Aim

Advocates of Debridement-Antibiotics-and-Implant-Retention (DAIR) in hip peri-prosthetic joint infection (PJI) argue that a procedure not disturbing a sound prosthesis-bone interface is likely to lead to better survival and functional outcome compared to revision. However, no evidence supports this. This case-control study's aims were to compare outcome of DAIRs for infected 1° total hip arthroplasty (THA) with outcomes following 1° THA and 2-stage revisions of infected 1° THAs.

Introduction

Knee arthroplasty is an effective intervention for painful arthritis when conservative measures have failed. Despite recent advances in component design and implantation techniques, a significant proportion of patients experience problems relating to the patella-femoral joint (PFJ).

Detailed knowledge of the shape and orientation of the normal and replaced femoral trochlea groove is critical when considering potential causes of anterior knee pain. Furthermore, to date it has proved difficult to establish a diagnosis due to shortcomings in current imaging techniques for obtaining satisfactory coronal plane motion data of the patella in the replaced knee.

The aim of this study was to correlate the trochlea shape of normal and replaced knees with corresponding coronal plane PFJ kinematic data.

For medial compartment disease UKR has many advantages over TKR. They give better function, faster recovery, lower morbidity and mortality but have a higher revision rate. Matched studies from the England and Wales National Joint Registry showed they are 60% more likely to achieve excellent outcomes (OKS>41) and 30% more likely to have excellent satisfaction. UKR patients were discharged 1.4 days earlier, had 35% less readmissions and 50% less major complications such as DVT/PE, infection, CVA and MI. The death rate was significantly lower: The hazard ratios being 0.2x at 30 days, 0.5x at 90 days and 0.85x at 8 years. However at 8 years the revision rate was 2x higher and the reoperation rate was 1.4x. If 100 patients receiving TKR had UKR instead, the result would be around one fewer death and three more reoperations in the first 4 years. If patients were aware of this most would select a UKR.

The main reason why UKR have a high revision rate in registries is that most surgeons do small numbers and restrict their use to patients with very early disease, who often do badly. In the NJR 8% of knees are UKR and surgeons do on average 5 per year. Surgeons doing more than 20% of knees as UKR have a much lower re-operation rate which is similar to that of TKR. The Mobile bearing UKR can safely be used in up to 50% allowing many patients to have the advantages of UKR and a low re-operation rate.

Implant registries are set up to register implants. They therefore collect information about both primary and revision joint replacements. If a revision is linked to a primary it is then possible to determine the revision rate of the primary. This information is, however, of limited value as detailed information that affects the revision rate such as indications for the primary and the revision, and surgical technique used are not recorded. As a result comparisons of different implant designs and implant types are not reliable. For example implants that are commonly used in young or active patients are likely to have higher revision rates than those used in elderly sedate patients even though they may be better. Similarly, implants that are easy to revise will have higher revision rates than those more difficult to revise even if they provide better functional results. Finally, implants that are commonly used by more experienced surgeons will tend to have lower revision rates than those used by less experienced surgeons. Data from registries are therefore useful for identifying hypotheses that can formally be tested in other ways.

Cemented unicompartmental knee replacement (UKR) has been used for many years and has excellent results in many follow-up studies. However, concerns about the quality of fixation, cementing errors, and radiolucent lines have encouraged the development of cementless prostheses. Mobile bearing UKR are probably the ideal implants for cementless fixation as the loads at the interface tend to be compressive. Prior to the widespread introduction of cementless mobile bearing UKR three studies have been performed to assess this device. In a randomised radiostereometric (RSA) study the migration of cementless and cemented devices were the same in the second year suggesting the quality of fixation achieved was similar. A clinical randomised study demonstrated a dramatic reduction in radiolucent lines with cementless components compared to cemented and no difference in clinical outcome. A prospective cohort study of 1000 patients demonstrated no overall difference in complications or revision rate and identified no contraindications for cementless fixation. There are however anecdotal reports of occasional tibial plateau fracture and early subsidence of cementless components. Data from the National Registers would suggest that the revision rate with cementless is about half that compared to cemented however this difference may be because only experienced surgeons are using the cementless device.

Cementless mobile bearing UKR does seem to be a good evolutionary step in the development of UKR. It is important however that surgeons are trained in the use of the device and are careful with the technique.

Previous attempts to measure coronal plane patellofemoral kinematics following knee replacement have suffered from methodological drawbacks; the patella being obscured by the components, metal artefact and technical inaccuracies. The aim of this study was to assess whether there was any significant difference in the patellofemoral kinematics between normal, TKR and PFJR patients using the validated MAUS™ technique (combining motion analysis with ultrasound).

60 patients were recruited into three groups; normal healthy volunteers (Normal), TKR, and PFJR patients. The MAUS technique incorporates a 12 camera analysis system (providing gross alignment data for tibial and femoral segments) and an ultrasound probe (providing coordinates of bony landmarks on patella femur and tibia) during a squat exercise. 6 DOF kinematics were described between 0 and 90° flexion. The validated accuracy of the MAUS technique registering the ultrasound images within the motion capture system is 1.84 mm (2 × SD).

Movements of the Normal group were significantly different from the TKR group (p=0.03) and the PFJR group (p<0.01), whilst there was no significant difference between the TKR and PFJR groups (p=0.27).

Our data suggest that many aspects of patellofemoral kinematics are absent following TKR and PFJR, which could be addressed in future designs of knee TKR and PFJR.

Unicompartmental Knee Replacement (UKR) is associated with fewer complications, faster recovery and better function than Total Knee Replacement (TKR). However, joint registers demonstrate a higher revision rate, which limit their use. Common reasons for revision include aseptic loosening and pain. Currently most UKRs are cemented; Cementless UKR was introduced to address these problems. In a randomised trial cementless fixation was found to have similar outcome scores but fewer radiolucencies than cemented fixation. It was also quicker and simpler. In a large multicentre cohort study in the hands of experienced surgeons it was found that following cementless UKR the incidence of complications was similar to cemented and there were no additional contra-indications. There were also no complete radiolucencies, which are common after cemented fixation. These studies demonstrate that cementless UKR are safe and effective and achieve better fixation with fewer radiolucencies than cemented UKR. They therefor suggest that cemented fixation should decrease the incidence of revision for aseptic loosening and for pain associated with radiolucency, and as a result the revision rate of UKR in the joint registers should decrease. Preliminary data from the registries demonstrates that this is happening.

Cement is the commonest method used to fix femoral components in the UK. This is not surprising as in the UK cemented fixation has provided better results than cementless fixation. The results of cemented fixation do however depend on the design of the stem. Polished collarless tapered stems are now the most widely used stems in the UK. These stems subside within the cement mantle thus compressing the cement and cement-bone interface and preventing these from failing. They are thus very tolerant of poor quality cementing. As a result aseptic loosening is extraordinarily rare even in young active patients. Compared with cementless fixation cement is very forgiving. It can be used with ease whatever the anatomy of the proximal femur and whatever the bone quality. Correct leg length can also easily be achieved. Thigh pain does not occur and intra-operative fractures are very rare. The antibiotics in the cement decrease the incidence of infection. In addition cement provides an effective barrier to particulate debris and joint fluid under pressure. The only real disadvantage of cemented fixation is that it may take longer than cementless fixation. However this extra time spent is compensated by the cheaper implant costs.

It has been proposed that a major advantage of surface replacement is that it is easy to revise and that the outcome of such revisions is good. This seems logical as the femoral head can easily be removed, the acetabular component can be cut out and a primary hip replacement can be inserted. Indeed a number of studies have shown good outcome following revision, particularly for femoral neck fracture. When we initially reviewed the results of our revisions we found that the operations were straight forward and the results were good provided the reasons for revision were neck fractures, loosening, infection and causes other than soft tissue reactions. When the reason for revision was soft tissue reaction, otherwise known as pseudotumour, the outcome was unsatisfactory with poor hip scores, and high rates of complications, revisions and recurrences. These were generally a manifestation of the soft tissue damage caused by the pseudotumours. We therefor recommended that early revisions should be considered with soft tissue reaction. By undertaking revisions earlier we have found that the results have improved but there are still cases with poor outcomes.

Objectives

This study examines variations in knee arthroplasty patient reported outcome measures according to patient age.

Unicompartmental Knee Replacement (UKR) is associated with fewer complications, faster recovery and better function than Total Knee Replacement (TKR). However, joint registries demonstrate a higher revision rate in UKR, limiting its use. Currently most UKRs are cemented and performed using a minimally invasive technique. In joint registries, common reasons for revision include aseptic loosening and pain. These problems could potentially be addressed by using cementless implants, which may provide more reliable fixation.

The objectives of this study were to compare the quality of fixation (determined by the incidence and appearance of radiolucencies), and clinical outcomes of cemented and cementless UKR at five years.

A randomised controlled trial was established with 63 knees (62 patients) randomised to either cemented (32 patients) or cementless UKR (30 patients). Fixation was assessed with fluoroscopic radiographs aligned to the bone-implant interface at one and five years. Outcome scores were collected pre-operatively and at one, two and five years, including Oxford Knee Score (OKS), American Knee Society Score, objective and functional (AKSS-O/F) and Tegner Activity Scale (TAS), expressed as absolute scores and 0–5 year change (δ) scores.

Four patients died during the study period. There were no revisions. Mean operative time was 11 minutes shorter in the cementless group (p=0.029). At five years, there was no significant difference in any outcome measure except AKSS-F and δAKSS-F which were significantly better in the cementless group (both p=0.003). There were no femoral radiolucencies in either group. There were significantly more tibial radiolucencies in the cemented group (20/30 vs 2/27, p< 0.001). There were nine complete radiolucencies in the cemented group and none in the cementless group (p< 0.001).

Cementless fixation provides improved fixation at five years compared to cemented fixation in UKR, maintaining equivalent or superior clinical outcomes with a shorter operative time and no increase in complications.

Introduction

Hip arthroscopy is a relatively new procedure and evidence to support its use remains limited. Well-designed prospective clinical trials with long-term outcomes are required, but study design requires an understanding of current practice. Our aim was to determine temporal trends in the uptake of non-arthroplasty hip surgery in England between 2001 and 2011.

Introduction

Patella tendonitis is common amongst sportsmen. No published evidence of this injury in elite professional footballers exists. The aim of this study was to determine the frequency of this injury in the elite professional footballer, along with the impact of such an injury on the amount of time missed and the outcomes of various treatment options.

Indications for Unicompartmental Knee Arthroplasty (UKA) vary between units. Some authors have suggested, and many surgeons believe, that medial UKA should only be performed in patients who localise their pain to the medial joint line. This is despite research showing a poor correlation between patient-reported location of pain and radiological or operative findings in osteoarthritis. The aim of this study is to determine the effect of patient-reported pre-operative pain location and functional outcome of UKA at one and five years.

Pre-operative pain location data were collected for 406 knees (380 patients) undergoing Oxford medial UKA. Oxford Knee Score, American Knee Society Scores and Tegner activity scale were recorded preoperatively and at follow-up. 272/406 (67%) had pure medial pain, 25/406 (6%) had pure anterior knee pain and 109/406 (27%) had mixed or generalised pain. None had pure lateral pain. The primary outcome interval is one year; 132/406 patients had attained five years by the time of analysis and their five year data is presented.

At one and five years, each group had improved significantly by each measure (mean δOKS 15.6 (SD 8.9) at year one, 16.3 (9.3) at year five). There was no difference between the groups, nor between patients with and without anterior knee pain or isolated medial pain.

We have found no correlation between preoperative pain location and outcome. We conclude that localised medial pain should not be a prerequisite to UKA and that it may be performed in patients with generalised or anterior knee pain.

Introduction

Solid or cystic pseudotumour is a potentially destructive complication of metal on metal (MoM) couples, usually needing revision surgery. However, complete clearance of the pseudotumour is unlikely at times. This prospective case-controlled study reports cases which had recurrence after revision surgery for pseudotumour related to metal on metal hip couples.

Introduction

Classification systems are used throughout Trauma and Orthopaedic (T&O) surgery, designed to be used for communication, planning treatment options, predicting outcomes and research purposes. As a result the majority of T&O knowledge is based upon such systems with most of the published literature using classifications. Therefore we wanted to investigate the basis for the classification culture in our specialty by reviewing Orthopaedic classifications and the literature to assess whether the classifications had been independently validated.

Introduction

Knee injuries are common amongst footballers. The aim of this study was to establish frequency and variation of knee injuries within one English Premier League (EPL) professional football club over two seasons, to assess number of days missed due to injury, and analyse current treatment regimen for each injury type.

Introduction

Stem geometry is known to influence the outcome in THA; however it is unknown whether the material properties, stiffness in particular can influence the stem stability and outcome. The aim of this study was to measure the influence of stem material properties on micromotion and migration using Roentgen Stereophotogrammetric Analysis (RSA) system.

Introduction

Foot and ankle injuries are a common occurrence amongst all footballers. The aim of this study was to establish the frequency and variation of foot and ankle injuries within one English Premier League (EPL) professional football club over the course of a season and attempt to identify any factors associated with the injuries.

We examined data from a large prospectively collected dataset which followed up patients after Exeter total hip replacement (THR) - the Exeter Primary Outcome Study. We studied 78 patients who had total hip replacement for osteoarthritis on a morphologically normal hip, and in whom the other hip was also morphologically normal for comparison. All selected patients had complete patient outcome data at 1 and 5 years, and x-rays at 1 year were available.

We measured accuracy of reconstruction on AP Pelvis radiographs. The parameters measured were difference in height of lesser trochanter from horizontal pelvic line (LLD); length from ASIS to greater trochanter (indicating abductor length, AL); length from symphysis to centre of femoral head (SFH); length from centre of head to axis of femur (offset). We examined clinical outcomes including gain of Oxford Hip Score (DOHS) at 1 and 5 years, absolute OHS at 1 and 5 years, and absolute SF-36 Physical Functioning and Role Physical scores at 1 and 5 years.

Examining the ratios of AL, SFH, Offset, Offset to SFH ratio and LLD between side of THR and unaffected side all showed marked variation. Thus the ratio of SFH varied from 0.85 to 1.11. For further analysis we divided the patients into 3 groups on the basis of variability of the ratio from 1; we examined whether the clinical scores above varied between these 3 groups. 1 way ANOVA demonstrated no significant difference for any of the clinical outcomes for any of the 5 grouped x-ray variables.

Accuracy of reconstruction has been shown to affect the risk of dislocation after THR. Our results indicate that clinical outcomes of total hip replacement appear resilient to some degree of surgical inaccuracy. Future trials of navigation should be designed to demonstrate not only improved accuracy but also improved clinical outcome.