Interpositional Arthroplasty of the First Metatarsophalangeal Joint with Bioresorbable Pldla Implant in the Treatment of Hallux Rigidus and Arthritic Hallux Valgus: A 9-Year Case Series Follow-Up.

BACKGROUND AND AIMS: The interpositional arthroplasty was developed to retain foot function and to relieve pain due to the arthritis of the first metatarsophalangeal joint. The bioabsorbable poly-L-D-lactic acid RegJoint® interpositional implant provides temporary support to the joint, and the implant is subsequently replaced by the patient's own tissue. In this study, we retrospectively examined the results of the poly-L-D-lactic acid interpositional arthroplasty in a 9-year follow-up study among patients with hallux valgus with end-stage arthrosis or hallux rigidus. MATERIAL AND METHODS: Eighteen patients and 21 joints underwent interpositional arthroplasty using the poly-L-D-lactic acid implant between February 1997 and October 2002 at Tampere University Hospital. Of these, 15 (83.3%) (21 joints) patients were compliant with clinical examination and radiographic examination in long-term (average 9.4 years) follow-up. The mean age of the patients was 48.3 (from 28 to 67) years at the time of the operation. Six patients underwent the operation due to arthritic hallux valgus and nine patients due to hallux rigidus. RESULTS: The mean Ankle Society Hallux Metatarsophalangeal-Interphalangeal Scale and visual analogue scale (VAS) for pain scores improved after the operation in all patients. The decrease of pain (visual analogue scale) after the operation was statistically significant (77.5 vs 10.0; p < 0.001). Postoperative complications were observed in 3 (14.3%) joints of two hallux rigidus patients. For these patients, surgery had only temporarily relieved the pain, and they underwent reoperation with arthrodesis. CONCLUSION: In conclusion, interpositional arthroplasty using a poly-L-D-lactic acid implant yielded good results. This study indicates that the poly-L-D-lactic acid interpositional implant may be a good alternative for arthrodesis for treatment of end-stage degeneration of the first metatarsophalangeal joint.

Can orthotic insoles prevent lower limb overuse injuries? A randomized-controlled trial of 228 subjects.

Lower limb overuse injuries are common among people who are exposed to physical stress. Orthotic shoe insoles are widely used to prevent lower limb overuse injuries. Here, we conducted a randomized-controlled study to examine whether the use of orthotic insoles prevents lower limb overuse injuries. Participants (n=228) were randomly assigned to use (n=73) or not to use (n=147) orthotic insoles. The insoles were molded to the shape of the foot to provide support during physical activity. The main outcome measure in the present study was the physician-diagnosed lower limb overuse injury. Thirty-four (46.6%) subjects in the insole group were diagnosed with a lower limb overuse injury compared with 56 (38.1%) in the control group (P=0.29) during the 6-month study period. When body mass index and the results of a 12-min running test and muscle strength were adjusted in a Cox's regression model, the hazard ratio for lower limb overuse injury in the insole group was 1.3 (95% confidence intervals: 0.8-2.1) compared with the control group. Use of orthotic insoles was not associated with a decrease in lower limb overuse injuries. Our findings suggest that routine use of orthotic insoles does not prevent physical-stress-related lower limb injuries in healthy young male adults.

Functional treatment of closed humeral shaft fractures.

We treated 93 consecutive patients, average age 53 (16-90) years, with closed humeral shaft fractures applying a functional brace immediately after injury. Seventy-two (77%) fractures healed without problems. There were significantly more consolidation problems in fractures in the proximal third (46% consolidated) compared to those at the middle (81% consolidated) and distal third (86% consolidated) of the shaft. Logistic regression analysis revealed the only predictive factor in respect to successful brace treatment was fracture location. No significant difference was found in respect to healing between different AO-type fractures.

Charcot arthropathy of the diabetic foot. Current concepts and review of 36 cases.

BACKGROUND AND AIMS: The incidence of diabetic Charcot neuroarthropathy has increased. The purpose here was to study the current diagnostics and treatment of the Charcot foot. MATERIALS AND METHODS: During a time period from 1994 to 2000, a total of 36 feet were diagnosed as cases of diabetic Charcot neuroarthropathies. A retrospective analysis of patient records and radiographs was undertaken. A review of the recent literature is presented. RESULTS: 29 cases were diagnosed in the dissolution stage, 2 in coalascence, and 5 in the resolution stage. The diagnostic delay averaged 29 weeks. Treatment with cast immobilisation ranged from 4 to 37 weeks (mean 11 weeks). A total of 14 surgical procedures were carried out on 10 patients: six exostectomies, four midfoot arthrodeses, one triple arthrodesis, one tibiocalcaneal arthrodesis and two below-knee amputations. A radiological fusion was achieved in two thirds of the attempted arthrodeses. CONCLUSIONS: A physician should always consider the Charcot neuroarthropathy when a diabetic patient has an inflamed foot. In the absence of fever, elevated CRP or ESR, infection is a highly unlikely diagnosis, and a Charcot process should primarily be considered. The initial treatment of an inflamed Charcot foot consists in sufficiently long non-weightbearing with a cast, which should start immediately after the diagnosis. The prerequisites of successful reconstructive surgery are correct timing, adequate fixation and a long postoperative non-weightbearing period. In the resolution stage most Charcot foot patients need custom-molded footwear.

Thompson hemiarthroplasty is superior to Ullevaal screws in treating displaced femoral neck fractures in patients over 75 years. A prospective randomized study with two-year follow-up.

BACKGROUND AND AIMS: The Finnish orthopaedic tradition has preferred hemiarthroplasty to internal fixation in femoral neck fracture treatment, while in Sweden internal fixation has been the method of choice. We decided to study whether internal fixation would prove superior to hemiarthroplasty even in displaced femoral neck fractures in patients over 75 years old. MATERIAL AND METHODS: We randomized 32 displaced femoral neck fractures in patients over 75 years old to receive internal fixation or hemiarthroplasty. RESULTS: Fifteen (47%) patients died within two years. Seven of 16 (44%) patients in the internal fixation group were reoperated, none in the hemiarthroplasty group (p = 0.007). Seven of the complications in the internal fixation group developed during the first year and it would have been unethical to continue the study. CONCLUSIONS: We conclude that displaced femoral neck fractures in patients over 75 years should be treated by arthroplasty.

The femoral canal fill of two different cementless stem designs. The accuracy of radiographs compared to computed tomographic scanning.

In 19 cadaver femora we compared the fill of two types of femoral stems (plastic replica) using computed tomographic (CT) scan with a border detecting computer program and conventional radiographs. In the metaphyseal area the fill of the two types was surprisingly similar. In the diaphysis the straight stem filled significantly more than the proximally anatomic and distally over-reamed stem. Using conventional radiographs the fill measures were from 1.2 to 2.1 times higher than the values of CT scan, depending on the method of calculation. When both anteroposterior and lateral views were used, the fill as measured by radiographs correlated well with the fill as measured using CT scan. When conventional radiographs are used for evaluation of the canal fill, the calculation based on hypothetical rectangular areas at each level seemed to provide the most accurate results.

Alarming wear of the first-generation polyethylene liner of the cementless porous-coated Biomet Universal cup: 107 hips followed for mean 6 years.

Wear of the socket liner and resulting osteolysis are the major causes of failure in cementless hip arthroplasties. We report alarming wear of the first-generation polyethylene liner of the cementless porous-coated Biomet Universal cup. Radiographs of 107 primary hip arthroplasties were analyzed retrospectively. The mean follow-up time was 74 (47-91) months. The linear wear of the polyethylene liners was assessed using a modification of the Livermore method. The median linear wear was 1.0 (0-6.2) and the median linear wear rate was 0.17 mm/year. There was a statistically significant difference between the 28 mm and 32 mm femoral head groups both in the volumetric wear and in the volumetric wear rate. The median linear wear was 0.28 mm/year and 0.14 mm/year for the 32 mm and 28 mm heads, respectively. So far, 14 revisions have been performed or have been scheduled because of excessive wear of the polyethylene liner. In regression analysis, the factors related to the wear rate were the 32 mm size of the femoral head and screw fixation of acetabular shell. We found that the cases with calcar rounding were associated with significantly greater wear. Possible reasons for increased wear of the Hexloc liner may be the cylindrical design, thin polyethylene, and poor quality of the polyethylene. Regular clinical and radiographic follow-ups are recommended especially for hips with 32 mm femoral heads or with screw fixation. If progressive wear of the liner is observed, revision must be considered.

The effects of cementless femoral stem shape and proximal surface texture on 'fit-and-fill' characteristics and on bone remodeling.

We measured the post-operative radiological "fit and fill" of two different femoral stem designs, one with a straight proximally porous-coated (Bi-Metric, n=50) and the other with a proximally anatomic, hydroxyapatite-coated and distally over-reamed stem (ABG, n=26). A comparison was then made between the clinical and radiological 5-year follow-up data of these two series and also of the bone remodeling changes around the stems. The observed differences in "fit and fill" parameters in the metaphyseal region were minute. However, in the diaphyseal bone the straight stem had substantially more cortical contact. The clinical results were excellent for both groups. Subsidence (>2 mm) was more frequent with the anatomical ABG stems, although the ABG stems had better bone ingrowth in the lower metaphyseal area. The present results indicate that the anatomical design may improve the fit and fill of a femoral stem in the metaphysis. On the other hand, a looser fill of the diaphyseal bone made the stems of this type more susceptible to subsidence. The straight stem with tight diaphyseal fit showed excellent stability, but the good bone ingrowth and remodeling around the distal part of the stem indicates stress transfer through this region and increased stress shielding of the proximal metaphyseal femur.

Diversity of proximal femoral medullary canal.

To analyze the endosteal dimensions of the proximal femoral medullary canal, we studied 50 cadaver femora using computed tomography and a border detection method from 20 mm above the lesser trochanter, the osteotomy level, down to the isthmus. We documented the presence of a dense calcar septum in 96% of femora studied. In addition to mediolateral, anteroposterior, and neck-oriented dimensions, we calculated canal flare indices (CFIs) between the osteotomy level and the isthmus and metaphyseal canal flare indices (MCFIs) between the osteotomy level and the level 20 mm below the lesser trochanter midpoint to describe the shape of the endosteal cavity. With respect to the canal opening, the anteroposterior and mediolateral planes parallelled each other over the entire region as indicated by the high correlation (r = .7, P < .001) between the CFIs in these directions. The prediction of one dimension from another was unreliable in the metaphyseal region, where bone ingrowth is supposed to occur in a femoral prosthesis. The MCFI seemed to be the best parameter to distinguish the various types of proximal femoral canal shapes. We have described the variability of the proximal femoral endosteal dimensions in detail and find that the wide variation in the shape and size of the proximal femoral medullary canal means that it is almost impossible to achieve 100% cortical contact with the stem, especially in the metaphysis.

Image processing for femoral endosteal anatomy detection: description and testing of a computed tomography based program.

A computed tomography (CT)-based image processing computer program was developed for three-dimensional (3D) femoral endosteal cavity shape modelling. For the examinations 50 cadaver femora were used. In the CT imaging 30 axial slices were taken above and below the lesser trochanter area from each femur. Different image analysis methods were used for femoral cavity detection depending on the structure of the processed slice. In the femoral shaft area simple thresholding methods succeeded, but in the problem areas of the metaphyseal femur edge, detection operators and local thresholding were required. In contour tracking several criteria were used to check the validity of the border pixels. The results were saved as four output data files: (i) a file for the longest anteroposterior (ap), mediolateral (ml) and oblique diameters computed by a Euclidian method, (ii) and (iii) files for 2D and 3D data respectively, and (iv) a file for centre points of each slice. Finally, testing of the results and dimensions obtained from the image analysis were carried out manually by sawing the femora into 10 stipulated horizontal slices. The ap and ml dimensions were measured with a caliper ruler. The CT-based image processing yielded a peak distribution of dimensions with a negative difference to those obtained in manual measurements. The mean difference between the image processing and the manual measurements was 1.1 mm (+/-0.7 mm, +/-1 SD). The difference was highest in the proximal slices of the femora of group I (with lowest cortical thickness), i.e. 1.3 mm (+/-0.8 mm) and lowest in the distal slices of the femora from group III (with highest cortical thickness), i.e. 0.9 mm (+/-0.6 mm). The results are acceptable for further use of the program to study endosteal anatomy for individual femoral component selection and designing basis.