Although the importance of sound statistical principles in the design and analysis of data has gained prominence in recent years, biostatistics, the application of statistics to the analysis of biological and medical data, is still a subject which is poorly understood and often mishandled. This review introduces, in the context of orthopaedic research, the terminology and the principles involved in simple data analysis, and outlines areas of medical statistics that have gained prominence in recent years. It also lists and provides an insight into some of the more common
The management of bone loss in revision replacement of the knee remains a challenge despite an array of options available to the surgeon. Bone loss may occur as a result of the original disease, the design of the prosthesis, the mechanism of failure or technical
Many radiographic techniques have been described for measuring patellar height. They can be divided into two groups: those that relate the position of the patella to the femur (direct) and those that relate it to the tibia (indirect). This article looks at the methods that have been described, the logic behind their conception and the critical analyses that have been performed to test them.
Since 1996 more than one million metal-on-metal
articulations have been implanted worldwide. Adverse reactions to
metal debris are escalating. Here we present an algorithmic approach
to patient management. The general approach to all arthroplasty
patients returning for follow-up begins with a detailed history,
querying for pain, discomfort or compromise of function. Symptomatic
patients should be evaluated for intra-articular and extra-articular
causes of pain. In large head MoM arthroplasty, aseptic loosening
may be the source of pain and is frequently difficult to diagnose.
Sepsis should be ruled out as a source of pain. Plain radiographs
are evaluated to rule out loosening and osteolysis, and assess component
position. Laboratory evaluation commences with erythrocyte sedimentation
rate and C-reactive protein, which may be elevated. Serum metal
ions should be assessed by an approved facility. Aspiration, with
manual cell count and culture/sensitivity should be performed, with
cloudy to creamy fluid with predominance of monocytes often indicative
of failure. Imaging should include ultrasound or metal artifact
reduction sequence MRI, specifically evaluating for fluid collections
and/or masses about the hip. If adverse reaction to metal debris
is suspected then revision to metal or ceramic-on-polyethylene is indicated
and can be successful. Delay may be associated with extensive soft-tissue
damage and hence poor clinical outcome.
The fracture most commonly treated by orthopaedic surgeons is that of the distal radius. However, as yet there is no consensus on what constitutes an ‘acceptable’ radiological position before or after treatment. This should be defined as the position that will predict good function in the majority of cases. In this paper we review the radiological indices that can be measured in fractures of the distal radius and try to identify potential predictors of functional outcome. In patients likely to have high functional demands, we recommend that the articular reconstruction be achieved with less than 2 mm of gap or step-off, the radius be restored to within 2 mm of its normal length, and that carpal alignment be restored. The ultimate aim of treatment is a pain-free, mobile wrist joint without functional limitation.
The advent of computer-assisted knee replacement surgery has focused interest on the alignment of the components. However, there is confusion at times between the alignment of the limb as a whole and that of the components. The interaction between them is discussed in this article. Alignment is expressed relative to some reference axis or plane and measurements will vary depending on what is selected as the reference. The validity of different reference axes is discussed. Varying prosthetic alignment has direct implications for surrounding soft-tissue tension. In this context the interaction between alignment and soft-tissue balance is explored and the current knowledge of the relationship between alignment and outcome is summarised.
The management of patients with a painful total knee replacement requires careful assessment and a stepwise approach in order to diagnose the underlying pathology accurately. The management should include a multidisciplinary approach to the patient’s pain as well as addressing the underlying aetiology. Pain should be treated with appropriate analgesia, according to the analgesic ladder of the World Health Organisation. Special measures should be taken to identify and to treat any neuropathic pain. There are a number of intrinsic and extrinsic causes of a painful knee replacement which should be identified and treated early. Patients with unexplained pain and without any recognised pathology should be treated conservatively since they may improve over a period of time and rarely do so after a revision operation.
Most proximal humeral fractures are stable injuries of the ageing population, and can be successfully treated non-operatively. The management of the smaller number of more complex displaced fractures is more controversial and new fixation techniques have greatly increased the range of fractures that may benefit from surgery. This article explores current concepts in the classification and clinical aspects of these injuries, reviewing the indications, innovations and outcomes for the most common methods of treatment.
The survivorship of contemporary resurfacing arthroplasty of the hip using metal-on-metal bearings is better than that of first generation designs, but short-term failures still occur. The most common reasons for failure are fracture of the femoral neck, loosening of the component, osteonecrosis of the femoral head, reaction to metal debris and malpositioning of the component. In 2008 the Australian National Joint Registry reported an inverse relationship between the size of the head component and the risk of revision in resurfacing hip arthroplasty. Hips with a femoral component size of ≤ 44 mm have a fivefold increased risk of revision than those with femoral components of ≥ 55 mm irrespective of gender. We have reviewed the literature to explore this observation and to identify possible reasons including the design of the implant, loading of the femoral neck, the orientation of the component, the production of wear debris and the effects of metal ions, penetration of cement and vascularity of the femoral head. Our conclusion is that although multifactorial, the most important contributors to failure in resurfacing arthroplasty of the hip are likely to be the design and geometry of the component and the orientation of the acetabular component.
With the development of systems of trauma care the management of pelvic disruption has evolved and has become increasingly refined. The goal is to achieve an anatomical reduction and stable fixation of the fracture. This requires adequate visualisation for reduction of the fracture and the placement of fixation. Despite the advances in surgical approach and technique, the functional outcomes do not always produce the desired result. New methods of percutaneous treatment in conjunction with innovative computer-based imaging have evolved in an attempt to overcome the existing difficulties. This paper presents an overview of the technical aspects of percutaneous surgery of the pelvis and acetabulum.
Evaluation of patients with painful total knee replacement requires a thorough clinical examination and relevant investigations in order to reach a diagnosis. Awareness of the common and uncommon problems leading to painful total knee replacement is useful in the diagnostic approach. This review article aims to act as a guide to the evaluation of patients with painful total knee replacement.
The menisci of the knee have an important role in load-bearing and shock absorption within the joint. They may also function as secondary stabilisers, have a proprioceptive role, and aid the lubrication and nutrition of the articular cartilage. Complete or partial loss of a meniscus can have damaging effects on a knee, leading to serious long-term sequelae. This paper reviews the consequences of meniscectomy and summarises the body of evidence in the literature regarding those factors most relevant to long-term outcome.
