Background. The surgical management of musculoskeletal tumours is a challenging problem, particularly in pelvic and diaphyseal tumour resection where accurate determination of bony transection points is extremely important to optimise oncologic, functional and reconstructive options. The use of
Surgical training has been greatly affected by the challenges of reduced training opportunities, shortened working hours, and financial pressures. There is an increased need for the use of training system in developing psychomotor skills of the surgical trainee for fracture fixation. The training system was developed to simulate dynamic hip screw fixation. 12 orthopaedic senior house officers performed dynamic hip screw fixation before and after the training on training system. The results were assessed based on the scoring system that included the amount of time taken, accuracy of guide wire placement and the number of exposures requested to complete the procedure. The result shows a significant improvement in amount of time taken, accuracy of fixation and the number of exposures after the training on simulator system. This was statistically significant using paired student t-test (p-value <0.05). Computer navigated training system appears to be a good training tool for young orthopaedic trainees The system has the potential to be used in various other orthopaedic procedures for learning of technical skills aimed at ensuring a smooth escalation in task complexity leading to the better performance of procedures in the operating theatre.
To confirm whether developmental dysplasia of
the hip has a risk of hip impingement, we analysed maximum ranges
of movement to the point of bony impingement, and impingement location
using three-dimensional (3D) surface models of the pelvis and femur
in combination with 3D morphology of the hip joint using computer-assisted methods.
Results of computed tomography were examined for 52 hip joints with
DDH and 73 normal healthy hip joints. DDH shows larger maximum extension
(p = 0.001) and internal rotation at 90° flexion (p <
0.001).
Similar maximum flexion (p = 0.835) and external rotation (p = 0.713)
were observed between groups, while high rates of extra-articular
impingement were noticed in these directions in DDH (p <
0.001).
Smaller cranial acetabular anteversion (p = 0.048), centre-edge
angles (p <
0.001), a circumferentially shallower acetabulum,
larger femoral neck anteversion (p <
0.001), and larger alpha
angle were identified in DDH. Risk of anterior impingement in retroverted
DDH hips is similar to that in retroverted normal hips in excessive
adduction but minimal in less adduction. These findings might be
borne in mind when considering the possibility of extra-articular
posterior impingement in DDH being a source of pain, particularly
for patients with a highly anteverted femoral neck. Cite this article:
We have investigated the benefits of patient
specific instrument guides, applied to osteotomies around the knee. Single,
dual and triple planar osteotomies were performed on tibias or femurs
in 14 subjects. In all patients, a detailed pre-operative plan was
prepared based upon full leg standing radiographic and CT scan information.
The planned level of the osteotomy and open wedge resection was
relayed to the surgery by virtue of a patient specific guide developed
from the images. The mean deviation between the planned wedge angle
and the executed wedge angle was 0° (-1 to 1, Cite this article:
Abstract. Introduction. Component mal-positioning in total hip replacement (THR) and total knee replacement (TKR) can increase the risk of revision for various reasons. Compared to conventional surgery, relatively improved accuracy of implant positioning can be achieved using
Study design. Literature review of the best available evidence on the accuracy of
Background: The use of sacro-iliac screws to restore the stability of posterior pelvic ring dissociations has become a standard technique. Several methods are described including fluoroscopy, CT and
Introduction: Obesity [Body Mass Index (BMI) >
30] is seen in a growing percentage of patients seeking joint replacement surgery. Recent studies have shown no clear influence of obesity on the five-year, clinical outcome of total knee replacement; except for the morbidly obese (BMI >
40). Computer navigation has shown improved consistency of prosthetic component alignment. However, this aid does significantly increase operation time. Aims:. To compare tourniquet times of standard and
We present minimum 20 year results of a randomized, prospective double blinded trial (RCT) of cross-linked versus conventional polyethylene (PE), using a
Since 2000 we have performed TKR with the aid of a
Background. Limb length discrepancy after total hip replacement is one of the possible complications of suboptimal positioning of the implant and cause of patients dissatisfaction.
Background. Stress fractures at tracker after computer navigated total knee replacement are rare. Periprosthetic fracture after Minimally Invasive Plate Osteosynthesis (MIPO) of stress fracture through femoral tracker is unique in orthopaedic literature. We are reporting this unique presentation of periprosthetic fractures after MIPO for stress fracture involving femoral pin site track in
Introduction. Post traumatic arthritis of the knee can be a conseguence of distal femur fracture and retained hardware can complicate any further surgical option including arthroplasty. Both staged surgical procedures to remove before the hardware or simultaneous procedure of arthroplasty and removal of hardware have been indicated with an increased risk of complications. Aim of this study is to present a consecutive series of TKA following distal femur fracture using a
To prospectively evaluate the accuracy as well as patient outcome of computer-assisted total knee replacement in a multi-centric randomised study. Two hundred and ninety-five patients in six European centers were randomised between two groups: One hundred and forty-seven in the conventional surgery group and one hundred and forty-eight in the
Objective:. Periacetabular spherical osteotomy for the treatment of dysplastic hip is effective but technically demanding. To help surgeons perform this difficult procedure reliably and safely, a
Introduction: There has been significant development in computer technology in recent years and this has led to applications in orthopaedic surgery. Of particular interest is
To determine the precision of conventional versus
Two
Two
Stereotactic principles used primarily for brain surgery have been developed further and introduced into spine surgery at the beginning of the 1990’s. The system solutions available consist of three components: the surgical object (vertebra), the virtual object (CT-image data of the vertebra), and the navigatorallowing the surgeon to localise the position of the instrument inside the surgical object in real-time. Optoelectronic systems using infrared light emitting diodes and magnetic field based navigators are in use. Lumbar pedicle screw insertion was the first clinical application for this technique. Screws can be positioned safely following a preplanned optimal trajectory or according to the anatomic situation utilising the real-time module intraoperatively. The effectiveness of this new technique has been shown in prospective studies (Schwarzenbach et al 1997, Laine et al 1997, 1999). In a a prospective randomised clinical trial one-hundred consecutive patients were randomly allocated for either conventional (Group 1) or
To describe our experience with
Computer navigation was introduced in Australia in 2000, initially with the use of pre-operative computer scans and then later with image free systems. In 2003 the AOA – NJRR began collecting data for knee replacement performed with computer navigation. Meta analysis of the literature has shown better coronal and sagittal plane alignment in total knee arthroplasty performed with computer navigation as opposed to standard instrumented knee replacement. At present, however, there is no data on improved outcomes or reduced revision rates. Information was requested from the AOA – NJRR on the use of computer navigation for both uni-compartmental and total knee replacements. This included numbers of navigated knees done per year as well as revision rates and reasons for revisions of knees performed by computer navigation surgery. Since data collection began there has been 2,651
Aims: To determine the precision of conventional versus
Minimally invasive total hip replacement surgery not only decreases the number of visual cues necessary for proper acetabular component position, the small incision makes it technically more difficult to use traditional mechanical alignment guides. Furthermore, traditional mechanical guides have been shown to be unable to accurately predict component position as determined by intraoperative computer measurements.[ 1,2 ]
Introduction: The purpose of this study was to compare two methods for the quantification of bone marrow edema (BME) of the knee. Materials and Methods: Forty-one patients with Bone Marrow Edema (BME) of the knee due to osteonecrosis, osteoarthritis, bone bruise or stress were included in the study. Coronal STIR images of the affected knees were obtained using either a 1.0 Tesla or a 1.5 Tesla Magnetic Resonance (MR) scanner. To monitor the BME’s progression, every knee was examined twice at a 3-month interval. Size and signal intensity of BME were semi-quantitatively assessed in consensus by two radiologists and two orthopaedic surgeons. Independently, size and signal intensity were calculated using a new
Purpose: Use of six-axis analysis and
Introduction The aim of this study was to compare the new technique of
The aim of the study was to determine the precision of conventional versus computer-assisted techniques for positioning the acetabular component in total hip arthroplasty (THA). Malposition of the acetabular component during THA increases the occurrence of impingement, reduces range of motion, and increases the risk of dislocation and long-term wear. To prevent malpositioned hip implants, an increasing number of
The most reported benefit of TKA navigation technologies has been the reduction in limb and component alignment outliers. This improvement has not been shown to effect clinical outcomes. This study was designed to compare the functional outcomes between
Unicompartment knee arthroplasty (UKA) was proven to be one of the standard treatments of medial compartment osteoarthritis. The key to success was restoration of pre-operative alignment. Overcorrection of coronal (AP) alignment may predispose to early osteoarthritis in the contralateral compartment, change in post-operative tibial slope may predispose to proximal tibial bone collapse and loosening of tibial prosthesis. Minimally invasive surgery (MIS) in UKA was developed quickly in the last ten years. However, MIS has limited access to visualize the surgical field and limb alignment. Computer navigation may help the surgeon to place the component in more accurate position. We aim to study the radiological alignment of
Aims: Computer guidance has improved the accuracy and safety of pedicle screw insertion. The aim of this study was to evaluate whether CT-based
Introduction: Computer navigated total knee replacement does not require the use of intramedullary alignment rods, and is thus less invasive than traditional methods. One previous study has suggested that the computer-assisted technique may reduce blood loss in comparison to traditional methods. This study (. Kalairajah et al, 2005. ) used blood volume loss from drainage bottles as a primary outcome measure (n=60). Hidden (internal) blood losses were not accounted for. Our study uses a more accurate method of assessing blood loss, and the sample size is larger (n=136; 68 standard TKR versus 68
Studies suggest that specialty hospitals and high surgical volume decrease adverse outcomes related to hip arthroplasty. Little is known, however, concerning the influence of imageless computer navigation systems on a surgeon’s experience and subsequent placement of implants in the setting of hip resurfacing arthroplasty. A retrospective review of 71 consecutive hip resurfacing arthroplasties placed with
INTRODUCTION. Despite clear clinical advantages Unicompartimetal Knee Replacement (UKR) still remain a high demanding and less forgiving surgical procedure. Different Authors in literature pointed out how in coronal tibial malalignment beyond 3° as well as tibial slope beyond 7° increase the rate of aseptic failure. Likewise, overcorrection in the coronal plain is a well recognised cause of failure because of an overweighting on the controlateral compartment. Furthermore it has been shown how in UKR surgery even using short narrow intramedullary guide this can cause errors in both coronal planes.
Introduction. Total hip arthroplasty has become an increasingly common procedure. Improper cup position contributes to bearing surface wear, pelvic osteolysis, dislocations, and revision surgery. The incidence of cup malposition outside of the safe zone (40° ± 10° abduction and 15° ± 10° anteversion) using traditional techniques has been reported to be as high as 50%. Our hypothesis is that
INTRODUCTION. Nowadays, longevity of total knee arthroplasties is very acceptable. Survivorship analyses demonstrate a success in a range of 80% to more than 95% over a period of more than ten years (1–4). However, long-term results largely depend, amongst other factors, on restoration of physiological alignment of the lower limb (5–11). Jeffery et al. (12) reported a three percent loosening rate over eight years when knees were correctly aligned whereas insufficient alignment lead to prosthetic loosening in 24 percent. Rand and Coventry (13) found a 90 percent survivorship rate at ten years when the mechanical axis was aligned in a range from nought to four degrees of valgus. Valgus position of more than four degrees or varus alignment resulted in only 71 percent and 73 percent of survivorship respectively. Recently, computer aided instrumentation systems (14,15) became available and preliminary results of small series were reported (16–17). The purpose of this study was to assess the accuracy of computer integrated instrumentation for knee alignment. MATERIAL AND METHOD. The OrthoPilot. ®. represents a computer controlled image supported alignment system. A 3-D Optotrak™ camera localizes infra-red diodes fixed to rigid bodies within the surgical field. Thereby a spatial coordinate reference system is provided. The localizer is linked to a UNIX work station which performs the operative protocol using a graphical interface and a foot pedal. The rigid bodies are fixed to the bones by bicortical screws. An intraoperative kinematic analysis and various additional landmarks lead to definition of the centres of hip, ankle and knee joint and sizing of endoprosthetic components. With the use of LED-equipped alignment instruments the femoral and tibial resection planes are determined. The OrthoPilot. ®. navigation system is not dependant on CT data and no additional preoperative planning is therefore necessary. A prospective comparative multicentre study in five institutions, four in Germany and one in France, was carried out. 821 patients with primary tricompartimental knee arthroplasty using the SEARCH LC knee (B|Braun AESCULAP) were included in the study. The OrthoPilot. ®. Navigation system was used in 555 cases and 266 knees were implanted with the use of conventional instrumentation. At the three months follow-up alignment was assessed using standardized one leg stance radiographs with regard to the mechanical axis and the femoral and tibial angels in the coronal plane. For the lateral femoral and tibial angels standard lateral x-rays were used. Prosthetic alignment was verified by an independent observer. RESULTS. The radiographically assessed results were subdivided into three groups. An error of ± one degree in the radiographical measurements and small deviations caused by the play of surgical instruments have to be considered. With respect to the femoral and tibial angels in the ap and lateral view the group of very good clinical results was, therefore, defined in the range between ninty degrees and ± two degrees. Deviations of three and four degrees from the optimum were classified as being clinically acceptable. Aberrations of more than four degrees were classified as outliers. When measuring the mechanical axis deviations from fully precise femoral and tibial angels may add up. For this reason zero degrees ± three degrees were rated as a very good result, deviations of four to five degrees were considered to be acceptable and alignment beyond five degrees from the optimum was classified as an unsatisfactory result. Mechanical axis:. 35. 2% of the navigated cases were aligned at exactly zero degrees. This was achieved in only 24. 4% of the manual cases. 88. 6% of cases using navigation and 72. 2% in the manual group showed zero degrees and varus or valgus angles of up to three degrees. 8. 9% and 18. 1% of cases respectively showed deviations of four or five degrees of valgus or varus alignment representing an acceptable clinical result. In only 2. 5% of the navigation group aberrations of more than five degrees occurred. The rate of dissatisfying results was 9. 8% in the manual group. Femoral axis (coronal plane):. In the navigation group 48. 1% of cases showed an alignment at exactly 90 degrees which was the case in only 33. 5% of the control group. Altogether, in 89. 4% of the navigated cases a very good result was observed. In the conventionally instrumented cases only 77. 1% very good results were found. There were 1. 6% outliers beyond the limits of four degrees in the navigation group in comparison to 4. 9% amongst the control cases. Femoral axis (sagittal plane):. Very good results with up to two degrees of deviation from a ninety degree position were obtained in 75. 5% of navigated cases and 70. 7% of manual cases. 37. 3% and 34. 6% respectively showed an ideal alignment of exactly ninety degrees. Unsatisfactory results were observed in 9. 5% of the navigated cases and 9. 4% of the manual cases. Tibial axis (coronal plane):. 58. 7% of the
Restoring the overall mechanical alignment to neutral has been the gold standard since the 1970s and remains the current standard of knee arthroplasty today. Recently, there has been renewed interest in alternative alignment goals that place implants in a more “physiologic” position with the hope of improving clinical outcomes. Anywhere from 10 – 20% of patients are dissatisfied after knee replacement surgery and while the cause is multifactorial, some believe that it is related to changing native alignment and an oblique joint line (the concept of constitutional varus) to a single target of mechanical neutral alignment. In addition, recent studies have challenged the long held belief that total knee placed outside the classic “safe zone” of +/− 3 degrees increases the risk of mechanical failure which theoretically supports investigating alternative, more patient specific, alignment targets. From a biomechanical, implant retrieval, and clinical outcomes perspective, mechanical alignment should remain the gold standard for TKA. Varus tibias regardless of overall alignment pattern show increased polyethylene wear and varus loading increases the risk of posteromedial collapse. While recently questioned, the evidence states that alignment does matter. When you combine contemporary knee designs placed in varus with an overweight population (which is the majority of TKA patients) the failure rate increases exponentially when compared to neutral alignment. A recent meta-analysis on mechanical alignment and survivorship clearly demonstrated reduced survivorship for varus-aligned total knees. The only way to justify the biomechanical risks associated with placing components in an alternative alignment target is a significant clinical outcome benefit but the evidence is lacking. A randomised control trial comparing mechanical alignment (MA) and kinematic alignment (KA) found a significant improvement in clinical outcomes and knee function in KA patients at 2 year follow-up. In contrast, Young et al. recently published a randomised control trial comparing PSI KA and
INTRODUCTION. Total knee replacement is mostly done with alignment rods in order to achieve a proper Varus / Valgus alignement. Other techniques are
Introduction. Recently, tibial insert design of cruciate-substituting (CS) polyethylene insert is employed and widely used. However, in vivo kinematics of using CS polyethylene insert is still unclear. In this study, it is hypothesized that CS polyethylene insert leads to stability of femoro-tibial joint as well as posterior-stabilized (PS) polyethylene insert, even if PCL is sacrificed after TKA. The purpose of this study is an investigation of in vivo kinematics of femoro-tibial joint with use of CS polyethylene insert before and after PCL resction using
Introduction.
The advantages of computer navigated total knee replacement are well documented in the literature, however, increased surgical time and cost issues remain the major deterrent for the wide use of this technology. Placement of cutting jigs under computer guidance forms a major aspect of
There have been mixed reports of the contribution of the anterior cruciate ligament (ACL) to the overall envelope of tibial rotational stability. The effect of single bundle ACL reconstruction on the separate components of internal and external rotational stability respectively is also unclear. We determined the internal and external rotation, and antero-posterior movement of the knee before and after single bundle
Introduction. Recently, tibial insert design of cruciate-substituting (CS) polyethylene insert is employed. However, in vivo kinematics of using CS polyethylene insert is still unclear. In this study, it is hypothesized that CS polyethylene insert leads to stability of femolo-tibial joint as well as posterior-stabilized (PS) polyethylene insert, even if PCL is sacrificed after TKA. The purpose of this study is an investigation of in vivo kinematics of femolo-tibial joint with use of CS polyethylene insert before and after PCL resction using
Reconstructive knee arthroplasty in patients with limb deformity can be a daunting and complex task. These patients are often younger and so post traumatic osteoarthritis poses a real challenge. In view of their relative youth, bone preservation would be favourable; however accurate implantation of components is essential. Formulation of a well calculated plan and accurate execution is essential for successful surgery. We report on a novel method which combines 3D CT joint analysis and computer navigation to define the deformity present pre-operatively and determine whether the proposed reconstruction is feasible. If the reconstructive surgery is feasible, an accurate calculation the correction required is performed. The planned surgery is executed using computer aided navigation surgery. Eight patients have benefited from the technique. Four patients presented with isolated medial compartment osteoarthritis and intact anterior cruciate ligament. These patients underwent 3D CT joint analysis and
This preliminary study concerns the results of THR using a minimally invasive
Recent studies suggest the use of computer navigation during TKA can reduce intraoperative blood loss. The purpose of this study was to assess if navigation affected blood loss after TKA in the morbidly obese patient (BMI>
40). Total body blood loss was calculated from body weight, height and haemotocrit change, using a model which accurately assess true blood loss. The computer navigated group comprised of 60 patients, 30 with BMI >
40 and 30 with BMI<
30. The matched conventional knee arthroplasty group consisted of 62 consecutive patients, 31 with BMI>
40 and 31 with BMI<
30 The groups were matched for age, gender, diagnosis and operative technique. Following TKA, the mean total loss was 1014mls (521-1942, SD 312) in the