Objectives. 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. Methods. 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. Results. Mean
Aims. A growing number of fractures progress to delayed or nonunion, causing significant morbidity and socioeconomic impact. Localized delivery of stem cells and subcutaneous parathyroid hormone (PTH) has been shown individually to accelerate bony regeneration. This study aimed to combine the therapies with the aim of upregulating fracture healing. Methods. A 1.5 mm femoral osteotomy (delayed union model) was created in 48 female juvenile Wistar rats, aged six to nine months, and stabilized using an external fixator. At day 0, animals were treated with intrafracture injections of 1 × 10. 6. cells/kg bone marrow mesenchymal stem cells (MSCs) suspended in fibrin, daily subcutaneous injections of high (100 μg/kg) or low (25 μg/kg) dose PTH 1-34, or a combination of PTH and MSCs. A group with an empty gap served as a control. Five weeks post-surgery, the femur was excised for radiological, histomorphometric, micro-CT, and mechanical analysis. Results. Combination therapy treatment led to increased callus formation compared to controls. In the high-dose combination group there was significantly greater mineralized tissue volume and trabecular parameters compared to controls (p = 0.039). This translated to significantly improved stiffness (and ultimate
Aims. 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. Methods. 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
Aims. Rotator cuff (RC) tears are common musculoskeletal injuries which often require surgical intervention. Noninvasive pulsed electromagnetic field (PEMF) devices have been approved for treatment of long-bone fracture nonunions and as an adjunct to lumbar and cervical spine fusion surgery. This study aimed to assess the effect of continuous PEMF on postoperative RC healing in a rat RC repair model. Methods. A total of 30 Wistar rats underwent acute bilateral supraspinatus tear and repair. A miniaturized electromagnetic device (MED) was implanted at the right shoulder and generated focused PEMF therapy. The animals’ left shoulders served as controls. Biomechanical, histological, and bone properties were assessed at three and six weeks. Results. Extension of the tendon from preload to the maximum
Operative fixation is the treatment of choice for a rupture of the distal tendon of biceps. A variety of techniques have been described including transosseous sutures and suture anchors. The poor quality of the bone of the radial tuberosity might affect the
Objectives. 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. Methods. 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
Previously, we showed that case-specific non-linear
finite element (FE) models are better at predicting the load to failure
of metastatic femora than experienced clinicians. In this study
we improved our FE modelling and increased the number of femora
and characteristics of the lesions. We retested the robustness of
the FE predictions and assessed why clinicians have difficulty in
estimating the
We compared time-dependent changes in the biomechanical properties of single-and double-row repair of a simulated acute tear of the rotator cuff in rabbits to determine the effect of the fixation techniques on the healing process. A tear of the supraspinatus tendon was created in 80 rabbits which were separated into two equal groups. A single-row repair with two suture anchors was conducted in group 1 and a double-row repair with four suture anchors in group 2. A total of ten intact contralateral shoulder joints was used as a control group. Biomechanical testing was performed immediately post-operatively and at four and eight weeks, and histological analysis at four and eight weeks. The mean
Aims. 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. Materials and Methods. 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). Results. At eight weeks, FiberTape alone or FiberTape-augmented autograft demonstrated increased biomechanical stability compared with autograft regarding ultimate
A total of 20 pairs of fresh-frozen cadaver femurs were assigned to four alignment groups consisting of relative varus (10° and 20°) and relative valgus (10° and 20°), 75 composite femurs of two neck geometries were also used. In both the cadaver and the composite femurs, placing the component in 20° of valgus resulted in a significant increase in
We tested four types of surgical
repair for
Aims. 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. Materials and Methods. 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 t-test was performed to assess statistically significant
differences in bone mineral density (BMD), displacement, the slope
of the load-displacement curves, and
We measured the initial fixation strength of a new graft, bone-hamstring-bone (BHB), for reconstruction of the anterior cruciate ligament (ACL) in 79 porcine knees and compared it with that of the normal porcine ACL and of the bone-patellar tendon-bone (BPB) graft. All specimens were subjected to ultimate
Aims. This study aimed to establish the optimal fixation methods for calcaneal tuberosity avulsion fractures with different fragment thicknesses in a porcine model. Methods. A total of 36 porcine calcanea were sawed to create simple avulsion fractures with three different fragment thicknesses (5, 10, and 15 mm). They were randomly fixed with either two suture anchors or one headless screw. Load-to-failure and cyclic loading tension tests were performed for the biomechanical analysis. Results. This biomechanical study predicts that headless screw fixation is a better option if fragment thickness is over 15 mm in terms of the comparable peak
Objectives. All-suture anchors are increasingly used in rotator cuff repair procedures. Potential benefits include decreased bone damage. However, there is limited published evidence for the relative strength of fixation for all-suture anchors compared with traditional anchors. Materials and Methods. A total of four commercially available all-suture anchors, the ‘Y-Knot’ (ConMed), Q-FIX (Smith & Nephew), ICONIX (Stryker) and JuggerKnot (Zimmer Biomet) and a traditional anchor control TWINFIX Ultra PK Suture Anchor (Smith & Nephew) were tested in cadaveric human humeral head rotator cuff repair models (n = 24). This construct underwent cyclic loading applied by a mechanical testing rig (Zwick/Roell). Ultimate
The August 2024 Trauma Roundup360 looks at: Does topical vancomycin prevent fracture-related infections in closed fractures undergoing open reduction and internal fixation? A randomized controlled trial; Is postoperative splinting advantageous after upper limb fracture surgery?; Does suprapatellar nailing resolve knee pain?; Locking versus non-locking plate fixation in comminuted talar neck fractures: a biomechanical study using cadaveric specimens; Revolutionizing recovery metrics: PROMIS versus SMFA in orthopaedic trauma care; Dorsal hook plating of patella fractures: reliable fixation and satisfactory outcomes; The impact of obesity on subtrochanteric femur fracture outcomes; Low-dose NSAIDs (ketorolac) and cytokine modulation in orthopaedic polytrauma: a detailed analysis.
The December 2023 Trauma Roundup360 looks at: Distal femoral arthroplasty: medical risks under the spotlight; Quads repair: tunnels or anchors?; Complex trade-offs in treating severe tibial fractures: limb salvage versus primary amputation; Middle-sized posterior malleolus fractures – to fix?; Bone transport through induced membrane: a randomized controlled trial; Displaced geriatric femoral neck fractures; Risk factors for reoperation to promote union in 1,111 distal femur fractures; New versus old – reliability of the OTA/AO classification for trochanteric hip fractures; Risk factors for fracture-related infection after ankle fracture surgery.
The presence of facet tropism has been correlated with an elevated susceptibility to lumbar disc pathology. Our objective was to evaluate the impact of facet tropism on chronic lumbosacral discogenic pain through the analysis of clinical data and finite element modelling (FEM). Retrospective analysis was conducted on clinical data, with a specific focus on the spinal units displaying facet tropism, utilizing FEM analysis for motion simulation. We studied 318 intervertebral levels in 156 patients who had undergone provocation discography. Significant predictors of clinical findings were identified by univariate and multivariate analyses. Loading conditions were applied in FEM simulations to mimic biomechanical effects on intervertebral discs, focusing on maximal displacement and intradiscal pressures, gauged through alterations in disc morphology and physical stress.Aims
Methods
Aims. 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. Materials and Methods. 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. Results. Contact area decreased following each fracture, while anatomical
fixation restored it nearly to its intact level. Contact pressure
decreased significantly with fixation of the PMF. In plantarflexion,
the centre of force shifted significantly posteriorly in Group II
and anteriorly in Group I.
The aim of this study was to compare the functional and radiological outcomes and the complication rate after nail and plate fixation of unstable fractures of the ankle in elderly patients. In this multicentre study, 120 patients aged ≥ 60 years with an acute unstable AO/OTA type 44-B fracture of the ankle were randomized to fixation with either a nail or a plate and followed for 24 months after surgery. The primary outcome measure was the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot score. Secondary outcome measures were the Manchester-Oxford Foot Questionnaire, the Olerud and Molander Ankle score, the EuroQol five-dimension questionnaire, a visual analogue score for pain, complications, the quality of reduction of the fracture, nonunion, and the development of osteoarthritis.Aims
Methods
Metal-on-metal hip resurfacing (MoM-HR) has seen decreased usage due to safety and longevity concerns. Joint registries have highlighted the risks in females, smaller hips, and hip dysplasia. This study aimed to identify if reported risk factors are linked to revision in a long-term follow-up of MoM-HR performed by a non-designer surgeon. A retrospective review of consecutive MoM hip arthroplasties (MoM-HRAs) using Birmingham Hip Resurfacing was conducted. Data on procedure side, indication, implant sizes and orientation, highest blood cobalt and chromium ion concentrations, and all-cause revision were collected from local and UK National Joint Registry records.Aims
Methods
The risk of mechanical failure of modular revision hip stems is frequently mentioned in the literature, but little is currently known about the actual clinical failure rates of this type of prosthesis. The current retrospective long-term analysis examines the distal and modular failure patterns of the Prevision hip stem from 18 years of clinical use. A design improvement of the modular taper was introduced in 2008, and the data could also be used to compare the original and the current design of the modular connection. We performed an analysis of the Prevision modular hip stem using the manufacturer’s vigilance database and investigated different mechanical failure patterns of the hip stem from January 2004 to December 2022.Aims
Methods
We examined whether enamel matrix derivative
(EMD) could improve healing of the tendon–bone interface following
reconstruction of the anterior cruciate ligament (ACL) using a hamstring
tendon in a rat model. ACL reconstruction was performed in both
knees of 30 Sprague-Dawley rats using the flexor digitorum tendon.
The effect of commercially available EMD (EMDOGAIN), a preparation
of matrix proteins from developing porcine teeth, was evaluated.
In the left knee joint the space around the tendon–bone interface
was filled with 40 µl of EMD mixed with propylene glycol alginate
(PGA). In the right knee joint PGA alone was used. The ligament
reconstructions were evaluated histologically and biomechanically
at four, eight and 12 weeks (n = 5 at each time point). At eight weeks,
EMD had induced a significant increase in collagen fibres connecting
to bone at the tendon–bone interface (p = 0.047), whereas the control
group had few fibres and the tendon–bone interface was composed
of cellular and vascular fibrous tissues. At both eight and 12 weeks,
the mean
Different calcaneal plates with locked screws were compared in an experimental model of a calcaneal fracture. Four plate models were tested, three with uniaxially-locked screws (Synthes, Newdeal, Darco), and one with polyaxially-locked screws (90° ± 15°) (Rimbus). Synthetic calcanei were osteotomised to create a fracture model and then fixed with the plates and screws. Seven specimens for each plate model were subjected to cyclic loading (preload 20 N, 1000 cycles at 800 N, 0.75 mm/s), and
The purpose of this study was to assess the stability of a developmental pelvic reconstruction system which extends the concept of triangular osteosynthesis with fixation anterior to the lumbosacral pivot point. An unstable Tile type-C fracture, associated with a sacral transforaminal fracture, was created in synthetic pelves. The new concept was compared with three other constructs, including bilateral iliosacral screws, a tension band plate and a combined plate with screws. The pubic symphysis was plated in all cases. The pelvic ring was loaded to simulate single-stance posture in a cyclical manner until failure, defined as a displacement of 2 mm or 2°. The screws were the weakest construct, failing with a load of 50 N after 400 cycles, with maximal translation in the craniocaudal axis of 12 mm. A tension band plate resisted greater
The aim of this study was to assess the clinical and radiological outcomes of an antiprotrusio acetabular cage (APC) when used in the surgical treatment of periacetabular bone metastases. This retrospective cohort study using a prospectively collected database involved 56 patients who underwent acetabular reconstruction for periacetabular bone metastases or haematological malignancy using a single APC between January 2009 and 2020. The mean follow-up was 20 months (1 to 143). The primary outcome measure was implant survival. Postoperative radiographs were analyzed for loosening and failure. Patient and implant survival were assessed using a competing risk analysis. Secondary parameters included primary malignancy, oncological treatment, surgical factors, length of stay in hospital, and postoperative complications.Aims
Methods
Outcomes of current operative treatments for arthrofibrosis after total knee arthroplasty (TKA) are not consistently positive or predictable. Pharmacological in vivo studies have focused mostly on prevention of arthrofibrosis. This study used a rabbit model to evaluate intra-articular (IA) effects of celecoxib in treating contracted knees alone, or in combination with capsular release. A total of 24 rabbits underwent contracture-forming surgery with knee immobilization followed by remobilization surgery at eight weeks. At remobilization, one cohort underwent capsular release (n = 12), while the other cohort did not (n = 12). Both groups were divided into two subcohorts (n = 6 each) – one receiving IA injections of celecoxib, and the other receiving injections of vehicle solution (injections every day for two weeks after remobilization). Passive extension angle (PEA) was assessed in live rabbits at 10, 16, and 24 weeks, and disarticulated limbs were analyzed for capsular stiffness at 24 weeks.Aims
Methods
Aims. One of the main causes of tibial revision surgery for total knee arthroplasty is aseptic loosening. Therefore, stable fixation between the tibial component and the cement, and between the tibial component and the bone, is essential. A factor that could influence the implant stability is the implant design, with its different variations. In an existing implant system, the tibial component was modified by adding cement pockets. The aim of this experimental in vitro study was to investigate whether additional cement pockets on the underside of the tibial component could improve implant stability. The relative motion between implant and bone, the maximum pull-out force, the tibial cement mantle, and a possible path from the bone marrow to the metal-cement interface were determined. Methods. A tibial component with (group S: Attune S+) and without (group A: Attune) additional cement pockets was implanted in 15 fresh-frozen human leg pairs. The relative motion was determined under dynamic loading (extension-flexion 20° to 50°, load-level 1,200 to 2,100 N) with subsequent determination of the maximum pull-out force. In addition, the cement mantle was analyzed radiologically for possible defects, the tibia base cement adhesion, and preoperative bone mineral density (BMD). Results. The BMD showed no statistically significant difference between both groups. Group A showed for all load levels significantly higher maximum relative motion compared to group S for 20° and 50° flexion. Group S improved the maximum
Distraction osteogenesis (DO) is a useful orthopaedic procedure employed to lengthen and reshape bones by stimulating bone formation through controlled slow stretching force. Despite its promising applications, difficulties are still encountered. Our previous study demonstrated that pulsed electromagnetic field (PEMF) treatment significantly enhances bone mineralization and neovascularization, suggesting its potential application. The current study compared a new, high slew rate (HSR) PEMF signal, with different treatment durations, with the standard Food and Drug Administration (FDA)-approved signal, to determine if HSR PEMF is a better alternative for bone formation augmentation. The effects of a HSR PEMF signal with three daily treatment durations (0.5, one, and three hours/day) were investigated in an established rat DO model with comparison of an FDA-approved classic signal (three hrs/day). PEMF treatments were applied to the rats daily for 35 days, starting from the distraction phase until termination. Radiography, micro-CT (μCT), biomechanical tests, and histological examinations were employed to evaluate the quality of bone formation.Aims
Methods
Acute distal biceps tendon repair reduces fatigue-related pain and minimizes loss of supination of the forearm and strength of flexion of the elbow. We report the short- and long-term outcome following repair using fixation with a cortical button techqniue. Between October 2010 and July 2018, 102 patients with a mean age of 43 years (19 to 67), including 101 males, underwent distal biceps tendon repair less than six weeks after the injury, using cortical button fixation. The primary short-term outcome measure was the rate of complications. The primary long-term outcome measure was the abbreviated Disabilities of the Arm, Shoulder and Hand (QuickDASH) score. Secondary outcomes included the Oxford Elbow Score (OES), EuroQol five-dimension three-level score (EQ-5D-3L), satisfaction, and return to function.Aims
Methods
Using 26 cadaver shoulders, we produced a standard defect in the supraspinatus tendon and performed one of three types of repair. Their strength was found by testing in tension the force required to produce a gap of 3 mm, then 6 mm, and finally total disruption of the repair. The use of a polyethylene patch to spread the forces over the lateral bone surface and of extra sutures to grasp the tendon end raised by 2.6 times the load at which a 3 mm gap in the repair occurred and by 1.7 times the
There are concerns regarding initial stability and early periprosthetic fractures in cementless hip arthroplasty using short stems. This study aimed to investigate stress on the cortical bone around the stem and micromotions between the stem and cortical bone according to femoral stem length and positioning. In total, 12 femoral finite element models (FEMs) were constructed and tested in walking and stair-climbing. Femoral stems of three different lengths and two different positions were simulated, assuming press-fit fixation within each FEM. Stress on the cortical bone and micromotions between the stem and bone were measured in each condition.Aims
Methods
We used 15 pairs of femora from fresh human cadavers to study the effects of the size and location of the entry hole for an intramedullary nail on the strength of the femur. Right femora were used as controls. Left femora in group 1 had a 10 mm entry hole in the 'ideal' location in the piriformis fossa. Group 2 had a 14 mm entry hole in the same position and group 3 had a 14 mm entry hole anterior to this on the superior aspect of the femoral neck. Femora were equipped with strain gauges and loaded to failure in compression. There was reduced stiffness and
We aimed to determine the optimal method of inserting a screw into polymethylmethacrylate (PMMA) cement to enhance fixation. We performed six groups of ten axial pull-out tests with two sizes of screw (3.5 and 4.5 mm AO cortical) and three methods of insertion. Screws were placed into 'fluid' PMMA, into 'solid' PMMA by drilling and tapping, or into 'curing' PMMA with quarter-revolution turns every 30 seconds until the PMMA had hardened. After full hardening, we measured the maximum
Periprosthetic fractures (PPFs) around cemented taper-slip femoral prostheses often result in a femoral component that is loose at the prosthesis-cement interface, but where the cement-bone interface remains well-fixed and bone stock is good. We aim to understand how best to classify and manage these fractures by using a modification of the Vancouver classification. We reviewed 87 PPFs. Each was a first episode of fracture around a cemented femoral component, where surgical management consisted of revision surgery. Data regarding initial injury, intraoperative findings, and management were prospectively collected. Patient records and serial radiographs were reviewed to determine fracture classification, whether the bone cement was well fixed (B2W) or loose (B2L), and time to fracture union following treatment.Aims
Methods
Despite recent advances in arthroscopic rotator cuff repair, re-tear rates remain high. New methods to improve healing rates following rotator cuff repair must be sought. Our primary objective was to determine if adjunctive bone marrow stimulation with channelling five to seven days prior to arthroscopic cuff repair would lead to higher Western Ontario Rotator Cuff (WORC) scores at 24 months postoperatively compared with no channelling. A prospective, randomized controlled trial was conducted in patients undergoing arthroscopic rotator cuff repair. Patients were randomized to receive either a percutaneous bone channelling of the rotator cuff footprint or a sham procedure under ultrasound guidance five to seven days prior to index surgery. Outcome measures included the WORC, American Shoulder and Elbow Surgeons (ASES), and Constant scores, strength, ultrasound-determined healing rates, and adverse events.Aims
Methods
Comminuted and displaced fractures of the inferior pole of the patella are not easy to reduce and it is difficult to fix the fragments soundly enough to allow early movement of the knee. We have evaluated the clinical effectiveness of the separate vertical wiring technique in acute comminuted fractures of the inferior pole of the patella. A biomechanical study was also performed using ten pairs of embalmed cadaver knees. A four-part fracture was made on the inferior pole of the patella and fixed by two separate vertical wires on one side and two pull-out sutures after partial patellectomy on the other. The ultimate
To determine whether half-threaded screw holes in a new titanium locking plate design can substantially decrease the notch effects of the threads and increase the plate fatigue life. Three types (I to III) of titanium locking plates were fabricated to simulate plates used in the femur, tibia, and forearm. Two copies of each were fabricated using full- and half-threaded screw holes (called A and B, respectively). The mechanical strengths of the plates were evaluated according to the American Society for Testing and Materials (ASTM) F382-14, and the screw stability was assessed by measuring the screw removal torque and bending strength.Aims
Methods
Aims. 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. 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. Results. LP constructs demonstrated the highest mean values for initial stiffness and
To report the surgical outcome of patients with severe Scheuermann’s kyphosis treated using a consistent technique and perioperative management. We reviewed 88 consecutive patients with a severe Scheuermann's kyphosis who had undergone posterior spinal fusion with closing wedge osteotomies and hybrid instrumentation. There were 55 males and 33 females with a mean age of 15.9 years (12.0 to 24.7) at the time of surgery. We recorded their demographics, spinopelvic parameters, surgical correction, and perioperative data, and assessed the impact of surgical complications on outcome using the Scoliosis Research Society (SRS)-22 questionnaire.Aims
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
The Precice intramedullary limb-lengthening system has demonstrated significant benefits over external fixation lengthening methods, leading to a paradigm shift in limb lengthening. This study compares outcomes following antegrade and retrograde femoral lengthening in both adolescent and adult patients. A retrospective review of prospectively collected data was undertaken of a consecutive series of 107 femoral lengthening operations in 92 patients. In total, 73 antegrade nails and 34 retrograde nails were inserted. Outcome was assessed by the regenerate healing index (HI), hip and knee range of movement (ROM), and the presence of any complications.Aims
Patients and Methods
Osteolysis, secondary to local and systemic physiological effects, is a major challenge in total hip arthroplasty (THA). While osteolytic defects are commonly observed in long-term follow-up, how such lesions alter the distribution of stress is unclear. The aim of this study was to quantitatively describe the biomechanical implication of such lesions by performing subject-specific finite-element (FE) analysis on patients with osteolysis after THA. A total of 22 hemipelvis FE models were constructed in order to assess the transfer of load in 11 patients with osteolysis around the acetabular component of a THA during slow walking and a fall onto the side. There were nine men and two women. Their mean age was 69 years (55 to 81) at final follow-up. Changes in peak stress values and loads to fracture in the presence of the osteolytic defects were measured.Aims
Patients 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
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 incidence of acute Achilles tendon rupture appears to be increasing. The aim of this study was to summarize various therapies for acute Achilles tendon rupture and discuss their relative merits. A PubMed search about the management of acute Achilles tendon rupture was performed. The search was open for original manuscripts and review papers limited to publication from January 2006 to July 2017. A total of 489 papers were identified initially and finally 323 articles were suitable for this review.Objectives
Methods
Bone fracture healing is regulated by a series of complex physicochemical and biochemical processes. One of these processes is bone mineralization, which is vital for normal bone development. Phosphatase, orphan 1 (PHOSPHO1), a skeletal tissue-specific phosphatase, has been shown to be involved in the mineralization of the extracellular matrix and to maintain the structural integrity of bone. In this study, we examined how PHOSPHO1 deficiency might affect the healing and quality of fracture callus in mice. Tibial fractures were created and then stabilized in control wild-type (WT) and Objectives
Methods
Objectives. In this prospective cohort study, we investigated whether patient-specific finite element (FE) models can identify patients at risk of a pathological femoral fracture resulting from metastatic bone disease, and compared these FE predictions with clinical assessments by experienced clinicians. Methods. A total of 39 patients with non-fractured femoral metastatic lesions who were irradiated for pain were included from three radiotherapy institutes. During follow-up, nine pathological fractures occurred in seven patients. Quantitative CT-based FE models were generated for all patients. Femoral
Osteosynthesis of anterior pubic ramus fractures using one large-diameter screw can be challenging in terms of both surgical procedure and fixation stability. Small-fragment screws have the advantage of following the pelvic cortex and being more flexible. The aim of the present study was to biomechanically compare retrograde intramedullary fixation of the superior pubic ramus using either one large- or two small-diameter screws. A total of 12 human cadaveric hemipelvises were analysed in a matched pair study design. Bone mineral density of the specimens was 68 mgHA/cm3 (standard deviation (Objectives
Materials and Methods
The aim of this study was to investigate the structural integrity of torn and non-torn human acetabular labral tissue. A total of 47 human labral specimens were obtained from a biobank. These included 22 torn specimens and 25 control specimens from patients undergoing total hip arthroplasty with macroscopically normal labra. The specimens underwent dynamic shear analysis using a rheometer to measure storage modulus, as an indicator of structural integrity.Objectives
Methods
Rotator cuff tears are among the most frequent upper extremity injuries. Current treatment strategies do not address the poor quality of the muscle and tendon following chronic rotator cuff tears. Hypoxia-inducible factor-1 alpha (HIF-1α) is a transcription factor that activates many genes that are important in skeletal muscle regeneration. HIF-1α is inhibited under normal physiological conditions by the HIF prolyl 4-hydroxylases (PHDs). In this study, we used a pharmacological PHD inhibitor, GSK1120360A, to enhance the activity of HIF-1α following the repair of a chronic cuff tear, and measured muscle fibre contractility, fibrosis, gene expression, and enthesis mechanics. Chronic supraspinatus tears were induced in adult rats, and repaired 28 days later. Rats received 0 mg/kg, 3 mg/kg, or 10 mg/kg GSK1120360A daily. Collagen content, contractility, fibre type distribution and size, the expression of genes involved in fibrosis, lipid accumulation, atrophy and inflammation, and the mechanical properties of the enthesis were then assessed two weeks following surgical repair.Objectives
Methods
External fixators are the traditional fixation method of choice for contaminated open fractures. However, patient acceptance is low due to the high profile and therefore physical burden of the constructs. An externalised locking compression plate is a low profile alternative. However, the biomechanical differences have not been assessed. The objective of this study was to evaluate the axial and torsional stiffness of the externalised titanium locking compression plate (ET-LCP), the externalised stainless steel locking compression plate (ESS-LCP) and the unilateral external fixator (UEF). A fracture gap model was created to simulate comminuted mid-shaft tibia fractures using synthetic composite bones. Fifteen constructs were stabilised with ET-LCP, ESS-LCP or UEF (five constructs each). The constructs were loaded under both axial and torsional directions to determine construct stiffness.Objectives
Methods
The aim of this paper is to review the evidence relating to the
anatomy of the proximal femur, the geometry of the fracture and
the characteristics of implants and methods of fixation of intertrochanteric
fractures of the hip. Relevant papers were identified from appropriate clinical databases
and a narrative review was undertaken.Aims
Materials and Methods
We investigated the effects on fracture healing of two up-regulators of inducible nitric oxide synthase (iNOS) in a rat model of an open femoral osteotomy: tadalafil, a phosphodiesterase inhibitor, and the recently reported nutraceutical, COMB-4 (consisting of L-citrulline, Paullinia cupana, ginger and muira puama), given orally for either 14 or 42 days. Unilateral femoral osteotomies were created in 58 male rats and fixed with an intramedullary compression nail. Rats were treated daily either with vehicle, tadalafil or COMB-4. Biomechanical testing of the healed fracture was performed on day 42. The volume, mineral content and bone density of the callus were measured by quantitative CT on days 14 and 42. Expression of iNOS was measured by immunohistochemistry.Objectives
Materials and Methods
Periprosthetic femoral fractures (PFF) following total hip arthroplasty
(THA) are devastating complications that are associated with functional
limitations and increased overall mortality. Although cementless
implants have been associated with an increased risk of PFF, the
precise contribution of implant geometry and design on the risk
of both intra-operative and post-operative PFF remains poorly investigated.
A systematic review was performed to aggregate all of the PFF literature
with specific attention to the femoral implant used. A systematic search strategy of several journal databases and
recent proceedings from the American Academy of Orthopaedic Surgeons
was performed. Clinical articles were included for analysis if sufficient
implant description was provided. All articles were reviewed by
two reviewers. A review of fundamental investigations of implant
load-to-failure was performed, with the intent of identifying similar
conclusions from the clinical and fundamental literature.Aims
Patients and Methods
The fundamental concept of open reduction and internal fixation
(ORIF) of ankle fractures has not changed appreciably since the
1960s and, whilst widely used, is associated with complications
including wound dehiscence and infection, prominent hardware and
failure. Closed reduction and intramedullary fixation (CRIF) using
a fibular nail, wires or screws is biomechanically stronger, requires
minimal incisions, and has low-profile hardware. We hypothesised
that fibular nailing in the elderly would have similar functional
outcomes to standard fixation, with a reduced rate of wound and
hardware problems. A total of 100 patients (25 men, 75 women) over the age of 65
years with unstable ankle fractures were randomised to undergo standard
ORIF or fibular nailing (11 men and 39 women in the ORIF group,
14 men and 36 women in the fibular nail group). The mean age was
74 years (65 to 93) and all patients had at least one medical comorbidity. Complications,
patient related outcome measures and cost-effectiveness were assessed
over 12 months.Aims
Patients and Methods
The purpose of this study was to compare the thickness of the hip capsule in patients with surgical hip disease, either with cam-femoroacetabular impingement (FAI) or non-FAI hip pathology, with that of asymptomatic control hips. A total of 56 hips in 55 patients underwent a 3Tesla MRI of the hip. These included 40 patients with 41 hips with arthroscopically proven hip disease (16 with cam-FAI; nine men, seven women; mean age 39 years, 22 to 58) and 25 with non-FAI chondrolabral pathology (four men, 21 women; mean age 40 years, 18 to 63) as well as 15 asymptomatic volunteers, whose hips served as controls (ten men, five women; mean age 62 years, 33 to 77). The maximal capsule thickness was measured anteriorly and superiorly, and compared within and between the three groups with a gender subanalysis using student’s Objectives
Methods
To compare radiographic failure and re-operation rates of anatomical
coracoclavicular (CC) ligament reconstructional techniques with
non-anatomical techniques after chronic high grade acromioclavicular
(AC) joint injuries. We reviewed chronic AC joint reconstructions within a region-wide
healthcare system to identify surgical technique, complications,
radiographic failure and re-operations. Procedures fell into four
categories: Aims
Patients and Methods
This animal study compares different methods
of performing an osteotomy, including using an Erbium-doped Yttrium
Aluminum Garnet laser, histologically, radiologically and biomechanically.
A total of 24 New Zealand rabbits were divided into four groups
(Group I: multihole-drilling; Group II: Gigli saw; Group III: electrical
saw blade and Group IV: laser). A proximal transverse diaphyseal
osteotomy was performed on the right tibias of the rabbits after the
application of a circular external fixator. The rabbits were killed
six weeks after the procedure, the operated tibias were resected
and radiographs taken. . The specimens were tested biomechanically using three-point bending
forces, and four tibias from each group were examined histologically.
Outcome parameters were the biomechanical stability of the tibias
as assessed by the
There is an increased risk of fracture following
osteoplasty of the femoral neck for cam-type femoroacetabular impingement
(FAI). Resection of up to 30% of the anterolateral head–neck junction
has previously been considered to be safe, however, iatrogenic fractures
have been reported with resections within these limits. We re-evaluated
the amount of safe resection at the anterolateral femoral head–neck
junction using a biomechanically consistent model. In total, 28 composite bones were studied in four groups: control,
10% resection, 20% resection and 30% resection. An axial load was
applied to the adducted and flexed femur. Peak load, deflection
at time of fracture and energy to fracture were assessed using comparison
groups. There was a marked difference in the mean peak load to fracture
between the control group and the 10% resection group (p <
0.001).
The control group also tolerated significantly more deflection before
failure (p <
0.04). The mean peak load (p = 0.172), deflection
(p = 0.547), and energy to fracture (p = 0.306) did not differ significantly between
the 10%, 20%, and 30% resection groups. Any resection of the anterolateral quadrant of the femoral head–neck
junction for FAI significantly reduces the load-bearing capacity
of the proximal femur. After initial resection of cortical bone,
there is no further relevant loss of stability regardless of the
amount of trabecular bone resected. Based on our findings we recommend any patients who undergo anterolateral
femoral head–neck junction osteoplasty should be advised to modify
their post-operative routine until cortical remodelling occurs to
minimise the subsequent fracture risk. Cite this article:
The April 2014 Wrist &
Hand Roundup360 looks at: diagnosis of compressive neuropathy; relevant reviews; the biomechanics of dorsal PIP fracture dislocation; the more strands the better; and state of mind the best predictor of outcome.
The April 2014 Hip & Pelvis Roundup360 looks at: Recent arthroplasty and flight; whether that squeak could be a fracture; diagnosing early infected hip replacement; impaction grafting at a decade; whether squeaking is more common than previously thought; femoral offset associated with post THR outcomes; and periprosthetic fracture stabilisation.
There remains conflicting evidence regarding cortical bone strength
following bisphosphonate therapy. As part of a study to assess the
effects of bisphosphonate treatment on the healing of rat tibial
fractures, the mechanical properties and radiological density of
the uninjured contralateral tibia was assessed. Skeletally mature aged rats were used. A total of 14 rats received
1µg/kg ibandronate (iban) daily and 17 rats received 1 ml 0.9% sodium
chloride (control) daily. Stress at failure and toughness of the
tibial diaphysis were calculated following four-point bending tests.Objectives
Methods
We evaluated the biomechanical properties of two different methods of fixation for unstable fractures of the proximal humerus. Biomechanical testing of the two groups, locking plate alone (LP), and locking plate with a fibular strut graft (LPSG), was performed using seven pairs of human cadaveric humeri. Cyclical loads between 10 N and 80 N at 5 Hz were applied for 1 000 000 cycles. Immediately after cycling, an increasing axial load was applied at a rate of displacement of 5 mm/min. The displacement of the construct, maximum
The use of two implants to manage concomitant ipsilateral femoral
shaft and proximal femoral fractures has been indicated, but no
studies address the relationship of dynamic hip screw (DHS) side
plate screws and the intramedullary nail where failure might occur
after union. This study compares different implant configurations
in order to investigate bridging the gap between the distal DHS
and tip of the intramedullary nail. A total of 29 left synthetic femora were tested in three groups:
1) gapped short nail (GSN); 2) unicortical short nail (USN), differing
from GSN by the use of two unicortical bridging screws; and 3) bicortical
long nail (BLN), with two angled bicortical and one unicortical bridging
screws. With these findings, five matched-pairs of cadaveric femora
were tested in two groups: 1) unicortical long nail (ULN), with
a longer nail than USN and three bridging unicortical screws; and
2) BLN. Specimens were axially loaded to 22.7 kg (50 lb), and internally
rotated 90°/sec until failure.Objectives
Methods
The June 2013 Shoulder &
Elbow Roundup360 looks at: whether suture anchors are still the gold standard; infection and revision elbow arthroplasty; the variable success of elbow replacements; sliding knots; neurologic cuff pain and the suprascapular nerve; lies, damn lies and statistics; osteoarthritis; and one- or two-stage treatment for the infected shoulder revision.
Tendinopathy is a debilitating musculoskeletal
condition which can cause significant pain and lead to complete rupture
of the tendon, which often requires surgical repair. Due in part
to the large spectrum of tendon pathologies, these disorders continue
to be a clinical challenge. Animal models are often used in this
field of research as they offer an attractive framework to examine
the cascade of processes that occur throughout both tendon pathology and
repair. This review discusses the structural, mechanical, and biological
changes that occur throughout tendon pathology in animal models,
as well as strategies for the improvement of tendon healing. Cite this article:
Corticosteroids are prescribed for the treatment of many medical conditions and their adverse effects on bone, including steroid-associated osteoporosis and osteonecrosis, are well documented. Core decompression is performed to treat osteonecrosis, but the results are variable. As steroids may affect bone turnover, this study was designed to investigate bone healing within a bone tunnel after core decompression in an experimental model of steroid-associated osteonecrosis. A total of five 28-week-old New Zealand rabbits were used to establish a model of steroid-induced osteonecrosis and another five rabbits served as controls. Two weeks after the induction of osteonecrosis, core decompression was performed by creating a bone tunnel 3 mm in diameter in both distal femora of each rabbit in both the experimental osteonecrosis and control groups. An In the osteonecrosis group all measurements of bone healing and maturation were lower compared with the control group. Impaired osteogenesis and remodelling within the bone tunnel was demonstrated in the steroid-induced osteonecrosis, accompanied by inferior mechanical properties of the bone. We have confirmed impaired bone healing in a model of bone defects in rabbits with pulsed administration of corticosteroids. This finding may be important in the development of strategies for treatment to improve the prognosis of fracture healing or the repair of bone defects in patients receiving steroid treatment.
The October 2014 Trauma Roundup360 looks at: proximal humeral fractures in children; quadrilateral surface plates in transverse acetabular fractures; sleep deprivation and poor outcomes in trauma; bipolar hemiarthroplasty; skeletal traction; forefoot fractures; telemedicine in trauma; ketamine infusion for orthopaedic injuries; and improved functional outcomes seen with trauma networks.
The purpose of this study was to evaluate the
change in sagittal tibiotalar alignment after total ankle arthroplasty (TAA)
for osteoarthritis and to investigate factors affecting the restoration
of alignment. This retrospective study included 119 patients (120 ankles) who
underwent three component TAA using the Hintegra prosthesis. A total
of 63 ankles had anterior displacement of the talus before surgery
(group A), 49 had alignment in the normal range (group B), and eight
had posterior displacement of the talus (group C). Ankles in group
A were further sub-divided into those in whom normal alignment was
restored following TAA (41 ankles) and those with persistent displacement
(22 ankles). Radiographic and clinical results were assessed. Pre-operatively, the alignment in group A was significantly more
varus than that in group B, and the posterior slope of the tibial
plafond was greater (p <
0.01 in both cases). The posterior slope
of the tibial component was strongly associated with restoration
of alignment: ankles in which the alignment was restored had significantly
less posterior slope (p <
0.001). An anteriorly translated talus was restored to a normal position
after TAA in most patients. We suggest that surgeons performing
TAA using the Hintegra prosthesis should aim to insert the tibial
component at close to 90° relative to the axis of the tibia, hence
reducing posterior soft-tissue tension and allowing restoration
of normal tibiotalar alignment following surgery. Cite this article:
Small animal models of fracture repair primarily investigate
indirect fracture healing via external callus formation. We present
the first described rat model of direct fracture healing. A rat tibial osteotomy was created and fixed with compression
plating similar to that used in patients. The procedure was evaluated
in 15 cadaver rats and then Objectives
Methods
We investigated a new intramedullary locking
nail that allows the distal interlocking screws to be locked to
the nail. We compared fixation using this new implant with fixation
using either a conventional nail or a locking plate in a laboratory
simulation of an osteoporotic fracture of the distal femur. A total
of 15 human cadaver femora were used to simulate an AO 33-A3 fracture
pattern. Paired specimens compared fixation using either a locking
or non-locking retrograde nail, and using either a locking retrograde
nail or a locking plate. The constructs underwent cyclical loading
to simulate single-leg stance up to 125 000 cycles. Axial and torsional
stiffness and displacement, cycles to failure and modes of failure
were recorded for each specimen. When compared with locking plate
constructs, locking nail constructs had significantly longer mean
fatigue life (75 800 cycles ( The new locking retrograde femoral nail showed better stiffness
and fatigue life than locking plates, and superior fatigue life
to non-locking nails, which may be advantageous in elderly patients. Cite this article:
We split 100 porcine flexor tendons into five groups of 20 tendons for repair. Three groups were repaired using the Pennington modified Kessler technique, the cruciate or the Savage technique, one using one new device per tendon and the other with two new devices per tendon. Half of the tendons received supplemental circumferential Silfverskiöld type B cross-stitch. The repairs were loaded to failure and a record made of their bulk, the force required to produce a 3 mm gap, the maximum force applied before failure and the stiffness. When only one device was used repairs were equivalent to the Pennington modified Kessler for all parameters except the force to produce a 3 mm gap when supplemented with a circumferential repair, which was equivalent to the cruciate. When two devices were used the repair strength was equivalent to the cruciate repair, and when the two-device repair was supplemented with a circumferential suture the force to produce a 3 mm gap was equivalent to that of the Savage six-strand technique.
Objectives. We aimed to further evaluate the biomechanical characteristics
of two locking screws versus three standard bicortical
screws in synthetic models of normal and osteoporotic bone. Methods. Synthetic tubular bone models representing normal bone density
and osteoporotic bone density were used. Artificial fracture gaps
of 1 cm were created in each specimen before fixation with one of
two constructs: 1) two locking screws using a five-hole locking
compression plate (LCP) plate; or 2) three non-locking screws with
a seven-hole LCP plate across each side of the fracture gap. The
stiffness, maximum displacement, mode of failure and number of cycles
to failure were recorded under progressive cyclic torsional and
eccentric axial loading. Results. Locking plates in normal bone survived 10% fewer cycles to failure
during cyclic axial loading, but there was no significant difference
in maximum displacement or
We evaluated the impact of pre-coating the tibial
component with polymethylmethacrylate (PMMA) on implant survival
in a cohort of 16 548 primary NexGen total knee replacements (TKRs)
in 14 113 patients. In 13 835 TKRs a pre-coated tray was used while
in 2713 TKRs the non-pre-coated version of the same tray was used.
All the TKRs were performed between 2001 and 2009 and were cemented.
TKRs implanted with a pre-coated tibial component had a lower cumulative
survival than those with a non-pre-coated tibial component (p =
0.01). After adjusting for diagnosis, age, gender, body mass index,
American Society of Anesthesiologists grade, femoral coupling design, surgeon
volume and hospital volume, pre-coating was an independent risk
factor for all-cause aseptic revision (hazard ratio 2.75, p = 0.006).
Revision for aseptic loosening was uncommon for both pre-coated
and non-pre-coated trays (rates of 0.12% and 0%, respectively).
Pre-coating with PMMA does not appear to be protective of revision
for this tibial tray design at short-term follow-up. Cite this article:
The February 2013 Shoulder &
Elbow Roundup360 looks at: whether we should replace fractured shoulders; the limited evidence for shoulder fractures; cuffs and early physio; matrix proteins and cuff tears; long-term SLAP tear outcomes; suture anchors; recurrent Bankart repairs; and acromial morphology and calcific tendonitis.
The use of plate-and-cable constructs to treat periprosthetic fractures around a well-fixed femoral component in total hip replacements has been reported to have high rates of failure. Our aim was to evaluate the results of a surgical treatment algorithm to use these lateral constructs reliably in Vancouver type-B1 and type-C fractures. The joint was dislocated and the stability of the femoral component was meticulously evaluated in 45 type-B1 fractures. This led to the identification of nine (20%) unstable components. The fracture was considered to be suitable for single plate-and-cable fixation by a direct reduction technique if the integrity of the medial cortex could be restored. Union was achieved in 29 of 30 fractures (97%) at a mean of 6.4 months (3 to 30) in 29 type-B1 and five type-C fractures. Three patients developed an infection and one construct failed. Using this algorithm plate-and-cable constructs can be used safely, but indirect reduction with minimal soft-tissue damage could lead to shorter times to union and lower rates of complications.
This study evaluates the position of the long
head of biceps tendon using ultrasound following simple tenotomy,
in patients with arthroscopically repaired rotator cuff tears. In total, 52 patients with a mean age of 60.7 years (45 to 75)
underwent arthroscopic repair of the rotator cuff and simple tenotomy
of the long head of biceps tendon. At two years post-operatively,
ultrasound revealed that the tendon was inside the bicipital groove
in 43 patients (82.7%) and outside in nine (17.3%); in six of these
it was lying just outside the groove and in the remaining three
(5.8%) it was in a remote position with a positive Popeye Sign.
A dynamic ultrasound scan revealed that the tenotomised tendons
had adhered to the surrounding tissues (autotenodesis).The initial
condition of the tendon influenced its final position (p <
0.0005).
The presence of a Popeye sign was statistically influenced by the
pre-operative co-existence of supraspinatus and subscapularis tears (p
<
0.0001). It appears that the natural history of the tenotomised long head
of biceps tendon is to tenodese itself inside or just outside the
bicipital groove, while its pre-operative condition and coexistent
subscapularis tears play a significant role in the occurrence of
a Popeye sign.
We investigated the effect of locally administered bisphosphonate on distraction osteogenesis in a rabbit model and evaluated its systemic effect. An osteotomy on the right tibia followed by distraction for four weeks was performed on 47 immature rabbits. They were divided into seven equal groups, with each group receiving a different treatment regime. Saline and three types of dosage of alendronate (low, 0.75 μg/kg; mid, 7.5 μg/kg and high 75 μg/kg) were given by systemic injection in four groups, and saline and two dosages (low and mild) were delivered by local injection to the distraction gap in the remaining three groups. The injections were performed five times weekly during the period of distraction. After nine weeks the animals were killed and image analysis and mechanical testing were performed on the distracted right tibiae and the left tibiae which served as a control group. The local low-dose alendronate group showed a mean increase in bone mineral density of 124.3 mg/cm3 over the local saline group (analysis of variance, p <
0.05) without any adverse effect on the left control tibiae. The findings indicate that the administration of local low-dose alendronate could be an effective pharmacological means of improving bone formation in distraction osteogenesis.
Scapulothoracic fusion (STF) for painful winging
of the scapula in neuromuscular disorders can provide effective pain
relief and functional improvement, but there is little information
comparing outcomes between patients with dystrophic and non-dystrophic
conditions. We performed a retrospective review of 42 STFs in 34
patients with dystrophic and non-dystrophic conditions using a multifilament
trans-scapular, subcostal cable technique supported by a dorsal
one-third semi-tubular plate. There were 16 males and 18 females
with a mean age of 30 years (15 to 75) and a mean follow-up of 5.0
years (2.0 to 10.6). The mean Oxford shoulder score improved from
20 (4 to 39) to 31 (4 to 48). Patients with non-dystrophic conditions
had lower overall functional scores but achieved greater improvements
following STF. The mean active forward elevation increased from
59° (20° to 90°) to 97° (30° to 150°), and abduction from 51° (10°
to 90°) to 83° (30° to 130°) with a greater range of movement achieved
in the dystrophic group. Revision fusion for nonunion was undertaken
in five patients at a mean time of 17 months (7 to 31) and two required
revision for fracture. There were three pneumothoraces, two rib
fractures, three pleural effusions and six nonunions. The main risk
factors for nonunion were smoking, age and previous shoulder girdle surgery. STF is a salvage procedure that can provide good patient satisfaction
in 82% of patients with both dystrophic and non-dystrophic pathologies,
but there was a relatively high failure rate (26%) when poor outcomes
were analysed. Overall function was better in patients with dystrophic
conditions which correlated with better range of movement; however,
patients with non-dystrophic conditions achieved greater functional
improvement.
The objective of this study was to determine if a synthetic bone
substitute would provide results similar to bone from osteoporotic
femoral heads during Pushout studies were performed with the dynamic hip screw (DHS)
and the DHS Blade in both cadaveric femoral heads and artificial
bone substitutes in the form of polyurethane foam blocks of different
density. The pushout studies were performed as a means of comparing
the force displacement curves produced by each implant within each
material.Introduction
Methods
Peri-tendinous injection of local anaesthetic,
both alone and in combination with corticosteroids, is commonly performed
in the treatment of tendinopathies. Previous studies have shown
that local anaesthetics and corticosteroids are chondrotoxic, but
their effect on tenocytes remains unknown. We compared the effects
of lidocaine and ropivacaine, alone or combined with dexamethasone,
on the viability of cultured bovine tenocytes. Tenocytes were exposed
to ten different conditions: 1) normal saline; 2) 1% lidocaine;
3) 2% lidocaine; 4) 0.2% ropivacaine; 5) 0.5% ropivacaine; 6) dexamethasone
(dex); 7) 1% lidocaine+dex; 8) 2% lidocaine+dex; 9) 0.2% ropivacaine+dex;
and 10) 0.5% ropivacaine+dex, for 30 minutes. After a 24-hour recovery
period, the viability of the tenocytes was quantified using the
CellTiter-Glo viability assay and fluorescence-activated cell sorting
(FACS) for live/dead cell counts. A 30-minute exposure to lidocaine
alone was significantly toxic to the tenocytes in a dose-dependent
manner, but a 30-minute exposure to ropivacaine or dexamethasone
alone was not significantly toxic. Dexamethasone potentiated ropivacaine tenocyte toxicity at higher
doses of ropivacaine, but did not potentiate lidocaine tenocyte
toxicity. As seen in other cell types, lidocaine has a dose-dependent
toxicity to tenocytes but ropivacaine is not significantly toxic.
Although dexamethasone alone is not toxic, its combination with
0.5% ropivacaine significantly increased its toxicity to tenocytes.
These findings might be relevant to clinical practice and warrant
further investigation.
Filling the empty holes in peri-articular locking
plates may improve the fatigue strength of the fixation. The purpose of
this A locking/compression plate was applied to 33 synthetic femurs
and then a 6 cm metaphyseal defect was created (AO Type 33-A3).
The specimens were then divided into three groups: unplugged, plugged
with locking screw only and fully plugged holes. They were then
tested using a stepwise or run-out fatigue protocol, each applying
cyclic physiological multiaxial loads. All specimens in the stepwise group failed at the 770 N load
level. The mean number of cycles to failure for the stepwise specimen
was 25 500 cycles ( In conclusion, filling the empty combination locking/compression
holes in peri-articular distal femur locking plates at the level
of supracondylar comminution does not increase the fatigue life
of the fixation in a comminuted supracondylar femoral fracture model
(AO 33-A3) with a 6 cm gap.
The goals of this study were: 1) to determine if high-fat diet
(HFD) feeding in female mice would negatively impact biomechanical
and histologic consequences on the Achilles tendon and quadriceps
muscle; and 2) to investigate whether exercise and branched-chain
amino acid (BCAA) supplementation would affect these parameters
or attenuate any negative consequences resulting from HFD consumption. We examined the effects of 16 weeks of 60% HFD feeding, voluntary
exercise (free choice wheel running) and BCAA administration in
female C57BL/6 mice. The Achilles tendons and quadriceps muscles
were removed at the end of the experiment and assessed histologically
and biomechanically.Objectives
Methods