The benefit of using acetabular screws in primary total hip arthroplasty (THA) has been questioned in recent years. The disadvantages of using screws include increased operative time, risk of injury to surrounding neurovascular structures and metal ware breakage. Recent large registry studies have reported that screws do not confer a protective effect against acetabular loosening or the presence of osteolysis. Other studies have even described an increased risk of aseptic acetabular loosening with the selective use of screws. We report findings from a multicentre cohort study. This large cohort study compared clinical outcomes between primary acetabular components that were inserted with and without screws. Independent variables included the presence (or absence) of screws, the total number of screws used and the cumulative screw length (CSL). Outcome measures included all-cause revision, acetabular component revision and acetabular component loosening. Statistical software (Stata/IC 13.1 for Mac [64-bit Intel]) was used to conduct all statistical analyses. A p-value < 0 .05 taken to be significant. There were 4,583 THAs performed in total.
A retrospective review of 51 consecutive patients undergoing fixation of Scaphoid fractures by two surgeons in a single institution was conducted. Twenty-four patients were treated with a Herbert screw and twenty-seven with an Acutrak screw. This included six patients who underwent acute fixation, three in each group. The remaining cases were for the treatment of non-union and delayed union. There were no significant differences between the two groups in terms of age, side of injury, and mechanism of injury. Fractures were classified as proximal, middle and distal thirds of the Scaphoid and there was no significant difference between the groups regarding the types of fractures treated. The only significant difference between the groups was the time from injury to fixation when considering the cases of delayed union and non union which was greater in the Herbert screw group (7.5 months vs 4 months p=<0.05). There was no significant difference in outcome between the two methods of fixation. Union rates for all cases were 79% for Herbert screws and 81% for Acutrak screws and 82% and 83% respectively when only considering the delayed union/non-union procedures. There was no difference in terms of time to union, further surgery or clinical outcome between the two groups. The Acutrak screw required removal in five patients and the Herbert screw in two due to symptoms from screw prominence. This was not statistically significant. In conclusion there is no significant difference in surgical outcome between these two methods of fixation for Scaphoid fractures. The authors feel that this supports the view that biological factors are more important than the method of fixation in obtaining union of Scaphoid fractures.
Distal interphalangeal joint (DIPJ) fusion using a k-wire has been the gold standard treatment for DIPJ arthritis. Recent studies have shown similar patient outcomes with the headless compression screws (HCS), however there has been no cost analysis to compare the two. Therefore, this study aims to 1) review the cost of DIPJ fusion between k-wire and HCS 2) compare functional outcome and patient satisfaction between the two groups. A retrospective review was performed over a nine-year period from 2012-2021 in Counties Manukau. Cost analysis was performed between patients who underwent DIPJ fusion with either HCS or k-wire. Costs included were surgical cost, repeat operations and follow-up clinic costs. The difference in pre-operative and post-operative functional and pain scores were also compared using the patient rate wrist/hand evaluation (PRWHE). Of the 85 eligible patients, 49 underwent fusion with k-wires and 36 had HCS. The overall cost was significantly lower in the HCS group which was 6554 New Zealand Dollars (NZD), whereas this was 10408 NZD in the k-wire group (p<0.0001). The adjusted relative risk of 1.3 indicate that the cost of k-wires is 1.3 times more than HCS (P=0.0053). The patients’ post-operative PRWHE pain (−22 vs −18, p<0.0001) and functional scores (−38 vs −36, p<0.0001) improved significantly in HCS group compared to the k-wire group. Literatures have shown similar DIPJ fusion outcomes between k-wire and HCS. K-wires often need to be removed post-operatively due to the metalware irritation. This leads to more surgical procedures and clinic follow-ups, which overall increases the cost of DIPJ fusion with k-wires. DIPJ fusion with HCS is a more cost-effective with a lower surgical and follow-up costs compared to the k-wiring technique. Patients with HCS also tend to have a significant improvement in post-operative pain and functional scores.
Non-union is debilitating, costly and affects 2–8% of intramedullary fixed fractures. Clinical data suggest that percutaneous interfragmentary screws offer a less invasive alternative to exchange nailing. This study aimed to assess their efficiency with biomechanical analyses. A tibia was prepared for finite element analysis by creating a fracture of AO classification 42A2b, prior to reaming and insertion of an intramedullary nail. A callus was modelled as granulation tissue and gait loads were applied. The model was validated against published data and with sensitivity studies. The effects of weightbearing, fracture gap and angle, percutaneous screws and exchange nailing were compared through quantification of interfragmentary motion and strain, with the latter used to gauge healing performance via mechano-regulation theory.Introduction
Materials and Methods
Non-unions often arise because of high strain environments at fracture sites. Revision fixation, bone grafting and biologic treatments to treat long bone fracture non-union can be expensive and invasive. Percutaneous strain reduction screws (PSRS) can be inserted as a day-case surgical procedure to supplement primary fixation at a fraction of the cost of traditional treatments. Screw insertion perpendicular to the plane of a non-union can resist shear forces and achieve union by modifying the strain environment. A multi-centre retrospective study was undertaken to confirm the results of the initial published case series, ascertain whether this technique can be adopted outside of the developing institution and assess the financial impact of this technique. Retrospective analysis was performed for all PSRS cases used to treat un-united long bone fractures in four level 1 trauma centres from 2016 to 2020. All patients were followed up until union was achieved or further management was required. Demographic data was collected on patients, as were data about their injuries, initial management and timings of all treatments received. A comparative cost analysis was performed comparing patients treated with PSRS and with traditional non-union surgery methods.Introduction
Materials and Methods
Loosening of the baseplate is one of the most common causes of failure in Reverse Shoulder Arthroplasty. To allow osteo-integration to occur and thus provide long-term stability, initial screws fixation plays a pivotal role. In particular, tightening torque and force of nonlocking screws are two parameters that are considered to have a clear impact on implant stability, yet the relation is not fully understood. For this reason, this study aims to define an experimental set-up, to measure force and torque in artificial bone samples of different quality, in order to estimate ranges of optimal surgical values and give guidelines to maximize screw fixation and therefore initial implant stability. A custom-made torque sensor (Figure 1a) was built and calibrated using a lever deadweight system. To measure the compression force generated by the screw head, three thin FlexiForce sensors (Tekscan, South Boston, US) were enclosed between two 3D printed plates with a central hole to allow screw insertion (Figure 1b). The tightening force, represented by the sum of the three sensors, was calibrated using a uniaxial testing machine (Zwick/Roell, Ulm, Germany). Multiple screw lengths (26mm, 32mm and 47mm) were selected in the protocol. Synthetic bone blocks (Sawbones; Malmö, Sweden) of 20 and 30 PCF were used to account for bone quality variation. To evaluate the effect of a cortical bone layer, for each density three blocks were considered with 0 mm (no layer), 1.5 mm and 3 mm of laminate foam of 50 PCF. The holes for the screws were pre-drilled in the same way as in the operation room. For each combination of screw dimensions and bone quality, ten measurements were performed by acquiring the signal of the insertion torque and tightening force until bone breaking.Introduction
Methods
Longstanding un-united scaphoid fractures or scapholunate insufficiency can progress to degenerative wrist osteoarthritis (termed scaphoid non-union advanced collapse (SNAC) or scapho-lunate advanced collapse (SLAC) respectively). Scaphoid excision and partial wrist fusion is a well-established procedure for the surgical treatment of this condition. In this study we present a novel technique and mid-term results, where fusion is reserved for the luno-capitate and triquetro-hamate joints, commonly referred to as bicolumnar fusion. The purpose of this study was to report functional and radiological outcomes in a series of patients who underwent this surgical technique. This was a prospective study of 23 consecutive patients (25 wrists) who underwent a bicolumnar carpal fusion from January 2014 to January 2017 due to a stage 2 or 3 SNAC/SLAC wrist, with a minimum follow-up of one year. In all cases two retrograde cannulated headless compression screws were used for inter-carpal fixation. The clinical assessment consisted of range of motion, grip and pinch strength that were compared with the unaffected contralateral side where possible. Patient-reported outcome measures, including the DASH and PRWE scores were analysed. The radiographic assessment parameters consisted of fusion state and the appearance of the radio-lunate joint space. We also examined the relationship between the capito-lunate fusion angle and wrist range of motion, comparing wrists fused with a capito-lunate angle greater than 20° of extension with wrists fused in a neutral position. The average follow-up was 2.9 years. The mean wrist extension was 41°, flexion 36° and radial-ulnar deviation arc was 43° (70%, 52% and 63% of contralateral side respectively). Grip strength was 40 kg and pinch strength was 8.9 kg, both 93% of contralateral side. Residual pain for activities of daily living was 1.4 (VAS). The mean DASH and PRWE scores were 19±16 and 29±18 respectively. There were three cases of non-union (fusion rate of 88%). Two wrists were converted to total wrist arthroplasty and one partial fusion was revised and healed successfully. Patients with an extended capito-lunate fusion angle trended toward more wrist extension but this did not reach statistical significance (P= 0.07). Wrist flexion did not differ between groups. Radio-lunate joint space narrowing progressed in 2 patients but did not affect their functional outcome. After bicolumnar carpal fusion using retrograde headless screws, patients in this series maintained a functional flexion-extension arc of motion, with grip-pinch strength that was close to normal. These functional outcomes and fusion rates were comparable with standard 4-corner fusion technique. A capito-lunate fusion angle greater than 20° may provide more wrist extension but further investigation is required to establish this effect. This technique has the advantage that compression screws are placed in a retrograde fashion, which does not violate the proximal articular surface of the lunate, preserving the residual load-bearing articulation. Moreover, the hardware is completely contained, with no revision surgery for hardware removal required in this series.
Surgeons fixing scaphoid fractures need to be familiar with its morphological variations and their implications on safe screw placement during fixation of these fractures. Literature has limited data in this regard. The purpose of this CT-based study was to investigate scaphoid morphometry and to analyse the safe trajectories of screw placement in scaphoid. We measured the coronal and Sagittal widths of scaphoid in CT-scans of 60 patients using CT based data from 50 live subjects with intact scaphoid. Safe placements for screws with diameters of 1.7mm, 2.4mm, 3.5mm and 4mm were studied using trajectories with additional 2mm safety corridor.Introduction
Methods
Peri-prosthetic humerus fractures are relatively uncommon occurrences that can be difficult to manage non-operatively. Locking plate technology has enhanced the surgical management of these fractures. We describe an osteosynthesis technique utilizing a locking plate with eccentrically placed screw holes to place “skive screws” in the proximal end of the plate to achieve fixation around the stem of the implant. A retrospective review of prospectively collected data was performed for a consecutive series of patients treated with this skive screw technique from May 2011 to September 2014. Seven patients presented with postoperative type B peri-prosthetic humerus fractures. Average follow-up was 24 months. Radiographic analysis was performed on most recent postoperative imaging. Clinical outcomes were assessed using VAS pain, ASES total score, ASES functional score, SST, SANE, range of motion and strength.Background
Methods
Isolated injuries of the sacral bone are rare. The pathomechanism of these injuries are usually high velocity accidents or falls from large heights. The computer-assisted implantation of iliosacral screws (SI-screw) becomes more important in the treatment of dorsal pelvic ring fractures. The advantage of the minimal-invasive screw placement is the reduction of the non-union and deep wound infection rate. Another advantage of computer-navigated SI-screw placement is the reduction of intraoperative radiation for the patient and the surgical staff. The purpose of this study was to analyse the position of navigated iliosacral screws. In the study group 74 screws (49 patients) were included and radiologically analysed. All screws were implanted using 3D-navigation (BrainLAB Vector Vision, Brainlab, Germany). Navigation was always executed with the same 3D c-arm (ARCADIS Orbic 3D, Siemens, Germany) and navigation system. We determined the grade of perforation and angular deviation in the postoperative CT-scans in all screws. The classification was performed according to Smith et al in 4 grades. Grade 0 implies no perforation and grade 1 a perforation less than 2 mm. Grade 2 correlates a perforation of 2–4 mm and grade 3 a perforation of more than 4 mm. Furthermore the intra- and postoperative complications as well as the body-mass-index, the co-morbidities and the duration of radiation were documented. The statistical analysis was executed using Microsoft Excel 2003.INTRODUCTION
METHODS
Cases of intertrochanteric hip fractures as a result of osteoporosis have been increasing in recent years. Treatment of these types of fractures is often performed with intramedullary (IM) nails or compression hip screws (CHS) [1]. IM nails are composed of a stem, which is inserted into the medullary canal of the femur, and a lag screw that is placed inside the head of the femur. One problem with this type of device is that both the left and right femurs are fixed with IM nails that have right-hand threaded lag screws. Therefore, on left femurs, the right-handed threads may not provide satisfactory fixation in the bone. This insufficient fixation could cause rotary motion and slippage in the femoral head, which would inhibit fracture healing. This study used three-dimensional finite element analysis (FEA) to examine the fixation and rotational characteristics in reference to the thread direction of the lag screw and the relative angle between the stem and lag screw. In this study, a 3D CAD model of a left femur and four proximal femoral IM nail designs were analyzed in FEA for stress and displacement. An intertrochanteric femoral fracture was created so that the femoral head and diaphysis were separated. The four IM nails were designed to with either left or right-handed lag screw threads (figure .1) and with relative stem-lag screw angles of 125 or 135 degrees. (Traditional IM nails use a right-handed screw and a relative angle of 125 degrees.) The results showed the femoral head displacement was smaller when using the left-handed lag screw. It is thought that this difference between the left and right-handed screws is caused by the direction of rotation, which would cause the left-handed screw to tighten and the right-handed screw to loosen within the femoral head. The femoral head displacement also decreased with a screw-stem angle of 135 degrees in comparison to the standard 125 degree angle. The standard right-handed screw with 125 degree relative angle was shown to have the largest displacement of all four types of tested IM nails, whereas the left-handed, 135 relative degree design produced the smallest displacement of all four implants. These results show how using a left-handed lag screw with proper relative angles in the left femur, effectively reduces femoral head displacement when compared to traditional right-handed lag screw IM implants. This is important for the promotion of intertrochanteric fracture healing.
The bone defect reconstruction is the first step of successful primary or revision TKA in case of large bone defect. If the defect is not reconstructed adequately, we can neither preserve knee joint function nor guarantee long survival of the implant. Allogeneic bone graft is known to be the treatment of choice in large defect. However the surgical technique is demanding and incorporation failure is constant issue of the allogeneic bone graft. We propose new bone defect reconstruction technique using multiple screws and cement. From April 2012 to April 2014, 12 patients with large defect which could not be reconstructed with metal augment were involved in this study. The bone defect type was 10 cases of 2A and 2 cases of 2B according to AORI (Anderson Orthopedic Research Institute) classification. The defect was reconstructed with multiple screws and cementing technique by single surgeon (WS Cho). Average follow-up period was 15 months. (24 ∼ 1 month)Introduction
Material and method
Cannulated screw is commonly used in the fixation of proximal femoral neck fractures. In the literature, several configurations had been proposed for best mechanical support with clinical experiences or biomechanical tests. Although screws in triangle configuration contribute certain fixation stability, but sometimes the surgeons made their own choices have to conduct another fixation pattern for some factors such as fracture type, economic issues, and so on. Therefore the aim of this study is to analyze the mechanical responses of a fractured femur fixed with screws in different configurations, screw materials and screw diameters with finite element method, trying to find the most stable construct. A solid femur model was built from the CT images of a standard saw bone. Three fracture types of the femoral neck were created according to Pauwel's classification (30?, 50?, 70?) by CAD software. The models of implanted screws were built according to a commercial cannulated screw (Stryker Osteosynthesis, Schoenkirchen/Kiel, Germany) with diameter 6.5mm and 4.5mm by CAD software, too. Three fixation configurations were analyzed in this study, including triangle with superior single screw with titanium diameter 6.5mm, triangle with inferior single screw with diameter 6.5mm and diamond with four stainless screw diameter 4.5mm (fig.1). Totally there were nine models constructed in this study, and all of them were then imported into ANSYS WORKBENCH v14 (Swanson Analysis, Houston, PA, USA) to mesh and further analysis. 700N vertical downward force was applied on the femur head and the distal end of femur shaft was totally fixed. The triangle fixation with superior single screw resulted in a best stability, but the fracture fixed with screws in a diamond configuration has least fracture gap. The difference of the maximum displacement of the femur head with Pauwel's classification 70?between triangle fixation with superior single screw and diamond configuration is only 0.03mm (1.72–1.69 mm). In most unstable femoral neck fracture [Pauwel's classification 70], the maximum gap distance is 0.59mm under the diamond configuration, while it is 0.63mm as the fracture fixed with a triangle configuration. Therefore, this study suggests that four 4.5mm stainless screws in a diamond configuration is an alternative for proximal femur fracture once 6.5mm titanium screws are not available.
Osteoporotic intertrochanteric fracture (ITF) is frequent injuries affecting elderly, osteoporotic patients leading to significant morbidity and mortality. Successful prognosis including union and alignment is challenging even though initial successful reduction with internal fixation. Although many factors are related to the patient's final prognosis. Well reduction with stable fracture fixation is still the goal of treatment to improve the quality of life and decrease morbidity in patients with hip fractures, but this in turn depends on the type of fracture and bone quality. Poor bone quality is responsible for common complications, such as failure of fixation, varus collapse and lag screw cut-out, in elderly patients. Kim et al. found that the complication rate when using conventional DHS in unstable ITFs can be as high as 50% because of screw cut-out. We used the dynamic hip screws (DHS) strengthened by calcium phosphate cement (CPC) for treatment femoral intertrochanteric fracture and review the prognosis of our patients. From January of 2011 to January of 2014, 42 patients with femoral intertrochanteric fracture underwent surgery with DHS strengthened by CPC. Comparisons were made between the DHS plus CPC group with the other patients with only DHS used in our department. All patients were followed up for an average time of 14.8(6 to 24) months. X-ray was reviewed for the conditions of union and implant failure.Introduction
Materials and Methods
Revision Total Hip Arthroplasty can be challenging in case of thin or fragile femur. Primary Bipolar Hip Prosthesis (BHP) is also difficult in severe osteoporosis case. We have used titanium alloy cementless stem with interlocking screws for revision THA since 2003, and primary BHP in senile case since 2007. Thirty four cementless THA were performed with interlocking stem (27 S-LOCK and 7 Delta-LOCK) since 2007, and 26 cases were followed for more than one year. Two for primary THA and 24 for revision THA, 3 were male and 23 were female. Seven primary Bipolar Hip Prosthesis with interlocking screw stem for femoral neck fracture were also followed more than one year. All seven BHP cases were female. Stress shielding in X-ray film were observed in 3 revision THA cases during follow up, but no pain were complained. No breakage of screws and stems were observed, and no infections and no fractures were occurred. In case of loosened stem, long interlocking stem can bypass the weak point of femur after removal of cement or metal stem tip. Patients can walk immediately after revision THA or primary BHP. Cementless interlocking stem in THA and BHP is useful for management of thin or fragile femoral cortex.
It is well established that non-union of the scaphoid requires operative intervention to achieve stable union, restore scaphoid anatomy and prevent further degenerative change. Acutrak screw has been shown to have better biomechanical compression properties than the Herbert screw in the laboratory setting. The aims of the study were to assess the rate of union, the functional outcome and post- operative complications of patients with the two different screw systems. A retrospective review of the patients who had undergone surgery for non-union of scaphoid treated by a single surgeon. The first group consisted of 61 patients who were treated with Herbert screw and iliac crest bone graft between July 1996 and June 2000. The rate and time to union were assessed clinically and radiologicaly. Their post-operative functional outcome was assessed with modified Mayo wrist score. Results were compared to second group of 71 patients treated with Acutrak screw plus iliac crest bone graft between July 2000 and December 2005.Introduction
Methods
Fixation of the distal fibula in conjunction with ankle fractures has not changed over the last 50 years. The complication rate of these fixation techniques is as high as 30%. The fibula nail is an alternative method of fixation and uses a minimal invasive technique. This technique preserves soft tissue compared to previous techniques used, and fewer soft tissue complications. We reviewed the preliminary results of 178 patients with unstable Weber B and C ankle fractures that were operated on in our unit between January 2012 and February 2013. We used the Acumed fibular nail for reduction and fixation of the lateral malleolus. Using the nail we had significant reduction in our operating time. Patients were discharged one day post operation without any POP and partial weight bearing on crutches. Various parameters were measured on all the follow- up x-rays and assessed for incongruencies compared with the normal ankle. These parameters were medial clearspace, talo-crural angle, talar tilt and fibular length. No patients thus far have had any loss of fixation. The Olerud and Molander score was used at three month and six month follow up.Introduction
Method
Pedicle screw fixation commonly uses a manual probe technique for preparation and insertion of the screw. However, the accuracy of obtaining a centrally located path using the probe is often dependent on the experience of the surgeon and may lead to increased complications. Fluoroscopy and navigation assistance improves accuracy but may expose the patient and surgeon to excessive radiation. DSG measures electrical conductivity at the tip and provides the surgeon with real-time audio and visual feedback based on differences in tissue density between cortical and cancellous bone and soft tissue. The authors investigated the effectiveness of DSG for training residents on safe placement of pedicle screws. 15 male cadaveric thoracolumbar spine specimens were fresh-frozen at the time of expiration. Residents were assigned 3 specimens each and randomised by pedicle side and order of technique for pedicle screw placement (free-hand versus DSG). Fluoroscopy and other navigation assistance were not used for pedicle preparation. All specimens were imaged using CT following insertion of all pedicle screws. The accuracy was assessed by a senior radiologist and graded as within (≤ 2mm breach) or outside (> 2mm breach) the pedicle.Introduction
Methods
Composite screws of uncalcined and unsintered hydroxyapatite (HA) particles and poly-l-lactide (PLLA) were developed as completely absorbable bone fixation devices. So far the durability of HA-PLLA composite screws is unclear when used for the fixation of acetabular bone graft in total hip arthroplasty under full-weight conditions. We have used this type of screw for the fixation of acetabular bone graft in cemented or reverse-hybrid total hip arthroplasty since 2003. Hence, we conducted a follow-up study to assess the safety and efficacy of these screws when used for cemented socket fixation. During 2003–2009, HA-PLLA composite screws were used for fixation of acetabular bone graft in cemented or reverse-hybrid primary THA in 106 patients (114 cases). All the THAs were performed through direct lateral approaches, and postoperative gait exercise with full weight bearing usually started two days after surgery. One patient died of an unrelated disease and seven patients were lost to follow-up within 5 years. Finally, 98 patients (106 cases) were followed up for over 5 years and were reviewed retrospectively (follow-up rate, 93%). Radiographic loosening of the acetabular component was assessed according to the criteria of Hodgkinson et al., and the radiolucent line around the socket was evaluated in all zones, as described by DeLee and Charnley.Background
Methods
To compare the ability of a new composite bio-absorbable screw and two conventional metal screws to maintain fixation of scaphoid waist-fractures under dynamic loading conditions. Fifteen porcine radial carpi, with morphology comparable to human scaphoids, were osteotomised at the waist. Specimens were randomised in three groups: Group I were fixed with a headed metal screw, group II with a headless tapered metal screw and group III with a bio-absorbable composite screw. Each specimen was oriented at 45° and cyclically loaded using four blocks of 1000 cycles, with peak loads of 40, 60 (normal load), 80 and 100 N (severe load) respectively. Permanent displacement and translation (step-off) at the fracture site was measured after each loading block from a standardised high-magnification photograph using image analysis software (Roman v1.70, Institute of Orthopaedics, Oswestry). Statistical analysis was by ANOVA and tolerance limits.Objective
Methods
