Objective

Wearable sensors have enabled objective functional data collection from patients before total knee replacement (TKR) and at clinical follow-ups post-surgery whereas traditional evaluation has solely relied on self-reported subjective measures. The timed-up-and-go (TUG) test has been used to evaluate function but is commonly measured using only total completion time, which does not assess joint function or test completion strategy. The current work employs machine learning techniques to distinguish patient groups based on derived functional metrics from the TUG test and expose clinically important functional parameters that are predictive of patient recovery.

Introduction

A total knee arthroplasty (TKA) is the standard of care treatment for end-stage osteoarthritis (OA) of the knee. Over the last decade, we have observed a change in TKA patient population to include younger patients. This cohort tends to be more active and thus places more stress on the implanted prothesis. Bone cement has historically been used to establish fixation between the implant and host bone, resulting in two interfaces where loosening may occur. Uncemented fixation methods provide a promising alternative to cemented fixation. While vulnerable during the early post-operative period, cementless implants may be better suited to long-term stability in younger patient cohorts. It is currently unknown whether the surgical technique used to implant the cementless prostheses impacts the longevity of the implant. Two different surgical techniques are commonly used by surgeons and may result in different load distribution across the joint, which will affect bone ingrowth. The overall objective of the study is to assess implant migration and in vivo kinematics following cementless TKA.

A common step to revision surgery for infected total knee replacement (TKR) is a thorough debridement. Whilst surgical and mechanical debridement are established as the gold standard, we investigate a novel adjuvant chemical debridement using an Acetic Acid (AA) soak that seeks to create a hostile environment for organisms, further degradation of biofilm and death of the bacteria.

We report the first orthopaedic in vivo series using AA soak as an intra-operative chemical debridement agent for treating infected TKR's. We also investigate the in vitro efficacy of AA against bacteria isolated from infected TKR's.

A prospective single surgeon consecutive series of patients with infected TKR were treated according to a standard debridement protocol. Patients in the series received sequential debridement of surgical, mechanical and finally chemical debridement with a 10 minute 3% AA soak.

In parallel, we isolated, cultured and identified bacteria from infected TKR's and assessed the in vitro efficacy of AA. Susceptibility testing was performed with AA solutions of different concentrations as well as with a control of a gentamicin sulphate disc. The effect of AA on the pH of tryptone soya was also monitored in an attempt to understand its potential mechanism of action.

Physiological responses during the AA soak were unremarkable. Intraoperatively, there were no tachycardic or arrythmic responses, any increase in respiratory rate or changes in blood pressure. This was also the case when the tourniquet was released. In addition, during the post-operative period no increase in analgesic requirements or wound complications was noted. Wound and soft tissue healing was excellent and there have not been any early recurrent infections at mean of 18 months follow up.

In vitro, zones of inhibition were formed on less than 40% of the organisms, demonstrating that AA was not directly bactericidal against the majority of the clinical isolates. However, when cultured in a bacterial suspension, AA completely inhibited the growth of the isolates at concentrations as low as 0.19%v/v.

This study has shown that the use of 3% AA soak, as part of a debridement protocol, is safe. Whilst the exact mechanism of action of acetic acid is yet to be determined, we have demonstrated that concentrations as low as 0.19%v/v in solution in vitro is sufficient to completely inhibit bacterial growth from infected TKR's.

TER is a viable surgical option in patients with advanced RA with painful stiff elbows. We retrospectively analysed 22 TER performed in 21 patients over a 12 year period by a single surgeon, with a mean follow up of 64 months (10–145). Disability of the arm, shoulder and hand (DASH) scores were performed pre-operatively and post-operatively in patients through postal questionnaires. The mean age was 59.1 years (32–78). There were 12 women and 9 men. The mean pre-operative DASH score was 72.3 (45.0–91.7) and post-operatively improved to 46.8 (21.7–94.2). Complications included infection, peri-operative fracture, peri-prosthetic fracture and aseptic loosening. There were 6 revisions performed, 2 for peri-prosthetic fracture, 2 for infection, 1 for intra-operative fracture and 1 for symptomatic aseptic loosening. Four patients had died due to unrelated causes. The 10 year survival rate with symptomatic aseptic loosening as the end point was 93% and revisions for all reasons was 69%. Follow up radiographs (in those without revision) were reviewed and 10 had satisfactory positioning of the prosthesis, 5 had loosening of the humeral or radial component and 1 had inadequate cement mantle but was clinically asymptomatic. TER is a rewarding procedure in with advanced RA. Our results are comparable to other published studies.

We retrospectively analysed a single surgeon series of 22 TER in 21 patients over a 12 year period. The mean age and follow up was 59.1 years and 64 months respectively. DASH scores assessed pre and post op confirmed a significant improvement. Complications included infection, intra-operative fracture, peri-prosthetic fracture and aseptic loosening. 6 revisions were performed for various reasons.4 patients had died due to unrelated causes. The 10 year survival rate with symptomatic aseptic loosening as the end point was 93%. 5 patients had radiological loosening but were clinically asymptomatic. TER is a rewarding procedure in with advanced RA.

The aim of this study was to compare the outcome of cemented TKR using either oxidized zirconium (oxinium) or cobalt chrome (CoCr) femoral components in patients undergoing simultaneous bilateral TKR. Patients involved in the study received one of each prosthesis, thereby acting as their own control. The hypothesis was that there would be no difference in the clinical and radiographic outcome between the two prosthetic materials.

Forty consecutive patients who were undergoing bilateral Genesis ll TKR consented to participate in the study. Patients were assessed preoperatively, at five days, six weeks and one, two and five years, postoperatively. The outcome measures included the KOOS, Knee Society Score, BOA Patient Satisfaction Scale, and radiographs at six weeks and one, two and five years. In two patients polyethlylene exchange was performed at 56 months from surgery during patellofemoral resurfacing. The four retrieved polyethylene liners were studied for wear with the aid of a stereo zoom microscope and an environmental scanning electron microscope (ESEM). Both the patients and the all examiners were blinded as to the prosthesis type throughout the study.

Forty patients (80 knees) were included in the study. At five years, three patients were deceased and two had developed senile dementia. No patients were lost to follow up. At five years from surgery the CoCr knee was preferred by 41% of patients compared to 13% who preferred the Oxinium knee (p=0.009). There was no significant difference in range of motion between the two prosthesis at five days, six weeks or one, two and five years. There were also no significant differences between the two prostheses in any of the other variables assessed. The four retrieved polyethylene inserts showed similar patterns of wear in terms of both wear types and patterns under examination with both the stereo zoom and scanning electron microscope with no clear differences between CoCr and Oxinium bearing against the polyethlylene. There was no difference in the grade or incidence of radiographic lucencies between the two prosthesis at five years.

At five years after surgery the only significant difference between the Genesis II Oxinium prosthesis and the CoCr prosthesis was a subjective preference for the CoCr prosthesis by a higher proportion of patients. There were no unexpected complications associated with the use the Oxinium femoral implants. In the four retrieved polyethylene liners, no significant differences were identified between the two prosthesis materials in terms of detectable wear type and patterns. Continued follow up of this cohort is planned to establish whether Oxinium femoral implants have an improved survivorship compared to CoCr femoral component in total knee replacement to warrant the additional cost.

The results of PLLA screws for ACL reconstruction have demonstrated no significant clinical differences when compared to metallic screws up to two years. However, studies examining PLLA-HA screws are lacking, as are medium term outcomes of bioresorbable screws. This study aims to compare the clinical outcome of ACL reconstruction with a PLLA-HA to a titanium screw, and to assess the extent of resorption of the PLLA-HA screw at two and five years after ACL reconstruction.

Forty patients were randomised to receive either a PLLA-HA or titanium RCI interference screw for ACL reconstruction. Both examiners and patients were blinded to screw type. Patients were prospectively reviewed at 24 and 60 months after surgery with full IKDC assessment, Instrumented Ligament Testing, Lysholm knee score. MRI scans were performed at two and five years following surgery.

Five years after surgery, one patient with a titanium screw had an ACL graft rupture and had undergone revision surgery. Of the remaining 39 patients, 38 (97%) were reviewed at five years. There was no significant difference between the two groups in the volume of the tibial (p=0.89) or femoral (p=0.22) tunnels at five years. Significant screw resorbtion at five years was seen in 77% on the tibial side and 88% on the femoral side in the PLLA group. Good ossification was evident on five year MRI in 94% of the tibial screws and 56% of the femoral screws. In the PLLA-HA group peri tunnel bone marrow oedema was present in 35% of patients on the tibial side and 53% of patients on the femoral side at five years. There was no peri-tunnel bone marrow oedema evident in the titanium group. Peri-graft ganglion cyst was evident on MRI scan on the tibial side in 24% of patients from the PLLA-HA group and 18% of the titanium group (p=0.67). There was no significant difference between the PLLA-HA group and the titanium group on any of the other clinical parameters including IKDC subjective knee score (mean 93), symptoms, range of motion, instrumented ligament laxity (mean 1.8 mm) or overall IKDC grade (90% normal or nearly normal).

ACL reconstruction with PLLA-HA bioabsorbable screws affords comparable clinical and subjective results to titanium screws at five years after surgery. Significant progression of PLLA HA screw resorption occurs between two and five years, with over 75% of screws demonstrating some resorption by five years. However, complete resorption was only evident in a small number of patients. ACL reconstruction with a PLLA HA screw has excellent clinical outcomes and progressive screw resorption and ossification is evident at five years.

This study evaluated the long term outcome of isolated posterior cruciate ligament (PCL) reconstruction. Thirty patients underwent surgery with hamstring tendon autograft after failing conservative management. At 10 years after surgery patients were assessed with radiographs, full IKDC examination and KT1000 instrumented testing. The mean IKDC subjective knee score was 87 out of a possible 100. Regular participation in moderate to strenuous activities improved from 26% preoperatively to 88% of patients. At 10 years endoscopic reconstruction of the PCL with hamstring tendon autograft is effective in reducing knee symptoms. Patients can expect to continue participating in moderate to strenuous activties over the long term. Osteoarthritis is observed in some patients with 18% showing some loss of joint space which compares favorably with non-operatively managed PCL injuries. This is a successful procedure for symptomatic patients with PCL laxity who have failed conservative management.

This study explores the outcomes of a pilot project involving five Orthopaedic services in developing approaches to improve the consistency and equity of clinical decision-making for access to treatment.

The pilot was conducted in two phases; the first involved development of retrospective and prospective data collection and analysis tools including use of:

The Orthopaedic Integrated CPAC tool:

Large variations in internal equity were found within most services. Additionally a significant, systemic equity issue is apparent between patients prioritised for major joints versus other conditions. The pilot has made useful progress in developing improvement tools and processes targeting electives service management, improvements in prioritisation and clinical decision making, and funding and planning decisions. The pilot has also raised issues for further CPAC development and national service policy.

Total hip arthroplasty surgery may be associated with substantial loss of blood often necessitating blood transfusion.

The risks associated with blood transfusions are widely known. Haemostatic drugs have been tried in the past to try and reduce this, and there has been renewed interest in these recently, in particular Aprotinin (Bayer).

Aprotinin is a serine protease inhibitor, which has been shown to reduce blood loss in cardiac surgery by up to eighty percent.

The aim of our study was to investigate whether or not high dose Aprotinin can reduce blood loss and transfusion rates in patients’ undergoing total hip arthroplasty.

This was a randomised double blind controlled clinical trial, where 50 patients were randomised to receive either Aprotinin (2 x 106 KIU followed by an infusion of 5 x 105 KIU/hr), or an equivalent volume of normal saline.

Blood loss and transfusion rates were measured as well as the incidence of deep vein thrombosis.

There was a significant reduction in total blood loss seen in the Aprotinin group, median 817±350, when compared to the control group, median 1191±386. This translates to a 31% reduction in blood loss.

DVT and transfusion rates were not significantly different between the two groups.

There was no complications or deaths seen in the Aprotinin group.

The use of high dose Aprotinin results in a reduction in blood loss in total hip arthroplasty. It has been proved to reduce blood loss in cardiac surgery, and although papers have shown it can reduce blood loss in orthopaedic surgery, its’ use should not as yet be routine.

Further work is required to investigate the possibility of a future role for Aprotinin in orthopaedic surgery, as well as its’ mode of action. Until then more established methods of blood conservation should be used.