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View my account settingsThere is little in the recent literature about the place of low molecular weight heparin (LMWH) in routine lumbosacral surgery.
This study aimed to determine firstly the risk of deep vein thrombosis (DVT) if Clexane was not given preoperatively, and secondly the complications associated with the use of the drug.
In a prospective study undertaken from January 2001 to April 2001, 64 patients scheduled for routine lumbosacral surgery were entered. We excluded patients with a high risk of DVT. The mean age of patients was 51 years (16 to 75). Patients were randomly selected to receive Endoxaparin (Clexane) preoperatively the night before (38 patients in group 1) or Clexane postoperatively (26 patients in group
2). All patients were evaluated by Doppler sonography pre-operatively, four days postoperatively and at six weeks. Blood loss was monitored intra-operatively and postoperatively. Clexane was administered only for eight days. Posterior lumbosacral spinal procedures only were done on 44 patients, while seven had combined anterior-posterior surgery and 13 anterior procedures only.
Mean intra-operative and postoperative blood losses in group 1 were twice those in group 2, and patients in group 1 tended to bleed for longer. Two cases of partial thrombosis were seen, both group 1. In group 1 intraspinal haematoma formation was seen in four patients, two of whom required additional surgery.
LMWH should not be given preoperatively for routine spinal cases. In fact, it is contra-indicated.
A retrospective study was done on the outcome of supracondylar femoral fractures treated with retrograde or supracondylar intramedullary nails.
Between January 1998 and December 2000, 69 patients were treated with Russell Taylor nails, 30 at Kalafong Hospital and 39 at Pretoria Academic Hospital. Injuries had resulted from motor vehicle accidents in 27 patients, from falls in 32 and from gunshots in 10. There were 13 open fractures and 14 patients had multiple injuries, including three head injuries and two vascular injuries. Using the AO classification, 40 fractures were graded type A and 29 type C. The mean age of the 18 female and 51 males was 45 years (17 to 90). Senior registrars performed the surgery. In all cases, the knee was opened for the procedure. Four patients died from their injuries.
The mean time to union was 13 weeks. Four patients had poor range of motion. Complications included two cases of superficial sepsis and three of deep sepsis. There were two cases of delayed union and three of fixation failure. In one patient the fixation impinged on the patella.
We find this a good way of treating supracondylar femoral fractures.
The worldwide increase in the resistance of micro-organisms to antimicrobial drugs leads to an increase in morbidity, mortality and health care costs. It is important to identify the resistant organisms, to provide alternative antibiotic treatment protocols and to identify the high-risk infection areas.
We undertook a retrospective study of 693 musculoskeletal infections seen in the Musculoskeletal Tumour and Sepsis Unit of Pretoria Academic Hospital over five years, capturing data relating to the microscopy, culture and sensitivity to antimicrobial drugs of micro-organisms from tissue samples and pus swabs.
Most infections developed in patients aged 31 to 40 years. Sepsis most often occurred postoperatively. The next most common sepsis followed trauma. The femur was the most common site, followed by the tibia and the knee. In descending order, the most common organisms isolated were Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas sp., Escherichia coli, Enterobacter sp.
In the last two years there was an alarming increase in coagulase-negative staphylococci. All micro-organisms exhibited increased resistance to specific antimicrobial drugs over the five-year period.
During the last four years the author has used extracorporeal shock wave therapy (ESWT) to treat tendonoses, including 82 cases of tennis elbow, 108 cases of plantar fasciitis and 42 cases of related conditions. Treatment is administered in the consulting room without analgesia. This paper discusses the protocol used in selected cases.
In 78% of cases, overall subjective and objective results were good to excellent, in 15% fair. In only 17% was the result poor, with no improvement. No cases of degeneration were encountered. There were few complications and these were minor. Because of the obvious clinical benefits in selected cases, this new modality of orthopaedic treatment is still being used daily after four years.
Osteoarthritis of the hip exhibits progressive degeneration of articular cartilage frequently resulting in total hip arthroplasty (THA). Expression of cytokines such as tumor necrosis factor alpha (TNF-alpha) and interleukin 6 (IL6) is increased in the synovium and articular cartilage of these patients. Furthermore, these cytokines have been shown to have a negative regulatory effect on chondrocyte proliferation and articular cartilage metabolism. We investigated the frequency of a G/C polymorphism at position −174 of the promoter region of the IL-6 gene and a G/A polymorphism at position −308 of the TNF alpha gene, both of which cause increased expression of these cytokines. We observed that the G variant of the IL6 gene was significantly higher in patients who had undergone revision THA compared to controls (P=0.05). It was also elevated in primary THA patients compared to controls. The G/A polymorphism in TNF alpha was not significantly associated with THA; however, this may reflect the lower incidence of this polymorphism in the population. These results suggest that an alteration in cytokine expression produced by the IL6 −174G/C mutation may have a role in the aetiology of osteoarthritis and the outcome of total hip arthroplasty.
A non-invasive technique for labelling S phase osteoblasts in vitro following immunolabelling of their focal adhesions is proposed. Quantification of cell adhesion area in the S phase (where the cells are most spread) of the cell cycle is then possible with a scanning electron microscope (SEM).
Primary calvarial osteoblasts (isolated by migration) were cultured on plastic and implant quality metal discs. S-phase cells were labelled by a pulse of 3H thymidine in the culture medium for 30 min. Cells were cultured for a further 2h in normal media before being processed for immunogold labelling of vinculin. Briefly, cells were permeabilised and fixed in 4% paraformaldehyde. Non specific binding sites were blocked for 30 min. Cells were incubated with mouse anti vinculin for 1h before rinsing and blocking with 5% goat serum for 30 min. Secondary incubation was with goat anti mouse 5nm gold conjugate for 2h. After rinsing, cells were permanently fixed with 2.5% glutaraldehyde. For SEM visualisation, the gold label was enhanced with gold enhance solutions. Postfixation and staining was performed with osmium tetroxide. Samples were dehydrated and critically point dried. The discs were carbon coated and covered with a thin layer of photographic emulsion in a dark room and left in a light tight box at 4°C for 7 days before developing the emulsion.
Backscattered electron imaging with the SEM revealed silver grains on the nuclei of S-phase cells, produced by the interaction of radioactive emissions, from the labelled DNA, and the photographic emulsion. Immunolabelled focal adhesions were also observed at higher magnifications on the same cells.
This combination of autoradiography and high resolution SEM removes cell cycle variability, which has been a problem with previous in vitro adhesion studies. This method will be applied to quantify osteoblast cell adhesion to various implant materials to evaluate cell/implant interactions.
The changes occurring in ligamentum flavum in lumbar spine stenosis are a matter of long–standing controversy. More recently, some studies showed that the posterior spinal structures, including hypertrophied ligamentum flavum, play a major role in the pathogenesis of the lumbar stenosis.
To investigate the pathogenesis of the degenerative changes of the ligamentum flavum occurring in lumbar spine stenosis, yellow ligament cells from patients with lumbar spine stenosis were cultured for the first time and subjected to biochemical, histochemical and immunohistochemical study.
Samples of ligamentum flavum were collected from 4 patients undergoing surgery for lumbar stenosis (mean age 47.2 years). Cell cultures were obtained from each patient and maintained in Dulbecco’s modified essential medium-10% fetal calf serum. Cell characterization was histochemically (Gomori’s and von Kossa staining), immunohistochemically (anti-type I, -type II, -type III and -type X collagen, anti-S100 protein, anti-fibronectin, anti-osteonectin and anti-osteocalcin), biochemically (cAMP activity after human parathyroid hormone stimulation) assessed. Samples collected from 2 age-matched patients who underwent surgery for lumbar fractures were used as controls.
Stenotic ligamentum flavum cells expressed high levels of alkaline phosphatase activity and produced a mineralized matrix rich in type I, type III and type X collagen, fibronectin, osteonectin, and osteocalcin. Stimulation with parathyroid hormone increased intracellular cAMP concentration. These findings indicate that there was significant evidence of osteoblast-like activity in these cells. Staining for type II and type X collagen, and S-100 protein reflected the proliferation of hypertrophic chondrocyte-like cells, confirmed with the co-localization of alkaline phosphatase and collagen type II. Cultures from control patients showed nor hypertrophic chondrocytic nor osteoblastic features. Our data demonstrated the presence of hypertrophic chondrocytes with an osteoblast-like activity in human stenotic ligamentum flavum. The osteoblast-like activity could have a role in the pathophysiology of the heterotopic ossification of ligamentum flavum in lumbar spine stenosis.
The purpose of this study was to evaluate the safety of liquid collagen and cross-linked collagen in treating bone defects.
In a prospective trial, the use of liquid collagen and a stiffer, slightly more rigid cross-linked collagen allograft was evaluated. Bone cavities resulting from curettage of cysts or tumours were filled with either liquid or cross-linked collagen. The collagen was extracted from donor allograft and mixed with minute particles of crushed cortical bone. Patients were monitored clinically, radiologically and haematologically for complications, including infection, rejection or allergic reactions.
There were five patients with osteoid osteoma, five with chondrosarcoma, two with bone cysts, five with osteitis and three with chondroblastoma. One patient each had enchondroma, ossifying fibroma, osteosarcoma, aneurysmal bone cyst, fibrous dysplasia, thickening of the tibial cortex, avascular necrosis, Ewing’s sarcoma, a luxstacortical ganglion and a tumour of the pubic symphysis. Eleven patients received liquid collagen and 32 cross-linked collagen. The use of liquid collagen was abandoned because it was too fluid to keep in the cavity. The cross-linked collagen, though more solid, could be introduced even through small holes in a bone or spinal cages. No allergic reactions occurred and the bone graft behaved similarly to a combination of allograft/autogenous graft.
Cross-linked collagen is as effective as any other allogenic bone product in bone cavities. In this series there were no complications attributable to the graft.
PMN Migraoty Activity: PMN were isolated from citrated blood at admission, 8 and 24 hours later. The number of PMN migrating across porous tissue culture inserts in response to defined concentrations of IL-8 (zero, 10, 30 & 100ng/ml) were quantitated by peroxidase assay.
Fractures and fracture dislocations involving the lower lumbar spine and lumbosacral junction are uncommon. These high velocity injuries are often associated with neurological deficit, incontinence and dural tears. The accepted treatment has been posterior stabilisation with fusion, but loss of reduction has often been reported.
We reviewed our experience over the past four years in the management of eight male patients, two of whom sustained injuries in motor vehicle accidents and two in falls from a height. Two patients had L5/S1 traumatic spondylo-listhesis with no neurological deficit. Of the six patients with fracture dislocations of L3/4, four had translation in the sagittal and coronal planes and incomplete neurological deficit. Associated injuries in four patients included an ankle fracture, multiple rib fractures, dislocation of knee and hip, and a fracture dislocation of the midfoot.
Following satisfactory reduction, seven patients were treated by posterior spinal fusion (PSF) with instrumentation. One patient had anterior decompression, strut-grafting and posterior instrumentation. Three patients had dural tears.
In three patients treated by single segment PSF, reduction was not maintained. The maintenance of alignment was attributed to stable facet joints in one patient, two-segment instrumentation in three, and anterior strut grafting in one. One patient developed postoperative wound sepsis, which settled after repeated debridement and antibiotic treatment. Symptoms of nerve root compression improved in two of the four patients with neurological deficit.
Posterior reduction and instrumentation alone did not maintain reduction in these severe injuries. Anterior column support and multisegmental instrumentation may be required where there is marked vertebral body compression and neurological deficit.
Systematic reviews show beneficial effects of spinal manipulation, general exercise, and ‘active management’. A national randomised factorial trial in primary care (UK BEAM trial) was designed to evaluate the effectiveness of these treatments for back pain. We will present the characteristics of participants recruited into the trial and preliminary health outcomes at one and three months.
Back pain patients, recruited from over 150 UK practices, were randomised to receive GP management, exercise classes, manipulation (either in NHS or private premises) or both manipulation and exercise classes. At one, three and twelve months, participants completed postal questionnaires which included questions about general health, experience of back pain, beliefs about back pain, psychological profile, functional disability and costs to both the NHS and the participants themselves.
The trial recruited 1334 participants, of which 84% and 77% completed one and three month questionnaires respectively. At randomisation, the mean Roland Disability Questionnaire (RDQ) score was 9.0 points (sd=4.0). This improved to 6.8 points (sd=4.8) at one month and to 5.5 points (sd=5.0) at three months.
Preliminary blinded results show an improvement in RDQ scores across all participants. The primary analysis, available late in 2002, will estimate the main effects of exercise and manipulation, each compared to GP care.
The retraction of the triceps surae was measured from the maximal passive dorsal flexion angle of the foot, before and after applying each stretching boot. The difference between these measurements gave the gain obtained with the plaster boot. Protocol R− (stretching with plaster boot) consisted in a series of slow stretchings for 10 minutes before making the boot which was worn 7 days. Recurrent retraction in these same patients warranted another treatment within a delay of 3 to 17 months (mean delay 8.7 months). The same treatment then followed protocol R+ where the stretching was preceded by immersion of the segment in a 40°C water bath for 10 minutes.
The success of lumbar spine fusion depends on good patient selection and bone grafting technique. Instrumentation of the fusion, now popular, improves fusion rates, eliminates the need for postoperative braces and allows early mobilisation. However, the stress shielding caused by rigid internal fixation is thought to lead to osteopoenia and degeneration of adjacent segments. Theatre times, intra-operative complications and costs are increased when pedicle screw fixation is added.
This is a report of a pilot study of eight patients who had one-level fusion and unilateral instrumentation between 1998 and 2000. Theatre time, fusion rate and functional outcomes were evaluated. The minimum follow-up time was eight months. Fusion was achieved in all patients and there was no metal failure. One patient continued to have back and leg pain in spite of a solid fusion.
Although this is a small study undertaken over a short period, the results suggest that unilateral pedicle screw fixation can be safely undertaken.
We looked at the outcome of management of 16 patients (19 limb segments) with congenital fibular hemimelia treated in our unit over a 24-year period from 1978 to 2001. Eight boys and eight girls, all with associated musculoskeletal abnormalities in the lower limbs, were presented for management at or before the age of six months.
On four patients no surgery was performed. In the other 12, orthopaedic management was completed during the skeletal growth period. Primary amputations (one below-knee, one Syme and one Boyd) were performed on three patients and prostheses fitted in early childhood. Three patients with bilateral fibular hemimelia were treated initially with a Gruca ankle reconstruction procedure. Using the Ilizarov technique, we performed tibial lengthening procedures on nine patients.
At the latest follow-up, the three patients who had amputations were functioning well and had no complications. The nine patients in whom tibial lengthening was the main reconstructive procedure suffered numerous complications and all needed further corrective surgery or footwear alterations. None required or requested late amputation because of poor function or cosmesis. Analysing results by parameters such as restriction of activity, pain, complication rate, treatment costs, hospital and clinic visits, periods of absence from school, and patient satisfaction, we found notably better results among patients who underwent early primary amputation than among those who underwent tibial lengthening.
This needs to be kept in mind when advising parents of the most appropriate course of management of their child’s disorder.
Injury to the infrapatellar branch of the saphenous nerve has been reported as a complication of arthroscopic examination and surgery of the knee. This can result in altered sensation on the anterolateral aspect of the knee, reflex sympathetic dystrophy and, occasionally, severe deafferentation pain. The aim of this cadaveric study was to delineate the course of the infrapatellar branch as it passes across the anterior aspect of the knee and identify potential safe areas for blind puncture at arthroscopy. The risk of damage to the nerve branch from the various open incisions used for orthopaedic surgery of the knee is also discussed.
The distribution of the infrapatellar branch was studied in both lower limbers of eleven cadavers (22 specimens). Two patterns of nerve distribution could be described in relation to its path across the proximal margin of the tibia. In 28% of examined cadavers, the infrapatellar branch of the saphenous nerve traverses the patellar tendon and runs laterally without ever crossing over the tibia. In the remaining 72% the infrapatellar branch crossed the proximal margin of the tibia prior to crossing the patellar tendon. Using the interior pole of the patella as a landmark, our results indicated that blind puncture is safe within an approximate wedge-shaped area ranging from 10mm inferior and 30mm medial to the inferior pole up to a level 10mm superior and 50mm medial to the inferior pole of the patella. The incidence of injury to this nerve can be reduced by clarifying the distribution of the infrapatellar nerve branch in relation to palpable landmarks.
Between 1997 and 2000, internal arthrodiastasis procedures (endo-apparatus), using an internal skeletal distraction device, were performed on 33 young patients who had reached the point of total hip arthroplasty or arthrodesis.
The mean age of the 20 males and 13 females was 19 years (range 11 to 51 years). We removed 19 implants, eight after completion of treatment or because they had outlived their usefulness, and 11 because no improvement in the hip disorder had been achieved.
Good results were achieved in two thirds of the patients, including patients suffering from avascular necrosis of the femoral head, old Perthes’ disease and contained hip dysplasia with joint space narrowing and pain. Chondrolysis and stiffness of the hip appear to be contraindications for this type of treatment. The three post-traumatic hip disorders were probably also not ideal cases.
In young patients, the results of total hip arthroplasty after trauma are poor, and the indications for internal arthrodiastasis should be redefined.
The effects of infection following implantation of an orthopaedic prosthesis are devastating. The prevention of perioperative contamination is therfore of the utmost importance in arthroplasty. We undertook a prospective study to assess bacterial contamination in elective arthroplasty surgery. Splash bowls containing sterile saline are used to store and clean instruments used during the course of a procedure. The incidence of bacterial proliferation in splash bowls was examined as a marker of intra-operative contamination. A 100mL aliquot of fluid was removed from the splash basin at the end of the procedure and passed through a grid membrane using a vacuum pump. The membrane filter was then plated on chocolate agar and colony counts recorded at 24 and 48 hours. Organisms were identified by standard techniques. Demographic data, and perioperative data including the duration and type of procedure, the number of scrubbed and other personnel in theatre and the type of skin preparation and gowns used were also noted. A total of 43 cases were examined. 14 samples yielded positive cultures. Staphylcoccus was the most commonly cultured organism (9 cases). Four patients grew Pseudomonas species. Five patients grew other Gram-negative organisms including Neisseria and bacillus subspecies. Five patients grew multiple organisms. Mean duration of follow up was 8.4 months (range 6 – 18 months). None of the patients with contaminated samples developed any clinical signs of infection in the perioperative period; nor was there clinical or radiological evidence of infection or loosening on subsequent follow up. Despite the use of a laminar airflow system in all cases, in excess of 30% of cases were contaminated. This study underlines the importance of adhering to rigorous protocol in theatre including minimising theatre traffic and the use of antibiotic prophylaxis.
We reviewed 351 cases of nonunion treated between 1987 and 2000. The principles of management included restoration of alignment, stabilisation and stimulation. More recently we used distraction and bone transport, bifocal techniques, single stage lengthening and correction of soft tissue contractures.
The ununited fractures resulted from trauma in 319 cases and in 32 were the sequelae of planned surgery. There were 159 atrophic, 89 hypertrophic and 103 infected nonunions. Nonunion occurred in the tibia in 162 patients, in the femur in 51 and in the upper limbs and other smaller bones in the rest.
At the time of this review, nine patients had abandoned treatment and 25 fractures remained ununited. Amputation had been performed on 20 patients, two at the request of patients with intractable pain, 14 following infection and four because of atrophy. Union was achieved in 297 cases (85%), including 90% of the atrophic, 89% of the hypertrophic and 73% of the infected nonunions. We found no statistically significant difference between the results of patients who smoked and non-smokers, but patients who smoked heavily healed more slowly.
We treated 133 traumatic posterior dislocations surgically between July 1994 and March 2001. In 16 patients, labral tears had occurred.
Operating on posterior hip dislocations, initially we fixated the posterior wall with screws and/or buttress plate, depending on the size of the fragment, and did suture the torn labrum, relying rather on the buttress plate or intact posterior wall for stability.
We began repairing the torn labrum when we realised that any small fragments still attached to the labrum simply pull out from under the buttress plate, allowing the hip to redislocate. Once the wall has been reconstructed, interrupted sutures are passed through the labrum, with the hip internally rotated to prevent shortening of the capsule when sutures are tied. A one-third tubular plate is placed over the sutures lying on the posterior wall and fixed with screws. The sutures are then tied individually over the plate. Postoperatively the patient is kept in bed for six weeks, with the hip abducted and knee extended.
Seven patients in whom the labrum was not repaired experienced redislocation. We performed second operations on two of them, repositioning the plates and reconstructing the posterior wall, but redislocation again occurred. The redislocated femoral heads were damaged because they rubbed against the plate and screws. In the other nine patients, we sutured the labrum, and in a 3 month to 2.5 year follow-up, no redislocation has occurred. .
Labral repair restores stability, and tying interrupted sutures over a buttress plate is an easy and effective method of repair.
We report a case of an aneurysmal cyst localized in the patella of a 37-year-old man. The lesion was secondary to a chondroblastoma at six years follow-up after initial curettage and bone graft. It were no recurrence. Treatment of aneurysmal cysts depends on the degree of articular involvement. We made a detailed study of 11 cases of this rare localization of aneurysmal cysts reported in the literature.
Tuberculosis of the spine is very common and it is important to do confirmatory testing.
This retrospective study involved 40 patients in whom tuberculosis of the spine was diagnosed after clinical examination and investigations. All underwent decompression of the spine for neurological fallout. Intra-operatively, histological tissue, MCS and polymerase chain reaction (PCR) were assessed. PCR was positive in only 50% of the patients, but was complementary to histology and MCS.
We present an original method for the treatment of neglected Monteggia fractures using the Ilizarov technique. This method allows reduction without accessing the radial head by progressive ulnar lengthening after proximal subperiosteal osteotomy of the ulnar bone. We used this method in a six and a half year old girl and achieved excellent radiographical and functional results with normal joint amplitudes. In our opinion, the quality of the outcome is related to the progressiveness of the bone lengthening enabled by this technique which allows restoration of the ulnar length, preservation of the axes of both forearm bones, and controlled reduction of the radial head.
Fundamental engineering considerations indicate that micro-movement of the components of any hip arthroplasty is inevitable: stress cannot exist without strain and vice versa. Micromovement can be classified either as inducible recoverable movement that takes place between the weight-bearing and non-weight-bearing phases of each stride, or as non-recoverable displacement between successive loading cycles.
Radiostereometric analysis is now sufficiently advanced to clarify migration and its significance, and is beginning to throw light on the extent and significance of recoverable cyclical micromovement. We discuss the value of radiostereometric analysis in identifying, early in their in-service life, implants that are likely to loosen.
Leakage after simple suture repair of rotator cuff tears depends on the overall preoperative fatty degeneration index (FDI) of the muscles and preoperative fatty degeneration (FD) of the infraspinatus. When the FDI is = 2, cuff leakage is always observed after repair. The risk of recurrent tears of the supraspinus is high if the FD of the infraspinatus is > 1. However if the FDI is very low or nil, the rate of recurrent tears is 15%. These tears can be explained by tension on sutures in macroscopically and histologically abnormal tendons.
Conclusion: Despite the almost constant need for plasty, rotator cuff repair using sutures without tension after resection of macroscopically abnormal tendon stumps gives, for an equivalent preoperative degree of fatty degeneration and an equivalent number of tendon repairs, better anatomic results than simple suture.
This paper reviews the causes of chronic instability after total hip arthroplasty (THA).
The overall reported incidence varies from 0.5% to 9.5%. At 2% to 6%, the incidence following primary THA is higher with a posterior approach than with an anterior approach (0.5% to 3%). The incidence is reported to be as high as 22% after revision THA and 50% after extensile triradiate approach for pelvic discontinuity.
Inadequate soft tissue lengthening, damaged abductors and nonunion of trochanteric osteotomy are known to predispose patients to chronic instability after THA. Elderly women are particularly susceptible. Poor patient compliance is also a cause.
Surgical technique is also a factor. The lateral decubitus position often causes flattening of the lumbar lordosis, leading to potential cup retroversion. Over 90% of all dislocations are posterior, and disruption of external rotators and capsular damage should be repaired if possible. The optimal implant position appears to be 40° TO 45° of abduction, 15° to 20° of femoral anteversion, and 20° to 30° of cup flexion. Elevation of the hip centre weakens abductor pull, causing instability. Because a reduced femoral offset causes potential instability, this should be measured preoperatively to make sure that the stem can provide adequate offset. It may be necessary to add a thicker liner to increase the offset.
Prosthetic factors which play a role in chronic instability include the use of smaller femoral heads, thick necked stems and heads with skirts. A larger femoral head increases stability simply by increasing the radian about the hip centre, increasing the potential range of motion. Extended posterior wall-adds improve the range of motion, and consequently the stability. However, there are fears that their use may increase the incidence of impingement and/or lead to increased wear. Skirted femoral heads impinge on the liner, limiting movement, and their use should be avoided in most cases of instability.
Femoral stem offset relates to the neck shaft angle and the effective hip centre/shaft axis length or offset. It is easier to increase offset with lower neck shaft angle than to lengthen the leg. Because a bell curve is used in the design of femoral stems, many prosthetic systems lack adequate offset, especially when larger stems (48 mm to 52 mm) are used.
In earlier prosthetic designs, bulk was added to the necks to eliminate stem breakage. In certain stems, the way in which dimensions were scaled meant the neck dimensions of larger prostheses were disproportionately big. We stopped using Depuy Stability stems sizes 16 mm and 18 mm because of this. Thornberry et al have shown that a circulotrapezoidal neck design is the best shape and leads to the least impingement. They have also shown that increasing the width of the chamfer of the acetabular liner rim improves the range of motion.
In treating early instability (occurring less than 30 days postoperatively) most authors recommend bracing for six to eight weeks and warning patients severely about the long-term potential of redislocation. In cases of chronic instability (occurring more than 30 days postoperatively) all potential problems must be explored: these include soft tissue laxity, cup retroversion, inadequate offset, surgical approach, etc. In managing multiple dislocation, the use of extended immobilisation is less desirable although patients who have undergone revision have been subjected to a great deal of soft tissue dissection and potentially should be braced for up to 12 months. If the cause is correctable-malpositioning, soft tissue laxity or bony impingement – treatment is likely to be successful in 85% of cases. However, if the implants are in good position, the ‘bloodless revision’ (Fehring) has less than 50% chance of succeeding. The implication is that an extended posterior wall liner, longer modular femoral head, and soft tissue reconstruction are not going to work in the majority of cases.
Designed by Noiles, the J& J SROM constrained acetabular liner uses a polyethylene capture mechanism that is secured by two additional screws. The pullout strength of this device is 1 350 N but torque required (lever-out strength) diminishes to 17.3 N.m for a 28-mm head. With a 32 mm head, 105° of flexion was obtained (while the normal hip needs up to 113° for usual flexion). Following up 21 patients with this implant for over two years, Anderson et al found redislocation in 29%. The only causative factor identified was an abduction angle of more than 70°. However, there were no cases of implant loosening of this device. Prevention of loosening was one of the design goals in using a ‘softer’ locking mechanism. Dislodgement of the liner requires immediate re-operation.
The Osteonics constrained liner cup has a dual socket. The inner socket has a polished chrome surface manufactured fit to the outer socket. It fits a 22 mm or 28 mm head, and has a locking ring identical to the bipolar implant that holds the head in place. The implant can be snap-fitted into a 52-mm or larger Osteonics cup. This liner can also be cemented into another metal-backed liner. Goetz et al evaluated 56 cases, in 10 of which this implant had been cemented and in 46 lock-fitted in appropriately matched metal shells. In one case, the cemented constrained liner had separated from the metal shell. None of the constrained liners had separated from the metal shells, but one shell had loosened.
There are many similar constrained acetabular liners. The choice is between a ‘locked’ liner that can never separate and a ‘softer’ lock that may protect fixation of the cup.
Hypertrophy of lumbar articular facets and dorsal joint capsule are well documented in degenerative instability, the molecular changes occurring in the extracellular matrix (ECM) are however unknown.
The L4/L5 posterior articular complex was removed from seven individuals undergoing fusion for degenerative instability. After methanol fixation and decalcification in EDTA, specimens were cryosectioned at 12 μm and immunolabelled with monoclonal antibodies for collagen types I, II, III, V and VI; chondroitin-4 and 6 sulphates; dermatan and keratan sulphate; versican, tenascin, aggrecan and link-protein. Antibody binding was detected using the Vectastain ABC ‘Elite’ kit. Labelling patterns were compared to corresponding healthy specimens examined previously.
In comparison, the degenerative capsule was more dense and hypertrophied and the enthesis more fibrocartilaginous, with immunolabelling extensive for collagen type II, chondroitin–6-sulfate, chondroitin-4-sulfate, aggrecan and link-protein. The articular surface showed extensive evidence of degeneration, while the thickened capsular entheses encircled the articular facets dorsally. Bony spurs capped with regions of cartilaginous metaplasia were prominent in this region, the ECM labelling strongly for type II collagen and chondroitin-6-sulfate.
The hypertrophy of lumbar facet joints subject to instability of the functional spinal unit therefore appears to be due to proliferation of the capsular enthesis rather than the actual articular facet. In view of the physiological function of the dorsal joint capsule as a wrap-around ligament in assisting the limitation of axial rotation, the molecular changes found in degenerative instability suggest rotational instability, such as results from degenerative disc disease, to be a decisive factor in the development of spondylarthropathy. It is furthermore probable, that the pronounced sagittal joint orientation in degenerative instability is the result of reactive joint changes rather than a predisposing factor of instability.
Total knee arthroplasty (TKA) is done primarily for pain relief, and function improves when there is less pain. Greater understanding of the biomechanical functioning of the knee has led to an improvement in prosthetic implants. Surgical technique, which plays an important role in the overall outcome of TKA, has also improved over the years. Simultaneous bilateral total knee arthroplasty (SBTKA) is one of the latest techniques employed by arthroplasty surgeons. SBTKA has advantages and disadvantages, and there are clearly diverse reactions to it from surgeons treating patients with bilateral osteoarthritis.
We reviewed 87 patients who underwent SBTKA and compared complications, costs and functional results with those of patients who underwent staged TKA. The same surgeon performed all the operations. There was strict adherence to a consistent preoperative, intraoperative and postoperative protocol.
Our results showed that the complications of SBTKA are not significantly different from of staged TKA. SBTKA is definitely more cost-effective, and rehabilitation and function were the same as in patients who had a staged procedure.
Sciwora lesions are common in children but rare in adults. In adults, they are often associated with spondylosis, and minor trauma may result in paralysis of varying degrees.
In our unit we conducted a retrospective analysis of adult patients with spinal cord injuries. Only two had Sciwora lesions. One lesion was in the thoracic spine and the other in the lumbar spine. The thoracic lesion led to complete paraplegia, with intrinsic cord damage. It was treated conservatively and the patient did not recover. The lumbar lesion was incomplete, with traumatic disc prolapse that recovered after discectomy.
Management of Sciwora lesions of the thoracic and lumbar spine depends on MRI findings.
We evaluated the effectiveness of arthroscopic repair in patients with shoulder instability owing to a bony fragment as part of the Bankart lesion, using spiked Suretacs, sutures and anchors.
Over a two-year period, we followed up 23 of 25 consecutive cases, all with a bony fragment as part of the Bankart lesion. The mean age of patients, all of whom were male, was 21 years (17 to 35). Almost all injuries were sustained playing sports. Patients were clinically evaluated at six weeks and 20 weeks postoperatively and interviewed telephonically.
Full arthroscopic examination was performed in a lateral decubitus position. The affected capsular structures and labrum, with its attached bony fragment, were fully mobilised. The bony fragment was always attached to the capsular structures, with labral ring intact. We used a spiked Suretac anchor to reattach the bony fragment to its original anatomical position, and Mitek anchors and no. 1 Ticron sutures for individual reattachment of the capsule and ligaments. Postoperatively patients were immobilised in a shoulder sling for six weeks. Early restricted active and passive movements were advised. Patients routinely received postoperative physical and biokinetic rehabilitation. The mean follow up period was 16 months (5 to 29). There was no redislocation or subjective instability.
This technique yields excellent results, but because it is technically difficult should be used only by experienced shoulder arthroscopists with thorough knowledge of pathological shoulder anatomy.
A nine-year-old girl presented with a four-year history of progressive bowing of the left tibia. She had been seen in our clinic three and four years earlier, when no treatment was advised. She had been complaining of mild pain in the left leg for one month but was otherwise not very perturbed about her deformed leg.
Examination showed bowing of the left tibia, no leg length discrepancy, no limp, and a normal left knee and ankle. Radiological examination showed features of osteo-fibrous dysplasia of the left tibia, with eccentric expansion of the cortex, intracortical osteolysis, marginal sclerosis encroaching on the medulla and diffuse lesional calcification. No other bones were involved.
Because of the progressive bowing of the tibia and the mild pain, the recommended loose observation of the patient was abandoned. Daily treatment with 30 mg IVI pamidronate for three days resolved the pain. One month after the latest presentation the lesion was biopsied. Histological examination confirmed the diagnosis of osteofibrous dysplasia of the tibia. There was no evidence of adamantinoma.
The literature on this rare bone lesion in childhood supports the use of open biopsy if the deformity becomes painful, the bowing is progressive and the patient presents after the age of nine years. Important differential diagnoses include fibrous dysplasia and adamantinoma.
The treatment of large bony defects following osteomyelitis and trauma with skin damage is challenging. This paper reports the results of fibular transplant for tibial defects.
Between 1990 and 2000, five children aged four to nine years were treated. Four had pyogenic osteomyelitis and one a compound fracture with bone loss. All had large wounds on the medial aspect of the tibia. Before reconstruction, conservative treatment lasted five to six months. Sequestrectomy and debridement were performed before fibular transfer.
At surgery the fibula was divided below the physis and transferred to the remaining tibia, deep to the tibialis anterior muscle belly. In two cases the fibula was fixed to the lateral aspect of the tibia with screws, and in three into the metaphysis with K-wires. Bone graft was packed around the transfer. Immobilised in a cast for four to six months, the leg was later protected with a calliper.
Follow-up ranged from 9 months to 10 years. All children are ambulant, four with callipers and one independently. The latter shows evidence of tibialisation of the fibula. Follow-up continues and the remaining four transfers show solid union and signs of fibular hypertrophy.
Osteomyelitis remains a crippling condition that results in bone defects. Fibular transfer is a salvage procedure and an alternative to ablation in cases of severe bone loss with infection and scarring. It should be reserved for difficult cases with extensive defects where conventional bone grafting is not possible.
At the same time as the LCS knee, the ARD knee was developed. We aimed to assess whether over a 10 to 15-year period the SS 86 rotational platform knee system stood the test of time.
In a retrospective study, we followed up 250 patient, assessing patient satisfaction, range of motion and radiological appearance. Patient satisfaction was high and range of motion and radiological appearances very good.
We discuss aspects of glenohumeral instability and rotator cuff tears in a clinically orientated approach, presenting a new way of quantifying structural bone loss from the anterior glenoid and defining the Glenoid Index as an indicator of the appropriate surgical approach to address anterior instability.
Repair of the rotator cuff depends on viable and functional muscular tissue. We discuss the potential for repair of the supraspinatus tendon in relation to the tangent sign, fat infiltration and retraction. Comparing MRI and arthroscopic findings, we highlight pitfalls in the diagnosis and repair of the subscapularis tendon.
Between January 1990 and October 2000, 108 total hip arthroplasties using a cemented polished titanium stem and a cemented ultra-high molecular weight polyethylene (UHMWP) cup were performed at our hospital. Because during routine follow-up visits we noted instances of resorption of the calcar, we decided to assess whether this was a problem. We were able to assess 85 of the original 108 hips.
Calcar resorption was observed in 43 hips. The extent of calcar resorption varied from 1 mm to over 15 mm. In one patient a biopsy showed typical polyethylene granuloma.
Because there is a risk of long-term failure, we concluded that it is inadvisable to use a cemented polished titanium stem when UHMWP is one of the bearing surfaces.
Painful conditions of the acromioclavicular (AC) joint are common in South Africa, particularly among sportsmen. These conditions are often treated by open excision of the distal end of the clavicle, but an arthroscopic procedure offers many advantages.
From February 1994 to February 2000, we performed 138 procedures. The mean age of patients ({71% men and 29% women) was 29 years (19 to 53). In cases of rotator cuff impingement, arthroscopic acromioplasty was followed by clavicular excision via the subacromial route. With a normal acromion and rotator cuff the AC joint was approached through two superior AC portals, avoiding removal of the AC ligaments. In all cases a standard 3.5-mm arthroscope was placed in one portal for viewing and the mechanical shaver inserted through the other. About 7 mm to 8mm of bone was removed from the clavicle. Patients were in hospital for about a day and 87% were discharged the same day.
The mean follow-up time was 34 months (2 months to 4 years). Patient satisfaction was high in 32%, fair in 60% and poor in 8%. Most patients (92%) returned to all previous sports and activities.
We concluded that the arthroscopic Mumford procedure is at least as successful as its open equivalent. It can be done as an outpatient procedure and permits a rapid return to activities. Cosmesis is excellent and stability of the AC joint is preserved.
The rotator cuff is sited on the anatomical neck of the humerus and is formed by the insertion of the supraspinatus (SP), infraspinatus (IS), teres minor (TM) and subscapularis. All play a vital role in the movement of the glenohumeral joint, and the anatomy is of critical importance in arthroscopic rotator cuff repair. We undertook an osteological and gross anatomical dissection study of the insertion mechanism of these tendons, in particular the SP .
The SP inserts by a triple or quadruple mechanism. The ‘heel’ (medial) and capsule fuse, inserting into the anatomical neck proximal to the anterior facet of the greater humeral tubercle. The ‘foot arch’ inserts as a strong, flat, fibrous tendon into the facet. This area is cuboidal, rectangular, or ellipsoid, and measures 36 mm2 to 64 mm2. In about 5%, the insertion is fleshy (pitted), rendering it weaker than a tendinous attachment. The ‘toe’ lips over the edge of the facet laterally and fuses with the periosteum, fibres of the inter-transverse ligament and the IS. A proximal ‘hood’ of about 4 mm stretches down inferiorly and fuses with the periosteum of the humeral shaft. The subacromial or subdeltoid synovial bursa are sited laterally.
The IS and TM insert into the middle and posterior facets (225 mm and 36 mm2) at respective angles of 80° and 115°. The inferior portion of the TM facet is not fused with the shoulder capsule. The subscapularis inserts broadly into the lesser tubercle, and the superior fibres fuse with the shoulder capsule and intertransverse ligament. The insertion of the subscapularis does not contribute directly to the formation of the ‘hood’, which belongs exclusively to the SP, IP and TM.
This study confirms the complexity of the SP insertion and suggests that an unfavourable attachment or biomechanical anatomical malalignment may lead to eventual tendon/cuff degeneration.
Calcium sulphate is now a proven adjunct to the replenishment of bone stock in joint replacement surgery. Alone and as a composite, it has been used successfully for many years in both dental and orthopaedic applications. OsteoSet (Wright Medical Technology), a processed, purified material, has been used as a bone void filler in 51 revision total hip arthroplasty (THA) procedures.
Follow-up of these cases ranges from 3 to 48 months. Radiographs show that the calcium sulphate has disappeared in all cases. In all but three patients, all of whom had failure of the acetabular component or infection, the calcium sulphate has been replaced with what appears to be trabeculated cancellous bone. Clinical results for cases that did not have mechanical failure or infection are indistinguishable from any revision THA in which the acetabular component is well fixed.
Implantation of the calcium sulphate pellets calls for preparation of a well vascularised bed. The pellets are placed in such a way that load is not transferred to them from the implanted acetabular component. Rather, the load should be transferred from the acetabular component directly to host bone. Postoperatively, load bearing is limited for at least eight weeks and for longer of the quality of the supporting bone is poor.
Periprosthetic fractures may occur intraoperatively or postoperatively. The incidence of is approximately 0.6% in primary and 2.4% in revision total hip arthroplasty. Predisposing factors include stress risers, osteolysis, osteopoenia, singly or in combination. Focusing on postoperative fractures, this paper provides a management algorithm.
If the fracture is stable, conservative treatment is appropriate. If the fracture is not stable, one needs to determine whether the prosthesis is loose or not. If the prosthesis is loose, further management will depend on the quality of the bone stock. Good bone stock will allow revision with a long stem or impaction grafting, while poor bone stock will require extensive allografting. Similarly, the adequacy of the bone stock determines the management regime if the pros-thesis is not loose. In the presence of good bone stock, it is usually possible to carry out open reduction and internal fixation. Poor bone stock requires bicortical onlay allografting.
From 1994 to 1998 36 periprosthetic fractures, 14 with stable implants and 22 with unstable, were treated. The stable implants were treated with Dall Miles plates, fixed with cables and crimp-sleeves, bicortical screws distal to the fracture and unicortical screws proximally. The fracture united in 11 hips, two of which subsequently required prosthetic revision for femoral loosening. In one hip the fixation failed with fracture of the cables. Despite other adverse reports, this type of system is recommended for fixation of periprosthetic fractures where the prosthesis is stable.
The 22 periprosthetic fractures with unstable implants were treated using the Bicontact long stem revision implant. Two distal interlocking screws provided early rotational and axial stability, and 14 patients had additional allografting.
Radiological evidence of fracture healing was apparent in all cases. One prosthesis subsided by more than 5 mm with fracture of the interlocking screws. Cementless long stem revision is the treatment of choice for periprosthetic fractures associated with a loose implant.
To ensure successful outcome it is necessary to determine the extent of the fracture, to assess fracture stability and to appreciate the available and appropriate treatment options. It is necessary to ‘be prepared’: these are challenging problems and the final decision often hinges on intraoperative findings.
Supracondylar femoral fractures challenge even the most experienced trauma surgeon. Fracture comminution often extends into the articular surface, increasing the risk of joint stiffness and post-traumatic arthritis. This is a preliminary prospective report of 42 supracondylar femoral nailing procedures performed on 41 patients between July 2000 and March 2001.
The mean age of the 21 women and 20 men was 62 years. Five fractures were compound. Classified according to AO classification, there were 28 type-AIII fractures, 10 type-AII, two type-CIII and two type-CII. In all cases a percutaneous surgical technique was used and a 13-mm x 250-mm supracondylar nail inserted. The mean operative time was 70 minutes. Mean follow-up was four months (2 to 10). There were no deep or superficial infections and no implant failures. Twenty fractures healed with no shortening within four months. The mean flexion arc was 105° (5° to 130°). Eight patients with osteoporosis had 1 cm to 2 cm of shortening, which did not affect functional outcome. Of the 20 patients whose fractures united, 17 had no pain and three had mild anterior knee pain. A single patient had 8° of valgus angulation at the fracture site.
This study shows that supracondylar femoral nailing provides improved fracture stabilisation both in elderly patients with osteoporotic metaphyseal bone and in younger patients with extensively comminuted fractures. Percutaneous techniques eliminate the need for extensive surgical dissection, shorten operation times and reduce blood loss.
There is great confusion in the literature on mechano-transduction in osteoblasts. This is partly due to the use of hyper and hypophysiological systems for applying forces to cells. We only find evidence for the role of ion channels at hyper-physiological levels of strain. The cells are far more sensitive to tension than compression indicating that structures within the cell are decisive in determining response and that there is no tensegrity within the cell. Single cell mechanical measurements using an adapted atomic force microscope built in our lab, also does not show any evidence for a tensegrity structure. Analysis of the dimension of stretch and the amount of force needed to activate cells indicates that stretch activated ion channels are not involved as the force required is extremely high in relation to the activation energy of an ion channel. The force required to activate at the mechanosensing system is more in line with the forces generated inside a cell by the actin-myosin structure of several hundred thousand piconewtons.
We find no evidence for any other pathway than a PLC-PKC-Calcium pathway involved in any of the signal transduction pathways, but other pathways are involved in hyperphysiological stretch. One of these induces ICAM-1 and thus can induce inflammatory pathways through cell-cell binding of macrophages and other cells.
Due to the very high energies involved in activating the mechano-transduction pathways we do not see any graviception mechanism of single cells. Indeed many microgravitx flights of 25 seconds duration and a flight of 6 minutes did not show any effect in intracellular calcium. The cellular response to microgravity, if it is not an artefact, is not related to mechanosensing.
This work was supported by the German Space Agency (DLR)
In the past, many high tibial osteotomies were done to relieve symptoms of osteoarthritis. These osteotomies have largely been replaced by total knee arthroplasty (TKA).
This paper presents the long-term results of 270 osteotomies followed up for 10 years and discusses the complications involved in subsequent conversion to TKA.
Using the trabecular bone bioreactor (ZETOS) developed in our laboratories we have investigated the formation of bone using the fluorescent bone seeking markers calcein and alizarin red. And the association of bone formation with the increase in stiffness with mechanical loading.
10 mm diameter bone cores 5 mm thick were obtained from the distal radius /ulna of cows obtained at the slaughter house. by precision cutting with diamond saws and keyhole cutters (our pattern) in sterile 7–10°C phosphate buffered saline (PBS) and cultured in a variation of DMEM containing fructose HI GEM.
We gratefully acknowledge support by the German Arthrose Foundation (DAH) and the AO in Davos, CH. DJ is a recipient of a Fork award from the AO
Because there are a number of complicating factors, total hip arthroplasty (THA) performed following acetabular fractures has a less favourable prognosis than when done for primary degenerative arthritis. Patients who have had ace-tabular fracture and present for consideration of THA need careful clinical and radiological assessment. Investigation should include AP and lateral radiographs, 45° inlet/outlet views, obturator and iliac obliques, Judet views and CT scan, with or without 3D reconstruction. There are various classifications defining whether the bone deficiency is contained or uncontained and the extent of the structural defect. Treatment options include autograft, allograft together with mesh, screws, plates, rings, cages, etc.
It is probably preferable to undertake THA sooner (as soon as there is radiological evidence of incongruent articular surfaces) rather than later, as this reduces the delay between fracture and recovery from THA, and any inadequate reduction can be minimised or corrected. The surgical approach must allow adequate access for the intended reconstruction. Small contained or uncontained defects can be treated with cemented or cementless implants and limited grafting. Large defects require structural reinforcement, bone grafting, a retaining cage and, unless a custom-made implant is used, cemented fixation.
Potential problems at the time of surgery include sciatic nerve injury (beware the ‘double crush syndrome’) obstructive hardware, heterotopic ossification, avascular necrosis of the acetabulum and occult infection. Patients who are elderly or who present with markedly impacted fracture, extensive abrasion or fracture of the femoral head, displaced femoral neck fracture, and extensive acetabular comminution in the presence of osteopoenic bone, may warrant acute management with THA.
Early experience of THA in the treatment of selected acute fractures is encouraging. However, the clinical results of THA after fractures of the acetabulum are often disappointing, and there is no current evidence that open reduction and internal fixation improves the success of the subsequent THA.
THA following acetabular fractures is a challenging procedure with a high complication rate. Appropriate investigation and preoperative planning reduces the risk of complications.
Little work has been done on gait initiation in children and there is no published data on gait initiation with cerebral palsy. The aim of this study was to examine the ground reaction forces and centre of pressure in normal children during gait initiation, to compare these to similar values in hemiplegic children and to try to identify differences between the two which may be diagnostic for hemiplegia.
Patients and methods: Five normal and five hemiplegic children were studied. Kinematic and dynamic data were collected using a CodaTM motion analysis system and KestlerTM force plate. All subjects stood with one foot on and one foot off the force plate and walked off upon hearing an audible cue. Tests were repeated measuring right and left, normal and hemiplegic legs as both stance and swing legs. Ground reaction forces in the X,Y and Z axes, centre of pressure and kinematic data were collected and studied.
Medio-laterally the stance GRF tending to adduct falls initially and subsequently rises with a bimodal peak. The forces in the swing leg reciprocate these forces.
2) Hemiplegic children. The overall pattern seen when the normal leg is the stance leg are similar to those in normal children with certain specific variations in force development and magnitude. When the hemiplegic leg is the stance leg the overall patterns are again similar but considerably less smooth with characteristic changes indicative of neuro-muscular disturbance. The initial “adjusting” forces tend to be larger indicating the greater force required for control.
Discussion: The pattern and relative magnitude of forces measured for normal children are identical to those previously reported for adults. This validates our study design and indicates that central programming for gait initiation develops early in life. It is therefore an early developmental skill and may be used as a diagnostic test in childhood. Significant variations are seen in cerebral palsy. Knowledge of these specific changes may allow earlier and more accurate diagnosis of cerebral palsy in children under investigation for movement disorders. Normal GRF patterns during gait initiations may provide early reassurance for parents of children suspected of having cerebral palsy.
The Exeter totally collarless, double-tapered femoral component was developed in 1969 jointly at the School of Engineering at the University of Exeter and the old Princess Elizabeth Orthopaedic Hospital. At the time, in common with a number of implants in contemporary use, the new Exeter stem was manufactured from the rather ductile stainless steel EN58J. The original version of the Exeter stem had a polished surface. This feature was not part of the original design specification, but was demanded by the current British standard governing the use of EN58J in orthopaedic implants. At that time, no thought was given to the possibility that the surface finish of the stem might influence outcome.
Used from 1970 to 1975, the original stems rarely came to need replacement because of loosening. The major complication was the incidence of stem fracture, first seen in 1973, which has reached 4% over a 25 to 30 year follow-up. A stronger stem was introduced at the beginning of 1976. This was manufactured from 316L. As there was no standard demanding a polished surface, this stem was manufactured with a surface two orders of magnitude rougher than the surface of the original polished Exeter stems. While the introduction of this stem almost completely solved the problem of stem fracture, with it appeared notable problems of femoral endosteal bone lysis and aseptic stem loosening, hardly seen with the original polished stems. The study of retrieved prostheses showed the matt surface stem to be prone to abrasive wear against the inside of the cement mantle, and that this phenomenon could lead both directly and indirectly to stem loosening.
Unfortunately, a decade passed before the polished stem was re-introduced in 1986. A monobloc version was used until the beginning of 1988, when the modular Exeter Universal stem was introduced. With both the monobloc and modular versions of the polished Exeter stem, both aseptic loosening and localised endosteal bone lysis have become rare.
Further retrieval studies have shown that in polished and matt Exeter stems the wear processes between stem and cement are fundamentally different. This difference may explain the substantial clinical difference in outcome between these two types of stem. These considerations lead to the view that abrasive stem wear in matt stems is probably a major cause of failure, and more important than failure of cement.
Because there is little in the literature about specific presentation and examination methods for acromioclavicular (AC) joint pathology, we aimed to define and identify the most reliable tests.
We identified and examined 30 patients with probable AC joint pathology. We then excluded eight patients who experienced no pain relief after local Lignocaine infiltration, and examined 22 patients, two of whom had bilateral shoulder problems.
There were 15 complaints of AC joint pain, 13 of anterior pain, five of posterior pain and five of lateral pain. Pain radiated anteriorly in 14 patients, posteriorly in two, laterally in three and to the cervical region in three. Pain increased with weight-bearing in 18 shoulders, on elevation in five, on activities of daily living in six, at night or on being lain on in 11, and on reaching across the body in three. Clinical examination revealed swelling in seven shoulders and AC joint prominence in seven. There was local tenderness in 21 shoulders and there were crepitations in four. The forced cross-body test produced pain in 22 shoulders. In 22 shoulders, elevation was less than 60°. Jobe’s test was positive in 20, the Speed’s test in 19, O’Brien’s test in 15, the compression test in 15, the distraction test in 13. A painful arc was present to 160° in 13 shoulders. There was neck tenderness in 13 patients. Associated conditions included two cases of shoulder arthritis, six of impingement, two rotator cuff tears, two cases of biceps tendinitis and two of cervical pathology. Radiological changes were evident in 19 AC joints, 13 shoulder joints and 11 cervical spines. On ultrasonography, pathology was resent in 10 of 15 cases.
The most common symptoms were pain with weight-bearing, elevation and lying on shoulder. Anterior and posterior pain was the most common. The most common clinical findings were local tenderness, pain on elevation and the forced cross-body test, positive Jobe’s and Speed’s tests. Because no test is 100% accurate, the whole clinical presentation must be taken into account. Local infiltration of the AC joint is extremely helpful.
The weight of the Ta increased for both cardiotoxin doses. There was an increase in the size of the fibres with or without SC transfer.
We reviewed the outcome of prosthesis-to-bone fixation of the rough titanium femoral stem of an Ultraloc prosthesis (Zimmer, USA).
Between 1989 and 1991, 41 of 55 patients were traced for long-term review at a mean of 107 months (55 to 139). The primary pathology was avascular necrosis in 18 patients, osteoarthritis in 16, ankylosing spondylitis in two and Perthes’ disease in one, and there were two cases each of trauma and dysplasia. There was an equal number of men and women, whose mean age at operation was 47 years (24 to 66).
Radiological assessment of the stems revealed well-fixed stems in 40 patients (97.6%). In 20 stems small granulomata due to polyethylene wear were found in Gruen zones 1 and 7, and in one stem in zones 1, 6 and 7. Only one stem required revision for loosening (done at 59 months), but cups (48.8%) were loose. Three patients required revision owing to polyethylene wear and one for sepsis. In all four cases, removal of the stem was extremely difficult. The remaining 16 hips await revision.
Although the results obtained using an Ultraloc prosthesis are poor, from the point of view of fixation the stem has functioned successfully. However, the formation of granulomata causes cup loosening.
In total hip arthroplasty (THA), it is preferable that patients have an ideal preoperative Body Mass Index (within 20% of the normal). The purpose of this study is to determine whether patients maintain their preoperative reduced weight after THA and whether the effort of encouragement and cost of a dietician to lose weight preoperatively is worthwhile.
Conducted over five years, this study included 100 patients with a mean age of 62.5 years (34 to 83). Preoperative and postoperative weights were obtained from clinical records.
There was a postoperative weight increase in 51% of patients and a decrease in postoperative weight in 46%. Pre-operative weight was maintained in 3%.
Mature human intervertebral disc cells have generally been described as being either fibroblast-like or chondrocyte-like; i.e. appearing either elongated and bipolar or rounded/oval. Fibroblast-like cells are observed within the outer regions of the anulus fibrosus whilst chondrocyte-like cells are found in the more central regions of the disc. However, a few reports have noted that in some circumstances disc cells appear to extend more elaborate cytoplasmic processes into their surrounding extracellular matrix. In this study, we have examined healthy and pathological human intervertebral discs for the presence of the cytoskeletal elements, F-actin and vimentin.
Tissues examined included discs of no known pathology, discs with spondylolithesis, scoliosis specimens taken from the convex and concave sides, and degenerated discs. F-actin was not readily observed within discs cells but was a marked feature of vascular tissue within the disc and occasionally seen in infiltrating cells. Vimentin was more readily seen within cells of the inner anulus fibrosus and nucleus pulposus. In general, disc cell morphology was fibrocyte or chondrocyte-like; however, in spondylolisthetic discs, cells with numerous cytoplasmic projections were frequently observed.
The differential morphologies and cytoskeletal composition observed in disc cells may be indicative of variations in mechanical strains and/or pathologies, or indeed of cell function.
The ‘Pi’ plate is an anatomical titanium plate recently introduced for the internal fixation of comminuted intra-articular distal radius fractures. We report our experience with this implant in a prospective series of twelve patients with an average age of thirty six years (range, 26–52 years).
A dorsal approach with release of the EPL tendon and extra-compartmental exposure of the radius between the second and fourth extensor compartments was employed in all cases. Iliac bone graft and a styloid K-wire were used to augment the plate fixation. Post-operatively, active mobilisation was started after wound healing. Wrist motion and grip strength measurements were made at six weeks, three months and six months by the therapist. At six months, patients recovered an average of 85% of range of movement compared with the opposite wrist, except for palmar flexion (65%). No loss of reduction was observed on follow-up radiographs. Complications were compartment syndrome, intraoperative EPL rupture and two cases of extensor tendonitis requiring implant removal.
The ‘Pi’ plate affords rigid fixation of distal radius fractures permitting early rehabilitation. It is however a demanding technique that is not without complications.
Traditional biomedical/ergonomic occupational interventions to reduce work loss show limited success. Attention is now focussing on tackling the psychosocial factors that influence occupational back pain.
A workforce survey of Glaxo Smith Kline (reported to the Society last year) established that clinical and occupational psychosocial factors (yellow & blue flags) act independently and may represent obstacles to recovery. Consequently, a nurse-led intervention was devised. Occupational nurses at two manufacturing sites were trained to identify both clinical and occupational psychosocial factors, and address them using a basic ‘counselling’ technique that reinforces evidence-based messages and advice, along with availability of modified work. The program should ideally be implemented within the first days of absence, with ‘case-management’ by the nurse for a further 4 weeks. Control sites simply offer ‘usual management’. Outcomes at 12-month follow-up are rates for work loss/work retention.
The target for contacting the worker (3 days) was achieved at one site, but not the other (mean 12 days), thus exerting a differential delay in delivering the intervention. The lack of early identification at the second site was due to local reporting/recording mechanisms. This study reveals a third class of obstacles to recovery – black flags – company policies/procedures that can impede occupational rehabilitation programs.
We retrospectively reviewed 52 children treated for tuberculosis of the knee in the 21-year period 1979 to 1999.
The mean age at which the condition was diagnosed was 5.3 years (8 months to 13 years). The median duration of symptoms was four weeks (1 month to 3 years). All patients presented with swelling, mainly owing to synovitis. Pain was a symptom in only two thirds of patients.
Using Kerri and Martini’s classification of radiological appearances, 33 knees were stage I (osteopoenia), 15 stage II (osteopoenia with erosions), two stage III (joint space narrowing) and two stage IV (joint space narrowing with anatomical disorganisation). All knees had either positive histology (caseating granuloma) and/or a positive culture for tuberculosis.
Treatment was with rifampicin, isoniazide and pyrazinamide for nine months. No synovectomy was done. Of the 48 knees with stage-I and stage-II disease, 22 were immobilised for at least three months and 26 actively mobilised.
At a mean follow-up of five years (2 to 16 years), the results were classified according to Wilkinson. All stage-I and stage-II knees had an excellent result (full range of motion) or good result (more than 90° of flexion). Stage-III and stage-IV knees had a fair result (less than 30°of flexion) or poor result (ankylosis). In stage-I and stage-II knees, immobilisation did not affect outcome.
In the same period, 25 knees with a non-specific histology and negative culture presented the problem of the differential diagnosis between tuberculosis and particular juvenile rheumatoid arthritis (JRA). Of these 17 were subsequently diagnosed as JRA. A histological study assessed the value of synovial lining (SLC) hyperplasia. The sensitivity of SLC hyperplasia for JRA was only 53%. Synovial biopsies from 10 joints with tuberculosis (positive histology or culture) were subjected to the polymerase chain reaction test. The sensitivity was only 40% for tuberculosis.
We retrospectively reviewed 10 children treated for tuberculosis of the elbow over a 21-year period from 1979 to 1999.
The mean age at diagnosis was 5.5 years (1 to 11). The median duration of symptoms was 10 weeks (l week to 18 months). The patients presented mainly with swelling of the elbow joint due to synovitis. Radiological appearances of the elbow at presentation were assessed according to Kerri and Martini’s classification. One elbow was stage I (osteopoenia), eight were stage II (osteopoenia and erosions) and one stage III (joint space narrowing).
Open biopsy was performed on all patients. There was positive histology (caseating granuloma) and/or positive culture in eight patients. Of the two patients with non-specific histology and negative culture, one was found on chest radiograph to have tuberculosis involvement and the other healed on anti-tuberculosis therapy. All patients were treated with rifampicin, isoniazide and pyrazinamide for nine months. No synovectomy was done. Postoperatively all patients were immobilised in a backslab and then actively mobilised.
At a mean follow-up of three years (1 to 10), patients were assessed according to a modification of Kerri and Martini’s classification. Seven of the eight stage-I or stage-II patients had an excellent result (full range of movement) or good result (loss of less than 30% of range of movement). One stage-II patient had a fair result (loss of range of movement of 30% to 50%). The stage-III patient had a poor result (loss of more than 50% of range of movement).
We concluded that elbows with stage-I and stage-II disease (synovitis) have a good outcome. Anti-tuberculosis chemotherapy is effective in the treatment of stage-I and stage II disease. Synovectomy is unnecessary.
Intervertebral disc cells exsist in a precarious nutritional environment. Local concentrations depend on both nutritional supply and demand. Little is known about the metabolism of disc cells; existing data focuses on intact tissue, where the local metabolic environment is unknown. We have thus developed a closed chamber to study the metabolism of isolated cells under controlled conditions.
Bovine disc cells were isolated from coccygeal discs and transferred to the sealed chamber, in which embedded electrodes measured pH, pO2 and glucose concentration, and a port allowed sampling and addition of metabolic reagents. Metabolic rates were assessed from concentration changes. Cell viability was assessed and intracellular ATP measured at completion of each experiment.
Under standard conditions, metabolic rates were similar to those measured in tissue, with a glucose:lactic acid ratio of approximately one to two. We have also examined the effect of extracellular pH on nucleus pulposus cell metabolism. Between pH 7.4–6.8, metabolism is insensitive to extracellular pH, and lactic acid production agrees with the literature
These results show a fall in lactic acid production with extracellular acidification, which in vivo arises mainly from lactic acid produced by the cells. This may be protective. However the decrease in metabolism, and hence loss of ATP, may have a detrimental effect on the cells. There is thus a complex interplay between different components of the nutritional environment. Investigating these in combination should give valuable information about disc cell metabolism, as changes in cells metabolism can affect nutrient availability and hence cellular activity and viability.
Horse riding is a common pursuit and is more dangerous than believed. Most injuries of the hand and wrist are caused by falls, as in other sports. However, exclusive to riding are injuries sustained whilst leading a horse. Avulsion injuries are well recognised but little has been reported on phalangeal fractures in this situation.
We report on seven cases that required hospitalisation in our hand unit, for injuries from horses over a two year period. Six of these patients sustained multi-fragmented spiral periarticular fractures involving the middle and proximal phalanx and one a horse bit.
We will discuss in detail the mechanism of their injuries, the surgery undertaken, their post-operative rehabilitation and overall outcome. Furthermore we review the recommended horse handling technique and contrast it with the mechanism of injury in our cases.
In our experience the fractures seen were unstable, comminuted and needed internal fixation. One patient developed a delayed union and three post-operative stiffness. Our results suggest that fractures whilst leading horses are more complex than recognised, usually need surgery and often have a relatively poor outcome. All of these cases were largely preventable and could be attributed to incorrect horse leading technique.
This study compared the effect of manipulation with a period of normal activity on the range of intervertebral sidebending.
Thirty asymptomatic male volunteers were randomised to treatment or control groups. All were subjected to low-dose X-ray screening through 80° of passive lumbar spine side-bending. Motion sequences were digitised at a 5Hz sampling rate. The treatment group (n=16) had rotary manipulation to each lumbar linkage, followed by normal activity. The control group (n=14) had normal activity only. Both groups were then re-screened. Each vertebral pair was tracked and intervertebral rotation throughout the motion measured. Three subjects were analysed 10 times for reliability and all intervertebral motion was tracked twice.
Twenty-one manipulated linkages and 10 controls met the reliability criteria. For non-manipulated segments the mean range at first screening was 14.2° (SD 1.39) and manipulated segments 12.8° (SD 3.81). The range of the non-manipulated segments increased by +0.9o and the manipulated segments by +0.4°.
The change in manipulated segments was negligible and similar to controls, although the instrument can be sufficiently reliable to measure a 2° difference. The technique is sufficiently robust to determine if spinal manipulation changes these ranges in selected patients.
In order to assess the incidence of avascular necrosis (AVN) following septic arthritis of the hip in children, we retrospectively reviewed the outcome of 227 hips with septic arthritis treated over an 18-year period. The mean age at presentation of the 221 patients, six of who had bilateral conditions, was 5.6 years (5 months to 14 years).
All patients underwent open arthrotomy and pus was found at surgery. Patients were treated with cloxacillin and patients aged six months to two years also received ampicillin. Staphylococcus areus was cultured in 51% of hips, Haemophilus influenzae in 9%, Streptococcus pneumoniae in 4% and Streptococcus pyogenes in 6%. The remaining 30% had no growth. Septicaemia was present in 20 patients at presentation.
AVN developed in 24 hips (10.5%), and chondrolysis in five (2.2%). Of the hips with AVN, seven were septicaemic. The most important factor in the development of AVN was a delay of five or more days from onset of symptoms to surgery. The risk of AVN with five days’ delay was 50% and increased exponentially with a longer delay. Septicaemia did not constitute a risk per se, but did contribute to a delay in diagnosis of hip involvement. The total head was involved in 14 of the 24 hips with AVN, while 10 had partial head involvement, with a better long-term outcome.
Nitric oxide (NO) production by the inducible NO synthase (iNOS) and enhanced emigration of leukocytes into synovial tissue are suggested to play a crucial role in mediating chronic joint inflammation such as rheumatoid arthritis. The effects of iNOS inhibition in experimental arthritis are dicussed controversally. The aim of our study was to analyze the synovial microcirculation and leukocyte endothelial cell interactions in iNOS-deficient mice with antigen-induced arthritis (AiA) in vivo. 14 homocygote iNOS-deficient (iNOS KO C57BL6/J x 129SvEv; Merck & Co., Rahway, NJ, USA) and 14 iNOS-positive (C57BL6/J x 129SvEv) mice were used for our study. The patella tendon was resected, which allows for visualization of the intraarticular synovial tissue of the knee joint using intravital fluorescence microscopy. Animals were allocated into four groups (iNOS +/+, iNOS +/+ with AiA, iNOS −/− and iNOS −/− with AiA) (n=7 each group). On day 8 after arthritis induction, functional capillary density (FCD), fraction of rolling leukocytes, and the number of adherent leukocytes were quantitatively analyzed in synovial postcapillary venules. Histologic sections were performed to assess leukocyte infiltration of the synovium.
FCD or leukocyte-endothelial cell interaction were not altered in healthy iNOS-deficient mice in comparison to iNOS +/+ animals. However, in iNOS-deficient animals with AiA there was a significant increase in the fraction of rolling (0,510,05) and in the number of adherent leukocytes (729126 mm-2) in comparison to wild type mice with AiA (0,330,07 and 565110 mm-2) (MWSEM, p < 0,05). Histologic sections revealed increased leukocyte infiltration in iNOS-deficient animals with AiA compared to iNOS +/+ arthritic animals.
In our study, there was an enhanced leukocyte accumulation and extravasation in iNOS-deficient mice with antigen-induced arthritis in comparison to iNOS-positive animals with arthritis. Thus, the induction of iNOS appears as critical protective response to AiA possibly by reducing leukocyte adhesion and infiltration.
Edema and infection represent serious complications of blunt extremity trauma. It is important to differentiate between pathophysiological changes within tissues proximal and within distal to the site of trauma. The aim was to investigate the effects of soft tissue trauma on the microcirculation of the mouse lower limb. Endothelial leakage and leukocyte accumulation proximal and distal to the site of trauma were studied using intravital fluorescence microscopy.
Low-energy trauma to the lower limb was defined in previous experiments as a trauma transferring 50% of the energy required to produce tibial fracture. The trauma was inflicted under general anesthesia by an accelerator, hitting the mid-section of the calf in a perpendicular direction. 5, 90, and 180 minutes after trauma, the following microcirculatory parameters were measured: diameter of arterioles, venules, functional capillary density (FCD), extravasation of FITC-dextrane, and leukocyte-endothelial cell-interactions. Two groups (control and trauma) were studied proximal to, distal to and at the site of trauma. Skin, subcutaneous tissue and muscle were investigated individually in the trauma and the control groups (each group n=7).
At the site of trauma, distinct extravasation and edema formation in all tissues was observed. In subcutaneous and muscle tissue, microvascular thrombosis as well as edema were detected proximal and distal to the trauma. FCD was reduced in muscle and fat tissue. The numbers of rolling and adherent leukocytes were enhanced 5 minutes after trauma and throughout the observational period.
Our results demonstrate endothelial leakage and extravasation early after low-energy soft tissue trauma in all soft tissues proximal and distal to the site of trauma. In addition, we found high accumulation of leukocytes in all locations, especially in soft tissues. The model presented is ideally suited for the in vivo investigation of new therapeutic strategies for edema and thrombosis prevention in animals with soft tissue trauma.
To assess the role of pelvic osteotomy during the closure of bladder and cloacal exstrophy, we retrospectively reviewed 10 patients treated from 1990 to 1999.
Six patients had cloacal exstrophy and four had bladder exstrophy. Two patients had no primary osteotomy. Two had posterior, two anterior pubic and two midiliac oblique osteotomies. Osteotomies were performed at a median age of 5.3 weeks.
The mean follow-up time was five years (2 to 11). We assessed facilitation of closure, reconstitution of pelvic anatomy, maintenance of interpubic distance (IPD), urinary continence and gait.
All osteotomies facilitated soft tissue closure at the time of surgery. Subjectively, the best restoration of pelvic anatomy was with a midiliac oblique osteotomy. In all patients, IPD increased progressively with increasing age (mean pre-operatively 3.3 cm, postoperatively 1.9 cm and 5.0 cm at follow-up).
The results of soft tissue surgery to provide continence and maintain abdominal wall closure were poor. All procedures to address incontinence failed and there was a 100% dehiscence/sepsis rate. Although half the children had increased external rotation of the hip at review, only one child had an externally rotated joint. .
The current long term results of total joint arthroplasty are limited by mechanical wear of the implants with an associated immune mediated bone lysis with subsequent loosening and eventual failure. It has been demonstrated that the osteolysis seen in cases of aseptic loosening is mediated by the immune system, particularly, both directly and indirectly, by activated macrophages. Macrophages indirectly cause osteolysis through release of the osteoclast activating cytokines: TNFα, IL-1 and PGE2 and also directly resorb bone in small amounts when activated by wear particles.
We wished to determine if macrophage activation and the release of osteolytic cytokines in response to orthopaedic wear debris could be suppressed pharmacologically, with the use of anti-inflammatory and anti oxidant agents.
We utilised established cell culture models of both peripherally derived monocyte/macrophages and lymphocyte enriched co-cultures and examined the effects of polymethylmethacrylate particles alone on the cells in culture. The effects of anti-inflammatory and anti-oxidant agents (dexamethasone, diclofenac and n-acetyl cysteine) in varying concentrations were then examined using ELISA of cytokine release and electron microscopy to examine ultra structural responses.
Cell viability was also measured in cultures over 24 hour periods (at 6, 12 and 24 hours) using Trypan blue exclusion and Coulter counter, while cell type and morphology were determined cytologically, including α-naphthyl acetate esterase cytochemical identification and electron microscopy. The use of N-acetyl cysteine was associated with very significant suppression of TNFα, IL-1β and PGE2 in both macrophage and lymphocyte enriched co-culture with no effect on cell viability. While diclofenac was also associated with significant decreases in cytokine expression it was associated with a decrease in cell viability that approached significance. Dexamethasone did not have a reliable effect on these cytokines. Ultra-structural electron microscopic examination of the cells also demonstrated signs of definite down-regulation of cytoplasmic and nuclear activation.
We have demonstrated, therefore, that novel anti-oxidant therapies and possibly other immune modulating drugs can eliminate the activation of macrophages in response to peri-prosthetic wear particles without any associated decrease in cell viability and thus may provide a means of reducing the incidence of loosening and failure of total joint arthroplasty.
Over a 4 year period 27 children with cerebral palsy underwent proximal femoral derotation osteotomy resulting in a total of 42 operations performed. Each of these children had pre operative gait analysis performed followed by derotation osteotomy. The degree of derotation varied individually and was judged to be correct when the foot lay in a neutral position. Gait analysis was not repeated until 1 year after surgery to allow for complete bony union, recovery of the soft tissues and general patient rehabilitation. Pre-operative and post-operative data were compared to give a quantitative analysis of the actual derotation obtained.
The mean age at the time of operation was 9.7 years (range 4.5–14.5 years). The male : female ration was 6 : 5. the mean amount of femoral derotation achieved was 26.25 degrees (minimum 7 degrees, maximum 66 degrees). The goal of the operation was to correct internal rotation and achieve a hip in a neutral position throughout the majority of the gait cycle. The average hip rotation in a normal able-bodied person is 1.72 degrees of external rotation. 84% achieved more than 75% derotation to neutral. The remainder were considered operational failures.
These results quantitatively demonstrate that proximal femoral derotation osteotomy is a successful operation in cerebral palsy to correct intoeing.
Chondrocyte sensitivity to strain depends on signal transduction pathways which include integrin-dependent increases in intracellular calcium. Human articular chondrocytes were cultured as monolayers in silicone dishes. After loading the cells with the calcium-fluorescent dye Fluo-3/AM the dishes were mounted in a 4-point bending apparatus and then fixed to a laser scanning confocal microscope. Biaxial substrate strain (15 000e) was applied to the silicone dish via a hand operated cam rotated at ~60 RPM (1 Hz) for 10 or for 50 cycles. Changes in intracellular calcium in single cells were determined by measuring the mean pixel values in the basal and stimulated images taken at different time points. The data reported for 50 cycle treatments represent 49 single cells of six independent cell isolations. The data for 10 cycle strain treatment are from a single experimental setup.
Increases in intracellular calcium were consistently observed in chondrocytes exposed to 15 000me for 50 cycles in a range from 1.3- to 4.0-fold with an average of 2.3-fold (SD=0.79). Few cells responded before 30 minutes but most of the responses occurred 30–60 minutes after strain. Consistent intracellular Ca++-increases were also seen after 10 strain cycles, however responses were detected within 5 minutes post-strain. The relative increase (2.7-fold ± 1.7) was similar in magnitude to 50 cycle responses.
Intracellular Ca++-fluxes in chondrocytes and other cells occur by at least two different mechanisms: through stretch-activated channels in the plasma membrane permit immediate Ca++-influx during strain application or by Ca++-efflux from intracellular compartments stimulated by slower acting second messengers. Our results suggest that the early response to 10 strain cycles is due to Ca++-influx via membrane channels while the later response to 50 cycles is due to Ca++-efflux from intracellular compartments, probably mediated by cytokines released in response to an initial Ca++-influx from the medium.
Scoliosis is a disease characterised by vertebral rotation, lateral curvature and changes in sagittal profile. The role of mechanical forces in producing this deformity is not clear. It is thought that abnormal loading deforms the disc, which becomes permanently wedged. Modelling and in vitro studies suggest that such deformations should increase intradiscal pressure. Intradiscal pressure has been measured previously in a variety of clinical environments. The aim of this study is to measure pressure profiles across scoliotic discs to provide further information on the role of mechanical forces in scoliosis.
Pressure readings were obtained in consented patients with ethical approval using a needle-mounted sterilised pressure transducer (Gaeltec, Dunvegan, Isle of Skye) calibrated as described previously. The transducer needle was introduced into the disc of an anaesthetised patient during routine anterior scoliosis surgery and pressure profiles measured. Signals were collected, amplified and analysed using Power-lab and a laptop computer.
Pressure profiles across 10 human scoliotic discs from 3 patients have been measured to date. Pressures varied from 0.1 to 1.2 MPa.
Annular pressures showed high pressure, non-isotropic regions on the concave but not convex side of these discs.
Nuclear pressures recorded from the discs of these scoliotic patients were higher than those recorded previously in non-scoliotic recumbent individuals.
The aim of this study was to compare implementation of RCGP guidelines in patients in Primary Care with acute low back pain between GP and Nurse Practitioner. This report presents preliminary results.
The intention was to recruit 200 patients presenting to GP with new episode of back pain. 50% randomised to NP care, 50% to GP care. Outcome measured by documentation audit and patient feedback. Individuals complete a questionnaire which includes a Low Back Outcome Score (LBOS) at 14 weeks, 6,12 and 24 months. All patients in NP arm given back book and advised against bed rest.
Initial results suggest no significant difference in outcome between GP and Nurse Practitioner patients. Of interest is that 10% and 13% of patients failed to recall important features of management. This implies that audit of healthcare processes by patient questionnaire may be unsatisfactory.
Thromboembolism is a potentially fatal complication of total joint replacement. Some surgeons follow a ‘prophylaxis without compromise’ policy, while others, who realise that there are risks attached to the use of prophylactic drugs, go to the opposite extreme and administer no prophylaxis and no anti-thrombotic drugs, even for pulmonary embolism.
We believe the results of surveillance should determine the administration of anticoagulation therapy. In over 1 500 patients, anticoagulants have been administered only when clinically indicated and after positive Duplex diagnosis. Death due to pulmonary embolism has occurred in only two patients in six years, a reduction from 1.0% to less than 0.05%.
Our treatment protocol divides our patients into high and low risk cases. The results of Doppler and blood tests dictate the method and extent of prophylaxis for high-risk cases, and the therapeutic handling of positive clot formation in the low-risk population.
General Practitioner (GP) attendances for non-specific disease increase after life events. Whiplash injury has the effect of a life event in some people.
The aim of this study was to compare GP attendance rates in the year before and after whiplash injury to establish their rate and cause.
Ninety-eight subjects (62 women and 36 men) with whiplash injuries examined for medicolegal reports, with complete GP records for a year before and after injury.
The number of attendances and the reason for attendance. Consultations after the accident were subdivided into those for neck pain and for other reasons.
Subjects were reviewed more than one year after injury. All described neck pain 11% mild, 62% moderate and 27% severe. GP attendance rates before the accident were within the normal range but increased after (p=0.0001) because of neck pain symptoms. There was no association between attendance rates before and after injury but consultations for neck pain rose in proportion to severity of symptoms (p = 0.0015). Attendances unrelated to neck symptoms fell after injury (p = 0.002).
GP attendances for non-specific disorders increase after life events, but not after whiplash injury as patients focus on their neck symptoms.
The majority of studies investigating the outcome of lumbar decompression surgery have been retrospective in nature and have not used validated measures of outcome. The aim of this study was to prospectively investigate the short and long term outcome of lumbar decompression surgery in terms of function, disability, general health and psychological well being.
Eighty-four patients undergoing lumbar spinal stenosis surgery were recruited into this study. Patients were assessed using validated measures of outcome pre-operatively, and at 6 weeks, 6 months and one year post-operatively.
A significant reduction in pain (p< 0.001) was observed at the 6 week post-operative stage, this did not change at the subsequent assessment stages. Only some of the SF~36 categories were sensitive to change. The sub-categories that were sensitive to change were; physical function (p< 0.05); bodily pain (p< 0.001); and social function (p< 0.05). Improvements were observed in these categories at the 6 week and 6 month reviews. A gradual reduction in the Oswestry Disability Index (ODI) was observed with time, with changes principally being observed between the 6 week and 6 month review, and 6 week and one year review stages (p< 0.05). Minimal changes were observed in the psychological assessments with time. The outcome of surgery could not be predicted reliably from psychological, functional or pain measures.
Lumbar decompression surgery leads to a reduction in pain and some improvements in function.
This study examines patient characteristics, indications for conversion, surgical and anaesthetic technique, peri-operative management and complications of surgery in this small and challenging group of patients. In the six years from 1994 to 1999, 33 conversion arthroplasties were performed for failed femoral hemiarthroplasty. The average age at conversion surgery was 75.5 years (range 65–90). The female to male ratio was 6:1. Primary hemiarthroplasties comprised 24 Austin-Moore, 6 Thompson & 3 Bipolar prostheses. The average interval from primary to conversion surgery was 50 months (6 months to 17 years). The average age at primary surgery was 71.2 years (62–88) – AMP:71.4 years, Thompson’s: 74.2 years, Bipolar: 63.5 years. All hemiarthroplasties were performed for fractured femoral necks. 62% of patients came from the Eastern Health Board area, while 38% were tertiary are referrals from other Health Boards. The average length of stay was 17.5 days (3–24). Indications for conversion included gross loosening/acetabular erosion in 9 cases, suspected infection in 4 cases and abscess/septicaemia in 1 case. All but 3 patients had significant pain (night pain etc.) and/or severely impaired mobility.
We also looked at anaesthetic and analgesic practice, surgical technique and prostheses used.
Post-operatively, mean total blood loss was 1430 ml (420–2280) with an average of 1.4 units of blood transfused (0–5). Intraoperative complications included acetabular & femoral perforation, periprosthetic fracture and cement reactions. Complications post-op (in hospital) included cardiac arrhythmia’s, cerebrovascular accidents, pulmonary embolus, myocardial infarct, respiratory & urinary tract infections, constipation, nausea & vomiting.
The elderly nature of these patients and the physiological stress of what is major surgery allied with multiple co-morbidities make their care especially challenging. A conversion arthroplasty is a procedure with a significant risk of considerable morbidity. Primary total hip replacement or bipolar hemiarthroplasty are options which, therefore, should be seriously considered in the case of fractured femoral necks to minimise the need for further surgery in the future, with all its attendant risks.
The posterior ligament complex (PLC) in the cervical spine comprises the posterior longitudinal ligament, ligamentum flavum and ligamentum nuchae, the latter homologous with the supraspinous and interspinous ligaments at other levels of the spine. In determining instability, evaluation of the PLC is an essential part of the assessment of cervical spine injuries. Disruption of the PLC occurs following flexion injuries, both in compression and in distraction, and following extension injuries with compression. PLC disruption, diagnosed when clinical examination reveals localised posterior spinal tenderness and/or a widened interspinous gap, is confirmed on standard and dynamic flexion-extension radiographs and MRI.
This paper is a retrospective review of 162 patients treated for cervical injuries between 1997 and 2001. There were 83 (51%) distraction flexion, 37 (23%) compression flexion, 18 (11%) compression extension, 17 (10%) vertical compression, six (4%) distraction extension and one (1%) lateral flexion injuries. In 79 patients with pure ligamentous instability, an interspinous stabilisation procedure was performed, using a titanium cable. When associated fractures occurred with PLC disruption, neurologically intact patients were managed conservatively with traction followed by a spinal brace. Patients with a neurological deficit underwent surgery. Using delayed dynamic flexion-extension views and MRI, PLC disruption was diagnosed late in nine flexion distraction injuries without facet dislocation. At follow-up, flexion-extension views showed that all PLC disruptions with associated fractures had stabilised. There were two broken cables in patients who underwent surgery.
Patients with cervical instability following trauma may be treated non-operatively when there are associated fractures, while patients with pure ligamentous instability should undergo fusion. Further, to exclude occult PLC disruption, all cervical injuries should be reviewed on flexion-extension views once the paraspinal muscle spasm has settled.
Thoracic spine fractures and fracture dislocations often lead to neurological deficit, and associated injuries to morbidity and mortality.
An audit conducted between January 1999 and December 2000 evaluated the outcome of 63 patients with fractures and fracture dislocations of the thoracic spine. The mean age of patients, 41 of whom were male, was 30 years. In 45 patients the injury was sustained in a motor vehicle accident, and 23 patients had associated injuries. We used the Margel radiological classification. There were 37 fracture dislocations and 23 pure fractures. Twenty patients had a type-A injury (flexion), of which 19 were type AIII (burst). There were 40 patients with a type-B injury, 35 of which were type BI (flexion distraction), and three type BIII (flexion and axial loading). In three patients there was a type-C injury (rotational). There was total neurological deficit in 39 patients, 10 with type-A, 26 with type-B and three with type-C injuries. Fifteen patients had partial neurological deficit and nine were neurologically intact.
Posterior spinal fusion and bone graft was performed on 43 patients, anterior decompression and bone graft without instrumentation on seven, and combined anterior and posterior surgery on one. The remaining 12 were treated conservatively with orthoses. The neurological status of eight patients improved by a single grade following surgery and the neurological status of two following conservative treatment. Of the 54 patients with neurological deficit, 52 were wheelchair-bound. The poor neurological outcome was comparable to that in other studies.
The intermetatarsal angle is widely used to determine whether a basal or distal metatarsal osteotomy should be used to correct a hallux valgus deformity. We have noticed that the point of intersection of the long axes of the first and second metatarsals on standard pre-operative weight-bearing AP radiographs consistently predicts the type of osteotomy required.
A basal osteotomy is generally recommended if the inter-metatarsal angle is ≥14°, whereas a distal osteotomy is usually sufficient if the angle is less than 14°.
Sixty standardised pre-operative AP weight bearing in-patients undergoing hallux valgus correction were included in our study. The intermetatarsal angle was measured in a standard fashion. The point of intersection in the foot was recorded in terms of the distance from the talonavicular joint.
Using a Pearson’s Correlation coefficient, our study revealed that an intermetatarsal angle of 14° or more consistently intersected either within the talar head or distal to thetalonavicular joint. We propose that this as an accurate and simple method of pre-operatively determining the choice of metatarsal osteotomy.
Dislocations of the thoracolumbar spine, which account for 11% of injuries in the T10 to L2 region, follow a high-energy, flexion-distraction force. In this region, there is a transition from a fixed kyphosis to a mobile lordosis, an absence of costotransverse ligaments and a change of facet alignment from a coronal to a sagittal plane.
In 1999, we treated 12 male and nine female patients with dislocations of the thoracolumbar spine. Their mean age was 30 years. Sixteen patients had been involved in motor vehicle collisions, four had fallen from a height and one had been assaulted with an iron bar. There were 14 Frankel grade-A injuries, one Frankel grade-C, two Frankel grade-D and four Frankel grade-E injuries. The site of injury was T12/L1 in 14 patients, L1/L2 in four, T11/T12 level in four and T10/T11 in one. Associated injuries included electrical burns and a fractured femur. None of the patients sustained visceral injuries. All patients were stabilised with transpedicular fixation. No disc sequestration was found.
Following surgery, one of the 14 Frankel grade-A patients improved to Frankel grade C but 13 made no neurological recovery. The four patients graded Frankel E did not deteriorate. The remaining three patients with partial neurological deficit made a complete recovery. Postoperative sepsis resolved in one patient following debridement and antibiotic therapy.
The thoracolumbar junction is anatomically and biomechanically predisposed to traumatic dislocation. The poor neurological outcome with dislocations at T11/T12 and T12/L1 may be attributed to cord injury, but injuries distal to this level have a better prognosis owing to cauda equina involvement.
There is a desire to reduce the economic burden of low back pain. This in is part because of the 226% increase in invalidity benefits paid out for spinal disorders in the ten years to 1994/5. This paper examines the effect of the change from Invalidity Benefit to Incapacity Benefit in 1995, and considers the utility of these figures as a means of assessing changing patterns of back pain disability.
Data were obtained from the DSS on how benefit data were collected and numbers of days of Invalidity/Incapacity Benefits that were paid from 1983/4 to 1998/9. The data suggest that since 1995 that the rate of spinal disability has fallen and has now been stable at 90 million days per year for four years. The headline Incapacity Benefit figures have a very loose relationship with health impact of low back pain. Around 30,000 people per year make the transition to claiming long term Incapacity Benefit from claiming short term Incapacity Benefit.
Incapacity Benefit figures are of little utility in assessing changes in low back pain disability. Numbers making the transition to Long Term Incapacity Benefit may be a more useful indicator.
Evaluating the effectiveness of conservative treatment of odontoid fractures, from 1997 to 1999 we reviewed 22 cases.
All were treated first in halo traction and subsequently by halo thoracic brace immobilisation. We used Anderson and D’Alonzo’s classification of types I to III. The mean follow-up time was seven months. Initial displacement was measured radiologically and union was evaluated.
In type-II fractures, the incidence of pseudarthrosis was 40%. Fractures with more than 5 mm of initial displacement and more than 10° angulation all went on to nonunion, suggesting that type-II fractures should be treated by internal fixation.
High complication rates and technical difficulties of intra-medullary fixation in children with osteogenesis imperfecta has prompted the modification of existing rod systems. The Sheffield telescoping intramedullary rod has T-piece which is permanently fixed and is expanded to reduce metaphyseal migration. This study analyses the outcome of this rod system over an 11-year period.
32 rods were inserted in the lower limbs of 11 children with osteogenesis imperfecta. All children had multiple fractures of the bones before rod insertion.24 rods were inserted into femur, of which 3 were exchange procedures for complications. 8 rods were inserted into tibia. 4 children had intramedullary rodding of all the 4 lower limb bones. The outcome was measured in terms of mobility status, incidence of refractures and rod related complications. Complications encountered include 2-rod migrations, one instance each of broken rod, bent rod and valgus drift in the tibia.There was no instance of epiphyseal damage or growth arrest.
Our series demonstrates that there is significant reduction in refractures and improvement in the mobility status in children with osteogenesis imperfecta following intramedullary fixation. The frequent complication of T-piece separation and the need for reoperation has been overcome with Sheffield modification of rod design. Though the incidence of rod related complications remain high, our study concludes that Sheffield rod system compares favourably with the existing intramedullary devices for osteogenesis imperfecta in the literature.
Severe acetabular fractures are difficult to treat. Complications include blood loss, neural damage, long operating times, and a high risk of sepsis and failure. Even when the fracture is ideally stabilised, there is a major risk of secondary osteoarthritis. This can be related to bone necrosis, cartilage surface damage, bone loss.
However, even in young patients modern surgical techniques, including use of an alumina-against-alumina bearing, may facilitate long-term survival without limitation of activity.
Functionally, the results of secondary procedures after failed osteosynthesis are statistically worse than after primary total hip arthroplasty (THA). The surgery is difficult because of material retrieval difficulties, nerve dissection, bone reconstruction and remaining muscular dysfunction.
We reviewed the results of 80 THA procedures done between 1980 and 1998 to treat 58 acetabular fractures. The mean age of our 57 patients (39 men and 18 women) was 50 years (21 to 80). The mean delay between fracture and THA was 10 years in 22 patients who had undergone osteosynthesis and six years in 35 patients who had been treated conservatively. The mean follow-up period was 5,5 years (6 months to 20 years).
There were eight instances of socket loosening, two of which were septic and six aseptic. Two of these patients had screw-in prostheses and six had cemented. There were 19 sciatic palsies, 13 of which developed after trauma, four after osteosynthesis and two after THA. There were three cases of gluteus medius palsy. In two of four cases of sepsis that occurred after osteosynthesis, sepsis recurred after THA, and in one patient sepsis developed after THA.
In this limited series, patients who underwent THA after osteosynthesis did not have as good an outcome as those in whom initial orthopaedic treatment was followed some weeks later by THA. We believe many poor results could have been avoided with better primary surgery. Functional results are likely to be better, and the incidence of complications lower, if primary THA is performed in conjunction with acetabular reconstruction. Of course, for treatment of simple acetabular fracture involving major displacement of the posterior wall, one column osteosynthesis is still recommended.
We want to prove that you cannot make a good fitting stem of a THP before surgery because the resulting shape of the femoral cavity is set after all the tools have been introduced in the femur.
We are fully aware that fit and fill alone is not enough to obtain good fixation therefor all the investigated implants were plasma spray coated with HA.
We’ve investigated two groups of patients:
Pre-operative group: custommade implant based on CT scans and manufactured before surgery The proximal part was size for size and coated with HA; the distal part is cylindrical (44 cases, followup from 1.6 years to 5.2 years) Per-operative group: custommade implants based on a mould of the femoral cavity in the proximal femur and manufactured during surgery. The prosthesis was size for size and the HA coating was applied on the proximal 1/3 of the implant. (13 cases, with a minimum followup 1 year).
The coating specifications for both groups were exactly the same.We’ve compared the Harris hip score for both groups and we’ve performed a radiolographical analysis.
Of the pre- operative group 6 protheses had to be revised.This results in a revision rate of 25 % which is not acceptable.In the peroperative group however, no revisions have been performed.
Radiografically the per-operative group showed much better results than then the pre-operative group.
The obtained results suggest that it is not only important to have a good bone growth initiator such as HA but the implant needs to be in close contact with the bone.This confirms the limited gap bridging capacity of HA which has been reported by several authors in the past. A close fit can only be obtained by designing and manufacturing the implant during surgery based on the actual size of the femoral cavity.
This study investigated the effects of wear particles, produced from a number of implant materials, at the bone-implant interface using a small animal model.
Particles were prepared from metal, ceramic and polymer replacement joint components or implant grade stock by grinding the materials against a diamond embedded grinding pad. The mean diameter of the particles ranged from 1.5mm to 3.2mm. Sterilised particles were suspended in sterile saline containing 2% v/v male Sprague-Dawley serum at a concentration of 109 particles per ml.
Seventy-two male Sprague-Dawley rats were assigned to twelve groups of six animals. A ceramic pin was inserted into the right tibia of each animal. Six groups were assigned a particle type with one group acting as vehicle control. 100ml of particle suspension or vehicle was injected into each knee joint at 8, 10 and 12 weeks following implantation and the animals were killed 2 weeks later. Of the remaining five groups, four were assigned a particle type and one was the vehicle control. These animals were injected with 100ml of particle suspension or vehicle at 20, 22 and 24 weeks following pin implantation and were killed 2 weeks later. The tibia and femora were removed, disarticulated and processed for histology. The total gap between pin and bone, including fibrous tissue, was measured.
Specimens showed no signs of infection either clinically or in the histopathology. All materials tested produced lesions at the bone-implant interface. A significant difference was seen between metal injected vs. vehicle control animals and aluminium oxide injected vs. vehicle controls. Particles of stainless steel produced the greatest response and this finding may have implications for the use of metal on metal articulations aimed at eliminating polyethylene wear.
Two calcium phosphate cements, brushite and hydroxyapatite, have been recently developed as bone substitution materials. The brushite cement is biocompatible, resorbable, osteoconductive and injectable since it hardens in physiological conditions. In contrast, hydroxyapatite is less resorbable and is not injectable. However, hydroxyapatite presents a higher strength, which may open the perspective of use in weight-bearing regions of the skeleton subjected to multi-axial stresses. The purpose of this work is a full characterization of the multiaxial elastic and failure behaviour of these two cements in a moist environment.
The brushite cement was prepared by mixing three phosphate powders in presence of water. A mixture of monetite and calcite powders in presence of water was used to obtain hydroxyapatite self-setting cement. Cylindrical, hollow specimens (Øext=18mm, Øint=14mm, L=40mm) were manufactured to apply uniaxial and torsional deformations. The specimens were cast with a custom mould, avoiding any machining, and thus, residual stresses. Scanning electron microscopy and x-ray diffraction were used to examine the cement microstructures and to determine their final material phases. An MTS axial-torsional machine was used for all mechanical tests. Compression, tension and torsion tests were performed each on five brushite and five hydroxyapatite specimens under moist conditions. Uniaxial and biaxial extensometers were used to measure the elastic moduli and the Poisson ratio.
The brushite cement exhibited failure properties comparable or below those of average human cancellous bone and confirmed its indication as a bone filling material (Brushite failure strength : 1.3±0.3 MPa in tension, 2.9±0.4 MPa in shear and 10.7±2.0 MPa in compression). The hydroxyapatite cement had an order of magnitude larger compressive strength (75±4.2 MPa), comparable tensile (3.5±0.9 MPa) and shear (4.8±0.3 MPa) strengths as average human cancellous bone. As expected, the latter cement seems to be more compatible with a multiaxial weight-bearing function in bone substitution.
We have long suspected that patients treated at our institution have narrower femoral canals than the literature suggests. This has implications when it comes to nail size and the question of using reamed or unreamed nails. Using CT analysis, we studied the morphology of the femoral isthmus.
We prospectively evaluated 30 men with a mean age of 26 years (20 to 35). Patients with previous femoral fractures were excluded from the study. A scanogram determined the level of the isthmus and axial cuts at this level accurately revealed canal size and shape.
We found a canal size of less than 12 mm in 62%. In a third of these, canal size was less than 11 mm. Axial cuts showed three types of femoral canals: 14 patients had thick femoral cortices and a narrow canal, seven had thin cortices and a wider canal, and nine had an oval canal, with the larger diameter in the sagittal plane.
If one adheres to the principle of reaming until cortical clutter is heard, the recommended 12-mm or 13-mm reamed femoral nail is not suitable for the majority of non-Caucasian men in our population. Larger nails may cause such complications as delayed union, nonunion and fracture. Smaller nails of 10-mm and 11-mm diameter result in satisfactory clinical and radiological outcomes.
In a retrospective study, we examine the occurrence and management of sepsis in total knee arthroplasty. Histological examination and MCS play important roles.
In the past many high tibial osteotomies were done to relieve symptoms of osteoarthritis. Total knee arthroplasty (TKA) has largely taken the place of these osteotomies.
Aiming to evaluate the long-term results of these osteotomies and assess the complications involved on conversion to TKA, we followed up 207 patients over a 10-year period.
Fractures of the thoracolumbar spine are now so common that most orthopaedic surgeons are likely to have to handle one. It is important that we have common terms of reference when we assess, manage and discuss outcomes of these injuries.
The authors plan to assess the intra-observer and inter-observer interpretation of six plain radiographs of thoraco-lumbar fractures. Volunteer orthopaedic surgeons attending the SAOA Congress will be asked to classify the six radiographs twice, on different days, and the radiographic labelling will be changed. Participants will be given the Margel and Dennis classifications for reference. Participants’ names will not be required, only their year of qualification and exposure to spinal surgery.
The results will be analysed statistically and communicated to the orthopaedic community in due course.
Lisfranc injuries make up 0.2% of all fractures. With or without midfoot injuries, treatment requires early accurate diagnosis, anatomical reduction and stable internal fixation. Some surgeons prefer K-wire fixation, while others rely on rigid screw fixation, especially of the medial column. To assess the radiological and functional outcome of K-wire fixation of Lisfranc injuries, we carried out a prospective study between January 1999 and December 2000.
The ages of our 15 male and four female patients ranged from 15 to 47 years. Using the Quenu and Kuss system to classify injuries, we treated five isolated, nine homolateral and five divergent injuries. In eight patients there were associated midfoot injuries, and four had compound fractures. We treated 11 fractures with closed reduction and K-wires. Open reduction with K-wire fixation was carried out on eight fractures, including the four compound fractures, within 19 days of admission. All patients were kept non-weight-bearing in a short backslab, and the wires removed at six weeks. Follow-up times ranged from 4 to 19 months.
To assess functional outcome we used the American Orthopaedic Foot and Ankle Society’s midfoot scoring system, which has a maximum score of 100. The mean score of our patients was 70 (52 to 85). Mild or occasional foot pain and slight gait abnormality resulted in limitation of recreational activities. At three months, 15 patients were fully weight-bearing. A single case of superficial sepsis resolved, and there were no cases of implant failure or loss of reduction.
K-wire fixation following anatomical reduction is a satisfactory option for the treatment of tarsometatarsal injuries, especially when severe injuries involve the midfoot. The technique is minimally invasive and the K-wires are easily inserted and removed.
Method: Six TKRs in young, active patients with excellent Oxford Knee Scores and Knee Society Scores, mean 76 months post knee replacement and 5 control patients, 2 weeks post TKR, were selected. Each patient had weight bearing stereo radiographs of at 0, 15, 30, 45 and 60 degrees of flexion while standing in a calibration grid. These x-rays were analysed using our Radio Stereometric Analysis (RSA) system. The three-dimensional shape of the TKR (manufacturer’s computer aided design model) was matched to the TKR silhouette on the calibrated stereo radiographs for each angle of flexion. The relative positions of the femoral and tibial components in space were then determined and the linear and volumetric penetration was calculated using Matlab software.
*Oxford Hip and Knee Group: P McLardy-Smith, C Dodd, D Murray & R Gundle
The objective of our research is to elucidate the pathogenesis of soft-tissue contracture. Here we present a comparison of collagens isolated from deltoid ligament of 23 clubfeet classified according to the Dimeglio-classification and of 14 matched controls of normal feet.
Collagens were isolated by acetic acid extraction and by limited pepsin-solubilisation and analysed by SDS-PAGE. Ligaments and solubilised collagens were analysed for their extent of hydroxylation of prolyl- and lysyl-residues, their content of galactosyl-hydroxylysine and glucosyl-galacto-syl-hydroxylysine and their content of lysyl-oxidase dependent cross-links histidinohydroxylysino-norleucine (HHL), hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP). Analysis were carried out using an amino acid analyser (Bio-chrom 20, Amersham Pharmacia Biotech) and a reverse-phase HPLC system (Gynkothek).
Percentage of collagen of total protein decreases in club-foot as compared to controls. SDS-PAGE of solubilised collagens shows a high content of type I, less of type III and small amounts of type V collagen in both groups. The extent of hydroxylation of proline appears to be very similar, whereas the degree of hydroxylation of lysine follows the Dimeglio-classification. In addition, glycosylation of hydroxylysine increases parallelly to the classification. However, the increase is found solely in the amount of disac-charides. Total content of HHL, the most important collagen cross-link in soft tissues, was increased significantly in club-feet as compared to controls. HP, the hard tissue specific collagen cross-link was increased slightly in clubfeet. Levels of LP were too low to detect differences precisely.
The data presented show distinct differences in the post-translational modifications of collagen (hydroxylation of lysyl-residues, glycosylation and lysyl-oxidase dependent cross-links) isolated from congenital idiopathic clubfeet and from controls.
We retrospectively reviewed 100 consecutive cases of foot trauma, sometimes accompanied by other injuries, in people who had instituted legal proceedings to recoup losses after motor vehicle accidents. To keep matters in their correct perspective, it must be noted that claims on a contingency basis were not acceptable at the time of this review.
We excluded from the study patients with only minor foot injuries and significant other injuries. There was significant foot trauma in 14% of the reviewed motor vehicle accident cases, and 75% of patients had significant other injuries. Of patients who had suffered only foot trauma, 32% were male and 68% female. Their mean age was 36 years and the review was conducted a mean of 28 months after injury. Of those who suffered multiple injuries, 65% were male and 35% female. Their mean age was 34 years and the review conducted a mean of 21 months after injury. Combining the effects of patients’ other injuries but reviewing foot injuries separately, we assessed the long-term impact of the injuries as minimal, slight, moderate, severe or very severe. Nearly 50% of the foot injuries had a severe or very severe long-term impact, involving loss of amenities of life and the ability to earn a living. In 44% of the multiple trauma cases, the foot injury alone would cause significant loss of income. In about 30% of these cases the other injuries would have a similarly negative effect. We estimated that 60% of foot injures and 40% of other injuries would later come to need surgical treatment.
When we assessed the quality of care the patients received, we found that 50% of those with only foot injuries and 40% of those with foot and other injuries had not been given optimal treatment for their foot injuries. In 15% of cases the other injuries could have received better treatment.
Our review showed that foot injuries sustained in motor vehicle accidents can have serious long-term effects. However, because they are not life-threatening, at the time of the accident foot injuries receive suboptimal treatment. In multiple trauma patients, foot injuries should not be overlooked. Optimal treatment will improve the final outcome and enjoyment of life of motor vehicle accident victims.
Unicompartmental knee arthroplasty has been in use since the 1970s. In spite of early enthusiasm, the procedure soon fell into disfavour, particularly in the USA. Early failures were a result of improper indication, poor technique and in some cases and poor prosthetic design.
A new instrument system for use with the MG unicompartmental knee arthroplasty has been designed, with guides for accurate and reproducible alignment, sizing and resection. Potential benefits include early mobilisation, rapid rehabilitation, improved range of motion and shortened hospital stay.
This paper briefly reviews the literature and discusses indications and surgical techniques.
We review our first 100 LCS rotating platform total knee arthroplasty (TKA) procedures. Done between July 1993 and December 1996, they are currently at four to seven year follow-up.
The sample includes 100 TKAs done in 88 patients as unilateral or bilateral procedures. At operation the mean age of patients, 51% of whom were female and 49% male, was 67 years (47 to 84). The right side was replaced in 54% of cases and the left in 46%. Preoperative diagnoses included degenerative and post-traumatic osteoarthritis in 95 knees and rheumatoid arthritis in five.
Two assessments are currently being carried out. They include the American Knee Society Clinical Rating Score, functional ability and radiographic evaluation of knee alignment and radiolucencies. Mean clinical and functional Knee Society ratings were 38 and 57 (sum 95 points) preoperatively and 88 and 84 (sum 172 points) postoperatively. Radiographs showed valgus alignment in 90 rays and varus alignment (1° to 7°) in 10. Limited areas of radiolucency were seen around three tibial components. Two cases have required revision, one for septic loosening and one to correct recurrent varus deformity.
Although an increased and deeper innervation of painful and degenerate intervertebral discs (IVDs) has been reported, the mechanisms that regulate nerve growth into the IVD are largely unknown. In other tissues, proteoglycans have been found to act as nerve guidance molecules that, generally speaking, inhibit nerve growth. As disc degeneration is characterised by a loss of proteoglycans, we assessed the effects of IVD proteoglycans on nerve growth and guidance.
Using in vitro assays of nerve growth, we found that human disc proteoglycans inhibited nerve attachment, neurite extension and induced sensory growth cone turning in a dose-dependent manner. Digestions with chondroitinase ABC or keratinase abrogated these inhibitory effects. Proteoglycans of the anulus fibrosus were more inhibitory than those from the nucleus pulposus.
Disc proteoglycans inhibit nerve growth and this inhibitory activity may dependent on proteoglycan glycosylation and/or sulfation. A loss of proteoglycans from degenerative discs may therefore predispose the discs to nerve invasion.
One million patients with head injuries present to UK hospitals each year. A significant proportion of these patients have ongoing problems and a large number remain disabled at one year. The management of these patients has recently been criticised by a Royal College of Surgeons Working Party Report (published in June 1999). Several recommendations for the care of head injured patients were made.
We have undertaken a study to examine the way these cases are currently dealt with in Welsh hospitals. A large proportion (75%) of these patients in Wales are cared for by non-neurosurgical consultants with the orthopaedic speciality receiving referrals in most hospitals (55%). A questionnaire was sent to these non-neurological consultants looking after head injuries with specific questions on the current care of these patients and for their opinion on the current system.
We have received an excellent response rate (99%) with the results showing that the Working Party recommendation have not been translated into a change in clinical practice. Our study indicates several shortcomings in the current care of these patients in Wales. It also demonstrates that the almost unanimous (98%) view amongst the consultants that responded is that there is a genuine need for change if we are to offer these patients the best care and rehabilitation in the 21st Century.
A review of scientific literature on whiplash associated disorders was conducted to inform appropriate messages for an evidenced based patient educational booklet, “The Whiplash Book.” The booklet is being developed for use as both a clinical tool and general health intervention.
A systematic literature search was conducted, using MEDLINE and psychINFO, together with hand searches, reference tracking, and the Internet. The Quebec Task Force report and the British Columbia Whiplash Initiative were taken as the starting point. The new evidence covered the period May 1994 through March 2001 (147 articles). All relevant articles were included, with a particular focus on management and treatment of whiplash associated disorders. The quantity, consistency and relevance of all retrieved articles was evaluated, and rated as *** for consistent findings in multiple reports, ** for consensus based on balance of various findings, or * for limited information (single report).
The main messages from the literature suggest: physical serious injury is rare, reassurance about good prognosis is important, over-medication is detrimental, fastest recovery occurs with early return to normal pre-accident activities, self-exercise/manual therapy and positive attitudes/beliefs are helpful to regain activities levels, collars/rest and negative attitudes/beliefs delay recovery and contribute to chronicity.
The material most widely used in orthopaedics is hydroxyapatite (HA), anyway many differences are still present between synthetic HA and biological HA. The aim of this study was to compare adhesion, proliferation and differentiation of human osteoblast-like cells on hydroxyapatite discs with different porosity and on plastic cultures.
Human osteoblast-like cells were isolated from 4 young patients (mean age 24.5 years old), treated with collagenase and maintained in Dulbecco’s modified essential medium-10% fetal calf serum. Cells were plated on hydroxyapatite discs with 3 different porosities (35%, 35–55% e 55%) and on plastic cultures used as control. The proliferation was determined by the MTT colorimetric method, and alkaline phosphatase (ALP) activity was measured by a spettrophotometric method. Type I collagen and osteonectin production were demonstrated with fluorescence microscopy and osteoblast adhesion was studied by scanning electron microscopic (SEM) analysis. Results were analysed by one-way analysis of variance (ANOVA).
Osteoblast proliferation on HA was three- to six-fold lower then on plastic. At 28 days, 2141 (± 350) cells/well grew on the most porous disks, with highly significant differences from controls. The ALP production was 2–3 fold lower on HA than on plastic. In the most porous disks, the mean ALP activity was of 2.95 (± 0.07) UI/well after 28 days, higher than in the other two groups. The type-I collagen and the osteonectin fluorescence reaction evidenced a cytoplasmic and a matrix labeling on HA at different porosities. SEM analysis showed osteoblasts with a flattened morphology and only few of them were metabolic active.
At 21 and 28 days, proliferation rate and ALP activity on the three HA cultures were significantly different (p< 0.05). A decrease in cell population and increased ALP activity were observed on the most porous material, and high proliferation and poor differentiation rates on the less porous disks.
Osteoarthritis (OA) is one of the most prevalent diseases of the elderly, affecting greater than 50% of the population over 60 years of age. Many factors are implicated in the development of OA but currently no mechanism has been described that provides an explanation for age as the major risk factor for OA. The present studies were designed to investigate the hypothesis that age-related accumulation of advanced glycation endproducts (AGEs) provides a molecular mechanism that explains (at least in part) the age-related increase in the incidence of OA.
To gain insight in the diversity of AGEs present in articular cartilage, several AGE measures were determined in a wide age-range of normal human articular cartilage samples: all demonstrated increased AGE levels with increasing age. The level of these AGEs was high in cartilage compared to other tissues such as skin, which is mainly caused by the very low turnover of the cartilage matrix proteins. The t1/2 of collagen in articular cartilage is ~117 years (compared to t1/2 of skin collagen of ~15 years).
Accumulation of AGEs in cartilage affected biomechanical, biochemical and cellular characteristics of the tissue. At the biomechanical level, increased AGE levels were accompanied by increased stiffness and brittleness, indicating that AGE accumulation leads to increased susceptibility of articular cartilage to mechanical damage. On the cellular level, accumulation of AGEs decreased the synthesis and degradation (= turnover) of the cartilage matrix. Such decreased cartilage turnover is likely to result in decreased repair capacity of the tissue.
In combination, the AGE-related increase in tissue brittleness and decrease in extracellular matrix turnover, results in articular cartilage that is more prone to damage. This concept, that AGE accumulation predisposes to the development of OA was tested in the canine anterior cruciate ligament transection (ACLT) model for osteoarthritis. Selectively enhancing AGE levels in articular cartilage of young animals (in the absence of other age-related changes) resulted in more severe OA.
Altogether, AGE accumulation in articular cartilage presents a molecular mechanism by which ageing predisposes to the development of OA, and it provides new possibilities for prevention and/or therapy via the inhibition and/or reversal of cartilage AGE formation.
In this outcome-based study, we reviewed the results of the modified Woodward procedure performed on 10 patients over the last 15 years in our unit. The indication for surgery was a unilateral Sprengel’s deformity, Cavendish grade II or III, in children aged 3 to 6 years. Follow-up times ranged from 1 to 15 years. The patients were assessed according to patient and relatives’ satisfaction, cosmesis and functional results.
The modified Woodward procedure entailed a midline longitudinal incision over the spinous processes from C1 to T8. The origins of the trapezius and rhomboids were released from the spinous processes, the scapula lowered and derotated, the superomedial portion of the scapula resected and the trapezius and rhomboids reattached two vertebral levels lower. The clavicle was not osteotomised in any patient. A Velpeau sling was used for four weeks, after which physiotherapy was started.
There were no brachial plexus complications. There were two cases of winging of the scapulae. One patient had a cosmetically ugly scar. Our results showed a cosmetic improvement by an average of one grade and a mean functional improvement of 30° of abduction and flexion. Those patients where an omovertebral body was found and resected had the best cosmetic and functional results. All the patients were satisfied with their operations.
We feel that the pessimism regarding surgical results is unwarranted.
Which of several osteotomies described for approximation of the pubic bones in wide congenital diastasis of the pelvis best facilitates closure is controversial. This paper describes the benefits of the horizontal innominate osteotomy in approximation of the pubic bones when there is wide congenital diastasis.
Between 1994 and 2000, 11 children, ranging in age from one week to eight years, were treated by horizontal innominate osteotomies. Six children had exstrophy of the bladder. There were ischiophagus tetrapus twins and cases of duplication of the genitalia and sacral teratoma. The follow-up time ranged from six months to six years.
General surgical procedures were followed by bilateral innominate osteotomies to facilitate approximation of the pubic bones for bladder, genitalia and anterior abdominal wall repair. The ilium was exposed subperiosteally with the patient supine. A Salter-type osteotomy was performed, dividing the innominate bone from the sciatic notch to just above the anterior inferior iliac spine. The distal fragments were rotated medially, the pubic bones approximated in the midline, and the surgical soft tissue procedures completed. Postoperatively, children were maintained in gallows traction for two weeks and immobilised in plaster for four further weeks.
All osteotomies healed well. Abdominal wound infections occurred in two children, resulting in separation of the pubis. One child had repeat osteotomies one year later and healed well. Abdominal wall hernia occurred in one child. The gap between the pubic bones in the remaining patients ranged from 1cm to- 5 cm. Internal rotation of the hip improved in all patients.
Horizontal iliac osteotomies enable complex pelvic malformations to be corrected without turning the patient. The approximation of the pubis relieves the tension for reconstruction of the bladder, urethra, genitalia and anterior abdominal wall. The procedure is quick and permits single stage closure.
Ceramic-ceramic (C-C) bearings have 20 years clinical experience with alumina ceramics. This system is re-emerging because of its demonstrated excellent wear performance compared to metal-PE or ceramic-PE. However, alumina ceramic imposes a design limitation to reduce breakage risk: most of the implanted C-C systems present a head larger than 28 mm. Zirconia ceramic is three-times more mechanically resistant and has proven its efficiency in ceramic-PE couple. As a result, a new C-C bearing with zirconia head has been studied. Excellent wear performance of the zirconia-alumina (Z-A) combination system has already widely been proven through multilaboratory experiments on a hip simulator. The mechanical aspect is investigated here to analyse the benefit of a zirconia head in a C-C system. This aspect has been first studied by Finite Element Analysis (FEA) and then validated by experimental testing.
The first series of tests on the 28mm system confirmed the FEA predictions: the breakage loads were correctly estimated for each assembly, showing that FEA is an effective tool to predict breakage load and location. The second series of tests were performed on 22.22mm systems. FEA predicted that the Z-A system should pass the 46 kN contrary to the A-A system. Breakage of the A-A system is expected to be in the head.
In conclusion, Z-A combination offers higher mechanical security for the existing C-C designs but above all, larger design choice than A-A system. Considering that wear performances are equivalent, the Z-A system can be thought as the logical evolution of A-A system.
Osteoporosis and osteoporotic fractures represent a growing medical and socioeconomic problem and the spine is the most common site for this kind of fracture. Back pain is the leading symptom with progressive loss of stature and restricted physical activity as a consequence. Vertebroplasty – percutaneous cement reinforcement of osteoporotic vertebrae - represents a new treatment alternative.
During a three year period, 512 vertebrae in 180 patients were reinforced for osteoporotic fractures with low viscosity PMMA. One to eight levels were treated per time, and 8ml (2–18ml) of PMMA per vertebra were injected. The patients’ pain (VAS) was prospectively monitored before surgery, one day, 3 months and one and two years postoperatively. Furthermore, X-rays were analysed 3, 12 and 24 months postoperatively.
One out of 180 patients suffered from an L2 root irritation due to cement leakage that subsided after steroid infiltration. 52 patients with 144 levels treated and a minimal follow up of two years showed a significant (p< 0.02) and lasting pain reduction from 7.7 to 2.8 points at two years. 6 patients were treated a 2nd time for a new fracture. The reinforced vertebrae remained stable without further sintering.
Vertebroplasty is efficient for the treatment of osteoporotic vertebral fractures. The injection technique used is safe, easy and fast. An unsolved problem remains the question about the importance of prophylactic reinforcement of non-fractured vertebrae.
Osteoporotic vertebral fractures are normally attributed to weakening of the vertebral body. However, the compressive strength of the spine also depends on the manner in which the intervertebral disc presses on the vertebral body, and on load-bearing by the neural arch. We present preliminary results from a large-scale investigation into the relative importance of these three influences on vertebral compressive strength.
Lumbar motion segments from elderly cadavers were subjected to 1.5 kN of compressive loading while the distribution of compressive stress was measured along the antero-posterior diameter of the intervertebral disc, using a miniature pressure-transducer. The overall compressive force on the disc, obtained by integrating the stress profile (
A univariate analysis of results from the first 9 motion segments (aged 72–92 yrs) showed that vertebral strength increased from 2.0 kN to 4.6 kN as the compressive force resisted by the neural arch in erect postures decreased from 1.1 kN to 0.4 kN (r2 = 0.42, p = 0.05). Updated results from this on-going study will be presented at the meeting.
Preliminary results suggest that habitual load-bearing by the neural arch in erect postures can lead to progressive weakening of the vertebral body, which is effectively “stress-shielded” by the neural arch. This weakening is exposed when the spine is loaded severely in a forward stooped posture, when it has a reduced compressive strength. This mechanism could explain some features of osteoporotic vertebral fractures in old people.
Anatomisches Institut der Georg-August-Universität Göttingen, Germany
Biomedical Research Centre, Dept. of Orthopaedic Surgery, Academic Hospital, Pretoria, South Africa
To date, no animal model for disc degeneration has gained much acceptance, mostly due to the fact that most animals are quadrupeds and thus lack basic biomechanical characteristics of human spines. An adequate model would be of invaluable interest for degeneration related research.
In a standardized series of animal experiments in 18 adult Minipigs and 20 adult Cercopithecus aethiops monkeys all animals obtained nucleotomy in one lumbar FSU from a ret-roperitoneal approach and were sacrificed at last 24 weeks afterwards. The Minipigs were x-rayed at time of sacrifice, the monkeys prior to operation and at termination of the experiment. Vice versa, the Minipigs obtained intradiscal pressure recordings at these occasions. The Minipig spines were formol fixed whereas the monkey spines were harvested after perfusion with PBS, fresh frozen, and obtained CT and MRI scans prior to thawing, fixation and comprehensive histological evaluation.
The lumbar FSU of Minipig and Cercopithecus mainly consists of the same elements as in man. There are certain differences concerning the porcine endplates which ossify as an epiphyseal-like formation with ossification starting in its center, different from the so-called “Randleiste”. Whereas the operative procedure in the Minipigs came in handy, in the Cercopithecus monkey it proved to be demanding, though feasible, due to relatively wide transverse processes and thick psoas muscle structures. The psoas could not be easily detached and needed to be split instead, thus directly exposing the segment nerves. The histological, standard radiological, CT, MRI, and mechanical observations were very similar to those which can be made during the natural aging process of the disc in man.
Both animal models are recommendable for further research: Cercopithecus FSUs are more difficult to expose. Logistic reasons may favour Minipigs in Europe. In case of fusion related experiments the use of primates yet seems inevitable.
We report on four cases in which the diagnosis of compartment syndrome was delayed by the administration of patient controlled opiate analgesia ( PCA ) following intramedullary nailing of tibial shaft fractures. We believe that this poses a diagnostic problem and can lead to lasting sequelae as decompression is delayed. We present the 4 cases and a review of the literature. We recommend that the use of PCA in patients with intramedullary nailing following tibial shaft fractures be discontinued or used in conjunction with continuous intracompartmental pressure monitoring.
The purpose of this study: is to test the hypothesis that there is little or no stress shielding afforded by a carbon composite femoral hip prosthesis when implanted in the human subject, and to investigate the possibility that a hydroxyapatite coating would prevent loosening.
The need for this development: is that loosening remains a problem for young patients who need a long term, reliable fixation of hip replacements, and it appears that if a solution exists to this problem then it probably lies away from the traditional cemented metal varieties.
One of the causes of loosening is stress shielding caused by rigid metal implants and a carbon composite femoral stem has been developed to overcome this. Paradoxically, flexible stems result in increased micro-motion at the prosthetic-bone interface and as a result they tend to loosen more frequently than metal ones. To overcome this, the carbon stem has been coated on its proximal third with hydroxyapatite, in order to get a secure fixation to the upper femur, but left bare distally to minimise weight transfer within the lower shaft.
Bone density around the carbon composite hip was found to increase by an average of 2% between the measurements carried out at 1 and 2 years post-op. In the contralateral hip, bone density remained unchanged over the period. Bone density around comparable metal stems reduced by an average of 3% in our cases, but losses over 20% are quoted by others especially for zones 1&
7. Follow up is very short for responsible prognosis to be offered regarding loosening, but to date the function of the hips remains good.
Clinically asymptomatic. Progress to a wider trial can now be recommended.
Glycosaminoglycans (GAGs) govern the osmotic environment of cartilaginous tissues and hence determine their ability to resist the large compressive forces encountered during normal activity. In degeneration GAGs are lost and there is now much interest in biological repair processes where cells from cartilaginous tissues synthesise replacement GAGs and other matrix components in situ. In addition, cells can be grown in tissue engineered constructs. Unfortunately, GAG synthesis is slow.
The aim of this study was to determine whether GAG accumulation could be hastened by increasing cell density in a construct using articular cartilage and intervertebral disc cells cultured in alginate beads.
Bovine chondrocytes and intervertebral disc cells were placed in alginate bead suspension at varying cell densities. GAG synthesis rates, total GAG accumulation and lactate production rates were determined by standard methods. The cell viability profile across intact beads was determined using fluorescent probes.
Increasing cell density causes a reduction in lactate production and sulphate incorporation per million live cells. At greater than 20 million cells per ml, cell death is increased compared with lower densities. GAG produced per bead is not increased in proportion to increasing cell density.
These results show that there is a limit to the rate at which matrix per volume of tissue can be produced and accumulated. At high cell densities cellular activity is limited by toxicity arising from low pH and hypoxia.
One of the mechanisms which controls bone growth, repair remodeling and absorption is mechanical loading. There exists no long-term in vitro model to study bone cells together with their matrix, nor a model that can apply quantitative mechanical forces of physiological amplitudes and frequencies. The analysis of the mechanical properties of bone (Young’s modulus and visco-elastic moduli) on small pieces of bone is also difficult with present devices. We have built a device that can maintain full viability and physiological response of bone for a period of several weeks and integrates all three functions.
10mm diameter bone cores 5 mm thick were obtained from the trabecular bone of the distal ulna of a 24 months old cow by precision cutting with diamond saws and keyhole cutters (our pattern) in sterile 7–10°C phosphate buffered saline (PBS) and cultured in a variation of DMEM containing fructose HI GEM.
We gratefully acknowledge support by the German Arthrose Foundation (DAH) and the AO in Davos, CH.
During forward bending activities, the collagenous tissues of the spine are protected from injury by reflex contractions of the back muscles which prevent excessive spinal flexion. Animal experiments have shown that this reflex response is diminished when spinal ligaments are subjected to creep (
Ten healthy volunteers (4M/6F) consented to participate in the study. Subjects underwent two flexion treatments: i) prolonged sitting in a low chair for 2 hours, ii) 100 toe-touching exercises, each on a separate day. Before and after each treatment, subjects performed a standardised forward bending task during which simultaneous measurements were made of lumbar flexion, using the 3-Space Fastrak, and surface EMG activity of the erector spinae muscles at T10 and L3 (
Both treatments caused creep, as indicated by a significant increase in the range of lumbar flexion. The treatments also brought about a significant delay in the reflex activation of the back muscles in the standardised bending task: after prolonged sitting, lumbar flexion during the bending task increased by 9.2 ± 7.4° and 5.7 ± 4.6° before the onset of EMG activity at T10 and L3 respectively; following the toe-touches, the equivalent increases in lumbar flexion were 5.4 ± 3.9° and 3.1 ± 4.4°. The amplitude of the reflex response was unchanged following prolonged sitting, but after the toe-touches, a 50% increase in peak EMG activity was observed at L3.
Creep in spinal tissues as a result of prolonged or repetitive flexion was associated with delayed reflex activation of the back muscles. There was no associated reduction in the amplitude of the reflex. The increase in peak EMG activity following the toe touches may reflect increased activation as a result of muscle fatigue. These results suggest that creep in spinal tissues may allow increased lumbar flexion and hence increased bending stresses to be applied to the intervertebral disc.
Paraspinal muscle dysfunction is associated with chronic low back pain (CLBP) in prospective studies, some authors suggesting a primary role for muscle in CLBP development. To investigate this possibility, we compared paraspinal muscle electromyographic (EMG) fatigue characteristics with fibre-type composition in ambulant, male CLBP patients and male controls of similar age.
Thirty-five patients with Chronic Pain Grades of III (a high level of residual function, despite pain, negated the effects of disuse atrophy), and 32 controls were studied. Paraspinal surface EMG signals were recorded from the T10/11 and L4/5 regions bilaterally during standard isometric endurance tests. The rate of fatigue-induced median frequency (MF) decline was calculated from the power spectrum. Percutaneous paraspinal muscle biopsies permitted the determination of muscle fibre-type characteristics.
MF decline, mean fibre size and relative area occupied by fibre types did not differ significantly between groups.
The paraspinal muscles of ambulant CLBP patients demonstrate no excessive fatigability, when assessed by EMG, nor a relative paucity in the area occupied by either fibre type. Patients developing CLBP do not demonstrate an adverse paraspinal muscle fibre-type composition.
For many years, it has been taught that the human knee is a ‘hinge’ joint and that the motion of the knee is controlled by a ‘four-bar link’. This classic view of the motions of the knee suggests that there is a prescribed path for the knee as it proceeds from extension to flexion and flexion to extension. This prescribed motion includes ‘rollback’, a term used for the progressive posterior displacement of the femur on the tibia as the knee moves from extension to flexion,
Most of the total knee prostheses available today have been designed to permit the movements that are required by this model of knee motion. The design features necessary to permit this motion are a lack of constraint between the tibial and femoral components, and a ‘J’ curve of the posterior part of the femoral component such that the radius of curvature is smaller on the posterior portion of the component than on the distal part.
Studies of the anatomy of the knee date back to the 1800s, before radiological studies were possible. Radiological evidence does not support the four-bar link and rollback theories or indicate that a ‘J’ curve is necessary. Rather, radiographs suggest that the knee is more of a ball-in-socket joint on the medial side with little or no rollback in normal function. Three-dimensional studies of the moving human knee both in vitro and in vivo also demonstrated that the knee joint moves as a ball-in-socket joint on the medial side, and that the lateral side displaces posteriorly or anteriorly as necessary to accommodate the rotational position of the tibia relative to the femur.
These kinematic findings have led to the design of a pros-thesis that mimics the normal knee. The femoral prosthesis has a single radius of curvature to each condyle both in the sagittal and coronal planes. The mating tibial component has an exactly conforming geometry on the medial side leading to ball-in-socket type of kinematics. The lateral side of the tibial component allows anterior or posterior displacement of the femur, mining the normal changes that take place with internal and external rotation.
Initial clinical results total knee arthroplasty procedures performed with this prosthesis are just passing the three-year follow-up interval. There have been no reports of catastrophic problems, and surgeons have been pleased with the stability, the rapidity with which function is regained, and the excellent range of motion following arthroplasty. Patients who have a more traditional total knee arthroplasty in one knee and the medial pivot prosthesis in the other prefer the medial pivot because of the feeling of stability.