Waiting times for arthroplasty surgery in Northern Ireland are among the longest in the National Health Service, which have been further lengthened by the onset of the SARS-CoV-19 global pandemic in March 2020. The Department of Health (DoH) in Northern Ireland has announced a new Elective Care Framework (ECF), with the framework proposing that by March 2026 no patient will wait more than 52 weeks for inpatient/day case treatment. We aimed to assess the feasibility of achieving this with reference to Total Hip Arthroplasty (THA).

Waiting list information was obtained via a Freedom of Information request to the DoH (May 2021) and National Joint Registry data was used to determine baseline operative numbers. Mathematical modelling was undertaken to calculate the time taken to meet the ECF target and also to determine the time to clear the waiting lists for THA using the number of patients currently on the waiting list and percentage operating capacity relative to pre-Covid-19 capacity to determine future projections.

As of May 2021, there were 3,757 patients awaiting primary THA in Northern Ireland. Prior to April 2020, there were a mean 2,346 patients/annum added to the waiting list for primary THA and there were a mean 1,624 primary THAs performed per annum.

The ECF targets for THA will only be achieved in 2026 if operating capacity is 200% of pre COVID-19 pandemic capacity and will be achieved in 2030 if capacity is 170%. Surgical capacity must exceed pre-Covid capacity by at least 30% to meet ongoing demand.

THA capacity was significantly reduced following resumption of elective orthopaedics post-COVID-19 (22% of pre-COVID-19 capacity – 355 THAs/annum post-COVID-19 versus 1,624/annum pre-COVID-19).

This modelling demonstrates that, in the absence of major funding and reorganisation of elective orthopaedic care, the targets set out in the ECF will not be achieved with regards to hip arthroplasty. Waiting times for THA surgery in the NHS in Northern Ireland are likely to remain greater than 52 weeks for most of this decade.

Introduction: A critical determinant of early dislocation following total hip arthroplasty (THA) is correct positioning of the acetabular component. This challenging aspect of THA has not been lessened by the introduction of more minimally invasive techniques. In this paper we introduce a simple and reproducible technique, which uses the transverse acetabular ligament (TAL) to determine cup orientation. We have used this technique as the sole method of cup orientation in our last 1000 consecutive primary total hips.

Methods: One thousand consecutive patients were studied in order to determine the prevalence of early dislocation (within 3 months) following acetabular component placement determined by reference to the transverse ace-tabular ligament. All patients underwent primary total hip arthroplasty via a posterolateral approach with a posterior repair.

Results: At a minimum follow-up of 9 months (range 9–39 months) 6 of the 1000 hips (0.6%) had dislocated.

Conclusion: Although multiple factors are known to contribute to this rate correct placement of the acetabular component is critical. As our results compare favourably with other published series where a posterior repair has been performed by extrapolation we feel that that the TAL does provide an acceptable method of determining cup orientation. The fact that it is independent of patient position on the table and is easy to locate with a minimally invasive approach makes it an attractive method.

Ensuring the accuracy of the intra-operative orientation of the acetabular component during a total hip replacement can be difficult. In this paper we introduce a reproducible technique using the transverse acetabular ligament to determine the anteversion of the acetabular component. We have found that this ligament can be identified in virtually every hip undergoing primary surgery. We describe an intra-operative grading system for the appearance of the ligament. This technique has been used in 1000 consecutive cases. During a minimum follow-up of eight months the dislocation rate was 0.6%. This confirms our hypothesis that the transverse acetabular ligament can be used to determine the position of the acetabular component. The method has been used in both conventional and minimally-invasive approaches.

Objective: To determine if a standard course of outpatient physiotherapy improves the range of knee motion following primary total knee arthroplasty.

Design: One hundred and fifty patients undergoing primary total knee arthroplasty were recruited and randomly assigned into two groups. Group 1 received a course of physiotherapy with a standard protocol over a six week period within 4 weeks of hospital discharge. Group 2 received no outpatient physiotherapy. All patients received inpatient physiotherapy for the length of their hospital stay. Range of knee motion was measured using a goniometer by members of the outcome team blinded to the randomisation. Validated knee scores (Oxford knee and Bartlet patellar) were collected. An SF12 health questionnaire was used as a generic outcome measure.

Results: Both groups were equally matched by age and sex. Although patients in Group 1 achieved greater range of knee motion than those in Group 2 this was not statistically significant. No difference was also noted in any of the outcome measures used.

Conclusion: We conclude that in patients undergoing primary total knee arthroplasty, inpatient physiotherapy with good instructions and a well-structured home exercise regime can dispense with the need for outpatient physiotherapy.

Purpose: The objective of this study was to observe the change in transfusion rate by decreasing the transfusion trigger for patients undergoing primary total knee arthroplasty.

There are no transfusion guidelines defined for Total knee arthroplasty (TKA), and each orthopaedic unit usually has its own protocol when it comes to transfusion. With the present climate of concern about non-autologous blood transfusions and transmission of infection, orthopaedic units are trying to keep their transfusion rates to a minimum and only transfuse when absolutely necessary.

Method: The transfusion trigger prior to protocol change was a haematocrit (Hct) < 0.31, which was then changed to a lesser trigger of Hct < 0.25. We collected data on 331 patients; 181 patients prior to the change and 150 patients after the change. Each patient had undergone a primary TKA by a single surgeon using the same operative technique.

Results: In the group prior to change in transfusion trigger (Hct < 0.31), 76% of patients were transfused 88% of females and 54% of males. In this pre-trigger change group, 100% of patients with a pre-operative Hb of 12g/dl or less were transfused.

Of the 150 patients reviewed after the change in transfusion trigger (Hct < 0.25), only 29% were transfused – 35% of females and 18% of males. 50% of patients with a pre-operative Hb of 12 g/dl or less were transfused.

Conclusion: A change in the transfusion trigger greatly reduced the transfusion rate (reduction of 45%) with no adverse patient events. Obviously, this has both clinical and financial benefits. Pre-operative Hb is the best indicator as to whether a patient will require a transfusion following TKA. In order to decrease transfusion rates further, patients with a pre-operative Hb < 12 g/dl may benefit from pre-operative boosting of their Hb.

Introduction Range of motion (ROM) is an important measure of outcome. A better understanding of the factors influencing ROM is important when counselling patients undergoing TKA.

Aim The aim of the study was to prospectively evaluate the influence of a number of selected variables on knee flexion at one year using the same prosthesis in a single surgeon series.

Patients and Methods 170 patients (57 males; 113 females) undergoing TKA were prospectively evaluated. The following data was recorded for each patient: age, gender, primary diagnosis, direction and magnitude of the preoperative axial deformity, BMI, cement use, preoperative and one year Oxford Knee Scores (OKS), the active and passive range of motion (ROM) preoperatively, at the end of surgery and at three month and one year review.

Results Average flexion values at each stage were as follows: preoperative (1110), end of surgery (1200), three months (1030) and one year (1070). There was a significant loss of flexion following TKA. The improvement between three months and one year however proved significant. Multiple regression analysis revealed that preoperative flexion was the strongest predictor of one-year flexion. Increasing age was also found to have a significant influence on final flexion. Gender, BMI, pre-operative OKS and cement use had no significant influence on final flexion. Patients tend to migrate towards a middle range of flexion i.e. those with poor flexion gain movement whilst those with good flexion tend to lose motion.

Conclusions Preoperative flexion is the strongest predictor of final flexion following TKA.

Introduction Fixed flexion deformity (FFD) represents a challenge during total knee arthroplasty (TKA). Furthermore, controversy exists as to the fate of FFD following TKA.

Aims The aims of this study were to determine how fixed flexion behaves in relation to surgery, factors that may influence or correlate with FFD both preoperatively and following TKA and the effect of FFD on outcome at one year.

Patients and Methods 133 patients (41 males; 92 females) undergoing TKA were prospectively studied. The following data was recorded for each patient: age, gender, primary diagnosis, direction and magnitude of the pre-operative axial deformity, BMI, preoperative and one year Oxford Knee Scores (OKS), the active and passive range of motion (ROM) preoperatively, at the end of surgery and at three month and one year review. FFD was defined as forced passive extension (FPE) greater than zero degrees.

Results Sixty-six patients (50%) had a preoperative FFD (mean, 60). At the end of surgery, this measured 10, 80 at 3 months and 40 at one year. When comparing those with a preoperative FFD to those with no FFD, there was no significant difference when assessing age, BMI or preoperative OKS. Preoperative FFD was significantly more common in males although there was no significant difference in the magnitude of FFD at any stage between males and females. There was a significant improvement in FFD at one year. Patients with a preoperative FFD were found to have significantly less flexion both preoperatively and at one year. When comparing those with FFD at one year to those with no FFD, those with FFD were significantly older and had significantly less flexion. There was no significant difference in BMI, OKS or gender.

Conclusions There is a definite trend when assessing the change in FFD with time. Correction at the time of surgery would appear to be important. Residual FFD is associated with reduced flexion at one year.

Introduction: The anatomy of the proximal femur is an important factor in the design of uncemented femoral prostheses for which the quality of fixation and the associated bony remodelling depend on the primary stability and optimal transmission of forces to the proximal femur. This study looks at the variation in the diameter of the proximal femur with age and sex in a homogeneous population.

Materials and Methods: We studied standardised pre-operative antero-posterior radiographs of the proximal femur of 2,777 patients who have undergone total hip arthroplasty using a custom implant over a 10 year period. The radiographs were corrected for magnification and a measurement made of the endosteal diameter at the narrowest point of the proximal femur. These measurements were used in the design and manufacture of the custom femoral implant.

Results: Of 2777 patients, 1588 were female and 1189 male. The mean age for females was 69.9 years (Range 30–92) and for males 67.2 years (Range 34–92). The mean proximal femoral canal diameter was 12.67mm for females and 13.36mm for males.

The mean diameter of the proximal femur increased from 12.99mm in males less than 60 years to 13.47mm in those of over 60. This increase was not statistically significant (p-value 0.064, 95% CI). In females there was a statistically significant increase in the mean diameter from 11.38mm in the under 60 age group to 12.90mm in those over 60 ( p-value 0.000, 95% CI).

Conclusions: The increase in the diameter of the proximal femur with age especially in females presents a significant challenge to the design and long-term survivability of uncemented femoral components. This is more so when viewed against the already good long term results available for cemented femoral implants.

Introduction: The use of minimal incision THR is increasing. The purpose of this study is to determine the effects of a change in operative technique from a standard incision to a minimally invasive incision at primary THR on peri-operative blood loss, analgesia requirement, length of stay, and complication rate. Two consecutive groups are compared.

Materials and methods: All patients who underwent a primary THR (posterior approach) by the senior author during a 3month period before and after a change in technique from a standard to a minimal incision were identified. 202 patients were analysed: 105 standard incisions and 97 minimal incisions. A retrospective chart review was used to collect age, height, weight, BMI, diagnosis and length of stay for each patient. Estimated peri-operative blood loss in units of blood was calculated by a validated formula. Morphine usage by PCA in the first 24hours post-operatively was recorded. Complications were identified.

Results: There was no significant difference in the mean age, height, weight or BMI between the 2 groups. Predominant diagnosis was primary osteoarthritis. Mean wound length for the standard incision was 16.6cms. Mean wound length for the minimal incision was 11cms. There was no difference in length of stay, mean 5.4days. There was no difference in morphine usage by PCA in the first 24hours, mean 39.4mgs.

Average estimated peri-operative blood loss for the standard incision group was 3.45 units and for the minimal incision group was 3.05 units (statistically significant, p-value 0.039, 95%CI). One patient after minimal incision had a superficial wound infection, which responded to oral antibiotics. There was one dislocation (standard incision).

Conclusions: Peri-operative estimated blood loss was less with a minimal incision but there was no difference in length of stay or analgesia requirement. A prospective RCT is now underway to determine the clinical efficacy of minimally invasive THR.

Objective: It is unknown whether routine physiotherapy is of benefit following total knee arthroplasty. Referrals are usually made by the inpatient physiotherapist or by the General Practitioners concerned about the patients range of knee motion. There have been no prospective, randomized, controlled studies in this area.

Design: One hundred and fifty patients undergoing primary total knee arthroplasty were recruited and randomly assigned into two groups. Ethical approval was given by the local ethics committee. Group 1 (n=55) received nine sessions of physiotherapy over a six-week period within 3 weeks of hospital discharge. Group 2 (n=76) received no outpatient physiotherapy. All patients received inpatient physiotherapy for the length of their hospital stay. Range of knee motion was measured using a goniometer by members of the outcome team blinded to the randomisation. Validated knee scores, Oxford knee, American knee society, and Bartlet patellar score were also collected. An SF-12 health questionnaire was used as a generic outcome measure.

Results: Both groups were equally matched in age, sex, diagnosis, and magnitude of deformity. Patients in Group 1 achieved an average loss in active range of motion of 2 degrees, whereas those in Group 2 achieved an average increase of 5 degrees. There is a significant difference in active range of motion between group 1 and group 2 (P=0.049). No difference in passive range of motion.

Conclusion: We concluded that the use of outpatient physiotherapy improves the range of knee motion to patients after total knee replacement at three months.

Introduction: Patellar management and related complications remain a major concern in total knee arthroplasty. Multiple problems can ensue in both resurfaced (fracture, loosening) and non-resurfaced patellae (pain).

Objective: We aim to evaluate the impact of secondary patellar resurfacing in patients with patellar related anterior knee pain having undergone a mobile bearing primary total knee arthroplasty without resurfacing.

Materials and methods: 2950 primary LCS mobile bearing total knee arthroplasties without patellar resurfacing were carried out between March 1992 and March 22003 by the senior author. Twelve patients underwent secondary patellar resurfacing for patellar related anterior knee pain. There were equal numbers male and female with a mean age of 72.1 years. There was a mean time of 27.9 months to secondary resurfacing procedure. We evaluated both clinical and radiological outcomes of this procedure.

Results: 0.4% patients required a secondary procedure. Only 3 had an unequivocal improvement in their symptoms. No morbidity was noted from the procedure.

Conclusions: The success rate of secondary patellar resurfacing is poor and we feel if this is to be offered to the patient for ongoing patellar related anterior knee pain that they be counseled carefully.

Introduction: Wear, and the resultant loosening and revision, of Total Hip Replacements (THRs) remains the limiting factor in the long term success of the prosthesis. Over 1 million Total Hip Replacements (THRs) are implanted each year, of which about 15% are revisions, most of which are a consequence of loosening of either femoral or acetabular components. This is frequently caused by either the mechanical (Wroblewski, 1986) or biological (Besong et al, 1997) response to the wear of ultra-high molecular weight polyethylene (UHMWPE) acetabular component.

In a previous study Bennett (2002, 2000) has demonstrated that the walking patterns of THR patients 5 years post operation directly correlated with the wear of the acetabular component, as measured radiographically. The present study considers THR patients 10 years post-operatively, ensuring more accurate wear measurements and more meaningful outcome measures.

Materials and Methods: Gait Analysis was performed on a number of THR patients following routine review using a Vicon 370 data capture system and a lower body marker set. This data was processed using Polygon software and joint angles were derived for the hip in the sagittal, coronal and transverse planes. A computer simulation was used to determine the path which each of 20 points on the prosthetic femoral head traces on the acetabulum during walking.

Results: It was found that patients exhibited different patterns of movement ranging from liner to multi-directional. Normal subjects have previously been found to exhibit multi-directional movement. Patients with mult-directional movement showed evidence of greater wear (Bennett et al., 2000).

Discussion and conclusion: Linear movement causes orientation hardening and wear resistance while multi-directional movement cause increased shear and greater wear rates. These differences in movement loci have a significant influence on UHMWPE wear rate and the long term survival of the implant.