All-Polyethylene Tibial Component in Unicompartmental Knee Arthroplasty Offers Excellent Survivorship and Clinical Outcomes at Short-Term Follow-Up: A Multicenter Retrospective Clinical Study.

Background and Objectives: The ten-year survivorship of unicompartmental knee arthroplasty (UKA) is up to 96%, varying from implants and hospitals; however, most of registry studies do not distinguish between metal-back (MB) tibial implants and all-polyethylene (AP) tibial implants. The aim of the present retrospective clinical study was to analyze the clinical outcomes and survivorship of medial and lateral UKA with a newly designed all-polyethylene tibial plateau at short-term follow-up. Materials and Methods: A retrospective analysis of prospectively collected consecutive patients who underwent medial or lateral UKA with AP tibial plateau was conducted, with a minimum follow-up of 1 year. Primary outcomes were clinical score (VAS, OKS, and KOOS) variations from baseline up to the latest follow-up. Secondary outcomes were Likert scale variations from baseline to the follow-up, evaluation of the influence of demographic factors (age and BMI) at the time of surgery on the clinical outcomes, and evaluation of revision rate up to the last follow-up. Results: The final study population included 99 knees. The mean VAS score for the medial group significantly decreased from 7.61 ± 1.65 (pre-intervention) to 2.74 ± 2.26 (post-intervention). Similar improvements were registered for the OKS as well, for both the medial group (from 22.5 ± 12.6 to 36.6 ± 10.6, with a delta of 14.11 (10.05 to 18.17)) and the lateral group (from 22.6 ± 12.6 to 36.9 ± 11.8, with a delta of 14.24 (8.65 to 19.83)). Moreover, all the KOOS subscales reported an amelioration, both in medial UKA and lateral UKA. Furthermore, a logistic regression of delta VAS was performed in relation to the other clinical questionnaires and the demographic factors. For both medial and lateral UKAs, no statistically significant correlation was found between the VAS scale regression and the demographic factors. The survival rate free from any revision of the cohort at the latest follow-up was 96.32%. Conclusions: All-polyethylene tibial component in unicompartmental knee arthroplasty demonstrates significant improvements in clinical scores and a low failure rate at short-term follow-up.

Is microfracture sufficient for high-tibial osteotomy, or should intra-articular hyaluronic acid and oral glucosamine-chondroitin be used as additional treatments?

BACKGROUND: This study aimed to compare the effects of microfracture (MF) versus intra-articular hyaluronic acid (HA) + oral glucosamine and chondroitin sulfate (GC) in addition to MF in patients with osteoarthritic knees who underwent medial open wedge high tibial osteotomy (MOWHTO) after an average follow-up of five years. METHODS: The study was designed retrospectively and included patients who underwent MOWHTO due to gonarthrosis, the MF method performed on these patients, and HA + GC treatments applied in addition to MF. Three groups consisting of 79 patients were formed: only HTO (Group 1), HTO + MF (Group 2), and HTO + MF + HA + GC (Group 3). The groups were compared using knee injury and osteoarthritis outcome score (KOOS), visual analog scale (VAS) for pain, and range of motion (ROM). The associations between the degree of correction and function and pain were evaluated. Additionally, the KOOS subparameters were compared between the groups. RESULTS: There were significant improvements in the postoperative KOOS and VAS scores in all three groups (p < 0.05). However, the ROM did not improve in Group 1. There was no significant difference in the postoperative KOOS, VAS, or ROM values ​​between Groups 2 and 3, but these values ​​were significantly better in Groups 2 and 3 than in Group 1 (p < 0.05). When the degree of correction increased, there were no significant positive changes in the postoperative KOOS or VAS score in Group 1, unlike in the other two groups (p < 0.05). In corrections of ≥ 10°, while there was no significant difference in the postoperative KOOS or VAS score ​​between Groups 2 and 3, these parameters significantly improved in these two groups compared to Group 1 (p < 0.05). Among the KOOS subparameters, pain and activities of daily living scores ​​were greater in Groups 2 and 3 than in Group 1 (p < 0.05). CONCLUSIONS: In MOWHTO, MF is a sufficient treatment method that improves the patient's clinical condition without requiring additional treatments such as HA and GC. LEVEL OF EVIDENCE: III, retrospective cohort study.

Adjusted planning based on the joint line convergence angle improves correction accuracy in the standing position after opening wedge high tibial osteotomy.

BACKGROUND: Postoperative change of the joint line convergence angle (JLCA) is known to be a factor affecting correction error in opening wedge high tibial osteotomy (OWHTO). The purpose of this study was to assess whether preoperative planning that considers change of the JLCA can achieve accurate correction in the standing position after OWHTO. METHODS: OWHTO was performed for 109 knees with osteoarthritis of the knee. The amount of angular correction was planned aiming to achieve mechanical valgus of 5° in 55 knees (conventional planning), and it was adjusted in 54 knees (adjusted planning) according to the preoperative JLCA as follows: not changed with JLCA ≤ 3°; decreased 1° with JLCA 4-6°; decreased 2° with JLCA 7-8°; and decreased 3° with JLCA ≥ 9°. The hip-knee-ankle (HKA) angle, JLCA, and medial proximal tibial angle (MPTA) were measured on standing long-leg radiographs. Correction error ≤ 2º was defined as the acceptable range, and correction error > 2º was defined as an outlier. RESULTS: The conventional planning group had a significantly greater postoperative HKA angle than the adjusted planning group (6.1º and 4.9º, respectively). The mean JLCA decreased from 4.8º to 2.6º in the conventional planning group and from 4.6º to 2.7º in the adjusted planning group. The conventional planning group had significantly greater postoperative MPTA than the adjusted planning group (96.2º and 94.7º, respectively). The rate of outliers with correction error > 2º was significantly lower in the adjusted planning group (9%) than in the conventional planning group (24%). The rate of the MPTA > 95º was significantly lower in the adjusted planning group (30%) than in the conventional planning group (69%). CONCLUSIONS: This study demonstrated that preoperative planning with adjustment of the correction angle according to the preoperative JLCA improved correction accuracy in the standing position after OWHTO.

Simultaneous bilateral open wedge high tibial osteotomy versus simultaneous bilateral unicompartmental knee arthroplasty in the treatment of bilateral medial knee osteoarthritis: a retrospective study of an average three-year follow-up.

OBJECTIVE: There is growing evidence that simultaneous bilateral open wedge high tibial osteotomy(SBOWHTO) and simultaneous bilateral unicompartmental knee arthroplasty(SBUKA) is an effective surgical treatment for bilateral medial knee osteoarthritis (MKOA). However, which intervention is more beneficial for bilateral MKOA patients remains unknown. Therefore, the aim of this study was to compare the effectiveness of these two strategies through early clinical outcomes, complication rates, and prosthetic survival. METHODS: The clinical data of 60 patients with bilateral MKOA admitted to the Affiliated Hospital of Qingdao University from January 2018 to December 2022 were retrospectively analyzed, and they were divided into SBOWHTO group (n = 28) and SBUKA group (n = 32) according to different treatment methods. Clinical relevant indexes, Hospital for Special Surgery (HSS) score, Knee Society Knee (KSS) score, range of motion(ROM), postoperative complications and prosthetic survival rate were compared between the two groups. RESULTS: Patients in the SBOWHTO group were followed up for 27 to 50 months, with an average of (37.18 ± 6.84) months. Patients in the SBUKA group were followed up for 24 to 59 months, with an average of (39.38 ± 9.74) months. There were no significant differences in postoperative KSS, HSS and ROM between SBOWHTO group and SBUKA group (p > 0.05). There was no significant difference in complication rate between the two groups (p = 0.721). There was no significant difference in prosthetic survival rate (p = 0.622) and prosthetic survival curve (χ2 = 0.546, p = 0.46) between the two groups. CONCLUSIONS: This study compared early clinical outcomes, complication rates, and prosthesis retention rates after SBOWHTO and SBUKA, and found that the early clinical benefits of SBOWHTO and SBUKA were comparable in patients with bilateral MKOA.

[Biomechanical study of three-dimensional printed filler block design in open wedge high tibial osteotomy].

The use of a filling block can improve the initial stability of the fixation plate in the open wedge high tibial osteotomy (OWHTO), and promote bone healing. However, the biomechanical effects of filling block structures and materials on OWHTO remain unclear. OWHTO anatomical filling block model was designed and built. The finite element analysis method was adopted to study the influence of six filling block structure designs and four different materials on the stress of the fixed plate, tibia, screw, and filling block, and the micro-displacement at the wedge gap of the OWHTO fixation system. After the filling block was introduced in the OWHTO, the maximum von Mises stress of the fixation plate was reduced by more than 30%, the maximum von Mises stress of the tibia decreased by more than 15%, and the lateral hinge decreased by 81%. When the filling block was designed to be filled in the posterior position of the wedge gap, the maximum von Mises stress of the fixation system was 97.8 MPa, which was smaller than other filling methods. The minimum micro-displacement of osteotomy space was -2.9 µm, which was larger than that of other filling methods. Compared with titanium alloy and tantalum metal materials, porous hydroxyapatite material could obtain larger micro-displacement in the osteotomy cavity, which is conducive to stimulating bone healing. The results demonstrate that OWHTO with a filling block can better balance the stress distribution of the fixation system, and a better fixation effect can be obtained by using a filling block filled in the posterior position. Porous HA used as the material of the filling block can obtain a better bone healing effect.

[Lateral open wedge tibial osteotomy for posttraumatic deformity]. / Tibiale laterale Open-wedge-Osteotomie bei posttraumatischer Deformität.

OBJECTIVE: Correction of pseudoinstability and tibial malalignment by re-establishment of the pretraumatic tibial axis. INDICATIONS: Posttraumatic valgus malalignment accompanied by pseudoinstability. CONTRAINDICATIONS: Infections, significant inhibition of movement and multidirectional ligament instability. SURGICAL TECHNIQUE: Standard anterolateral approach to the proximal tibial head. Lateral open wedge high tibial osteotomy above (supra) the tibiofibular joint and opening until the pseudoinstability of the lateral collateral ligament is levelled. POSTOPERATIVE MANAGEMENT: Partial weight bearing for 4 weeks, after radiological control full body weight loading is allowed. Implant removal after full bony consolidation. RESULTS: There is limited evidence in the current literature but the available results show good results in 70% of the cases in long-term follow-up.

Histological and scanning electron microscopy investigation of the effects of titanium surface modifications on osseointegration in rabbits.

This study aimed to compare the novel Estas Medical Anodization (EMA) surface treatment technique with the techniques commonly used in the literature and to examine their effects on osteointegration in the rabbit tibia. A total of 24 rabbits used in this study were divided into 3 groups, with 8 rabbits in each group. Using both tibias of all rabbits in the study, screws belonging to the control group were placed in the left tibia, and the right tibia belonging to the experimental group were placed. In the first 8 rabbits, a single experimental group in the right tibia were used; in the second 8 rabbits, 2 different experimental groups in the right tibia were used; and in the last 8 rabbits, 2 different experimental groups in the right tibia were used. Thus, 5 different experimental groups with 8 screws in each group and a separate control group were formed for each of them. EMA-treated surfaces were named 200-800 nm iris oxidation and 800-1200 nm gray oxidation according to the TiO2 layer thickness. Group 1 was implanted with mini-screws prepared with chemical etching+EMA iris oxidation, while group 2 was implanted with sandblasted, large-grit and acid-etched (SLA) mini screws treated with EMA gray oxidation. Group 3 was implanted with mini-screws treated with EMA gray oxidation, group 4 was implanted with mini-screws treated with chemical etching+micro-arc oxidation, and group 5 was implanted with mini-screws treated with chemical etching+EMA gray oxidation. The control group was implanted with mini-screws prepared with pure titanium. At the end of 6 weeks, osseointegration percentages were calculated and compared using histological and scanning electron microscope (SEM) analyses. The histological results confirmed the increase in osseointegration percentages in all experimental groups compared to those that received pure titanium implants (P values control group vs group 1=.005, control group vs group 2, 3, 4, 5=.001). The comparison between the groups revealed that the chemical etching+EMA gray oxidation modification technique (group 5) significantly increased osseointegration compared to the SLA+EMA gray oxidation technique (group 5 vs group 2 P=.016) and the chemical etching+EMA iris oxidation technique (group 5 vs group 1 Pp=.001). The EMA gray oxidation technique (group 3) significantly increased osseointegration compared to the chemical etching+EMA iris oxidation technique (group 1) (group 3 vs group 1 P=.043). The results of the SEM analysis showed that osseointegration was significantly increased in all experimental groups compared to that in the pure titanium (control) group (P values control group vs group 1, 2, 3=.001, control group vs Group 4,5=.006). The mean osseointegration percentage in the experimental groups was the highest in group 5, followed by group 4, group 3 and group 1 equally, and group 2. However, the differences among the experimental were not significant (group 1, group 2, group 3, group 4 vs group 5 P=.408). The EMA titanium surface modification techniques we developed significantly increased osseointegration compared to the pure titanium surface. The EMA gray oxidation technique seems to result in higher osseointegration rates than the EMA iris oxidation technique, and similar rates can be found with the SLA and chemical etching techniques. N/A.

[High tibial osteotomy on varus knee osteoarthritis with medial meniscus posterior root injury].

OBJECTIVE: To explore clinical effect of distal tibial tubercle-high tibial osteotomy (DTT-HTO) in treating knee osteoarthritis (KOA) with medial meniscus posterior root tear (MMPRT). METHODS: A retrospective analysis was performed on 21 patients with varus KOA with MMPRT from May 2020 to December 2021, including 3 males and 18 females, aged from 49 to 75 years old with an average of (63.81±6.56) years old, the courses of disease ranged from 0.5 to 18.0 years with an average of(5.9±4.2) years, and 4 patients with grade Ⅱ, 14 patients with grade Ⅲ, and 3 patients with grade Ⅳ according to Kellgren-Lawrence;14 patients with type 1 and 7 patients with type 2 according to MMPRT damage classification. The distance of medial meniscusextrusion (MME) and weight-bearing line ratio (WBLR) of lower extremity were compared before and 12 months after operation. Visual analogue scale (VAS), Western Ontarioand and McMaster Universities (WOMAC) osteoarthritis index, and Lysholm knee score were used to evaluate knee pain and functional improvement before operation, 1, 6 and 12 months after operation, respectively. RESULTS: Twenty-one patients were followed up for 12 to 18 months with an average of (13.52±1.72) months. MME distance was improved from (4.99±1.05) mm before operation to (1.87±0.76) mm at 12 months after operation (P<0.05). WBLR was increased from (15.49±7.04)% before operation to (62.71±2.27)% at 12 months after operation (P<0.05). VAS was decreased from (7.00±1.14) before operation to (2.04±0.80), (0.90±0.62) and (0.61±0.50) at 1, 6 and 12 months after operation. WOMAC were decreased from preoperative (147.90±9.88) to postoperative (103.43±8.52), (74.00±9.54) and (47.62±9.53) at 1, 6 and 12 months, and the difference were statistically significant (P<0.05). Lysholm scores were increased from (46.04±7.34) before oepration to (63.19±8.93), (81.10±6.41) and (89.29±3.04) at 1, 6 and 12 months after operation(P<0.05). CONCLUSION: For the treatment of varus KOA with MMPRT, DTT-HTO could reduce medial meniscus protrusion distance, improve the ratio of lower limb force line, and effectively reduce knee pain and improve knee joint function.

Analysis of correlation between medial joint line change and lower limb coronal alignment after Oxford unicompartmental knee arthroplasty.

BACKGROUND: Lower limb coronal alignment was thought to be a predictive factor for Unicompartmental Knee Arthroplasty (UKA) result. The tibial bony resection and implant position lead to joint line change postoperatively. Analysis was done to find out the correlation between these factors. METHODS: From 2019 to 2021, 90 medial Oxford UKA were implanted by a single surgeon. Hip Knee Ankle Angle (HKAA), Lateral Distal Femoral Angle (LDFA), Medial Proximal Tibial Angle (MPTA), and intraoperative bony resection thickness were measured. The medial joint line change was calculated. The correlation between joint line change and alignment change was evaluated. RESULTS: The mean tibial resection thickness was 4.3 mm. The mean tibial joint line was elevated by 2.3 mm, while the mean femoral joint line proximalized by 0.8 mm. HKAA changed from 8.4° varus preoperatively to 3.6° varus postoperatively. LDFA changed from 89.0° to 86.7°. MPTA changed from 85.6° to 86.6°. Preoperative HKAA showed a strong correlation with postoperative HKAA (p < 0.001), and preoperative MPTA showed a positive correlation with postoperative HKAA (p < 0.001). While preoperative LDFA had a negative correlation with postoperative HKAA (p < 0.001). The femoral joint line change and LDFA change had a significant correlation with HKAA change (p < 0.05). CONCLUSION: The change of joint line had no correlation with postoperative HKAA in Oxford UKA. Preoperative HKAA strongly correlated with postoperative HKAA; while preoperative smaller LDFA and larger MPTA had a moderate correlation with postoperative HKAA. The femoral joint line change and LDFA change had a weak to moderate correlation with HKAA change.

Management of Progressive Unilateral Tibia Vara in a 3-Year-Old Child with Focal Fibrocartilaginous Defect: A Case Report.

CASE: A 3-year-old boy with unilateral tibia vara was diagnosed with focal fibrocartilaginous dysplasia (FFCD) of the left proximal tibia. Because of progressive deformity with intercondylar distance of 9 cm and tibia metaphyseal-diaphyseal angle of 28°, the child was treated with curettage of the lesion and lateral proximal tibia hemiepiphysiodesis with 8 plates. The deformity was corrected within 12 months, the implant was removed, and the child is being followed up till skeletal maturity. CONCLUSION: Curettage of the lesion and guided growth with an 8-plate is a viable treatment method for FFCD of the proximal tibia with progressive tibia vara deformity.

Four-Direction Procedures Involving Tibial Tubercle Osteotomy for Habitual Dislocation of the Patella: A Case Report.

CASE: A 22-year-old man with habitual dislocation of the patella (HDP), characterized by lateral dislocation in flexion with spontaneous relocation with extension, presented with right knee pain and inability to actively extend. Imaging revealed lateral patellar dislocation, flat articular surface of the patella, and trochlear dysplasia. His symptoms persisted despite physical therapy. A 4-directional patellar stabilization surgery, incorporating lateral release, medial tibial tuberosity osteotomy, quadriceps muscle lengthening, and medial patellofemoral ligament reconstruction, was performed, with significant improvement in pain and function postoperatively. CONCLUSION: The procedure could be feasible in cases of severe HDP when conservative measures failed to relieve the patient's symptoms.

Open Bone Augmentation Solutions for the Failed Shoulder Stabilization.

Utilizing fresh distal tibia allograft in anterior glenoid reconstruction has emerged as a highly advantageous approach in addressing instances of failed anterior shoulder stabilization with glenoid bone loss. This procedure offers several benefits, including the absence of donor-site morbidity, restoration of significant glenoid defects, reestablishment of joint congruity with the humeral head, restoration of glenoid biomechanics, and the addition of cartilage to the glenoid. Furthermore, it provides a robust and reliable alternative for managing failed stabilization procedures, leading to improved clinical outcomes and a high graft healing rate, while maintaining a low occurrence of recurrent instability.

Impact of fractured tibia implant fixation devices on bone stiffness during bending test.

This study focuses on evaluating the failure resistance of a previously reduced tibia with internal fixation implants as PLate (PL) or InterMedullary Nail (IMN), subjected later to a tibial lateral trauma. To replicate this type of trauma, which can be caused by a road accident, a three-point bending test is considered using experimental tests and numerical simulations. The withstand evaluation of the tibia-PL and tibia-IMN structures was conducted by following the load transfer through, the bone and the used implants. The analysis, up to tibia failure, required the use of an elasto-plastic behavior law coupled to damage. The model parameters were identified using experimental tests. Il was shown that the tibia-IMN structure provided a bending resistant load up to three-times higher than the tibia-PL. In fact, the used screws for plate fixation induced a high level of stress in the vicinity of threaded region, leading to a crack initiation and a damage propagation. However, in tibia-IMN structure the highest stress was generated in the trapped zone between the loader and the nail, promoting crack formation. From a biomechanical point of view, the structure with IMN is safer than the structure with PL, whose fixation induces earlier damage in bone.

The Impact of Adding a Tibial Tubercle Osteotomy to Medial Patellofemoral Ligament Reconstruction in the Treatment of Patellar Instability.

BACKGROUND: An isolated medial patellofemoral ligament (MPFL) reconstruction (MPFLR) has been demonstrated to be an effective treatment option in the prevention of patellar instability, but there is growing support for performing a tibial tubercle osteotomy (TTO) in patients with an elevated tibial tubercle-trochlear groove distance. The purpose of this study was to evaluate the impact of adding a TTO to MPFLR on patient reported outcomes. METHODS: A retrospective review of patients who underwent MPFLR with or without TTO with a minimum of 12-month follow-up was performed. Patients in both groups were matched based on age, sex, and follow-up time. Recurrent instability (including re-dislocation and subluxation), visual analog scale (VAS) for pain score, Kujala score, and satisfaction were evaluated. RESULTS: There were 59 patients who underwent MPFLR with concomitant TTO performed at our institution and met our inclusion and exclusion criteria. These patients were then matched to patients undergoing isolated MPFLR based on demographics and follow-up time. The mean age was 25.0, 76.3% were female, and the mean follow-up time was 49 months. There was a significant difference in mean tibial tubercle-trochlear groove distance (19.8 ± 3.9 vs. 14.1 ± 2.8) between groups. There was no significant difference in VAS (1.48 ± 2.0 vs. 1.49 ± 2.1, p = 0.972), satisfaction (86.1% ± 24.2% vs. 81.2% ± 27.9, p = 0.311), or revision surgeries (10.2% vs. 10.2%) between groups. CONCLUSION: There was a low complication rate, excellent patient reported outcomes, and a low rate of recurrent patellar instability following TTO and MPFLR with allograft.

Vascularized Femoral Myo-Periosteal Graft for Congenital Pseudarthrosis of the Tibia: A Case Report.

Pure vascularized periosteal transplants have been shown to be extremely effective at achieving rapid bone healing in children with biologically complex non-union. Free tibial and fibular periosteal transplants are generally indicated when large periosteal flaps are necessary. We report using a vascularized femoral myo-periosteal graft (VFMPG) to treat distal tibial osteotomy non-union in a six-year-old boy with congenital pseudarthrosis of the tibia. The graft consisted of a 9 cm myo-periosteal flap (after 50% of elastic retraction) that incorporated the vastus intermedius muscle and diaphyseal femoral periosteum nourished by the descending branch of the lateral circumflex femoral vessels. Plantaris medialis was used as a recipient vessel. Healing occurred 10 weeks after surgery. The patient resumed gait and sports activity without orthosis. No donor or recipient site complications occurred 17 months after surgery. Employing a VFMPG might be an alternative to other free or large vascularized periosteal flaps currently in use for complex pediatric non-unions.

Titanium micro-nano textured surface with strontium incorporation improves osseointegration: an in vivo and in vitro study.

OBJECTIVES: This study aimed to investigate the osseointegration of titanium (Ti) implants with micro-nano textured surfaces functionalized with strontium additions (Sr) in a pre-clinical rat tibia model. METHODOLOGY: Ti commercially pure (cp-Ti) implants were installed bilaterally in the tibia of 64 Holtzman rats, divided into four experimental groups (n=16/group): (1) Machined surface - control (C); (2) Micro-nano textured surface treatment (MN); (3) Micro-nano textured surface with Sr2+ addition (MNSr); and (4) Micro-nano textured surface with a higher complementary addition of Sr2+ (MNSr+). In total, two experimental euthanasia periods were assessed at 15 and 45 days (n=8/period). The tibia was subjected to micro-computed tomography (µ-CT), histomorphometry with the EXAKT system, removal torque (TR) testing, and gene expression analysis by PCR-Array of 84 osteogenic markers. Gene expression and protein production of bone markers were performed in an in vitro model with MC3T3-E1 cells. The surface characteristics of the implants were evaluated by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and laser scanning confocal microscopy. RESULTS: SEM, confocal, and EDS analyses demonstrated the formation of uniform micro-nano textured surfaces in the MN group and Sr addition in the MNSr and MNSr+ groups. TR test indicated greater osseointegration in the 45-day period for treated surfaces. Histological analysis highlighted the benefits of the treatments, especially in cortical bone, in which an increase in bone-implant contact was found in groups MN (15 days) and MNSr (45 days) compared to the control group. Gene expression analysis of osteogenic activity markers showed modulation of various osteogenesis-related genes. According to the in vitro model, RT-qPCR and ELISA demonstrated that the treatments favored gene expression and production of osteoblastic differentiation markers. CONCLUSIONS: Micro-nano textured surface and Sr addition can effectively improve and accelerate implant osseointegration and is, therefore, an attractive approach to modifying titanium implant surfaces with significant potential in clinical practice.

Neglected errors in ligament reconstruction surgery may increase graft-tunnel mismatch: A biomechanical study.

Tunnel widening is a frequent problem following arthroscopic ligament reconstruction surgery that may primarily arise from a graft-tunnel mismatch caused by errors in surgical instruments and methods. The present study aimed to observe the influence of current surgical instruments and methods on graft-tunnel matching. We established an in vitro model using porcine Achilles tendons and tibias, and compared traditional surgical instruments (control group) with custom instruments (experimental group). Graft measurements, bone-tunnel creation, and measurements of the maximum pullout force of the graft from the bone tunnel were performed. Results indicated that the measuring gauge developed by our research group (capable of accurate measurement of graft diameters) may mitigate errors arising from graft-diameter measurement using traditional measuring cylinders. Therefore, errors caused by current surgical instruments and surgical methods led to an increase in graft-tunnel mismatches. The degree of mismatch was greater at the tibial end than at the femoral end.

A novel model of autologous tooth transplantation for the study of nerve recruitment.

BACKGROUND: Limited treatment options exist for damaged nerves and despite impressive advances in tissue engineering, scientists and clinicians have yet to fully replicate nerve development and recruitment. Innervation is a critical feature for normal organ function. While most organs are innervated prior to birth, a rare example of postnatal nerve recruitment occurs in the natural development of secondary teeth during adolescence. Many animals undergo postnatal shedding of deciduous teeth with development and eruption of secondary teeth, a process requiring recruitment of nerve and vasculature to each tooth pulp for viability. Here, the investigators created a novel model for the study of postnatal innervation by exploiting the natural phenomenon of tooth-driven nerve recruitment. METHODS: The investigators theorized that developing teeth possess a special capacity to induce innervation which could be harnessed in a clinical setting for nerve regeneration, and hyptothesized that a transplant model could be created to capture this phenomenon. In this descriptive study, a rat model of autologous tooth transplantation and de novo nerve recruitment was developed by surgically transferring whole developing molars to the autologous tibia. RESULTS: Downstream histological analysis performed 6 to 14 weeks after surgery demonstrated integration of molar into tibia in 81% of postoperative rats, with progressive pulpal expression of nerve marker ß-tubulin III suggestive of neuronal recruitment. CONCLUSIONS: These findings provide a novel model for the study of organ transplantation and support the theory that developing dental tissues may retain nerve-inductive properties postnatally.

Walking Ankle Biomechanics of Individuals With Transtibial Amputations Using a Prescribed Prosthesis and a Portable Bionic Prosthesis Under Myoelectric Control.

Individuals with transtibial amputation can activate residual limb muscles to volitionally control robotic ankle prostheses for walking and postural control. Most continuous myoelectric ankle prostheses have used a tethered, pneumatic device. The Open Source Leg allows for myoelectric control on an untethered electromechanically actuated ankle. To evaluate continuous proportional myoelectric control on the Open Source Ankle, we recruited five individuals with transtibial amputation. Participants walked over ground with an experimental powered prosthesis and their prescribed passive prosthesis before and after multiple powered device practice sessions. Participants averaged five hours of total walking time. After the final testing session, participants indicated their prosthesis preference via questionnaire. Participants tended to increase peak ankle power after practice (powered 0.80 ± 1.02 W/kg and passive 0.39 ± 0.31 W/kg). Additionally, participants tended to generate greater ankle work with the powered prosthesis compared to their passive device ( 0.13 ± .15 J/kg increase). Although work and peak power generation were not statistically different between the two prostheses, participants preferred walking with the prosthesis under myoelectric control compared to the passive prosthesis. These results indicate individuals with transtibial amputation learned to walk with an untethered powered prosthesis under continuous myoelectric control. Four out 5 participants generated larger magnitudes in peak power compared to their passive prosthesis after practice sessions. An additional important finding was participants chose to walk with peak ankle powers about half of what the powered prosthesis was capable of based on mechanical testing.