Revision total knee arthroplasty (rTKA) is a high stakes procedure with complex equipment and multiple steps. For rTKA using the ATTUNE system revising femoral and tibial components with sleeves and stems, there are over 240 pieces of equipment that require correct assembly at the appropriate time. Due to changing teams, work rotas, and the infrequency of rTKR, scrub nurses may encounter these operations infrequently and often rely heavily on company representatives to guide them. In turn, this delays and interrupts surgical efficiency and can result in error. This study investigates the impact of a fully immersive virtual reality (VR) curriculum on training scrub nurses in technical skills and knowledge of performing a complex rTKA, to improve efficiency and reduce error. Ten orthopaedic scrub nurses were recruited and trained in four VR sessions over a 4-week period. Each VR session involved a guided mode, where participants were taught the steps of rTKA surgery by the simulator in a simulated operating theatre. The latter 3 sessions involved a guided mode followed by an unguided VR assessment. Outcome measures in the unguided assessment were related to procedural sequence, duration of surgery and efficiency of movement. Transfer of skills was assessed during a pre-training and post-training assessment, where participants completed multi-step instrument selection and assembly using the real equipment. A pre and post-training questionnaire assessed the participants knowledge, confidence and anxiety.Background
Method
Three anatomic landmarks are typically used to estimate proper femoral component rotation in total knee arthroplasty: the transepicondylar axis (TEA), Whiteside's line, and the posterior condylar axis (PCA). Previous studies have shown that the presence of tibia vara may be accompanied by a hyperplastic posteromedial femoral condyle, which affects the relationship between the PCA and the TEA. The purpose of this study was to determine the relationship of tibia vara with the PCA. Two hundred and forty-eight knees underwent planning for total knee arthroplasty with MRI. The MRI was used to characterize the relationship between the transepicondylar axis and the posterior condylar axis. Long-leg standing films (LLSF) were obtained to evaluate the medial proximal tibial angle. The MPTA is defined as the medial angle formed between a line along the anatomic axis of the tibia and a line along the tibial plateau.Introduction
Methods
While implant designs and surgical techniques have improved in total knee arthroplasty (TKA), approximately 20% of patients remain dissatisfied. The purpose of this study was to determine if reproduction of anatomic preoperative measurements correlated to improved clinical outcomes in TKA. We retrospectively reviewed95 patients (106 knees) who underwent a TKA between 2012 −2013 with a minimum of one year follow-up. All patients had a pre and post-operative SF-12 and WOMAC scores. Pre and 6 week post-operative radiographs were reviewed to compare restoration of coronal plane alignment, maintenance of joint line obliquity, and maintenance of tibial varus. Coronal alignment was defined as the angle formed between the mechanical axis of the femur and the the tibia. Joint line obliquity was defined as the angle between the mechanical axis of the limb and the line which best parallels the joint space at the knee. Tibial varus was compared between the preoperative proximal lateral tibial angle and the angle formed by the mechanical axis of the tibia and tibial component postoperatively.Introduction
Methods
Current techniques in total knee arthroplasty aim to restore the coronal mechanical axis to neutral. Preoperative planning has historically been based on long-leg standing films (LLSF) which allow surgeons to plan bony resection and soft tissue releases. However, LSSF can be prone to error if malrotated. Recently, patient-specific guides (PSG) utilizing supine magnetic resonance imaging (sMRI) have become an accepted technique for preoperative planning. In this study we sought to compare the degree of coronal deformity using LLSF and sMRI. Two hundred thirty knees underwent planning for total knee arthroplasty with sMRI and LLSF. Coronal plane deformity was determined based on the femoral-tibial angle (FTA) as defined by the angle formed between a line from the center of the femoral head to the intercondylar notch and a line from the middle of the tibial spines to the middle of the ankle joint. Mechanical axis values from the sMRI were compared with values obtained from LLSFIntroduction
Methods
Total knee arthroplasty is effective for the management of osteoarthritis of the knee. Conventional techniques utilizing manual instrumentation (MI) make use of intramedullary femoral guides and either extramedullary or intramedullary tibial guides. While MI techniques can achieve excellent results in the majority of patients, those with ipsilateral hardware, post-traumatic deformity or abnormal anatomy may be technically more challenging, resulting in poorer outcomes. Computer-assisted navigation (CAN) is an alternative that utilizes fixed trackers and anatomic registration points, foregoing the need for intramedullary guides. This technique has been shown to yield excellent results including superior alignment outcomes compared to MI with fewer outliers. However, studies report a high learning curve, increased expenses and increased operative times. As a result, few surgeons are trained and comfortable utilizing CAN. Patient-specific instrumentation is an alternative innovation for total knee arthroplasty. Custom guide blocks are fabricated based on a patient's unique anatomy, allowing for the benefits of CAN but without the increased operative times or the high learning curve. In this study we sought to evaluate the accuracy of PSI techniques in patients with previous ipsilateral hardware of the femur. After reviewing our database of 300 PSI total knee arthroplasty patients, 16 were identified (10 male, 6 female) using the Zimmer NexGen Patient Specific Instrumentation System. Fourteen patients included in the study had a preexisting total hip arthroplasty on the ipsilateral side [Figure 1], 1 had a sliding hip screw, and 1 patient had a cephalomedullary nail. Postoperative mechanical axis alignment measurements were performed using plain long-standing radiographs [Figure 2]. The American Knee Society Score was used to evaluate clinical outcomes postoperatively.Introduction
Methods
Total knee arthroplasty (TKA) is an effective operation for the management of osteoarthritis of the knee. Conventional technique utilizing manual instrumentation (MI) allows for reproducible and accurate execution of the procedure. The most common techniques make use of intramedullary femoral guides and either extrameduallary or intrameduallary tibial guides. While these methods can achieve excellent results in the majority of patients, those with ipsilateral hardware, post-traumatic deformity or abnormal anatomy may preclude the accurate use of these techniques. Patient-specific instrumentation (PSI) is an alternative innovation for total knee arthroplasty. Utilizing magnetic resonance imaging (MRI) or computed tomography (CT), custom guide blocks are fabricated based on a patient's unique anatomy. This allows for the benefits of computer assisted navigation (CAN) but without the increased operative times or the high learning curve associated with it. Furthermore it allows the use of familiar cutting blocks and guides to check the accuracy of the PSI guide blocks. In this study we sought to evaluate the accuracy of PSI techniques in patients with previous ipsilateral hardware, which would make the use of MI technically challenging and possibly subject to inaccuracy. After reviewing our database of 300 PSI total knee arthroplasty patients, 16 patients were identified (10 male, 6 female) using the Zimmer NexGen Patient Specific Instrumentation System. Fourteen patients included in the study had a preexisting total hip arthroplasty on the ipsilateral side, 1 had a preexisting sliding hip screw, and 1 patient had a preexisting cephalomedullary nail. Postoperative mechanical axis alignment measurements were performed using plain long-standing radiographs. The American Knee Society Score was used to evaluate clinical outcomes postoperatively.Introduction:
Methods:
Patient specific instrumentation (PSI) is an innovative technology in total knee arthroplasty. With the use of a preoperative MRI or CT scan, custom guide blocks are individually manufactured for each patient. Contrary to other TKA technologies such as computer-assisted surgery, PSI utilizes measured resection technique rather than a primarily ligament balancing technique. This has the potential to negatively affect the operating surgeon's ability to achieve optimal soft tissue balancing, which is especially critical in patients with severe lower extremity malalignment. Despite early research suggesting that PSI is accurate, has a low learning curve, and can reduce OR time, it remains unclear whether a surgeon using PSI can achieve optimal soft tissue balancing using a measured resection technique. The purpose of this study is to evaluate the efficacy of PSI in patients with severe preoperative limb alignment deformities. Fifty PSI total knee arthroplasties were performed on 46 patients (21 male, 25 female) using the Zimmer NexGen Patient Specific Instrumentation system. Each patient included in the study had a minimum preoperative deformity of at least 10° varus or valgus measured on preoperative long leg standing radiographs, Zimmer preoperative software or both. Forty-three of the included knees had a varus deformity and 7 had a valgus deformity. Preoperative mechanical axis alignment measurements were obtained using the PSI preoperative planning software and were manually calculated using pre-operative long leg standing radiographs. Postoperative mechanical axis alignment measurements were calculated using plain long leg standing radiographs. The Knee Society Scoring System was used to evaluate clinical and functional outcomes at 1 to 6 months postoperatively.Introduction:
Methods:
Patient specific instrumentation (PSI) generates customized guides from a magnetic resonance imaging based preoperative plan for use in total knee arthroplasty (TKA). PSI software must be able to accommodate differences in implant design. The purpose of the present study was to determine whether any differences in the accuracy of limb alignment, component alignment, component sizing, or bony resection could be identified in patients undergoing PSI TKA with identical PSI software and one of two different implant systems. In this case-control study, two different implant systems from the same manufacturer were evaluated in 37 consecutive PSI TKA (Group 1) and 123 consecutive PSI TKA (Group 2) performed by a single surgeon. A third group (Group 3) consisted of 12 consecutive TKA performed with manual instrumentation and the same implant system as Group 1. Identical software was used to generate a preoperative plan from which planned limb alignment, component alignment, component sizes, and bony resection were determined. Intraoperatively, actual component sizes, bony resection, and recut frequency were determined. Long-standing and lateral radiographs were obtained preoperatively and 4-weeks postoperatively to evaluate limb and component alignment.Introduction:
Methods:
Patient specific instrumentation (PSI) is an innovative technology in total knee arthroplasty (TKA). With the use of a preoperative MRI or CT scan, custom guide blocks are individually manufactured for each patient. Contrary to other TKA technologies such as computer-assisted surgery, PSI utilises measured resection technique rather than a primarily ligament balancing technique. This has the potential to negatively affect the operating surgeon's ability to achieve optimal soft tissue balancing, which is especially critical in patients with severe lower extremity malalignment. Despite early research suggesting that PSI is accurate, has a low learning curve, and can reduce operating room time, it remains unclear whether a surgeon using PSI can achieve optimal soft tissue balancing using a measured resection technique. The purpose of this study is to evaluate the efficacy of PSI in patients with severe preoperative limb alignment deformities. Fifty PSI total knee arthroplasties were performed on 46 patients (21 male, 25 female) using the Zimmer NexGen Patient Specific Instrumentation system. Each patient included in the study had a minimum preoperative deformity of at least 10° varus or valgus measured on preoperative long leg standing radiographs, Zimmer preoperative software or both. Forty-three of the included knees had a varus deformity and 7 had a valgus deformity. Preoperative mechanical axis alignment measurements were obtained using the PSI preoperative planning software and were manually calculated using preoperative long leg standing radiographs. Postoperative mechanical axis alignment measurements were calculated using plain long leg standing radiographs. The Knee Society Scoring System was used to evaluate clinical and functional outcomes at 1 to 6 months postoperatively.Introduction
Methods
Modular femoral necks have shown promising clinical results in total hip arthroplasty (THA) to optimize offset, rotation, and leg length. Given the wide variety of proximal femoral morphology, fine-tuning these kinematic parameters can help decrease femoroacetabular impingement, decrease wear rates and help prevent dislocations. Yet, additional implant junctions introduce additional mechanisms of failure. We present two patients who developed an abnormal soft tissue reaction consistent with a metal hypersensitivity reaction at a modular femoral neck/stem junction requiring revision arthroplasty. Two patients underwent THA for primary osteoarthritis with the same series of components: 50 mm shell, a 36 mm highly-crosslinked polyethylene liner, uncemented titanium alloy modular stem with a 130 degree Cobalt Chromium (CoCr) modular femoral neck, and 36 mm CoCr head with a +5-mm offset. Patient 1 was a 63 year-old female who had an uneventful post-operative course but presented seven months later with progressive pain in the left hip. Patient 2 was an 80 year-old female who did well post-operatively, but presented with limp and persistent pain at 10 months post-op. An initial evaluation of a painful THA to rule out aseptic loosening, infection, mal-positioning, loosening and osteolysis included radiographs, lab work (CBC, ESR, CRP, Cobalt & Chromium levels) and Metal Artifact Reduction Sequence (MARS) MRI.Introduction
Methods
Patient specific instruments (PSI) and computer-assisted surgery (CAS) are innovative technologies that offer the potential to improve the accuracy and reproducibility with which a total knee arthroplasty (TKA) is performed. It has not been established whether clinical, functional, or radiographic outcomes between PSI, CAS, and manual TKA differ in the hands of an experienced TKA surgeon. The purpose of this study was to evaluate clinical, functional and radiographic outcomes between TKA performed with PSI, CAS, and manual instruments at short-term follow-up. Our hypothesis was that at early follow-up, we would be unable to elucidate any significant differences between the groups using the most commonly utilized outcomes measures. 40 PSI, 38 CAS, and 40 manual TKA were performed by a single surgeon. The groups were similar in regards to age, sex, and preoperative diagnosis. The Knee Society Scoring System was used to evaluate patient clinical and functional outcome scores preoperatively and at 1 and 6 months postoperatively. Long-standing AP radiographs were obtained pre and postoperative to evaluate mechanical axis alignment.Introduction
Methods
Proper femoral component rotation is a crucial factor in successful total knee arthroplasty (TKA). Femoral component rotation using anatomic landmarks has traditionally been established by referencing the transepicondylar axis (TEA), Whiteside's Line (WSL), or the posterior condylar axis (PCA). TEA is thought to best approximate the flexion-axis of the knee, however WSL or PCA are commonly used as surrogates of the TEA in the operating room due to their accessibility. The relationship of these anatomic landmarks has been previously investigated in anatomic and computed tomography based studies. The relatively few knees evaluated have limited the power of these studies. Patient Specific Instrumentation (PSI) utilizing magnetic resonance imaging (MRI) is an emerging technology in total knee replacement. The purpose of this study was to use magnetic resonance imaging based planning software to assess the relationship of WSL and PCA to the TEA and to determine if the relationships were influenced by the magnitude of the pre-operative coronal deformity. Five hundred sixty total knee replacements were performed in 510 patients utilizing PSI. The Materialize preoperative planning software was utilized to determine the rotational relationships of TEA, WSL, and PCA (Fig 1). The coronal plane deformity of each patient was also evaluated utilizing the MRI-based imaging and planning software.Introduction
Methods
Both-bone diaphyseal forearm fractures constitute up to 5.4% of all fractures in children under 16 years of age in the United Kingdom. Most can be managed with closed reduction and cast immobilisation. Surgical fixation options include flexible intramedullary nailing and plating. However, the optimal method is controversial. The main purpose of this study was to systematically search for and critically appraise articles comparing functional outcomes, radiographic outcomes and complications of nailing and plating for both-bone diaphyseal forearm fractures in children.Background
Objectives
Indications for the use of external fixation include damage control orthopaedics, definitive fracture treatment, deformity correction and leg lengthening. Despite many advances in the development of external fixation techniques, pin-tract infection and loosening are still significant complications. They are the most commonly occurring complications during limb lengthening using external fixation, with some studies reporting an incidence of up to 80%. The main aim of this systematic review was to investigate HA-coated versus uncoated external fixator pins used in patients undergoing leg lengthening and determine benefits in terms of pin loosening, infection and loss of reduction/malunion.Introduction
Objectives
Acute achilles tendon ruptures are increasing in incidence and occur in 18 per 100 000 people per year, however there remains a lack of consensus on the best treatment of acute ruptures. Randomised studies comparing operative versus non-operative treatment show operative treatment to have a significantly lower re-rupture rate, but these studies have generally used non-weight bearing casts in the non-operative group. Recent series utilizing more aggressive non-operative protocols with early weight-bearing have noted a far lower incidence of re-rupture, with rates approaching those of operative management. Weight bearing casts may also have the advantages of convenience and an earlier return to work, and the purpose of this study was to compare outcomes of traditional casts versus Bohler-iron equipped weight-bearing casts in the treatment of acute Achilles tendon ruptures. 83 patients with acute Achilles tendon ruptures were recruited from three Auckland centres over a 2 year period. Patients were randomised within one week of injury to receive either a weight-bearing cast with a Bohler iron or a traditional non weight-bearing cast. A set treatment protocol was used, with a total cast time of eight weeks. Patients underwent detailed muscle dynamometry testing at 6 months, with further follow up at 1 year and at study completion. Primary outcomes assessed were patient satisfaction, time to return to work, and overall re-rupture rates. Secondary outcomes included return to sports, ankle pain and stiffness, footwear restrictions, and patient satisfaction. There were no significant differences in patient demographics or activity levels prior to treatment. At follow up, 1 patient (2%) in the Bohler iron group and 2 patients (5%) in the non weight bearing group sustained re-ruptures (p=0.62). There was a trend toward an earlier return to work in the weight-bearing group, with 58% versus 43% returning to work within 4 weeks, but the difference was not significant. 63% of patients in the weight bearing group reported freedom from pain at 12 months compared to 51 % in the non weight bearing group. There were no statistically significant differences in Leppilahti scores, patient satisfaction, or return to sports between groups. Weight-bearing casts in the non-operative treatment of Achilles tendon ruptures appear to offer outcomes that are at least equivalent to outcomes of non-weight bearing casts. The overall rerupture rate in this study is low, supporting the continued use of initial non-operative management in the treatment of acute ruptures.
Recent studies indicated that the knee has a single flexion/extension axis but debated the location of this axis. The relationship of the flexion/extension axis in the coronal plane to the mechanical axis has received little attention. The purpose of this study was to investigate the relationship of the various axes and references with respect to the mechanical axis in the coronal plane Subjects were prospectively scanned into a Virtual Bone Database (Stryker Orthopaedics, Mahwah, NJ). Database is a collection of body CT scans from subjects collected globally. Only CT Scans that met the following qualifications were accepted: ≤1 mm voxels and had slice thickness that was equal to the spacing between the slices (≤ 1.0mm). For each CT Scan, a frontal plane was created through the 2 most posterior points of the medial/lateral condyles and the most posterior point of the trochanter. Then, a transverse plane was created perpendicular to the frontal plane and bisects the 2 most distal points on the medial/lateral condyles. Finally, a saggital plane was created that was perpendicular to the frontal and transversal planes. The following axes were identified: Mechanical Axis of the Femur (MAF) (line between the center of the femoral head and the center of the knee sulcus); Transepicondylar Axis Posterior Cylindrical Axis (PCA) (line between the Medial/Lateral Condylar Circle – best fit circle to three points identified on surface). Measurements made: Angle of MAF and the Joint-Line (Femoral Joint Angle), Angle of the MAF and the Transepicondylar Axis (Femoral TE Angle), and Angle of the MAF and the Posterior Cylindrical Axis (Femoral PC angle). Angles measuring 90° were neutral or perpendicular to the MAF. Angles measured <90° were valgus and >90° were varus.INTRODUCTION
MATERIALS AND METHODS
Many studies have looked at the effects of titanium tibial baseplates compared to cobalt chrome baseplates on backside wear. However, the surface finish of the materials is usually different (polished/unpolished) [1,2]. Backside wear may be a function not only of tray material but also of the locking mechanism. The purpose of this study was to evaluate the wear performance of conventional polyethylene inserts when mated with titanium tibial trays or cobalt chrome tibial trays that both have non-polished topside surfaces. Three titanium (Ti) trays were used along with three cobalt chrome (CoCr) trays. The Ti trays underwent Type II anodization prior to testing. All trays were Triathlon® design (Stryker Orthopaedics, Mahwah, NJ). Tibial inserts were manufactured from GUR 1020 conventional polyethylene then vacuum/flush packaged and sterilized in nitrogen (30 kGy). Appropriate sized CoCr femoral components articulated against the tibial inserts (Triathlon®, Stryker Orthopaedics, Mahwah, NJ). Surface roughness of the tibial trays was taken prior to testing using white light interferometry (Zygo Corp, Middlefield, CT). A 6-station knee simulator (MTS, Eden Prairie, MN) was used for testing. Two phases were conducted. The first phase used a normal walking profile, as dictated by ISO 14243-3 [3]. The second phase used waveforms created specifically for stair climbing kinematics. Testing was conducted at a frequency of 1 Hz for 2 million cycles for each test with a lubricant of Alpha Calf Fraction serum (Hyclone Labs, Logan, UT) diluted to 50% with a pH-balanced 20-mMole solution of deionized water and EDTA (protein level = 20 g/l) [4]. The serum solution was replaced and inserts were weighed for gravimetric wear at least every 0.5 million cycles. Standard test protocols were used for cleaning, weighing and assessing the wear loss of the tibial inserts [5]. Soak control specimens were used to correct for fluid absorption with weight loss data converted to volumetric data (by material density). Statistical analysis was performed using the Student's t-test (p<0.05).INTRODUCTION
MATERIALS AND METHODS
Computer-assisted surgery (CAS) is a tool developed to allow accurate limb and implant alignment in TKA. The strength of the technology is that it allows the surgeon to assess soft tissue balance and ligament laxity in flexion and extension. The accuracy of this ligament balancing technology depends upon an accurate determination of femoral component size. This size is established with intraoperative surface registration techniques. Customized instrumentation (CI) is a measured resection technique in which component size is established on preoperative 3D MRI reconstructions. The purpose of this study is to determine how these two computer-based technologies compare with regard to the accuracy with which femoral component size is established in TKA. 67 TKA were performed using CI and 30 TKA were performed using CAS by a single surgeon. CI-predicted and CAS-predicted femoral component size were compared to actual component selection. The process by which CI and CAS perform an anatomic registration was evaluated.Introduction
Methods
Single use instrumentation had a significant reduction on OR Turnover time and instrument setup/clean up time compared to traditional instrumentation. Recently, focus has shifted to improving OR efficiency by surgeons and hospital admin. The purpose of this study was to determine the effect of traditional instrumentation vs. single use instrumentation (SUI) on OR efficiency in navigated primary TKA.Summary
Introduction
Joint reconstruction remains a successful and popular surgery with advances in approaches, implants and techniques continually forthcoming. Various methods of skin closure exist to address issues in efficiency, aesthetics, and barrier to infection. While subcuticular skin closure techniques offer an aesthetic advantage to conventional skin stapling, no measurable differences have been reported. Furthermore, newer barbed sutures, such as the V-loc absorbable suture, A retrospective chart review was conducted of 278 consecutive primary joint reconstruction cases performed by a single surgeon in 12 months from July 2009 through June 2010. Pre-operative history & physical reports were evaluated for co-morbidities (i.e diabetes mellitus), smoking status and body mass index (BMI). Operative dictations by the attending surgeon provided information on the surgical procedure, use of drain, wound closure technique and type of suture/staple used for skin closure. Skin was closed by the primary surgeon and his chief resident. Wounds were closed via staple gun or subcuticular stitch (3-0 Biosyn vs V-Loc) in a consecutive manner, depending on the surgeon's preference in that period. Post-operative clinic notes were reviewed to determine the occurrence of wound complications, issuance of antibiotic prescriptions, or return to the operating room. The cohort consisted of 106 males and 161 females at an average age of 63 years (range: 18–92). Overall, there were 153 procedures at the knee (including TKA, uni-compartmental arthroplasty, patello-femoral arthroplasty) and 125 procedures at the hip (including THA and hemi-arthroplasty).Introduction
Methods & Materials
