To examine the performance of film compared to DICOM (Digital Imaging and Communications in Medicine) images in the detection and volume appreciation of periprosthetic osteolysis around total knee replacements. Simulated osteolytic lesions were created around 3 cadaveric total knee replacements and fluoroscopic-assisted radiography as well as Computed Tomography derived imaging taken. Arthoplasty surgeons then reviewed the hard images (AP, Lateral, Paired Obliques and Computed Tomography) on 2 separate occasions regarding the presence and size of lesions. With a minimum of 2 months since the last assessment, DICOM images taken from the same knees were then assessed by the same 3 arthroplasty surgeons in the same manner using Syngo™ Pictured Archive Communication System on hospital computer monitors. Area under the ROC for lesions detection and kappa statistic for volume appreciation derived from the DICOM assessments were not superior with statistical significance to film assessments. Combinations of imaging that incorporated Paired Oblique views had superior performance in both hard-copy and DICOM imaging. Digital imaging in this study has not clearly demonstrated superiority to film images for detection and volume appreciation of periprosthetic osteolysis around total knee replacements. The value of the addition of the oblique view to routine assessment is again demonstrated.
This multicenter study compared computer-navigated TKA using either MIS or conventional surgical technique, using a CR fixed bearing knee, Stryker Navigation system and dedicated MIS instrumentation. It was hypothesized that patients would benefit from the MIS technique by shorter recovery periods, less blood loss, faster wound healing and improved mobility during early rehabilitation. A prospective multicentre double-blind controlled trial included 69 patients matched for age, gender, BMI (MIS n=36, CONV n=33). Assessments at pre-op, 1 week, 3 and 6 months post-op included surgery time, bloodloss, range of motion, Knee Society Score (KSS) and WOMAC, Chair rise test and quadriceps strength. Radiographic analysis included radiographs for lucencies and CAT scans for alignment, Four patients were lost to follow-up. The MIS group had significantly more prolonged surgery time and blood loss at 24 hours p<0.05. At 6 months mean flexion values for MIS (106,7°±12,91) and CONV 105,92 ±11,58) with no significant differences in flexion ROM between both groups at any time point. KSS scores showed a significant improvement (p<0,01) over time in both groups but no statistical significance between groups. WOMAC score also improved significantly (p<0,01) over time in both groups without reaching statistical significance. A significant decrease of anterior knee pain score was observed over time with no significant difference between both groups. Quadriceps strength recovery was not significant between groups but trended toward faster recovery in the MIS group. X-rays showed stable implants with no progressive radiolucent lines in all patients. The hypothesis that patients benefit from the MIS technique in the short term was not confirmed by the results of this study. The MIS surgery technique resulted in more blood loss intra-op and in the first 24hours post op as well as an elongated surgery time. The MIS surgery technique also failed to generate clear advantages in clinical or functional outcome that persisted over time.
Prophylactic pinning of the contralateral hip in the treatment of slipped upper femoral epiphysis (SUFE) has been shown to be safer than continued observation of the contralateral hip. This treatment remains controversial due to the potential for harm caused to an apparently unaffected hip. There is evidence that pinning of an already slipped epiphysis causes growth disturbance of the proximal femur, however this has been questioned in that the slip occurs at the hypertrophic layer of the growth plate with no damage to the germative layer. To determine whether prophylactic pinning affects subsequent growth of the unaffected hip in cases of unilateral SUFE.Introduction
Aim
Osteolysis commonly causes total knee replacement (TKR) failure, often associated with asymptomatic large defects. Detection and size estimation of lytic defects is important for the indications and planning of revision surgery. Our study compares the utility of fluoroscopic-guided plain X-rays and computed topography (CT) in osteolysis detection and volume appreciation. Three cadaveric specimens were imaged at baseline and following the creation of reamed defects (small, medium and large approximately = 1, 5 & 10 cm3 volume respectively) in the tibia and femur with TKR component implantation at each timepoint. Imaging was with fluoroscopic-guided plain X-rays (Anteroposterior & Lateral [APL], Paired Oblique [OBL]) as well as rapid-acquisition spiral Computed Topography [CT] with a beam-hardening artefact removal algorithm. Three arthroplasty surgeons estimated the size of the lesion, if present, and confidence (none=0, fair=1, excellent=2) in their assessment on randomly presented images. Each surgeon performed two assessments of each image one month apart. The accuracy of detecting lesions was determined using the area under the receiver-operating curve (AU-ROC) obtained from a logistic regression with adjustment for assessment sequence, observer, knee and bone. Volume appreciation and assessor confidence were determined using Kappa and the mean average of confidence scores respectively. The AU-ROC using combinations of either APL/OBL/CT (0.83) or OBL/CT (0.83) resulted in superior detection of lesions (p<0.05) compared to APL (0.75) or OBL alone (0.77). Correct volume appreciation was highest with APL/OBL/CT (kappa=0.52), followed by APL/OBL (0.51) and was superior (p<0.05) to APL (0.29) or CT alone (0.31). Small and medium defects were more often missed than large with all modalities (20.3 vs. 39.7 %). Femoral defects were missed more often than tibial defects (40% vs. 28.7%) and small lesions missed more with CT (50%) versus APL (48%) and Oblique (40%). CT missed 19% of large sized defects, attributed mostly to femoral (29.1%) rather than tibial defects (8.3%) Greater confidence was derived from use of CT (1.29) and APL (1.19) [Interquartile range (IQR) 1,2] when compared to OBL (.98, IQR 1,1) [p<.01]. Also, there was greater confidence regarding judgement of tibial defects (1.25, IQR 1,2) compared with femoral defects (1.05, IQR 1,1) [p<.01]. Combining all imaging modalities was synergistic and the most sensitive and specific means of defect detection and volume appreciation. CT provided more confidence, superior detection and volume appreciation when used in combination with APL/OBL versus APL/OBL alone. There is also additional value when APL is combined with OBL.
Tranexamic acid is a potent antifibrinolytic which has shown efficacy in reducing blood loss in total knee arthroplasty when administered intravenously. We performed a randomised controlled trial of oral tranexamic acid in total knee arthroplasty in order to assess the blood sparing effect of this preparation. We investigated the effects of oral tranexamic acid on blood loss in 50 patients (25 treatment arm and 25 placebo) undergoing unilateral total knee replacement in a two year period starting January 2007. The treatment arm received 1500 mg of encapsulated oral tranexamic acid TDS pre-operatively, with the third dose occurring within two hours of surgery, and a fourth dose six hours post surgery. The control arm received an identically encapsulated non-active formulation at the same dosing intervals. Baseline pre-operative haemoglobin and heamatocrit measures were collected. Outcome measures were post-operative haemoglobin and haematocrit taken 12 to 24 hours post operatively and total blood loss in wound drains at 24 hours. Results showed a non-clinically significant trend towards decreased blood loss and transfusion rates in the treatment arm when compared to placebo. No significant adverse events occurred in relation to the use of oral Tranexamic acid in this study. The perioperative use of oral tranexamic acid in conjuntion with elective total knee arthroplasty appears safe; however, its efficacy as a blood sparing medication is less than that which has been recorded with intravenous dosing. The study supports further consideration of the availability of intravenous tranexamic acid for decreasing blood loss in orthopaedic arthroplasty.
The five year results of 8187 primary total knee replacements undertaken for osteoarthritis in patients under the age of 55 years are presented. The casese were submitted to the Australian Orthopaedic Association National Joint Replacement Registry in the period 1st September 1999 to 31st December 2006. This represents 6.3% of the 130,377 primary knee replacements recorded by the registry for this period. The five year cumulative revision rate for patients under the age of 55 years was 8.0% (95% CI: 7.2 to 8.9). We compared the results to outcomes of older patients aged over 70 years at the time of surgery. The younger patients have a significantly higher risk of revision in the first five years (hazard ratio of 2.9; 95% CI= 2.59 to 3.26; p<
0.0001). Gender, mode of fixation, the use of cruciate retention or substitution prostheses or patella resurfacing did not significantly affect the rate of revision in those patients aged 55 years or less. Survival of fixed bearing implants was significantly better than that of mobile bearings. The most common reason for revision in this group was loosening (32.3%). Total knee replacement in patients under the age of 55 years is associated with a much higher risk of revision in the first five years. A decision to proceed with total knee replacement in this age group should be accompanied by a careful explanation of this significantly increased risk compared to knee replacement in older individuals.
Only the GMTJ of medial head was located as it usually has a lower attachment and is thicker. The soleus muscle has short multipennate fibres running obliquely between aponeuroses overlying its anterior and posterior surfaces. GM has long parallel fibres and merges distally with the posterior aponeurosis of the soleus muscle. The GMTJ has a unique conical appearance on ultrasound. Pre operative skin markings were compared with the location of GMTJ during surgery.
I routinely request MRI with contrast before bone graft surgery so that I can give the patient an idea of the likely success of that surgery beforehand.
This enforced restriction means that all my bone grafts now come from the distal radius. There is good evidence to support the use of graft from this site – especially in the younger male. As a result, I developed the technique of employing vascularised grafts for all my scaphoid non-unions. Not necessarily because I thought they were any better, but because they were straightforward to perform, offered no disadvantages, and may actually offer an advantage. I favour the palmar grafts described by Mathoulin because of the biomechanics of the humpback deformity. Scaphoid waist non unions need a palmar wedge to restore their length and shape. Using a corticocancellous palmar wedge graft from the distal radius provides this. Proximal pole non unions do demand a different approach (both surgically and in decision making). The Zaidemberg dorsal graft is usually more appropriate for these cases, but I recommend developing skills in both techniques to use the right graft for the right indication. I will illustrate the surgical and rehabilitation techniques I employ in some detail, and discuss the results of these treatments in my personal series.
I will illustrate and justify the salvage techniques I consider in scaphoid non union.
I will discuss a personal approach to managing this condition at each stage of presentation, considering how appropriate each alternative treatment may be, and describing in detail what happens to such patients in my practice.
As specialist hand surgeons, we pride ourselves on a diagnostic suspicion whenever we are met with an appropriate history or likely injury mechanism. We are able to assess the patient individually, their plain radiographs, MRI arthrograms and arthroscopic findings. The challenge in providing a service for this injury, is to extend that knowledge (or make it readily accessible) to a wider group of generalists in Orthopaedic Surgery, Trauma Surgery and Emergency Medicine. I will describe my method of assessment with preferred imaging techniques.
I will illustrate some of the pitfalls in decision making with a series of case examples, and explain my personal approach.
Acute repair Reconstruction Salvage I will describe my preferred techniques, which procedures I no longer perform (and why) and rehabilitation programmes in detail for these categories.
Squeaking is a rare complication of hard-on-hard hip bearings. Occasionally the noise is troublesome enough to warrant revision surgery. The purpose of this study is to contribute to the understanding of the mechanism(s) underlying squeaking. We analyzed 10 alumina ceramic-on-ceramic bearings from squeaking hips collected at revision surgery. The reason for revision was given as squeaking (6 cases) or squeaking and pain (4 cases). Six of the 10 patients were male, average patient age was 48. Bearings were retrieved after an average of 23 months in service (11 to 61 months). There were 4 different designs of acetabular component from 2 different manufacturers. Nine have an elevated metal rim which is proud of the ceramic and one does not. Two bearings were 36mm in diameter, 6 were 32mm and 2 were 28mm. All 10 bearings showed evidence of edge loading wear. Mean dimensions of the wear patch were 37mm by 12mm on the acetabular component and 32mm by 13mm on the femoral heads. Wear dimension was not related to bearing diameter. Seven of the 10 implants also had evidence of impingement of the femoral neck against the elevated metallic rim or the ceramic insert or both. There was no chipping or fracture of any of the ceramic components. Squeaking is a recently recognized complication of hard on hard bearing surface. This retrieval study is the first of its kind, to our knowledge attempting to unravel the mechanism of this undesirable complication. Although impingement seems to be present in majority of cases, the latter does not seem to be necessary. Edge loading wear was the common factor in all cases and this may prove to be a critical mechanism.
As part of a user group of a collarless polished tapered stem a database was established in 1993 recording all significant data pre-operatively, intra-operatively and at 1,3,5 and 7 years. All were primary hip replacements and the study included 38 different surgeons who were free to use the head size, approach and cup of their choosing. All hips had a collarless polished tapered prosthesis (Zimmer inc.). Data on 2,250 hips were available for analysis and stratification of risk factors for dislocation. Correlation of head size and surgical approach was performed and tested for significance. The patient demographics were standard for a typical arthroplasty study group. Of the surgical approaches used, 13.1% were anterolateral, 27.55% lateral, 23.88% posterior and 35.47% Hardinge. There were no trochanter osteotomies or anterior approaches. 94 (100%) of the hips had a first dislocation occurring in the first two years: 38 during acute stay (40.43%), 45 from acute stay to the first year (47.88%) and 11 during the second year (11.7%). The 22mm head was associated with the greatest risk of dislocation (5.93%, P <
0.001). The risks with the 28mm head (3.05%) and the 26mm head (2.5%) were not significantly different. The lowest risk of dislocation occurred with the lateral approach (2.11%) and the highest with the posterior approach (5.99%). Dislocation rates for the anterolateral and Hardinge approaches (4.1% and 3.28% respectively) were not significantly different. Unfortunately data pertaining to frequency of capsular repair combined with the posterior approach was not available. The combination of lateral approach and 28mm head was associated with the lowest dislocation risk of 1.56%, while the risk with the posterior approach and 22mm head was the highest at 10.09%.
We report a case of Perthes like changes in the rare disorder of Geleophysic dysplasia and add it to the world literature (24 cases). We found an increased incidence of Perthes at 12% (3/25). Geleophysic dysplasia is characterised by short stature with short limbs distally, normal intelligence, joint stiffness, hepatomegaly and happy facial characteristics. The disease has the clinical and histological appearance of a mucopolysaccharidosis. Perthes changes were seen at the age of 4 years and treated conservatively, with poor clinical results despite the early onset and reasonable radiological improvement. MRI scans of the affected hip did not show any unusual features that differentiate it from normal Perthes disease. The patient also developed carpal tunnel syndrome, which has been seen in with increasing frequency in mucopolysaccharidoses such as Hurlers syndrome, but has not been associated with Geleophysic dysplasia before.
The effect of screw geometry on the pullout strength of Anterior Cruciate Ligament [ACL] reconstruction is well documented. Most research has looked at the effect of screw length and diameter, however other factors such as the degree of taper may also be important. Tapered screws should in theory be associated with increased pullout strength. This has not been demonstrated either clinically or A parallel and tapered screw were manufactured which were identical in all other respects. Sixty superficial digital flexors from the hind legs of sheep were harvested. The tendons were paired and combined to form a quadruple tendon reconstruction of approximately 7mm diameter as measured with graft sizer. An ACL reconstruction was performed on the proximal tibia of 30 bovine knees, which had been harvested in right and left knee pairs, using the quadruple tendon. Fifteen reconstructions were fixed using tapered screws and fifteen with non-tapered screws. The insertion torque of both tapered and non tapered screws were recorded using an instrumented torque screwdriver. The reconstructions were mounted in an Instron materials testing machine with an x-ray bearing system to eliminate horizontal forces, to ensure that the forces were all directed along the line of the tibial tunnel. The maximum pullout strengths were recorded in each case. Five knee pairs were subjected to bone densitometry scanning to ensure that any difference in pull out strength was not due to changes in bone density between right and left knee pairs. Results indicated that there was no difference between right and left knee pairs [p = 0.58] and that tapered screws were associated with significantly higher pull-out strengths [p=0.007] and insertion torques [p = 0.001].
This study reports the outcome of using the Posterior Lip Augmentation Device (PLAD) for recurrent dislocation of total hip replacement. Twenty-seven patients (16 in Inverness, 11 in Leeds) were treated with the device. The indication for its use was recurrent dislocation of the hip in a patient who had a well-orientated and well-fixed cemented acetabular component. The patients had had between 2 and 14 dislocations before using the PLAD. 24 of the 27 patients had satisfactory control of the dislocations after surgery. The operation was found to be straightforward in most cases with few complications, although one case in the Inverness series has a partial sciatic nerve palsy which is recovering. Of the three failures, two had recurrent dislocation after the use of the PLAD. In one of these, in whom the dislocation followed acetabular reconstruction with impaction grafting, the cup also pulled out due to the semi-captive state after use of the PLAD. Both of these cases were treated by a Girdlestone excision arthroplasty. There was one final failure in whom there has been no further dislocation but following an abduction injury some four months after surgery, progressive cup loosening developed and he awaits revision of the cup. One patient complains of an occasional click in the hip joint and a broken screw is visible on x-ray but there has been no loss of position of the device and no further evidence of dislocation. Overall, we have found that this device gives satisfactory control of recurrent dislocations of the hip but the failures have stressed the need to ensure that the cup fixation is sound before inserting the device.