation in a biomechanical model. This configuration is best for preventing suture pull through and failure when passing sutures through the BPTB plug.Clinical RelevanceThis study biomechanically evaluates the optimal suture configuration in the proximal bone plug for suspensory fixation in the setting of BPTB grafts.

Lateral meniscus allograft transplantation without bone plugs: technique and outcomes.

Once considered a non-fundamental structure, the menisci are now known to provide several functions within the knee, including protection of articular cartilage, load-bearing, shock absorption, joint stability, joint lubrification and joint congruity functions. Meniscal tears are one of the most common lesions in knee orthopedics, and partial or total meniscectomies are commonly performed procedures in orthopedic surgery. Despite meniscectomy is well recognized to lead improvement in clinical outcomes, it has been related to early onset knee osteoarthritis and joint degeneration which are associated with pain and functional limitations. Meniscal allograft transplantation has become a viable option for patients under 55 years old that have undergone total or near total meniscectomy and are in a painful state. This procedure can be performed using bone plugs or without bone plugs. In the bone plugs free technique allograft will be presented as a lateral meniscus with a portion of tibial plateau and is then introduced into the joint through an arthroscopic portal and fixed to the capsule with all-inside stitches. The most important aspect required to obtain good clinical results are graft size, anatomic placement and fixation, because extrusion is the most common complication related to meniscal transplantation. Although a lack of long-term follow-up (FU) studies, it has been demonstrated that lateral meniscus transplantation without bone plugs is a minimal invasive surgical procedure that improves the knee function, increases patient physical activity and reduces pain.

Poster 256: The "N+10 Rule" to Avoid Graft Tunnel Mismatch in Bone-Patellar Tendon-Bone Anterior Cruciate Ligament Reconstruction Using Independent Femoral Tunnel Drilling

Objectives: To determine the amount of tibial graft tunnel mismatch during application of the “N+10” rule in arthroscopic assisted anterior cruciate ligament (ACL) reconstruction with bone-patellar tendon-bone (BTB) graft using independent femoral tunnel drilling.To compare actual (measured) tibial tunnel length and desired (calculated) tibial tunnel length when using the “N+10” rule for independent femoral tunnel drilling. Methods:Twenty paired knees from 10 fresh frozen cadaveric specimens (5 female and 5 male specimens) underwent arthroscopic assisted bone-patellar tendon-bone ACL reconstruction using independent femoral tunnel drilling with either a hyperflexion accessory anteromedial portal (n=10) or flexible reamer technique (n=10). The prepared patellar tendon graft bone blocks were trimmed to 10 x 20mm for all specimens and the intertendinous distance (N) between the bone blocks was measured. The “N+10 Rule” was used to set the angle of the ACL tibial tunnel guide to the appropriate degree setting for drilling. The amount of excursion or recession of the tibial bone plug in relation to the anterior tibial cortical aperture was measured in both flexion and extension. A +/-6mm threshold was used to assess this strategy based on prior biomechanical aperture fixation studies. As a secondary outcome, the intraarticular distance (IAD) and the actual tibial tunnel length (TTL) were measured and compared to the planned TTL based on the equation: IAD + TTL = N + 20 (size of bone plug in millimeters)Results:The average BTB ACL intertendinous distance (N) was 47.5mm (SD =5.5mm). The average measured IAD was 27.2mm (SD=3.0mm). Using the “N+10 Rule”, the average mismatch of the tibial tunnel was 4.9mm (SD=3.6mm) and 3.8mm (SD=3.5mm) in flexion and extension, respectively. Both values fall within the +/- 6mm threshold. When comparing the actual measured tibial tunnel length (TTL) to the desired TTL, there was an average difference of 5.4mm (SD=3.9mm)Conclusions:The “N+10” rule resulted in an acceptable average mismatch in both flexion and extension using the threshold of +/- 6mm for 20 cadaveric knees. Measured actual TTL compared to the desired calculated TTL were acceptable 61% of the time using the same threshold. The “N+10” is a simple and effective intraoperative strategy for achieving desired tibial tunnel length to avoid excessive graft tunnel mismatch.Figure 1:Derived formula for calculating ideal tibial tunnel length (TTL) using intraarticular distance (IAD), and the known values of the intertendinous distance (N) and lengths of the bone blocks (20mm).Figure 2:Intraoperative photo of BTB ACL graft measuring intertendinous distance between the bone plugs (N=55mm). Following the "N+10" ruleFigure 3:Intraoperative photo of tibial ACL guide measurement of tibial tunnel length at 50mm with guide set to 65 degrees.Figure 4:Intraoperative photo of the ACL tibial tunnel guide positioned on the anatomic tibial footprint set to 65 degrees (N=55mm). Using this setting for the guide, the tibial tunnel measured 50mm as seen in the zoomed in photo, as per the formula.

Bone plug fixation in anterior cruciate ligament reconstruction: A clinical and radiological assessment of graft-tunnel integration

BackgroundThe decision regarding graft choice and fixation in anterior cruciate ligament (ACL) reconstruction remains controversial. Free cylindrical bone plugs have been used successfully as graft fixation method. However, some concerns continue to exist regarding how well these plugs integrate with the bony walls of the tunnel. The aim of this study was to assess osteo-integration of free cylindrical bone plugs and to evaluate its effect on the clinical outcomes of the procedure. MethodsFrom January 2015 to December 2017, 30 patients (21–40 years old) with torn ACL were operated on and followed up for 24 months after surgery. All patients were assessed clinically (International Knee Documentation Committee score (IKDC) and Tegner–Lysholm knee scoring system), instrumentally (KT 1000 and Rolimeter), and radiologically (X-ray, computed tomography and magnetic resonance imaging). Young active patients with torn ACL were included while those with previous ligamentous injury and/or surgery were excluded. ResultsAll bone grafts showed solid bone healing after 6 months of surgery; incorporation was ‘good to excellent’ (tibial side: 66.6%; femoral side: 86.6%). There was no correlation between age or time interval and graft incorporation. Positive correlation was shown between tibial and femoral graft incorporation within the same patient. Only one patient was abnormal in our final objective IKDC scores (graded C). The mean side-to-side difference with KT 1000 and Rolimeter was 1.9 and 1.8, respectively. ConclusionFree cylindrical bone plugs could be used safely for hamstring tendon graft fixation; it enhances graft tunnel integration within the first 6 months and yields comparable clinical outcomes whilst avoiding the potential hazards of foreign hardware implants.

Does the intramedullary femoral canal plug reduce blood loss during total knee arthroplasty?

IntroductionThe benefit of the femoral canal bone plug during total knee arthroplasty (TKA) in reducing blood loss has never been proven. The aim of this meta-analysis was to determine whether the femoral canal bone plug significantly reduces blood loss in primary TKA.MethodAll studies published before December 2021 were searched. The inclusion criteria were randomized controlled trials comparing blood loss between TKA with plugged and unplugged femoral intramedullary canal, respectively. The primary outcome was postoperative hemoglobin reduction.ResultsFive studies with a total of 717 patients (361 in the plugged group, 356 in the unplugged group) met the criteria for inclusion in the meta-analysis. The mean difference in hemoglobin level between the two groups was 0.92 g/dL, with significantly less hemoglobin reduction in the plugged group (95% confidence interval [CI] − 1.64 to − 0.21, p = 0.01). The patients in the plugged group also had a significantly lower risk of receiving a blood transfusion (risk ratio 0.58, 95% CI 0.47–0.73, p < 0.00001).ConclusionsThis meta-analysis demonstrates that using a femoral canal bone plug can significantly reduce blood loss and lower the risk ratio of blood transfusion in patients undergoing TKA.

The Hydration State of Bone Tissue Affects Contrast in Neutron Tomographic Images.

Neutron tomography has emerged as a promising imaging technique for specific applications in bone research. Neutrons have a strong interaction with hydrogen, which is abundant in biological tissues, and they can penetrate through dense materials such as metallic implants. However, in addition to long imaging times, two factors have led to challenges in running in situ mechanical characterization experiments on bone tissue using neutron tomography: 1) the high water content in specimens reduces the visibility of internal trabecular structures; 2) the mechanical properties of bone are dependent on the hydration state of the tissue, with drying being reported to cause increased stiffness and brittleness. This study investigates the possibility of improving image quality in terms of neutron transmission and contrast between material phases by drying and rehydrating in heavy water. Rat tibiae and trabecular bovine bone plugs were imaged with neutron tomography at different hydration states and mechanical testing of the bone plugs was carried out to assess effects of drying and rehydration on the mechanical properties of bone. From analysis of image histograms, it was found that drying reduced the contrast between bone and soft tissue, but the contrast was restored with rehydration. Contrast-to-noise ratios and line profiles revealed that the contrast between bone tissue and background was reduced with increasing rehydration duration but remained sufficient for identifying internal structures as long as no free liquid was present inside the specimen. The mechanical analysis indicated that the proposed fluid exchange protocol had no adverse effects on the mechanical properties.

Outcomes of Quadriceps Tendon Anterior Cruciate Ligament Reconstruction in Skeletally Immature Patients:2-Year Follow-Up

Background:The quadriceps tendon (QUAD) autograft has recently become an alternative to the hamstring tendon autograft that demonstrates superior preliminary outcomes in pediatric anterior cruciate ligament reconstruction (ACLR).Purpose:To evaluate 2-year clinical and patient-reported functional outcomes of primary ACLR with soft tissue QUAD autograft in skeletally immature patients.Methods:Consecutive skeletally immature patients who underwent ACLR with QUAD autograft were included. All cases utilized full thickness soft tissue QUAD autograft without a bone plug and were performed on patients with open growth plates. Preoperative demographic and surgical data were collected (Table 1). The ACLR technique was selected predicated upon skeletal age and included all-epiphyseal (AE) and complete transphyseal (CT). Patients were followed for a minimum of 24 months with successive clinical visits or contacted via telephone. Information regarding the return to sports and concomitant or subsequent surgical procedures was collected. KT-1000 was performed post-operatively, and Pediatric International Knee Documentation Committee (Pedi-IKDC) and HSS Functional Activity Brief Scale (HSS Pedi-FABS) scores were collected for each subject at their 2-year follow-up appointment.Results:The final cohort included of 60 consecutive adolescent patients aged 11.1 to 17.1 (13.9 ±1.2) with a minimum follow-up of 2 years. One patient was lost to follow-up. Prior to surgery, 86% of patients reported playing team sports including soccer, basketball, football and lacrosse, with soccer being the most popular one. 21 (35%) patients underwent AE and 39 (65%) underwent CT ACLR. Additionally, 35 (58%) underwent an a lateral extra-articular tenodesis procedure using the iliotibial band (ITB) with a modified Lemaire technique, and 5 (8%) patients underwent simultaneous implant mediated guided growth with a plate for structural genu valgum, both procedures were performed for non-modifiable risk factors as previously published for hamstring autograft ACLR. The rate of graft failure was 0%, and 10 patients had additional surgical procedures, of which 4 were concomitant removal of hardware for hemi-epiphysiodesis, 3 were contralateral ACLR, 3 were meniscal injuries that required surgical intervention and 2 were lysis of adhesions. The mean KT-1000 at 2-year follow-up was -0.36 ±0.75. The median Pedi-IKDC score was 87, and the median HSS-Pedi FABS score was 25. At 2 years after surgery, 90% patients reported returning to sports.Conclusion:This study reveals that QUAD autograft ACLR had a low failure rate when compared to previously reported studies of ACLR with hamstring autograft. Based on these results, we recommend this technique for skeletally immature patients undergoing ACLR.Table 1.Demographic and Surgical data of included knees.

Alternative for tibial fixation in Patellar Tendon ACL Reconstruction

Objective: Introduce an alternative for tibial fixation in Anterior Cruciate Ligament (ACL) with Patellar Tendon, in cases with long graft and a bone plug that stay outside the tibial tunnel and evaluate its results. Methods: From 2010 to 2020, 12 patients were submitted to a ACL reconstruction with a Bone-Patellar Tendon-Bone (BTB) graft using the anatomic technique. Starting with the femoral fixation, if the BTB graft is too long where the bone plug is outside the tibial tunnel, instead of cutting the graft, a cavity is dig in the tibia, distal to the tunnel entrance, and the bone plug is kept inside using a bone clip, followed by an interference screw in the tibial tunnel. With a minimum follow-up of 24 months, the patients knee stability was evaluated pre and post operatively. Results: The mean follow up was 29 months. All patients had a stable knee post operatively, with no complications. Conclusion: The ACL reconstruction using the proposed technique shown excellent results in short and long term, regarding knee stability. We believe that the proposed method is better than just cutting out the bone plug.

Arthroscopic Remplissage Using Knotless, All-Suture Anchors

Glenohumeral bone loss is a significant risk factor for recurrent instability after shoulder dislocation. The Hill-Sachs lesion is an osseous defect of the posterior humeral head that is commonly recognized after anterior shoulder dislocation. Several procedures exist to address humeral-sided bone loss, including soft tissue filling procedures, osteoarticular allografts, bone plugs, rotation osteotomies, and humeral head replacements. However, among the most common of these procedures is the arthroscopic remplissage. This technique involves capsulotenodesis of the posterior shoulder capsule and infraspinatus tendon into a Hill-Sachs lesion. Previously described techniques use knotted suture anchors. In this report, we describe a modified technique for remplissage using knotless, all-suture anchors to perform capsulotenodesis of a Hill-Sachs lesion. Benefits of this technique include a single skin incision, improved bone preservation, and easier facilitation of revision surgery if required.

Lateral Meniscus Allograft Transplantation in a Skeletally Immature Patient

Background: Lateral meniscus deficiency in young patients typically results from irreparable lateral meniscus tears, often associated with discoid meniscus. Such cases present a challenging clinical scenario given the known natural history of meniscus deficiency leading to degenerative lateral knee compartment changes. Managing this problem in a skeletally immature patient presents additional clinical and surgical considerations. Indications: Lateral meniscus allograft transplantation (LMAT) is indicated in patients with prior total or subtotal lateral meniscectomy resulting from irreparable lateral meniscus tears, with the goal of providing chondroprotection to the lateral compartment of the knee. Patients are assessed preoperatively for ligamentous stability of the knee, mechanical alignment, and associated chondral injuries to determine whether secondary procedures may be indicated. Technique Description: We present an all-arthroscopic technique for LMAT using small bone plugs in the anterior and posterior meniscus roots secured through 2 separate anatomic root drill tunnels tied over a bone bridge. The meniscus allograft is further secured using an outside-in suture repair technique. Special attention is given to meniscus allograft preparation, anatomic meniscus root identification, and drilling using a minimally disruptive transphyseal technique. Graft passage, suture management, and meniscus fixation and repair are also highlighted. Results: Anticipated outcomes from LMAT in skeletally mature patients are excellent, particularly if preexisting chondral degenerative changes are not present. Prior studies with greater than 7-year follow-up in adolescent patients undergoing meniscus allograft transplantation have shown reoperation rates of less than 6% with no growth disturbances noted, with most patients able to return to their prior level of sport. Computed tomography modeling data using this technique shows a proximal tibial physeal surface area disruption of less than 2.5%; therefore, the risk of growth disturbance is very low. Discussion/Conclusion: The surgical technique demonstrated here offers a safe and effective approach for the management of lateral meniscus deficiency after subtotal lateral meniscectomy for irreparable meniscus tears in skeletally immature patients. The chondroprotective effect of the lateral meniscus can be restored with an anatomically placed lateral meniscus allograft with minimal disruption to the proximal tibial physis.

One-Stage ACL Revision Using a Bone Allograft Plug for a Semianatomic Tibial Tunnel That Is Too Anterior

Revision of an anterior cruciate ligament (ACL) reconstruction can be performed as a one-stage or two-stage surgery. Several factors must be taken into consideration when making this choice, especially the size and position of the existing tunnels. When the tibial tunnel is semianatomic, it is difficult to make a new tunnel in the correct position without overlapping the existing tunnel. For this reason, we have developed a one-stage ACL revision surgery that uses a bone allograft plug. When it comes to choosing a reconstruction technique, we believe that combined intra-articular and extra-articular reconstruction with the iliotibial band is suitable when the hamstring tendons are not available, combined with clinical findings of translational and rotational instability. Because the existing tunnels require reorientation, a new femoral tunnel can be created by outside-in drilling to eliminate the risk of overlap, while an allograft bone plug can be used to fill the overly anterior tibial tunnel and allow us to drill the correct tibial tunnel right away. In our hands, this is a safe and effective technique, but longer follow-up is needed to validate its indications.

Allograft contamination during suture preparation for anterior cruciate ligament reconstruction: an ex vivo study.

Effects of suture preparation on graft contamination remain unknown in anterior cruciate ligament reconstruction (ACLR). This study aimed to evaluate the incidence of allograft contamination at different time points of graft preparation and investigate differences in contamination between different sites of the allografts. Fourteen hamstring tendon (HT), 9 quadriceps tendon (QT), and 9 bone-patellar tendon-bone (BTB) allografts were harvested, sterilised, and stored following routine procedures. Graft suture preparation was performed with baseball stitching for soft tissue and bone drilling for bone plug. The time was recorded simultaneously. The graft was kept moist in a standard operating room environment for 30min after the initiation of preparation. The specimens were obtained from the middle and both ends of each graft for culture at three different time points: pre-suturing, post-suturing, and 30min after the initiation of preparation. A total of 192 specimens were transferred to the microbiology laboratory for culture, identification, and semi-quantitative assessment. Culture results were classified as negative, poor, and abundant based on the extent of growth. Contamination level was recorded as low or high corresponding to culture results of poor or abundant. The duration of suture preparation was 348, 301, and 246s for HT, QT, and BTB (P = 0.090). The specimens had a positive culture rate of 41/192 (21.4%), of which 21 were from the ends and 20 from the middle. More positive samples with abundant bacterial growth were detected from the ends than from the middles post-suturing (7/8 vs. 1/7, P = 0.010) and at 30min (6/11 vs. 0/11, P = 0.012). The total graft contamination rate was significantly higher at 30min (19/32, 59.4%) than pre-suturing (4/32, 15.6%) and post-suturing (9/32, 28.1%) (P < 0.001). The contamination rate with abundant bacterial growth was higher post-suturing (7/32, 21.9%) than pre-suturing (0%). No statistically significant differences were found among the three types of allografts. The contamination rate increases significantly at 30min compared with pre-suturing and post-suturing. Suture preparation may have introduced the high-level contamination, to which the ends of the graft were more prone than the middle. Therefore, routine prophylactic decontamination after suture preparation should be considered, especially for the ends of the grafts.

Biomechanical Comparison of Meniscal Allograft Root Fixation Techniques: Anterograde Interference Bone Plug Fixation Yields Favorable Results Compared to Transosseous Suture Fixation Alone

PurposeTo compare the biomechanical properties of 2 different fixation techniques (interference bone plug fixation vs transosseous suture fixation) of the posterior horn of the medial meniscus using a porcine model.MethodsTwenty-six matched pairs of fresh-frozen juvenile domestic porcine knees were used in this study. Specimens were randomly distributed among 3 groups: (1) native meniscus groups, (2) interference fixation, and (3) transosseous suture fixation. In each group, the posterior segments of the tested medial menisci were gripped with the freeze clamps and fixed to the tensile testing machine. Samples were preconditioned, followed by cyclic tension-relaxation for 1000 cycles between 10 and 30 N at 0.5 Hz and finally pulled to failure at a rate of 0.55 mm/s. The cyclic elongation, stiffness to failure, mode, and ultimate load to failure were recorded.ResultsThere was no significant difference in ultimate load to failure between the interference fixation (169.71 ± 71.98 N) and transosseous suture fixation (222.73 ± 72.40 N) groups (P = .118), both were significantly less than that of the native meniscus (405.46 ± 95.62) (P < .001). Interference fixation displayed cyclic elongation (1.04 ± 0.71 mm) and stiffness (69.10 ± 25.8 N/mm) that were not significantly different from the native meniscus tissue (0.78 ± 0.53 mm and 83.1 ±26.28 N/mm) (P = .359 and P = .224), in comparison to transosseous suture fixation, which did show increased cyclic elongation (1.85 ± 1.44 mm) (P = .047) and decreased stiffness (34.72 ± 10.2 N/mm) (P < .001).ConclusionInterference fixation of the posterior horn of the medial meniscus has superior cyclic elongation and stiffness when compared to transosseous suture fixation. Interference fixation and the native meniscus model have a similar stiffness and cyclic elongation.Clinical RelevanceThe significance of our study is that using interference fixation for meniscal allograft transplantation has the potential to reduce short term surgical failures as well as long term complication rates.

Medial Meniscal Allograft Transplantation With Bone Plugs Using a 3-Tunnel Technique

Meniscal allograft transplantation is an area of active research, given that the importance of the meniscus in native knee joint longevity has been increasingly recognized. This article describes a modified meniscal allograft transplantation technique using 3 bone tunnels with allograft fixation through the use of bone plugs. The addition of a third tunnel increases the strength of fixation, avoiding meniscal extrusion and improving load distribution.