In 1823 J. White excised the head. In 1887 a German surgeon replaced the head with ivory. Interposition arthroplasties were common after WW1. Short-stemmed head replacing prosthesis were developed after WW2. Moores and Thompson designed a more stable intramedullary stem. Acetabular erosion was troublesome—and so replacing both surfaces started in the late 1950s using Teflon cup and metal femur. Unfortunately, these quickly became loose due to wear or sepsis. In 1960, Charnley used a polyethylene cup and stainless-steel femur and fixed both with dental cement. This ‘low friction arthroplast’ became a routine procedure after 1961. In the 1970s there were many ‘Charnley look-alike’ prosthesis with similar problems of poly-wear, granulomas and cysts causing bone loss, loosening, breakages and infection. Resurfacing with two thin shells was developed to reduce the foreign material, the bone resection and the cement used. Unfortunately, neck fractures, avascular necrosis and excessive wear of the poly shell were common. Despite operating theatres with laminar flow of sterile air, space suits and improved cementing techniques, the same problems occurred. To avoid poly and cement, Mittelmayer developed a ceramic screw cup, which did not require cement. Although some screws migrated, they did not wear. Because the un-cemented metal stem remained fixed solid to the femur, un-cemented metal cups and stems were developed. To avoid the poly-wear, ceramic liners became popular. To provide the active patients with a stable joint that requires no restriction in physical activity, a large head in a large cup is desirable. Unfortunately, the large metal-on-metal resurfacing prosthesis produce metal wear ions and nanoparticles which can form hypersensitivities, cysts and pseudotumours. Computer assisted navigation to ensure correct positioning of the prosthetic components is obviously useful for surgeons that use incisions too small to see enough to be certain of the cups position. Presently, articular cartilage research is progressing rapidly and by 2020 most arthritic hip joints will be arthroscopically debrided and resurfaced by an injection of genetically engineered articular cartilage stem cells.
The Parliament makes the law, the court interprets the law and the judge or jury make the decisions. The adversarial system in Australia is a battle between two advocates who elicit information which is consistent with the version of facts being advanced in his/her case and likely to persuade the court (judge or jury). Deciding on fault is the courts decision. In criminal cases the standard of proof is “beyond reasonable doubt” in civil cases the standard is “on the balance of probabilities” You may be called to court to present the details regarding your patient or as an expert witness. The court needs you because the two parties have failed to agree regarding any of the following; the presence of a clinical problem, the probable cause of the alleged injury, the degree of pain, suffering, loss of performance and expected permanent impairment. The surgeons dilemma is that the patients details are confidential but the discussions in court can become public knowledge. A medical expert is recognized to possess knowledge or experience which is beyond that of the ordinary members of the lay community (or jury). Your evidence is therefore related to a matter that is not ‘common knowledge’. The lawyers are in their comfort zone, you are a fish out of water. The court is their theatre yours is in the hospital. The court needs your evidence.
Don’t try to help to see that justice is done. Use simple and concise language, stick to the facts and your field of knowledge (what you know, heard or saw). Don’t do the advocates job nor try to help or take sides. Don’t be intimidated to answer yes or no when you know that neither is correct. Don’t embellish, dramatize, show off, guess, be evasive, use complicated medical terminology or volunteer opinions. If you believe that the proceedings are ‘way off the mark’ you can appeal to the judge to allow you to make a statement to clarify an issue.
