Incorrect registration during computer assisted total knee arthroplasty (CA-TKA) leads to malposition of implants. Our aim was to evaluate the tolerable error in anatomic landmark registration. We incorrectly registered the femoral epicondyles, femoral and tibial centers, as well as the malleoli and documented the change in angulation or rotation. We found that the distal femoral epicondyles were the most difficult anatomic landmarks to register. The other bony landmarks were more forgiving. Identification of the distal femoral epicondyles has a high inter- and intra-observer variability. Our observation that there is less than 2 mm of safe zone in the anterior or posterior direction during registration of the medial and lateral epicondyles may explain the inability of CA-TKA to improve upon the outcomes of conventional TKA.

Restoration of the joint line of the knee during primary and revision total knee arthroplasty is one of many critical steps that directly influence patient outcomes. Fifty MRI scans of normal atraumatic knees were analyzed to determine a quantitative relationship between the joint line of the knee and the bony landmarks of the knee joint: femoral epicondyles, metaphyseal flare of the femur, tibial tubercle, and proximal tibio-femoral joint. We describe the relationship of these six anatomic landmarks about the knee in a gender and size independent manner. This description supports a simple three-step algorithm allowing orthopaedic surgeons to calculate, instead of estimate, the location of the joint line of the knee.

Introduction: Pain and mass lesions around hip resurfacing are reported with increasing frequency. The aetiology is unknown but reaction to metal wear debris and mechanical impingement have both been suggested. We are aware of a group of our patients with significant pain following resurfacing. We sought to correlate metal ion levels with X-ray findings and any local soft tissue reaction around the prosthesis.

Methods: Patients with significant groin pain following hip resurfacing were identified from routine clinics. Blood was tested for cobalt and chromium levels using inductively coupled mass spectrometry in all patients. Cup abduction angle and femoral stem version were estimated from plain radiographs. Patients underwent ultrasound scan (USS) of the affected hip joint. Bilateral prostheses were excluded to avoid confounding.

Results: 47 unilateral painful hip resurfacings (24 female) were identified. USS was performed in 42 patients and was abnormal in 25 (15 female). Abnormalities ranged from simple joint effusion with or without synovial thickening, through to cystic masses in the posterior joint and solid masses related to the ileopsoas tendon similar to the appearances previously described in pseudotumours.

A two sample t-test demonstrated cobalt and chromium ion levels were significantly higher in patients with abnormalities on USS (p=0.038, p=0.05 respectively), patients with normal USS were more likely to have a retroverted femoral component (p=0.01).

Discussion: We describe two groups of patients with a painful hip resurfacing: those with raised metal ions and local soft tissue reaction, and those with lower metal ions and no soft tissue reaction. The retroverted stems in the second group could cause an iatrogenic cam-type impingement. Metal ion levels are useful to guide further imaging. Raised levels should prompt investigation for a soft tissue abnormality with either USS or MRI, lower levels suggest investigation should look for mechanical impingement with imaging such as CT.

Antero-posterior (AP) pelvis and lateral x-rays are routinely prescribed for the positional diagnosis of proximal femoral fractures, however; the usefulness of the lateral x-ray has not been previously presented in the literature. In addition, the clinical advantage of internally rotated AP views has also not been tested. This study aims to define the value of the lateral x-ray, and the internally rotated AP view, in the assessment and treatment planning of proximal femoral fractures.

X-rays from 359 consecutive patients with proximal femoral fractures were divided into: ‘un-positioned’ AP (greater trochanter overlying the lateral femoral neck), clear neck AP (internally rotated to show the lateral femoral neck), and lateral views. Three blinded reviewers independently assessed the x-rays in sequence and noted the positional diagnosis and displacement. This was then compared with the intra-operative diagnosis used as gold standard.

The addition of a lateral x-ray to an AP view significantly increased the rate of the correct diagnosis made by the reviewers when compared to an AP view alone, in intracapsular fractures only (p < 0.013), but not for extracapsular fractures (p = 0.27).

The use of clear neck AP views did not increase the rate of correctly diagnosing the type of fracture when compared to unpositioned AP views. This applies for both intracapsular (p = 0.57), and extracapsular fractures (p < 0.823).

Although orthopaedic rote dictates that every fracture should be visualised in two views, this study has shown with that for the majority of hip fractures one view is adequate and safe. The lateral x-ray is only required for intracapsular fractures that appear undisplaced on the AP view and should not be performed routinely. Specially positioned AP views are not required and should be avoided due to the unnecessary pain caused and the needless cost.

In the UK, surveillance for surgical site infection is mandatory for orthopaedic surgery. NHS trusts must participate for at least one surveillance period (3 months) every year in at least one of four categories:- hip replacement, knee replacement, hip hemiarthroplasty or open reduction of long bone fractures. Surgical site infections (SSIs) are defined as infections related to a surgical procedure that affects the surgical wound or deeper tissues handled during the procedure. Since mandatory surveillance began in 2004, rates of SSIs have markedly decreased. This is postulated to be secondary to increased early detection. Shorter postoperative stays and underestimation are also likely to be influential factors. We reviewed 150 consecutive lower limb arthroplasties performed at a district general hospital from July to September 2007. All inpatient data were collected as part of the Health Protection Agencies mandatory surveillance. We reviewed this data and notes for recorded evidence of infections or complications for minimum of one year after surgery. We reviewed computer records for recorded microbiological evidence of infection preoperatively and postoperatively. The operations performed during the surveillance period were:- 60 primary total knee replacements (TKRs), 37 primary hip replacements (THRs), 25 hip resurfacings, 15 unicondylar knee replacements, 3 patello-femoral joint replacements, 6 revision TKRs and 4 revision THRs. No SSI’s were detected during the mandatory surveillance period (i.e the inpatient stay, mean 5.61 days, Range 2–44 days). Two SSI’s (1.33%) were detected in our follow up period. Both were superficial wound infections. The first, a 53 year old hip resurfacing patient who was discharged 3 days postoperatively and developed Staphyloccocal infection 5 days later. The other was a 76 year old who underwent THR surgery, was discharged at day 6 and presented on day 12 with Pseudomonas wound infection. Both cases were initially diagnosed and treated successfully with oral antibiotic by GPs. One 61 year old patient who underwent hip resurfacing presented at day 62 with pain. X-rays showed loosening. Deep infection was suspected but hip aspirate, and inflammatory markers were negative. He is being monitored in the outpatient department. Our analysis also revealed that 3 patients had urinary tract infections (Coliforms on MSU) on the day of surgery and none have had postoperative complications. Intraoperative soft tissue samples for one patient who underwent one stage revision TKR grew Haemolytic Streptoccocus but there has been no evidence of postoperative complications. Other complications seen were THR dislocations (n=3) for reasons other than infection, 2 were revised. Persistent pain (n=2), common peroneal nerve palsy (n=1). We conclude that detection of SSI during inpatient stay is almost impossible. Mandatory surveillance seems excessive and a waste of resources

Introduction Patients sustaining fractures of the proximal femur, with co-morbid medical problems, have increased rates of morbidity and mortality. Chronic renal failure is one such co-morbidity. This study examines the outcome in patients with chronic renal failure who sustain fractures of the proximal femur.

Patients and Methods All patients with a fractured neck of femur who presented to our department from September 1997 to March 2004 were retrospectively reviewed. Eighteen of these patients were found to have chronic renal failure requiring dialysis. Medical records were reviewed and information was collected and analysed. A full literature review was conducted.

Results There were nine intra-capsular fractures and nine extra-capsular fractures. Four patients with intra-capsular fractures were treated by internal fixation and four by arthroplasty. One patient with an intra-capsular fracture was treated non-operatively. Eight patients with extra-capsular fractures were treated with a dynamic hip screw device and one was treated using a cephalo-medullary nail. There were sixteen deaths at a mean of seven months post-operatively (range 0 to 24). Factors that may influence outcome and the relevant literature are discussed.

Conclusions Patients with chronic renal failure who sustain fractures of the proximal femur appear to have a poor outcome regardless of type of fracture or its subsequent management.