Aims

To identify the responsiveness, minimal clinically important difference (MCID), minimal clinical important change (MIC), and patient-acceptable symptom state (PASS) thresholds in the 36-item Short Form Health Survey questionnaire (SF-36) (v2) for each of the eight dimensions and the total score following total knee arthroplasty (TKA).

Background

Total hip arthroplasty (THA) in patients with congenital dysplasia of the hip (CDH) is complex and challenging. The Crowe and Hartofilakidis classification systems are the most commonly used. However, neither encompasses the whole spectrum of disease and deformity and therefore does not guide modern surgical options.

We present a new classification system which aims to guide surgical strategy by focusing on the three main areas of disease and deformity: Cup defect; De-rotation of femoral neck ante-version; Height of femoral subluxation. Each component is graded from 1–3 based on the severity of deformity and the potential surgical strategy required (with 3 being the most severe). A total numerical score will reflect the overall degree of difficulty which may be used when assessing surgical outcomes.

The aim of this study is to assess the reliability of this new adult CDH classification system in the setting of THA.

Purpose

Although classic teaching holds that the least amount of constraint should be implanted, there is very little in the literature to substantiate this. This study attempts to quantify the influence of constraint and various indications upon functional outcome following aseptic first time revision knee arthroplasty. The null hypothesis was that the level of constraint and indication for surgery would not influence the functional outcome following revision knee replacement.

Introduction

We wished to quantify the influence of constraint and various principal indications upon functional outcome following aseptic first time revision knee arthroplasty.

We have attempted to quantify the influence of clinical, radiological and prosthetic design factors upon flexion following knee replacement. Our study examined the outcome following 101 knee replacements performed in two prospective randomized trials using similar cruciate retaining implants. Multivariate analyses, after adjusting for age, sex, diagnosis and the type of prosthesis revealed that the only significant correlates for range of movement at 12-months were the difference in posterior condylar offset ratio (p< 0.001), tibial slope (p< 0.001) and preoperative range of movement (p=0.025). We found a moderate correlation between 12-month range of movement and posterior tibial slope (R=0.58) and the difference of post femoral condylar offset (that is, post-operative minus preoperative posterior condylar offset, R=0.65). Posterior condylar offset had the greatest impact upon final range of movement highlighting this as an important consideration for the operating surgeon at pre-operative templating when choosing both the design and size of the femoral component.

Background: The determinants of range of movement following knee replacement may be surgically modifiable (tibial slope, posterior condylar offset or the level of the joint line) or non modifiable (pre-operative range of movement, sex or BMI). We aimed to quantify the influence of these factors upon restoration of flexion in the arthritic knee following knee replacement

Methods: Patients were included from two prospective trials for three different designs of knee replacement. Range of movement was recorded using a standard measuring technique preoperatively and 12 months after surgery. Radiological measurement was done by an independent observer and included the preoperative posterior condylar offset and the postoperative tibial slope, posterior condylar offset, posterior condylar offset ratio, varus-valgus alignment and Insall ratio. Multivariate analysis using stepwise selection was performed to determine the significant predictors of the range of movement at 12 months.

Results: The study includes 133 knee replacements performed on 125 patients. Complete clinical and radiographic data for preoperative and 12-month assessment was available for 101 knees and only these were included for the analyses. There was no significant difference between the three groups in terms of postoperative range of movement or the radiological parameters measured. Multivariate analysis after adjusting for age, sex, diagnosis and the type of prosthesis revealed that the only significant correlates of range of movement at 12-months were the difference in posterior condylar offset ratio, tibial slope and preoperative range of movement. Moderate correlation was noted between range of movement at 12 months and posterior tibial slope (R=0.58) and the difference of post femoral condylar offset (that is, post-operative minus preoperative posterior condylar offset, R=0.65). Preoperative range of movement had only a weak correlation with post-operative range of movement (R=0.20).

Conclusions: We found that the posterior femoral condylar offset had the greatest impact upon final range of movement. We would encourage the operating surgeon at pre-operative templating to take this into account when choosing size and design of femoral component.

Introduction Infection is a disastrous complication of arthroplasty surgery, requiring multidisciplinary treatment and debilitating revision surgery. As between 80–90% of bacterial wound contaminants originate from colony forming units (CFU’s) present in operating room air tending to originate from bacteria shed by personnel present within the operating environment, any steps that can reduce this bacterial shedding should reduce the chances of wound contamination. These steps have included the use of unidirectional downward laminar airflow theatre systems, and the introduction of theatre attire modelled on this principle (e.g. total body exhaust suits). Our unit has introduced the use of the Stryker T4 Personal Protection System helmet in conjunction with laminar flow theatre systems. This study compares an enclosed helmet system used with standard gowns, with standard hood & mask attire.

Method 12 simulated hip arthroplasty operations were performed, six using disposable sterile impermeable gown, hood and mask, with a further 6 using the T4 helmet & hood. Each 20 minute operation consisted of a series of arm and head movements simulating movements performed during surgery. Air was sampled at wound level on a sterile draped operating table using a Casella slit sampler, sampling at 700l/minute. Samples were incubated on Blood agar for 48 hours at 37oc & the CFU’s grown were counted.

Results The mean number of CFU’s for the helmet was 9.33 with hood and mask attire yielding 49.16 CFU’s (S.Ds 6.34 & 26.17; p value 0.0126). In all cases, the organism isolated was a coagulase negative staphylococcus

Conclusion Although the sample size was small, we demonstrated a fivefold increase in the number of CFU’s shed when using hood and mask attire compared to personal helmet and sterile hood. We conclude that the helmet system is superior to non-sterile hood & mask at reducing bacterial shedding by theatre personnel.

Aim: To determine the quality of life and radiological outcome of the rotating hinge total knee prosthesis as a salvage procedure for failed knee arthroplasty.

Methods: Forty-seven consecutive revision total knee arthroplasties, using the rotating hinge component, implanted between November 1983 and June 1997, were studied. The principal indications for surgery were pain with ligamentous laxity and gross bone loss. There were 43 patients, 11 males, 32 females, 19 left and 28 right, 21 with rheumatoid disease and 22 with osteoarthritis. The mean age at revision was 68 years, mean time from primary procedure to revision of 8 years and a mean number of previous knee procedures of 1.6 (range 1–5). The average time to final follow-up was 5 years. Quality of life was determined using the Nottingham Health Profile (NHP) combined with standard clinical and radiological assessment.

Results: Of the 47 revision procedures, full clinical follow-up information was available on 43 (91.5%), radiographic follow-up on 38 (80.9%). Complications occurred in 10 out of the 47 arthroplasties (21.3%) including 4 deep infections, 2 femoral fractures, 2 patients with clinically apparent aseptic loosening and 2 significant extensor mechanism problems. Survivorship analysis revealed a 5year cumulative implant survival of 89%. Significant improvements in quality of life (pain and physical mobility) were shown at 12 months post-operatively.

Discussion: This is a prospectively-studied series of salvage arthroplasty procedures. We regard quality of life as a key indicator of surgical success after knee arthroplasty. Rotating hinge arthroplasty offers objective and reproducible improvement in quality of life for failed knee arthroplasty with ligamentous instability.