Long-term survival of a cemented titanium-aluminium-vanadium alloy straight-stem femoral component.

We present a retrospective series of 170 cemented titanium straight-stem femoral components combined with two types of femoral head: cobalt-chromium (CoCr) alloy (114 heads) and alumina ceramic (50 heads). Of the study group, 55 patients (55 stems) had died and six (six stems) were lost to follow-up. At a mean of 13.1 years (3 to 15.3) 26 stems had been revised for aseptic loosening. The mean follow-up time for stable stems was 15.1 years (12.1 to 16.6). Survival of the stem at 15 years was 75.4% (95% confidence interval (CI) 67.3 to 83.5) with aseptic failure (including radiological failure) as the end-point, irrespective of the nature of the head and the quality of the cement mantle. Survival of the stem at 15 years was 79.1% (95% CI 69.8 to 88.4) and 67.1% (95% CI 51.3 to 82.9) with the CoCr alloy and ceramic heads, respectively. The quality of the cement mantle was graded as a function of stem coverage: stems with complete tip coverage (type 1) had an 84.9% (95% CI 77.6 to 92.2) survival at 15 years, compared with those with a poor tip coverage (type 2) which had a survival of only 22.4% (95% CI 2.4 to 42.4). The poor quality of the cement mantle and the implantation of an alumina head substantially lowered the survival of the stem. In our opinion, further use of the cemented titanium alloy straight-stem femoral components used in our series is undesirable.

Comparison of four techniques for the fixation of a collagen scaffold in the human cadaveric knee.

OBJECTIVE: Four fixation techniques for a fibrinogen and thrombin coated collagen fleece, used as a scaffold in the cartilage repair, were compared simulating the initial postoperative period in the cadaveric knee joints. METHODS: Full-thickness chondral lesions were made on the medial femoral condyles of seven human cadaveric inferior extremities. Four scaffolds without seeded chondrocytes were implanted into each lesion using four fixation techniques consecutively: self-adhesion without additional material (SA), fibrin sealant (FS), bone sutures (BS), and periosteal cover (PC). After each implantation 150 cycles of continuous passive motion (CPM) were performed. Two cases were additionally exposed to 50 cycles of 10 and 20 kg loading each after the completion of CPM. The scaffolds were evaluated after every 30 cycles, and the fixation strength was tested after the motion was completed. RESULTS: All the SA scaffolds were detached before 60 cycles. The other scaffolds remained stable throughout the testing with only minor disruptions. The endpoint fixation strength was higher for BS and PC than for the FS scaffolds. The FS scaffolds were detached as a result of additional load cycles, while the BS and PC scaffolds showed substantial deformations. CONCLUSION: SA of tested scaffold did not provide sufficient fixation. The FS fixation was easy to perform and assured satisfactory scaffold stability. BS and PC provided excellent scaffold stability, but the techniques were difficult and caused additional injuries. Regardless of the fixation technique used, the tested collagen scaffold may not be exposed to loading in the initial postoperative period.

Fracture-related and implant-specific factors influencing treatment results of comminuted diaphyseal forearm fractures without bone grafting.

INTRODUCTION: Recommendations regarding the application of primary autologous bone grafting in the surgical treatment of comminuted diaphyseal forearm fractures are conflicting. Some recent studies suggested that there is no difference in the union rate between simple and comminuted forearm fractures and that the use of bone grafting in the treatment of these fractures is therefore not necessary. Our hypothesis was that among comminuted forearm fractures there is a small group of fractures with a very large extent of comminution that heal with a significantly lower union rate and a prolonged time to union compared with other fractures. We believe that in these fractures bone grafting could help to reduce the time to union and further decrease the rate of nonunion. MATERIALS AND METHODS: We reviewed the results of the treatment of 214 consecutive patients who sustained 319 diaphyseal fractures of forearm bones. To prove our hypothesis, union rate and time to union in fractures with different extents of comminution were compared. All fractures were treated by open reduction and internal fixation with plates without the use of bone grafting. In addition, the study evaluated other factors that could influence the union rate and time to union in observed fractures. RESULTS: Separate analysis of union rate and time to union in fracture groups with different extents of comminution confirmed our hypothesis only partially. Although we proved that fractures with bone loss greater than two-thirds of the diameter of the diaphysis had a significantly prolonged time to union, we could not demonstrate a significant difference in the union rate between groups. Based on these findings, we believe that primary autologous bone grafting of comminuted diaphyseal forearm fractures is not necessary in most cases. If used, its application should be reserved only for fractures where the bone loss exceeds two-thirds of the diameter of the diaphysis. Such fractures are rare; in our study, they accounted for only 5% of all fractures. CONCLUSION: The most important factors found to influence the union rate and time to union were stability of fixation and type of plate used for fixation.

Polyethylene wear in total hip prostheses: the influence of direction of linear wear on volumetric wear determined from radiographic data.

PURPOSE: To develop a new mathematical model for calculating the volumetric wear of polyethylene cups from known values of the radius of the prosthesis head, the extent of linear wear and the direction of linear wear determined from standard antero-posterior radiographs. METHOD: A new mathematical model was developed. The results of this new mathematical model were compared with the results obtained using the standard, frequently used mathematical model, which takes into consideration only the radius of the prosthesis head and the extent of linear wear of the polyethylene cups. The results of both mathematical models were further compared with the results obtained by direct measurement of volumetric wear using the fluid displacement method. RESULTS: Comparison of the mathematical models shows that the average volumetric wear calculated using the new mathematical model is 8.5% smaller than the average volumetric wear determined by the fluid displacement method, while the average volumetric wear calculated by standard mathematical model is 17.5% higher. The results of the new mathematical model are, thus, notably less biased than those of the standard one. CONCLUSION: In calculating the volumetric wear from antero-posterior radiographs, not only the radius of the prosthesis head and the extent of the linear wear but also the direction of the latter has to be considered.

Influence of contact hip stress on the outcome of surgical treatment of hips affected by avascular necrosis.

INTRODUCTION: Biomechanical analysis is an important tool that could improve the treatment of a diseased hip. However, it is still unclear how the biomechanical status affects the clinical outcome of a certain disease. In this work we studied the long-term effect of contact hip stress on the clinical outcome of hips that were operated on by various intertrochanteric osteotomies due to avascular necrosis of the femoral head. The hypothesis being tested is that the hips with a more favourable postoperative distribution of contact hip stress have a better clinical outcome. MATERIALS AND METHODS: The study was performed on a population of 30 hips. For each hip, we determined the peak contact hip stress before the operation and immediately after the operation by using a recently developed method based on a three-dimensional mathematical model and the data from standard anteroposterior roentgenographs of both hips and pelvis. The hips were evaluated clinically 9-26 years after the operation and divided into a successful and an unsuccessful group. The average change of the peak stress due to the operation was calculated for each group, and the values were compared by t-test. RESULTS: In the successful group the operation caused an average decrease of the peak hip stress of about 10%, while in the unsuccessful group the operation caused an average increase of the peak hip stress of about 4%, the difference between the respective changes of the peak stress due to the operation being statistically significant ( p=0.001). CONCLUSION: Our results support the hypothesis that the hips with a more favourable postoperative distribution of contact hip stress have a better clinical outcome.

Intertrochanteric osteotomy for osteonecrosis of the femoral head.

We studied 32 hips (in 27 patients) treated by intertrochanteric osteotomy for osteonecrosis of the femoral head. Average follow-up was 17 (range 9-26) years. There were 22 men and 5 women with an average age of 39 (range 25-55) years. Eleven hips were classified as Ficat stage II, 19 as stage III and two as early stage IV. Nine hips showed collapse of the femoral head within 3 years after operation and in six hips collapse occurred after 3-8 years. In 13 hips slow progression with incipient signs of arthrosis was noted 8 years after surgery. Four hips with a moderate degree of necrosis at the time of surgery showed no radiological progression 9-26 years after operation. We recommend intertrochanteric osteotomy for patients with Ficat stage II and early stage III, provided that they still have a good range of motion in the hip.

Knee arthroscopy in children and adolescents.

We report a series of 77 skeletally immature patients (41 children aged < or = 13 years and 36 adolescents aged 14-16 years) who underwent knee arthroscopy. The purpose of the study was to assess the accuracy of clinical diagnosis and the value of arthroscopy. The correlation between clinical and arthroscopic diagnoses was analyzed in 54 patients. Arthroscopy confirmed the clinical diagnosis in 46.29% (25) of the patients. The accuracy of clinical diagnosis in patients aged 13 years and younger was 31.25%, whereas the accuracy in patients aged from 14 years to 16 years was 68.18%. Paediatric knee arthroscopy is a safe procedure that significantly improves the accuracy of clinical diagnosis, allows the definitive treatment of a variety of conditions and often prevents an unnecessary arthrotomy.

The effect of electrostimulation and high load exercises in patients with patellofemoral joint dysfunction. A preliminary report.

Traditional conservative treatment for patellar disorders is successful in about 80 percents of cases. We introduced two new conservative treatment protocols for patellar pathology in order to further improve the success rate. The first protocol consisted of high load/low repetition quadriceps femoris training (10 patients) while the second enclosed selective electrostimulation of vastus medialis muscle (7 patients). Results were evaluated clinically and neurophysiologically. High load/low repetition training resulted in significant increase of maximal voluntary contraction of quadriceps muscle (P < 0.001). Significant gain of Activity (P = 0.017) and Kujala scores (P = 0.07) was observed in group with high load/low repetition quadriceps training compared to patients with electrostimulation. There was no significant change in neurophysiological or clinical status between the beginning and the end of treatment with electrostimulation. Our results indicate that high load/low repetition quadriceps femoris training poses an important alternative to traditional conservative treatment protocol for patellar disorders.

Operative treatment of destructive spondyloarthropathy of the lumbar spine in a patient on chronic dialysis.

We present a patient with end-stage renal disease treated by chronic dialysis, in whom progressive destructive spondyloarthropathy of the lumbar spine was successfully managed by fusion with internal fixation, resulting in relief of pain and restoration of activity.

Extensive metallosis and necrosis in failed prostheses with cemented titanium-alloy stems and ceramic heads.

We describe three prostheses with cemented titanium-alloy stems and Al2O3 ceramic femoral heads which had to be revised after a mean period of implantation of 78 months. In each case, the neck of the prosthesis had been so severely worn that the profile was elliptical rather than circular. There was severe metallosis of the periprosthetic tissues. Metal particles isolated from the tissues were approximately one nanometre in size and the ratios of titanium, aluminium and vanadium in the particles were the same as in the original alloy. Histologically, the high concentration of metal particles masked the presence of high-density polyethylene (HDP) debris, but again particles about one nanometre in size were isolated from the tissues. The severe necrobiosis and necrosis noted were consistent with other reports of the presence of extensive wear particles in periprosthetic tissues. Wear is presumed to have occurred as a result of mismatch between the shape or size of the taper cone and the femoral head, or to changes in the geometry of loading due to migration of the cup. To facilitate early intervention, patients with this design of prosthesis should be monitored radiologically.

Femoral head necrosis treated with vascularized iliac crest graft.

We reviewed 24 hips with avascular necrosis of the femoral head in 24 patients treated with vascularized iliac bone grafts 12 years after operation. In 7 patients the necrosis was classified as Ficat Stage II and in 17 patients as Stage III. Eight patients showed poor results. In 6 hips with fair results, moderate progression of the necrosis was noted at 3 to 8 years postoperatively. In 5 hips showing good results, slow progression with incipient signs of arthrosis were noted 8 years after surgery. In the remaining 5 patients with excellent results, no evidence of progression was noted 9 to 14 years postoperatively. The method described is recommended for treatment in the Ficat Stage II and early Stage III, when necrosis does not yet involve the complete femoral head.

[Anterior cruciate ligament function: a non-invasive quantitative technique]. / Laximétrie du ligament croisé antérieur: une technique quantitative non invasive.

PURPOSE OF THE STUDY: The purpose of the study was to develop a new non-invasive and quantitative method for evaluation of the anterior cruciate ligament function. PATIENTS AND METHODS: The new method was tested in 24 asymptomatic subjects and in 58 patients (39 males and 19 females) with arthroscopically proven unilateral rupture of the anterior cruciate ligament. Anterior displacement of the tibia with the knee in 20 degrees flexion was achieved by using a redesigned device, constructed originally for stress-radiography, and detected by a 3-D optical motion analysis system. RESULTS: In the normal group, the average difference (d) in anterior displacement of the tibia between the left and the right side under a displacement force of 250N was 0.56 mm (range 0.1 mm to 1.9 mm) or 17 p. 100 (range 2 p. 100 to 64 p. 100), while in patients the average difference (d) in anterior displacement of the tibia between the injured and uninjured side under a displacement force of 250N was 4.02 mm (range 0.6 mm to 9.4 mm) or 133.6 p; 100 (range 26 p. 100 to 451 p. 100). By the criteria for false negative results, i.e. the maximum value of the parameter d in normal subjects (1.9 mm and 64 p. 100), 10 p. 100 of the patients (6 patients) fell into the normal group. According to the criteria of false positive results, i.e. the minimum value of the parameter d in patients (0.6 mm and 26 p. 100), 17 p. 100 of the normal subjects (4 normal subjects) fell into the group of patients. The achieved level of differentiation is in the similar range as the most frequently used present methods. DISCUSSION: The main advantage of the newly developed noninvasive optical measurement technique is that the direction of force and the amplitude and site of application are accurately defined and documented, and that dislocation movement of the tibia towards the femur during the application of a growing force is continuously monitored with the 3-D optical system and that it allows for several consecutive assessments based on statistical data.

Increased muscle stiffness after anterior cruciate ligament reconstruction--memory on injury?

Residual impairment of knee function was tested in 25 patients 6 to 12 months after successful unilateral reconstruction of the anterior cruciate ligament. The control group comprised 25 healthy individuals. Jumping onto one foot from a height of 20 cm was taken as a prototype of similar everyday activities. We measured maximum flexion of the knee during the landing phase of the jump, and the degree of knee flexion at the time of maximum deceleration of the knee against gravity during jumping using the three-dimensional optical motion analysis system-ELITE. In the group of patients, measured parametres were significantly smaller on the operated side than on the unaffected side. These two measured values were significantly smaller on both legs in group of patients as compared to the values in the control group. The results of our study indicate that functional disturbance persisted for 6 to 12 months after anterior cruciate reconstruction. This may be due to the changed muscle activation pattern of the knee causing increased stiffness of knee muscles. It seems that re-programming of the central nervous system occurred in order to protect the injured lower extremities from another injury.

Surgical treatment of clubfoot: the significance of talocalcaneonavicular malposition correction.

In a retrospective study on the surgical management of clubfoot based on clinical and radiographic assessments, 171 feet in 137 patients were reviewed. The surgical procedure was selected according to the degree of the deformity. The more severe cases (group A, 75 feet) were surgically treated according to Turco's one-stage posteromedial release, whereas the milder degrees of deformity (group B, 96 feet) were corrected by elongation of the Achilles tendon with posterior capsulotomy. The mean age of the patients at surgery was 12.5 months in group A and 5.2 months in group B. The mean follow-up time for both groups was 12.2 years. At follow-up, 24 feet (41%) in group A and 52 feet (68%) in group B required repeat surgery. In group A the results were good in 51 feet (68%), fair in 15 (20%), and poor in 9 (12%). In group B, good results were obtained in 44 feet (45%), barely satisfactory results in 25 (27%), and poor results in 27 (28%). It is suggested that the accurate correction of talocalcaneonavicular and calcaneocuboid malposition is a prerequisite for successful surgical treatment of clubfoot. There was a tendency for a better result in group A when the patients were surgically treated between 6 and 12 months of age.

[The septic knee - arthroscopic treatment.]. / Kniegelenkempyem - Arthroskopische Behandlung.

Arthroscopic irrigation has proved very effective in the treatment of the septic knee, provided that it is begun at the earliest possible time. We obtained very good results in 25 out of 27 cases treated by radical irrigation in the first three days after the start of infection. Cases where the infection had been present for more than six days were managed by synovectomy. Surgical therapy must be accompanied by intensive CPM treatment, combined with isometric exercises for the quadriceps muscle in order to achieve a good functional outcome. Key words: septic knee, arthroscopic irrigation.

Surgical treatment of spondylolysis and spondylolisthesis with a hook screw.

Seventeen patients with spondylolysis and minimal spondylolisthesis were treated with a Morscher hook screw and bone grafting. At follow up, 82% had no symptoms and radiographs confirmed fusion of the isthmic defect. One patient had occasional pain, and two had an unsatisfactory result. They were both over 25 years of age and had a moderate displacement of 3-4 mm.

Calf-tendon jerks are altered in congenital equinovarus deformity.

Stretch reflexes of posterior tibial (PT) and triceps surae (TS) muscles were studied electrophysiologically in 27 children with unoperated unilateral congenital equinovarus deformity, in an attempt to evaluate changes in tone of the leg muscles as a possible pathogenetic factor. Significantly reduced latency of the PT responses on the affected side was recorded in a majority of patients. In most patients the amplitudes of the PT responses were asymmetrical; however, lateralization was inconsistent. The TS responses were asymmetrical in a smaller proportion of the patients, though still significantly different from the controls. The findings suggest an asymmetrical increase in excitability level of the PT motoneuron pool on the affected side.

Treatment of resistant idiopathic pes equinovarus: ten-year experience.

Fifty cases of clubfeet (38 children) were evaluated 10 years after surgery. Turco's method was used in 22 cases, while 24 were managed with Achilles tendon lengthening and dorsal capsulotomy. After Turco's operation, good results were achieved in 69% and the deformity recurred in 31%. In the second group, the success rate was 63%. Recurrences are due to insufficient reduction of the talocalcaneonavicular joint. The authors conclude that Achilles tendon lengthening and posterior capsulotomy should be carried out by age 4 months. If by the age of 1 year the foot has not yet assumed its normal position, complete operative reduction is recommended. Preliminary results of histochemical studies of the peroneal muscles are presented.