One main perceived drawback for the adoption of computer assisted orthopedic surgery (CAOS) during total knee arthroplasty (TKA) relates to the increased surgical time compared to the use of standard mechanical instrumentation [1]. This study compared the time efficiency between a next generation CAOS system (ExactechGPS®, Blue-Ortho, Grenoble, FR) and conventional mechanical instrumentation, and assessed the impact of surgeon experience level on the efficiency. Surgical time was retrospectively reviewed on 63 primary TKAs performed by a board-certified orthopedic surgeon (PP) using a cemented postero-stabilized knee system (Optetrak Logic PS, Exactech, Gainesville, FL), grouped as 1) Group I (control): 21 TKAs using conventional mechanical instruments; 2) Group II: 21 TKAs performed using the CAOS system with an early experience level (first 21 cases); and 3) Group III: 21 TKAs using the CAOS system with an advanced experience level (beyond 30 cases). Surgical time was compared across the three groups (with significance defined as p<0.05).Introduction
Materials and methods
One main perceived drawback for the adoption of computer assisted orthopaedic surgery (CAOS) during total knee arthroplasty (TKA) relates to the increased surgical time compared to the use of standard mechanical instrumentation. This study compared the time efficiency between a next generation CAOS system (ExactechGPS®, Blue-Ortho, Grenoble, FR) and conventional mechanical instrumentation, and assessed the impact of surgeon experience level on the efficiency. Surgical time was retrospectively reviewed on 63 primary TKAs performed by a board-certified orthopaedic surgeon (PP) using the Optetrak Logic® PS knee system (Exactech, Gainesville, FL), grouped as 1) Group I (control): 21 TKAs using conventional mechanical instruments; 2) Group II: 21 KAs performed using the CAOS system with an early experience level (first 21 cases); and 3) Group III: 21 TKAs using the CAOS system with an advanced experience level (beyond 30 cases). Patient condition (age, BMI, gender, etc.), surgical technique, and post-operative guidelines were similar across the three groups. No cases were lost and no patient had any intra-operative complications. Surgical time was compared across the three groups (with significance defined as p<0.05). Compared to the TKAs using conventional mechanical instrumentation, the average surgical time for the navigated TKAs performed with an early experience was 7 minutes longer. However, with an advanced experience level, the average surgical time was 2 minutes less than the time required using conventional mechanical instrument. Further, navigated TKAs with an advanced experience level exhibited the least variability among the three groups. None of the time differences were significant (p>0.20). No significant difference in TKA surgical time was found between the evaluated CAOS system (both within or pass the learning curve) and the conventional instrumentation. Nevertheless, once the learning curve was reached, the system decreased the time variability compared to conventional mechanical instrumentation. The comparable efficiency reported in this study to the conventional mechanical instrumentation may be attributed to the unique features of the ExactechGPS system, such as indication for use inside the sterile field, blood occlusion-resistant tracker design, customisable operative technique tailored to the surgeon's preference, and compact and reduced number of instruments.
From pre-operative planning to final implant cementation, total knee arthroplasty (TKA) preparation is a succession of many individual steps, each presenting potential sources of error that can result in devices being implanted outside the targeted range of alignment. This study assessed alignment discrepancy occurring during different TKA steps using an image-free computer-assisted orthopaedic surgery (CAOS) guidance system (Exactech GPS, Blue-Ortho, Grenoble, FR) in normal and abnormal mechanical axis. We used a commercially available artificial leg (MITA trainer leg M-00058, Medical Models, Bristol, UK) able to receive (neutral / varus / valgus) knee inserts simulating the proximal tibia and distal femur. A pre-surgical profile was established to define resection parameters for the proximal tibial and distal femoral cuts (Figure 1A). Data from the guidance system were collected at three separate steps: (1) cutting block adjusted but not pinned to the bone (Figure 1B), (2) cutting block adjusted and pinned to the bone (Figure 1C), and (3) after the cuts were checked (Figure 1D). These data were then compared to the resection target parameters to track potential dispersions occurring during the process. Due to the amount of data (i.e., four studied resection parameters per bone, three operative steps, and three knee model types), the authors introduced an “error index”, which was a unitless indication of overall error magnitude obtained by averaging the absolute values of all linear and angular measurement errors. Due to knee model dimensions (∼55 mm), the authors equally considered linear and angular measurement values (i.e., 1 mm equivalent to 1°).Introduction
Materials and methods
An emerging consensus in the surgical specialties is that skill acquisition should be more emphasized during surgical training.1 This study was an attempt to evaluate the effects of repetitive practices using an image-free computer-assisted orthopaedic surgery (CAOS) guidance system (Exactech GPS, Blue-Ortho, Grenoble, FR) on both technical and cognitive skills. A senior knee replacement surgeon with limited previous experience with the CAOS system performed a series of consecutive simulated knee surgeries using a commercially available artificial leg (MITA trainer leg M-00058, Medical Models, Bristol, UK). In order to assess the effects repetitive practice has on technical skills, we evaluated two indexes: Error index: A unitless indication of overall error magnitude obtained by averaging the absolute values of all linear and angular measurement differences between targeted and checked cuts. Time index: An indication of the time required to acquire landmarks, adjust the custom blocks, and make cuts. In order to assess the effect repetitive practice has on cognitive skills, we evaluated the number of times the surgeon elected to deviate from pre-surgical planning or re-acquire landmarks. We evaluated these parameters for three chronological and consecutive groups of simulated surgeries: Group A (knee models #1 to #10), Group B (knee models #11 to #20), and Group C (knee models #21 to #28).Introduction
Materials and methods
Clinical outcomes for total knee arthroplasty (TKA) are especially sensitive to lower extremity alignment and implant positioning.1 The use of computer-assisted orthopaedic surgery (CAOS) can improve overall TKA accuracy.2 This study assessed the accuracy of an image-free CAOS guidance system (Exactech GPS, Blue-Ortho, Grenoble, FR) in both a synthetic leg with a normal mechanical axis and legs with abnormal mechanical axis. A high-resolution 3D scanner (Comet L3D, Steinbichler, Plymouth, MI) was used to scan varus-deformed (n=12), neutral (n=12), and valgus-deformed (n=4) knee inserts (Mita M-00566, M-00598, M-00567; respectively, Medical Models, Bristol, UK) and collect pre-identified anatomical landmarks prior to using the models to simulate knee surgery. The image-free CAOS guidance system was then used to acquire the same landmarks. After adjusting the position and orientation of the cutting block to match the targets, bone resections were performed, and the knee models were re-scanned. The 3D scans made before and after the cuts were overlaid and the resection parameters calculated using the pre-identified anatomical landmark data and advanced software (UG NX, Siemens PLM, Plano, TX). Data sets obtained from the 3D scanner (see Figure 1A) were compared with data sets from the guidance system (see Figure 1B). Given the accuracy of the 3D scanner (<50μm), its measurements were used as the baseline for assessing CAOS system error.Introduction
Materials and methods
From pre-operative planning to final implant cementation, total knee arthroplasty (TKA) can be defined by a succession of individual steps, each presenting potential errors that can result in devices being implanted outside the desired range of alignment. Our study used an image-free computer-assisted orthopedic surgery (CAOS) guidance system (Exactech GPS, Blue-Ortho, Grenoble, FR) to evaluate alignment discrepancies occurring during different steps of a typical TKA procedure. A surgical profile was established to define resection parameters and steps for proximal tibial and distal femoral cuts (see Figure 1A) to be made on seven synthetic knee models (MITA, Medical Models, Bristol, UK). First, the guidance system was used to acquire pre-identified landmarks. Next, a cutting block was adjusted to match the resection targets and then fixed to the bone using locking pins. Bone cuts were performed and then checked. Data was collected from the guidance system at three steps: (1) cutting block adjusted but not pinned to bone (see Figure 1B), (2) cutting block adjusted and pinned to bone (see Figure 1C), and (3) after checking cuts (see Figure 1D). These data were then compared to the resection target parameters to assess potential discrepancies.Introduction
Materials and methods:
Clinical outcomes for total knee arthroplasty (TKA) are especially sensitive to lower extremity alignment and implant positioning.1 The use of computer-assisted orthopedic surgery (CAOS) can improve overall TKA accuracy.2 This study assessed the accuracy of an image-free CAOS guidance system (Exactech GPS, Blue-Ortho, Grenoble, FR) used in TKA. A high-resolution 3D scanner (Comet L3D, Steinbichler, Plymouth, MI) was used to scan seven knee models (MITA, Medical Models, Bristol, UK) and collect pre-identified anatomical landmarks (see Figure 1) prior to using the models to simulate knee surgery. The image-free CAOS guidance system was then used to acquire the same landmarks. After adjusting the position and orientation of the cutting block to match the targets, bone resections were performed, and the knee models were re-scanned. The 3D scans made before and after the cuts were overlaid (see Figure 2) and the resection parameters calculated using the pre-identified anatomical landmark data and advanced software (XOV & XOR, RapidForm, Lakewood, CO and UG NX, Siemens PLM, Plano, TX). Data sets obtained from the 3D scanner were compared with data sets from the guidance system. Given the accuracy of the 3D scanner, its measurements were used as the baseline for assessing CAOS system error.Introduction
Materials and methods:
Clinical outcomes for total knee arthroplasty (TKA) are especially sensitive to lower extremity alignment and implant positioning. The use of computer-assisted orthopedic surgery (CAOS) can improve overall TKA accuracy. This study assessed the accuracy of an image-free CAOS guidance system (Exactech GPS, Blue-Ortho, Grenoble, FR) used in TKA. A high-precision 3D scanner (Comet L3D, Steinbichler, Plymouth, MI) was used to scan seven knee models (MITA, Medical Models, Bristol, UK) and collect pre-identified anatomical landmarks prior to using the models to simulate knee surgery. The Exactech GPS was then used to acquire the same landmarks. After adjusting the Exactech GPS cutting block to match the targets, bone resections were performed, and the knee models were re-scanned. The 3D scans made before and after the cuts were overlaid and the resection parameters calculated using the pre-identified anatomical landmark data and advanced software (XOV & XOR, RapidForm, Lakewood, CO and UG NX, Siemens PLM, Plano, TX). Data sets obtained from the 3D scanner were compared with data sets from the guidance system. Given the accuracy of the 3D scanner, its measurements were used as the baseline for assessing CAOS system error. The CAOS system bone resection measurement errors had an overall mean of less than 0.35 mm. The mean errors for joint angle measurement was less than 0.6°. Even considering the ranges, errors were no more than 1 mm for all bone resection measurements and no more than 1° for all joint angle measurements. The low variability is also supported by small SD values. To our knowledge, this is the first study to use a high-resolution 3D scanner to assess the accuracy of surgical cuts made with image-free CAOS system assistance. Determining precise landmarks using CAOS for TKA has been shown to be of critical importance. For this reason, the anatomical landmarks used by the scanner and guidance system were carefully identified and prepared to ensure consistency. The study demonstrated that the evaluated image-free CAOS system was able to achieve a high level of
Achilles tendinopathy is chronic degeneration of the Achilles tendon, usually secondary to injury or overuse. It involves a triad of pain, swelling and impaired function. Primary treatment is rest, analgesia, corticosteroid injections and physiotherapy (eccentric training and heel pads to correct gait). Some patients remain symptomatic and further treatment options need considering. NICE produced a document from the Interventional Procedures Advisory Committee in 2009 which reviewed the literature and evidence for extracorporeal shockwave treatment (ESWT). Low energy shock wave treatment (SWT) is thought to stimulate soft tissue healing, inhibit pain receptors and promote angiogenesis. NICE guidance was that ESWT could be used in refractory Achilles tendinopathy if used for clinical governance, audit or research. Patients with refractory Achilles tendinopathy were enrolled between October 2010 and 2011. They received three sessions of ESWT over three week. Patients completed visual analogue scale (VAS) scores for pain at rest and on activity and the Victorian Institute of Sport Assessment-Achilles (VISA-A) questionnaire pre-treatment. These outcome measures and a six-point Likert satisfaction scale (six points, high is worsening) were reassessed at 6 and 16 weeks post treatment. 51 patients completed follow up. The mean age was 56 (34–80) years and mean length of symptoms 34 (4–252) months. There was a significant improvement (p<0.05) in VAS scores observed from baseline and 16 weeks post treatment. This was also the case in the VISA-A scores. The mean Likert score was 3 (somewhat improved) at 16 weeks but there was no statistical significance. This study suggests that ESWT improves subjective and objective outcomes in patients with refractory Achilles tendinopathy. Patients over 60 possibly have a worse outcome along with patient who had symptoms for over 25 months. Follow up scores at one year are due to be collected and the data will be submitted to NICE.
Achilles tendinopathy is characterised by chronic degeneration of the Achilles tendon, usually secondary to injury or overuse. Extracorporeal shockwave treatment (ESWT) is of potential benefit in refractory cases where conservative management with analgesia, physiotherapy and corticosteroid injection have been unsuccessful. Patients with refractory Achilles tendinopathy enrolled between October 2010 and October 2011 received three sessions of ESWT over three weeks. Patients completed visual analogue scale (VAS) scores for pain at rest and on activity and the Victorian Institute of Sport Assessment-Achilles (VISA-A) questionnaire pre-treatment. These outcome measures and a six-point Likert satisfaction scale were reassessed at six and 16 weeks post treatment. 51 patients completed follow up. Mean age was 56 (34–80) years and mean length of symptoms 34 (4–252) months. Significant improvement (p<0.05) in VAS scores (rest and activity) and VISA-A scores was observed between baseline and 16 weeks. Mean Likert score was 3 (somewhat improved) at 16 weeks. Patients suffering Achilles tendinopathy for longer than 25 months had significantly less improvement than those affected for a shorter period. This study suggests that ESWT improves subjective and objective outcomes in patients with refractory Achilles tendinopathy.
The aim of this prospective study was to determine the prevalence of bone marrow oedema (BME) in asymptomatic knees of athletes and to investigate the factors associated with appearance of BME in this group. A total of 25 asymptomatic athletes who competed at an international, national or county level during their most recent sport season were recruited in this study and had MRI scan of both knees (n=50). MRI scans were reported independently by two experienced musculoskeletal radiologists. Statistical analysis included Cohen's kappa test to identify inter-observer agreement for MRI diagnosis of bone marrow oedema and multiple logistic regression model to identify the factors associated with BME on MRI scan. There was very good agreement between radiologists for diagnosis of BME (Kappa = 0.896). Seven participants (28%) were found to have BME. Six of the participants had BME in unilateral knees and one participant had BME in bilateral knees. The commonest location of BME was medial femoral condyle (62.5%) The amount of time spent in preseason training (34-38 weeks) was significantly associated with appearance of BME (P=0.048) BME seems to be common in asymptomatic athletes and one should realize that this finding might not be related to the clinical complaints of the patients. The results of the present study show that there is a training effect associated with BME. Knowing what is a ‘normal’ or ‘abnormal’ scan is important for a competitive athlete, as erroneously diagnosing BME as the underlying cause of athletes' symptoms could lead to decreased playing time or inappropriate therapy.
Many radiographic techniques have been described for measuring patellar height. They can be divided into two groups: those that relate the position of the patella to the femur (direct) and those that relate it to the tibia (indirect). This article looks at the methods that have been described, the logic behind their conception and the critical analyses that have been performed to test them.
There is debate regarding the most appropriate treatment of calcific tendinitis. Minimally-invasive techniques with image-guided needling of the deposits have been developed to provide an alternative solution. We present the results of fluoroscopically-guided barbotage in 100 patients. One hundred patients with acute or chronic shoulder pain, visible on plane radiographs or ultrasound scan, were referred from the Orthopaedic Department for barbotage over a six-year period. This study is a retrospective review of the results of barbotage in these patients, using a patient-based questionnaire. Forty three patients ultimately required arthroscopy of their painful shoulder. However, at surgery, the calcific deposits were noted to have dispersed in the majority of these patients. In addition there was often a long symptom-free period between the initial barbotage and recurrence of pain. In many cases the nature of their symptoms had changed and at arthroscopy signs of impingement or rotator cuff tears were common. Barbotage eliminated the need for more invasive surgery in over half of the patients in this study. It should be considered in all patients with calcific tendinitis refractory to non-operative treatment.
The purpose of this study was to assess the clinical outcome of two non-invasive techniques used in the treatment of calcific tendinitis of the shoulder. Over the eight month period April 2000 to November 2000 sixty patients who were referred to this hospital with symptomatic calcific tendonitis were treated either with extracorporeal shockwave therapy (ESWT) using the Storz Medical Minilith (Storz Medical AG, Kreuzlingen, Germany) or by barbotage (needle puncture, aspiration and lavage under ultrasound control). All the patients had a long history of shoulder pain (average 42 months), caused by a radiographically evident calcific deposit, that had been unresponsive to conservative treatment including physiotherapy, steroid injections and non-steroidal anti-inflammatory tablets. 15 patients were treated with ESWT and 45 with ultrasound guided barbotage. The patients undergoing ESWT had the application head positioned under real time ultrasound or flouroscopic control. Patients had from one to three treatments with up to 2,500 shocks per treatment at incremental energy levels from 0.1 to 0.2 mJ/ mm2. Patients undergoing real time ultrasound guided barbotage had a single treatment. Clinical outcome was evaluated after a three month period with a postal questionnaire. Thirty-two of 45 patients (71%) in the barbotage group had a marked reduction in symptoms at three months compared to nine out of 15 (64%) of the ESWT group. Shockwave therapy (ESWT) and ultrasound guided barbotage are simple non invasive outpatient procedures which are effective in 64% to 71% of patients. These simple outpatient techniques should be considered for chronic pain due to calcific deposits that have been unresponsive to conservative treatments, and surgery reserved for those who fail to benefit.
We have studied the case records of 16 patients with dislocations of the cervical spine who deteriorated neurologically during or after reduction. The dislocations were reduced by skull traction in four patients, by manipulation in four and by operation in seven. This complication was not related to age, sex, mechanism of injury, or the level and the type of dislocation. Fourteen patients made substantial recoveries, one made a partial recovery and one patient remained totally paralysed and died three months later. The causes and prevention of spinal-cord damage at this stage of management are discussed, and the early use of MRI or CT myelography is recommended.
We report 13 patients with missed bilateral facet dislocation of the lower cervical spine who subsequently developed severe spinal-cord involvement. There were more women and the patients were older than in most groups with spinal injury. The commonest cause was a fall, and paralysis appeared from six to 48 hours after injury in most patients. Ten patients made some recovery after late reduction but three remained totally paralysed. We discuss the pathogenesis of the late cord lesion and the reasons for delay in diagnosis.
Primary skin closure after the surgical correction of severe club-foot may be difficult. We describe the use of a tissue expander to provide sufficient skin, and review some aspects of the use of the method.
