Abstract

Abstract

Abstract

Abstract

Corail implants have shown to give good results in elective total hip replacements (THR) and in hemi-arthroplasties. Pre-operative planning to identify the correct size of the Corail implant is vital for good post-operative outcomes. An undersized implant can lead to subsidence. The aim of the study was to review the incidence of subsidence. Post-operative radiographs of trauma patients (n=39) and elective (n=45) patients who had Corail femoral implants were reviewed. The implant-to-canal (I:C) ratio were calculated at the given 50% and 70% levels of the Corail implant. Follow up radiographs were reviewed to identify subsidence. The average age of patients was 80.3 years (range 66–93 years) in hemi-arthroplasties and 61 years (range 18–88) in elective THRs. The implant to canal (I:C) ratio at the 50% and 70% levels in trauma patients were 0.77 (range 0.54 – 0.97) and 0.81 (range 0.59 – 0.94) respectively. In elective patients, the ratios at the 50% and 70% marks were 0.77 (range 0.57 – 0.98) and 0.81 (0.56 – 0.95). One case of subsidence was seen in a collarless implant and I:C ratios at 50% and 70% were 0.57 and 0.56. A larger study is required to determine the reliability of this novel ‘implant:canal’ ratio to predict incidence.

Introduction

CT based systems that are used to create custom components and custom cutting guides in total knee arthroplasty (TKA) have variable methods for accounting for the thickness of remaining cartilage that may influence component sizing and bone resection. Little information has been published about the thickness of this cartilage, especially on the posterior femoral condyles. Failure to account for this cartilage may lead to under-sizing of the femoral component, or a reduction in the posterior condylar offset that may adversely affect flexion after TKA.

Introduction

While prosthesis survival in Total Knee Arthroplasty (TKA) exceeds 90% at 10 year, failures do occur. One area of concern has been the potential for metal allergy or metal sensitivity causing persistent pain, swelling or early failure of the implant in some patients. Definitive tests for diagnosing metal allergy and metal sensitivity have not been developed and this field remains controversial. In most cases where metal sensitivity is a concern, metals such as Chromium and Nickel are implicated. Despite the lack of good diagnostic tests for identifying these patients, several orthopedic prosthesis manufacturers have developed implants made of Titanium or ceramic designed for use in patients where concerns exist regarding metal allergy. In the absence of good diagnostic tests, use of these devices in patients that self identify is one option. To date, little information has been presented about the incidence of self reported metal sensitivity in patients undergoing joint replacement. This study was undertaken to determine the incidence of self reported metal allergy or sensitivity in patients undergoing total knee arthroplasty.

Introduction

Patellar resurfacing during Total Knee Arthroplasty (TKA) is controversial. Problems unique to patellar resurfacing may be influenced by available patellar component design. These issues include; over-stuffing (the creation of a composite patellar-prosthesis thickness greater than the native patella) that may contribute to reduced range of motion; and over-resection of the native patellar bone that may contribute to post-operative fracture. Prosthesis design may play a role in contributing to these problems. Component diameter and thickness are quite variable from one manufacturer to another and little information has been previously published about optimal component dimensions. This anatomic study was performed to define the native patellar anatomy of patients undergoing TKA, in order to guide future component design.

Aim: To investigate the magnitude of revenue lost by the Department of Trauma and Orthopaedics at Ports-mouth Hospitals NHS Trust in 2007 as a result of providing outpatient viscosupplementation joint injections.

Methods: Data was collated on all outpatient intra-articular hyaluronic acid viscosupplementation performed by our department in 2007. Information on existing HRG tariffs for orthopaedic outpatient attendances as well as clinical coding of joint injections by our department was also gathered.

Results: The 2007/2008 tariffs for orthopaedic outpatient first and follow-up appointments were £147 and £73 respectively for adults, and £157 and £85 respectively for children (under 17 years of age). No additional mandatory tariff currently exists for joint injections performed in the outpatient setting. During our study period, the cost of a dose of viscosuplementation (Hyaluronic acid 60mg/ 3 ml) varied between £213 and £248. A total of 812 doses of viscosupplementation were administered to outpatients by our department resulting in pharmaceutical costs of £175,126. Only 751 cases of outpatient appointment with joint injection (all types) were recorded and coded by the department.

Conclusions:

As long as no mandatory DoH tariff exists for out-patient joint injections, outpatient viscosupplementation remains an expensive service for trusts to provide and may warrant rationalisation.

We have used a modified technique of cervical osteotomy to treat a consecutive series of 23 patients with chronic slip of the upper femoral epiphysis. It has been successful in correcting both moderate and severe deformities with a low incidence of avascular necrosis, comparable to that seen after subtrochanteric osteotomies. We describe the operative details and discuss the features which make cervical osteotomy technically superior to intertrochanteric and subtrochanteric procedures.

Bone samples from the iliac crest of patients with no signs of bone disorder were treated with collagenase to remove the collagen component and so allow detailed observation of the mineral hydroxyapatite. Both polished and unpolished surfaces were studied in the scanning electron microscope and they showed that the mineral component of bone is composed of small rounded units about 10 nm across which are fused together to form larger spheroidal units roughly 100 nm in diameter. In the unpolished surfaces these 100 nm units are seen to aggregate to form columns approximately parallel to their neighbours and with numerous interconnections forming a continuous mineral phase. The polished sections also show the hydroxyapatite as a continuous phase of contiguous spheroids and the holes from which the collagen fibres were removed are clearly revealed. Lamellations in the surface are interpreted as resulting from adjacent layers of collagen fibres having orientations approximately perpendicular to each other.

Total hip replacement was performed in 27 hips of patients who had sickle cell anaemia with avascular necrosis of the femoral head. The disease was bilateral in 11 patients. Considerable medical problems were encountered although most of the patients had exchange transfusion before surgery (86%), which prevented postoperative sickle cell crises in all but two cases. At the primary operation hard sclerotic bone was seen in nine femora with complete obliteration of the femoral canal. There were four femoral fractures, three following perforation of the shaft due to this hard bone. There was a very high morbidity due to loosening in both cemented and uncemented prostheses. With a rate of 59% over a cumulative 5.5 year period, revision was being performed at an average of only 43 months. Surgeons should be aware of these problems.

1. Attention is drawn to that type of rigid congenital flat foot in which the talus lies vertically instead of horizontally.

2. This deformity is rare, but if not treated successfully leads to an ugly, painful foot in adolescence.

3. The experience of five patients forms the basis of the present preliminary account. One adolescent and two young children under the age of five were treated unsuccessfully by both conservative and operative measures. More recently in two children with bilateral deformity open operation has been successful in restoring the shape of the foot.

4. The operation is essentially a reduction of a subluxation at the talo-navicular and subtalar joints. It entails freeing the head of the talus sufficiently to allow it to be lifted dorsally and laterally. The talus is then anchored in position by transplanting the distal end of the peroneus brevis tendon through the neck of the bone.

It has been fascinating to trace the gradual erection of the British edifice of orthopaedics, and nostalgic to recapture a memory, however fleeting, of some of the figures who built it and taught us so much of our sum of knowledge half-way through the twentieth century—the remarkable spell of Robert Jones, the lofty, ascetic Tubby, the pugnacious Openshaw, the forceful and enthusiastic Hey Groves, the earnest but irascible Laming Evans, the equable and thoughtful Elmslie, the restless and exuberant Trethowan. It is always tempting to conclude: "those were the days." It is probably wise to do no more than record the events and leave judgment of progress to a later century. But we are being judged already and not always kindly or even truthfully. We are justified surely in priding ourselves on what has already been achieved, and on the service that orthopaedic surgery now gives to the community and promises for the future. In concern for this aspect of our work we have perhaps tended to neglect our capacity for basic research. But we are aware of this shortcoming, as witness our closer relationships with research departments of universities and royal colleges, and our increasing contacts with colleagues in the basic sciences. Finally, apart from the most intellectual snob and the pessimistic cynic, all must surely rejoice at the enthusiasm, industry and ability of our young colleagues—the orthopaedic surgeons of to-morrow.