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Bone & Joint Open
Vol. 4, Issue 10 | Pages 782 - 790
18 Oct 2023
Hamilton DF Gaston P Macpherson GJ Simpson P Clement ND

Aims

The primary aim of this study is to assess the survival of the uncemented hydroxyapatite (HA) coated Trident II acetabular component as part of a hybrid total hip arthroplasty (THA) using a cemented Exeter stem. The secondary aims are to assess the complications, joint-specific function, health-related quality of life, and radiological signs of loosening of the acetabular component.

Methods

A single-centre, prospective cohort study of 125 implants will be undertaken. Patients undergoing hybrid THA at the study centre will be recruited. Inclusion criteria are patients suitable for the use of the uncemented acetabular component, aged 18 to 75 years, willing and able to comply with the study protocol, and provide informed consent. Exclusion criteria includes patients not meeting study inclusion criteria, inadequate bone stock to support fixation of the prosthesis, a BMI > 40 kg/m2, or THA performed for pain relief in those with severely restricted mobility.


Bone & Joint Research
Vol. 10, Issue 1 | Pages 22 - 30
1 Jan 2021
Clement ND Gaston P Bell A Simpson P Macpherson G Hamilton DF Patton JT

Aims

The primary aim of this study was to compare the hip-specific functional outcome of robotic assisted total hip arthroplasty (rTHA) with manual total hip arthroplasty (mTHA) in patients with osteoarthritis (OA). Secondary aims were to compare general health improvement, patient satisfaction, and radiological component position and restoration of leg length between rTHA and mTHA.

Methods

A total of 40 patients undergoing rTHA were propensity score matched to 80 patients undergoing mTHA for OA. Patients were matched for age, sex, and preoperative function. The Oxford Hip Score (OHS), Forgotten Joint Score (FJS), and EuroQol five-dimension questionnaire (EQ-5D) were collected pre- and postoperatively (mean 10 months (SD 2.2) in rTHA group and 12 months (SD 0.3) in mTHA group). In addition, patient satisfaction was collected postoperatively. Component accuracy was assessed using Lewinnek and Callanan safe zones, and restoration of leg length were assessed radiologically.


Bone & Joint Research
Vol. 9, Issue 1 | Pages 15 - 22
1 Jan 2020
Clement ND Bell A Simpson P Macpherson G Patton JT Hamilton DF

Aims

The primary aim of the study was to compare the knee-specific functional outcome of robotic unicompartmental knee arthroplasty (rUKA) with manual total knee arthroplasty (mTKA) for the management of isolated medial compartment osteoarthritis. Secondary aims were to compare length of hospital stay, general health improvement, and satisfaction between rUKA and mTKA.

Methods

A powered (1:3 ratio) cohort study was performed. A total of 30 patients undergoing rUKA were propensity score matched to 90 patients undergoing mTKA for isolated medial compartment arthritis. Patients were matched for age, sex, body mass index (BMI), and preoperative function. The Oxford Knee Score (OKS) and EuroQol five-dimension questionnaire (EQ-5D) were collected preoperatively and six months postoperatively. The Forgotten Joint Score (FJS) and patient satisfaction were collected six months postoperatively. Length of hospital stay was also recorded.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_16 | Pages 40 - 40
1 Oct 2016
Hamilton D Simpson P Patton J Howie C Burnett R
Full Access

Patient function is poorly characterised following revision TKA. Modern semi-constrained implants are suggested to offer high levels of function, however, data is lacking to justify this claim.

52 consecutive aseptic revision TKA procedures performed at a single centre were prospectively evaluated; all were revision of a primary implant to a Triathlon total stabiliser prosthesis. Patients were assessed pre-operatively and at 6, 26, 52 and 104 weeks post-op. Outcome assessments were the Oxford Knee Score (OKS), range of motion, pain rating scale and timed functional assessment battery. Analysis was by repeated measures ANOVA with post-hoc Tukey HSD 95% simultaneous confidence intervals as pairwise comparison. Secondary analysis compared the results of this revision cohort to previously reported primary TKA data, performed by the same surgeons, with identical outcome assessments at equivalent time points.

Mean age was 73.23 (SD 10.41) years, 57% were male. Mean time since index surgery was 9.03 (SD 5.6) years. 3 patients were lost to follow-up. All outcome parameters improved significantly over time (p <0.001). Post-hoc analysis demonstrated that all outcomes changed between pre-op, 6 week and 26 weeks post-op assessments.

No difference was seen between primary and revision cohorts in OKS (p = 0.2) or pain scores (p=0.19). Range of motion and functional performance was different between groups over the 2 year period (p=0.03), however this was due to differing pre-operative scores, post-hoc analysis showed no difference between groups at any post-operative time point.

Patients undergoing aseptic revision TKA with semi-constrained implants made substantial improvements in OKS, pain scores, knee flexion, and timed functional performance, with the outcomes achieved comparable to those of primary TKA. High levels of function can be achieved following revision knee arthroplasty, which may be important considering the changing need for, and demographics of, revision surgery.


The Journal of Bone & Joint Surgery British Volume
Vol. 92-B, Issue 3 | Pages 436 - 441
1 Mar 2010
Murnaghan ML Simpson P Robin JG Shore BJ Selber P Graham HK

We have tested the reliability of a recently reported classification system of hip morphology in adolescents with cerebral palsy in whom the triradiate cartilage was closed. The classification is a six-grade ordinal scale, based on the measurement of the migration percentage and an assessment of Shenton’s arch, deformity of the femoral head, acetabular deformity and pelvic obliquity.

Four paediatric orthopaedic surgeons and four physiotherapists received training in the use of the classification which they applied to the assessment of 42 hip radiographs, read on two separate occasions. The inter- and intra-observer reliability was assessed using the intraclass correlation coefficient and found to be excellent, with it ranging from 0.88 to 0.94. The classification in our study was shown to be valid (based on migration percentage), and reliable. As a result we believe that it can now be used in studies describing the natural history of hip displacement in cerebral palsy, in outcome studies and in communication between clinicians.


Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_I | Pages 113 - 113
1 Mar 2009
Dall G Simpson P McKenzie S Breusch S
Full Access

Background: Several factors can alter a cements viscosity and hence it’s handling characteristics. An in vitro study was performed to ascertain whether anecdotal observations of differences in handling between batches of the same cement brand existed.

Methods: 3 batches of Simplex P Tobramycin (SPT), Refobacin Bone Cement (RBC), SmartSet GHV (SSG) and Palacos R+G (PRG) were tested. 6 replicates of each batch were vacuum mixed and their viscosity in relation to time was measured in laboratory conditions (50 ±5% humidity and 23 ±1°C) using a rheometer. 6 replicates of each batch had their handling characteristics examined after they were hand mixed in theatre conditions.

Results: Inter and intra-batch variability was seen in the viscosity of all brands of cements tested. Inter-batch calculations were influenced by high intra-batch viscosity variability. The viscosity of RBC cement was very similar to SSG, but significantly different to PRG (p = 0.01 at 5N and p = 0.009 at 40 N).

Interpretation: Our results suggest that in clinical practice extrinsic factors such as preparation conditions and methods probably play a more important role than the cements intrinsic variability. However, variability in handling and viscosity will exist in all brands of cement prepared in theatre conditions and the surgeon needs to be aware why they may act differently.


Orthopaedic Proceedings
Vol. 90-B, Issue SUPP_II | Pages 309 - 310
1 Jul 2008
Simpson P Smit A Dall G Breusch S
Full Access

Introduction: An intra-medullary cement restrictor is an integral part of modern cementing technique in total hip arthroplasty. Failure of the restrictor to contain cement, flawed surgical technique or dislocation of the restrictor during pressurisation can all result in a deficient cement mantle. A radiographic analysis of hip replacements using a biodegradable restrictor was undertaken to determine the incidence of restrictor failure, the influence of femoral canal morphology on restrictor failure and to describe the cement mantle quality in successful and failed distal cement restriction.

Methods: x-rays from 299 consecutive hip replacements using the amberflex restrictor were analysed. The cortical index, canal-calcar ratio and femoral type, according to Dorr, were recorded. 3 modes of restrictor failure were identified:

Cement leakage –cement was seen to have escaped past the cement restrictor

Restrictor dislocation – the restrictor was 4 or more centimetres distal to the stem tip

Restrictor penetration –the tip of the femoral stem was resting on the restrictor All cement mantles were given a barrack grading.

Results: 84 cases of restrictor failure were observed – 44 dislocations, 24 leakages and 16 penetrations. The mode of failure was not correlated with femoral type, cortical index or canal-calcar ratio. A strong association was found between restrictor failure and grades c and d cement mantles using the chi squared test. A correlation between cortical index, canal-calcar ratio and femoral type was not observed.

Discussion: The ability of a cement restrictor to occlude the femoral canal and resist pressurisation is very important if a good quality cement mantle is to be achieved. Technical error was likely to be an important factor in many of the observed cases of restrictor failure, especially penetrative failure. Surgical technique is more important than femoral morphology in determining the successful use of this restrictor.


Orthopaedic Proceedings
Vol. 87-B, Issue SUPP_I | Pages 74 - 74
1 Mar 2005
Simpson P Reid R Porter D
Full Access

Aim: The aim of this study was to look at the presenting features, histological grade, size of primary tumour, method of treatment and patient and doctor delays in upper extremity Ewing sarcoma to observe the effects on local recurrence, metastasis and survival.

Methods: 19 patients with upper extremity Ewing sarcoma were identified using the Scottish Bone Tumour Registry which carries clinical, pathological and radiological data on the majority of bone tumours diagnosed in Scotland over the past 50 years.

Results: With increasing tumour Enneking grade at presentation there was a significantly higher mortality (X2=8.0606, p=0.0178). Patients with a higher grade also had an increased trend towards local recurrence (X2=5.1154, p=0.0775). Grade did not seem to influence the occurrence of metastasis. Patients with larger tumours tended to have a higher mortality (50% vs 27% dead at 5 years). All patients presented clinically with pain and all but two complained of some sort of swelling. It was found that there was a trend towards a higher grade in patients presenting with a longer duration of symptoms (X2=4.6269,p=0.0989). No difference in survival was noted between patients undergoing surgery and chemotherapy and patients undergoing radiotherapy and chemotherapy. Disease-free survival was 100% at both 5 and 10 years for Enneking Grade IIA, 56% at 5 and 10 years for Grade IIB and 0% at 5 years for Grade III.

Conclusions: This study re-emphasises the importance of a delay in diagnosis on outcome. Longer symptom duration results in a higher histological grade at presentation. In turn a higher presenting grade is associated with a higher mortality. In agreement with other studies a larger primary tumour correlates with a poorer outcome. Outcomes in terms of survival are comparable for groups treated with adjuvant radiotherapy or surgery.


The Journal of Bone & Joint Surgery British Volume
Vol. 86-B, Issue 8 | Pages 1105 - 1107
1 Nov 2004
Simpson P Oliver CW