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Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_13 | Pages 62 - 62
7 Aug 2023
Khatri C Harrison C Scott C Clement N MacDonald D Metcalfe A Rodrigues J
Full Access

Abstract

Background

The Forgotten Joint Score (FJS) is a 12-item patient reported outcome measurement instrument. It was developed with classical test theory, without testing assumptions such as unidimensionality (all items reflect one underlying factor), appropriate weighting of each item, no differential item function (DIF, different groups answer the same way), and monotonicity (people with higher function have higher score). We applied item response theory (IRT) to improve the validity of FJS to contemporary standards to optimise it for ongoing use.

Research Questions

Does the FJS reflect one latent trait? Can an IRT model be fitted to the FJS to provide interval-scaled measurement?


Orthopaedic Proceedings
Vol. 104-B, Issue SUPP_7 | Pages 28 - 28
1 Jul 2022
Yapp L Scott C Macdonald D Howie C Simpson H Clement N
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Abstract

INTRODUCTION

This study investigates whether primary knee arthroplasty (KA) restores health-related quality of life (HRQoL) to levels expected in the general population.

METHODOLOGY

This retrospective case-control study utilises two sources: patients undergoing primary KA from a University Teaching hospital; and individual-level data from the Health Survey for England which was used to represent the General Population.

Propensity score matching was used to balance covariates (sex, age and body mass index (BMI)) and facilitate group comparisons. Two matched cohorts with 3029 patients each were obtained for the adjusted analyses (median age 70.3 interquartile range (IQR) 64–77; Female sex 3233 (53.4%); median BMI 29.7 IQR 26.5-33.7). HRQoL was measured using the three-level version of the EuroQol 5-Dimensions’ (EQ-5D-3L) Index and EQ-VAS scores.


Bone & Joint Open
Vol. 3, Issue 7 | Pages 573 - 581
1 Jul 2022
Clement ND Afzal I Peacock CJH MacDonald D Macpherson GJ Patton JT Asopa V Sochart DH Kader DF

Aims

The aims of this study were to assess mapping models to predict the three-level version of EuroQoL five-dimension utility index (EQ-5D-3L) from the Oxford Knee Score (OKS) and validate these before and after total knee arthroplasty (TKA).

Methods

A retrospective cohort of 5,857 patients was used to create the prediction models, and a second cohort of 721 patients from a different centre was used to validate the models, all of whom underwent TKA. Patient characteristics, BMI, OKS, and EQ-5D-3L were collected preoperatively and one year postoperatively. Generalized linear regression was used to formulate the prediction models.


Orthopaedic Proceedings
Vol. 104-B, Issue SUPP_6 | Pages 8 - 8
1 Jun 2022
Ross L O'Rourke S Toland G Harris Y MacDonald D Clement N Scott C
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This study aims to determine satisfaction rates after hip and knee arthroplasty in patients who did not initially respond to PROMs, characteristics of non-responders, and contact preferences to maximise response rates. We performed a prospective cohort study of 709 patients undergoing THA and 737 patients undergoing TKA in a single centre in 2018. EQ-5D health related quality of life score and Oxford Hip/knee scores (OHS/OKS) were completed preoperatively and at 1year postoperatively via post when satisfaction was also assessed. Univariate, multivariate and receiver operator curve analysis were performed.

151/709 (21.2%) hip patients were non-responders, 83 (55.0%) of whom were contactable. 108/737 (14.6%) knee patients were non-responders, 91 (84.3%) of whom were contactable. There was no difference in satisfaction after arthroplasty between initial non-responders and responders for hips (74/81 vs 476/516, p=0.847) or knees (81/93 vs 470/561, p=0.480). Initial and persistent non-response was associated with younger age, higher BMIs and significantly worse preoperative PROMS for both hip and knee patients (p=0.05). Multivariate analysis demonstrated that younger age, higher BMI and poorer pre-operative OHS were independently associated with persistent non-response to hip PROMs (p<0.05). For the entire cohort (n=1352) patients <67 years were less likely to respond to postal PROMs with OR 0.63 (0.558 to 0.711). Using a threshold of >66.4 years predicted a preference for contact by post with 65.4% sensitivity and 68.1% specificity (AUC 0.723 (0.647-0.799 95%CI, p<0.001)).

Most initial non-responders were ultimately contactable with effort. Satisfaction rates were not inferior in patients who did not initially respond to PROMs.


Bone & Joint Open
Vol. 3, Issue 2 | Pages 145 - 151
7 Feb 2022
Robinson PG Khan S MacDonald D Murray IR Macpherson GJ Clement ND

Aims

Golf is a popular pursuit among those requiring total hip arthroplasty (THA). The aim of this study was to determine if participating in golf is associated with greater functional outcomes, satisfaction, or improvement in quality of life (QoL) compared to non-golfers.

Methods

All patients undergoing primary THA over a one-year period at a single institution were included with one-year postoperative outcomes. Patients were retrospectively followed up to assess if they had been golfers at the time of their surgery. Multivariate linear regression analysis was performed to assess the independent association of preoperative golfing status on outcomes.


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_12 | Pages 11 - 11
1 Oct 2021
Turnbull G Nicholson J Marshall C Macdonald D Breusch S Clement N
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The Olympia femoral stem is a stainless steel, anatomically shaped, polished and three-dimensionally tapered implant designed for use in cemented total hip arthroplasty (THA). The primary aim of this study was to determine the long-term survivorship, radiographic outcome, and patient reported outcome measures (PROMs) of the Olympia stem.

Between May 2003 and December 2005, 239 patients (264 THAs) underwent a THA with an Olympia stem in our institution. PROMs were assessed using the Oxford Hip Score (OHS), EuroQol-5 dimensions (EQ-5D) score and patient satisfaction at mean 10-years following THA. Patient records and radiographs were then reviewed at a mean of 16.5 years (SD 0.7, 15.3 to 17.8) following THA to identify occurrence of complications or revision surgery for any cause.

Mean patient age at surgery was 68.0 years (SD 10.9, 31–93 years). There were 156 women (65%, 176 THAs). Osteoarthritis was the indication for THA in 204 patients (85%). Stem survivorship at 10 years was 99.2% (95 % confidence interval [CI], 97.9%-100%) and at 15 years was 97.5% (94.6%–100%). The 15-year stem survival for aseptic loosening was 100%. Only one occurrence of peri-prosthetic fracture was identified, with no episodes of dislocation found. At a mean of 10 (SD 0.8, 8.7 –11.3) years follow-up, mean OHS was 39 (SD 10.3, range 7 – 48) and 94% of patients reported being very satisfied or satisfied.

The Olympia stem demonstrated excellent 10-year PROMs, very high rates of stem survivorship and negligible peri-prosthetic fracture and dislocation rate at final follow-up beyond 15 years.


The Bone & Joint Journal
Vol. 103-B, Issue 7 | Pages 1254 - 1260
1 Jul 2021
Calabro L Clement ND MacDonald D Patton JT Howie CR Burnett R

Aims

The primary aim of this study was to assess whether non-fatal postoperative venous thromboembolism (VTE) within six months of surgery influences the knee-specific functional outcome (Oxford Knee Score (OKS)) one year after total knee arthroplasty (TKA). Secondary aims were to assess whether non-fatal postoperative VTE influences generic health and patient satisfaction at this time.

Methods

A study of 2,393 TKAs was performed in 2,393 patients. Patient demographics, comorbidities, OKS, EuroQol five-dimension score (EQ-5D), and Forgotten Joint Score (FJS) were collected preoperatively and one year postoperatively. Overall patient satisfaction with their TKA was assessed at one year. Patients with VTE within six months of surgery were identified retrospectively and compared with those without.


The Bone & Joint Journal
Vol. 103-B, Issue 5 | Pages 846 - 854
3 May 2021
Clement ND Scott CEH Hamilton DF MacDonald D Howie CR

Aims

The aim of this study was to identify the minimal clinically important difference (MCID), minimal important change (MIC), minimal detectable change (MDC), and patient-acceptable symptom state (PASS) threshold in the Forgotten Joint Score (FJS) according to patient satisfaction six months following total knee arthroplasty (TKA).

Methods

During a one-year period 484 patients underwent a primary TKA and completed preoperative and six-month FJS and OKS. At six months patients were asked, “How satisfied are you with your operated knee?” Their response was recorded as: very satisfied, satisfied, neutral, dissatisfied, or very dissatisfied. The difference between patients recording neutral (n = 44) and satisfied (n = 153) was used to define the MCID. MIC for a cohort was defined as the change in the FJS for those patients declaring their outcome as satisfied, whereas receiver operating characteristic curve analysis was used to determine the MIC for an individual and the PASS threshold. Distribution-based methodology was used to calculate the MDC.


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_7 | Pages 6 - 6
1 May 2021
Martinson ES Macdonald D Clement ND Howie CR
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Non-surgical osteoarthritis management includes analgesia escalation to oral opiates; however, tolerance can occur. This study aims to assess analgesic effects of opiate use pre-operatively and whether this influences outcome 1-year post-operatively in patients undergoing total hip/knee arthroplasty (THA/TKA).

This prospective study assessed 1487 patients undergoing primary THA (n=729) or TKA (n=758) for osteoarthritis, with 95 respectively reporting pre-operative opiate use >1 month. THA opiate users had significantly higher BMI (p=0.007) and more likely to suffer associated comorbidities. TKA opiate users were significantly younger (p<0.001), with higher BMI (p=0.019) and more likely to suffer associated comorbidities. Pre-operative quality of life (QoL) and joint specific function were significantly worse (Hip EQ-5D 0.17 vs 0.41, p<0.001, OHS 14.6 vs 21.2, p<0.001; Knee EQ-5D 0.27 vs 0.44, p<0.001, OKS 16.4 vs 21.4, p<0.001). Pre-operative pain was significantly worse in those taking opioids (Hip Pain VAS 42.73 vs 50.70, p<0.001; Knee Pain VAS 50.93 vs 53.36, p=0.30). Post-operatively the THA opiate group had significant improvement in EQ-5D (0.175, p<0.001) and OHS (6.5, p<0.001) but were significantly less improved than opiate naïve patients after adjusting for confounding (EQ-5D 0.10, p<0.001; OHS 3.2, p<0.001). TKA opiate group also had significant improvement in EQ-5D (p<0.001) and OKS (p<0.001) but were significantly less (EQ-5D 0.089, p<0.001; OKS 3.9, p<0.001) than opioid naïve patients.

Pre-operative opiate use was associated with significantly worse pre-operative QoL, joint specific function and worse subjective pain. Post-operatively, the opiate group had significantly lower improvement in their QoL and joint specific function.


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_4 | Pages 2 - 2
1 Mar 2020
MacKenzie S Carter T MacDonald D White T Duckworth A
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Whilst emergency fasciotomy for acute compartment syndrome (ACS) of the leg is limb and potentially lifesaving, there remains a perception that such surgery may result in excessive morbidity, which may deter surgeons in providing expeditious care. There are limited long-term studies reporting on the morbidity associated with fasciotomy.

A total of 559 patients with a tibial diaphyseal fracture were managed at our centre over a 7-year period (2009–2016). Of these patients, 41 (7.3%) underwent fasciotomies for the treatment of ACS. A matched cohort of 185 patients who did not develop ACS were used as controls. The primary short-term outcome measure was the development of any complication. The primary long-term outcome measure was the patient reported EQ-5D.

There was no significant difference between fasciotomy and non-fasciotomy groups in the overall rate of infection (17% vs 9.2% respectively; p=0.138), deep infection (4.9% vs 3.8%; p=0.668) or non-union (4.9% vs 7.0%; p=1.000). There were 11 (26.8%) patients who required skin grafting of fasciotomy wounds. There were 206 patients (21 ACS) with long-term outcome data at a mean of 5 years (1–9). There was no significant difference between groups in terms of the EQ-5D (p=0.81), Oxford Knee Score (p=0.239) or the Manchester-Oxford Foot Questionnaire (p=0.629). Patient satisfaction on a linear analogue scale was reduced in patients who developed ACS (77 vs 88; p=0.039).

These data suggest that when managed with urgent decompressive fasciotomies, ACS does not appear to have a significant impact on the long-term patient reported outcome, although overall patient satisfaction is reduced.


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_4 | Pages 4 - 4
1 Mar 2020
Al-Hourani K MacDonald D Breusch S Scott C
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Successful return to work (RTW) is a crucial outcome after primary total knee arthroplasty (TKA) in patients under 65 years old. We aimed to determine whether TKA facilitated RTW in patients <65 years, whose intention was to return preoperatively.

We prospectively assessed 106 TKA patients under 65 years over a 1 year period both preoperatively and at 1 year following surgery. Patient demographics were collected including Oxford knee score, Oxford-APQ, VAS pain/health scores and EQ-5D. A novel questionnaire was distributed to delineate pre-operative employment status and post-operative intentions. This included questions on nature of pre and post-operative occupation, whether joint disease affected their ability to work and details of retirement plans and how this was affected by their knee.

69 patients intended to return to work following their TKA. Following arthroplasty, 57/69 patients (82.6%) returned to work at a mean of 16.4 weeks (SD 16.6). Univariate analysis showed significant factors facilitating RTW included, pre-operative oxford knee score, pre-operative Oxford-APQ score and pre-operative EQ-5D score. These were not predictive on multivariate analysis.

This study finds that TKA facilitates return to work in 83% of those who intend to return to work following their surgery. This could have significant positive and health and financial cost implications for the individual, health system and society.


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_4 | Pages 5 - 5
1 Mar 2020
Nicholson J Clelland A MacDonald D Clement N Simpson H Robinson C
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To evaluate if clinical recovery following midshaft clavicle fracture is associated with nonunion and determine if this has superior predictive value compared to estimation at time of injury.

A prospective study of all patients (≥16 years) who sustained a displaced midshaft clavicle fracture was performed. We assessed patient demographics, injury factors, functional scores and radiographic predictors with a standardized protocol at six-weeks. Conditional-stepwise regression was used to assess which factors independently predicted nonunion at six-months post-injury determined by CT. The nonunion predictor six-week model (NUP6) was compared against a previously validated model based on factors available at time of injury (NUP0-smoking, comminution and fracture displacement).

200 patients completed follow-up at six months. The nonunion rate was 14% (27/200). Of the functional scores, the QuickDASH had the highest accuracy on receiver-operator-characteristic (ROC) curve analysis with a 39.8 threshold, above which was associated with nonunion (Area Under Curve (AUC) 76.8%, p<0.001).

On regression modelling QuickDASH ≥40 (p=0.001), no callus on radiograph (p=0.004) and fracture movement on examination (p=0.001) were significant predictors of nonunion. If none were present the predicted nonunion risk was 3%, found in 40% of the cohort (n=80/200). Conversely if two or more were present, found in 23.5% of the cohort, the predicted nonunion risk was 60%.

The NUP6 model appeared to have superior accuracy when compared to the NUP0 model on ROC curve analysis (AUC 87.3% vs 64.8% respectively).

Delayed assessment at six-weeks following displaced clavicle fracture enables a more accurate prediction of fracture healing.


The Bone & Joint Journal
Vol. 101-B, Issue 7 | Pages 860 - 866
1 Jul 2019
Nicholson JA Searle HKC MacDonald D McBirnie J

Aims

The aim of this study was to investigate the influence of age on the cost-effectiveness of arthroscopic rotator cuff repair.

Patients and Methods

A total of 112 patients were prospectively monitored for two years after arthroscopic rotator cuff repair using the Disabilities of the Arm, Shoulder and Hand questionnaire (DASH), the Oxford Shoulder Score (OSS), and the EuroQol five-dimension questionnaire (EQ-5D). Complications and use of healthcare resources were recorded. The incremental cost-effectiveness ratio (ICER) was used to express the cost per quality-adjusted life-year (QALY). Propensity score-matching was used to compare those aged below and above 65 years of age. Satisfaction was determined using the Net Promoter Score (NPS). Linear regression was used to identify variables that influenced the outcome at two years postoperatively.


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_7 | Pages 3 - 3
1 May 2019
MacDonald D Caba-Doussoux P Carnegie C Escriba I Forward D Graf M Johnstone A
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The aim of our study was to compare the incidence of post-operative anterior knee discomfort after anterograde tibial nailing by suprapatellar and infrapatellar approaches.

95 subjects presenting with a tibial fracture requiring an intramedullary nail were randomised to treatment using a suprapatellar (SP) or infrapatellar (IP) approach. Anterior knee discomfort was assessed at 4 months, 6 months and 1 year post operatively using the Aberdeen Weightbearing Test-Knee (AWT-K), knee specific patient reported outcome measures and the VAS pain score. The AWT-K is an objective measure which uses weight transmitted through the knee when kneeling as a surrogate for anterior knee discomfort.

53 patients were randomised to an SP approach and 42 to an IP approach. AWT-K results showed a greater mean proportion of weight transmitted through the injured leg compared to the uninjured leg when kneeling in the SP group compared to the IP group at all time points at all follow-up visits. This reached significance at 4 months for all time points except 30 seconds. It also reached significance at 6 months at 0 seconds and 1 year at 60 seconds.

We conclude that the SP approach for anterograde tibial nailing reduces anterior knee discomfort post operatively compared to the IP approach.


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_7 | Pages 6 - 6
1 May 2019
Scott C Clement N Yapp L MacDonald D Patton J Burnett R
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Anterior knee pain (AKP) is the commonest complication of total knee arthroplasty (TKA). This study aims to assess whether sagittal femoral component position is an independent predictor of AKP after cruciate retaining single radius TKA without primary patellofemoral resurfacing.

From a prospective cohort of 297 consecutive TKAs, 73 (25%) patients reported AKP and 89 (30%) reported no pain at 10 years. Patients were assessed pre-operatively and at 1, 5 and 10 years using the short form 12 and Oxford Knee Score (OKS). Variables assessed included demographic data, indication, reoperation, patella resurfacing, and radiographic criteria.

Patients with AKP (mean age 67.0 (38–82), 48 (66%) female) had mean Visual Analogue Scale (VAS) Pain scores of 34.3 (range 5–100). VAS scores were 0 in patients with no pain (mean age 66.5 (41–82), 60 (67%) female). Femoral component flexion (FCF), anterior femoral offset ratio, and medial proximal tibial angle all differed significantly between patients with AKP and no pain (p<0.001), p=0.007, p=0.009, respectively). All PROMs were worse in the AKP group at 10 years (p<0.05). OKSs were worse from 1 year (p<0.05). Multivariate analysis confirmed FCF and Insall ratio <0.8 as independent predictors of AKP (R2 = 0.263). Extension of ≥0.5° predicted AKP with 87% sensitivity.

AKP affects 25% of patients following single radius cruciate retaining TKA, resulting in inferior patient-reported outcome measures at 10 years. Sagittal plane positioning and alignment of the femoral component are important determinants of long-term AKP with femoral component extension being a major risk factor.


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_1 | Pages 11 - 11
1 Jan 2019
Clement ND Howard TA Immelman RJ MacDonald D Patton JT Lawson G Burnett R
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The primary aim of this study was to compare the knee specific functional outcome of partial compared with total knee replacement (TKR) for the management of patellofemoral osteoarthritis.

Fifty-four consecutive Avon patellofemoral replacements were identified and propensity score matched to a group of 54 patients undergoing a TKR with patella resurfacing for patellofemoral osteoarthritis. The Oxford knee score (OKS), the Short Form (SF-) 12 and patient satisfaction were collected (mean follow up 9.2 years). Survival was defined by revision or intention to revise.

There was no significant difference in the OKS (p>0.60) or SF-12 (p>0.28) between the groups. The TKR group was significantly less likely to be satisfied with their knee (95.1% versus 78.3%, OR 0.18, p=0.03). Length of stay was significantly (p=0.008) shorter for the Avon group (difference 1.8 days, 95% CI 0.4 to 3.2). The 10 year survival for the Avon group was 92.3% (95% CI 87.1 to 97.5) and for the TKR group was 100% (95% CI 93.8 to 100). There was no statistical difference in the survival rate (Log Rank p=0.10).

The Avon patellofemoral replacement have a shorter length of stay with a functional outcome and satisfaction rate that is equal to that of TKR. The benefits of the Avon need to be balanced against the increased rate of revision when compared with TKR.


The Bone & Joint Journal
Vol. 101-B, Issue 1 | Pages 41 - 46
1 Jan 2019
Clement ND Howard TA Immelman RJ MacDonald D Patton JT Lawson GM Burnett R

Aims

The primary aim of this study was to compare the knee-specific functional outcome of patellofemoral arthroplasty with total knee arthroplasty (TKA) in the management of patients with patellofemoral osteoarthritis.

Patients and Methods

A total of 54 consecutive Avon patellofemoral arthroplasties were identified and propensity-score-matched to a group of 54 patients undergoing a TKA with patellar resurfacing for patellofemoral osteoarthritis. The Oxford Knee Score (OKS), the 12-Item Short-Form Health Survey (SF-12), and patient satisfaction were collected at a mean follow up of 9.2 years (8 to 15). Survival was defined by revision or intention to revise.


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_1 | Pages 2 - 2
1 Jan 2019
Stirling P Goudie E MacDonald D Macpherson G Gaston P
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The optimal approach for total hip arthroplasty (THA) remains controversial. We present the results of the Direct Superior Approach (DSA), an improved variation of the posterior approach with high levels of stability, patient-reported functional outcomes, and satisfaction.

This is a single-surgeon prospective series. All patients undergoing THA between 2010 and 2015 via the DSA were included. Complication data was collected by interrogation of the Scottish Arthroplasty Project national joint registry. Pre and one-year post-operative Oxford Hip Score (OHS), Euroqol-5D (EQ-5D), and patient satisfaction questionnaires were collected.

659 patients received a THA via the DSA during the study period. Average age was 61.8 years (range 16.4–93.3). Analysis of registry data revealed no cases of dislocation, 5 cases of venous thromboembolism (0.75%), and 5 cases of deep infection (0.75%). 586 patients (88.9%) underwent their surgery in the National Health Service, and post-operative outcomes were available for 337 of these patients (57.5% follow-up) at one year. Average improvement in OHS and EQ-5D was 20 (range −14 – 48) and 0.39 (−0.697–1.2) respectively. 311 patients (92.3%) were satisfied.

This description of the DSA is accessible to all surgeons, confers excellent stability with no dislocations, and is associated with excellent post-operative functional outcomes and patient satisfaction.


Bone & Joint Research
Vol. 7, Issue 5 | Pages 351 - 356
1 May 2018
Yeoman TFM Clement ND Macdonald D Moran M

Objectives

The primary aim of this study was to assess the reproducibility of the recalled preoperative Oxford Hip Score (OHS) and Oxford Knee Score (OKS) one year following arthroplasty for a cohort of patients. The secondary aim was to assess the reliability of a patient’s recollection of their own preoperative OHS and OKS one year following surgery.

Methods

A total of 335 patients (mean age 72.5; 22 to 92; 53.7% female) undergoing total hip arthroplasty (n = 178) and total knee arthroplasty (n = 157) were prospectively assessed. Patients undergoing hip and knee arthroplasty completed an OHS or OKS, respectively, preoperatively and were asked to recall their preoperative condition while completing the same score one year after surgery.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_3 | Pages 2 - 2
1 Apr 2018
Hamilton D Loth F MacDonald D Giesinger K Patton J Simpson H Howie C Giesinger J
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Aim

To evaluate the association of BMI and improvement in patient-reported outcomes after TKA.

Methods

Knee replacement outcome data for procedures carried out over an eight month period was extracted from a regional arthroplasty register in the UK. Data was available before surgery and 12 months after. We analysed the impact of overweight on post-operative change in the Forgotten Joint Score − 12 (FJS-12) measuring joint awareness and the Oxford Knee Score (OKS) measuring pain and function using five BMI categories (A: <25, B: 25–29.9, C: 30–34.9, D: 35–39.9 and E: >40).


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_18 | Pages 1 - 1
1 Nov 2017
Bucknall V Rutherford D Macdonald D Shalaby H McKinley J Breusch S
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Patient reported outcomes and satisfaction scores following excision of interdigital Morton's neuroma have been recently established. However, little is known regarding what patient factors affect these outcomes. This is the first and largest prospective study to determine which patient factors influence surgical outcome following Morton's neuroma excision.

Over a seven-year period, 99 consecutive patients (112 feet) undergoing surgical excision of Morton's neuroma were prospectively studied. 78 patients were female with a mean age at operation of 56 years. Patient recorded outcomes and satisfaction were measured using the Manchester-Oxford Foot Questionnaire (MOXFQ), Short Form-12 (SF12) and a supplementary patient satisfaction survey three months pre and six months post-operatively. Patient demographics were recorded in addition to co-morbidities, deprivation, associated neuroma excision and other forefoot surgery.

Obesity, deprivation and revision surgery proved to statistically worsen MOXFQ outcomes post-operatively (p=0.005, p=0.002 and p=0.004 respectively). Deprivation significantly worsened the mental component of the SF12 (p=0.043) and depression the physical component (p=0.026). No difference in outcome was identified for age, sex, time from diagnosis to surgery, multiple neuroma excision and other forefoot surgeries. 23.5percnt; of deprived patients were dissatisfied with their surgery compared to 7percnt; of the remaining cohort.

Patient reported outcomes following resection of symptomatic Morton's neuroma are shown to be less favourable in those patients who display characteristics of obesity, depression, deprivation and in those who undertake revision neuroma resection. Surgery can be safely delayed, as time to surgery from diagnosis bears no impact on clinical outcome.


The Bone & Joint Journal
Vol. 99-B, Issue 10 | Pages 1399 - 1408
1 Oct 2017
Scott CEH MacDonald D Moran M White TO Patton JT Keating JF

Aims

To evaluate the outcomes of cemented total hip arthroplasty (THA) following a fracture of the acetabulum, with evaluation of risk factors and comparison with a patient group with no history of fracture.

Patients and Methods

Between 1992 and 2016, 49 patients (33 male) with mean age of 57 years (25 to 87) underwent cemented THA at a mean of 6.5 years (0.1 to 25) following acetabular fracture. A total of 38 had undergone surgical fixation and 11 had been treated non-operatively; 13 patients died at a mean of 10.2 years after THA (0.6 to 19). Patients were assessed pre-operatively, at one year and at final follow-up (mean 9.1 years, 0.5 to 23) using the Oxford Hip Score (OHS). Implant survivorship was assessed. An age and gender-matched cohort of THAs performed for non-traumatic osteoarthritis (OA) or avascular necrosis (AVN) (n = 98) were used to compare complications and patient-reported outcome measures (PROMs).


The Bone & Joint Journal
Vol. 99-B, Issue 8 | Pages 1037 - 1046
1 Aug 2017
Scott CEH Turnbull GS MacDonald D Breusch SJ

Aims

Little is known about employment following total knee arthroplasty (TKA). This study aims to identify factors which predict return to work following TKA in patients of working age in the United Kingdom.

Patients & Methods

We prospectively assessed 289 patients (289 TKAs) aged ≤ 65 years who underwent TKA between 2010 and 2013. There were 148 women. The following were recorded pre-operatively: age, gender, body mass index, social deprivation, comorbidities, indication for surgery, work status and nature of employment, activity level as assessed by the University of California, Los Angeles (UCLA) activity score and Oxford Knee Score (OKS). The intention of patients to return to work or to retire was not assessed pre-operatively. At a mean of 3.4 years (2 to 4) post-operatively, the return to work status, OKS, the EuroQol-5 dimensions (EQ-5D) score, UCLA activity score and Work, Osteoarthritis and joint-Replacement (WORQ) score were obtained. Univariate and multivariate analyses were performed.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_12 | Pages 22 - 22
1 Jun 2017
Tadross D Lunn D Redmond A Macdonald D Stone M Chapman G
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In the UK, the posterior approach (PA) and direct lateral approach (DLA) are the most common total hip arthroplasty (THA) procedures. Few studies however, have compared the subsequent functional outcomes. This exploratory study aimed to examine the effect of PA and DLA approaches on post-operative hip kinematics, strength and hip muscle cross-sectional area (CSA), compared to healthy controls.

Participants comprised of 15 cases in the DLA group, > 12 month post-operatively, (ten male, age 68.9+/-5.5 years, BMI 26.9+/-3.0), 13 cases in the PA group (six male; age 72.9+/-6.9 years, BMI 27.1+/-3.6) and 11 age/BMI-matched healthy control participants. All participants underwent 3D kinematic (Vicon, Oxford, UK) and kinetic (AMTI, USA) analysis whist performing self-selected and fast walking as well as sit-to-stand and stand-to-sit. Isometric dynamometry was performed (Biodex Medical systems, USA) for all major muscle groups around the operated hip, and a subset of five participants (three DLA v two PA) underwent “slice encoding for metal artefact correction” (SEMAC) MRI imaging to measure muscle CSA. Patient-reported outcome measures were collected.

Both post-operative surgical groups exhibited altered gait, particularly in limited hip extension, compared to the control participants. The DLA group demonstrated forced hip extension matching controls only under fast walking conditions while the PA group did not achieve hip extension. Both surgical approaches achieved high PROMs scores.

The PA group were weaker for all strength activities tested, whereas the DLA cases demonstrated similar hip strength to controls. SEMAC imaging revealed reduced CSA for those muscles dissected during surgery, compared to the contralateral side.

This exploratory study demonstrated small but measurable differences between surgical approaches for muscle CSA, hip strength of major hip muscle groups and a number of gait variables, although both approaches produce satisfactory functional outcomes for patients after surgery.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_9 | Pages 57 - 57
1 May 2017
Salhab M Macdonald D Kimpson P Freeman J Stewart T Stone M
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Background

Hip arthroplasties are associated with high postoperative pain scores. In some reports, moderate to severe pain was 58% on the first day postoperatively in total hip replacements (THRs). Several techniques are currently used at our institution to tackle acute pain following THRs. These include: 1) Spinal anaesthetic (SA) with Diamorphine only; 2) General anaesthetic (GA) only; 3) SA with local infiltration anaesthetic mixture 1 (LIA1,). Mixture 1 consisted of ropivacaine, adrenaline, and ketorolac; 4) SA with LIA mixture 2 (LIA2). Mixture 2 consisted of bupivacaine and adrenaline; 5) SA with LIA1 and PainKwell pump system. In this study we report on the techniques of acute pain control following THR at our regional centre for elective primary THRs.

Methods

Between June 2011 and July 2014, 173 consecutive patients undergoing primary THR using the posterior approach were prospectively followed up. Group 1. GA only. 31 patients, Group 2. SA only. 37 patients, Group 3. SA plus LIA1 only. 38 patients, Group 4. SA plus LIA2 only, 34 patients, Group 5. SA plus LIA1 plus PainKwell Pump System for 48 hours. 33 patients.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_5 | Pages 13 - 13
1 Mar 2017
Mihalko W Lowell J Woodard E Arnholt C MacDonald D Kurtz S
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Introduction

Total knee arthroplasty (TKA) is a successful procedure for end stage arthritis of the knee that is being performed on an exponential basis year after year. Most surgeons agree that soft tissue balancing of the TKA is a paramount to provide a successful TKA. We utilized a set of retrieved lower extremities with an existing TKA to measure the laxity of the knee in all three planes to see if wear scores of the implants correlated to the laxity measured. This data has never been reported in the literature.

Methods

IRB approval was obtained for the local retrieval program. Each specimen was retrieved after removing the skin, subcutaneous tissue and muscle from mid thigh to mid tibia. The femur, tibia and fibula were then transversely cut to remove the specimen for testing. Each specimen was then imaged using a flouroscopic imaging unit (OEC, Inc) in the AP, Lateral and sunrise views. These images were used to analyze whether there were any signs of osteolysis. Each specimen was mounted into a custom knee testing machine (Little Rock AR). Each specimen then was tested at full extension, 30, 60, and 90 degrees of flexion. At each flexion angle the specimen was subjected to a 10Nm varus and valgus torque, a 1.5Nm internal and external rotational torque and a 35N anterior and posterior directed force. Each specimen's implants were removed to record manufacturer and lot numbers. Polyethylene damage scores (Hood et al. JBMR 1983) were then calculated in the medial, lateral and backside of the polyethylene insert as well as on the medial and lateral femoral condyle. (Figure 1) Correlation coefficients were then calculated to show any relationship with soft tissue balancing in all three planes and wear scores.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_3 | Pages 92 - 92
1 Feb 2017
Day J MacDonald D Kraay M Rimnac C Williams G Abboud J Kurtz S
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Utilization of reverse total shoulder arthroplasty (RTSA) has steadily increased since its 2003 introduction in the American market. Although RTSA was originally indicated for elderly, low demand patients, it is now being increasingly used to treat rotator cuff arthropathy, humeral fractures, neoplasms and failed total and hemi shoulder arthroplasty. There is, therefore, a growing interest in bearing surface wear of RTSA polyethylene humeral liners. In the current study, we examined humeral liners retrieved as part of an IRB approved study to determine the amount of bearing surface wear. We hypothesized that wear of the bearing surface by intentional contact with the glenosphere (mode I) would be minor compared to that produced by scapular notching and impingement of the humeral liner (mode II).

Twenty-three retrieved humeral liners were retrieved at revision surgery after an average of 1.5 years implantation time. The average age at implantation was 68 years (range 50–85). Shoulders were revised for loosening (7), instability (6), infection (6), pain (2), and other/unknown reasons (2). The liners were scanned using microCT at a resolution of 50 µm and then registered against unworn surfaces to estimate the bearing surface wear depth. The depth of surface penetration due to impingement of the liner with surrounding structures was measured and the location of the deepest penetration was noted.

Mode I wear of the bearing surface was detectable for five of the retrieved liners. The penetration depth was 100 µm or less for four of the liners and approximately 250 microns for the fifth liner. It was noted that the liners with discernable mode I wear were those with longer implantation times (average 2.4 years). Material loss and abrasion of the rim due to mode II wear was noted with measurable penetration in 18 of the liners. Mode II wear penetrated to the bearing surface in 11 liners. It was generally noted that volumetric material loss was dominated by mode II wear (Figure 1).

In this study of short to medium term retrieved RTSA humeral liners, mode I wear of the bearing surface was a minor source of material loss. Mode II wear due to scapular notching or impingement of the rim was the dominant source of volumetric wear. This is in agreement with a previous study that we have performed on a smaller cohort of seven liners. It is noteworthy that we were able to detect measurable mode I wear for liners with moderate implantation times. The quantity of bearing surface wear that will be seen in long term retrievals remains unknown at this time.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_3 | Pages 19 - 19
1 Feb 2017
Arnholt C MacDonald D Lowell J Gilbert J Mihalko W Kurtz S
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Introduction

Previous studies of CoCr alloy femoral components for total knee arthroplasty (TKA) have identified 3rd body abrasive wear, and apparent inflammatory cell induced corrosion (ICIC) [1] as potential damage mechanisms. The association between observed surface damage on the femoral condyle and metal ion release into the surrounding tissues is currently unclear. The purpose of this study was to investigate the damage on the bearing surface in TKA femoral components recovered at autopsy and compare the damage to the metal ion concentrations in the synovial fluid.

Methods

12 autopsy TKA CoCr femoral components were collected as part of a multi-institutional orthopedic implant retrieval program. The autopsy components included Depuy Synthes Sigma Mobile Bearing (n=1) and PFC (n=1), Stryker Triathlon (n=1) and Scorpio (n=3), and Zimmer Nexgen (n=4) and Natural Knee (n=2). Fluoro scans of all specimens prior to removal was carried out to assure no signs of osteolysis or aseptic loosening were present.

Third-body abrasive wear of CoCr was evaluated using a semi-quantitative scoring method similar to the Hood method [2]. ICIC damage was reported as location of affected area and confirmed using a digital optical microscope with 4000X magnification.

Synovial fluid was aspirated from the joint capsule prior to removal of the TKA device. The synovial fluid was spun at 1600 rpm for 20 minutes in a centrifuge with the cell pellet removed. The supernatant was analyzed in 1 mL quantities for ICP-MS (inductively coupled plasma mass spectrometry) by Huffman Hazen Laboratories. Data was expressed as ppb.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_4 | Pages 93 - 93
1 Feb 2017
Kurtz S MacDonald D Kocagoz S Arnholt C Underwood R Rimnac C Gilbert J
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Introduction

There is considerable interest in the orthopaedic community in understanding the multifactorial process of taper fretting corrosion in total hip arthroplasty (THA). Previous studies have identified some patient and device factors associated with taper damage, including length of implantation, stem flexural rigidity, and head offset. Due to the complexity of this phenomenon, we approached the topic by developing a series of matched cohort studies, each attempting to isolate a single implant design variable, while controlling for confounding factors to the extent possible. We also developed a validated method for measuring material loss in retrieved orthopaedic tapers, which contributed to the creation of a new international standard (ASTM F3129-16).

Methods

Based on our implant retrieval collection of over 3,000 THAs, we developed independent matched cohort studies to examine (1) the effect of femoral head material (metal vs. ceramic, n=50 per cohort) and (2) stem taper surface finish (smooth vs. microgrooved, n=60 per cohort). Within each individual study, we adjusted for confounding factors by balancing implantation time, stem taper flexural rigidity, offset, and, when possible, head size. We evaluated fretting and corrosion using a four-point semiquantitative score. We also used an out-of-roundness machine (Talyrond 585) to quantify the material loss from the tapers. This method was validated in a series of experiments of controlled material removal on never-implanted components.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_4 | Pages 133 - 133
1 Feb 2017
MacDonald D Caton T Higgs G Malkani A Chen A Mont M Kurtz S
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Background

Sequentially annealed, highly crosslinked polyethylene (HXLPE) has been used clinically in total knee arthroplasty (TKA) for over a decade[1]. However, little is known about the reasons for HXLPE revision, its surface damage mechanisms, or its in vivo oxidative stability relative to conventional polyethylene. We asked whether retrieved sequentially annealed HLXPE tibial inserts exhibited: (1) similar reasons for revision; (2) enhanced resistance to surface damage; and (3) enhanced oxidative stability, when compared with tibial inserts fabricated from conventional gamma inert sterilized polyethylene (control).

Methods

Four hundred and fifty-six revised tibial inserts in two cohorts (sequentially annealed and conventional UHMWPE control) were collected in a multicenter retrieval program between 2000 and 2016. We controlled for implantation time between the two cohorts by excluding tibial inserts with a greater implantation time than the longest term sequentially annealed retrieval (9.5 years). The mean implantation time (± standard deviation) for the sequentially annealed components was 1.9 ± 1.7 years, and for the control inserts, 3.4 ± 2.7 years (Figure 1). Reasons for HXLPE revision were assessed based on medical records, radiographs, and examinations of the retrieved components. Surface damage mechanisms were assessed using the Hood method[2]. Oxidation was measured at the bearing surface, the backside surface, the anterior and posterior faces, as well as the post (when available) using FTIR (ASTM F2102). Surface damage and oxidation analyses were available for 338 of the components. We used nonparametric statistical testing to analyze for differences in oxidation and surface damage when adjusting for polyethylene formulation as a function of implantation time.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_4 | Pages 132 - 132
1 Feb 2017
MacDonald D Chen A Lee G Klein G Cates H Mont M Rimnac C Kurtz S
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Introduction

During revision surgery with a well-fixed stem, a titanium sleeve can be used in conjunction with a ceramic head to achieve better stress distribution across the taper surface. Previous studies have observed that the use of a ceramic head can mitigate the extent of corrosion damage at the taper. Moreover, in vitro testing suggests that corrosion is not a concern in sleeved ceramic heads [1]; however, little is known about the in vivo fretting corrosion of the sleeves. The purpose of this study was to investigate fretting corrosion in sleeved ceramic heads.

Materials and Methods

Thirty sleeved ceramic heads (Biolox Option: CeramTec) were collected during revision surgery as part of a multi-center retrieval program. The sleeves were used in conjunction with a zirconia-toughened alumina femoral head. The femoral heads and sleeves were implanted between 0.0 and 3.25 years (0.8±0.9, Figure 1). The implants were revised predominantly for instability (n=14), infection (n=7), and loosening (n=5). Fifty percent of the retrievals were implanted during a primary surgery, while 50% had a history of a prior revision surgery. Fretting corrosion was scored using a previously described 4-point, semi-quantitative scoring system proposed by Higgs [2].


The Bone & Joint Journal
Vol. 98-B, Issue 12 | Pages 1625 - 1634
1 Dec 2016
Scott CEH Oliver WM MacDonald D Wade FA Moran M Breusch SJ

Aims

Risk of revision following total knee arthroplasty (TKA) is higher in patients under 55 years, but little data are reported regarding non-revision outcomes. This study aims to identify predictors of dissatisfaction in these patients.

Patients and Methods

We prospectively assessed 177 TKAs (157 consecutive patients, 99 women, mean age 50 years; 17 to 54) from 2008 to 2013. Age, gender, implant, indication, body mass index (BMI), social deprivation, range of movement, Kellgren-Lawrence (KL) grade of osteoarthritis (OA) and prior knee surgery were recorded. Pre- and post-operative Oxford Knee Score (OKS) as well as Short Form-12 physical (PCS) and mental component scores were obtained. Post-operative range of movement, complications and satisfaction were measured at one year.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_18 | Pages 10 - 10
1 Nov 2016
Scott C Oliver W MacDonald D Wade F Moran M Breusch S
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Risk of revision following total knee replacement is relatively high in patients under 55 years of age, but little is reported regarding non-revision outcomes. This study aims to identify predictors of dissatisfaction following TKR in patients younger than 55 years of age.

We assessed 177 TKRs (157 consecutive patients) from 2008 to 2013. Data was collected on age, sex, implant, indication, BMI, social deprivation, range of motion, and prior knee surgery in addition to Oxford Knee Score (OKS) and SF-12 score. Postoperative data included knee range of motion, complications, and OKS, SF-12 score and satisfaction measures at one year.

Overall, 24.9% of patients (44/177) were unsure or dissatisfied with their TKR. Significant predictors of dissatisfaction on univariable analysis (p<0.05) included: Kellgren-Lawrence grade 1/2 osteoarthritis; indication; poor preoperative OKS; postoperative complications; and poor improvements in OKS and pain component score (PCS) of the SF-12. Odds ratios for dissatisfaction by indication compared to primary OA: OA with previous meniscectomy 2.86; OA in multiply operated knee 2.94; OA with other knee surgery 1.7; OA with BMI>40kgm-2 2; OA post-fracture 3.3; and inflammatory arthropathy 0.23. Multivariable analysis showed poor preoperative OKS, poor improvement in OKS and postoperative stiffness, particularly flexion of <90°, independently predicted dissatisfaction (p<0.005).

Patients coming to TKR when under 55 years of age differ from the ‘average’ arthroplasty population, often having complex knee histories and indications for surgery, and an elevated risk of dissatisfaction.


The Bone & Joint Journal
Vol. 98-B, Issue 10 | Pages 1376 - 1381
1 Oct 2016
Bucknall V Rutherford D MacDonald D Shalaby H McKinley J Breusch SJ

Aims

This is the first prospective study to report the pre- and post-operative patient reported outcomes and satisfaction scores following excision of interdigital Morton’s neuroma.

Patients and Methods

Between May 2006 and April 2013, we prospectively studied 99 consecutive patients (111 feet) who were to undergo excision of a Morton’s neuroma. There were 78 women and 21 men with a mean age at the time of surgery of 56 years (22 to 78). Patients completed the Manchester-Oxford Foot Questionnaire (MOXFQ), Short Form-12 (SF-12) and a supplementary patient satisfaction survey three months pre-operatively and six months post-operatively.


The Bone & Joint Journal
Vol. 98-B, Issue 7 | Pages 945 - 951
1 Jul 2016
Clement ND MacDonald D Dall GF Ahmed I Duckworth AD Shalaby HS McKinley J

Aims

To examine the mid-term outcome and cost utility of the BioPro metallic hemiarthroplasty for the treatment of hallux rigidius.

Patients and Methods

We reviewed 97 consecutive BioPro metallic hemiarthroplasties performed in 80 patients for end-stage hallux rigidus, with a minimum follow-up of five years. There were 19 men and 61 women; their mean age was 55 years (22 to 74). No patient was lost to follow-up.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_9 | Pages 11 - 11
1 May 2016
MacDonald D Mehta K Klein G Hartzband M Levine H Mont M Kurtz S
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Introduction

Thermally treated 1st generation highly crosslinked polyethylenes (HXLPE) have demonstrated reduced penetration and osteolysis rates, however, concerns still remain with respect to oxidative stability and mechanical properties of these materials. To address these concerns, manufacturers have introduced the use of antioxidants to quench free radicals while maintaining the mechanical properties of the HXLPE. Two common antioxidants are α-tocopherol (Vitamin-E) and pentaerythritol tetrakis (PBHP). These may be either mixed prior to consolidation, or diffused throughout the polymer after consolidation and irradiation. In vitrostudies have shown that these materials are oxidatively stable and have improved mechanical properties compared to 1st generation HXLPEs; however, few studies have investigated the in vivo performance of anti-oxidant stabilized HXLPE. The purpose of this study was to investigate the revision reasons, oxidation, and mechanical properties of retrieved short-term anti-oxidant HXLPE.

Methods

Between 2010 and 2015, 73 anti-oxidant HXLPE components were collected as a part of an IRB approved, multi-institutional retrieval analysis program during routine revision surgery. Of the seventy-three components, 30 (41%) were acetabular liners, whereas, 43 were tibial inserts. The components were fabricated from three different materials: Vitamin-E Diffused HXLPE (n=30; E1, Biomet), Vitamin-E Blended (n = 41; Vivacit-E, Zimmer) and PBHP blended (n = 2, AOX, DePuy). The hip and knee components were implanted for 0.7 ± 0.8 years (Range: 0.0–2.25 years) and 0.8 ± 1.1 years (Range: 0.0–4.5 years), respectively. Implantation time, patient weight, age, gender, and activity levels were similar between hip and knee components (Table 1).

For oxidation analysis, thin slices (∼200μm) were taken from medial condyle and central eminence of the tibial inserts or the superior/inferior axis from hip components. The slices were boiled in heptane for six hours to extract lipids absorbed in vivo. 3-millimeter FTIR line scans were taken perpendicular to the surface of interest, according to the ASTM F2102. Mechanical properties were assessed using the small punch test (ASTM F2183). Forty-three explants were available for destructive testing.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_7 | Pages 23 - 23
1 May 2016
Arnholt C MacDonald D Kocagoz S Chen A Cates H Klein G Rimnac C Kurtz S
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Introduction

Previous studies of long-term CoCr alloy femoral components for TKA have identified 3rd body abrasive wear and inflammatory cell induced corrosion (ICIC). The extent of femoral condyle surface damage in contemporary CoCr femoral components is currently unclear. The purpose of this study was to investigate the prevalence and morphology of damage (3rd body scratches and ICIC) at the bearing surface in retrieved TKA femoral components from contemporary designs.

Methods

308 CoCr femoral TKA components were collected as part of an ongoing, multi-institutional orthopedic implant retrieval program. The collection included contemporary designs from Stryker (Triathlon n=48, NRG n=10, Scorpio n=31), Depuy Synthes (PFC n=27) and Zimmer (NexGen n=140, Persona n=1) and Biomet (Vanguard n=51). Hinged knee designs and unicondylar knee designs were excluded. Components were split into groups based on implantation time: short-term (1–3y, n=134), intermediate-term (3–5y, n=73) and long-term (6–15y, n=101). Each grouping was mainly revised for instability, infection and loosening.

Third-body abrasive wear of CoCr was evaluated using a semi-quantitative scoring method similar to the Hood method (Figure 1). A score of 1 had minimal damage and a score of 4 corresponded to damage covering more than 50% of the evaluated area. ICIC damage was reported as location of affected area. A white light interferometer (Zygo New View 5000) was also used to analyze the topography of severe damage of the bearing surface. For this analysis, three representative components from each cohort were selected and analyzed in three locations on the apex of the bearing surface. We analyzed the following roughness parameters: Ra, Rsk, and Rku.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_9 | Pages 10 - 10
1 May 2016
MacDonald D Schachtner J Chen A Cates H Klein G Mont M Kraay M Malkani A Lee G Hamlin B Rimnac C Kurtz S
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Introduction

Highly crosslinked polyethylene (HXLPE) was clinically introduced approximately a decade and a half ago to reduce polyethylene wear rates and subsequent osteolysis. Clinical and radiographic studies have repeatedly shown increased wear resistance, however concerns of rim oxidation and fatigue fracture remain. Although short to intermediate term retrieval studies of these materials are available, the long-term behavior of these materials remains unclear.

Methods

Between 2000 and 2015, 115 1st generation HXLPE acetabular liners implanted for 5 or more years were collected and analyzed as part of an ongoing, multi-institutional orthopaedic implant retrieval program. There were two material cohorts based on thermal processing (annealed (n=45) and remelted (n=70)). Each cohort was stratified into two more cohorts based on implantation time (5 – 10 years and >10 years). For annealed components, the intermediate-term liners (n=30) were implanted on average (±SD) for 7.3 ± 1.7 years while the long-term liners (n=15) were implanted for 11.3 ± 1.8 years. For remelted components, the intermediate-term liners (n=59) were implanted on average (±SD) for 7.2 ± 1.3 years while the long-term liners (n=11) were implanted for 11.3 ± 1.2 years. For each cohort, the predominant revision reasons were loosening, instability, and infection (Figure 1). Short-term liners (in-vivo <5ys) from previous studies were analyzed using the same protocol for use as a reference.

For oxidation analysis, thin slices (∼200 μm) were taken from the superior/inferior axis and subsequently boiled in heptane for 6 hours to remove absorbed lipids that may interfere with the oxidation analysis. 3mm line profiles (in 100μm increments) were taken perpendicular to the surface at each region of interest. Oxidation indices were calculated according to ASTM 2102. Penetration was measured directly using a calibrated micrometer (accuracy=0.001mm).


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_8 | Pages 129 - 129
1 May 2016
Kurtz S Arnholt C MacDonald D Higgs G Underwood R Chen A Klein G Hamlin B Lee G Mont M Cates H Malkani A Kraay M Rimnac C
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Introduction

Previous studies of retrieved CoCr alloy femoral heads have identified imprinting of the stem taper surface features onto the interior head bore, leading researchers to hypothesize that stem taper microgrooves may influence taper corrosion. However, little is known about the role of stem taper surface morphology on the magnitude of in vivo corrosion damage. We designed a matched cohort retrieval study to examine this issue.

Methods

From a multi-institutional retrieval collection of over 3,000 THAs, 120 femoral head-stem pairs were analyzed for evidence of fretting and corrosion using a visual scoring technique based on the severity and extent of fretting and corrosion damage observed at the taper. A matched cohort design was used in which 60 CoCr head-stem pairs with a smooth stem taper were matched with 60 CoCr head-stem pairs having a micro-grooved surface, based on implantation time, flexural rigidity, apparent length of taper engagement, and head size. This study was adequately powered to detect a difference of 0.5 in corrosion scores between the two cohorts, with a power of 82% and 95% confidence. Both cohorts included CoCr and Ti-6-4 alloy femoral stems. A high precision roundness machine (Talyrond 585, Taylor Hobson, UK) was used to measure surface morphology and categorize the stem tapers into smooth vs. micro-grooved categories. Fretting and corrosion damage at the head/neck junction was characterized using a modified semi-quantitative adapted from the Goldberg method by three independent observers. This method separated corrosion damage into four visually determined categories: minimal, mild, moderate and severe damage.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_2 | Pages 118 - 118
1 Jan 2016
Kocagoz S Underwood RJ Baykal D MacDonald D Day J Kurtz S
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Introduction

In total joint replacement devices, material loss from the taper junctions is a clinical concern. Previous studies of explanted orthopedic devices have relied on visual scoring methods to quantify the fretting-corrosion damage on the component interfaces. Previous research has shown that visual fretting-corrosion evaluation is correlated to the volume of material loss [1], but scoring is semi-qualitative and does not provide a quantitative measure of the amount of material removed from the surface. The purpose of this study was to develop and validate a quantitative method for measuring the volume of material lost from the surfaces of explanted devices at the taper-trunnion junction.

Methods

10 new exemplar taper adapter sleeves (Ceramtec, Plochingen, Germany) were used for method validation. By using exemplar devices we were able to create clinically realistic taper damage in a controlled and repeatable manner using machining tools. Taper surfaces were measured before and after in vitro material removal using a roundness machine (Talyrond 585, Taylor Hobson, UK). Axial traces were measured on each taper surface using a diamond stylus. The mass of artificially removed material was also measured gravimetrically using a microgram balance (Sartorius, CPA225D, accuracy = ± 0.00003g).

Surface profiles were analyzed using a custom MatLab script and Talymap software was used to provide 3D visualizations of the pattern of material loss. Calculated volumetric material loss was compared to the gravimetric value. A sensitivity analysis was conducted to determine the optimum number of traces to characterize the material loss from taper junctions.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_1 | Pages 108 - 108
1 Jan 2016
Day J MacDonald D Arnholt C Williams G Getz C Kraay M Rimnac C Kurtz S
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INTRODUCTION

Mechanically assisted crevice corrosion of taper interfaces was raised as a concern in total hip arthroplasty (THA) approximately 20 years ago (Gilbert 1993). In total shoulder replacement, however, comparatively little is known about the prevalence of fretting assisted crevice corrosion or the biomechanical and patient factors that influence this phenomenon. Given the comparatively lower loading experienced in the shoulder compared to the hip, we asked: (1) What is the prevalence of fretting assisted corrosion in modular total shoulder replacements, and (2) What patient and implant factors are associated with corrosion?

METHODS

Modular components were collected from 48 revision shoulder arthroplasties as part of a multi-center, IRB approved retrieval program. For anatomic shoulders, this included 40 humeral heads, 32 stems and four taper adapters from seven manufacturers. For reverse shoulders, there were eight complete sets of retrieved components from three manufacturers. The components were predominantly revised for instability, loosening and pain. Anatomical shoulders were implanted for an average of 3.1 years (st dev 3.8; range 0.1–14.5). Reverse shoulders were implanted for an average of 2.2 years (st dev 0.7; range 1.3–3.3). Modular components were disassembled and examined for taper damage. The modular junctions were scored for fretting corrosion using a semi-quantitative four-point scoring system adapted from Goldberg, et al. (Goldberg, 2002, Higgs 2013). The scoring system criteria was adapted from Goldberg and Higgs which is comprised of a one to four grading system (with one indicating little-to-no fretting/corrosion and four indicating extensive fretting/corrosion). The component alloy composition was determined using the manufacturer's laser markings and verified by x-ray fluorescence. Patient age, gender, hand dominance, alloy, flexural rigidity of the trunnion and taper geometry were assessed independently as predictors for fretting corrosion.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_3 | Pages 3 - 3
1 Jan 2016
MacDonald D Baykal D Underwood R Malkani AL Parvizi J Kurtz SM
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Introduction

First-generation annealed HXLPE has been clinically successful at reducing both clinical wear rates and the incidence of osteolysis in total hip arthroplasty. However, studies have observed oxidative and mechanical degradation occurring in annealed HXLPE. Thus, it is unclear whether the favorable clinical performance of 1st generation HXLPE is due to the preservation of bearing surface tribological properties or, at least partially, to the reduction in patient activity. The purpose of this study was to evaluate the in vitro wear performance (assessed using multidirectional pin-on-disk (POD) testing) of 1st-generation annealed HXLPE with respect to in vivo duration, clinical wear rates, oxidation, and mechanical properties.

Materials and Methods

103 1st-generation annealed HXLPE liners were collected at revision surgery. 39 annealed HXLPE liners were selected based on their implantation time and assigned to three equally sized cohorts (n=13 per group); short-term (1.4–2.7y), intermediate term (5.2–8.0y) and long-term (8.3–12.5y). From each retrieved liner, two 9-mm cores were obtained (one from the superior region and one from the inferior region). Sixteen cores were fabricated from unimplanted HXLPE liners that were removed from their packaging and six pins from unirradiated GUR 1050 resin served as positive controls. Multidirectional POD wear testing was conducted against wrought CoCr disks in a physiologically relevant lubricant (20 g/L protein concentration) using a 100-station SuperPOD (Phoenix Tribology, UK). Each pin had its own chamber with 15mL lubricant maintained at 37±1°C. An elliptical wear pattern with a static contact stress of 2.0 MPa was employed. Testing was carried out to 1.75 million cycles at 1.0 Hz and wear was assessed gravimetrically. POD wear rates were calculated using a linear regression of volumetric losses. In vivo penetration was measured directly using a calibrated micrometer. Oxidation was assessed on thin films obtained from superior and inferior regions of the liners (ASTM 2102). Mechanical properties were assessed using the small punch test (ASTM 2183).


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_3 | Pages 4 - 4
1 Jan 2016
MacDonald D Clarkin-Wright G Parvizi J Lee G Klein G Rimnac C Gilbert J Kurtz S
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Introduction

In THA, fretting corrosion at the head-stem taper junction has emerged as a clinical concern that may result in adverse local tissue reactions, even in patients with a metal-on-polyethylene bearing [1]. Taper junctions that employ a ceramic head have demonstrated reduced corrosion at the interface [2]. However, during revision surgery with a well-fixed stem, a titanium sleeve is used in conjunction with a ceramic head to ensure proper fit of the head onto the stem and better stress distribution. In vitro testing has suggested that corrosion is not a concern in sleeved ceramic heads [3]; however, little is known about the in vivo fretting corrosion of the sleeves. The purpose of this study was to investigate fretting corrosion in sleeved ceramic heads.

Materials and Methods

Between 2001 and 2014, 35 sleeved ceramic heads were collected during revision surgery as part of a multi-center retrieval program. The sleeves were all fabricated from titanium alloy and manufactured by 4 companies (CeramTec (n=14), Smith & Nephew (Richards, n=11), Stryker (n=5), and Zimmer (n=5)). The femoral heads were made from 3 ceramics (Alumina (n=7), Zirconia (n=11), and Zirconia-toughened Alumina (n=17)). Sleeve dimensions (length and thickness) were measured using calibrated calipers. Fretting corrosion of the sleeves and available associated stems was scored using a 4-point, semi-quantitative scoring system [4], with 1 being little-to-no damage, and 4 corresponded to severe fretting corrosion. Five sleeves could not be extracted; thus the external surface was not scored.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_2 | Pages 132 - 132
1 Jan 2016
MacDonald D Kurtz SM Kocagoz S Hanzlik J Underwood RJ Gilbert J Lee G Mont M Kraay M Klein GR Parvizi J Day J Rimnac C
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Introduction

Recent implant design trends have renewed concerns regarding metal wear debris release from modular connections in THA. Previous studies regarding modular head-neck taper corrosion were largely based on cobalt chrome (CoCr) alloy femoral heads. Comparatively little is known about head-neck taper corrosion with ceramic femoral heads or about how taper angle clearance influences taper corrosion. This study addressed the following research questions: 1) Could ceramic heads mitigate electrochemical processes of taper corrosion compared to CoCr heads? 2) Which factors influence stem taper corrosion with ceramic heads? 3) What is the influence of taper angle clearance on taper corrosion in THA?

Methods

100 femoral head-stem pairs were analyzed for evidence of fretting and corrosion. A matched cohort design was employed in which 50 ceramic head-stem pairs were matched with 50 CoCr head-stem pairs based on implantation time, lateral offset, stem design and flexural rigidity. Fretting corrosion was assessed using a semi-quantitative scoring scale where a score of 1 was given for little to no damage and a score of 4 was given for severe fretting corrosion. The head and trunnion taper angles were measured using a roundness machine (Talyrond 585, Taylor Hobson, UK). Taper angle clearance is defined as the difference between the head and trunnion taper angles.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_1 | Pages 26 - 26
1 Jan 2016
Arnholt C Kocagoz S MacDonald D Gilbert J Parvizi J Malkani AL Klein GR Kraay M Rimnac C Kurtz S
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Introduction

The release of metal debris and ions has raised concerns in joint arthroplasty. In THA metal debris and ions can be generated by wear of metal-on-metal bearing surfaces and corrosion at modular taper interfaces, currently understood to be mechanically assisted crevice corrosion (MACC) [1]. More recently, inflammatory-cell induced corrosion (ICIC) has been identified as a possible source of metal debris and/or ions [2]. Although MACC has been shown to occur at modular junctions in TKA, little is known about the prevalence of other sources. The purpose of this study was to determine the sources of metallic debris and ion release in long-term implanted (in vivo > 15y) TKA femoral components. Specific attention was paid to instances of ICIC as well as damage at the implant-bone interface.

Methods

1873 retrieved TKA components were collected from 2002–2013 as part of a multi-center, IRB-approved retrieval program. Of these, 52 CoCr femoral condyles were identified as long term TKA (Average: 17.9±2.8y). These components were predominantly revised for loosening, PE wear and instability. 40/52 of the components were primary surgeries. Components were examined using optical microscopy to confirm the presence of 5 damage mechanisms (polyethylene failure, MACC corrosion of modular tapers, corrosion damage between cement and backside, third-body wear, and ICIC). Third-body wear was evaluated using a semi-quantitative scoring method based on the percentage of damaged area. A score of 1 had minimal damage and a score of 4 corresponded to severe damage. Polyethylene components were scored using the Hood method and CoCr components were scored similarly to quantify metal wear. The total area damaged by ICIC was quantified using photogrammetry. Images were taken using a digital SLR with a calibrated ruler in the same focal plane. Using known pixel dimensions, the ICIC damaged area was calculated.


Orthopaedic Proceedings
Vol. 97-B, Issue SUPP_14 | Pages 27 - 27
1 Dec 2015
Bucknall V Rutherford D Macdonald D Shalaby H McKinley J Breusch S
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Current knowledge regarding outcomes following surgical treatment of Morton's neuroma remains incomplete. This is the first prospective study to report the pre- and post-operative patient reported outcomes and satisfaction scores following excision of interdigital Morton's neuroma.

Over a seven year period, 99 consecutive patients (112 feet) undergoing surgical excision of Morton's neuroma were prospectively studied. 78 patients were female with a mean age at operation of 56 years. Patient recorded outcomes and satisfaction were measured using the Manchester-Oxford Foot Questionnaire (MOXFQ), Short Form-12 (SF12) and a supplementary patient satisfaction survey three months pre and six months post-operatively.

Statistically significant differences were found between the mean pre- and post-operative MOXFQ and physical component of the SF-12 (p< 0.05). No difference in outcome was identified in patients in whom multiple neuromas were operated compared to single site surgery. However, revision surgery proved to statistically worsen MOXFQ outcomes post-operatively p< 0.004. Overall satisfaction was reported as excellent (49%) or good (29%) by the majority of patients but 10% were dissatisfied with poor (8%) or very poor (2%) results expressed. Only 64% were pain free at the time of follow-up and 8% of patients MOXFQ scores worsened.

These findings illustrate that overall, patient reported outcomes following resection of symptomatic Morton's neuroma are acceptable but may not be as favourable as earlier studies suggest. Caution should be taken when considering revision surgery which has shown to be a poor prognostic indicator. Contrary to current knowledge, multiple site surgery can be safely undertaken.


Orthopaedic Proceedings
Vol. 97-B, Issue SUPP_17 | Pages 3 - 3
1 Dec 2015
Bucknall V Rutherford D Macdonald D Shalaby H McKinley J Breusch S
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Current knowledge regarding outcomes following surgical treatment of Morton's neuroma remains incomplete. This is the first prospective study to report the pre- and post-operative patient reported outcomes and satisfaction scores following excision of interdigital Morton's neuroma.

Over a seven year period, 99 consecutive patients (112 feet) undergoing surgical excision of Morton's neuroma were prospectively studied. 78 patients were female with a mean age at operation of 56 years. Patient recorded outcomes and satisfaction were measured using the Manchester-Oxford Foot Questionnaire (MOXFQ), Short Form-12 (SF12) and a supplementary patient satisfaction survey three months pre and six months post-operatively.

Statistically significant differences were found between the mean pre- and post-operative MOXFQ and physical component of the SF-12 (p<0.05). No difference in outcome was identified in patients in whom multiple neuromas were operated compared to single site surgery. However, revision surgery proved to statistically worsen MOXFQ outcomes post-operatively p<0.004. Overall satisfaction was reported as excellent (49%) or good (29%) by the majority of patients but 10% were dissatisfied with poor (8%) or very poor (2%) results expressed. Only 64% were pain free at the time of follow-up and 8% of patients MOXFQ scores worsened.

These findings illustrate that overall, patient reported outcomes following resection of symptomatic Morton's neuroma are acceptable but may not be as favourable as earlier studies suggest. Caution should be taken when considering revision surgery which has shown to be a poor prognostic indicator. Contrary to current knowledge, multiple site surgery can be safely undertaken.


Orthopaedic Proceedings
Vol. 97-B, Issue SUPP_17 | Pages 7 - 7
1 Dec 2015
Clement N MacDonald D Burnett R Simpson A Howie C
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This study assessed whether patient satisfaction with their hospital stay influences the early outcome of total knee replacement (TKR).

During a five year period patients undergoing primary TKR at the study centre had prospectively outcome data recorded (n=2264). Patients with depression (p=0.04) and worse mental wellbeing (p<0.001), according to the short form (SF)-12, were more likely to be dissatisfied with their hospital stay. Decreasing level of satisfaction with their hospital stay was associated with a significantly worse post-operative OKS (p<0.001) and SF-12 score (p<0.001). Multivariable regression analysis confirmed that the patients perceived level of satisfaction with their hospital stay was an independent predictor of change in the OKS (p<0.001) and SF-12 score (p<0.001) after adjusting for confounding variables. Patient satisfaction with their TKR was significantly influenced by their hospital experience, decreasing from 96% in those with an excellent experience to 42% in those with a poor experience. Food, staff/care, and the hospital environment were the most frequent reasons of why patients rated their hospital experience as fair or poor.

A patient's perception of their inpatient hospital experience after surgery is an important modifiable predictor of early functional outcome and satisfaction with TKR.


Orthopaedic Proceedings
Vol. 97-B, Issue SUPP_3 | Pages 14 - 14
1 Apr 2015
Halai M Augustine A Holloway N MacDonald D Mohammed A Meek R Patil S
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Two major challenges in arthroplasty are obesity and antibiotic resistance. This study was performed to characterise the organisms responsible for deep infection following total hip arthroplasty and to determine if obesity affected the microbiology profile.

A retrospective analysis of the national surgical site infection register was made to obtain data regarding deep infection following 10948 primary total hip arthroplasty (THA) from 1998–2013, with a minimum of 2 year follow-up.

Of all the primary THAs performed, there were 108 deep infections (56 patients had a BMI >30 (obese) and 52 patients <30). There were no significant differences between cardio-respiratory disease, smoking and alcohol status, and diabetes between the 2 groups. Over the last 15 years, staphylococcus aureus continues to be the most frequently isolated organism. Infection with multiple organisms was found exclusively in obese patients. Furthermore, in obese patients, there was a linear increase with methicillin resistant staphylococcus aureus (MRSA) infections and streptococcus viridans.

On this basis, we recommend careful selection of antibiotic therapy in obese patients, rather than empirical therapy, which can be especially important if there is no growth in an infected THA. In addition, a preoperative discussion regarding dental prophylaxis against streptococcus viridans may be warranted.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 154 - 154
1 Jul 2014
Kurtz S Zielinska O MacDonald D Cates H Mont M Malkani A Parvizi J Kraay M Rimnac C Klein G
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Summary Statement

This study assesses oxidation, mechanical behavior and revision reasons of 2nd generation HXLPE used in total hip and knee arthroplasty. While oxidation was low for both X3 and E1 HXLPEs, oxidative regional variations were detected in the sequentially annealed cohort.

Introduction

First generation highly crosslinked polyethylenes (HXPLEs) have proven successful in lowering both penetration and osteolysis rates. However, 1st generation annealing and remelting thermal stabilization have been associated with in vivo oxidation or reduced mechanical properties. Thus, 2nd generation HXLPEs were developed to improve oxidative stability while still maintaining material properties. Little is known about the in vivo clinical failure modes of these 2nd generation HLXPEs. The purpose of this study was to assess the revision reasons, wear, oxidative stability, and mechanical behavior of retrieved sequentially annealed Vitamin E diffused HXLPE in THA and TKA.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 145 - 145
1 Jul 2014
Kurtz S MacDonald D Higgs G Gilbert J Klein G Mont M Parvizi J Kraay M Rimnac C
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Summary Statement

Fretting and corrosion has been identified as a clinical problem in modular metal-on-metal THA, but remains poorly understood in modern THA devices with polyethylene bearings. This study investigates taper damage and if this damage is associated with polyethylene wear.

Introduction

Degradation of modular head-neck tapers was raised as a concern in the 1990s (Gilbert 1993). The incidence of fretting and corrosion among modern, metal-on-polyethylene and ceramic-on-polyethylene THA systems with 36+ mm femoral heads remains poorly understood. Additionally, it is unknown whether metal debris from modular tapers could increase wear rates of highly crosslinked PE (HXLPE) liners. The purpose of this study was to characterise the severity of fretting and corrosion at head-neck modular interfaces in retrieved conventional and HXLPE THA systems and its effect on penetration rates.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 29 - 29
1 Jul 2014
Hamilton D Lane J Gaston P Patton J MacDonald D Simpson H Howie C
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Summary Statement

Service industry metrics (the net promoter score) are being introduced as a measure of UK healthcare satisfaction. Lower limb arthroplasty, as a ‘service’, scores comparably with the most successful commercial organisations.

Background

Satisfaction with care is important to both the patient and the payer. The Net Promoter Score, widely used in the service industry, has been recently introduced to the UK National Health Service as an overarching metric of patient satisfaction and to monitor performance. This questionnaire asks ‘customers’ if they would recommend a service or products to others. Scores range from −100 (everyone is a detractor) to +100 (everyone is a promoter). In industry, a positive score is well regarded, with those over 50 regarded as excellent. Our aims were to assess net promoter scores for joint arthroplasty, to compare these scores with direct measures of patient satisfaction, and to evaluate which factors contributed to net promoter response.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_7 | Pages 15 - 15
1 Apr 2014
Sciberras N Millar S Macdonald D
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In our department, currently there is variation in the number of xrays that patients receive following ORIF of distal radius fractures.

This audit investigated the use of xrays following ORIF of distal radius fractures. Patients were identified from daily trauma lists. Patients who had a primary ORIF or ORIF following failed conservative management were included in the study. PACS was used to identify the number of post-operative xrays performed. These were correlated with clinic letters to see if there was any change in management following xray review.

Between July and November 2013, 102 patients were admitted with distal radius fracture. Of these, 35 (mean age:51 years) had an ORIF. Four were not followed-up in Scotland. Of the remaining 31 patients, eleven had one post-operative xray, seventeen had two and three had three xrays. Of the patients who had one xray, seven had the xray in the first three weeks, the rest at six weeks. Patients who had two xrays had an xray at two and 6 weeks. Of the three patients who had three xrays, two had comminuted fractures that required further CT investigation, one for a suspicion of an intra-articular screw, the other for possibility of non-union. The third patient had no apparent reason for requiring three xrays. Thus of the 31 patients in the study, 29 did not require any further investigations.

The results show a variation in the frequency of post-operative xrays after fixation of distal radius fractures. In most cases the management plan was unchanged after plain xrays were undertaken. This suggests that a protocol driven approach to follow-up after fixation of distal radius fractures could reduce the burden on fracture clinic and radiology departments.

We propose that unless indicated by intra-operative findings or post-operative concerns, patients should have xrays at the two week review appointment.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_3 | Pages 2 - 2
1 Feb 2014
Jenkins P Ramaesh R Lane J Knight S MacDonald D Howie C
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Many psychological factors have been associated with function after joint replacement. Personality is a stable pattern of responses to external conditions and stimuli. The aim of this study was to investigate the relationship between personality, joint function, and general physical in patients undergoing total hip (THR) and knee replacement (TKR).

We undertook a prospective cohort study of 184 patients undergoing THA and 205 undergoing TKA. Personality was assesed using the Eysneck Personality Questionaire, brief version (EPQ-BV). Physical health was measured using the EuroQol (EQ-5D). Joint function was measured using the relevant Oxford Score. Outcomes were assessed at six months. Multivariable models were constructed.

The stable introvert personality was most common. Unstable introverts had poorer pre-operative function with hip arthrosis, but not knee arthrosis. Personality was not directly associated with post-operative function – the only independent predictors were pre-operative function (p=0.002) and comorbidity (p<0.001). While satisfaction after TKR was associated with personality (p=0.026), there was no association after THR (p=0.453). The poorest satisfaction was in those with the unstable introvert personality type.

Personality was a predictor of preoperative status. It did not have a direct association with postoperative status, but may have as preoperative function was the main predictor of postoperative function, personality may have had an indirect effect. Personality was also a predictor of satisfaction after TKR. This suggests that predicting satisfaction after knee replacement is more complex. Therefore certain patient may benefit from a tailored preoperative education to explore and manage expectations.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_3 | Pages 13 - 13
1 Feb 2014
Turnbull G MacDonald D Clement N Howie C
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Expectations of patients requiring knee arthroplasty surgery have become higher than in the past, with more strain being put on modern prostheses by fitter and younger patients. The objective of this study was to analyse the survivorship of primary knee arthroplasties at a minimum of ten years, with end points of revision and death. Patients who had a total (TKA) or unicompartmental (UKA) knee arthroplasty performed at a university teaching hospital were identified from the local arthroplasty database. Electronic and operative records were analysed to determine parameters including operative indication, subsequent revision surgery, and patient mortality. Results were collated and analysed using PASW software.

A total of 1023 patients were recruited, with 566 (55%) female and 457 (45%) male. Minimum follow up was 10.1 years, with an average of 12.1 years (S.D 0.87). 64.9% of patients were alive at follow up, with an average age of 79.7 years (S.D 8.7). 92.8% were operated on for osteoarthritis (OA), 6.6% for rheumatoid arthritis (RA) and 0.6% for other indications. Kaplan–Meier analysis estimated survival of 94% (S.D 0.008) at eleven years, with no statistical difference found in survivorship of knees operated on for OA or RA. Similarly no statistical difference was found between survivorship of UKA or TKA implants. Of those that died by follow up, 95.2% did so with their original implant.

We conclude that both TKA and UKA offer a lasting solution for patients, with excellent outcomes achieved in both rheumatoid and osteoarthritic patients.


The Bone & Joint Journal
Vol. 95-B, Issue 12 | Pages 1632 - 1639
1 Dec 2013
Clement ND MacDonald D Simpson AHRW Burnett R

This study assessed the effect of concomitant back pain on the Oxford knee score (OKS), Short-Form (SF)-12 and patient satisfaction after total knee replacement (TKR). It involved a prospectively compiled database of demographics and outcome scores for 2392 patients undergoing primary TKR, of whom 829 patients (35%) reported back pain. Compared with those patients without back pain, those with back pain were more likely to be female (odds ratio (OR) 1.5 (95% confidence interval (CI) 1.3 to 1.8)), have a greater level of comorbidity, a worse pre-operative OKS (2.3 points (95% CI 1.7 to 3.0)) and worse SF-12 physical (2.0 points (95% CI 1.4 to 2.6)) and mental (3.3 points (95% CI 2.3 to 4.3)) components.

One year post-operatively, those with back pain had significantly worse outcome scores than those without with a mean difference in the OKS of 5 points (95% CI 3.8 to 5.4), in the SF-12 physical component of 6 points (95% CI 5.4 to 7.1) and in the mental component of 4 points (95% CI 3.1 to 4.9). Patients with back pain were less likely to be satisfied (OR 0.62, 95% CI 0.5 to 0.78).

After adjusting for confounding variables, concomitant back pain was an independent predictor of a worse post-operative OKS, and of dissatisfaction. Clinicians should be aware that patients suffering concomitant back pain pre-operatively are at an increased risk of being dissatisfied post-operatively.

Cite this article: Bone Joint J 2013;95-B:1632–9.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 386 - 386
1 Dec 2013
Kurtz S Zielinska O MacDonald D Cates H Mont M Malkani AL Parvizi J Rimnac C
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Introduction:

First generation highly crosslinked polyethylenes (HXPLEs) have proven successful in lowering both penetration and osteolysis rates. However, 1st generation annealing and remelting thermal stabilization have been associated with in vivo oxidation or reduced mechanical properties. Thus, 2nd generation HXLPEs were developed to improve oxidative stability while still maintaining material properties. Little is known about the in vivo clinical failure modes of these 2nd generation HLXPEs.

The purpose of this study was to assess the revision reasons, wear, oxidative stability, and mechanical behavior of retrieved sequentially annealed Vitamin E diffused HXLPE in THA and TKA.

Methods:

251 2nd Generation HXLPE hip and knee components were consecutively retrieved during revision surgeries and continuously analyzed in a prospective, IRB approved, multicenter study. 123 acetabular liners (Implanted 1.2y; Range 0–5.0y) and 117 tibial inserts (Implanted 1.6y; Range 0–5.8y) were highly crosslinked and annealed in 3 sequential steps (X3). Five acetabular liners (Implanted 0.6y; Range 0–2.0y) and six tibial inserts (Implanted 1.3y; Range 0.5–1.8y) were diffused with Vitamin E (E1). Patient information was collected from medical records (Table 1).

Linear penetration of liners was measured using a calibrated digital micrometer (accuracy: 0.001 mm). Surface damage of tibial components was assessed using the Hood method. Thin sections were taken from the acetabular liners (along the superior/inferior axis) and the tibial components (along the medial condyle and central spine) for oxidation analysis and analyzed according to ASTM 2102. Mechanical behavior was assessed via the small punch test (ASTM 2183).


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 110 - 110
1 Dec 2013
MacDonald D Kurtz S Kocagoz S Hanzlik J Underwood R Gilbert J Lee G Mont M Kraay M Klein GR Parvizi J Rimnac C
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Background:

Previous studies regarding modular head-neck taper corrosion were largely based on cobalt chrome (CoCr) alloy femoral heads. Less is known about head-neck taper corrosion with ceramic femoral heads.

Questions/purposes:

We asked (1) whether ceramic heads resulted in less taper corrosion than CoCr heads; (2) what device and patient factors influence taper fretting corrosion; and (3) whether the mechanism of taper fretting corrosion in ceramic heads differs from that in CoCr heads.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 387 - 387
1 Dec 2013
Kurtz S MacDonald D Higgs G Gilbert J Klein GR Mont M Parvizi J Kraay M Rimnac C
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Introduction:

Degradation of modular head-neck tapers was raised as a concern in the 1990s (Gilbert 1993). The incidence of fretting and corrosion among modern, metal-on-polyethylene and ceramic-on-polyethylene THA systems with 36+ mm femoral heads remains poorly understood. Additionally, it is unknown whether metal debris from modular tapers could increase wear rates of highly crosslinked PE (HXLPE) liners.

The purpose of this study was to characterize the severity of fretting and corrosion at head-neck modular interfaces in retrieved conventional and HXLPE THA systems and its effect on penetration rates.

Patients & Methods:

386 CoCr alloy heads from 5 manufacturers were analyzed along with 166 stems (38 with ceramic femoral heads). Metal and ceramic components were cleaned and examined at the head taper and stem taper by two investigators. Scores ranging from 1 (mild) to 4 (severe) were assigned in accordance with the semi-quantitative method adapted from a previously published technique. Linear penetration of liners was measured using a calibrated digital micrometer (accuracy: 0.001 mm). Devices implanted less than 1 year were excluded from this analysis because in the short-term, creep dominates penetration of the head into the liner.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_33 | Pages 9 - 9
1 Sep 2013
Whitgift J Howie C Mandziak D Cheng C MacDonald D
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Nerve damage is a complication of THA and TKA procedures. The incidence of subclinical nerve injury following arthroplasty is unknown. The aim was to determine the prevalence of asymptomatic nerve deficits in an arthroplasty population group, and the incidence of post-operative changes in nerve function. A Secondary aim was to identify the nature of any deficits. And the association between nerve deficits and history of backache.

A non-randomised prospective series of patients undergoing lower limb arthroplasty for osteoarthritis were studied at a single hospital. The peroneal nerve was investigated using nerve conduction in forty patients. Twenty patients had upper limb testing to differentiate between a polyneuropathy or isolated lower limb neuropathy.

Nerve function deficits were detected in the peroneal nerve in fifteen patients pre-operatively and fifteen post-operatively, of those twelve had A waves detected suggestive of a generalised neuropathy. Ten patients who had upper limb testing had a conduction defect (five had asymptomatic Carpal tunnel). There was a positive correlation between presence of post-operative deficit and age(r=0.389, p=0.013). A negative correlation was found for presence of post-operative A waves and BMI(r=−0.370, p=0.019).

The prevalence of pre-operative subclinical peroneal neuropathy is much higher than expected in this group (37.5%) of arthroplasty patients. There is a strong correlation between presence of post-operative conduction abnormalities and age. There is no relationship between peripheral neuropathy and history of backache or residual post-operative deficit.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_30 | Pages 39 - 39
1 Aug 2013
Baird E Macdonald D Gilmour A Kumar C
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We aimed to review the outcome of Agility total ankle replacements carried out in our institution between 2002 and 2006.

Follow-up consisted of clinical and radiological review pre-operatively, then at 6 weeks, 6 and 12 months, and annually until 10 years post op. Clinical review included the American Orthopaedic Foot and Ankle Score, satisfaction and pain scores. Case notes were reviewed to determine intra and post-operative complications.

30 arthroplasties were performed in 30 consecutive patients. Pre-operative diagnosis was rheumatoid arthritis(16), primary osteoarthritis(12) and post-traumatic osteoarthritis(2). After a mean follow up of 6.2 years (1.4–10.1), 4 patients had died, and 22 out of the remaining 24 were available for follow-up. Intra operative complications included lateral malleoli fracture(3) and superficial peroneal nerve injury(2). Post operative complications included 1 early death, but this was not related to the surgical procedure. Two patients developed deep infections of the prosthesis. One underwent removal of the implant; the other is on long term oral antibiotic therapy. One patient had delayed union of the syndesmosis and six patients had non-union. On clinical assessment, patients' AOFAS scores improved from mean 40.4 pre-op to 83.5 post-op (p<0.001). Radiological assessment of the tibial component revealed 25 (93%) patients had lucency in at least one zone in the AP radiograph.

We found a relatively high level of re-surgery and complications following Agility total ankle replacement. A 7% revision rate is much higher than would be tolerated in knee or hip arthroplasty, but compares favourably to other studies of TAR. Despite radiological features which suggest loosening, the high rate of re-surgery and complications; patients are generally satisfied with the procedure, reporting lower levels of pain and improved function. Overall we feel that the Agility ankle is an acceptable alternative to ankle arthrodesis, however patients need to be warned of the risk of re-surgery.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_31 | Pages 48 - 48
1 Aug 2013
Sciberras N Patterson J MacDonald D
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Few doctors answer their bleep by stating who they are. Answering the phone in a formal manner is of utmost importance in the hospital setting especially by on-call teams who are normally referred patients by other specialties, general practitioners and in some cases by other hospitals.

An audit to evaluate the internal hospital communication was completed. In the first part of this audit, junior doctors within the orthopaedic department at the RAH were bleeped. Doctors were expected to answer by initiating the conversation by stating (1) name, (2) department, (3) grade and (4) a greeting. A list of omissions was recorded. If the call went through switchboard, it was expected that the hospital name was stated. The second part of the audit extended to other specialties in the RAH as well as orthopaedic departments in hospitals within the Greater Glasgow and Clyde health board (NHS GGC).

Forty-three bleeps were made to doctors of various grades over a period of two months. Nine bleeps (two from other hospitals) were not answered. Five doctors answered their bleep in full. Only twenty-one doctors stated their name whilst eleven stated their grade. In both instances the department was not necessarily stated. The results were similar between the different departments as well as between the seven hospitals offering an orthopaedic service within NHS GGC. Of the thirteen on-call doctors that were bleeped as an external call through switchboard, only one doctor stated the hospital name. This has implications since most hospitals within NHS GGC share a common switchboard.

These results emphasise the need for a protocol within NHS GGC for a standard etiquette for intra and inter hospital communication to ensure that patient safety and confidentiality is safeguarded.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_15 | Pages 232 - 232
1 Mar 2013
Kurtz S MacDonald D Kocagoz S Tohfafarosh M Parvizi J Klein GR Lee G Marshall A Mont M Kraay M Stulberg B Rimnac C
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Introduction

Sequentially annealed highly crosslinked polyethylenes (HXLPEs) were introduced in total knee replacement (TKR) starting in 2005 to reduce wear and particle-induced osteolysis. Few studies have reported on the clinical performance of HXLPE knees. In this study, we hypothesized that due to the reduced free radicals, sequentially annealed HXLPE would have lower oxidation levels than gamma inert-sterilized controls.

Methods

145 tibial components were retrieved at consecutive revision surgeries at 7 different surgical centers. 74 components were identified as sequentially annealed HXLPE (X3, Stryker) while the remainder (n = 71) were conventional gamma inert sterilized polyethylene. The sterilization method was confirmed by tracing the lot numbers by the manufacturer. The conventional inserts were implanted for 1.7 years (Range: 0.0–9.3 years), while the X3 components were implanted 1.1 years (Range: 0.0–4.5 years). Surface damage was assessed using the Hood method. Oxidation analysis was performed in accordance with ASTM 2102 following submersion in boiling heptane for 6 hours to remove absorbed lipids. 30 of the conventional and 29 of the HXLPE inserts were available for oxidation analysis.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_15 | Pages 108 - 108
1 Mar 2013
Higgs G Kurtz S Hanzlik J MacDonald D Kane WM Day J Klein GR Parvizi J Mont M Kraay M Martell J Gilbert J Rimnac C
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Introduction

Wear debris generation in metal-on-metal (MOM) total hip arthroplasty (THA) has emerged as a compelling issue. In the UK, clinically significant fretting corrosion was reported at head-taper junctions of MOM hip prostheses from a single manufacturer (Langton 2011). This study characterizes the prevalence of fretting and corrosion at various modular interfaces in retrieved MOM THA systems used in the United States.

Methods and Materials

106 MOM bearing systems were collected between 2003 and 2012 in an NIH-supported, multi-institutional retrieval program. From this collection, 88 modular MOM THA devices were identified, yielding 76 heads and 31 stems (22 modular necks) of 7 different bearing designs (5 manufacturers) for analysis. 10 modular CoCr acetabular liners and 5 corresponding acetabular shells were also examined. Mean age at implantation was 58 years (range, 30–85 years) and implantation time averaged 2.2 ± 1.8 years (range, 0–11.0 years). The predominant revision reason was loosening (n=52). Explants were cleaned and scored at the head taper, stem taper, proximal and distal neck tapers (for modular necks), liner, and shell interfaces in accordance with the semi-quantitative method of Goldberg et al. (2002).


The Bone & Joint Journal
Vol. 95-B, Issue 3 | Pages 360 - 366
1 Mar 2013
Clement ND MacDonald D Burnett R

We assessed the effect of mental disability on the outcome of total knee replacement (TKR) and investigated whether mental health improves post-operatively. Outcome data were prospectively recorded over a three-year period for 962 patients undergoing primary TKR for osteoarthritis. Pre-operative and one year Short-Form (SF)-12 scores and Oxford knee scores (OKS) were obtained. The mental component of the SF-12 was stratified into four groups according to level of mental disability (none ≥ 50, mild 40 to 49, moderate 30 to 39, severe < 30). Patients with any degree of mental disability had a significantly greater subjective physical disability according to the SF-12 (p = 0.06) and OKS (p < 0.001). The improvement in the disease-specific score (OKS) was not affected by a patient’s mental health (p = 0.33). In contrast, patients with mental disability had less of an improvement in their global physical health (SF-12) (p < 0.001). However, patients with any degree of mental disability had a significant improvement in their mental health post-operatively (p < 0.001).

Despite a similar improvement in their disease-specific scores and improvement in their mental health, patients with mental disability were significantly more likely to be dissatisfied with their TKR at one year (p = 0.001). Patients with poor mental health do benefit from improvements in their mental health and knee function after TKR, but also have a higher rate of dissatisfaction.

Cite this article: Bone Joint J 2013;95-B:360–6.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_15 | Pages 107 - 107
1 Mar 2013
Kurtz S MacDonald D Parvizi J Klein GR Lee G Marshall A Mont M Kraay M Stulberg B Malkani AL Rimnac C
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Introduction

The purpose of this multicenter study was to assess the oxidative stability, mechanical behavior, wear and reasons for revision of 2nd generation sequentially annealed HXLPE, X3, and compare it to 1st generation XLPE, Crossfire. We hypothesized that X3 would exhibit similar wear rates but lower oxidation than Crossfire.

Methods

182 hip liners were consecutively retrieved during revision surgeries at 7 surgical centers and continuously analyzed over the past 12 years in a prospective, multicenter study. 90 were highly crosslinked and annealed (Crossfire; Implanted 4.2±3.4 years, max: 11 years), and 92 were highly crosslinked and annealed in 3 sequential steps (X3; Implanted 1.2±1.5 years; max: 5 years). Oxidation was characterized in accordance with ASTM 2102 using transmission FTIR performed on thin sections (∼200μm) from the superior/inferior axis. Mechanical behavior was assessed via the small punch test (ASTM 2183).


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_10 | Pages 1 - 1
1 Feb 2013
Baird E Macdonald D Gilmour A Kumar C
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We reviewed the outcome of Agility total ankle replacements carried out in our institution between 2002 and 2006.

Follow-up consisted of clinical and radiological review pre-operatively, at 6 weeks, 6 and 12 months, and annually until 10 years post-op. Clinical review included the American Orthopaedic Foot and Ankle Score, satisfaction and pain scores.

30 arthroplasties were performed in 30 consecutive patients. Pre-operative diagnosis was rheumatoid arthritis (16), primary osteoarthritis (12) and post-traumatic osteoarthritis (2). After a mean follow up of 6.2 years (1.4–10.1), 4 patients had died, and 20 out of the remaining 24 were available for follow-up. Complications included lateral malleoli fracture (3), superficial peroneal nerve injury (2), one early death, unrelated to the surgical procedure, delayed syndesmotic union (1), non-union (6) and deep infection (2), of which one underwent removal of the implant; the other receives long-term oral antibiotics. AOFAS scores improved from mean 40.4 pre-op to 83.5 post-op (p<0.001). Radiological assessment revealed 25 (93%) patients had lucency in at least one zone in the AP radiograph.

We found a relatively high level of re-surgery and complications following Agility total ankle replacement. A 7% revision rate is much higher than would be tolerated in knee or hip arthroplasty, but compares favourably to other studies of TAR. Despite radiological loosening, and the high rate of re-surgery and complications; patients are generally satisfied with the procedure, reporting lower levels of pain and improved function. Overall, we feel that the Agility ankle is an acceptable alternative to arthrodesis, however patients should be warned of the risk of re-surgery


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_1 | Pages 58 - 58
1 Jan 2013
Baird E Macdonald D Gilmour A Kumar C
Full Access

We aimed to review the outcome of Agility total ankle replacements carried out in our institution between 2002 and 2006.

Follow-up consisted of clinical and radiological review pre-operatively, then at 6 weeks, 6 and 12 months, and annually until 10 years post op. Clinical review included the American Orthopaedic Foot and Ankle Score, satisfaction and pain scores. Case notes were reviewed to determine intra and post-operative complications.

30 arthroplasties were performed in 30 consecutive patients. Pre-operative diagnosis was rheumatoid arthritis(16), primary osteoarthritis(12) and post-traumatic osteoarthritis(2). After a mean follow up of 6.2 years (1.4–10.1), 4 patients had died, and 22 out of the remaining 24 were available for follow-up. Intra operative complications included lateral malleoli fracture(3) and superficial peroneal nerve injury(2). Post operative complications included 1 early death, but this was not related to the surgical procedure. Two patients developed deep infections of the prosthesis. One underwent removal of the implant; the other is on long term oral antibiotic therapy. One patient had delayed union of the syndesmosis and six patients had non-union. On clinical assessment, patients' AOFAS scores improved from mean 40.4 pre-op to 83.5 post-op (p< 0.001). Radiological assessment of the tibial component revealed 25 (93%) patients had lucency in at least one zone in the AP radiograph.

We found a relatively high level of re-surgery and complications following Agility total ankle replacement. A 7% revision rate is much higher than would be tolerated in knee or hip arthroplasty, but compares favourably to other studies of TAR. Despite radiological features which suggest loosening, the high rate of re-surgery and complications; patients are generally satisfied with the procedure, reporting lower levels of pain and improved function. Overall we feel that the Agility ankle is an acceptable alternative to ankle arthrodesis, however patients need to be warned of the risk of re-surgery.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_1 | Pages 203 - 203
1 Jan 2013
Bugler K Scott C Clement N Macdonald D Howie C Biant L
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Patient expectations and their fulfilment are an important factor in determining patient-reported outcome and satisfaction of hip (THR) and knee replacement (TKR). The aim of this prospective cohort study was to examine the expectations of patients undergoing THR and TKR, and to identify differences in expectations, predictors of high expectations and the relationship between the fulfilment of expectations and patient-reported outcome measures. During the study period, patients who underwent 346 THRs and 323 TKRs completed an expectation questionnaire, Oxford score and Short-Form 12 (SF-12) score pre-operatively. At one year post-operatively, the Oxford score, SF-12, patient satisfaction and expectation fulfilment were assessed. Univariable and multivariable analysis were performed. Improvements in mobility and daytime pain were the most important expectations in both groups. Expectation level did not differ between THR and TKR. Poor Oxford score, younger age and male gender significantly predicted high pre-operative expectations (p < 0.001). The level of pre-operative expectation was not significantly associated with the fulfilment of expectations or outcome. THR better met the expectations identified as important by patients. TKR failed to meet expectations of kneeling, squatting and stair climbing. High fulfilment of expectation in both THR and TKR was significantly predicted by young age, greater improvements in Oxford score and high pre-operative mental health scores. The fulfilment of expectations was highly correlated with satisfaction.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXVII | Pages 170 - 170
1 Sep 2012
Scott C Bhattacharya R Macdonald D Wade F Nutton R
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Unicompartmental knee replacements (UKRs) have inconsistent and variable survivorships reported in the literature. It has been suggested that many are revised for ongoing pain with no other mode of failure identified. Using a medial UKR with an all-polyethylene non-congruent tibial component from 2004–7, we noted a revision rate of 9/98 cases (9.2%) at a mean of 39 months. Subchondral sclerosis was noted under the tibial component in 3/9 revisions with well fixed implants, and the aim of this study was to investigate this as a mode of failure. 89 UKRs in 77 patients were investigated radiographically (at mean 50 months) and with SF-12 and Oxford Knee scores at mean follow up 55 months. Subjectively 23/89 cases (25%) had sclerosis under the tibial component. We describe a method of quantifying this sclerosis as a greyscale ratio (GSR), which was significantly correlated with presence/absence of sclerosis (p<0.001). Significant predictors of elevated GSR (increasing sclerosis) were female sex (p<0.001) and elevated BMI (P=0.010) on both univariate and multivariate analysis. In turn, elevated GSR was significantly associated with poorer improvement in OKS (p<0.05) at the time of final follow up. We hypothesise that this sclerosis results from repetitive microfracture and adaptive remodelling in the proximal tibia due to increased strain. Finite element analysis is required to investigate this further, but we suggest caution should be employed when considering all polyethylene UKR implants in older women and in those with BMI >35.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXIX | Pages 1 - 1
1 Jul 2012
Scott CEH Howie CR MacDonald D Biant LC
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Up to 20% of patients are not satisfied with the outcome following total knee replacement (TKR), but little is known about the predictors of this dissatisfaction. This study investigated the pre- and post-operative predictors of dissatisfaction in a large cohort of patients undergoing TKR. We assessed 1217 consecutive patients undergoing TKR between 2006 and 2008 both preoperatively and six months after surgery, using the Short-form (SF)-12 health questionnaire and the Oxford Knee Score.

Detailed co-morbidity information was also gathered. Satisfaction was measured at one year and 18.6% (226 of 1217) of patients were unsure or dissatisfied with their replacement, 81.4% (911 of 1217) were satisfied or very satisfied. Multivariate regression analysis was performed to identify independent predictors of dissatisfaction. Significant (p < 0.001) predictors of dissatisfaction at one year included the pre-operative SF-12 mental component score, the co-morbidities of depression and pain in other joints, and the six-month SF-12 score. The most significant independent predictor of dissatisfaction at 1 year was poor improvement in Oxford Knee Score pain element at 6 months. Patient expectations were highly correlated with satisfaction.

Satisfaction following TKR is multifactorial. Managing patient expectations and mental health may reduce dissatisfaction rates. However, the most significant predictor of dissatisfaction is a painful total knee replacement.


The Journal of Bone & Joint Surgery British Volume
Vol. 94-B, Issue 7 | Pages 974 - 981
1 Jul 2012
Scott CEH Bugler KE Clement ND MacDonald D Howie CR Biant LC

Patient expectations and their fulfilment are an important factor in determining patient-reported outcome and satisfaction of hip (THR) and knee replacement (TKR). The aim of this prospective cohort study was to examine the expectations of patients undergoing THR and TKR, and to identify differences in expectations, predictors of high expectations and the relationship between the fulfilment of expectations and patient-reported outcome measures. During the study period, patients who underwent 346 THRs and 323 TKRs completed an expectation questionnaire, Oxford score and Short-Form 12 (SF-12) score pre-operatively. At one year post-operatively, the Oxford score, SF-12, patient satisfaction and expectation fulfilment were assessed. Univariable and multivariable analysis were performed. Improvements in mobility and daytime pain were the most important expectations in both groups. Expectation level did not differ between THR and TKR. Poor Oxford score, younger age and male gender significantly predicted high pre-operative expectations (p < 0.001). The level of pre-operative expectation was not significantly associated with the fulfilment of expectations or outcome. THR better met the expectations identified as important by patients. TKR failed to meet expectations of kneeling, squatting and stair climbing. High fulfilment of expectation in both THR and TKR was significantly predicted by young age, greater improvements in Oxford score and high pre-operative mental health scores. The fulfilment of expectations was highly correlated with satisfaction.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXVIII | Pages 50 - 50
1 Jun 2012
Macdonald D Hands N Gislason M Macdonald E
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Systemic inflammatory conditions frequently affect both the small joints of the hand and the eye. Uveitis and scleritis is common in this group and patients are required to apply regular eye drops. Ophthalmic conditions are also common in patients with Osteoarthritis of the thumb CMCJ who have weakness and pain on pinch grip. Poor compliance with therapy due to difficulties in administering eye drops can cause permanent ocular and visual morbidity.

A laboratory based biomechanical study was performed to replicate the pinch forces applied to the 20 most frequently used eye drops. The minimum force required to disperse a drop from a full bottle held in the inverted vertical position was assessed on three occasions by placing the eye drop bottles between a finger and thumb simulator attached to a load cell. Recordings of two bottle types were repeated using 2 different ergonomic ‘aids’ produced by the pharmaceutical companies.

The data was compared to published data for pinch strength of general ophthalmology patients and to collected data for patients with thumb base CMCJ osteoarthritis.

Compressive forces varied significantly between different eye drop types from 6.4 newtons (Systane) to 20.8 newtons (Minims). The highest values were found in minims which is the most frequently used eye drop. The use of the Xalatan aid appeared to increase the force required from 7.7(+/−0.64) to 12.9 (+/−3.93) but this difference did not reach significance, p=0.08, the results for Allegan aid showed no significant difference 11.3(+/−0.91) to 9.9 (+/−1.18)p=0.17. The forces required to disperse a drop increased as the bottles became less full.

Forces required to disperse eye drops from bottles varies considerably and can be greater than the maximum pinch pressure of some patient groups which may be a cause of poor compliance. Some ergonomic aids designed to help with the application of drops do not appear to reduce the forces required.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_V | Pages 6 - 6
1 Mar 2012
Macdonald D McDonald D Siegmeth R Monaghan H Deakin A Scott N Kinninmonth A
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Patients undergoing total knee arthroplasty (TKA) experience significant postoperative pain. This impedes early mobilization and delays hospital discharge. A prospective audit of 1081 patients undergoing primary TKA during 2008 was completed. All patients followed a programme including preoperative patient education, pre-emptive analgesia, spinal/epidural anaesthesia with propofol sedation, intra-articular soft tissue wound infiltration, postoperative high volume ropivacaine boluses with an intra-articular catheter and early mobilization. Primary outcome measure was length of stay. Secondary outcomes were verbal analogue pain scores on movement, time to mobilization, nausea and vomiting scores, urinary catheterization for retention, need for rescue analgesia, range of motion at discharge and six weeks postoperatively. The median day of discharge was postoperative day four. Median pain score on mobilization was three for first postoperative night, day one and two. 35% of patients ambulated on the day of surgery and 95% of patients within 24 hours. 79% patients experienced no nausea or vomiting. Catheterization rate was 6.9%. Rescue analgesia was required in 5% of cases. The median day of discharge was postoperative day four. Median range of motion was 85° on discharge and 93° at six weeks postoperatively. This comprehensive care plan provides satisfactory postoperative analgesia allowing early safe ambulation and discharge.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_VII | Pages 8 - 8
1 Mar 2012
Oburu E Macdonald D Wilson N
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We have reviewed the complication rate over a ten year period for removal of screws placed for slipped capital femoral epiphysis (SCFE) and have surveyed the views of orthopaedic surgeons with an adult hip practice in Scotland on leaving the metalwork in situ. Whilst screw removal is favoured by many orthopaedic surgeons, a recent review of the literature reported that the complication rate for removal of implants placed for SCFE was 34%.

Between 1998 and 2007 84 patients had insertion of screws for SCFE. Of these 54 patients had screws removed, 51 of these records were available. The median duration between insertion and removal of screws was 2 yrs 7 months. Of the 51 children, overall five (9.8%) had complications - three (5.9%) major and two (3.9%) minor. Two screws could not be removed; one patient sustained a fracture after screw removal and two developed an infection.

We assessed the attitudes of adult hip surgeons on this topic using an electronic questionnaire which was completed by 29 out of 40 recipients. 78.6% of respondents support routine removal and 21.4% favour leaving the screw permanently in place. 82.2% had needed to remove metalwork from a hip requiring arthroplasty in a patient whose metalwork was inserted during childhood; and described their experience of this including the complications encountered.

We have identified a lower complication rate following screw removal inserted for SCFE than in published series. Most adult hip surgeons support routine removal once the physis is closed but studies regarding the long-term outcome of retained orthopaedic implants are needed since even with this lower complication rate the question of routine removal remains unclear.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_V | Pages 1 - 1
1 Mar 2012
Clement N MacDonald D Howie C Biant L
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There is limited literature regarding the outcome of hip and knee arthroplasty (THR and TKR) in the Super-Elderly (≥80yrs). The aim is to compare the outcome of THR and TKR in the Super-Elderly with a standard-age cohort of patients. From January 2006 to August 2008; 1290 TKR and 1344 THR were performed at the study institute. Comorbidity, length of stay, patient satisfaction, Oxford knee or hip scores, and SF12 scores were recorded prospectively. The Oxford Score and SF12 were recorded at one year. The mode age range was 65-74yrs for TKR (n=492) and THR (n=495), deemed the standard cohort. 185 TKR and 171 THR were performed in the Super-Elderly. Outcome in this cohort was compared to the standard.

The standard cohort had a greater absolute improvement in Oxford knee scores (15.8 and 14.7.p=0.2). Improvement of absolute Oxford hip scores revealed no difference (20.0 and 20.2.p=0.8), but the Super-Elderly had a greater improvement in pain components (11.0 vs.12.0.p=0.05) with a lesser improvement of the functional components (9.0.vs.8.2.p=0.05). There was a greater improvement in the physical component of the SF-12 score in the standard cohort for both TKR and THR (10.6.vs.7.9.p=0.05 and 14.4.vs.10.4.p=<0.01, respectively).

No significant difference was seen in comorbidities, but the Super-Elderly patients had a longer hospital stay for TKR (6.2.vs.8.3.p=0.01) and THR (5.9.vs.9.0.p=0.01).

The Super-Elderly were more satisfied with their surgery (p=0.05).

Super-Elderly patients have comparable outcomes to their younger counterparts and are more satisfied with their surgery, but they may require a longer length of stay.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_II | Pages 67 - 67
1 Feb 2012
Pike H Macdonald D Tyreman N
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Infection of total hip replacement is a disaster, with a quoted incidence of 1-2%. Anecdotal evidence has led many to believe that aggressive management of early infection following hip replacement can prevent failure. As yet, there is no firm evidence. We have reviewed 20 consecutive cases of early infection (<6 weeks post-op) treated by open debridement and washout.

The cases were 19 total hip replacements and 1 hemiarthroplasty. All had prolonged wound I discharge and elevated inflammatory parameters. No differentiation was made between superficial and deep infections because at this stage the deep fascia had not yet healed. 13 cases had positive cultures (6 staphylococcus, 5 coagulase negative staphylococcus, 1 coliform, 1 streptococcus). 7 cases had either negative cultures or mixed growth, but were clinically infected. Intravenous antibiotics were given after debridement until the wound healed.

Thirteen (65%) were clinically and radiologically free of infection at a minimum of 1 year follow-up. Failure to eradicate infection was treated by revision surgery and this was performed in 4 patients. Of the remaining 3 patients, one underwent excision arthroplasty, one was infected but refused surgery and one was infected but medically unfit for surgery. There is no control group, but it would be ethically very difficult to organise. As expected, we had small numbers and a mixed collection of organisms, so statistical comparisons are limited.

In conclusion, these patients represent a very high risk of ongoing infection. 13 hips (65%) had no evidence of ongoing infection at a minimum of 1 year follow up. This study supports aggressive surgical management of early infection following hip replacements. Eradication of early infection can be achieved without removal of the implant.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_II | Pages 92 - 92
1 Feb 2012
Giannoudis P Allami M Harwood P Macdonald D Dimitriou R Pape H Krettek C
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We aimed to investigate the treatment and outcome of patients over 65 years of age with tibial Pilon fracture. Patients were treated by primary open reduction and internal fixation or external fixation (EF) as determined by local soft tissue conditions. Patient course, incidence of radiological osteoarthritis and functional outcome using the SF-36 questionnaire were recorded. All patients were evaluated serially until discharge from final follow-up. The mean follow-up time was 28 months (12-45). Statistical analysis was performed using Analyse-it(tm) software for Excel.

In total 25 patients were studied. Two patients died before completion of treatment and were excluded from the final analysis. Therefore, 23 patients (10 male) were included with a mean age of 70.9 years (range 66-89) and a mean ISS of 10.25 (range 9-22). There were 4 grade IIIb open injuries.

Three patients suffered superficial tibial wound infection. Two patients underwent early secondary amputation due to deep bone sepsis within 8 weeks of injury. One patient in the ORIF group underwent primary arthrodesis, which was subsequently revised due to non-union. 3 patients underwent secondary bone grafting to enhance healing, performed at 2, 6 and 9 weeks. 2 patients with metal work failure underwent subsequent revision of ORIF and progressed to union; the mean time to union was 33.8 weeks. At final follow-up 7 (28%) patients had radiological features of osteoarthritis but none had symptoms severe enough to warrant ankle arthrodesis. There were significant differences from the USA norm in physical function score, role physical score, and physical component score, (p< 0.01).

Conclusion/Significance

In older patients local complications are relatively common and clinical vigilance must be maintained in order to allow appropriate intervention during their post-operative course. Despite the incidence of radiological post-traumatic arthrosis, none of the patients progressed to ankle fusion.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_II | Pages 93 - 93
1 Feb 2012
Giannoudis P Raman R Harwood P Allami M Dimitriou R Macdonald D Kind P
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We aimed to quantify the health related quality of life in a series of patients suffering a variety of different tibial injuries. Patients with previous tibial injury, randomly selected from our trauma database, who successfully completed their entire course of treatment at our institution, were recalled for final assessment. Mean time to final follow-up was 37.4 months. Statistical analysis was performed using SPSS computer software.

Overall, 130 patients were evaluated. There was no significant difference in the self-care dimension between the groups. Psychological problems were common in patients with IIIb and IIIc fractures, as well as amputees, with the highest incidence in those with IIIc fractures. Patients who had undergone amputation and those with IIIb open fractures reported problems with mobility significantly more frequently than those who had IIIc type injuries. However, this could be partially attributed to the significant difference in mean age between groups, with patients sustaining IIIc injuries being younger (31.9 vs 46.9). Patients with IIIb and IIIc type fractures reported significantly more problems with pain compared with those who had undergone amputation. Interestingly, patients who had undergone fasciotomy reported pain as frequently as amputees. Regarding the VAS, only patients with closed fractures reported significantly different scores from the mean of all the other groups.

These data represent the health related quality of life of patients having suffered the full spectrum of tibial injury and should be considered when determining the treatment options for these patients.


The Journal of Bone & Joint Surgery British Volume
Vol. 93-B, Issue 9 | Pages 1265 - 1270
1 Sep 2011
Clement ND MacDonald D Howie CR Biant LC

Primary arthroplasty may be denied to very elderly patients based upon the perceived outcome and risks associated with surgery. This prospective study compared the outcome, complications, and mortality of total hip (TKR) and total knee replacement (TKR) in a prospectively selected group of patients aged ≥ 80 years with that of a control group aged between 65 and 74 years. There were 171 and 495 THRs and 185 and 492 TKRs performed in the older and control groups, respectively. No significant difference was observed in the mean improvement of Oxford hip and knee scores between the groups at 12 months (0.98, (95% confidence interval (CI) −0.66 to 2.95), p = 0.34 and 1.15 (95% CI −0.65 to 2.94), p = 0.16, respectively). The control group had a significantly (p = 0.02 and p = 0.04, respectively) greater improvement in the physical well being component of their SF-12 score, but the older group was more satisfied with their THR (p = 0.047). The older group had a longer hospital stay for both THR (5.9 versus 9.0 days, p < 0.0001) and TKR (6.2 versus 8.3 days, p < 0.0001). The rates of post-operative complications and mortality were increased in the older group.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_III | Pages 303 - 303
1 Jul 2011
Macdonald D Macdonald E Perry S
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Introduction: The health benefits of physical exercise are well recognised. In recent years the department of health has been encouraging the UK population to exercise more. We aimed to determine if there was any change in the number and pattern of sport and exercise related injuries attending a city Emergency Department (ED) over the past two decades.

Methods: We undertook a prospective comparative study of patients attending an ED over two time periods: Aug 85 – April 86 and Aug 04 – April 05. All identified patients had a standardised proforma inserted into their notes which was prospectively completed by the attending clinician at the time of consultation.

Results: We observed a 35% increase in sporting injuries over the 19 year period (1000 injuries out of 37036 new patients vs 1351 out of 37526, p< 0.0001). The total number of new patients attending the ED remained unchanged during this time. Males remain the majority of patients with sports injuries (86%). We noted a change in age distribution with a relative increase in patients under 16 yrs (p< 0.0001), a decrease in 16–24 yrs (p=0.0002) and an increase in patients over 40yrs (p< 0.001). There was a significant reduction in patients presenting out of hours and a significant increase in the delay to presenting at ED with the majority of patients presenting over 4 hours after the injury. Football remains the commonest cause of sports injury accounting for half of all sports injuries, followed by rugby but there has been a relative decline in skiing, martial arts jogging and squash as a cause of injury and a significant increase in injuries due to snowboarding, skateboarding and basketball.

Conclusion: There has been an increase in the number of sports injuries attending hospital, which may represent a general increase in sport and exercise participation among our population.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_III | Pages 387 - 387
1 Jul 2011
Macdonald D Clarke J Kinninmonth A
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Computer-assisted surgical techniques in knee replacement procedures have been shown to increase the accuracy of implant positioning and reduce the incidence of alignment and soft-tissue balancing “outliers”. The use of this technology as a training tool is less widely reported. However, the recent implementation of the EWTD 48-hour working week for junior doctors has focussed attention on the issues of surgical training and experience. Recent evidence from trainee logbooks has shown a significant downward trend in operative exposure and this is forcing changes in the principles of how training should be delivered. Trainees are actively required to demonstrate operative competence in order to progress but are increasingly faced with limited opportunities to acquire these skills. On the other hand, trainers also face difficulties with the prospect of supervising less accomplished trainees which raises ethical issues of patient protection. We present a trainee’s perspective of experience gained in a unit routinely using computer-assisted technology and highlight the potential to enhance the learning process.

Navigation systems provide constant visual and numerical feedback via a computer simulated interpretation. Initially this displays relevant functional anatomy, helps in the identification of anatomical landmarks and demonstrates sagittal and coronal plane deformities which can be difficult to accurately assess “by eye”. Computer-assisted systems have the benefit of displaying only bony anatomy which improves visualisation. This can then be compared to the palpable, clinical deformity on the table. The geometry of the native knee is also made clear with the navigation system leading to a better understand of the objectives of TKR. There are some aspects of the biomechanics of the knee which are difficult to appreciate, such as the changes in varus-valgus alignment during flexion and extension. This may be very subtle and difficult to pick up manually but can look quite dramatic on the computer.

The position of cutting jigs which are held to the bone by pins can be altered by inadvertently lifting or hanging on them with the saw, when making the bone cuts. Additionally the cut can be altered by advancing the cutting block closer to the bone, for example if cutting the tibia with a posterior slope. Both these effects can be quantified by using the navigation tools to confirm the cut that has been made. Trainers can have the benefit of seeing the alignment and confirming the cuts made by a trainee without having to get closely involved with the operation. Cementation technique is also open to scrutiny with the ability to compare pre and post cementation alignment.

The positive feedback obtained from computer assisted surgery is educational to the trainee, by giving an undisputable computer generated graphic of what they are doing during the different stages of total knee arthroplasty. It also shows what has been achieved at the end of the procedure. This can give both the trainer and trainee more confidence in the procedure and ensures patient safety.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_II | Pages 147 - 148
1 May 2011
Ohly N Gunner C Macdonald D Breusch S
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Introduction: Foot and ankle involvement in rheumatoid arthritis is common. Pain and disability secondary to planovalgus deformity and the arthritic process are difficult to control with conservative measures. Arthroplasty of the ankle is associated with high failure rates and does not completely correct the deformity. Arthrodesis of the hindfoot is a good option to alleviate pain, correct the deformity and improve functional ability, however has not been well reported in the literature.

Aims: To determine change in quantitative measures of patient health, pain and functional ability following hindfoot arthrodesis in patients with rheumatoid arthritis, and to assess patient satisfaction postoperatively.

Methods: 24 consecutive additive hindfoot arthrodeses were performed by a single surgeon on 22 patients with rheumatoid arthritis. Patients were assessed preoperatively using the Short Form-12 Health Survey (SF-12), Manchester-Oxford Foot Questionnaire (MOXFQ) and pain scores. These assessments were repeated at 6 and 12 months postoperatively, with an additional satisfaction questionnaire.

Results: There was a marked and sustained improvement in the post-operative SF-12, MOXFQ and pain scores, with 71% of patients reporting no pain at 12 months. 19 out of 22 patients reported being satisfied or very satisfied with the operation. Bony union was achieved in all patients, both on clinical and radiological criteria. Most patients returned to normal footwear, some with slight modification to facilitate a more normal gait cycle.

Conclusions: This study shows that additive hindfoot arthrodesis can be a very effective procedure in the management of moderate to severe ankle and hind-foot disease in rheumatoid arthritis. Patients should be counselled regarding the considerable recovery period; however significant improvement in the patient’s general health, foot function and pain can be expected.


The Journal of Bone & Joint Surgery British Volume
Vol. 93-B, Issue 4 | Pages 464 - 469
1 Apr 2011
Clement ND Muzammil A MacDonald D Howie CR Biant LC

This prospective study assessed the effect of social deprivation on the Oxford hip score at one year after total hip replacement. An analysis of 1312 patients undergoing 1359 primary total hip replacements for symptomatic osteoarthritis was performed over a 35-month period. Social deprivation was assessed using the Carstairs index. Those patients who were most deprived underwent surgery at an earlier age (p = 0.04), had more comorbidities (p = 0.02), increased severity of symptoms at presentation (p = 0.001), and were not as satisfied with their outcome (p = 0.03) compared with more affluent patients. There was a significant improvement in Oxford scores at 12 months relative to pre-operative scores for all socioeconomic categories (p < 0.001). Social deprivation was a significant independent predictor of mean improvement in Oxford scores at 12 months, after adjusting for confounding variables (p = 0.001). Deprivation was also associated with an increased risk of dislocation (odds ratio 5.3, p < 0.001) and mortality at 90 days (odds ratio 3.2, p = 0.02).

Outcome, risk of dislocation and early mortality after a total hip replacement are affected by the socioeconomic status of the patient


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_I | Pages 62 - 62
1 Jan 2011
Augustine A Macdonald D Murray H Badesha J Mohammed A Meek R Patil S
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Infection following hip arthroplasty although uncommon can have devastating outcomes. Obesity, defined as a BMI of ≥ 30, is a risk factor for infection in this population. Coagulase negative staphylococcus aureus (CNS) is the commonest causative organism isolated from infected arthroplasties. This study was performed to determine if there has been a change in the causative organisms isolated from infected hip arthroplasties and to see if there is a difference in obese patients.

Data on all deep infection following primary and revision hips was obtained from the surgical site infection register from April 1998 to Nov 2007. Case notes were reviewed retrospectively. There were 49 patients with 51 infected arthroplasties; 25 infected Primary THAs and 26 infected Revision THAs. We found a female preponderance in the infected primary and revision THAs (n=30). 63.2% of all patients had a BMI of ≥ 30, compared to only 34.7% of the non infected population (p< 0.0001). Over the period studied, CNS was the most common organism isolated (56.8%) followed by mixed organisms (37.2%) and staphylococcus aureus (25.4%). Multiple organisms were found exclusively in obese patients. In more than half of cases the causative organisms were resistant to more than two antibiotics.

This study shows that over the last 10 years, CNS continues to be the most frequently isolated organism in infected hip arthroplasties. Multiple organisms with multiple antibiotic resistances are common in obese patients. On this basis we recommend that combination antibiotic therapy should be considered in obese patients.


The Journal of Bone & Joint Surgery British Volume
Vol. 92-B, Issue 9 | Pages 1253 - 1258
1 Sep 2010
Scott CEH Howie CR MacDonald D Biant LC

Up to 20% of patients are not satisfied with the outcome following total knee replacement (TKR). This study investigated the pre- and post-operative predictors of dissatisfaction in a large cohort of patients undergoing TKR. We assessed 1217 consecutive patients between 2006 and 2008 both before operation and six months after, using the Short-form (SF)-12 health questionnaire and the Oxford Knee Score. Detailed information concerning comorbidity was also gathered. Satisfaction was measured at one year when 18.6% (226 of 1217) of patients were unsure or dissatisfied with their replacement and 81.4% (911 of 1217) were satisfied or very satisfied. Multivariate regression analysis was performed to identify independent predictors of dissatisfaction. Significant (p < 0.001) predictors at one year included the pre-operative SF-12 mental component score, depression and pain in other joints, the six-month SF-12 score and poorer improvement in the pain element of the Oxford Knee Score.

Patient expectations were highly correlated with satisfaction. Satisfaction following TKR is multifactorial. Managing the expectations and mental health of the patients may reduce dissatisfaction. However, the most significant predictor of dissatisfaction is a painful total knee replacement.


The Journal of Bone & Joint Surgery British Volume
Vol. 92-B, Issue 8 | Pages 1112 - 1117
1 Aug 2010
Clement ND Hallett A MacDonald D Howie C McBirnie J

We compared the outcome of arthroscopic repair of the rotator cuff in 32 diabetic patients with the outcome in 32 non-diabetic patients matched for age, gender, size of tear and comorbidities. The Constant-Murley score improved from a mean of 49.2 (24 to 80) pre-operatively to 60.8 (34 to 95) post-operatively (p = 0.0006) in the diabetic patients, and from 46.4 (23 to 90) pre-operatively to 65.2 (25 to 100) post-operatively (p = 0.0003) in the non-diabetic patients at six months. This was significantly greater (p = 0.0002) in non-diabetic patients (18.8) than in diabetics (11.6). There was no significant change in the mean mental component of the Short-Form 12, but the mean physical component increased from 35 to 41 in non-diabetics (p = 0.0001), and from 37 to 39 (p = 0.15) in diabetics. These trends were observed at one year.

Patients with diabetes showed improvement of pain and function following arthroscopic rotator cuff repair in the short term, but less than their non-diabetic counterparts.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_III | Pages 387 - 388
1 Jul 2010
Augustine A Macdonald D Murray HM Mohammed A Meek R Patil S
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Introduction: Infection following hip arthroplasty although uncommon can have devastating outcomes. Obesity, defined as a BMI of ≥ 30, is a known risk factor for infection in this population. Coagulase negative Staph Aureus (CNS) is the commonest causative organism isolated from infected arthroplasties. This study was performed to determine if there has been a change in the causative organisms isolated from infected hip arthroplasties and to see if there is a difference in obese patients.

Methods: Data on all deep infection following primary and revision hips was obtained from the surgical site infection register from April 1998 to November 2007. All case notes were reviewed retrospectively.

Results: There were 49 patients with 51 infected arthroplasties; 25 infected Primary THAs and 26 infected Revision THAs. We found a female preponderance in the infected primary and revision THAs (n=30). 65.3% of all patients had a BMI of ≥ 30. Over the period studied, Coagulase negative Staph was the most common organism isolated (56.8%) followed by mixed organisms (37.2%) and Staph Aureus (25.4%). Multiple organisms were found exclusively in obese patients. In more than half of cases the causative organisms were resistant to ≥ 2 antibiotics.

Discussion: This study shows that over the last 10 years, CNS continues to be the most frequently isolated organism in infected hip arthroplasties. Multiple organisms with multiple antibiotic resistances are common in obese patients. On this basis we recommend that combination antibiotic therapy should be considered in obese patients.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_III | Pages 402 - 402
1 Jul 2010
Demosthenous N MacDonald D Simpson A
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Introduction: Limb lengthening with external fixators has been associated with many complications including pin tract infections, damage to neurovascular structures, joint stiffness, delayed consolidation, and pain. These can lead to a detrimental functional outcome and psychological upset with a consequent negative impact on patients’ quality of life. The Intramedullary Skeletal Kinetic Distractor (ISKD) is a fully implantable device that may offer a better functional and psychological outcome. The aim of this study therefore was to evaluate the functional and psychological outcome in a series of patients undergoing femoral lengthening with the ISKD.

Methods: Twenty patients underwent intramedullary lengthening via ISKD. Eighteen of these had lost femoral bone length secondary to trauma, and two were affected by congenital limb shortening (one had both femora lengthened at different time intervals). Patients completed Toronto Extremity Salvation Score (TESS) (to evaluate subjective physical disability), and Short Form 36 (SF36) questionnaires pre and post-operatively.

Results: Patients’ post operative TESS scores demonstrated a significant improvement in patient perception of their physical disability. SF36 responses after surgery improved in several areas including physical functioning, role limitation due to emotional problems, social functioning, mental health, pain experienced and change in health; the greatest improvements seen in role limitation due to emotional problem, social functioning, mental health, pain, and change in health.

Discussion: These results indicate that limb lengthening with the ISKD improves patients’ overall quality of life decreasing post operative pain, improving their social functioning and mental health, overall ISKD lengthening improves how the patients perceive their health and physical disability.


Orthopaedic Proceedings
Vol. 90-B, Issue SUPP_II | Pages 229 - 229
1 Jul 2008
MacDonald D Holt G Vass K Marsh A Kumar S
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Lumps of the foot present relatively infrequently to the orthopaedic service. There have been very few published studies looking at presenting characteristics or the differential diagnosis of such lesions. We report our experience of foot lumps treated surgically looking at the patient demographics, presenting characteristics, diagnoses encountered and the diagnostic accuracy of the surgeon. All patients who underwent excision or biopsy of a foot lump over a period of 4 years were studied; 101 patients were identified. Average age was 47.3 years (range 14–79); there was a significant female preponderance with 73 females and 28 males (p< 0.0001). Pain was the single most common presenting complaint followed by footwear problems. Only three patients attended because of cosmetic reasons and neurological symptoms were very rare with only one patient complaining of paraesthesia. Certain lesions were more commonly encountered in specific zones of the foot. 32 different histological types were identified, ganglion cysts were the most commonly encountered lesions and there was only one malignant lesion encountered in this study. Only 58 out of the l01 lumps were correctly diagnosed prior to surgery.

We have shown that there are a wide variety of potential diagnoses, which have to be considered when examining a patient with a foot lump. There is a low diagnostic accuracy for foot lumps and therefore surgical excision and histological diagnosis should be sought if there is any uncertainty.


The Journal of Bone & Joint Surgery British Volume
Vol. 88-B, Issue 8 | Pages 1060 - 1064
1 Aug 2006
Holt G Macdonald D Fraser M Reece AT

Despite the increase in numbers of the extreme elderly, little data is available regarding their outcome after surgery for fracture of the hip. We performed a prospective study of 50 patients aged 95 years and over who underwent this procedure. Outcome measures included morbidity, mortality, hospital stay, residential and walking status. Comparison was made with a control group of 200 consecutive patients aged less than 95 years who had a similar operation. The mortality at 28 and 120 days was higher (p = 0.005, p = 0.001) in the patients over 95 years. However, the one-year cumulative post-operative mortality was neither significantly different between the two groups (p = 0.229) nor from the standardised mortality rate for the age-matched population (p = 0.445). Predictors of mortality included the ASA grade, the number of comorbid medical conditions and active medical problems on admission. Patients over 95 were unlikely to recover their independence and at a mean follow-up of 29.3 months (12.1 to 48) 96% required permanent institutional care.


Orthopaedic Proceedings
Vol. 88-B, Issue SUPP_II | Pages 249 - 249
1 May 2006
Gordon A Southam L Loughlin J Stockley I Hamer A Macdonald D Eastell R Wilkinson M
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In-vitro evidence suggests that wear debris can alter osteoblast function resulting in decreased bone matrix production and negative remodelling balance. FRZB encodes for Secreted Frizzled-Related Protein 3 which may play a role in bone formation and osteoarthritis. This study was undertaken to investigate whether the recently described single nucleotide polymorphisms (SNPs) at positions [+6] and [+109] of the FRZB gene are associated with osteolysis after THA.

Genomic DNA was extracted from 481 North European Caucasians at a mean of 12 years following cemented THA for idiopathic osteoarthritis. The control group consisted of 267 subjects and the osteolysis group 214 subjects. The [+6] and [+109] FRZB SNPs were genotyped using standard techniques.

For the FRZB [+6] SNP, the rare T allele was significantly over-represented in control versus the osteolysis group (χ2 test for trend, p=0.02,). The odds ratio for osteolysis associated with carriage of the [+6] T-allele versus the [+6] C-allele was 0.58 (95%CI 0.36 to 0.94), p=0.03. The odds ratio for osteolysis associated with carriage of the [+109] G-allele versus the [+109] C-allele was 0.66 (0.38 to 1.12), p=0.15. A number of covariates have previously been described in this cohort and after adjustment for the effects of these covariates, the odds ratio for osteolysis with carriage of the [+6] T-allele was 0.69 (0.42–1.16).

We found that the FRZB [+6] T-allele is less common in subjects with osteolysis after THA versus controls, suggesting that allelic variants of genes associated with bone formation pathways may have a role in modulating the risk of osteolysis. However its loss of significance after correction for other factors suggests an interaction between this allele and other risk factors in osteolysis.


Orthopaedic Proceedings
Vol. 88-B, Issue SUPP_II | Pages 276 - 276
1 May 2006
Stewart D Macdonald D Leach W
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We performed a prospective audit to assess radiological and clinical sequelae of using injectable calcium sulphate in the management of distal radial fractures.

All patients in a 4-month period who were treated with injectable calcium sulphate for distal radial fracture were included in the audit. Initial data was collected on demographics; AO classification and degree of deformity; method of fixation and surgical complications. Follow up consisted of clinical and radiological assessment of fracture healing at standard fracture clinic intervals with a final assessment of subjective functional recovery. 16 patients were included in the audit, all of whom were followed up for a minimum of 8 weeks. We observed a low incidence of secondary displacement, and did not observe the problem of increased pain and erythema that has been observed with other bone graft substitutes.

We conclude that injectable calcium sulphate is a useful adjunct to conventional management of these fractures that is safe, helps maintain fracture reduction and is not associated with product specific complications.


Orthopaedic Proceedings
Vol. 87-B, Issue SUPP_III | Pages 339 - 339
1 Sep 2005
MacDonald S Rorabeck C Marr J Clark C Swafford J Macdonald D
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Introduction and Aims: The dilemma to retain or sacrifice the posterior cruciate ligament in a primary total knee arthroplasty continues to be an area of discussion. A randomised clinical trial was performed comparing clinical, radiographic and quality of life outcomes between patients receiving a posterior cruciate sparing versus posterior cruciate substituting knee implants.

Method: A multi-centred, prospective, randomised, blinded, clinical trial was performed to compare posterior cruciate retaining (CR) versus posterior cruciate substitution (PS) in osteoarthritic patients with an intact posterior cruciate ligament, undergoing total knee arthroplasty using the AMK® (Depuy®, Warsaw, Indiana) component. One hundred and fifty-two patients were randomised to receive one of the two devices. Patients were evaluated pre-operatively, at three, six, 12 months and annually thereafter. Patient demographics, radiographs, and multiple validated, outcome measures (WOMAC, SF-12, the Knee Society Clinical Rating System, and a stair climbing test) were evaluated. Patients and assessors were blinded to the implant design.

Results: One hundred and fifty-two patients were randomised at three centres; 72 in the CR group and 80 in the PS group. One patient was revised due to instability. Average follow-up was 5.14 years (range 2.97–6.99 years). There were no significant differences in baseline patient demographics between groups. There were no significant differences in outcome measures or radiographic findings. There were no significant differences in the Knee Society Clinical Rating System (CR- 159.18 versus PS- 156.49). There were no differences in knee extension at latest follow-up (CR- 1.02) and (PS- 1.10). There were no differences in knee flexion at latest follow-up (CR-111.00 ) and (PS- 113.61). No differences were noted in the WOMAC and SF-12 scores between the two groups.

Conclusion: In this prospective randomised clinical trial no significant differences involving radiographs and multiple outcome measures could be seen between a cruciate retaining versus a posterior stabilised total knee prostheses at a mean follow-up of 5.14 years. Long-term evaluation is necessary to comment on wear, osteolysis and implant longevity.


Orthopaedic Proceedings
Vol. 86-B, Issue SUPP_III | Pages 363 - 363
1 Mar 2004
Venkateswaran B Rawes M Deacon P Macdonald D
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Aims: Prosthesis malpositioning and inadequate cement mantles have been shown to adversely affect outcomes in cemented total hip arthroplasty. Although this has been extensively studied and reported for anteroposterior (AP) radiographs, we have found a paucity of literature concerning lateral radiographs which this study addresses. Methods: We analysed radiographs of 100 patients (Group I) with cemented Charnley total hip replacements (52 ßanged, 48 round back) performed through the lateral approach to determine the relationship between stem positioning and cement mantles in both AP and lateral radiographs. The measurements were made by a single observer and the data was analysed using chi squared tests to compare categorical data. Results: The most common stem malpositioning was seen in the lateral radiographs with þfty þve percent of stems directed 4 or more degrees from anterior to posterior (A to P). In contrast on the AP radiographs 18% of stems were directed from medial to lateral (Varus) and 3% of stems were directed from lateral to medial (Valgus) 4 or more degrees. There was no relationship between the different malpositions. Adequate resection of the posterior femoral neck gave better alignment of the stem in the lateral radiograph (p< 0.001). The ßanged stems were signiþcantly more in varus as compared to round back stems (p< 0.01). Cement mantles were most often deþcient in Gruen zone 12. There was a strong association between sagittal malpositioning and deþcient zones 12 and 9 (p< 0.001). Conclusions: This study demonstrates that sagittal mal-positioning of the stem is most important and surgical technique has a signiþcant inßuence on the same.


Orthopaedic Proceedings
Vol. 86-B, Issue SUPP_III | Pages 335 - 335
1 Mar 2004
Raman R Matthews S Macdonald D Smith R Giannoudis P
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Aim: We have reviewed the patients treated in our institution with vertical shear fractures of the pelvis and report on our treatment protocol and long term functional outcome. Methods: Between Jan 1993 and Jan 2002 patients with vertical shear fractures were identiþed. Data such as age, sex, aetiology, associated injuries, ISS, resuscitation requirements, transfusion requirements, ICU/HDU stay, treatment, urological injuries, systemic complications, neurological injury and mortality were recorded and analysed. Functional outcome assessment was performed using the following generic tools: Euro-qol 5D (EQ), SF36 v2 (Short form), SMFA, Majeed score and VAS. Results: Out of 380 pelvic ring injuries we identiþed 31 vertical shear fractures in 29 consecutive patients (4 female). The median ISS Score was 22. Motorcycle accidents were responsible for 27%. Injuries were identiþed in the chest (12 patients), abdomen (8 patients) and extremities (14 patients). Urethral injury was present in 9 patients. Ruptured viscus was identiþed in 3 cases. At presentation neurologic deþcit was present in 9 cases. Posterior ring was stabilised in 3(0–13) days. Systemic complications developed in 6 patients Ð ARDS in 4 patients and sepsis in 2 (6%). The mean follow up was 39 months. Functional outcome using the Majeed score revealed that 1/3 of the patients did fair. TheSF-36 v2 analysis, EQ 5-D revealed a moderate functional outcome. The SMFA and the visual analogue score also revealed similar outcomes. Conclusions: Prompt resuscitation and early temporarily stabilisation of the pelvic ring is essential. Sound reconstruction of the pelvic ring is not always associated with good results probably due to the extensive pelvic ßoor trauma as seen in this series of patients. Younger individuals seem to have a relatively better outcome when compared to the older age group.


Orthopaedic Proceedings
Vol. 85-B, Issue SUPP_II | Pages 171 - 171
1 Feb 2003
Kalap N Macdonald D Matthews S Giannoudis P
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The purpose of this study was to investigate the validity of exchange intramedullary nailing for the treatment of infected tibial non-union.

14 (10 male) patients with tibial fractures were treated in our institution with exchange nailing for infected tibial non-union. The mean age of the patients was 34.3 years (range 18–60) and the mean ISS was 17.5 (range 9–57). Seven fractures were originally open (grade IIIb). All patients had clinical and radiological evidence of non-union and in each case there was clinical and microbiological evidence of intramedullary infection. Following initial stabilisation, all the patients subsequently had an exchange intramedullary nail performed together with debridement and antibiotics. The mean time between original nailing and exchange nailing was 28 weeks. Antibiotics were then continued for a minimal period of 6 weeks, or longer as the clinical situation warranted. The average length of follow-up was 24 months following exchange nailing.

There were 7 positive cultures of MRSA, 4 of staph. aureus and in 3 cases multiple bacteria were grown from the samples. No further treatment was required following exchange nailing in 5/14 (35.7%) cases. 4 patients required further soft tissue debridement and a free flap to secure union. Of the remaining 5 patients, 1 required dynamisation, another required incision and drainage of peri-fracture abscess, the third patient needed iliac crest bone grafting which eventually resulted in union. The penultimate patient had numerous operations after the exchange nailing before finally uniting with bone morphogenic protein. Unfortunately the last patient developed overwhelming sepsis which necessitated below knee amputation. Overall, the mean time to union was 11.3 months (4–24).

In this series of patients the success rate of exchange nailing for septic tibial pseudarthrosis was 78.5% (11/14). We believe that exchange tibial nailing remains an effective method of treatment in the presence of deep bone sepsis.


The Journal of Bone & Joint Surgery British Volume
Vol. 71-B, Issue 3 | Pages 539 - 539
1 May 1989
Bransby-Zachary M MacDonald D Singh I Newman R


The Journal of Bone & Joint Surgery British Volume
Vol. 71-B, Issue 2 | Pages 296 - 299
1 Mar 1989
Macdonald D Hutton J Kelly I

We assessed patellofemoral joint function by combining the measurement of maximal isometric extensor torque at the knee with clinical and radiological measurements in order to calculate the patellofemoral contact force. Eighteen volunteers established the normal ranges of results and the reliability of the system. Of the 39 patients with a variety of knee problems, 29 had anterior knee pain, and all had a subsequent arthroscopy. Patients with anterior knee pain and lesions in the patellar cartilage had significantly reduced isometric contact forces, but those with normal patellofemoral cartilage had normal contact forces. Our method may be useful in providing an objective assessment of anterior knee pain and a quantitative means of monitoring its treatment.


The Journal of Bone & Joint Surgery British Volume
Vol. 70-B, Issue 2 | Pages 319 - 321
1 Mar 1988
Carr A Macdonald D Waterhouse N

The use of an osteocutaneous free fibular graft as a single-stage reconstructive procedure for composite tissue loss is increasingly common. Detailed anatomical study in cadavers of the blood supply to the graft demonstrates cutaneous arteries arising from the peroneal artery and then passing along the posterior surface of the lateral intermuscular septum. These vessels pierce the crural fascia and then ramify to supply the skin. Knowledge of the vascular anatomy of the skin overlying the fibula is essential to the success of the graft.