Dorsal Plating of Unstable Distal Radius Fractures Using a Bio-Absorbable Plating System and Bone Substitute

Polylactic acid bioabsorbable implants of the hand: A review

In the treatment of hand fractures, metal implants are often used to allow early range of motion and a stable fixation. Although they provide adequate bone union, metal implants have been known to cause joint stiffness, painful or prominent hardware, and adhesions, often leading to another surgery for hardware removal. Bioabsorbable implants have been shown to offer comparable results for fracture fixation in the hand while removing the complications seen with retained hardware. In this article, we review biomechanical and clinical studies focused on bioabsorbable implants made of polylactic acid used for orthopedic hand injuries in order to promote their continued use and future research.

Biopsies from the Distal Radius after Implantation of Calcium Phosphate Cement

Background: Calcium Phosphate (CaP) bone cement is gradually replaced by new bone when used as a gap-filler. Details of the re-modelling process are still unclear. Uncertainty is also present as to the possible release of cement particles during the resorption phase causing local soft tissue reactions. The objective of this study was to perform a comprehensive histological investigation of the injectable CaP bone cement used as a void filler in corrective radius osteotomies and adjacent tissue reactions.

Methods: Fourteen patients, median age 56 years (18–72), 4 men/10 women, underwent removal of distal radius plates (11 dorsal/3 volar) due to tenosynovitis-like symptoms. Eleven study patients went through corrective osteotomies with CaP bone cement and three were control patients. Previous surgery in three controls consisted in (1) corrective osteotomy with bone graft (dorsal plate), and (2) plated distal radius fractures (1 dorsal/1 volar plate). Biopsies were taken of bone-cement-bone junctions (11), bone-bone graft-bone junctions (1), bone (2) and juxtaposing soft tissue (14). The interval from corrective CaP cement surgery to biopsy was median 1.1 (0.6–2.3) years.

Results: Biopsies of bone-cement junctions showed the different stages of new bone formation from CaP to immature bone and later mature well-organised bone. The cement showed signs of osteoclast-mediated resorption. Cement particles, macrophages, multinucleated giant cells (MNGC) and plasma cells were observed in most soft tissue biopsies. MNGC with internalised particles were seen. Macrophages were found along and/or within tendon sheaths in all patients in both groups, but rarely containing cement particles.

Conclusions: Gradual re-modelling of the cement into well-organised bone was observed confirming osteoclast–osteoblast coupling. There was no indication that cement particles were the cause of the tenosynovitis-like symptoms.

Radiological, Clinical and Functional Outcomes of Combined Dorsal and Volar Locking Plate Osteosynthesis for Complex Distal Radius Fractures

PURPOSE

The purpose of this study was to assess the short- to mid-term radiologic, clinical, and functional outcomes of patients treated with combined dorsal and volar locking plating for internal fixation of complex, comminuted, intra-articular, distal radius fractures.

METHODS

We performed a retrospective review of 34 patients treated with combined dorsal and volar locking plates for the internal fixation of complex, comminuted, intra-articular distal radius fractures. Radiographic and clinical parameters were recorded at a mean of 48 months after surgery. Activities of daily living and quality of life were assessed by the Disabilities of the Arm, Shoulder, and Hand and Patient-Rated Wrist Evaluation questionnaires.

RESULTS

Compared with the contralateral wrist, the treated wrist regained 73% of flexion, 81% of extension, 86% of ulnar deviation, 90% of radial deviation, 98% of pronation, 99% of supination, and 93% of grip strength. Mean Disabilities of the Arm, Shoulder, and Hand and Patient-Rated Wrist Evaluation scores were 11 (range, 0-78) and 11 (range, 0-77), respectively. Radial height and radial inclination were restored anatomically in 24% and 41% of patients, respectively, while volar tilt and ulnar variance were restored in 68% of patients.

CONCLUSION

The overall functional and radiologic outcome of patients with comminuted intra-articular complex distal radius fractures treated with the combined dorsovolar plate osteosynthesis was good to excellent.

LEVEL OF EVIDENCE

Therapeutic IV.

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.

Volar long locking compression plate fixation for distal radius fractures with metaphyseal and diaphyseal extension

Comminuted distal radial fractures with metaphyseal and diaphyseal extension are uncommon and remain a challenge to treat. The purpose of this study was to assess the radiographic and functional outcomes of treatment with the volar long locking compression plate (LCP) system for distal radius fractures with metaphyseal and diaphyseal extension. This retrospective study was performed on 22 consecutive patients who were treated with open reduction and internal fixation with the application of a 2.4-mm-extra-long LCP volar distal radius plate. Patients were evaluated based on clinical signs and radiography studies. The average time to fracture union was 16 weeks. The volar tilt was restored to a mean of 10.1°. The radial length and radial inclination were restored to a mean of 12.8 mm and 23.6° at final follow-up, respectively. The mean loss of radial length was -1.0 mm at final follow-up as compared with the contralateral extremity. The average ulnar variance was positive 0.1 mm at final follow-up with a congruent distal radioulnar joint. The degree of collapse after fixation between immediate postoperative and final follow-up visit was -0.1 mm. Using the demerit-point system of the Gartland and Werley rating system, 14 results were rated as excellent, 5 as good and 1 as fair. DASH scores averaged 10.1 points. Based on our experience, the volar long LCP is useful in the management of comminuted fractures of the distal radius, in which there is proximal extension into the diaphysis and can avoid or minimize the complications of external fixation or dorsal bridging distraction plate.

Locking versus nonlocking palmar plate fixation of distal radius fractures

This study compared functional and radiological outcomes after treatment of extension-type distal radius fractures with conventional titanium nonlocking T-plates or titanium 1.5-mm locking plates. A total of 60 patients were included and followed for 4 to 7 years after receiving nonlocking T-plates (group A; n=30) or locking plates (group B; n=30) with and without dorsal bone grafting. Bone grafting was significantly more often performed in the nonlocking group to increase dorsal fracture fixation and stability (P<.003). Pre- and postoperative and follow-up values for palmar tilt, radial inclination, radial shortening, and ulnar variance were recorded. Age, sex, and fracture type were similarly distributed between the 2 groups. Postoperative and follow-up evaluation revealed equal allocation of intra-articular step formation and osteoarthritic changes to both groups. The overall complication rate was 25%. Compared with the nonlocking system, patients undergoing locking plate fixation presented with statistically significantly better values for postoperative palmar tilt (5.53° vs 8.15°; P<.02) and radial inclination (22.13° vs 25.03°; P<.02). However, forearm pronation was significantly better in group A (P<.005). At follow-up, radial inclination tended to approach a statistically significant difference in favor of group B. All clinical assessment, including Mayo wrist score, Disabilities of the Arm, Shoulder, and Hand score, Green and O'Brien score, Gartland and Werley score, visual analog scale score, and grip strength, yielded no statistically significant difference between the 2 groups. Locking plates seem to provide benefits regarding surgical technique and comfort, improvement in implant anchorage (especially in osteoporotic bone), and reduce the necessity of additional bone grafting.

Fixation of comminuted distal radius fractures with a mixture of calcium phosphate and calcium sulfate cement

Distal radius fracture alignment and stabilization can be a surgical challenge in the face of severe comminution and bone loss. We describe a technique using a calcium phosphate/sulfate bone cement, as an adjunct to internal fixation. This bone cement is biocompatible, osteoconductive, and sets quickly with an isothermic reaction. The use of bone cement eliminates the need for primary autologous bone grafting and allows for easier reduction and retention of reduction at the time of surgery. Bone cement is employed for the following purposes in comminuted fractures: (1) to fill a void due to lost or crushed cancellous bone, (2) to hold larger unstable fragments while hardware is placed, and (3) to retain fragments too small to take hardware. Available bone cements, studies involving the use of bone cement for distal radius fractures, indications, and surgical technique will be reviewed.

A biomechanical comparison of a biodegradable volar locked plate with two titanium volar locked plates in a distal radius fracture model

BACKGROUND

Volar plating is commonly used in the management of distal radius fractures; bioresorbable plates have attractive features. We compared a bioresorbable plate with a latest generation and an established locked titanium plate.

METHODS

Twenty-four fresh-frozen radii (12 pairs) were assigned to three mean bone mineral density-matched groups of eight radii each. A standardized extraarticular distal radius fracture was created and plated using one implant type per group. Postplating stiffness and displacement were studied in a first axial-loading test (15 cycles at 250 N). Next, biodegradation was simulated by 4 weeks' immersion in phosphate-buffered saline, followed by a second axial test. Finally, the specimens underwent cyclic loading (2,400 cycles at 250 N).

RESULTS

It is clear from the initial test that the LCP plate was significantly stiffer and displaced less than the bioresorbable plate. The outcome of the postimmersion tests is that one bioresorbable plate failed early on after 4 weeks' immersion, and the remaining bioresorbable plates and the T plates did not differ significantly. Cyclic tests conclude that the LCP plate was significantly superior to the other systems. One T plate and four of the bioresorbable plates failed, but none of the LCP plates failed. In the bioresorbable constructs, stability, time to failure, and bone mineral density were significantly correlated.

CONCLUSIONS

The LCP plate was biomechanically superior and may be generally recommended for the volar plating of distal radius fractures. Except one plate failure, the bioresorbable plate was similar to the T plate in the quasi-static tests and should, therefore, be considered for clinical studies, with patient selection confined, initially, only to candidates with good bone stock quality.

Locked volar plating for unstable distal radial fractures: clinical and radiological outcomes

We studied 40 patients treated with locked volar plates for unstable distal radial fractures. Outcome was assessed at a mean of 59 weeks, both radiologically and functionally using the Disability of the Arm, Shoulder and Hand (DASH) questionnaire, range of motion and grip strength. The complication rate in our series was 48%. In 11 cases, screw penetration into the radiocarpal joint occurred as a consequence of postoperative collapse. Of these, 25% had malunited and 12.5% ruptured their extensor pollicus longus (EPL) tendon. Functionally, when compared with the contralateral side, 74% of extension, 67% of flexion, 91% of pronation and supination and 81% of grip strength were regained. The mean DASH score was 23. Although locked volar plates can achieve good results in the management of unstable distal radial fractures, there remains a high major complication rate. They should be used with caution particularly in fractures with significant metaphyseal comminution.

A retrospective follow-up of ankle fracture patients treated with a biodegradable plate and screws

BACKGROUND

Biodegradable fixation implants have been developed to avoid secondary hardware removal. The aim of this study was to retrospectively follow-up ankle fracture patients treated with a biodegradable plate and screws, and to evaluate the clinical outcome and occurrence of complications.

METHODS

Fifty-seven ankle fracture patients treated with biodegradable implants were invited, and a total of 50 were available to participate in this study. The follow-up included a review of each patient's medical records, evaluation of radiographs, fracture reduction classification, and functional scoring.

RESULTS

There were 36 lateral malleolar and 14 bimalleolar fractures. No perioperative complications occurred. Average follow-up time was 17 months. All fractures healed. Fracture alignment was classified as anatomical in 49 patients and good in 1 case. The mean Olerud and Molander functional ankle score at final follow-up was 86. Eight patients had postoperative complications. These included delayed wound healing in 1 case, 3 cases of deep-vein thrombosis, and 4 soft tissue reactions.

CONCLUSIONS

According to the results of this retrospective study, the biodegradable implants used yielded fracture healing and functional results comparable to those previously reported after conventional metal fixation.

The use of a biodegradable mesh plate to augment grafting of an acetabular defect: Laboratory investigation and clinical pilot study

We used a biodegradable mesh to convert an acetabular defect into a contained defect in six patients at total hip replacement. Their mean age was 61 years (46 to 69). The mean follow-up was 32 months (19 to 50). Before clinical use, the strength retention and hydrolytic in vitro degradation properties of the implants were studied in the laboratory over a two-year period. A successful clinical outcome was determined by the radiological findings and the Harris hip score. All the patients had a satisfactory outcome and no mechanical failures or other complications were observed. No protrusion of any of the impacted grafts was observed beyond the mesh. According to our preliminary laboratory and clinical results the biodegradable mesh is suitable for augmenting uncontained acetabular defects in which the primary stability of the implanted acetabular component is provided by the host bone. In the case of defects of the acetabular floor this new application provides a safe method of preventing graft material from protruding excessively into the pelvis and the mesh seems to tolerate bone-impaction grafting in selected patients with primary and revision total hip replacement.

Evaluation of a novel nanocrystalline hydroxyapatite paste Ostim in comparison to Alpha-BSM - more bone ingrowth inside the implanted material with Ostim compared to Alpha BSM

Background

The purpose of this study was to evaluate the performance a newly developed nanocrystalline hydroxyapatite, OSTIM^® following functional implantation in femoral sites in thirty-eight sheep for 1, 2 or 3 months. Ostim^® 35 was compared to an established calcium phosphate, Alpha BSM^®.

Methods

Biomechanical testing, μ-CT analysis, histological and histomorphological analyses were conducted to compare the treatments including evaluation of bone regeneration level, material degradation, implant biomechanical characteristics.

Results

The micro-computed tomography (μCT) analysis and macroscopic observations showed that Ostim^® seemed to diffuse easily particularly when the defects were created in a cancellous bone area. Alpha BSM^® remained in the defect.

The performance of Ostim was good in terms of mechanical properties that were similar to Alpha BSM^® and the histological analysis showed that the bone regeneration was better with Ostim^® than with Alpha BSM^®. The histomorphometric analysis confirmed the qualitative analysis and showed more bone ingrowth inside the implanted material with Ostim^® when compared to Alpha BSM ^® at all time points.

Conclusions

The successful bone healing with osseous consolidation verifies the importance of the nanocrystalline hydroxyapatite in the treatment of metaphyseal osseous volume defects in the metaphyseal spongiosa.

Bio-resorbable versus metal implants in wrist fractures: a randomised trial

BACKGROUND

Distal radius fractures are often surgically treated if insufficient reduction has been achieved or after conservative treatment has failed. Treatment using metal implants often demands a secondary operation to remove the implant. A bio-resorbable implant (in this study the Reunite osteosynthesis plate by Biomet Inc) should obviate the need for a secondary operation with equal functional results.

MATERIALS AND METHODS

Thirty-two patients with a distal radius fracture were assigned to treatment with either a bio-resorbable implant (N = 19) or a metal implant (N = 13). Both groups received the same postoperative care and were followed for 52 weeks in the outpatient clinic. The hypothesis of this study was a decrease in re-operation rate in the experimental group with equal functional results.

RESULTS

Five out of 19 patients treated with the Reunite plate were re-operated and four out of 13 treated with metal implants needed a secondary operation. In both implants, equal functional results in Range of Motion and DASH scores were found.

CONCLUSION

There were no significant differences between the experimental and control group with respect to re-operations, DASH scores and Range of Motion. Because of the higher initial costs and equal results, the use of bio-resorbable implants must be considered carefully.

Biomechanical in vitro evaluation of the effect of cyclic loading on the postoperative fixation stability and degradation of a biodegradable ankle plate

The effect of cyclic loading on the postoperative fixation stability of a biodegradable ankle plate was tested biomechanically during 12 weeks of hydrolytic degradation. Fracture of the lateral malleolus was simulated, and the parameters of cyclic loading were chosen to represent the physiological conditions during the healing period. Additionally, the effect of cyclic loading on degradation was investigated by measuring the inherent viscosities. In Group I, the cyclic loading was conducted in four phases with gradual increases in estimated walking distance and speed during the healing period. In Group II, cyclic loading was conducted after 12 weeks. Group III was used as a control for inherent viscosity measurements. None of the specimens failed under cyclic loading. No significant differences were found between the loaded groups in any of the parameters measured. Additionally, no significant difference was found in inherent viscosities at 12 weeks. The initial fixation stability provided by the biodegradable ankle plate remains biomechanically unchanged over 12 weeks. Cyclic loading, applied either during or after 12 weeks of hydrolytic degradation, does not seem to have any clinically relevant effect on the fixation stability or the degradation properties.

Clinical results of absorbable plates for displaced metacarpal fractures

PURPOSE

To present the clinical results of a study of unstable metacarpal fractures treated with absorbable plates.

METHODS

Between July 2004 and June 2006, 12 patients (14 fractures) who presented with displaced, unstable, metacarpal fractures had open reduction and internal fixation. The overall clinical follow-up results and radiographic controls at 6, 12, and 26 weeks after surgery are reported. The clinical outcome was assessed by the Disabilities of the Arm, Shoulder, and Hand score and the visual analogue pain scale.

RESULTS

The involved fingers showed an average final total active motion of 234 degrees (range, 220 degrees-265 degrees). No deformity of rotation>5 degrees was observed in any patient in the clinical follow-up evaluation. One patient had a loss of reduction with a palmar angle of the metacarpal axis of 20 degrees in the sagittal plane. A second patient with secondary loss of reduction required surgical revision, at which time internal fixation was performed by using a titanium plate. Complications included keloid formation and prolonged soft-tissue swelling for more than 6 weeks in 3 patients. No wound margin necrosis, infection, pseudarthrosis, sinus formation, or osteolysis was observed. Bone consolidation was achieved reliably within 6 weeks both clinically and radiologically. The Disabilities of the Arm, Shoulder, and Hand score results 6 weeks after surgery were an average of 30 points compared with 13 after 12 weeks and 3 points after 26 weeks. The visual pain scale showed mean values of 18 after 6 weeks, 2 after 12 weeks, and 0.2 after 26 weeks.

CONCLUSIONS

Absorbable plates are suitable for use in hand surgery and allow early range of motion in combination with an additional orthosis of the hand (as described) for 3 weeks. In the early and medium-term postoperative course, no osteolysis or sterile sinus formation was observed. Metal plates are still the gold standard; however, surgical implants made of amorphous copolymer of L-lactide and glycolic acid in combination with an orthosis constitute a useful and reliable means of metacarpal fracture treatment.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.