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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).


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_1 | Pages 58 - 58
1 Jan 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_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_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.