Bioabsorbable fixation in orthopaedic surgery and traumatology.

Bioabsorbable internal fixation devices were introduced clinically in the treatment of fractures and osteotomies of the extremities at the Department of Orthopaedics and Traumatology, Helsinki University, in 1984. Since November 5, 1984, a total of 3200 patients were managed using bone or ligament fixation devices made of self-reinforced (matrix and fibres of the same polymer) bioabsorbable alpha-hydroxy polyesters. The devices used included cylindrical rods, screws, tacks, plugs, arrows, and wires. The most common indication for the use of bioabsorbable implants was the displaced malleolar fracture of the ankle. Transphyseal fixation with small-diameter, mainly polyglycolide pins was used in children. The postoperative clinical course was uneventful in more than 90% of the patients. The complications included bacterial wound infection in 4% and failure of fixation in 4%. In one-fifth of the latter cases, however, re-operation was not necessary. The occurrence of non-infectious foreign-body reactions two to three months postoperatively has been observed in 2% of the patients operated in the last few years with polyglycolide implants but none of the patients managed with polylactide implants. This inflammatory tissue response often required aspiration with a needle but did not influence the functional or radiologic result of the treatment. Owing to the biodegradability of these internal fixation devices, implant removal procedures were avoided. This results in financial benefits and psychological advantages. Bioabsorbable implants can also be used in open fractures and infection operations.

Macrophage-colony stimulating factor (M-CSF) is increased in the synovial-like membrane of the periprosthetic tissues in the aseptic loosening of total hip replacement (THR).

The aim of the study was to assess the eventual presence, cellular localization and extent of expression of the osteoclast activating cytokine M-CSF (CSF-1) in the periprosthetic tissues around loose total hip replacement (THR). Synovial-like membrane was obtained from the implant-to-bone interface and pseudocapsule from ten total hip revisions performed for aseptic loosening and compared to ten hip synovial tissue samples obtained from ten patients who had primary THR for osteoarthritis. Avidin-biotinperoxidase complex (ABC) and alkaline phosphatase-anti-alkaline phosphatase (APAAP) methods were used for staining and VIDAS image analysis for quantification. M-CSF was mainly produced by macrophages, which often contained wear particles, but also by some fibroblasts and vascular endothelial cells. The number of cells containing (per one mm2 tissue) clearly increased in the interface (1585 +/- 212; p < 0.01) and pseudocapsular (1456 +/- 248; p < 0.01) tissue compared to synovial tissue (543 +/- 118). The present findings suggest, that inflammatory foreign-body type of response enhances expression of M-CSF in cases of aseptic loosening of THR. M-CSF produced in the synovial-like membrane in the implant-bone interface may contribute to activation of osteoclasts in periprosthetic bone and thus to loosening.

Self-reinforced absorbable screws in the fixation of displaced ankle fractures: a prospective clinical study of 152 patients.

The series consisted of 152 patients with ankle fractures treated between May 1987 and August 1989 using absorbable screws of self-reinforced polyglycolide 3.4 mm in inner diameter and 25-70 mm in length. The mean follow-up time was 2 years, 5 months (range, 1 year, 7 months-3 years, 10 months). After open reduction, a channel was drilled through the fracture surfaces and the fragments were fixed with one absorbable screw or screws. A plaster cast was used postoperatively. At 1-year follow-up observation, the radiographical result was anatomical in 93.3% of 104 patients with unimalleolar and bimalleolar ankle fractures (Weber A or B) and in 80.5% of 41 severe ankle fractures. Seven patients were unavailable for follow-up observation. Two reoperations were performed because of primary or secondary failure of fixation. In all unimalleolar and bimalleolar fractures and in 95.1% of severe ankle fractures the functional recovery score was at least satisfactory. Sinus formation as a sign of tissue reaction was observed in 10 patients 2-6 months postoperatively, but this did not influence the healing of the fracture or the functional recovery. This report is the first extensive publication on the clinical use of absorbable screws.

Arthrodesis of the wrist with bioabsorbable fixation in patients with rheumatoid arthritis.

Twenty-four wrist arthrodeses were performed on 18 patients with rheumatoid arthritis using a bioabsorbable self-reinforced poly-L-lactide rod as the fixation device. There was one nonunion which required a re-operation and two nonunions which did not need further treatment. The position of the arthrodesis was ulnar deviation and extension in most patients, and there was high patient satisfaction with 21 of the 24 wrists and satisfactory pain relief in 22 of the 24 wrists. This method for fusing the wrist in patients with rheumatoid arthritis appears reliable and simple to perform.

Reinsertion of the ruptured ulnar collateral ligament of the metacarpophalangeal joint with an absorbable self-reinforced polylactide tack.

70 patients with total avulsion or rupture of the ulnar collateral ligament of the first metacarpophalangeal joint were treated surgically, using an absorbable self-reinforced poly-L-lactide mini-tack placed through the ligament and a channel in the base of the proximal phalanx. The device stabilized the joint immediately, and 69 ligaments remained stable at 6 months. The subjective result was good or satisfactory in 66 of the cases. One case needed further surgery for pain in the scar and another developed local infection 9 months post-operatively. On the basis of these findings, the new absorbable fixation method seems to be a suitable method for clinical use.

Regeneration of defects in articular cartilage with callus and cortical bone grafts. An experimental study.

Cartilage regeneration was studied in an experiment in rats. A standardised full-thickness articular cartilage defect was created and autogenous 12-day-old callus or cortical bone graft was transplanted into it, or the defect was left empty. The follow up periods were three, six, 12, and 24 weeks, and each subgroup consisted of five animals. A total of 60 animals were operated on. From six weeks onwards hyaline-like cartilaginous tissue had started to develop at the edges of the defect in all three groups. In the middle section of the hole, however, the picture was different; at 24 weeks none of the specimens in the defect group, two of the five in the callus graft group, and all five in the bone graft group had developed full-thickness, hyaline-like cartilaginous regeneration. The hyaline-like cartilaginous tissue in the medical segment was hypocellular when analysed by histomorphometry. On scanning electron microscopy the surface of the reparative tissue looked fibrillated in all specimens from the three groups.

Follow-up study of synovectomies of the knee joint in patients suffering from rheumatoid arthritis.

Synovectomies of the knee joint that were performed during the years 1960-65 at the Rheumatism Foundation Hospital because of rheumatoid arthritis have been re-examined after the lapse of 9.5 years in 156 patients and 202 knee joints and 110 non-operated knee joints of the same patients. Track of motion was helped both in synovectomized and in control knees. Deficiency of extension decreased only in the synovectomized knees; track of motion of the knee was improved by the operation. Swelling and pain appeared less often in operated than in control knees. The patient's own assessment of the operating results was good in 71% and poor in 12% of the cases. Radiological deterioration continued during the follow-up period both in the operated and in the control knees, though it was more severe in the latter. There is a distinct negative correlation between severity of disease and the patients's ability to work. Within the limits of this survey it is not possible to prove that synovectomy halts the radiological destruction of the knee joint; it is mainly a question of a measure that retards the rate of deterioration. One of the chief advantages of synovectomy of the knee is that it helps the patient to live a normal life and makes it possible for him to participate in working life.

Synovectomy of the wrist in rheumatoid arthritis and related diseases. A follow-up study of 97 consecutive cases.

Synovectomy of the wrist was done on 77 patients (97 wrists) during 1968-1981. The age of the patients at the time of operation ranged from 18 to 77 years, mean 44.9 yrs. Clinical and radiological follow-up examinations (90 wrists) or follow-up evaluation by questionnaire (7 wrists) were made by the authors in 1982. The mean length of the follow-up period was 8.5 years. Clinical symptoms of pain, swelling, restricted motion, instability and deformity of the wrist joint were evaluated and graded according to a special score. Radiological changes due to rheumatoid arthritis and osteoarthrosis were graded and analysed. Eight wrists were arthrodesed during the follow-up. Among the remaining wrists (89 cases) pain was absent or almost absent in 39%, was less than before the operation in 49% and was unchanged or worse in 12% of cases. The respective percentages for the presence of swelling were 47%, 36%, and 17%. The range of dorsiflexion was between 0 and 70 degrees, with an average of 27.9 degrees. The range of volar flexion was between 0 and 75 degrees, the mean being 28.2 degrees. The average ulnar and radial side motions were 12.9 degrees and 5.4 degrees, respectively. The radiological grading of RA remained about the same in 10 wrists and did not improve in a single wrist. In the other wrists the X-ray changes progressed. The results (patient's opinion) were subjectively good in 53%, fair in 32%, and poor in 15%.(ABSTRACT TRUNCATED AT 250 WORDS)

Arthrodesis in rheumatoid arthritis using absorbable screws and rods.

In this series absorbable fixation devices (screws and rods) made of self-reinforced poly-L-lactide (SR-PLLA) were used to stabilize arthrodesis in rheumatoid arthritis. These fixation devices have been used mainly in the fracture treatment or in the fixation of osteochondral lesions or osteotomies in hallux valgus operations. In arthrodesis of post-traumatic arthritis these devices have been used successfully. Fifty-three arthrodeses (18 in the wrist, 18 in the hand, 6 talocrural joint and 11 subtalar-calcaneocuboid-talonavicular joint) were performed for 47 patients using absorbable screws and rods between 1989 and 1994. Overall results in every group were good. There were 3 superficial infections and 2 nonunions (both talocrural arthrodesis). According to this study it seems that absorbable screws and rods are interesting alternative fixation devices in arthrodesis in rheumatoid arthritis.

Social factors associated with lumbosacral fusion.

The relationship between the end results of operative fusion of the lumbosacral spine and social and occupational factors was investigated. The series consisted of 133 patients operated on in 1968--75. The social background of 116 patients was clarified by the use of questionnaires in connection with the follow-up examination period 4.8 years postoperatively, on an average. The data were classified as far as possible according to the same principles as were used in the Finnish census of 1970. This made it possible to compare the present series with the total population. The average educational level and social status were found to be lower in this series, divorcees were more frequent, and the households were larger than in the population at large. Moreover, the age groups 30--39 and 40--49 years were overrepresented. The end-results, postoperative working capacity in particular, correlated to a statistically significant extent with educational level, the kind of pre-operative work, occupational group, social group, number of children and size of the place of residence. It is concluded that social factors ought to be considered when selecting patients for lumbosacral fusion, even if an operation appears to be warranted on medical grounds alone. In addition, the importance of comprehensive rehabilitation for patients with low back pain is emphasized.

Cost-benefit analysis of synovectomy of the knee.

The subject of this study was the cost-benefit ratio of synovectomy of the knee. Synovectomy of the knee is the most common operation at the Rheumatism Foundation Hospital, Heinola. In 1973 it accounted for 8.8% of all orthopedic operations performed. The survey material comprises 225 synovectomies of the knee performed on 208 patients. The age and sex distribution of the patients has been obtained from the material for 1973. The second series consists of 181 patients who underwent synovectomy of the knee during the period 1960-65 and who were re-examined in 1970-75. From the said material, data have been obtained on the postoperative professional working activity of patients and on the number of other hospital treatments given to these patients. These coefficients have been transferred to relate to the year 1973. Of those patients who underwent an operation in 1973, 70.9% were women and 29.1% were men. Their average age at the time of operation was 41 years. Their working age was 24 years on average. The operation and related total patient treatment inclusive of other orthopedic operations constitute a vital measure of the preservation of the patient's working ability. Cost-benefit analysis was the research method employed. The year 1973 was chosen as the period for investigagion. Costs due to synovectomy of the knee amounted in 1973 to about 1.6 million marks. Total costs averaged 7000 marks per operation. The greatest potential benefits accruing from synovectomies of the knee prove to be multiple as compared with with costs. Reckoned according to different rates of interest (6% and 9%) maximum benefits are about 8.2-9.8 million marks. As compared with costs, benefits are approx. 5.2-6.2 times as great. Maximum net benefits per one operation are about 43770 marks. Operations can be regarded as economically justifiable even in those cases where it is possible to preserve working ability for a period of 10 years for 10% of the patients. Furthermore, the effect of non-quantified benefits should also be considered.

Rupture of the patellar tendon.

Five patients with closed rupture of the patellar tendon, treated without delay with end-to-end suture, were reviewed. The suture line was reinforced with a steel wire in only one case. The follow-up time was at least three years in all patients. No reruptures were seen. The functional result was considered good in three and satisfactory in two patients.

Internal fixation of forearm fractures in children.

Fourteen children with severely displaced diaphyseal fractures of both bones of the forearm treated with open reduction and internal fixation were reviewed; these operations represented 9 per cent of all the diaphyseal forearm fractures in children during a 9-year period. The mean age of the patients at the time of the injury was 12 (7-14) years; they were reexamined 8 (5-11) years later, all after cessation of growth. At follow-up, limited prosupination, observed in 8 patients, was associated with a fracture of the proximal third of the forearm; limited motion of the radiocarpal joint, in 2 patients, was associated with shortening of the ulna. Only 4 patients complained of pain or were aware of restricted motion, and the average function was good. Open reduction and internal fixation is indicated in displaced fractures of the forearm even in children.

Outcome of operative treatment in fresh lateral clavicular fracture.

23 fresh type II (Neer 1963) lateral clavicular fractures, were treated operatively. In 19 cases fixation was done with two Kirschner wires, in four cases plating was performed. The coracoclavicular ligament was left unsutured. The average follow-up period was 4.5 (1-12) years. In 22 cases out of 23 the subjective outcome was good or satisfactory. 22 fractures united and there were few complications.

Posterior approach for total hip arthroplasty. A study of postoperative course, early results and early complications in 131 cases.

We report a consecutive series of 131 total hip arthroplasties using a prosthesis of Brunswik type and a posterior approach to the hip. Special attention is paid to technical details, postoperative course and early complications. The results are compared with those in published studies in which the lateral transtrochanteric approach has been used. Total hip replacement was performed by a team of four persons. This led to a marked decrease in the average operating time (60 minutes). The amount of blood transfused during and after the operation averaged 761 g. The postoperative course was complicated by one wound infection (0.8%). The immediate results regarding pain and walking capacity were good in 83% of the cases. The use of the posterior approach and a highly trained operating team reduced the time required for the operation, the blood loss and the frequency of postoperative complications, and caused less morbidity in the arthritic patients.

Rupture of the quadriceps tendon.

Twelve patients operated for fresh rupture of the quadriceps tendon were re-examined after 5 (2-11) years. The tendon was sutured end-to-end or to the patella. The result was good in seven cases, fair in four and poor in one case of re-rupture, left unrepaired.

Fracture of the tibial tuberosity in adolescents.

Fracture of the tibial tuberosity is an uncommon injury and rarely occurs after closure of the proximal tibial epiphysis. Three cases of tibial tuberosity fracture over a period of 11 years were treated by open reduction, internal fixation, and immobilization for 6 weeks in plaster of Paris (1970-1980). The postoperative follow-up times were 5, 6, and 7 years. No subsequent deformities were detected. Two patients had secondary posttraumatic patella infera without any symptoms. All patients returned to normal activity. The results demonstrated that this injury in the adolescent knee heals without deformity of functional loss when adequate reduction and fixation of the fracture fragments have been achieved.

Comparison of intra- and extraosseally placed self-reinforced poly-L-lactide plates in the fixation of distal femoral osteotomies in rabbits.

BACKGROUND AND AIMS: We have developed the intraosseal plating method with self-reinforced poly-L-lactide (SR-PLLA) plates. In the present study for comparison, the other plates were implanted on both sides of the bone because two plates separated by a 2-5 mm bony bridge in the intraosseal fixation proved successful. The two fixation methods may have different effects on the formation of new bone, and we measured this event histomorphometrically. MATERIALS AND METHODS: Osteotomies of the distal femora in 20 adults rabbits were fixed intraosseally with two SR-PLLA plates and four titanium screws and in 20 adult rabbits with identical plates fixed on both sides of the bone with four metallic screws. The follow-up times were three, six, 12, and 24 weeks. The amount of trabecular bone at the osteotomy site was evaluated histomorphometrically. RESULTS: In both groups and after each follow-up time greater trabecular bone percentage values were noticed on the operated sides. The amount of bone was greatest near the plates and particularly strong between the plates in intraosseal plating. CONCLUSIONS: Intraosseally implanted SR-PLLA plates do not seem to diminish the amount of trabecular bone when compared to similar plates on the bone.

Comparison of costs in ankle fractures treated with absorbable or metallic fixation devices.

The economic costs of ankle fractures treated operatively with self-reinforced polyglycolide acid (SR-PGA) screws, with self-reinforced poly-L-lactide acid (SR-PLLA) screws or with metallic implants was determined. All patients were divided into three groups according to the fixation material used. Open and otherwise complicated fractures were excluded. The total expense of operations in each group was taken into account. The average total cost of an ankle fracture fixed with SR-PGA screws was Pounds 3503. In the SR-PLLA group it was Pounds 3906, and in the metallic group it was Pounds 4514. Total expenses were Pounds 1011 higher in the metallic group than in the SR-PGA group, and consequently, expenses in the metallic group were Pounds 608 higher than in the SR-PLLA group. According to this study, it seems that absorbable fixation devices are more economical than metallic implants in operative treatment of ankle fractures though as part of the differences in total expense in this series is due to the age of the patients and other dissimilarities between these groups, the results have to be interpreted carefully.