A review of intellectual property rights in biotechnology.

Intellectual property rights protect innovations and their authors. This review describes the concepts of copyright and patent with their relative merits and drawbacks. An understanding of intellectual property rights is important for doctors to allow protection of their work but should not be at the expense of scientific progress.

The SMILES prosthesis in salvage revision knee surgery.

Revision total knee arthroplasty using a second generation modular rotating hinge design was done on thirty two knees in 30 patients over an 8-year period. Twenty-nine knees in 29 patients were followed up for 4.5-11 years (mean, 58 months). Four prostheses failed and two patients had died and one patient was lost to followup. Indications for revision were recurrent sepsis (five knees), component failure (four knees), ligamentous instability (two knees), aseptic loosening (10 knees), fracture (six knees), and gross bone loss (five knees). Early results have demonstrated improvement in both the Knee Society knee and function Scores and range of movement. The Knee Society knee score improved from 26 preoperatively to 68 postoperatively. The function score improved from 27 preoperatively to 75 postoperatively. One patient had evidence of aseptic loosening on radiographs, and the patellofemoral complication rate was low at 6%. This short-term clinical and radiographic review has demonstrated encouraging results in the use of a custom-made second generation rotating hinge component when used in revision knee surgery.

Do Biologic Agents Increase the Risk of Infection in Patients Undergoing Lower Limb Arthroplasty Surgery?

BACKGROUND: Biologic agents have contributed significantly to the management of patients with in rheumatoid arthritis (RA). A significant proportion of patients with RA still require arthroplasty procedures however. It is unclear whether these agents increase the risk of post operative infection after lower limb arthroplasty. METHOD: A literature search was performed for articles published over the last 10 years in the English language examining the association between anti-tumour necrosis factor inhibitors and the incidence of post operative infection in patients with RA undergoing hip and knee arthroplasty procedures. RESULTS: One large meta-analysis has been published suggesting a 2-fold increase in infection rates following orthopaedic surgery in patients receiving biological agents. When subgroup analysis of arthroplasty cases alone was performed the finding failed to reach significance. However, several further studies have demonstrated both an increased risk for surgical site infection with the use of biological agents and several conflicting articles argue the opposite. CONCLUSION: There is no current consensus on this topic. The safety of continuation of perioperative anti-TNF-α therapy in patients undergoing lower limb arthroplasty procedures is unclear. There is also little robust guidance from specialist rheumatologic societies. There is need for large scale multicentre randomised controlled trials to address this issue.

Narrowing of the neck in resurfacing arthroplasty of the hip: a radiological study.

Narrowing of the femoral neck after resurfacing arthroplasty of the hip has been described previously in both cemented and uncemented hip resurfacing. The natural history of narrowing of the femoral neck is unknown. We retrospectively measured the diameter of the femoral neck in a series of 163 Birmingham hip resurfacings in 163 patients up to a maximum of six years after operation to determine the extent and progression of narrowing. There were 105 men and 58 women with a mean age of 52 years (18 to 82). At a mean follow-up of five years, the mean Harris hip score was 94.8 (47 to 100) and the mean flexion of the hip 112.5 degrees (80 degrees to 160 degrees ). There was some narrowing of the femoral neck in 77% (125) of the patients reviewed, and in 27.6% (45) the narrowing exceeded 10% of the diameter of the neck. A multiple logistic regression analysis showed a significant association (chi-squared test (derived from logistic regression) p = 0.01) of narrowing with female gender and a valgus femoral neck/shaft angle. There was no significant association between the range of movement, position or size of the component or radiological lucent lines and narrowing of the neck (chi-squared test; p = 0.10 (flexion), p = 0.08 (size of femoral component), p = 0.09 (size of acetabular component), p = 0.71 (femoral component angulation), p = 0.99 (lucent lines)). There was no significant difference between the diameter of the neck at a mean of three years (2.5 to 3.5) and that at five years (4.5 to 5.5), indicating that any change in the diameter of the neck had stabilised by three years (sign rank test, p = 0.60). We conclude that narrowing of the femoral neck which is found with the Birmingham hip resurfacing arthroplasty is in most cases associated with no adverse clinical or radiological outcome up to a maximum of six years after the initial operation.

The results of primary Birmingham hip resurfacings at a mean of five years. An independent prospective review of the first 230 hips.

We report an independent prospective review of the first 230 Birmingham hip resurfacings in 212 patients at a mean follow-up of five years (4 to 6). Two patients, one with a loose acetabular component and the other with suspected avascular necrosis of the femoral head, underwent revision. There were two deaths from unrelated causes and one patient was lost to follow-up. The survivorship with the worst-case scenario was 97.8% (95% confidence interval 95.8 to 99.5). The mean Harris hip score improved significantly (paired t-test, p < 0.05) from 62.54 (8 to 92) pre-operatively to 97.7 (61 to 100) at a mean of three years (2.1 to 4.3), then deteriorated slightly to a mean of 95.2 (47 to 100) at a mean of five years. The mean flexion improved from 91.5 degrees (25 degrees to 140 degrees) to 110.4 degrees (80 degrees to 145 degrees) at a mean of three years with no further improvement at five years (111.2 degrees; 70 degrees to 160 degrees). On radiological review at five years, one patient had a progressive lucent line around the acetabular component and six had progressive lucent lines around the femoral component. A total of 18 femoral components (8%) had migrated into varus and those with lucent lines present migrated a mean of 3.8 degrees (1.02 degrees to 6.54 degrees) more than the rest. Superolateral notching of the femoral neck and reactive sclerosis at the tip of the peg of the femoral component were associated with the presence of lucent lines (chi-squared test, p < 0.05), but not with migration of the femoral component, and are of unknown significance. Our results with the Birmingham hip resurfacing continue to be satisfactory at a mean follow-up of five years.

Early results of primary Birmingham hip resurfacings. An independent prospective study of the first 230 hips.

We describe the experience with the first consecutive 230 Birmingham hip resurfacings at our centre. At a mean follow-up of three years (25 to 52 months) survivorship was 99.14% with revision in one patient for a loose acetabular component and one death from unrelated causes. One patient developed a fracture of the femoral neck at six weeks which united unremarkably after a period of non-weight-bearing. The Harris hip score improved from a mean of 62.54 (8 to 92) to 97.74 (61 to 100). The mean flexion improved from 91.52 degrees (25 to 140) to 110.41 degrees (80 to 145). Most patients (97%) considered the outcome to be good or excellent. Our preliminary experience with this implant is encouraging and the results are superior to the earlier generation of resurfacings for the same length of follow-up.

Complications associated with hip resurfacing arthroplasty.

Hip resurfacing arthroplasty is an old orthopedic concept that has undergone a resurgence of interest in the past decade. Because of the rapid increase in the number of procedures being performed, previously recognized complications have begun to recur. This article focuses on complications that are related to the hip resurfacing procedure such as femoral neck fractures, avascular necrosis, raised metal ion levels, and sound initial and durable long-term fixation of an all-metal monoblock cobalt/chrome acetabular component. Dislocation rates after resurfacing and other complications are briefly discussed.

Risk of cervical injuries in mixed martial arts.

BACKGROUND: Mixed martial arts have rapidly succeeded boxing as the world's most popular full contact sport, and the incidence of injury is recognised to be high. OBJECTIVE: To assess qualitatively and quantitatively the potential risk for participants to sustain cervical spine and associated soft tissue injuries. METHODS: Four commonly performed manoeuvres with possible risks to the cervical spine were analysed with respect to their kinematics, and biomechanical models were constructed. RESULTS: Motion analysis of two manoeuvres revealed strong correlations with rear end motor vehicle impact injuries, and kinematics of the remaining two suggested a strong risk of injury. Mathematical models of the biomechanics showed that the forces involved are of the same order as those involved in whiplash injuries and of the same magnitude as compression injuries of the cervical spine. CONCLUSIONS: This study shows that there is a significant risk of whiplash injuries in this sport, and there are no safety regulations to address these concerns.

Early results of the Souter-Strathclyde unlinked total elbow arthroplasty in patients with osteoarthritis.

We have carried out a retrospective review of 11 Souter-Strathclyde primary total elbow arthroplasties in ten patients with osteoarthritis, over a period of nine years. The diagnosis was primary osteoarthritis in nine elbows and post-traumatic arthritis in two. The mean follow-up was 68 months (15 to 117). Although no patient was symptomatic, radiological review revealed evidence of loosening affecting three humeral and two ulnar components, one of which subsequently failed and was revised at 97 months. There were no dislocations, deep infections or mechanical failures. Complications included two superficial wound infections and two neurapraxias of the ulnar nerve which resolved. This study shows that the unlinked Souter-Strathclyde total elbow arthroplasty can be considered for patients with osteoarthritis and gives good symptomatic relief and improvement in function.

The Kinemax total knee arthroplasty. Nine years' experience.

We reviewed the outcome of 422 primary cemented Kinemax total knee arthroplasties implanted into 369 patients over a period of five years, from January 1989. The operations were carried out at two NHS district general hospitals and one teaching hospital by 31 surgeons. During the period of review, 49 patients died and ten knees were lost to follow-up (68 knees). The mean Knee Society score improved from 28 before to 89 after surgery, and the mean function score increased from 23 to 79. The range of flexion improved from 92 degrees to 105 degrees. These improvements were maintained throughout the period of study. At the latest review radiolucent lines of 1 mm were seen around 15% of tibial components, 1.4% of patellar components and 9.5% of femoral components. In no case were these changes progressive. Using revision as the endpoint, cumulative survival was 99% after five years and 96.95% after nine years. All revisions were undertaken for deep infection or secondary trauma. Our study has shown that the Kinemax total knee replacement, when carried out with retention of the posterior cruciate ligament by surgeons of varying experience, produces very satisfactory results in the medium term.

The effect of component malalignment on the clinical and radiological outcome of the Kinemax total knee replacement.

Component angles of 198 Kinemax total knee replacements were measured from standard short leg radiographs. An ideal tibio-femoral angle of between 4 and 10 degrees of valgus was achieved in 64.6% of patients. After an average follow-up of 6.5 years (range 4.5 to 9.5), there was no significant difference between knees in acceptable and suboptimal alignment in terms of pre- and post-operative knee and function scores and prevalence of radiolucent lines. Varus placement of the tibial component was significantly more common by trainee surgeons (P<0.001).

Diagnosing shoulder dislocations: time for a change of view.

Posterior shoulder dislocations are uncommon, with frequent delays in the diagnosis. Three missed posterior dislocations within our hospital caused us to review the standard radiographs taken and the knowledge of this condition. A total of 40 radiographers and 40 casualty officers were surveyed. Of the radiographers, 63% felt it unnecessary to perform two views, they complained that laterals were difficult to obtain because of patient distress. All the radiographers surveyed knew of alternative views, but would not perform them unless specifically requested. Casualty officers claimed always to request two views, but did not in 75% of cases. Only 20% were aware of alternative views, all would accept one view for exclusion of a dislocation and none were aware of the radiographic signs associated with a posterior dislocation. Increased education and a change of view would assist in decreasing the rate of missed diagnoses.

Radiation protection for your hands.

A prospective clinical trial was performed to assess the suitability of a new type of sterilisable, user-friendly radiation protection glove. In a preliminary trial, we showed that the dominant hand of the primary operating orthopaedic surgeon receives the highest dose of radiation. During a 4-month period, 98 procedures were done requiring the use of an image intensifier. The doses of radiation to the dominant hand of the operating surgeon were reduced to less than the doses of radiation to the non-dominant hand. The glove was sterilisable, user-friendly and accepted by the majority of surgeons. It offers greater than 90% attenuation of X-rays and is superior to all other scatter gloves on the market.