Distal radius osteotomy in the elderly patient using angular stable implants and Norian bone cement

Current Concepts: Corrective Osteotomy for Extra-Articular Deformity Following a Distal Radius Fracture

Fracture malunion alters wrist and distal radioulnar joint (DRUJ) biomechanics, resulting in incongruence and instability of the DRUJ. Selected patients with painful functional limitation and significant deformity of the radius, but without advanced degenerative joint disease, may benefit from corrective distal radial osteotomy. Non-union and complications arising from metalwork are the most common reasons for reoperation. Surgeons should have a good understanding of risks and complications in order to fully inform their patients and manage expectations. This article reviews the biomechanical effects of radial malunion and the current concepts for treatment. Distal radial osteotomy is suitable for symptomatic patients with angular radial deformity and shortening. Evidence supports a volar approach without bone grafts for modest corrections. Bone grafts or synthetic bone substitutes are appropriate for larger corrections. Functional improvements are reported regardless of technique. Despite a high complication rate, patient satisfaction with the corrective radial osteotomy is high.

Corrective Osteotomy of Malunited Fractures of the Distal Radius Using a Combined Surgical Approach

Background: Malunited distal radius (DR) fractures following conservative treatment range from 6% to 80% of clinical observations. Surgical treatment is used to return the articular surface of the radius to original anatomical position and to restore the natural transfer of strength, wrist kinematics, and function of the entire hand. The aim of this research was to study and analyze the results of corrective osteotomy of malunited distal radius fractures using a combined approach. Methods: From 2008 to 2018, 43 patients with malunited DR fractures who underwent surgery using a combined approach were followed up. Long-term results (1 year after surgery) were studied in detail in 32 patients. Indications for surgery were determined taking into account, first, complaints of severe pain in the wrist during exertion, decreased hand strength, and limited mobility of the wrist. Results: Five patients (15.6%) reported a number of minor complications: intra-articular screw placement (2), incorrect reposition (1), transient neuropathy of the superficial branch of the radial nerve (1), and delayed fracture consolidation (1). In addition, another 5 patients reported the progression of wrist arthritis. Suppurations of the surgical wound and malunited fragments were not reported. Conclusions: During reconstructive interventions, a combined approach with palmar plating provides optimal conditions for corrective osteotomy, adequate reposition and plastic repair of the bone defect, and minimization of the number of complications.

Clinical impact of high-profile animal-based research reported in the UK national press

OBJECTIVES

We evaluated animal-based biomedical 'breakthroughs' reported in the UK national press in 1995 (25 years prior to the conclusion of this study). Based on evidence of overspeculative reporting of biomedical research in other areas (eg, press releases and scientific papers), we specifically examined animal research in the media, asking, 'In a given year, what proportion of animal research "breakthroughs"' published in the UK national press had translated, more than 20 years later, to approved interventions?'

METHODS

We searched the Nexis media database (LexisNexis.com) for animal-based biomedical reports in the UK national press. The only restrictions were that the intervention should be specific, such as a named drug, gene, biomedical pathway, to facilitate follow-up, and that there should be claims of some clinical promise.

MAIN OUTCOME MEASURES

Were any interventions approved for human use? If so, when and by which agency? If not, why, and how far did development proceed? Were any other, directly related interventions approved? Did any of the reports overstate human relevance?

RESULTS

Overspeculation and exaggeration of human relevance was evident in all the articles examined. Of 27 unique published 'breakthroughs', only one had clearly resulted in human benefit. Twenty were classified as failures, three were inconclusive and three were partially successful.

CONCLUSIONS

The results of animal-based preclinical research studies are commonly overstated in media reports, to prematurely imply often-imminent 'breakthroughs' relevant to human medicine.

Best Approaches in Distal Radius Fracture Malunions

PURPOSE OF REVIEW

Malunion remains a common complication in the treatment of distal radius fractures. The purpose of this review was to discuss the various approaches in planning and surgical management for extra- and intra-articular distal radius malunions.

RECENT FINDINGS

Several recent studies have reported good results with surgical correction of distal radius malunions utilizing a number of preoperative planning methods and surgical approaches. Three-dimensional models and custom cutting guides have recently become more popular, but their benefit in comparison to other methods remains unclear. Regardless of preoperative planning method or surgical approach, good results can be achieved with correction of distal radius malunion with careful attention to patient selection, indications, and surgical technique.

CaP cement is equivalent to iliac bone graft in filling of large metaphyseal defects: 2 year prospective randomised study on distal radius osteotomies

The purpose of this prospective randomised study was to compare the clinical and radiological outcomes of injectable CaP bone cement with corticocancellous bone graft used to fill voids after corrective opening wedge osteotomies in the distal radius. 17 women/3 men, median age 56 (51.3; 61.0), underwent an open-wedge osteotomy of a dorsal malunion in the distal radius randomised to filling the defect either with bone graft (10) or CaP bone cement (10). Dorsal titanium locking plates were used and the wrist was plastered for 8 weeks. Follow-ups for 24 months included X-rays, CT scans, VAS on wrist and iliac crest, grip strength, ROM, Quick-DASH and Gartland & Werley scores. No difference was found between the 2 groups as to clinical outcome or radiological results with no loss of reduction. One bone graft patient developed a pseudarthrosis and one CaP patient suffered a plate fracture 6 months post-operatively. CaP bone cement is a good alternative to bone graft as a void filler in open-wedge osteotomies of the distal radius. The procedure is shorter, easier with the post-operative advantage of no donor site pain. Level of Evidence Randomised controlled trial. Level I evidence.

A user's survey of the clinical application and content validity of the DASH (Disabilities of the Arm, Shoulder and Hand) outcome measure

STUDY DESIGN

Survey.

PURPOSE OF THE STUDY

To elicit feedback on the clinical use and content validity of the Disabilities of the Arm, Shoulder and Hand (DASH) outcome measure from frontline users of the instrument.

METHODS

A cross-sectional survey was administered to registered DASH users and inquired about how the DASH was being used and to identify the informational value of items of the DASH (content validity).

RESULTS

About 172 completed the survey. One or both of the DASH and/or QuickDASH were consistently (89.5%) being used. About 90% were using it in adults (21-65 years), and at least 70% were using it across the entire extremity, and to a lesser extent, 10% reported using it in isolated neck injuries. Most respondents (66.9%-75.8%) were using the DASH in musculoskeletal (MSK) disorders, with some applying it for other more unique or non-MSK conditions (2.5%-16.6%). All but 1 of the 30 DASH items had at least 10% endorsement as being informative, and 4 items were identified as being problematic by greater than 20%.

CONCLUSIONS

The DASH is being used as intended (whole extremity and MSK conditions), and in addition, it is being used in different body regions and diverse conditions.

LEVEL OF EVIDENCE

Not applicable (descriptive survey).

Orthogonal Plate Fixation With Corrective Osteotomy for Treatment of Distal Radius Fracture Malunion

PURPOSE

To report outcomes of patients with distal radius fracture malunions treated with corrective osteotomy and orthogonal volar and radial "90-90" plate fixation.

METHODS

We performed a retrospective review of all patients who underwent distal radius corrective osteotomy and 90-90 fixation from January 2008 through December 2014. Demographic data, injury history, prior treatments, and clinical examination values were recorded. Preoperative radiographic measurements were used to classify the type and severity of deformity. The outcomes were patient-reported pain levels, Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) functional scores, and radiographic outcomes. Secondary outcomes, including complications and the need for additional surgeries, were also noted.

RESULTS

Thirty-nine cases (31 extra-articular, 8 combined intra- and extra-articular) were included. At mean postoperative follow-up interval of 4 years, significant improvements were observed clinically in wrist flexion-extension arc, grip strength, pain, and Quick Disabilities of the Arm, Shoulder, and Hand scores. Radiographically, significant postoperative improvements were noted in ulnar variance, radial inclination, intra-articular stepoff, and radial tilt, with volarly and dorsally angulated malunions corrected to 9° and 7° of volar tilt, respectively. Twelve patients (31%) underwent additional surgery, the most common being plate removal in 7 patients, 3 of which involved removal of the radial plate.

CONCLUSIONS

For patients with symptomatic malunion of the distal radius, corrective osteotomy with 90-90 plate fixation is an effective treatment option for improving pain and restoring function for both volarly and dorsally angulated malunions, including malunions with an intra-articular component.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

[Are there any indications for surgery of distal radius malunion in elderly patients?]

Malunions of the distal radius are associated most of the time with disturbances of the distal radioulnar (DRU) joint. While a corrective osteotomy of the distal radius is a well-known procedure in younger patients, manual workers and active patients, is it justified in independent elderly patients above 70 years of age? These techniques improve function, reorient the articular surfaces, protect against complications such as degenerative osteoarthritis and stiffness of the wrist, and they improve DRU balance. Osteotomies performed with bone or artificial grafts have comparable outcomes. Either a volar or dorsal approach can be used depending on the orientation of the carpal articular surface of the radius and the need to lengthen the radius. If the patient is active and independent, the clinical benefit is higher when an osteotomy is done for significant malunions; urgent treatment of these older patients brings about additional costs and unclear benefits.

Shortening of the distal ulna to correct ulnar variance in osteoporotic wrist fractures treated with intra-focal pining

The aim of this study is to correct the ulnar variance in severe osteoporotic wrist fracture treated with intra-focal pining of the distal radius, with shortening osteotomy of the distal ulna. Thirteen patients, 12 females and one male, 61-83 years old, 6-year follow-up, were treated by intra-focal pining (kapandji). When preoperatively the ulnar variance did not return to a normal value comparing to the opposite wrist, a shortening osteotomy of the ulna was performed in one stage, 4 cm proximal to the ulnar head. The fractures healed 6-8 weeks with stability and normal motion: flexion 70°, extension 60° and pronation/supination 140°. There was no pain upon palpation of distal ulna and no sign of radial impingement. Concerning the ulnar variance and starting with nine neutral values at the normal wrist, we obtained eight negative and one neutral ulnar variance after surgery. In four cases of negative variance at normal wrist, we obtained four negative ulnar variances after surgery and two cases of ulnar non-union. In cases of dorsal comminution in wrist fracture with severe osteoporosis, intra-focal pining technique is able to restore all the radiological parameters, but it could not correct the inversion of ulnar variance relative to shortening of the radius. Avoiding secondary interventions, acute shortening osteotomy of the ulna performed is a procedure which allows restoring the ulnar variance without affecting carpal stability and the mobility.

Corrective distal radius osteotomy following fracture malunion using a fixed-angle volar locking plate

Post-traumatic distal radius deformity may cause severe morbidity, and corrective osteotomy is often necessary to realign the functional axis of the wrist to correct symptomatic malunion. The aim of this retrospective study was to review the short-term results of a single surgeon’s series of distalradius corrective osteotomies following fracture malunion using a fixed-angle volar locking plate for 20 patients(16 women) of an average age of 57 (range 19–83) years [corrected].At short-term follow up (average 14 months, range 12-15 months), no complications were noted and radiological union was confirmed in all cases at an average of 3 months. The average post-operative Disability of the Arm, Shoulder and Hand score was 13.48 (range 0-48.33) and an objective improvement was noted in movements at the wrist joint. A statistically significant improvement was achieved in ulnar variance, radial inclination, dorsal tilt, and supination.

Calcium phosphate cement augmentation after volar locking plating of distal radius fracture significantly increases stability

PURPOSE

Distal radius fractures represent the most common fractures in adults. Volar locking plating to correct unstable fractures has become increasingly popular. Although reasonable primary reduction is possible in most cases, maintenance of reduction until the fracture is healed is often problematic in osteoporotic bone. To our knowledge, no biomechanical studies have compared the effect of enhancement with biomaterial on two different volar fixed-angle plates.

METHODS

Human fresh-frozen cadaver pairs of radii were used to simulate an AO/OTA 23-A3 fracture. In a total of four groups (n = 7 for each group), two volar fixed-angle plates (Aptus 2.5 mm locking fracture plate, Medartis, Switzerland and VA-LCP two-column distal radius plate 2.4, volar, Synthes, Switzerland) with or without an additional injection of a biomaterial (Hydroset Injectable HA Bone Substitute, Stryker, Switzerland) into the dorsal comminution zone were used to fix the distal metaphyseal fragment. Each specimen was tested load-controlled under cyclic loading with a servo-hydraulic material testing machine. Displacement, stiffness, dissipated work and failure mode were recorded.

RESULTS

Improved mechanical properties (decreased displacement, increased stiffness, decreased dissipated work) were found in both plates if the biomaterial was additionally injected. Improvement of mechanical parameters after biomaterial injection was more evident in the Synthes plate compared to the Aptus plate. Pushing out of the screws was noticed as a failure mode only in samples lacking supplementary biomaterial.

CONCLUSIONS

Injection of a biomaterial into the dorsal comminution zone increases stability after volar locking plating of distal radius fractures in vitro.

Corrective osteotomy of the distal radius following failed internal fixation

INTRODUCTION

The purpose of this study was to quantify the clinical and radiographic outcomes after corrective osteotomy for malunions of the distal radius following failed internal fixation.

MATERIALS AND METHODS

Results of 18 patients (8 women, 10 men; mean age 41 years) are presented an average of 7 years after osteotomy of a malunited distal radius fracture. We assessed active range of motion, grip strength, radiographic alignment, pain and disability. Subjective and objective data were summarized using the modified Mayo Wrist Score and the point-score system of Fernandez.

RESULTS

Wrist motion, pain and deformity improved with the operation in all cases. The modified Mayo Wrist Score averaged 79 points. The scale of Fernandez indicated ten good, two fair and six poor results.

CONCLUSIONS

The results of this study suggest that the operative correction of a distal radius malunion following an unsuccessful internal fixation can be achieved with outcomes comparable to those reported after initial nonoperative treatment.

The use of bone grafts and substitutes in the treatment of distal radius fractures

The interest in developing biomaterials to augment fracture healing continues to grow. New products promise early return to function with minimal morbidity; however, indications to use these products remain unclear. An ideal bone graft material stimulates bone healing and provides structural stability while being biocompatible, bioresorbable, easy to use, and cost-effective. This article reviews the biology of bone grafts and the clinical evidence in the use of bone graft substitutes for the treatment of distal radius fractures.

Management of malunions of the distal radius

Despite encouraging results from small case series, correction of distal radius malunion remains a challenging procedure with uncertain outcomes. The most appropriate treatment for a distal radius malunion is prevention. If a symptomatic malunion is discovered, correction should be undertaken as early as possible. It is recommended that action be taken within six months of the primary injury to decrease the negative impact of soft-tissue contracture on the eventual reconstruction. Although some patients complain about residual problems after malunion surgery, corrective surgery has been shown to improve both radiographic and functional outcomes, and may prevent future secondary problems.

STATISTICAL ANALYSIS ON FUNCTIONAL AND RADIOGRAPHIC RESULTS AFTER USE OF LOCKED VOLAR PLATE FOR FRACTURES OF THE DISTAL RADIUS

Objectives: To evaluate the functional results from using a fixed-angle locked volar plate for treating fractures of the distal extremity of the radius, using the DASH (disorders of the arm, shoulder and hand) questionnaire and its radiographic correlation with the Lidström classification. Methods: Thirty patients with unstable fractures of the distal extremity of the radius were evaluated after they had undergone a surgical procedure consisting of open reduction and internal fixation using a fixed-angle locked volar plate, at the Military Police Central Hospital of Rio de Janeiro between 2008 and 2009. The results were assessed based on range of motion, DASH protocol scores and radiographies with the Lidström classification. Results: The mean age of the patients in the study was 51 years. The mean DASH score was 11.9 points. It was observed that the radiographic findings did not influence the DASH score. It was found that flexion, pronation, supination and radial deviation correlated with the DASH score. Conclusions: The study showed that subjective functional outcomes using the DASH protocol, obtained from using a locked volar plate to treat fractures of the distal extremity of the radius, are influenced by the range of motion, and especially by the flexion, supination, pronation and radial deviation of the wrist after surgery. There is no correlation between the radiological parameters of either the normal or the operated radius, and the subjective functional outcomes assessed using the DASH protocol.

Clinical outcomes of corrective osteotomy for distal radial malunion: a review of opening and closing-wedge techniques

BACKGROUND

Radial corrective osteotomy is an established but challenging treatment for distal radial malunion. There is ongoing discussion over whether an opening or closing-wedge osteotomy should be employed. The purpose of the present study was to retrospectively compare the clinical and radiographic results of conventional opening-wedge osteotomy with those of our closing-wedge technique.

METHODS

We retrospectively evaluated forty-two patients with extra-articular distal radial malunion who were managed with corrective osteotomy and were followed for a minimum of one year. Twenty-two patients were managed with radial opening-wedge osteotomy and interpositional bone graft or bone-graft substitute, and twenty were managed with simultaneous radial closing-wedge and ulnar shortening osteotomy without bone graft. The selection of the surgical procedure was determined by the surgeon. Each patient was evaluated on the basis of objective radiographic measurements and functional outcomes as determined on the basis of clinical examination, including range of wrist motion, grip strength, pain-rating score, Mayo wrist score, and Disabilities of the Arm, Shoulder and Hand (DASH) score.

RESULTS

The mean duration of follow-up was thirty-six months (range, twelve to 101 months) for the opening-wedge cohort and twenty-eight months (range, twelve to eighty-seven months) for the closing-wedge cohort. The two techniques were comparable in terms of complications. Postoperative volar tilt and ulnar variance improved significantly compared with the preoperative status in each cohort (p < 0.05). Restoration of ulnar variance to within defined criteria (-2.5 to 0.5 mm) was significantly more frequent in the closing-wedge cohort than in the opening-wedge cohort (p < 0.001). The postoperative mean extension-flexion arc of the wrist (p < 0.001) and Mayo wrist score (p = 0.008) were significantly better in the closing-wedge cohort. Differences between the two cohorts in terms of the pronation-supination arc, grip strength, pain-rating score, and DASH scores were not significant.

CONCLUSIONS

The closing-wedge osteotomy technique is an effective reconstructive procedure for the treatment of extra-articular distal radial malunion. It is significantly better than the opening-wedge osteotomy technique in terms of the restoration of ulnar variance, the extension-flexion arc of wrist motion, and the Mayo wrist score.

Calcium phosphate bone cement: a possible alternative to autologous bone graft. A radiological and biomechanical comparison in rat tibial bone

BACKGROUND

Donor site morbidity is a problem after autologous bone transplantation. An injectable CaP bone cement indicates properties similar to bone.

MATERIALS AND METHODS

Double osteotomies on rat tibias were performed. The intercalated segments were avascular (10), vascular (10), or avascular with Norian SRS(®) CaP bone cement replacing cancellous bone (10). Controls were non-operated contralateral tibias (15). All osteotomies were stabilised with an intra-medullary nail. After 8 weeks, all rats were killed. The harvested tibias were compared using X-ray, DEXA scanning, microCT scans and a biomechanical torsional test.

RESULTS

No difference in healing processes or biomechanical results has been found between the avascular bone graft, vascular bone graft and CaP bone cement groups.

CONCLUSION

The injectable CaP bone cement confirms its similarities to bone, implying that it can be used as an adjunct to secure bone fragments and as a possible alternative to autologous bone transplantation in clinical practice.

Effect of calcium phosphate bone cement augmentation on volar plate fixation of unstable distal radial fractures in the elderly

BACKGROUND

Calcium phosphate bone cement increases the stability of implant-bone constructs in patients with an osteoporotic fracture. The purpose of this randomized study was to determine whether augmentation of volar locking plate fixation with calcium phosphate bone cement has any benefit over volar locking plate fixation alone in patients older than sixty-five years of age who have an unstable distal radial fracture.

METHODS

Forty-eight patients (fifty unstable distal radial fractures) were recruited for this study. The mean patient age was seventy-three years. Surgical procedures were randomized between volar locking plate fixation alone (Group 1) and volar locking plate fixation with injection of calcium phosphate bone cement (Group 2). The patients were assessed clinically at three and twelve months postoperatively. Clinical assessments included determinations of grip strength, wrist motion, wrist pain, modified Mayo wrist scores, and Disabilities of the Arm, Shoulder and Hand (DASH) scores. Radiographic evaluations were performed immediately postoperatively and at one year following surgery. The adequacy of the reduction was assessed by measuring radial inclination, volar angulation, and ulnar variance.

RESULTS

The two groups were comparable with regard to age, sex, fracture type, injury mechanism, and bone mineral density. No significant differences were observed between the groups with regard to the clinical outcomes at the three or twelve-month follow-up examination. No significant intergroup differences in radiographic outcomes were observed immediately after surgery or at the one-year follow-up visit. Furthermore, no complication-related differences were observed, and there were no nonunions.

CONCLUSIONS

Augmentation of metaphyseal defects with calcium phosphate bone cement after volar locking plate fixation offered no benefit over volar locking plate fixation alone in elderly patients with an unstable distal radial fracture.

Evaluation of a fiber reinforced drillable bone cement for screw augmentation in a sheep model--mechanical testing

We evaluated the mechanical properties of a novel fiber reinforced calcium phosphate at time zero and after 12 weeks in vivo using a sheep long bone osteotomy model. Time zero data were obtained and compared by pullout testing of 4.5 mm bone screws from bone proper and overdrilled defects of 4.5 and 8 mm diameter. Defects were augmented with: polymethylmethacrylate (PMMA), calcium phosphate, and fiber reinforced calcium phosphate using cadaveric sheep tibiae. Twelve-week data were obtained from explanted tibiae of sheep that underwent unilateral tibial osteotomy surgery repaired with a locking compression plate. The most distal hole was overdrilled to 4.5 or 8 mm diameter, filled with fiber reinforced cement, drilled, tapped and a 4.5 mm screw was placed. Screw holding strength at t= 0 was significantly higher for reinforced when compared to nonreinforced cement, but not different from bone or PMMA in 4.5 mm defects. There was no difference in pullout strength for the 8 mm defect data. After 12 weeks fiber reinforced pullout strength increased by 45% and 8.9% for 4.5 and 8 mm defects, respectively, when compared to t= 0 testing. Fiber reinforced calcium phosphate bone cement can be drilled and tapped to support orthopedic hardware for trauma applications.

Extra-articular distal radius malunion: The phosphate cement alternative

Five consecutive patients (mean age: 40.4 yrs (range, 19-58 yrs)), with symptomatic distal radius malunion underwent corrective opening wedge osteotomy using phosphate cement as an alternative to bone autograft, at a mean 9 months (4-16mo) of fracture. Internal fixation used a plate placed just above the distal radioulnar joint, with soft-tissue release. Radiographic and functional parameters were measured before surgery, and at 6 months and 1 year. At a mean 32.4 months (range, 16-47mo), all patients were satisfied and all the osteotomies were united. At 1 year's follow-up, wrist range of motion reached 75% compared to the contralateral side. Two biopsies performed during plate removal showed osteoid tissue at the cement-bone junction. It is reasonable to consider injectable phosphate cement as a viable alternative to bone grafting in conjunction with surgical correction of distal radius malunion.

LEVEL OF EVIDENCE

level IV.

The role of locking technology in the hand

Locked fixed-angle plating in the hand and wrist helps to optimize outcomes following surgical fixation of select acute fractures and complex reconstructions. Select indications include unstable distal ulna head/neck fractures, periarticular metacarpal and phalangeal fractures, comminuted/multifragmentary diaphyseal fractures with bone loss (ie, combined injuries of the hand), osteopenic/pathologic fractures, nonunions and corrective osteotomy fixation, and small joint arthrodesis. Locked plating techniques in the hand should not be seen as a panacea for wrist and digital acute trauma and delayed reconstructions. An understanding of the biomechanics of fixed-angle plating and proper technical application of locking constructs will optimize outcomes and minimize complications. As clinical experience with locking technology in hand trauma broadens, new indications and applications will emerge. Currently, several systems are available. The specific implants share common features in their protocols for insertion, but unique differences in their design (ie, individual locking mechanisms, uniaxial vs polyaxial locking capability, metallurgy, and plate profiles) must be appreciated and considered preoperatively.

Osteotomy of distal radius fracture malunion using a fast remodeling bone substitute consisting of calcium sulphate and calcium phosphate

Malunion after a distal radius fracture can be treated with an osteotomy of the distal radius. Autologous iliac crest bone graft is often used to fill the gap, but the procedure is associated with donor site morbidity. In this study a novel fast resorbing biphasic bone substitute consisting of a mixture of calcium sulphate and calcium phosphate is used (Cerament BoneSupport AB, Sweden). Fifteen consecutive patients, with a mean age of 52 (27-71) years were included. All had a malunion after a distal radius fracture and underwent an osteotomy. A fragment specific fixation system, TriMed (TriMed, Valencia, CA), consisting of a Buttress Pin and a Radial Pin Plate were used for fixation and a calcium sulphate and calcium phosphate mixture as bone substitute. The patients were followed for 1 year. Grip strength increased from 61 (28-93)% of the contralateral hand to 85 (58-109)%, p < 0.001. DASH scores decreased from 37 (22-61) to 24 (2-49) p = 0.003. Radiographically all osteotomies healed. An increase of ulnar variance was noted during healing from 1.8 mm immediately postoperatively to 2.6 mm at final follow up. Osteotomy can increase grip strength and decease disability after a malunited fracture. In the present series the bone substitute was replaced by bone, but a minor loss of the achieved radiographic correction was noted in some patients during osteotomy healing. A more rigid fixation may improve the radiographic outcome with this kind of bone substitute.

In vitro surface reaction layer formation and dissolution of calcium phosphate cement-bioactive glass composites

Composites of hydrated calcium phosphate cement (CPC) and bioactive glass (BG) containing Si were immersed in vitro to study the effect of chemical composition on surface reaction layer formation and dissolution/precipitation behavior. The solutions used were 0.05 M tris hydroxymethyl aminomethane/HCl (tris buffer), tris buffer supplemented with plasma electrolyte (TE) with pH 7.4 at 37 degrees C, and this solution complemented with 10% newborn bovine serum (TES). The post-immersion solutions were analyzed for changes in Ca, PO(4) and Si concentrations. The reacted surfaces were analyzed using Fourier transform infrared (FTIR), and scanning electron microscopy with energy dispersive x-ray analysis. The sample weight variations after immersion were also determined. The results showed that the composition of the bioactive composite CPCs greatly affected their behavior in solution and the formation of apatite bioactive surface reaction layers. After immersion in the TE solution, Ca ions were taken up by all samples during the entire immersion duration. Initially, the P ion concentration increased sharply, and then decreased. This reaction pattern reveals the formation of an amorphous calcium phosphate layer on the surface of these composite CPCs. FTIR revealed that the layer was, in fact, poorly crystallized Ca-deficient carbonate apatite. The thickness of the layer was 12-14 microm and it was composed of rod-like apatite with directional arrangement. For immersion in the TES solution, the Ca and Si ion concentrations showed a similar behavior to that in TE, but the release rate of Si ions was higher. FTIR revealed that after TES immersion, not only did the typical, poorly crystallized, Ca-deficient carbonated apatite form, as it did in TE, but also the serum proteins co-adsorbed on the surface and thereby affected the surface reaction layer formation. A thinner apatite layer was formed and was composed of a micro-porous layer comprising rounded particles in a glue-like matrix. The addition of BG to the CPCs to create composite CPCs obviously is at the basis of this altered behavior of the cements. All data combined are useful for the design and optimization of degradable implant materials for use in bone tissue repair and regeneration procedures.