Myung Sun Kim

In Vivo Stability and Clinical Comparison of Anterior Cruciate Ligament Reconstruction Using Low or High Femoral Tunnel Positions

Background: Several biomechanical studies have supported placing the femoral tunnel at a low position (10 or 2 o’clock) to achieve anterior and rotational knee stabilities after anterior cruciate ligament (ACL) reconstruction. However, no firm consensus has been reached regarding the merits and demerits of ACL reconstruction using a low femoral tunnel versus a high femoral tunnel (11 or 1 o’clock). Hypothesis: A low femoral tunnel position during ACL reconstruction provides better intraoperative stability (especially, rotational stability) and clinical outcomes than does a high femoral tunnel position. Study Design: Cohort study; Level of evidence 2. Methods: Sixty-two patients who underwent ACL reconstruction were equally allocated to low and high femoral tunnel groups; 58 were followed up for a minimum of 2 years (29 in the each group). After reconstruction and using a navigation system, the authors compared intraoperative anterior, internal rotational, and external rotational stabilities at 0°, 30°, 60°, and 90° of knee flexion and compared clinical outcomes, including Lysholm knee scores, Tegner activity scores, Lachman and pivot-shift test findings, and radiographic stabilities at final follow-up visits. Results: The low group showed significantly better intraoperative internal rotational stability at 0° and 30° of flexion but not at other angles (60° and 90°). Intraoperatively, no significant intergroup differences were found for anterior and external rotational stabilities at any flexion angle. Furthermore, clinical outcomes, including Lysholm knee and Tegner activity scores, showed no significant differences between the 2 groups at final follow-up visits (P > .05), and Lachman and pivot-shift test stability results and radiological stability data obtained at final follow-up were not significantly different between the 2 groups (P > .05). Conclusion: The low femoral tunnel group showed better internal rotational stability at time zero during ACL reconstruction but similar anterior and external rotational stabilities. No significant differences were observed between the 2 groups in terms of clinical outcomes and stabilities after a minimum follow-up of 2 years.

Kinematic study following double-bundle, anterior cruciate ligament reconstruction.

The purpose of this study was to evaluate tibiofemoral kinematics after double-bundle anterior cruciate ligament (ACL) reconstructions and compare them with those of successful single-bundle reconstructions and contralateral normal knees using open MR images. We obtained MR images based on the flexion angle without weight-bearing, from 20 patients with successful unilateral single-bundle (10 patients) and double-bundle (10 patients) ACL reconstructions with tibialis anterior allografts and a minimum 1-year follow-up. The MR images of the contralateral uninjured knees were used as normal controls. Sagittal images of the mid-medial and mid-lateral sections of the tibiofemoral compartments were used to measure the translation of the femoral condyles relative to the tibia. The mean translations of the medial femoral condyles on the tibial plateaus during knee joint motion showed no significant differences among normal, single-bundle, and double-bundle ACL reconstructed knees (all p>0.05). The mean translations of the lateral femoral condyles showed a significant difference between normal and single-bundle reconstructed knees, or between single-bundle and double-bundle reconstructed knees (p<0.05). However, there was no significant difference between normal and double-bundle reconstructed knees (p=0.220). These findings suggest that double-bundle ACL reconstruction restores normal kinematic tibiofemoral motion better than single-bundle reconstruction.RésuméLe but de cette étude était d’évaluer, par les images de résonnance magnétique, la cinématique tibio-fémorale après reconstruction du ligament croisé antérieur par double tunnel et de la comparer avec celle obtenue après réussite des reconstructions à un seul tunnel et celle du genou normal controlatéral. Nous avons étudié des images basées sur l’angle de flexion en décharge chez 20 patients après reconstruction par allogreffe tibiale antérieure suivis au moins un an : 10 avec succés de la reconstruction par un seul tunnel et 10 avec reconstruction par un double tunnel. Les images du genou controlatéral non traumatisé servaient de contrôle. Des images sagittales de la partie moyenne des compartiments fémoro-tibiaux permettaient la mesure de la translation des condyles fémoraux par rapport au tibia. La translation du condyle interne pendant la flexion du genou n’était pas différente entre le genou normal et la reconstruction par simple ou double tunnel (p>0,05). La translation du condyle externe était significativement différente entre le genou normal et la reconstruction par simple tunnel et entre les reconstructions par simple et double tunnel (p<0,05). Cependant il n’y avait pas de différence entre le genou normal et la reconstruction par double tunnel (p=0,220). Ces résultats suggèrent que la reconstruction du croisé antérieur par double tunnel restore mieux la cinématique du genou que la reconstruction par simple tunnel.

Total Ankle Arthroplasty following Revascularization of Avascular Necrosis of the Talar Body: Two Case Reports and Literature Review

Total ankle arthroplasty (TAA) has emerged as another solution to ankle arthritis, as it provides reliable pain relief, preserves motion, and facilitates recovery as compared with fusion. However, the use of cementless TAA to treat ankle osteoarthritis with avascular necrosis (AVN) of the talar body is contraindicated because the potential for good ingrowth and component fixation is low.2,3,9,10 The authors describe two cases of end-stage ankle arthritis combined with AVN of the talar body, in which cementless TAA was performed to preserve ankle mobility because magnetic resonance (MR) images and radionuclide bone scanning showed revascularization of the talus.

Human fascia lata ECM scaffold augmented with immobilized hyaluronan: inflammatory response and remodeling in the canine body wall and shoulder implantation sites

We postulate that immobilization of tyramine-substituted hyaluronan (THA) into an extracellular matrix (ECM) scaffold may be a strategy to promote an anti-inflammatory response to the ECM. Further, we posit that the implantation site could influence the inflammatory response and remodeling of an ECM scaffold. Eight beagles underwent implantation of fascia ECM grafts, treated with either immobilized low molecular weight (57 kDa) THA or water only, in both the shoulder injury and body wall sites. Dogs were euthanized at 12 weeks and fascia grafts harvested en bloc for histology. Grafts implanted at the body wall had significantly higher inflammatory cell infiltrate and vascularity, and significantly lower retardance (collagen density), than grafts at the shoulder, suggestive of a more intense, persistent, and perhaps degradative inflammatory and remodeling response at the body wall than shoulder injury site in the canine model. However, the presence of immobilized low MW THA had no effect on the inflammation response or remodeling of fascia ECM compared to water-treated controls. Importantly, these results suggest that the inflammatory response and remodeling of biomaterial implants depends on the location of implantation and therefore our animal models need to be carefully chosen. Further, the potential anti-inflammatory advantages of hyaluronan (HA) in wound healing do not appear to be realized when presenting it to the host as non-degradable hydrogel even if its capacity for binding HA binding protein is maintained. Further study treating ECM with uncross-linked (free) HA or immobilized low MW THA as a means to deliver free HA or other biomolecules to a surgical repair site is warranted.

Bone Graft Substitute Provides Metaphyseal Fixation for a Stemless Humeral Implant

Stemless humeral fixation has become an alternative to traditional total shoulder arthroplasty, but metaphyseal fixation may be compromised by the quality of the trabecular bone that diminishes with age and disease, and augmentation of the fixation may be desirable. The authors hypothesized that a bone graft substitute (BGS) could achieve initial fixation comparable to polymethylmethacrylate (PMMA) bone cement. Fifteen fresh-frozen human male humerii were randomly implanted using a stemless humeral prosthesis, and metaphyseal fixation was augmented with either high-viscosity PMMA bone cement (PMMA group) or a magnesium-based injectable BGS (OsteoCrete; Bone Solutions Inc, Dallas, Texas) (OC group). Both groups were compared with a control group with no augmentation. Initial stiffness, failure load, failure displacement, failure cycle, and total work were compared among groups. The PMMA and OC groups showed markedly higher failure loads, failure displacements, and failure cycles than the control group (P<.01). There were no statistically significant differences in initial stiffness, failure load, failure displacement, failure cycle, or total work between the PMMA and OC groups. The biomechanical properties of magnesium-based BGS fixation compared favorably with PMMA bone cement in the fixation of stemless humeral prostheses and may provide sufficient initial fixation for this clinical application. Future work will investigate the long-term remodeling characteristics and bone quality at the prosthetic-bone interface in an in vivo model to evaluate the clinical efficacy of this approach.

Cross-Cultural Adaptation of the Korean Version of the Boston Carpal Tunnel Questionnaire: Its Clinical Evaluation in Patients with Carpal Tunnel Syndrome Following Local Corticosteroid Injection

The aim of this study was to assess and validate the Korean version of the Boston Carpal Tunnel Questionnaire (K-BCTQ) in patients with carpal tunnel syndrome (CTS). After translation and cultural adaptation of the BCTQ to a Korean version, the K-BCTQ was administered to 54 patients with CTS; it was administered again after 2 weeks to assess reliability. Additionally, we administered K-DASH and EQ-5D to assess construct-validity. In a prospective study of responsiveness to clinical change, 29 of 54 patients were treated by ultrasonography-guided local corticosteroid injection therapy. The internal consistency of the K-BCTQ was high (Cronbachs alpha: 0.915) and the intra-class correlation coefficients were 0.931 for the symptom severity scale (P<0.001) and 0.844 for the functional severity scale (P<0.001). The construct-validity between the symptom severity scale and the K-DASH, and between the functional severity scale and the K-DASH were significantly correlated (both P<0.001). Clinical improvement was noted in 29 patients with injection therapy. The effect size of symptom severity was 0.67, and that of functional severity was 0.58. In conclusion, the K-BCTQ shows good reliability, construct-validity, and acceptable responsiveness after local corticosteroid injection therapy (Clinical trial number, KCT0000050).

An Evaluation of Forearm Deformities in Hereditary Multiple Exostoses: Factors Associated With Radial Head Dislocation and Comprehensive Classification

PURPOSEnThis study attempted to evaluate a series of patients with hereditary multiple exostoses (HME) who could not be categorized according to the widely accepted Masada classification and to identify radiographic variables such as radial bowing, ulnar shortening, ulnar variance, radial articular angle, and carpal slip predictive of deformity.nnnMETHODSnWe retrospectively reviewed data on 102 upper limbs of 53 pediatric patients with HME. Demographics, site of forearm involvement, and radiographic parameters were documented. Patients with exostoses of the forearms were categorized into 6 groups based on location of the exostoses and presence or absence of a dislocated radial head. Proportional ulnar shortening was calculated as the ratio of ulnar length to radial length.nnnRESULTSnAccording to the Masada classification, 4 limbs were normal, 10 were type I, 2 were type II, and 24 were type III. Sixty-six limbs were unclassifiable. We classified those 66 limbs using a modification of the Masada classification. Of the 106 limbs, 11 (10.3%) had a dislocated radial head. Based on the radiographic analysis, patients with proportional ulnar shortening of less than 0.9 had a higher risk of radial head dislocation than did those with proportional ulnar shortening of 0.9 or greater. Patients with radial bowing greater than 8.1% showed a higher frequency of radial head dislocation than did those with radial bowing of 8.1% or less. Exostoses of both the distal radius and ulna tended to increase the rate of radial head dislocation. A greater amount of negative ulnar variance caused more radial bowing and a greater radioarticular angle.nnnCONCLUSIONSnWe propose a new comprehensive forearm classification for patients with HME. Proportional ulnar shortening less than 0.9 and radial bowing 8.1% or greater can be used to predict the risk of radial head dislocation.nnnTYPE OF STUDY/LEVEL OF EVIDENCEnPrognostic IV.

SURGICAL TREATMENT OF PSEUDOSYNDACTYLY OF CHILDREN WITH EPIDERMOLYSIS BULLOSA: A CASE REPORT

Recessive dystrophic epidermolysis bullosa (RDEB) is an uncommon and severe disorder characterised by trauma-induced blisters, intractable skin ulcers, scarring, milia, and nail dystrophy. We report the good result of both surgical release of fingers allowing spontaneous epithelisation without skin grafting and post-operative meticulous skin care without splinting, followed-up for one year.

Development of an Arthroscopic Joint Capsule Injury Model in the Canine Shoulder.

Background The natural history of rotator cuff tears can be unfavorable as patients develop fatty infiltration and muscle atrophy that is often associated with a loss of muscle strength and shoulder function. To facilitate study of possible biologic mechanisms involved in early degenerative changes to rotator cuff muscle and tendon tissues, the objective of this study was to develop a joint capsule injury model in the canine shoulder using arthroscopy. Methods Arthroscopic surgical methods for performing a posterior joint capsulectomy in the canine shoulder were first defined in cadavers. Subsequently, one canine subject underwent bilateral shoulder joint capsulectomy using arthroscopy, arthroscopic surveillance at 2, 4 and 8 weeks, and gross and histologic examination of the joint at 10 weeks. Results The canine subject was weight-bearing within eight hours after index and follow-up surgeries and had no significant soft tissue swelling of the shoulder girdle or gross lameness. Chronic synovitis and macroscopic and microscopic evidence of pathologic changes to the rotator cuff bony insertions, tendons, myotendinous junctions and muscles were observed. Conclusions This study demonstrates feasibility and proof-of-concept for a joint capsule injury model in the canine shoulder. Future work is needed to define the observed pathologic changes and their role in the progression of rotator cuff disease. Ultimately, better understanding of the biologic mechanisms of early progression of rotator cuff disease may lead to clinical interventions to halt or slow this process and avoid the more advanced and often irreversible conditions of large tendon tears with muscle fatty atrophy.