The Practitioner   November 4, 2004   Key developments in orthopaedic surgery   SECTION: Pg. 775   LENGTH: 2238 words     * How has arthroscopy revolutionised joint surgery? * How are digital cameras and mobile phones improving management? * What advantages do the new bioabsorbable implants offer?  SIMON P FROSTICK BA, BM, MA (Oxon), FRCS (Engl), DM (Oxon)  Professor of Orthopaedics, University of Liverpool  VISHAL SAHNI MS, FRCS (Glasg), FRCS (Trauma & Orthopaedics), M Ch (Orthopaedics)  Specialist Registrar, Royal Liverpool University Hospital  We are witnessing an explosion of treatment possibilities in both elective orthopaedics and orthopaedic trauma. The levels of intervention are increasing, backed by evidence for the efficacy of the treatment choices, availability of appropriate equipment and an improved knowledge about the anatomy, physiology and biochemistry of musculoskeletal pathology.  This increase in our ability to successfully undertake surgical treatment of our patients has inevitably resulted in subspecialisation among orthopaedic surgeons. It is no longer possible for there to be a general orthopaedic surgeon' who dabbles in all aspects of the specialty.  These changes also have a number of implications for GPs. They need to be aware of the special interests of various orthopaedic surgeons at their local hospital. A referral for a said condition should be made preferably to an orthopaedician with a declared interest in that condition. Also, if the local hospital does not cover all subspecialties, in the best interest of patients GPs should be informed of this and provided with a list of subspecialists from the nearby region. * Arthroscopy The majority of soft tissue pathologies in the knee are now treated arthroscopically, but more recently there has been an increase in the use of arthroscopic techniques in other joints, especially the shoulder.  Arthroscopic examinations of joints allow surgeons to closely examine the internal structures. This has revolutionised our understanding of pathological lesions and enabled surgeons to develop new and effective solutions.  In the knee, anterior cruciate ligament repair, meniscal repair and cartilage transfer operations are now relatively common procedures. In the shoulder we now have the ability to undertake nearly all soft tissue procedures arthroscopically.  In the Liverpool Upper limb Unit nearly 100 per cent of shoulder stabilisation procedures are performed using a variety of arthroscopic techniques. A major advantage of this approach is that we can fully assess the type of instability and the type and extent of any structural lesions that are encountered.  Although the diagnosis of the instability is a clinical diagnosis, an arthroscopic approach to the surgical treatment allows us to tailor the procedure to the individual patient and to modify the procedure with ease if any unexpected lesion is found.  Arthroscopy has also highlighted how little we were able to see by open means: for example, a labral tear involving the superior labrum and long head of biceps tether - referred to as a SLAP (superior labrum anterior-posterior) tear - has only been identified since surgeons have performed arthroscopy of the shoulder.  In our experience a SLAP tear is a common cause of shoulder pain and disability, and repair results in an early return to full function.  Since the first report of the SLAP lesion, an increasing number of variations of the tear have been reported. Again it is our experience that there is an almost infinite variety of superior labral lesions, some of which need repair and some debridement. Some of the lesions are associated with anterior dislocations, others exist in isolation and some are probably degenerative in origin.  A spin-off of our understanding of the arthroscopic pathoanatomy in shoulder instability is that we have a much greater understanding of those types of instability that are not associated with any structural lesion except for a loose capsule. In the past these patients would be referred to as habitual dislocators or voluntary dislocators, terms that have little meaning and even less understanding.  Now, however, it is apparent that there is a spectrum of patients who have loose shoulders: at one extreme are patients who have a collagen abnormality such as Ehlers-Danlos syndrome, but there is a much larger population who also have moderately loose shoulders. However, if it is associated with symptoms like pain, a feeling of looseness', weakness and recurrent subluxations or dislocations of the shoulder, they are said to have multi-directional instability.  Approximately 80 per cent of these patients benefit from physiotherapy and rehabilitation, while in the remaining 20 per cent arthroscopic capsular shrinkage (ACS) may have a role.1,2 In ACS the looseness of the capsule is reduced by heat at a specific temperature, delivered through the end of a probe to shrink the capsule. * Minimally invasive joint replacement In the last five years or so minimally invasive surgery has become headline news and joint replacements carried out using small incisions have been very much in vogue. In the case of hip replacement the incision is just over 7cm long rather than the 20-30cm incisions seen in conventional hip replacement surgery - and some surgeons now prefer two even smaller incisions.3  More importantly the surgeon gains access to the joint by going between muscles, tendons and ligaments, rather than cutting through these soft tissues.4 Much of the pain associated with conventional hip replacement surgery and recovery is due to severing these tissues, and so post- operative pain in minimally invasive surgery is considerably reduced. Further, patients can get up and walk sooner, their rehabilitation time is faster and they return to their everyday activities much more quickly. Hip replacement as a day-case procedure is now on the horizon.  In the last few years our laboratory-based research and clinical knowledge have improved our understanding of joint replacements and why and how they fail. This applies equally to joints of the upper limb.  From small joints of the hand to the shoulder joint, almost all joint replacements of the upper limb are now established, but we are still constantly seeing and seeking improvements and new designs as well as searching for better bearing surfaces. Anaesthetic and surgical techniques have also developed. There is now no justification for allowing a patient with significant arthritis to suffer with pain, and early referral in such cases is desirable.  Regional blocks and advanced anaesthetic techniques have allowed us to reduce our dependence on general anaesthetic, which has meant that fewer patients have to go through post-operative in-patient observation.  A shorter incision and bone conserving resurfacing arthroplasty, such as the Copeland hemiarthroplasty for the shoulder, may mean that in the near future the Liverpool Upper Limb Unit might offer patients shoulder replacement as day-case surgery - until now, patients have been kept as inpatients for up to 7-8 days. Costs will be reduced, and patients will be returned to their home environment much more quickly, which most of them desire. * Digital imaging and transfer The use of digital imaging by digital cameras or mobile phones in orthopaedics has helped patients and doctors alike. Mobile phones with high-resolution cameras are used to transmit radiographs to off-site consultants to allow them to give advice regarding management.  It is envisaged that this scheme can include GPs and if so, it should benefit the patient greatly by making specialist advice available to them instantaneously.  As the specifications and clarity of imaging continues to improve, the use of this ingenious method may increase even further. * Robotic surgery and computer-assisted surgery Both robotic surgery and CAS are now in use on an experimental basis for total knee replacement in some NHS hospitals and show some promise with regard to precision.5 However, they will have to be evaluated rigorously for cost- effectiveness, increased operative time, learning curve and actual benefit to the patient.  The robot assists the surgeon in performing the surgery rather than performing the surgery itself. In conventional knee replacement, a surgeon uses specialised cutting blocks, eyeballing', feel and experience to make appropriate bone cuts for the best fitting of an implant.  Once a cut is made the bone cannot be replaced and hence the carpenter's advice measure twice, cut once' is vital in knee replacement surgery.  Robotic surgery and CAS use infrared cameras, digitalised bone images and simple tracking devices to achieve alignment within 2deg and 2mm of total accuracy.  The potential benefits to the patient are reduced risk of fat embolism as an intra-medullary rod is not used, and accurate alignment and placement of the implant may extend its lifespan. Also, better vision' may allow shorter incisions and minimally invasive surgery. * Biomaterials Many surgeons are now moving towards using devices made from bioabsorbable polymers such as polylactic acid (PLA) and polyglycolic acid (PGA), including interference screws, suture anchors and meniscal repair devices.  Bioabsorbable implants offer several advantages over their metallic counterparts: * Secure initial fixation strength while allowing degradation * Magnetic resonance imaging (MRI) is not distorted * Easier to revise because there is no need for implant removal prior to revision surgery * Though not visible on radiographs, visible with MRI  In recent years suture anchors have become popular for both open and arthroscopic repairs of avulsed ligaments or tendons, most commonly for Bankart and rotator cuff repairs.  A knotless suture anchor is another step forward and obviates the need for arthroscopically-tied, time-consuming and bulky knots. A knotless suture anchor obviates the need for arthroscopic knot-tying while providing a direct, secure, low-profile suture anchor repair.6  In the Liverpool Upper Limb Unit the use of knotless anchors has reduced surgical time and increased the efficiency of the Unit. * Technological fiascos Orthopaedics has been quick to embrace new technology, but new technologies are not always without their faults. Two recent incidents involving technological problems with the 3M Capital Hip System and the Sulzer Hip System have put surgeons in a sombre mood and reinforced the conviction that if new technology is to be used, checks and balances must be applied with equal enthusiasm.7,8 * The 3M Capital Hip System In 1998 a hazard notice was issued by the Medical Devices Agency UK9 after poor short-term performance of the femoral component of the 3M Capital Hip System was noted.  Between 1991 and 1997 the number of 3M Capital Cemented Hip Systems (Capital Hip) sold to hospitals in the UK was 4688. The health authorities were advised to recall all patients who had undergone the 3M Capital Hip System for clinical and radiological review. It asked for consideration of revision surgery if the patient had evidence of loosening of the femoral component.  A subsequent enquiry after reviewing data on 3700 implants concluded that the poorer performance of the Capital Hip, had it been analysed separately, would have been apparent by the end of 1993, long before 1998. * The Sulzer Hip System in USA A similar situation involved the Sulzer Inter-Op uncemented acetabular implant, which was a part of the Sulzer Hip System. A manufacturing error in the production left a machine oil residue on the implant that prevented it from bonding to the patient's bone, and this forced the company to recall nearly 25,000 hip implants. Unfortunately nearly 17,500 of these had already been implanted in patients.  Due to this error a large number of patients who had this cup implanted would require or already underwent a revision hip operation, thereby increasing morbidity and mortality.  References  1 Lo IK, Bishop JY, Miniaci A, Flatow L. Multidirectional instability: surgical decision making. Instr Course Lect 2004;53:565-572  2 Frostick SP, Sinopidis C, Al Maskari S et al. Arthroscopic capsular shrinkage of the shoulder for the treatment of patients with multidirectional instability: minimum 2-year follow-up. Arthroscopy 2003;19(3):227-233  3 Berger RA. The technique of minimally invasive total hip arthroplasty using the two-incision approach. Instr Course Lect 2004;53:149-155  4 Siguier T, Siguier M, Brumpt B. Mini-incision anterior approach does not increase dislocation rate: a study of 1037 total hip replacements. Clin Ortho 2004;426:164-173  5 Siebert W, Mai S, Kober R, Heeckt PF. Technique and first clinical results of robot-assisted total knee replacement. Knee 2002;9(3):173-180  6 Yian E, Wang C, Millett PJ, Warner JJ. Arthroscopic repair of SLAP lesions with a bioknotless suture anchor. Arthroscopy 2004;20(5):547-551  7 Guidance on the selection of prostheses for primary total hip replacement. National Institute for Clinical Excellence, London: NICE, 2000 www.nice.org.uk  8 Total hip replacement: A guide to best practice. London: British Orthopaedic Association, 1999. www.boa.co.uk  9 3M Capital Hip System; The lessons learned from an investigation. London: The Royal College of Surgeons, 2001   LOAD-DATE: November 8, 2004   LANGUAGE: English   PUB-TYPE: Magazine   Copyright 2004 CMP Information Ltd