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Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_30 | Pages 47 - 47
1 Aug 2013
Siddiqui M Bidaye A Baird E Jones B Stark A Abu-Rajab R Anthony I Ingram R
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We compared the postoperative wound discharge rates and 3 months clinical results of three types of wound closure and dressing – 2-octylcyanoacrylate with Opstie (G+O), 2-octylcyanoacrylate with Tegaderm (G+T), and Opsite without 2-octylcyanoacrylate (O) in patients having primary total hip arthroplasty.

We randomised 141 patients scheduled for primary total hip arthroplasty into 3 arms of this study- G+O, G+T, or O. The extent of wound discharge was recorded on a diagrammatic representation of the dressing in situ on paper and graded each day. Dressings were left in-situ provided the extent of wound discharge allowed for this. The patient was clinically reviewed at 3 months to assess their scar length, cosmesis, scar discomfort, and evidence of superficial or deep wound sepsis.

A greater number of patients dressings remained dry on day 1 postoperatively in the two groups with 2-octylcyanoacrylate compared to the no glue group p=0.001. G+T group had a significantly lower proportion of patients with increased leakage of wounds on 2nd postoperative day p=0.044. At 3 months review, there was no statistical difference in the Hollander score or scar discomfort.

In patients who have had primary total hip arthroplasty, usage of 2-octylcyanoacrylate for wound closure along with Tegaderm dressing reduces wound discharge. The same effect is not noted in glue with Opsite group. Whilst dressing changes required in the non-glue group compared from the two glue groups did not reach statistical significance, this may have clinical relevance for patients and nursing staff. No effect on postoperative length of stay, or wound complications was noted.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_28 | Pages 69 - 69
1 Aug 2013
Smith J Blyth M Jones B MacLean A Rowe P
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Total knee arthroplasty (TKA) has been established as a successful procedure for relieving pain and improving function in patients suffering from severe knee osteoarthritis for several decades now. It involves removing bone from both the medial and lateral compartments of the knee and sacrificing one or both of the cruciate ligaments. This in turn is likely to have an impact on the patients' functional outcome. In subjects where only one compartment of the knee joint is affected with osteoarthritis then unicondylar knee arthroplasty (UKA) has been proposed as an alternative procedure to TKA. This operation preserves the cruciate ligaments and removes bone only from the affected side of the joint. As a result there is the possibility of an improved functional outcome post surgery. UKA has been associated with faster recovery, good functional outcome in terms of range of motion and it is bone sparing compared to TKA. However, the biggest obstacle to UKA success is the high failure rates.

The aim of this study was to compare the functional outcome of computer navigated TKA (n=60) and UKA (n=42) patients 12 month post operation using flexible electrogoniometry. Flexible electrogoniometry was used to investigate knee joint kinematics during gait, slopes walking, stair negotiation, and when using standard and low chairs. Maximum, minimum and excursion knee joint angles were calculated for each task.

The biomechanical assessment showed statistically significant improvements in the knee kinematics in terms of maximum (p<0.0004) and excursion (p<0.026) knee joint angles in the UKA patient group compared to the navigated TKA group for each of the functional tasks. There was no statistically significant difference between the minimum knee joint angles during these functional tasks (p>0.05).

Therefore, UKA patients were showed to have a significantly better functional outcome in terms of the maximum knee joint angle during daily tasks. A limitation of this study is that it compares two cohorts rather than two randomised groups. It is expected that UKA patients will have a better functional outcome. Our results suggest that for patients with less severe knee osteoarthritis, UKA may offer a better functional outcome than the more common surgical option of TKA. The recent advancements in computer assisted and robotic assisted knee arthroplasty has the possibility to improve the accuracy of UKA and therefore led to the increase in confidence and in usage in a procedure which has the potential to give patients a superior functional outcome.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_30 | Pages 16 - 16
1 Aug 2013
Kumar S O'Neill G Stark A Jones B McCartney P Wells J Ingram R
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The aim of this study was to characterise noise associated with ceramic-on-ceramic total hip arthroplasty (THA).

A questionnaire was constructed to assess noise associated with THA. 116 patients responded. All had ceramic-on-ceramic hybrid THA at Glasgow Royal Infirmary between 2005 and 2007 using a Trident prosthesis and Exeter stem. Oxford Hip Questionnaires (OHS) were also completed by the patients.

16.4% of respondents reported noise associated with their ceramic hip. The vast majority reported onset at least 1 year after implantation. The most common noise types were ‘clicking’ (47%) or ‘grinding’ (42%), while ‘squeaking’ was least frequently reported (11%). Noise was most commonly brought on by bending and during sit to stand movements.

No correlation was identified between the incidence of noise and any patient specific factor or demographic variable. The mean OHS at questionnaire follow-up was 39 and there was no significant difference in OHS when comparing noisy and silent hips (p=0.65). Only 1 patient limited social or recreational activities and overall patients felt the noise had minimal effect on their quality of life.

Acetabular component inclination angles were compared on post-operative x-rays. There was no significant difference (p=0.51) in inclination angles of the noisy (47.1°±6.3°, range 30–57°) and silent hips (47.8°±6.1°, range 35–68°). The groups were further analysed for deviation out with the desirable inclination range of 40–45°. Of the noisy hips, a total of 73% were out with this range compared to 63% in the silent hip group.

The incidence of noise within this ceramic-on-ceramic THA group did not appear to be related to patient specific factors, patient reported outcome (OHS) or acetabular inclination angles. Subjective appraisal of the noise revealed that ‘squeaking’ was not common but patients tended to report ‘clicking’ and ‘grinding’ more. The precipitation of noise with bending activities reinforces a possible mechanical cause.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_31 | Pages 39 - 39
1 Aug 2013
Lavery J Anthony I Blyth M Jones B
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To validate the Modified Forgotten Joint Score (MFJS) as a new patient-reported outcome measure (PROM) in hip and knee arthroplasty against the UK's gold standard Oxford Hip and Knee Scores (OHS/OKS).

The original Forgotten Joint Score was created by Behrend et al to assess post-op hip/knee arthroplasty patients. It is a new assessment tool devised to provide a greater discriminatory power, particularly in the well performing patients. It measures an appealing concept; the ability of a patient to forget about their artificial joint in everyday life. The original FJS was a 12-item questionnaire, which we have modified to 10-items to improve reliability and missing data.

Postal questionnaires were sent out to 400 total hip/knee replacement (THR/TKR) patients who were 1–2 years post-op, along with the OHS/OKS and a visual pain analog score. The data collected from the 212 returned questionnaires (53% return rate) was analysed in relation to construct and content validity. A sub-cohort of 77 patients took part in a test-retest repeatability study to assess reliability of the MFJS.

The MFJS proved to have an increased discriminatory power in high-performing patients in comparison to the OHS and OKS, highlighted by its more normal frequency of distribution and reduced ceiling effects in the MFJS. 30.8% of patients (n=131) scored 42–48 (equivalent to 87.5–100 in the MFJS) or more in the OKS compared to just 7.69% in the MFJS TKR patients. The MFJS proved to have an increased test-retest repeatability based upon its intra-class correlation coefficient of 0.968 compared to the Oxford's 0.845.

The MFJS provides a more sensitive tool in the assessment of well performing hip and knee arthroplasties in comparison to the OHS/OKS. The MFJS tests the concept of awareness of a prosthetic joint, rather than pain and function and therefore should be used as adjunct to the OKS/OHS.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_30 | Pages 17 - 17
1 Aug 2013
Boyle J Anthony I Jones B MacLean A Wheelwright E Blyth M
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A retrospective analysis was carried out to determine the influence of pre-existing spinal pathology on the outcome of Total Knee Replacement surgery. Data was collected from 345 patients who had undergone Total Knee Replacement, at four centres in the UK, between 2000 and 2007. Oxford Knee Scores (OKS), American Knee Society Scores (AKSS) and SF-12 questionnaires were recorded prospectively. Data was collected pre-operatively and then post-operatively at 3 months, 1 year and 2 years. Patients were divided into those with (n=40) and without a history of low back pain (n=305). In addition to determining the influence of low back pain on outcome after Total Knee Replacement we also examined the influence of concomitant hip and ankle pathology in the same cohort of patients.

OKS scores were significantly worse for patients with symptomatic low back pain at 3 (p=0.05), 12 (p=0.009) and 24 months (p=0.039) following surgery. SF-12 physical scores followed a comparable pattern with significance demonstrated at 3 (p=0.038), 12 (p=0.0002) and 24 months (p=0.016). AKSS followed a similar pattern, but significance was only reached at 1 year (p=0.013). The mental component of the SF-12 measure demonstrated a significant improvement in patients' mental health post-operatively for patients with no history of low back pain. In contrast patients with low back pain showed no improvement in mental health scores post-operatively.

In contrast to low back pain, hip and ankle pathology had no statistically significant detrimental effect on the outcome of Total Knee Replacement surgery.

This study demonstrates that low back pain significantly affects the functional outcome after Total Knee Replacement surgery and that patients with low back pain show no improvement in mental health post-operatively.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_30 | Pages 55 - 55
1 Aug 2013
Sciberras N Murphy E Jones B Blyth M
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Deep surgical infections are a serious complication of total knee arthroplasty (TKA). Various protocols exist for treating these infections, each with its own advocates. In this series we report the one to five year follow-up of infected TKA that were treated with a two-stage revision knee replacement at the Glasgow Royal Infirmary between December 2003 and March 2009.

48 patients were identified from the hospital database. 6 of these were excluded as they did not meet the stipulated infection criteria. Another patient was excluded as no notes were available thereby the infection status could not be determined. Another 8 patients were excluded as these only had a first stage.

33 patients (16 male) average age 67y (49–88) met the inclusion criteria. Mean BMI was of 31.62 (19–47) and 8 patients suffered from rheumatoid arthritis. At presentation, the median for the ESR, CRP and WCC were 70.5, 133 and 8.5 respectively. The infective organism was identified in 22 patients. Following the first stage, the patients were treated with antibiotics (initially intravenous followed by oral) for an average of 11.8 weeks (4–52 weeks). This procedure failed to eliminate the infection in 6 patients (18.18%) who had further re-admissions for infection of the affected prosthesis. The resultant success rate is of over 80% which is comparable to literature data (success rates of 41% to 96% quoted). For these patients, the average time to review was 25.13 months (12–67months). At review these patients had a mean extension of 2.17° (0–10°) and a mean flexion of 98.26 (70–120°). These patients were all satisfied with their outcome.

Our results show a high successful rate of elimination of infection when a two-stage revision is used for infected knee prosthesis with over 80% of patients free of infection.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_28 | Pages 91 - 91
1 Aug 2013
Motesharei A Rowe P Smith J Blyth M Jones B MacLean A
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Unicompartmental knee arthroplasty (UKA) has been gaining popularity in recent years due to its perceived benefits over total knee replacements, such as greater bone preservation, reduced operating-room time, better postoperative range of motion and improved gait. However there have been failures associated with UKA caused by misalignment of the implants.

To improve the implant alignment a robotic guidance system called the RIO Robotic Arm has been developed by MAKO Surgical Corp (Ft. Lauderdale, FL). This robotic system provides real-time tactile feedback to the surgeon during bone cutting, designed to give improved accuracy compared to traditional UKA using cutting jigs and other manual instrumentation.

The University of Strathclyde in association with Glasgow Royal Infirmary has undertaken the first independent Randomised Control Trial (RCT) of the MAKO system against the Oxford UKA – a conventional UKA used in the UK. The trial involves 139 patients across the two groups.

At present the outcomes have been evaluated for 30 patients. 14 have received the MAKO unicompartmental knee arthroplasty and 16 the Oxford UKA. Both groups were seen 1 year post-operatively. Kinematic data was collected while subjects completed level walking using a Vicon Nexus motion analysis system. Three-dimensional hip, knee and ankle angles were compared between the two arthroplasty groups.

Our initial findings indicate that hip and ankle angles show no significant statistical difference, however there is a significant difference (p < 0.05) in the knee angles during the stance phase of gait. Data shows higher angles achieved by the MAKO group over the Oxford.

It would appear from our early findings that the MAKO RIO procedure with Restoris implants gives at least comparable functional outcome with the conventional Oxford system and may prove once our full sample is available for analysis to produce better stance phase kinematics with a more active gait pattern than the conventional Oxford procedure.

Further work includes analysing the data obtained from the patients in a number of other activities. These include a full biomechanical analysis of ascending and descending a flight of stairs, sit to stand and a deep knee lunge. The high demand/high flexion tasks in particular may reveal if there's an advantage to using the MAKO procedure over the Oxford. If there is a direct correlation between alignment and patient function then this effect could be more significant in the more demanding patient tasks.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_25 | Pages 11 - 11
1 May 2013
Donaldson D Torkington M Anthony I Blyth M Jones B
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The longitudinal midline and medial-parapatellar incision are commonly used in Total Knee Arthroplasty (TKA). Medial-parapatellar incision n offers a smaller wound, avoids creation of thin skin flaps and easier exposure in obese patients. This incision creates a lateral skin flap which may be subject to poor blood supply and delayed wound healing.

We undertook a Randomised Controlled Trial (n=20) comparing midline and medial-parapatellar incisions. Cutaneous blood-flow was measured using a Doppler Imager. Interstitial fluid measurements for lactate, pyruvate, lactate/pyruvate ratio and glucose were obtained from subcutaneous microdialysis catheters. Wound cosmesis was graded and skin sensation tested.

Immediately post-op there was no significant difference in subcutaneous blood flow, but by day 3 patients with medial-parapatellar incisions showed greater bloodflow than midline incisions, particularly on the medial side (387 vs 278units p=0.148). At both day 1 and 3 post-op the lateral flap of the medial parapatellar incision showed decreased blood flow compared to the medial side, though these failed to reach significance. In contrast the midline incision showed no discernable difference in blood flow between the medial and lateral flaps. Concentrations of subcutaneous glucose increased from 4 hours post-op in the midline group, returning to baseline by 24hours. In contrast, the parapatellar group remained at base line throughout. Lactate concentrations increased over time in both groups peaking at 12hours post-op. No difference was noted between incision types with regard to wound cosmesis.

We conclude that the use of a medial-parapatellar incision results in only minimal biochemical changes, which are unlikely to alter wound healing. Medial-parapatellar incision is therefore a safe alternative to a midline incision and can be utilised in appropriate complex cases to aid surgical exposure.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_1 | Pages 164 - 164
1 Jan 2013
Bailey O Torkinton M Anthony I Wells J Jones B
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Introduction

Acute renal dysfunction (ARD) following orthopaedic surgery is known to increase morbidity, mortality, and length of hospital stay. The aim of this study was to compare the incidence of new acute post-operative renal dysfunction between two cohorts of elective orthopaedic surgical patients receiving either cefuroxime or a combination of gentamicin and flucloxacillin as prophylactic antibiotic regimes. The study was initiated following a change in antibiotic prophylaxis within our unit from cefuroxime to gentamicin and flucloxacillin.

Method

Using a standardised data collection tool we retrospectively reviewed medical records of 238 patients who had received 1.5g of cefuroxime (TKR: n = 128; THR: n=110). This data was compared to prospectively collected data from 254 patients (TKR=117 THR=137) who had received Flucloxacillin 2g and Gentamicin (with the dose based on height). Primary outcome measure for the study was the RIFLE criteria which grades renal impairment: 0-Nil, 1-Risk, 2-Injury, 3-Renal failure.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_1 | Pages 70 - 70
1 Jan 2013
Blyth M Smith J Jones B Rowe P
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This RCT compared electromagnetic (EM) navigated and conventional total knee arthroplasty (TKA) in terms of clinical and functional outcomes. 200 patients (navigated=102, conventional=98) were recruited. Oxford Knee Scores (OKS) and the American Knee Society Score (AKSS) were recorded pre operation, 3 and 12 months after surgery. Post operative (coronal, sagittal and rotational) alignment was analysed from 3D CT scans taken 3 months after surgery. An objective functional assessment was completed using electrogoniometry on a sub group (navigated=60, conventional=57) at 12 months post surgery.

The EM group showed statistically significantly improved OKS (p=0.04) and AKSS (p=0.03) scores at 3 months post operation. However at 12 months post surgery there was no difference between the two groups. At the 1 year follow up it was reported that 9% of the navigated compared to 14% of the conventional group were dissatisfied with their surgical outcome.

The mechanical axis alignment of 90% of the navigated group was within 3 degrees of neutral compared to 84% of the conventional group. Although all alignment parameters except for tibial rotation was improved in the navigated group they did not reach significance apart from femoral slope alignment (p=0.01).

There was no statistically difference between the surgical groups in terms of the maximum, minimum and excursion knee joint angles during 12 functional activities. Only the knee kinematic function cycles for level walking resulted in statistically significant higher knee joint angles during 55–70% of the gait cycle in the navigated group.

Knee alignment was better restored following EM navigated TKA relative to conventional TKA, but the difference was not significant. The EM group showed greater clinical and functional improvements at early follow-up; however this difference was not sustained at 12 months. The EM group reported minimal gait improvements. Proving cost-effectiveness for navigation systems in TKA remains a challenge.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_1 | Pages 32 - 32
1 Jan 2013
Boyle J Anthony I Jones B Wheelwright E Blyth M
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A retrospective analysis was carried out to determine the influence of pre-existing spinal pathology on the outcome of Total Knee Replacement surgery. Data was collected from 345 patients who had undergone Total Knee Replacement, at four centres in the UK, between 2000 and 2007. Oxford Knee Scores (OKS), American Knee Society Scores (AKSS) and SF-12 questionnaires were recorded prospectively. Data was collected pre-operatively and then post-operatively at 3 months, 1 year and 2 years. Patients were divided into those with (n=40) and without a history of low back pain (n=305). In addition to determining the influence of low back pain on outcome after Total Knee Replacement we also examined the influence of concomitant hip and ankle pathology in the same cohort of patients.

OKS scores were significantly worse for patients with symptomatic low back pain at 3 (p=0.05), 12 (p=0.009) and 24 months (p=0.039) following surgery. SF-12 physical scores followed a comparable pattern with significance demonstrated at 3 (p=0.038), 12 (p=0.0002) and 24 months (p=0.016). AKSS followed a similar pattern, but significance was only reached at 1 year (p=0.013). The mental component of the SF-12 measure demonstrated a significant improvement in patients' mental health post-operatively for patients with no history of low back pain. In contrast patients with low back pain showed no improvement in mental health scores post-operatively.

In contrast to low back pain, hip and ankle pathology had no statistically significant detrimental effect on the outcome of Total Knee Replacement surgery.

This study demonstrates that low back pain significantly affects the functional outcome after Total Knee Replacement surgery and that patients with low back pain show no improvement in mental health post-operatively.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XLIV | Pages 19 - 19
1 Oct 2012
Smith J Rowe P Blyth M Jones B
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The aim of this study was to determine the influence of electromagnetic (EM) navigation in total knee arthroplasty (TKA) on post operative function.

In this double blinded randomised control trial, patients with osteoarthritis either received TKA using conventional techniques (n = 49) or EM navigation (iNav Portable Navigation System, Zimmer Orthopaedics) (n = 52). All of the patients were reviewed in the Outcomes Clinic at 3 and 12 months. At 12 months post operation the patients completed an objective biomechanical functional assessment using flexible electrogoniometers, which recorded dynamic knee kinematics during daily activities. Knee joint flexion and extension moments were recorded at the 12 month post operation assessment. The functional assessment included validated questionnaires (Oxford Knee Score, American Knee Society Score, WOMAC Score and Short Form SF-36 Score). All patients underwent CT scanning of the implanted prosthesis to assess component alignment.

Improved alignment was recorded in the navigated group. However there was no significantly significant difference between the two surgical groups in terms of the subjective questionnaire scores. The biomechanical assessment showed no statistically significant differences in the maximum, minimum or excursion knee joint angles between the two surgical groups during the 12 daily functional tasks. However, significant differences were reported in level and slope walking activities during pre-swing phase (at around 60% of the gait cycle). The navigated group had significantly higher knee joint angles during pre swing suggesting a more vigorous push off into swing phase and a more ‘normal’ gait cycle. The two surgical groups were sub divided into males and females for the strength test. The female navigated group recorded a significantly greater hamstring (p = 0.03) and quadriceps (p = 0.003) moment. There was no significant difference in hamstring or quadriceps moments between the navigated and conventional male groups.

The knee kinematics and moment data suggests that the navigated group had an improved functional outcome. However the difference in the post-operation function of the two groups remains minimal despite the better alignment achieved using navigation.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXVII | Pages 499 - 499
1 Sep 2012
Bell S Young P Drury C Blyth M Jones B Mclean A
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Introduction

Total knee arthroplasty is an established and successful operation. In up to 10% of patients who undergo total knee arthroplasty continue to complain of pain [1]. Recently computerised tomography (CT) has been used to assess the rotational profile of both the tibial and femoral components in painful total knee arthroplasty.

Methods

We reviewed 56 painful total knee replacements and compared these to 59 pain free total knee replacements. Datum gathered from case notes and radiographs using a prospective orthopaedic database to identify patients. The age, sex, preoperative Oxford score and BMI, postoperative Oxford score and treatments recorded. The CT information recorded was limb alignment, tibial component rotation, femoral component rotation and combined rotation.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXIX | Pages 80 - 80
1 Sep 2012
Russell D Fogg Q Mitchell C Jones B
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Introduction

The superficial anterior vasculature of the knee is variably described; most of our information comes from anatomical literature. Descriptions commonly emphasise medial-dominant genicular branches of the popliteal artery. Quantifying the relative contribution of medial and lateral vessels to the anastomotic network of the anterior knee may help provide grounds for selecting one of a number of popular incisions for arthrotomy.

Aim

To describe the relative contribution of vessels to anastomoses supplying the anterior knee.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXVII | Pages 44 - 44
1 Sep 2012
Blyth M Jones B Smith J Rowe P
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Electromagnetic navigation versus conventional Total Knee Arthroplasty: Clinical improvements Optical and electromagnetic (EM) tracking systems are widely used commercially. However in orthopaedic applications optical systems dominate the market. Optical systems suffer from deficiencies due to line of sight. EM trackers are smaller but are affected by metal. The accuracy of the two tracker systems has been seen to be comparable1. Recent advancements in optical navigated TKA have shown improved overall limb alignment, implant placement and reduce outliers when compared to conventional TKA2-4.

This study is the first RCT to compare EM and conventional TKA. Two groups of 100 patients underwent TKA using either the EM navigation system or the conventional method. Frontal, sagittal and rotational alignment was analysed from a CT scan. Clinical scores including Oxford Knee Score (OKS) and Knee/Function American Knee Society Score (AKSS) were recorded pre-op, and at 3 and 12 months post-op. 3 month data presented includes 180 patients (n = 90). The 12 months data presented includes 140 (n = 70).

The two groups had similar mean mechanical axis alignments (EM 0.31o valgus, conventional 0.15o valgus). The mechanical axis alignment was improved in the EM group with 92% within +/-3o of neutral compared to 84% of the conventional group (p = 0.90). The alignment of the EM group was improved in terms of frontal femoral, frontal tibial, sagittal femoral, sagittal tibial and tibial rotation alignment. However, only the sagittal femoral alignment was significantly improved in the EM group (p = 0.04). Clinically, both TKA groups showed significant improvements in OKS and AKSS scores between both pre-op to 3 month post-op and 3 months to 12 months post-op (p<0.001). The OKS and the AKSS knee score for the EM group was significantly better at 3 months post-op (OXS p = 0.02, AKSS knee p = 0.04). However there was no difference between the groups at 12 months. The mean pre-op range of motion (ROM) for both groups was 105o. This decreased to 102o in the EM group and 99o in the conventional group at 3 months. There was a significant improvement at 12 months post-op, EM = 113o (p = 0.012) and conventional = 112o (p = 0.026). There was no significant difference in ROM between the two groups at 3 or 12 months post-op.

Therefore the alignment outcome of the EM TKA group was improved compared to the conventional group. The EM group also showed clinical improvements at 3 months post-op however these were not seen again at 12 months post-op. ROM was seen to decrease at 3 months post-op but then significantly improve by 12 month post-op.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXIX | Pages 44 - 44
1 Jul 2012
Blyth M Jones B Smith J Rowe P
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Recent advancements in optical navigated TKA have shown improved overall limb alignment, implant placement and reduced outliers compared to conventional TKA. This study represents the first RCT comparing EM navigation and conventional TKA. 3D alignment was analysed from CT scans. Clinical scores (Oxford Knee Score (OKS) and American Knee Society Score (AKSS)) were recorded at pre-op, 3 and 12 months post-op. Data presented includes 180 patients (n=90 per group) at 3 months and 140 (n=70 per group) at 12 months.

The groups had similar mean mechanical axis alignments (EM 0.31° valgus; conventional 0.15° valgus). Mechanical axis alignment however was improved in the EM group with 92% within +/−3° of neutral compared to 84% of the conventional group (p=0.90). The EM group showed improved coronal and sagittal femoral alignment and improved coronal, sagittal and rotational tibial alignment, which was significant for sagittal femoral alignment (p=0.04). The OKS and AKSS scores were significantly better for the EM group at 3 months post-op (OKS p=0.02, AKSS p=0.04), but there was no difference between groups at 12 months. The mean pre-op range of motion (ROM) for both groups was 105°. This decreased at 3 months to 102° in the EM group and 99° in the conventional group, but there was a significant improvement by 12 months: EM=113° (p=0.012) and conventional=112° (p=0.026). ROM was statistically similar between groups at all assessment phases.

Knee alignment was better restored following EM navigated TKA relative to conventional TKA, but the difference was not significant. The EM group showed greater clinical improvements at early follow-up; however this difference was not sustained at 12 months. ROM was seen to decrease at 3 months but then significantly improve by 12 month post-op. Proving cost-effectiveness for navigation systems in TKA remains a challenge.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXIII | Pages 9 - 9
1 Jul 2012
Russell D Fogg Q Mitchell CI Jones B
Full Access

The superficial anterior vasculature of the knee is variably described; most of our information comes from anatomical literature. Descriptions commonly emphasise medial-dominant genicular branches of the popliteal artery. Describing the relative contribution of medial and lateral vessels to the anastomotic network of the anterior knee may help provide grounds for selecting one of a number of popular incisions for arthrotomy.

The aim of this study is to describe the relative contribution of vessels to anastomoses supplying the anterior knee.

Cadaveric knees (n = 16) were used in two cohorts. The first cohort (n = 8) were injected at the popliteal artery with a single colour of latex, and then processed through a modified diaphanisation technique (chemical tissue clearance) before final dissection and analysis. This was repeated for the second cohort, but with initial dissection to identify potential source vessels at their origin. Each source vessel was injected with a different colour of latex. The dominant sources were determined in each specimen.

The majority of the specimens (n = 13; 81%) demonstrated that an intramuscular branch though the vastus medialis muscle was the dominant vessel. Anastomoses were most common over the medial side of the knee, both superiorly and inferiorly (3-5 anastomoses in all cases). Anastomosis over the lateral knee was infrequent (1 anastomosis in 1 specimen).

The results suggest that anterior vasculature of the knee is predominately medial in origin, but not from the genicular branches as previously described. This network of vessels found in the anterior knee is thought to be the main supply to the patella, extensor apparatus, anterior joint capsule and skin.

Optimum placement of incision for arthrotomy is a subject of debate. Considering the main blood supply to the anterior knee may help in choosing a particular approach.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXVIII | Pages 1 - 1
1 Jun 2012
Bell S Young P Drury C Jones B Blyth M MacLean A
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Total knee arthroplasty is an established and successful operation. In up to 13% of patients who undergo total knee arthroplasty continue to complain of pain. Recently computerised tomography (CT) has been used to assess the rotational profile of both the tibial and femoral components in painful total knee arthroplasty.

We reviewed 56 painful total knee replacements and compared these to 56 matched patients with pain free total knee replacements. Patients with infection, aseptic loosening, revision arthroplasties and gross coronal malalignment were excluded. Datum gathered from case notes and radiographs using a prospective orthopaedic database to identify patients. The age, sex, preoperative and postoperative Oxford scores, visual analogue scores and treatments recorded. The CT information recorded was limb alignment, tibial component rotation, femoral component rotation and combined rotation.

The two cohorts of patients had similar demographics. The mean limb alignments were 1.7 degrees varus and 0.01 degrees valgus in the painful and control groups respectively. A significant difference in tibial component rotation was identified between the groups with 3.2 degrees of internal rotation in the painful group compared to 0.5 degrees of external rotation in the control group (p=0.001). A significant difference in femoral component rotation was identified between the groups with 3.8 degrees of internal rotation in the painful group compared to 1.1 degrees of external rotation in the control group (p=0.001). A significant difference in the combined component rotation was identified between the groups with 6.8 degrees of internal rotation in the painful group compared to 1.7 degrees of external rotation in the control group (p=0.001).

We have identified significant internal rotation in a patient cohort with painful total knee arthroplasty when compared to a control group with internal rotation of the tibial component, femoral component and combined rotation. This is the largest comparison series currently in the literature.


The Journal of Bone & Joint Surgery British Volume
Vol. 93-B, Issue 4 | Pages 548 - 551
1 Apr 2011
Murphy E Spencer SJ Young D Jones B Blyth MJG

The objective of this study was to determine the effectiveness of screening and successful treatment of methicillin-resistant Staphylococcus aureus (MRSA) colonisation in elective orthopaedic patients on the subsequent risk of developing a surgical site infection (SSI) with MRSA.

We screened 5933 elective orthopaedic in-patients for MRSA at pre-operative assessment. Of these, 108 (1.8%) were colonised with MRSA and 90 subsequently underwent surgery. Despite effective eradication therapy, six of these (6.7%) had an SSI within one year of surgery. Among these infections, deep sepsis occurred in four cases (4.4%) and superficial infection in two (2.2%). The responsible organism in four of the six cases was MRSA. Further analysis showed that patients undergoing surgery for joint replacement of the lower limb were at significantly increased risk of an SSI if previously colonised with MRSA.

We conclude that previously MRSA-colonised patients undergoing elective surgery are at an increased risk of an SSI compared with other elective patients, and that this risk is significant for those undergoing joint replacement of the lower limb. Furthermore, when an infection occurs, it is likely to be due to MRSA.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_I | Pages 20 - 20
1 Mar 2010
Tornetta P Ricci W Russell T Jones B Petteys T Gerlach D
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Purpose: Many lateral malleolar fractures in patients with osteoporotic bone are rotationally unstable, requiring fixation stable in torsion with good fatigue properties, but without bulk due to the soft tissue constraints. The purpose of this study was to evaluate the torsional performance of a thin (1.5mm) plate with locked and non-locked constructs in a simulated osteoporotic lateral malleolus fracture.

Method: A transverse fracture gap to mimic comminution was created in (15 lb/ft3) density foam. 3 bicortical unlocked screws were used proximal to the fracture in a 5 hole thin (1.5mm) plate for both constructs. Distally, two screws that did not breach the far cortex (12mm) were placed as locked in one group and unlocked in the other. The constructs were loaded in torsion at 1 Hz at 7.5/0.75 in-lbf (0.85/0.08 N-m) of torque. A torsional fatigue failure was defined as either a fracture of the plate, screw pull-out, or construct rotation 10 degrees beyond the maximum initial rotational displacement. Testing was conducted until construct failure or run-out of 300,000 cycles.

Results: The thin plate constructs with locked distal screws showed significantly improved fatigue properties (p< 0.00001). None of the locking plate constructs failed prior to the 300,000 cycle end point. In stark contradistinction, all of the non-locked contructs failed at an average cycle count of only 9,541 (range 1,000 – 23,000 cycles). The failure mode for each of the non-locked constructs was pull-out of the distal screws.

Conclusion: These results indicate that the use of a thin plate with locking capability provides a significant advantage over non-locked constructs in fatigue performance in areas of poor bone density subjected to torsional loads, such as the lateral malleolus.