Restoration of proximal medial femoral support is the keystone in the treatment of intertrochanteric fractures. None of the available implants are effective in constructing the medial femoral support. Medial sustainable nail (MSN-II) is a novel cephalomedullary nail designed for this. In this study, biomechanical difference between MSN-II and proximal femoral nail anti-rotation (PFNA-II) was compared to determine whether or not MSN-II can effectively reconstruct the medial femoral support. A total of 36 synthetic femur models with simulated intertrochanteric fractures without medial support (AO/OTA 31-A2.3) were assigned to two groups with 18 specimens each for stabilization with MSN-II or PFNA-II. Each group was further divided into three subgroups of six specimens according to different experimental conditions respectively as follows: axial loading test; static torsional test; and cyclic loading test.Aims
Methods
Many biomechanical studies have shown that the weakest biomechanical point of a rotator cuff repair is the suture-tendon interface at the medial row. We developed a novel double rip-stop (DRS) technique to enhance the strength at the medial row for rotator cuff repair. The objective of this study was to evaluate the biomechanical properties of the DRS technique with the conventional suture-bridge (SB) technique and to evaluate the biomechanical performance of the DRS technique with medial row knots. A total of 24 fresh-frozen porcine shoulders were used. The infraspinatus tendons were sharply dissected and randomly repaired by one of three techniques: SB repair (SB group), DRS repair (DRS group), and DRS with medial row knots repair (DRSK group). Specimens were tested to failure. In addition, 3 mm gap formation was measured and ultimate failure load, stiffness, and failure modes were recorded.Aims
Methods
This exploratory randomized controlled trial (RCT) aimed to determine the splint-related outcomes when using the novel biodegradable wood-composite splint (Woodcast) compared to standard synthetic fibreglass (Dynacast) for the immobilization of undisplaced upper limb fractures in children. An exploratory RCT was performed at a tertiary paediatric referral hospital between 1 June 2018 and 30 September 2019. The intention-to-treat population consisted of 170 patients (mean age 8.42 years (SD 3.42); Woodcast (WCG), n = 84, 57 male (67.9%); Dynacast (DNG), n = 86, 58 male (67.4%)). Patients with undisplaced upper limb fractures were randomly assigned to WCG or DNG treatment groups. Primary outcome was the stress stability of the splint material, defined as absence of any deformations or fractures within the splint during study period. Secondary outcomes included patient satisfaction and medical staff opinion. Additionally, biomechanical and chemical analysis of the splint samples was carried out.Aims
Methods
Evaluate if treating an unstable femoral neck fracture with a locking plate and spring-loaded telescoping screw system would improve construct stability compared to gold standard treatment methods. A 31B2 Pauwels’ type III osteotomy with additional posterior wedge was cut into 30 fresh-frozen femur cadavers implanted with either: three cannulated screws in an inverted triangle configuration (CS), a sliding hip screw and anti-rotation screw (SHS), or a locking plate system with spring-loaded telescoping screws (LP). Dynamic cyclic compressive testing representative of walking with increasing weight-bearing was applied until failure was observed. Loss of fracture reduction was recorded using a high-resolution optical motion tracking system.Aims
Methods
Fixation of osteoporotic proximal humerus fractures remains challenging even with state-of-the-art locking plates. Despite the demonstrated biomechanical benefit of screw tip augmentation with bone cement, the clinical findings have remained unclear, potentially as the optimal augmentation combinations are unknown. The aim of this study was to systematically evaluate the biomechanical benefits of the augmentation options in a humeral locking plate using finite element analysis (FEA). A total of 64 cement augmentation configurations were analyzed using six screws of a locking plate to virtually fix unstable three-part fractures in 24 low-density proximal humerus models under three physiological loading cases (4,608 simulations). The biomechanical benefit of augmentation was evaluated through an established FEA methodology using the average peri-screw bone strain as a validated predictor of cyclic cut-out failure.Aims
Methods
To devise a method to quantify and optimize tightness when inserting cortical screws, based on bone characterization and screw geometry. Cortical human cadaveric diaphyseal tibiae screw holes (n = 20) underwent destructive testing to firstly establish the relationship between cortical thickness and experimental stripping torque (Tstr), and secondly to calibrate an equation to predict Tstr. Using the equation’s predictions, 3.5 mm screws were inserted (n = 66) to targeted torques representing 40% to 100% of Tstr, with recording of compression generated during tightening. Once the target torque had been achieved, immediate pullout testing was performed.Aims
Methods
Arthrofibrosis is a relatively common complication after joint injuries and surgery, particularly in the knee. The present study used a previously described and validated rabbit model to assess the biomechanical, histopathological, and molecular effects of the mast cell stabilizer ketotifen on surgically induced knee joint contractures in female rabbits. A group of 12 skeletally mature rabbits were randomly divided into two groups. One group received subcutaneous (SQ) saline, and a second group received SQ ketotifen injections. Biomechanical data were collected at eight, ten, 16, and 24 weeks. At the time of necropsy, posterior capsule tissue was collected for histopathological and gene expression analyses (messenger RNA (mRNA) and protein).Aims
Methods
This study investigated the biomechanical performance of decellularized porcine superflexor tendon (pSFT) grafts of varying diameters when utilized in conjunction with contemporary ACL graft fixation systems. This aimed to produce a range of ‘off-the-shelf’ products with predictable mechanical performance, depending on the individual requirements of the patient. Decellularized pSFTs were prepared to create double-bundle grafts of 7 mm, 8 mm, and 9 mm diameter. Femoral and tibial fixation systems were simulated utilizing Arthrex suspension devices and interference screws in bovine bone, respectively. Dynamic stiffness and creep were measured, followed by ramp to failure from which linear stiffness and load at failure were measured. The mechanisms of failure were also recorded.Objectives
Methods
Periprosthetic femoral fractures (PFFs) have a higher incidence with cementless stems. The highest incidence among various cementless stem types was observed with double-wedged stems. Short stems have been introduced as a bone-preserving alternative with a higher incidence of PFF in some studies. The purpose of this study was a direct load-to-failure comparison of a double-wedged cementless stem and a short cementless stem in a cadaveric fracture model. Eight hips from four human cadaveric specimens (age mean 76 years (60 to 89)) and eight fourth-generation composite femurs were used. None of the cadaveric specimens had compromised quality (mean T value 0.4 (-1.0 to 5.7)). Each specimen from a pair randomly received either a double-wedged stem or a short stem. A materials testing machine was used for lateral load-to-failure test of up to a maximal load of 5000 N.Objectives
Methods
Screw plugs have been reported to increase the fatigue strength of stainless steel locking plates. The objective of this study was to examine and compare this effect between stainless steel and titanium locking plates. Custom-designed locking plates with identical structures were fabricated from stainless steel and a titanium alloy. Three types of plates were compared: type I unplugged plates; type II plugged plates with a 4 Nm torque; and type III plugged plates with a 12 Nm torque. The stiffness, yield strength, and fatigue strength of the plates were investigated through a four-point bending test. Failure analyses were performed subsequently.Objectives
Methods
The medial malleolus, once believed to be the primary stabilizer of the ankle, has been the topic of conflicting clinical and biomechanical data for many decades. Despite the relevant surgical anatomy being understood for almost 40 years, the optimal treatment of medial malleolar fractures remains unclear, whether the injury occurs in isolation or as part of an unstable bi- or trimalleolar fracture configuration. Traditional teaching recommends open reduction and fixation of medial malleolar fractures that are part of an unstable injury. However, there is recent evidence to suggest that nonoperative management of well-reduced fractures may result in equivalent outcomes, but without the morbidity associated with surgery. This review gives an update on the relevant anatomy and classification systems for medial malleolar fractures and an overview of the current literature regarding their management, including surgical approaches and the choice of implants. Cite this article: Abstract
Elevated proximal tibial bone strain may cause unexplained pain, an important cause of unicompartmental knee arthroplasty (UKA) revision. This study investigates the effect of tibial component alignment in metal-backed (MB) and all-polyethylene (AP) fixed-bearing medial UKAs on bone strain, using an experimentally validated finite element model (FEM). A previously experimentally validated FEM of a composite tibia implanted with a cemented fixed-bearing UKA (MB and AP) was used. Standard alignment (medial proximal tibial angle 90°, 6° posterior slope), coronal malalignment (3°, 5°, 10° varus; 3°, 5° valgus), and sagittal malalignment (0°, 3°, 6°, 9°, 12°) were analyzed. The primary outcome measure was the volume of compressively overstrained cancellous bone (VOCB) < -3000 µε. The secondary outcome measure was maximum von Mises stress in cortical bone (MSCB) over a medial region of interest.Objectives
Methods
The properties of impacted morsellised bone graft (MBG) in revision total knee arthroplasty (TKA) were studied in 12 horses. The left hind metatarsophalangeal joint was replaced by a human TKA. The horses were then randomly divided into graft and control groups. In the graft group, a unicondylar, lateral uncontained defect was created in the third metatarsal bone and reconstructed using autologous MBG before cementing the TKA. In the control group, a cemented TKA was implanted without the bone resection and grafting procedure. After four to eight months, the animals were killed and a
Options for the treatment of intra-articular ligament injuries are limited, and insufficient ligament reconstruction can cause painful joint instability, loss of function, and progressive development of degenerative arthritis. This study aimed to assess the capability of a biologically enhanced matrix material for ligament reconstruction to withstand tensile forces within the joint and enhance ligament regeneration needed to regain joint function. A total of 18 New Zealand rabbits underwent bilateral anterior cruciate ligament reconstruction by autograft, FiberTape, or FiberTape-augmented autograft. Primary outcomes were biomechanical assessment (n = 17), microCT (µCT) assessment (n = 12), histological evaluation (n = 12), and quantitative polymerase chain reaction (qPCR) analysis (n = 6).Aims
Materials and Methods
Plating displaced proximal humeral fractures is associated with a high rate of screw perforation. Dynamization of the proximal screws might prevent these complications. The aim of this study was to develop and evaluate a new gliding screw concept for plating proximal humeral fractures biomechanically. Eight pairs of three-part humeral fractures were randomly assigned for pairwise instrumentation using either a prototype gliding plate or a standard PHILOS plate, and four pairs were fixed using the gliding plate with bone cement augmentation of its proximal screws. The specimens were cyclically tested under progressively increasing loading until perforation of a screw. Telescoping of a screw, varus tilting and screw migration were recorded using optical motion tracking.Aims
Methods
The aim of this study was to investigate the effect of a posterior
malleolar fragment (PMF), with <
25% ankle joint surface, on
pressure distribution and joint-stability. There is still little
scientific evidence available to advise on the size of PMF, which
is essential to provide treatment. To date, studies show inconsistent
results and recommendations for surgical treatment date from 1940. A total of 12 cadaveric ankles were assigned to two study groups.
A trimalleolar fracture was created, followed by open reduction
and internal fixation. PMF was fixed in Group I, but not in Group
II. Intra-articular pressure was measured and cyclic loading was
performed.Aims
Materials and Methods
The traditional transosseus flexor hallucis longus (FHL) tendon
transfer for patients with Achilles tendinopathy requires two incisions
to harvest a long tendon graft. The use of a bio-tenodesis screw
enables a short graft to be used and is less invasive, but lacks
supporting evidence about its biomechanical behaviour. We aimed,
in this study, to compare the strength of the traditional transosseus
tendon-to-tendon fixation with tendon-to-bone fixation using a tenodesis
screw, in cyclical loading and ultimate load testing. Tendon grafts were undertaken in 24 paired lower-leg specimens
and randomly assigned in two groups using fixation with a transosseus
suture (suture group) or a tenodesis screw (screw group). The biomechanical
behaviour was evaluated using cyclical and ultimate loading tests.
The Student’s Aims
Materials and Methods
The success of anterior cruciate ligament reconstruction (ACLR)
depends on osseointegration at the graft-tunnel interface and intra-articular
ligamentization. Our aim was to conduct a systematic review of clinical
and preclinical studies that evaluated biological augmentation of
graft healing in ACLR. In all, 1879 studies were identified across three databases.
Following assessment against strict criteria, 112 studies were included
(20 clinical studies; 92 animal studies). Aims
Materials and Methods
