Aim

Prosthetic joint infection (PJI) is a major complication in THA. Nasal carriage with S. Aureus is a well-defined risk factor for infection in hospitalized patients. Risk for infection is reduced up to 50% by eradication therapy. Since PJI rates are very low and only 25% of the population are carriers, significant differences are hard to show and reports on PJI have been inconclusive. We analysed the effect of S. Aureus eradication therapy in THA.

Introduction

Studies show that cup malpositioning using conventional techniques occurs in 50 to 74% of cases defined. Assessment of the utility of improved methods of placing acetabular components depends upon the accuracy of the method of measuring component positioning postoperatively. The current study reports on our preliminary experience assessing the accuracy of EOS images and application specific software to assess cup orientation as compared to CT.

The resection of distal femur and proximal tibia during TKR is 90° to mechanical axis but in a normal knee, the joint line is 3°varus. We measured various angles on long-leg alignment radiographs. The mean age was 58.7 years. The mean HKA axis was 4.3°± 0.5°, mPTA was 3.8°±0.5°, mLDFA was 3.6±0.5° and aLDFA was 8.6°±0.5°. The mean HKA & MPTA were approximately 4°varus, mLDFA 4° valgus & aLDFA 8°valgus. The alignment of the knee to its mechanical axis during TKR is therefore not anatomic. This raises a question whether the knee should be aligned to its kinematic axis instead of mechanical axis.

Computer-assisted navigation during total knee replacement has been advocated to improve component alignment and hence reduce failure rates and improve quality of life. The technique involves the placement of trackers via pins placed in both the femur and tibia throughout the surgery. It has been proposed that complication rates are higher in knee arthroplasty when computer navigation is used, compared to when it is not, due to increased risks from the pin tracker sites. Potential risks from pin sites include infection, fractures of the tibia or femur and pin site pain. In this study we present the post-operative complication rates related to pin tracker sites of computer navigated knee arthroplasty from a single surgeon at one centre.

A database was compiled including all patients undergoing knee arthroplasty with computer navigation between January 2009 and December 2013 performed by a single surgeon at one centre. A retrospective study was undertaken having identified a total of 321 patients (642 pin sites) with 287 having undergone total knee replacement, 29 Uni-condylar knee replacement and five having undergone patellofemoral knee replacement. There 131 males and 190 females with a mean age of 69.4 [range 48–89]. There were no exclusions. The patient's notes were reviewed for any complications that occurred as a result of pin sites including infection, pin site pain and fracture.

Only one patient (0.03%) was identified with a superficial pin site infection that was successfully managed with oral antibiotics only. There were no fractures or other complications identified in any of the other patients.

In this series, the complication rates resulting from pin tracker sites was very low suggesting computer navigation does not increase the risks of knee arthroplasty. There were no cases of femoral or tibial fractures in this series, as have previously been reported. It is therefore likely that the technique of pin site placement is important in limiting the risk of complications. In this series a standard technique was used in all cases. Stab incisions are always used rather than a percutaneous technique and the wounds closed with clips and protected with dressings at the end of the surgery. Uni-cortical drilling is sufficient to provide stability of the trackers intra-operatively and minimises the risk of thermal necrosis therefore bi-cortical placement is avoided. Self-drilling pins are used on power and inserted perpendicular to the bone on high torque and low speed. The tourniquet is not inflated until after the pins have been inserted. It is thought that using this technique offers a safe method of pin tracker placement ensuring low complication rates.

Chondral damage within the knee commonly occurs during sport following direct trauma or following degeneration through overuse. Radio frequency energy chondroplasty (RFC) can be used as an alternative to mechanical chondroplasty in the arthroscopic treatment of chondral lesions. Current literature supports the theoretical advantage of RFC and purports to in vitro improvements in cartilage structure and function following RFC. We conducted a retrospective study of patients undergoing RFC for isolated chondral lesions in the knee and assessed the short term clinical benefits.

Retrospective analysis was completed of operative notes and arthroscopic images of all patients who underwent arthroscopic chondroplasty at the royal Devon and Exeter Hospital between January 2009 and June 2012. Inclusion criteria included 1 to 2 defined chondral lesions, less than 2cm2, of Outerbridge grade II-IV, treated via arthroscopic RFC. Exclusion criteria included diffuse articular cartilage damage, additional pathologies affecting the knee or subsequent further injuries or invasive procedures to the knee. Data was collected via a subjective and objective questionnaire assessing patient outcome.

35 patients met the inclusion criteria, 32 were successfully followed up. Male: female ratio was 16:16, with a mean age of 39.5 (range 19–60).

84% (n=27) of patients experienced a significant reduction in pain (mean reduction of 51%, p < 0.001) lasting until the time of study (median of 21 months, range 9 to 31 months). There was no correlation between change in symptoms and site and grade of chondral lesion. Pre-operative instability symptoms did not significantly improve following RFC. Satisfaction with treatment was in direct correlation with pain relief achieved.

Our study appears to support current literature by suggesting short term improvements to pain following the use of RFC on chondral lesions. Greater population size and longer follow-up are required to provide more significant conclusions.

Introduction

The goal of revision total hip arthroplasty (THA) for acetabular defects is to achieve the best stability and fixation with available host bone. Tritanium is a highly porous metal construct with a titanium matrix coating. We are reporting our experience of utilizing this material in patients with major acetabular defects.

Oxford hip and knee scores are being used by many heath care commissioners to determine whether individual patients are eligible for joint replacement surgery. Oxford scores were not designed for use in deciding whether patients are suitable for surgery and they are not validated as a triage tool. The aim of this study was to assess what effect these predetermined threshold Oxford Scores would have on a contemporary patient cohort.

An analysis was undertaken of 4254 pre-operative Oxford scores in patients who had already undergone either hip resurfacing, a total hip, total knee or unicompartmental knee replacement surgery at our institution between 2008 and 2011. We assessed how these scores would affect the decision making pathway determining which patients would be eligible for joint replacement surgery. We also evaluated the effects this would have on patients undergoing surgery in terms of gender, sex, age and type of arthroplasty.

22.4% hip resurfacings, 10.0% of total hip replacements, 7.5% total knee replacements and 11.0% unicompartmental knee replacements would have been declined on the Oxford Scores system. The selection criteria as set by the health care commissioners was found to be ageist as there was a bias against older patients obtaining surgery. There was a bias against different forms of arthroplasty, particularly those patients suitable for resurfacing or unicompartmental knee replacement. It was also sexist as it selectively excluded male patients from surgery.

Rather than using pre-operative Oxford scores to discern which patients are eligible for surgery, evaluation of patient factors which are reported to adversely affect the outcome of hip and knee replacement surgery, may offer a better solution to improving quality of care. Oxford scores are undertaken to benchmark a providers performance and not to decide on an individual's suitability for surgery.

Osteotomy through the bare area of olecranon minimises the damage to articular cartilage in the trans-olecranon approach to the distal humerus. In this study we have identified a reliable and easily reproducible anatomical land mark to make sure that the osteotomy passes through the bare area.

Two methods were used to determine the line for the osteotomy, in the first a line from the lateral epicondyle perpendicular to the olecranon and in the second an intra-articular marker was used to determine the osteotomy. In 5 cadavers the osteotomy with lateral epicondylar line as a marker went 2 mm proximal to the bare area. Of the 5 cadavers dissected with a marker passed to the angle of olecranon the osteotomy went through the bare area of olecranon in three specimens and just proximal in the other two.

In conclusion a cheveron osteotomy with the base of the chevron on the lateral epicondylar line will be the ideal site to make sure that the osteotomy passes through the bare area of the olecranon.

Fractures of the shaft of the humerus are often treated conservatively in a hanging cast or a humeral brace. The conservative management of this fracture is often prolonged and quite uncomfortable for the patient. Some of the patients will need an operative fixation after a trial of conservative management.

We retrospectively looked at 72 consecutive patients with fractures of the shaft of the humerus that presented in our institution over a period of two years. The fracture pattern, treatment modality time to union and the number that needed operative fixation following a trial of conservative treatment was analysed. Of the 72 patients 4 were lost to follow-up. 45 patients had a 1.2.B or 1.2.C type of fracture and 23 had a 1.2.A type of fracture. 29 (41%) were successfully treated conservatively, 11 (16%) patients were operated as the primary procedure and 15 (22%) patients were operated due to delayed or non union. 13 (19%) patients were operated within 4 weeks of the fracture as their alignment was not acceptable on their weekly follow-up.

The average time to union in the patients treated conservatively was 22 weeks, while that of the patients treated primarily by open reduction and plating was 14 weeks (p-value<0.05). Patients who needed operation after initial conservative management required prolonged period of rehabilitation and union time was 32.2 weeks. At the time of fracture union 72% of the patients who had been treated conservatively had joint stiffness requiring physiotherapy, while only 18% of those who had an open reduction and internal fixation had stiffness and required physiotherapy. (p-value < 0.05).

In conclusion careful consideration should be given before it is decided to treat this fracture conservatively especially in the case of 1.2.A fracture pattern.