A lateral extra-articular tenodesis without additional hardware: Surgical technique and biomechanical comparison with an anatomic anterolateral ligament reconstruction in the augmentation of anterior cruciate ligament reconstruction.

BACKGROUND: The aims of this study were to describe a lateral extra-articular tenodesis (LET) using no additional hardware and compare the tibiofemoral kinematics of anterior cruciate ligament (ACL) reconstruction augmented with either the LET or a standard anatomic anterolateral ligament (ALL) reconstruction using intra-tunnel fixation. METHODS: Ten cadaveric knees were mounted on a robotic testing system and underwent a kinematic assessment of anterior tibial translation and internal tibial rotation under a simulated pivot-shift in the following states: ACL-intact, ACL-sectioned, ACL-sectioned/anterolateral complex (ALC)-sectioned, ACL-reconstructed/ALC-sectioned, ACL-reconstructed/ALL-reconstructed, and ACL-reconstructed/LET. For the LET, an iliotibial autograft was passed under the fibular collateral ligament and secured to the femur with the pull sutures of the ACL reconstruction femoral cortical suspensory fixation device, positioned at the distal ridge of Kaplan's fibers. RESULTS: Anterior tibial translation was restored to normal by ACL reconstruction without meaningful benefit of augmentation with LET or ALL. ACL reconstruction restored internal tibial rotation close to normal between 0° and 30°, but increased internal tibial rotation persisted between 45° and 90°. Augmentation of ACL reconstruction with the LET reduced internal rotation close to normal between 45° and 90°, whereas increased internal rotation persisted after ALL reconstruction. CONCLUSION: ACL reconstruction and LET are complementary in controlling tibiofemoral kinematics of knees with a combined ACL and ALC injury: ACL reconstruction restored native tibiofemoral kinematics except for internal rotation at flexion greater than 30°. The increased internal rotation at flexion greater than 30° was restored to normal with an LET, but not with an ALL reconstruction.

Cost-effectiveness of arthroscopic partial meniscectomy versus physical therapy for traumatic meniscal tears in patients aged under 45 years.

Aims: The aim of this study was to evaluate the cost-effectiveness of arthroscopic partial meniscectomy versus physical therapy plus optional delayed arthroscopic partial meniscectomy in young patients aged under 45 years with traumatic meniscal tears. Methods: We conducted a multicentre, open-labelled, randomized controlled trial in patients aged 18 to 45 years, with a recent onset, traumatic, MRI-verified, isolated meniscal tear without knee osteoarthritis. Patients were randomized to arthroscopic partial meniscectomy or standardized physical therapy with an optional delayed arthroscopic partial meniscectomy after three months of follow-up. We performed a cost-utility analysis on the randomization groups to compare both treatments over a 24-month follow-up period. Cost utility was calculated as incremental costs per quality-adjusted life year (QALY) gained of arthroscopic partial meniscectomy compared to physical therapy. Calculations were performed from a healthcare system perspective and a societal perspective. Results: A total of 100 patients were included: 49 were randomized to arthroscopic partial meniscectomy and 51 to physical therapy. In the physical therapy group, 21 patients (41%) received delayed arthroscopic partial meniscectomy during follow-up. Over 24 months, patients in the arthroscopic partial meniscectomy group had a mean 0.005 QALYs lower quality of life (95% confidence interval -0.13 to 0.14). The cost-utility ratio was €-160,000/QALY from the healthcare perspective and €-223,372/QALY from the societal perspective, indicating that arthroscopic partial meniscectomy incurs additional costs without any added health benefit. Conclusion: Arthroscopic partial meniscectomy is arthroscopic partial meniscectomy is unlikely to be cost-effective in treating young patients with isolated traumatic meniscal tears compared to physical therapy as a primary health intervention. Arthroscopic partial meniscectomy leads to a similar quality of life, but higher costs, compared to physical therapy plus optional delayed arthroscopic partial meniscectomy.

The role of patient characteristics and the effects of angiogenic therapies on the microvasculature of the meniscus: A systematic review.

BACKGROUND: Considerable interindividual variation in meniscal microvascularization has been reported. The purpose of this review was to identify which patient characteristics affect meniscal microvascularization and provide a structured overview of angiogenic therapies that influence meniscal neovascularization. METHODS: A systematic literature search was undertaken using PubMed, Embase, Web of Science, Cochrane library and Emcare from inception to November 2021. Studies reporting on (1) Patient characteristics that affect meniscal microvascularization, or (2) Therapies that induce neovascularization in meniscal tissue were included. Studies were graded in quality using the Anatomical Quality Assessment (AQUA) tool. The study was registered with PROSPERO(ID:CRD42021242479). RESULTS: Thirteen studies reported on patient characteristics and eleven on angiogenic therapies. The influence of Age, Degenerative knee, Gender, and Race was reported. Age is the most studied factor. The entire meniscus is vascularized around birth. With increasing age, vascularization decreases from the inner to the peripheral margin. Around 11 years, blood vessels are primarily located in the peripheral third of the menisci. There seems to be a further decrease in vascularization with increasing age in adults, yet conflicting literature exists. Degenerative changes of the knee also seem to influence meniscal vascularization, but evidence is limited. Angiogenic therapies to improve meniscal vascularization have only been studied in preclinical setting. The use of synovial flap transplantation, stem cell therapy, vascular endothelial growth factor, and angiogenin has shown promising results. CONCLUSION: To decrease failure rates of meniscal repair, a better understanding of patient-specific vascular anatomy is essential. Translational clinical research is needed to investigate the clinical value of angiogenic therapies.

Arthroscopic partial meniscectomy versus physical therapy for traumatic meniscal tears in a young study population: a randomised controlled trial.

OBJECTIVE: To compare outcomes from arthroscopic partial meniscectomy versus physical therapy in young patients with traumatic meniscal tears. METHODS: We conducted a multicentre, open-labelled, randomised controlled trial in patients aged 18-45 years, with a recent onset, traumatic, MRI-verified, isolated meniscal tear without knee osteoarthritis. Patients were randomised to arthroscopic partial meniscectomy or standardised physical therapy with an optional delayed arthroscopic partial meniscectomy after 3-month follow-up. The primary outcome was the International Knee Documentation Committee (IKDC) score (best 100, worst 0) at 24 months, which measures patients' perception of symptoms, knee function and ability to participate in sports activities. RESULTS: Between 2014 and 2018, 100 patients were included (mean age 35.1 (SD 8.1), 76% male, 34 competitive or elite athletes). Forty-nine were randomised to arthroscopic partial meniscectomy and 51 to physical therapy. In the physical therapy group, 21 patients (41%) received delayed arthroscopic partial meniscectomy during the follow-up period. In both groups, improvement in IKDC scores was clinically relevant during follow-up compared with baseline scores. At 24 months mean (95% CI) IKDC scores were 78 (71 to 84) out of 100 points in the arthroscopic partial meniscectomy group and 78 (71 to 84) in the physical therapy group with a between group difference of 0.1 (95% CI -7.6 to 7.7) points out of 100. CONCLUSIONS: In this trial involving young patients with isolated traumatic meniscal tears, early arthroscopic partial meniscectomy was not superior to a strategy of physical therapy with optional delayed arthroscopic partial meniscectomy at 24-month follow-up. TRIAL REGISTRATION: https://www.trialregister.nl/trials.

Intra-operative assessment of the vascularisation of a cross section of the meniscus using near-infrared fluorescence imaging.

PURPOSE: The purpose of this study was to assess whether the vascularisation of the meniscus could be visualised intra-operatively using near-infrared fluorescence (NIRF) imaging with indocyanine green (ICG) in patients undergoing total knee arthroplasty (TKA). METHODS: The anterior horn (i.e., Cooper classification: zones C and D) of the meniscus that was least affected (i.e., least degenerative) was removed during TKA surgery in ten patients to obtain a cross section of the inside of the meniscus. Thereafter, 10 mg of ICG was injected intravenously, and vascularisation of the cross section of the meniscus was assessed using the Quest spectrum NIRF camera system. We calculated the percentage of patients in whom vascularisation was observed intra-operatively using NIRF imaging compared to immunohistochemistry. RESULTS: Meniscal vascularisation using NIRF imaging was observed in six out of eight (75%) patients in whom vascularisation was demonstrated with immunohistochemistry. The median extent of vascularisation was 13% (interquartile range (IQR) 3-28%) using NIRF imaging and 15% (IQR 11-23%) using immunohistochemistry. CONCLUSION: This study shows the potential of NIRF imaging to visualise vascularisation of the meniscus, as vascularisation was observed in six out of eight patients with histologically proven meniscal vascularisation. LEVEL OF EVIDENCE: IV.

[A woman with acute-onset shoulder pain]. / Een vrouw met acuut ontstane schouderklachten.

In this case report we present a 55-year-old female patient with acute-onset shoulder pain. X-rays of the affected shoulder showed clear levels of resorbed calcium in an enlarged subacromial bursa which is typical for the resorptive phase of calcific tendinitis of the rotator cuff.

Dutch Guideline on Knee Arthroscopy Part 2: non-meniscus intra-articular knee injury: a multidisciplinary review by the Dutch Orthopaedic Association.

Background and purpose - A guideline committee of medical specialists and a physiotherapist was formed on the initiative of the Dutch Orthopedic Association (NOV) to update the Guideline Arthroscopy of the Knee: Indications and Treatment 2010. This next Guideline was developed between June 2017 and December 2019. In part 1 we focused on the meniscus; this part 2 addresses all other aspects of knee arthroscopy.Methods - The guideline was developed in accordance with the criteria of the AGREE instrument (AGREE II: Appraisal of Guidelines for Research and Evaluation II) with support of a professional methodologist from the Dutch Knowledge Institute of Medical Specialists. The scientific literature was searched and systematically analyzed. Conclusions and recommendations were formulated according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) method. Recommendations were developed considering the balance of benefits and harms, the type and quality of evidence, the values and preferences of the people involved, and the costs.

Dutch Guideline on Knee Arthroscopy Part 1, the meniscus: a multidisciplinary review by the Dutch Orthopaedic Association.

Background and purpose - A guideline committee of medical specialists and a physiotherapist was formed on the initiative of the Dutch Orthopedic Association (NOV) to update the guideline Arthroscopy of the Knee: Indications and Treatment 2010. This next guideline was developed between June 2017 and December 2019. In this Part 1 we focus on the meniscus, in Part 2 on all other aspects of knee arthroscopy.Methods - The guideline was developed in accordance with the criteria of the AGREE instrument (AGREE II: Appraisal of Guidelines for Research and Evaluation II) with support of a professional methodologist from the Dutch Knowledge Institute of Medical Specialists. The scientific literature was searched and systematically analyzed. Conclusions and recommendations were formulated according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) method. Recommendations were developed considering the balance of benefits and harms, the type and quality of evidence, the values and preferences of the people involved, and the costs.

Functional Outcomes of Arthroscopic Partial Meniscectomy Versus Physical Therapy for Degenerative Meniscal Tears Using a Patient-Specific Score: A Randomized Controlled Trial.

BACKGROUND: It is unknown whether the treatment effects of partial meniscectomy and physical therapy differ when focusing on activities most valued by patients with degenerative meniscal tears. PURPOSE: To compare partial meniscectomy with physical therapy in patients with a degenerative meniscal tear, focusing on patients' most important functional limitations as the outcome. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: This study is part of the Cost-effectiveness of Early Surgery versus Conservative Treatment with Optional Delayed Meniscectomy for Patients over 45 years with non-obstructive meniscal tears (ESCAPE) trial, a multicenter noninferiority randomized controlled trial conducted in 9 orthopaedic hospital departments in the Netherlands. The ESCAPE trial included 321 patients aged between 45 and 70 years with a symptomatic, magnetic resonance imaging-confirmed meniscal tear. Exclusion criteria were severe osteoarthritis, body mass index >35 kg/m2, locking of the knee, and prior knee surgery or knee instability due to an anterior or posterior cruciate ligament rupture. This study compared partial meniscectomy with physical therapy consisting of a supervised incremental exercise protocol of 16 sessions over 8 weeks. The main outcome measure was the Dutch-language equivalent of the Patient-Specific Functional Scale (PSFS), a secondary outcome measure of the ESCAPE trial. We used crude and adjusted linear mixed-model analyses to reveal the between-group differences over 24 months. We calculated the minimal important change for the PSFS using an anchor-based method. RESULTS: After 24 months, 286 patients completed the follow-up. The partial meniscectomy group (n = 139) improved on the PSFS by a mean of 4.8 ± 2.6 points (from 6.8 ± 1.9 to 2.0 ± 2.2), and the physical therapy group (n = 147) improved by a mean of 4.0 ± 3.1 points (from 6.7 ± 2.0 to 2.7 ± 2.5). The crude overall between-group difference showed a -0.6-point difference (95% CI, -1.0 to -0.2; P = .004) in favor of the partial meniscectomy group. This improvement was statistically significant but not clinically meaningful, as the calculated minimal important change was 2.5 points on an 11-point scale. CONCLUSION: Both interventions were associated with a clinically meaningful improvement regarding patients' most important functional limitations. Although partial meniscectomy was associated with a statistically larger improvement at some follow-up time points, the difference compared with physical therapy was small and clinically not meaningful at any follow-up time point. REGISTRATION: NCT01850719 (ClinicalTrials.gov identifier) and NTR3908 (the Netherlands Trial Register).

Meniscal allograft transplantation in The Netherlands: long-term survival, patient-reported outcomes, and their association with preoperative complaints and interventions.

PURPOSE: Evaluation of survival of meniscal allograft transplantation (MAT) and postoperative patient-reported outcome (PRO), and their association with prior interventions of the knee. METHODS: A prospective consecutive study of 109 consecutive patients who had an arthroscopic meniscal allograft transplantation (MAT) between 1999 and 2017 by a single surgeon. Patients were assessed with KOOS scores, preoperative and after a minimal follow-up of 2 years. Furthermore, two anchor questions (whether expectations were met and overall satisfaction, on a five-point Likert scale) were asked. Additionally, prior interventions to MAT were evaluated. RESULTS: Prior to MAT, patients had undergone an average of 2.8 (range 1-14) of surgical procedures of the knee. Overall, mean allograft survival was 16.1 years (95% CI 14.8-17.5 years). Higher age at surgery was associated with lower MAT survival: hazard ratio for MAT failure was 1.19 per year increase (95% CI 1.04 to 1.36, p = 0.009). At 4.5 years (IQR, 2-9) of follow-up, all KOOS score were still improved compared to baseline. Age below 35 years, simultaneous anterior cruciate ligament reconstruction and number of knee surgeries before MAT were associated with lower KOOS scores. Overall patient expectations and overall satisfaction after MAT were not associated with preoperative patient characteristics nor with the number or kind of preoperative interventions. CONCLUSION: Meniscal allograft transplantation has a good overall survival with a clinically relevant improvement. Both meniscal allograft survival and PRO were associated with age. PRO was lower in patients younger than 35 years at time of MAT and meniscal allograft survival was worse in patients older than 50 years. PRO was associated with preoperative patient characteristics and number of surgical procedures prior to MAT. All patients reported improved postoperative satisfaction and met expectations after MAT, both independent of the preoperative history of knee interventions. LEVEL OF EVIDENCE: Level III. Trial registration Medical ethical review board (METC) number: 17-104 (7 August 2017). Dutch Trial Register (NTR) number: NTR6630 (4 July 2017).

[Anterior cruciate ligament rupture in children: A growing problem]. / Voorste-kruisbandruptuur bij kinderen.

The number of knee injuries in young children has risen sharply in recent years, due to more intensive participation in sporting activities by children at an increasingly lower age. This has led to more anterior cruciate ligament (ACL) ruptures. An ACL rupture has major consequences for the young athlete, but diagnosing this injury in a child can be difficult due to pain and anxiety. The criteria for appropriate treatment of an ACL rupture are not always clear for the child, the doctor, the parents and the sporting coach. Here we describe the diagnosis and possible treatment options for an ACL rupture in children based on three cases. We conclude that the incidence of ACL ruptures in children is a growing problem. There is a challenge for sports associations, sports clubs, trainers and parents to build in prevention programmes during weekly training sessions. The considerations to be taken into account concerning diagnosis and different treatment options show, once again, that children cannot simply be considered as small adults.

The Occurrence of Meniscal and Chondral Injury in Two-Stage Revision Anterior Cruciate Ligament Reconstruction: A Consecutive Case Series.

Two-stage revision anterior cruciate ligament (ACL) reconstruction is an effective way to revise suboptimal tunnel-placement allowing for proper graft fixation. However, prolonged increased laxity of the knee may increase the risk of meniscal or chondral injury. It was hypothesized that no additional meniscal or chondral lesions occur in between the two stages of the two-stage revision ACL reconstruction. In this retrospective study, 42 patients undergoing a two-stage revision ACL reconstruction were included. Surgical notes for both stages were screened for meniscal and chondral status, interventions to any concurrent injury, surgery dates, along with basic patient characteristics. In 4 of the 42 patients, a new meniscal tear occurred in between the two stages, of which three required partial meniscectomy during the second stage of the ACL revision. One patient experienced a new small degenerative tear that did not require intervention. Two out of the four menisci that were repaired during the first stage had failed and required partial meniscectomy. No significant difference was found in the time between the two stages with respect to the occurrence of meniscal tears. No significant differences in chondral status were found. In conclusion, approximately 10% of patients developed a new meniscal tear and no difference in macroscopic chondral injury was observed between the first and second stages.

The Medial Patellofemoral Ligament Is a Dynamic and Anisometric Structure: An In Vivo Study on Length Changes and Isometry.

BACKGROUND: Medial patellofemoral ligament (MPFL) reconstruction is associated with a high rate of complications, including recurrent instability and persistent knee pain. Technical errors are among the primary causes of these complications. Understanding the effect of adjusting patellofemoral attachments on length change patterns may help surgeons to optimize graft placement during MPFL reconstruction and to reduce graft failure rates. PURPOSE: To determine the in vivo length changes of the MPFL during dynamic, weightbearing motion and to map the isometry of the 3-dimensional wrapping paths from various attachments on the medial femoral epicondyle to the patella. STUDY DESIGN: Descriptive laboratory study. METHODS: Fifteen healthy participants were studied with a combined computed tomography and biplane fluoroscopic imaging technique during a lunge motion (full extension to ~110° of flexion). On the medial femoral epicondyle, 185 attachments were projected, including the anatomic MPFL footprint, which was divided into 5 attachments (central, proximal, distal, posterior, and anterior). The patellar MPFL area was divided into 3 possible attachments (proximal, central, and distal). The length changes of the shortest 3-dimensional wrapping paths of the various patellofemoral combinations were subsequently measured and mapped. RESULTS: For the 3 patellar attachments, the most isometric attachment, with an approximate 4% length change, was located posterior and proximal to the anatomic femoral MPFL attachment, close to the adductor tubercle. Attachments proximal and anterior to the isometric area resulted in increasing lengths with increasing knee flexion, whereas distal and posterior attachments caused decreasing lengths with increasing knee flexion. The anatomic MPFL was tightest in extension, decreased in length until approximately 30° of flexion, and then stayed near isometric for the remainder of the motion. Changing both the femoral and patellar attachments significantly affected the length changes of the anatomic MPFL ( P < .001 for both). CONCLUSION: The most isometric location for MPFL reconstruction was posterior and proximal to the anatomic femoral MPFL attachment. The anatomic MPFL is a dynamic, anisometric structure that was tight in extension and early flexion and near isometric beyond 30° of flexion. CLINICAL RELEVANCE: Proximal and anterior MPFL tunnel positioning should be avoided, and the importance of anatomic MPFL reconstruction is underscored with the results found in this study.

Anatomic is better than isometric posterior cruciate ligament tunnel placement based upon in vivo simulation.

PURPOSE: To elucidate the effects of various tibial and femoral attachment locations on the theoretical length changes and isometry of PCL grafts in healthy knees during in vivo weightbearing motion. METHODS: The intact knees of 14 patients were imaged using a combined magnetic resonance and dual fluoroscopic imaging technique while the patient performed a quasi-static lunge (0°-120° of flexion). The theoretical end-to-end distances of the 3-dimensional wrapping paths between 165 femoral attachments, including the anatomic anterolateral bundle (ALB), central attachment and posteromedial bundle (PMB) of the PCL, connected to an anterolateral, central, and posteromedial tibial attachment were simulated and measured. A descriptive heatmap was created to demonstrate the length changes on the medial condyle and formal comparisons were made between the length changes of the anatomic PCL and most isometric grafts. RESULTS: The most isometric graft, with approximately 3% length change between 0° and 120° of flexion, was located proximal to the anatomic femoral PCL attachments. Grafts with femoral attachments proximal to the isometric zone decreased in length with increasing flexion angles, whereas grafts with more distal attachments increased in length with increasing flexion angles. The ALB and central single-bundle graft demonstrated a significant elongation from 0° to 120° of flexion (p < 0.001). The PMB decreased in length between 0° and 60° of flexion after which the bundle increased in length to its maximum length at 120° (p < 0.001). No significant differences in length changes were found between either the ALB or PMB and the central graft, and between the ALB and PMB at flexion angles ≥ 60° (n.s.). CONCLUSIONS: The most isometric attachment was proximal to the anatomic PCL footprint and resulted in non-physiological length changes. Moving the femoral attachment locations of the PCL significantly affected length change patterns, whereas moving the tibia locations did not. The importance of anatomically positioned (i.e., distal to the isometric area) femoral PCL reconstruction locations to replicate physiological length changes is highlighted. These data can be used to optimize tunnel positioning in either single- or double-bundle and primary or revision PCL reconstruction cases. LEVEL OF EVIDENCE: IV.

The effect of ACL deficiency on the end-to-end distances of the tibiofemoral ACL attachment during in vivo dynamic activity.

PURPOSE: To evaluate the effect of ACL deficiency on the in vivo changes in end-to-end distances and to determine appropriate graft fixation angles for commonly used tunnel positions in contemporary ACL reconstruction techniques. METHODS: Twenty-one patients with unilateral ACL-deficient and intact contralateral knees were included. Each knee was studied using a combined magnetic resonance and dual fluoroscopic imaging technique while the patients performed a dynamic step-up motion (~50° of flexion to extension). The end-to-end distances of the centers of the anatomic anteromedial (AM), posterolateral (PL) and single-bundle ACL reconstruction (SB-anatomic) tunnel positions were simulated and analyzed. Comparisons were made between the elongation patterns between the intact and ACL-deficient knees. Additionally, a maximum graft length change of 6% was used to calculate the deepest flexion fixation angle. RESULTS: ACL-deficient knees had significantly longer graft lengths when compared with the intact knees for all studied tunnel positions (p < 0.01). The end-to-end distances for the AM, PL and SB-anatomic grafts were significantly longer between 0-30° of flexion when compared with the intact knee by p < 0.05 for all. Six percent length change occurred with fixation of the AM bundle at 30° of flexion, PL bundle at 10° and the SB-anatomic graft at 20°. CONCLUSIONS: ACL-deficient knees had significantly longer in vivo end-to-end distances between 0°-30° of flexion for grafts at the AM, PL and SB-anatomic tunnel positions when compared with the intact knees. Graft fixation angles of <30° for the AM, <10° for the PL, and <20° for the SB-anatomic grafts may prevent permanent graft stretch.

Two-year follow-up of bone mineral density changes in the knee after meniscal allograft transplantation: Results of an explorative study.

BACKGROUND: The potential chondroprotective effect of meniscal allograft transplantation (MAT) is unclear. Subchondral bone mineral density (BMD) and subchondral bone remodeling play important roles in osteoarthritis development. Evaluation of subchondral BMD after MAT might give more insight into the potential chondroprotective effect. The purpose of this study was to determine early BMD changes in the knee after MAT. METHODS: Twenty-six consecutive patients underwent MAT during 2010-2013. The BMD was measured using dual-energy x-ray absorptiometry (DXA) scan preoperatively, and six months, one and two years postoperatively. Bone mineral density was measured in six regions of interest (ROIs) in the tibia and femur (medial, central, lateral) in both treated and healthy contralateral knees. RESULTS: The BMD levels of MAT knees did not significantly change during two years of follow-up in almost all ROIs. Bone mineral density was significant higher in nearly all ROIs in MAT knees at almost all follow-ups compared to healthy contralateral knees. In the healthy contralateral knees, BMD slightly, but not statistically, decreased in the first postoperative year, where it normalized to baseline values at two-year follow-up. The BMD levels in all ROIs did not significantly differ between the patients with or without chondropathy at baseline and two-year follow-up. CONCLUSION: Based on the findings, MAT did not show a significant influence on BMD in the first two postoperative years. Longer follow-up is necessary to prove the potential chondroprotective effect of MAT using BMD measurements.

Predictive Factors of Hamstring Tendon Regeneration and Functional Recovery After Harvesting: A Prospective Follow-up Study.

BACKGROUND: Semitendinosus and gracilis tendons may regenerate after harvesting for ligament reconstruction procedures. However, predictive factors of tendon regeneration and the extent of functional recovery remain unclear. PURPOSE: To identify predictive factors for hamstring tendon regeneration and to examine the morbidity of nonregenerated hamstring tendons. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Of the 154 patients who were included in a prospective follow-up study, 79 underwent reconstruction of the anterior cruciate ligament entailing the hamstring tendons and met the following inclusion criteria: (1) anterior cruciate ligament rupture diagnosed by physical examination and magnetic resonance imaging (MRI), (2) MRI within 6 months after trauma, (3) age between 18 and 45 years, and (4) 2-year follow-up MRI data available. Hamstring tendon regeneration was assessed as complete if a tendon-like structure could be visualized at the level of the joint line or more cranially. Patient characteristics-such as age, sex, body mass index, alcohol/nicotine use, activity level (Tegner scores), and functional instability (1-legged hop test)-were evaluated preoperatively and at 2 years to determine predictive factors for tendon regeneration or examine functional recovery of hamstring tendon regeneration. RESULTS: At 2 years' follow-up, 67.1% of the patients showed regeneration of semitendinosus tendons, 81.0% of gracilis tendons, and 59.5% of both tendons. The likelihood of semitendinosus tendon regeneration significantly decreased with aging (odds ratio [OR], 0.92 change per year of age; 95% CI, 0.84-0.99; P = .03) and smoking (OR, 0.20; 95% CI, 0.05-0.77; P = .02). No predictive factor was found for gracilis tendon regeneration. Regeneration of the semitendinosus and gracilis tendons was negatively related with smoking (OR, 0.22; 95% CI, 0.06-0.79; P = .02). Patients without regeneration showed similar postoperative visual analog scale scores during physical activity, similar Tegner scores, and a significant decrease of the upper leg circumference, as compared with their preoperative results. Regardless of the regeneration status, 1-legged hop test results significantly increased at 2-year follow-up. CONCLUSION: Hamstring tendon regeneration occurs less frequently in older patients and in smokers. However, absence of regenerated tendons does not seem to cause a loss of function.

An In Vivo Prediction of Anisometry and Strain in Anterior Cruciate Ligament Reconstruction - A Combined Magnetic Resonance and Dual Fluoroscopic Imaging Analysis.

PURPOSE: To evaluate the in vivo anisometry and strain of theoretical anterior cruciate ligament (ACL) grafts in the healthy knee using various socket locations on both the femur and tibia. METHODS: Eighteen healthy knees were imaged using magnetic resonance imaging and dual fluoroscopic imaging techniques during a step-up and sit-to-stand motion. The anisometry of the medial aspect of the lateral femoral condyle was mapped using 144 theoretical socket positions connected to an anteromedial, central, and posterolateral attachment site on the tibia. The 3-dimensional wrapping paths of each theoretical graft were measured. Comparisons were made between the anatomic, over the top (OTT), and most-isometric (isometric) femoral socket locations, as well as between tibial insertions. RESULTS: The area of least anisometry was found in the proximal-distal direction just posterior to the intercondylar notch. The most isometric attachment site was found midway on the Blumensaat line with approximately 2% and 6% strain during the step-up and sit-to-stand motion, respectively. Posterior femoral attachments resulted in decreased graft lengths with increasing flexion angles, whereas anterodistal attachments yielded increased lengths with increasing flexion angles. The anisometry of the anatomic, OTT and isometric grafts varied between tibial insertions (P < .001). The anatomic graft was significantly more anisometric than the OTT and isometric graft at deeper flexion angles (P < .001). CONCLUSIONS: An area of least anisometry was found in the proximal-distal direction just posterior to the intercondylar notch. ACL reconstruction at the isometric and OTT location resulted in nonanatomic graft behavior, which could overconstrain the knee at deeper flexion angles. Tibial location significantly affected graft strains for the anatomic, OTT, and isometric socket location. CLINICAL RELEVANCE: This study improves the knowledge on ACL anisometry and strain and helps surgeons to better understand the consequences of socket positioning during intra-articular ACL reconstruction.

An in Vivo Simulation of Isometry of the Anterolateral Aspect of the Healthy Knee.

BACKGROUND: To assess the isometry of theoretical lateral extra-articular reconstruction (LER), we evaluated theoretical grafts attached to various points on the lateral femoral condylar area and to either Gerdy's tubercle or the anatomic attachment site of the anterolateral ligament to the tibia. METHODS: In 18 subjects, healthy knees with no history of either injury or surgery involving the lower extremity were studied. The subjects performed a sit-to-stand motion (from approximately 90° of flexion to full extension), and each knee was studied using magnetic resonance and dual fluoroscopic imaging techniques. The 3-dimensional wrapping paths of each theoretical LER graft were measured. Grafts showing the least change in length during the sit-to-stand motion were considered to be the most isometric. RESULTS: The most isometric attachment site on the lateral femoral epicondyle to either of the studied tibial attachment sites was posterior-distal to the femoral attachment site of the fibular collateral ligament. The LER graft had a mean change in length of approximately 3%. Moving the femoral attachment site anteriorly resulted in increased length of the graft with increasing flexion; more posterior attachment sites resulted in decreased length with increasing flexion. Moving the attachment site in the proximal-distal direction had a less profound effect. Moving the tibial attachment site from Gerdy's tubercle to the tibial attachment site of the anterolateral ligament affected the overall isometric distribution on the lateral femoral epicondyle. CONCLUSIONS: The most isometric attachment site on the femur for an LER would be posterior-distal to the femoral attachment site of the fibular collateral ligament. Different length changes for LER grafts were identified with respect to different femoral attachment sites. Desirable graft fixation locations for treating anterolateral rotatory instability were found posterior-proximal to the femoral fibular collateral ligament attachment. CLINICAL RELEVANCE: The present data could be used both in biomechanical studies and in clinical studies as guidelines for planning LER surgical procedures.