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The relative linear and angular displacements of proximal femoral reconstructions were compared within six different replacement techniques during ex vivo axial compression, mediolateral bending, and axial torsion in dogs. Each femur was osteotomized at 25%, 50%, or 75% of its length and the proximal portion subsequently replaced using one of six techniques. The reconstruction techniques included various combinations of proximal and distal fixation methods (graft fixation/distal fixation): (1) an allograft/prosthesis composite (APC) press-fit proximally and cemented distally (press-fit/cement); (2) APC cemented proximally and distally (cement/cement); (3) APC cemented proximally and the host bone/graft interface double plated (cement/plates); (4) APC cemented proximally and secured distally with bicortical screws (cement/screws); (5) APC secured proximally and distally with bicortical screws (screws/screws); (6) Segmental proximal femoral replacement cemented into the distal femur without an allograft (no graft/cement). For axial compression and mediolateral bending, the combined resection lengths revealed no differences in linear and angular displacements, respectively, between reconstruction methods. During axial torsion, the cement/cement technique allowed larger angular displacements than all but the press-fit/cement technique which had larger displacements than the cement/screws, screws/screws, and no graft/cement groups (p < 0.0001). Overall, the measured implant stability was solid and consistent as evidenced by small amounts of relative displacement and small error values.

Tibial tunnel placement during endoscopic anterior cruciate ligament (ACL) reconstruction has received increased emphasis in the recent literature. Appropriate tunnel length is a critical technical consideration. A tunnel that is too short results in graft extrusion, necessitating supplemental fixation techniques. A tunnel that is too long may make distal fixation and femoral tunnel placement difficult. A simple rule is proposed that allows for correct tunnel length and allows placement of the bone plug consistently within the tibial tunnel, allowing interference screw fixation.

A failure analysis of interference screw fixation was performed to test the hypothesis that bovine and/or elderly human cadavers are appropriate models for bone-patellar tendon-bone anterior cruciate ligament (ACL) reconstruction fixation studies. Failure mode is an important criterion for validating experimental models. The bovine, young human, and elderly human failure loads were 799 +/- 261 N, 655 +/- 186 N, and 382 +/- 118 N, respectively, and the failure modes were 75%, 69%, and 30% tissue failures, respectively. The similarities between the bovine and young human models in failure loads and failure modes indicate that bovine models are appropriate for ACL reconstruction fixation studies. The statistically significant differences between the young human and elderly human models in failure loads and failure modes indicate that elderly human cadavers are not an appropriate model for ACL reconstruction fixation studies. The differences in failure modes are consistent with previous studies using elderly human cadavers in which the predominant failure mode was bone block pullout. The tissue failures observed in the bovine and young human models contradict previous studies suggesting fixation strength is the weakest link in bone-patellar tendon-bone ACL reconstruction. Results of linear regression modeling showed statistically significant correlations between insertion torque and failure load (R2 = 0.44, P < 0.0001) and interference (defined as the screw outer thread diameter minus the tunnel-bone block gap) and insertion torque (R2 = 0.18, P = 0.003) when data from all models was combined. Results for the bovine model multiple regression showed a statistically significant regression of insertion torque (linear) and interference (quadritic) versus failure load (R2 = 0.56, P = 0.02). Regression slopes for screw diameter (P = 0.52) and gap size (P = 1.00) were not statistically significant. These results indicate that insertion torque and interference are independent predictors of failure load and should be included in future interference screw studies in addition to bone block dimensions, tunnel size, gap size, and screw diameter. Clinicians may consider using insertion torque and interference as indicators of postoperative graft fixation regarding rehabilitation decisions.

The aim of this clinical report is to describe the outcome of 7 patients regarding the efficiency of a vertebral body replacement with rib bone for destructive lesions in the thoracic spine. In these patients, an autologous bone block shaped from four rib segments, was used as a vertebral body replacement. In order to compose the bone block, the ribs were fused by means of one or two commercialized titanium screws. In a retrospective study the following parameters were analysed: neurological status, rate of bony fusion, primary correction gain, secondary correction loss. Mean time of follow-up was eleven months (range 6-20). Neurological improvement was found in 83.3% of patients treated with ventral decompression. Immediate postoperative gain of correction was 9.4 angle degrees, secondary loss of correction was 11.4 angle degrees, the latter resulting from the impression of the rib segments into the adjacent vertebrae. Radiological bony fusion of the rib implants could be observed in all cases. To avoid a secondary loss of correction, ventral fusion using an osteosynthesis plate and, in singular cases, the dorsal implantation of a fixateur interne is advantageous. An additional advantage of this new method is that autologous bone harvesting is accomplished during the surgical approach, rendering a separate approach for this purpose superfluous (thus shortening operation time, reducing morbidity and operative complications). We conclude from our results that the composed rib block is an attractive alternative vertebral body replacement which provides sufficient stability and osteogenic capacity.

Rigid internal fixation with miniplates and screws has enabled reconstructive surgeons to position bony segments precisely. Unfortunately, our present systems have been associated with a potential adverse effect on ultimate craniofacial growth and development. Also, they may be palpable, necessitating secondary procedures for removal of the hardware. We have been involved in an ongoing study evaluating the efficacy of a commercially developed biodegradable system. In this study, we compared biodegradable lag screw fixation with traditional titanium screw fixation in full-thickness, membranous bone grafts harvested from the zygomatic arches to the snout in a rabbit model. The results were compared with standard hematoxylin and eosin stains and laser densometry. Although this study adds further credence to the resorption of bone grafts, those secured with the polyglycolic acid screws demonstrated significantly less resorption than those maintained in position by traditional methods.

Between 1990 und 1992, 22 patients with bone and soft tissue defects were treated by open segmental bone transport according to Ilizarov, and 20 of these were followed up over a period of 18 months after removal of the external fixator. In 19 cases the bone defect could be filled by callus distraction only, while 1 patient needed additional spongeous bone transplantation because of delayed ossification. In 1 case amputation was necessary because of extensive fistula carcinoma of the resected bone and soft tissue. Closure of soft tissue defect was achieved in 14 patients simultaneously with docking of the bone segments. In 5 patients additional skin transplantation was needed, and in 1 case a latissimus dorsi flap had to be transferred because of unstable scar formation. Transporting vital bone simultaneously with the overlying tissue into a defect allows for limb salvage even in poor biological conditions and in patients with vascular problems. Open bone transfer has extended the range of methods available for the treatment of bone and soft tissue defects.

This paper describes an approach to the management of radial longitudinal deficiency. Early treatment includes manipulation and splintage prior to realignment of the carpus on the forearm. Twelve patients are presented in which a comparison is made between centralisation and radialisation surgical techniques. Preoperative distraction allowed radialisation without excision of a part of the carpus in five out of six patients. In contrast, centralisation with carpal excision was necessary in 5 out of 6 patients not treated by preoperative distraction. It remains to be seen whether radialisation is a superior procedure to centralisation in the longer term. However, radialisation in theory allows greater protection for the distal ulnar physis, maintains maximal length, and allows optimal wrist motion. Late treatment of radial longitudinal deficiency includes techniques of bone lengthening and correction of radial deviation deformity. Three cases are presented in which the Ilizarov technique was used to lengthen the forearm and to correct deformity. The complications of forearm lengthening are high but these techniques do allow significant correction of deformity.

Between 1988 and 1992, 54 patients with complicated tibial non-union were treated by tibio-fibular fusion. In 6 cases of comminuted fracture the operation was performed within the first 2 months, especially in the case of distal fractures. Fifteen patients suffered from aseptic tibial pseudarthrosis, and further 6 from an additional defect. In 25 patients treatment for infected non-union was needed and in 3 cases tibio-fibular synostosis was induced after segmental transport and non-docking. Most of the patients had conspicuous soft tissue lesions, and 14 required transplantation of a regional or free flap. So far 46 patients have completed their treatment. In 44 cases full weight-bearing on the affected leg is possible. In 2 cases the treatment failed. None of our patients required limb amputation at the site of synostosis. In 13 cases the follow-up showed clearly that the axis was not right, in 11 cases a varus deformity. Most of these deviations have not been corrected because of poor quality of the soft tissue coverage. We suggest this method be used as part of a technique allowing the fibula to stay in its original position while providing tibio-fibular fusion by interposition of autologous cancellous bone grafting and transfixing screws. Additional stabilization might be achieved by using an external fixator, for preference. Partial weight-bearing is allowed after 2 weeks and full weight-bearing is attained on average after 3-4 months. Concerning the initial lesion, the primary aim of the treatment should be the recovery of full weight-bearing without an additional device and without chronic infection.(ABSTRACT TRUNCATED AT 250 WORDS)

The prosthodontic aspects of a new method of reconstruction after maxillectomy are described. A custom-made titanium mesh tray filled with crushed autogenous hip bone is interposed between two layers of a pedicled temporal muscle flap. The titanium mesh tray is fabricated on a cast carved to represent the anatomy of the reconstructed maxilla. The tray is designed so that, after healing, osseointegrated implants can be placed in preplanned positions in the reformed maxilla. The buccal sulcus is recreated with a free mucosal graft from the contralateral cheek at the second implant surgical stage. The prosthodontic restoration is completed after healing of the free mucosal graft.

A new set of instruments with a special saw, a guide and a punch has been developed for harvesting of cancellous bone for small grafts. In a cadaver experiment use of the instruments was compared with the conventional open technique. Within half the operation time, nearly the same quantity of cancellous bone could be salvaged. In 29 clinical cases, bone defects resulting from 4 bone cysts, 6 enchondromas, 5 pseudarthroses and 5 fractures were closed with cancellous bone grafts harvested by means of the new instruments. In the case of 9 bone tumors the punches were used to obtain biopsy specimens, and sufficient tissue for the exclusion of malignancy was obtained in all 9. With the new instruments we are able to harvest cancellous bone for small grafts by a minimally invasive method.

Surgical reconstruction of cranial deformities and synostosis is occasionally accompanied by incomplete bone growth to cover all areas of cranial vault that have been exposed in the correction. The restrictive nature of some forms of synostosis require more bone in the repair than is available using the child's natural skull for autogenous bone cranioplasty. Rib and iliac crest autografts have been used with success. These grafts must be harvested form a remote site with increased morbidity. A split-thickness skull autograft is the cranioplasty material of choice but children under the age of 6 years may lack the skull thickness needed to use this technique. Perforated demineralized bone matrix has been transplanted in 46 operations in 42 patients from 1990 to 1995 for repair of residual skull defects in children having previously undergone craniofacial repairs, for primary reconstruction of the cranial vault for patients with synostosis and for repair of skull defects resulting from trauma and skull tumor excisions. The vast majority of grafts have resulted in complete closure of the defect, providing a matrix for new bone formation. These patients are presented. Surgical techniques of cranial defect repair with perforated demineralized bone matrix are discussed.

A prospective study was made of 14 patients with mandibular continuity defects not involving the condyle who underwent mandibular reconstruction with autogenous particulate cancellous and bone marrow, autologous fibrin adhesive, and custom-made inferior border titanium cribs. The design and fabrication of the cribs were based on the prediction tracing of the mandibular defects from panoramic radiographs. The mandibular arch form, facial contour, and alveolar bone height were restored with high accuracy. The average follow-up time was 30 months. Autologous fibrin adhesive held the bone particles firmly together and accelerated the bone graft healing, which enabled the early removal of the intermaxillary fixation and restoration of the masticatory function. The results of this study demonstrated that the use of inferior border titanium crib designed from a simple, practical, and inexpensive technique is valuable in mandibular reconstruction.

This study was undertaken to determine the incidence of serious neurologic injury associated with the harvesting of cranial bone grafts. A personal series of 1000 consecutive bone-grant harvestings (cranial, iliac, costal, tibial, and mandibular) was examined in detail for complications. Then a survey of members of the International Society of Craniofacial Surgeons was performed, and data were compiled on complications of bone-graft harvestings performed by the respondents. Data also were compiled on neurologic complications related to cranial bone-graft harvestings performed by other surgeons which the respondents were aware of through direct personal knowledge, medicolegal review, the medical literature, or other channels. No neurologic complications were associated with any of the 586 cranial bone grafts taken in the authors' series. The survey respondents reported that they had performed 12,672 cranial bone-graft harvestings. Temporary neurologic complications were associated with graft harvesting in 3 cases (0.02 percent). The respondents also identified 8 other neurologic complications (4 permanent and 4 temporary) associated with cranial bone-graft harvestings performed by other surgeons. Five cases were performed by surgeons having little or no experience in harvesting cranial bone grafts, and three were performed by surgeons having only limited training. It appears that cranial bone grafts can be harvested with an extremely low incidence of serious complications by surgeons who have had proper training. Techniques are suggested for safe harvesting of cranial bone grafts, as well as for detecting and managing complications when they arise.

The use of costochondral grafts in the acute trauma setting is controversial. This new technique has recently been utilized in two patients with severe condylar head fractures using a newly designed Synthes AO mesh plate with microscrews (0.8 mm) and 1.5-mm fixation. The technique provides superb rigid fixation. This fixation technique is multifaceted and can be used in all settings of acute and chronic costochondral graft replacement.

A series of 283 patients who suffered from cervical spondylosis, herniated disc, or traumatic pathology of the cervical spine were operated on using an anterior approach. Intersomatic arthrodesis was performed in 350 cases; in every case, a threaded bone graft was screwed into the intervertebral orifice using the technique described by the author. Fusion was achieved within 6 months in 93% of cases with 92 autologous grafts and in 81% of cases with 258 heterologous grafts. In addition to the use of threaded intervertebral holes and threaded bone grafts, the Cloward technique was modified by the introduction of a set of new instruments, which largely replaced the ones previously use. These included a low-speed motor with different drills and trephines, a trephine guide retractor, and an intersomatic retractor.

Bone transport, along with allied techniques of compression distraction, offer exciting new treatment alternatives for the difficult problem of segmental bone loss from acute trauma. Many factors must be considered before indicating these treatment methods, because it is clear that many of the problems that existed with more conventional methods also exist with these techniques. The indications for amputation vs. limb salvage must always be considered in these severe injuries. In less severe injuries with minimal bone loss and soft-tissue injury exposing well-vascularized segments of bone, traditional methods of stabilization, soft-tissue coverage, and grafting lead to more rapid healing times and return to function for patients. These techniques are reserved for the most severe type of injuries for which treatment times are long and complications not infrequent. Therefore, methods to speed treatment, avoid complications, and increase patient acceptance should be actively sought. The great advantage of these techniques is that the vast majority of the reconstruction is done on the injured limb segment, with minimal need for extensive donor-site defects.

With a follow-up extending to six years, the use of morcelized cancellous grafts and a cemented stem has so far functioned well clinically and led to impressive restitution of bone stock in challenging femoral revision situations. Essentially the method involves coating cements with a truly biological coating of allograft cancellous chips.

This article has reviewed several experimental studies that address certain aspects of the use of rigid fixation in clinical craniofacial surgery. The effect of rigid fixation on growth was studied in an infant Rhesus monkey model. It showed that osteotomy and fixation resulted in subtle changes in skull shape and that the severity of the deformity was related to the complexity of the fixation employed. Deformities were seen with wire fixation alone, however. A study using a rabbit model showed that the revascularization and resorption of onlay bone grafts immobilized with a microscrew occurred primarily in the cancellous portion of the graft. This led Chen et al to speculate that the volume of cranial bone grafts persists better than with iliac crest grafts, because they contain relatively less cancellous bone and more cortical bone, which is slower to revascularize and resorb. Fiala et al studied the artifacts seen in CT and MR scans associated with plate and screw fixation devices. They showed that, compared with stainless steel and vitallium, titanium resulted in less "starburst" and "black hole" artifact in CT and MR images, respectively. Amarante et al compared butyl-2-cyanoacrylate adhesive fixation with fixation by plates and screws of osteotomized bone segments in a minipig model. They found it to be as effective as plates and screws for bone fixation in this model. In the future, this material, together with resorbable plates and screws, may provide a means of fixation of the craniofacial skeleton and can be anticipated to receive further experimental and clinical study.

A review of a new technique for the harvesting of split (outer-table) calvarial bone grafts is presented. The use of calvarial bone grafts for facial reconstructive surgery has become more commonplace in recent years. Low donor site morbidity and availability of adequate amounts of membranous bone in close proximity to the facial surgical site make its use particularly desirable. Unfortunately, the occasional complications associated with the harvesting of these grafts can be severe, including dural tears and/or hemorrhage from a dural sinus, as well as late hematomas and meningitis. The technique herein described involves the use of a long malleable blade in a reciprocating saw. The malleability of the blade allows it to conform to the shape of the skull while elevating split grafts almost as wide as the blade is long. Twenty separate grafts were harvested in 18 patients. The largest measured 7 x 10 cm. The grafts were further contoured after harvesting and used in 37 sites. No grafts splintered, and no donor site complications were encountered. While care must of course be exercised with any technique, this one is believed to be a safe and dependable method for the harvesting of split calvarial grafts for facial reconstruction.

The physiology of bone healing, regeneration, and bone transfer is discussed from the dual perspectives of basic physiology and the application to clinical situations of bone transfer. Recommendations are made regarding clinical applications for the site, orientation, and fixation of grated materials. Rationale for the use of vascularized transfers is presented.

Bone graft surgery is the basis of all craniofacial surgery. The use of bone grafts in the craniofacial region has changed from a basic trial-and-error concept of surgical triumph to the understanding of the fundamental concepts of bone healing and bone physiology. The search for the super graft continues, and may become a reality before the end of the millennium.

Interference screw fixation is frequently used in anterior cruciate ligament reconstruction with the bone-patellar tendon-bone graft. There have been no data available about the influence of screw diameter and insertion torque on primary stability. We designed a cadaveric study using paired knees to analyze the comparative effectiveness of 20-mm long screws of different diameters (9 mm versus 7 mm) and the significance of torque during screw insertion. Testing to failure was performed in a tensiometer with a crosshead speed of 200 mm/min. After slippage of a bone peg in the 7-mm screw specimens, the experiment was repeated in each specimen with a 9-mm screw fixation. Maximum tensile force was greater at the femoral insertion than at the tibial site. Results of refixations with 9-mm screws were only slightly inferior to the original 9-mm screw fixation specimens. Our results further showed that the torque can be used as a predictor of the stability of the bone block but cannot be used as an indicator for the strength of the reconstruction. The 7-mm screws are not recommended for tibial fixation. Failed 7-mm screw fixations can be replaced by 9-mm screws and refixations were successful in our study model.

A retrospective study was made of 22 consecutive patients who underwent mandibular reconstruction with a Dacron (Osteo-mesh, Xomed Inc, Jacksonville, FL) tray technique from September 1988 to April 1992. Free autogenous iliac bone, in the form of particulate cancellous chips and marrow, was densely packed into the Dacron tray, that was adapted to bridge the mandibular segmental defect. Sixteen cases underwent uneventful healing with the formation of a continuous bony bridge and union with the remaining mandible. The pattern of bone remodeling and rate of resorption in these cases were assessed by sequential panoramic radiographs taken up to 3 years postoperatively. The mean horizontal dimension of the mandibular defects was 75 mm and the mean vertical reconstructed height was 25 mm. When the grafted bone was radiographically of uniform density, it progressed into a mature trabecular pattern matching that of the normal mandible. However, when there were areas of radiolucency, most likely from inadequate condensation of the graft, such areas were not replaced by bone in the long term. The bony height at both ends and the middle of the reconstructed segment underwent reasonably even resorption and retained about 80% of the bony height over a 3-year period. The rate of resorption was highest in the first 6 months and stabilized at about 2 years. There were six failures, all showing significant irregular bony resorption prior to tray removal.

We have developed reasonably strong but bioabsorbable osteosynthetic screws, pins and nails made of ultra high strength poly-L-lactide (PLLA) and evaluated their use in 143 patients. The PLLA implants have the highest strength among those reported to date. They lose about 10% of their initial strength within 8 weeks, about 40% within 4 weeks and nearly 100% within 20 weeks in vivo. The patients were aged from 9 to 78 years, and the follow up was from 2 to 6 years. The implants were used for fixation of bone grafts in 84 patients, peri- and intra-articular fractures in 49, after osteotomy in 8, and in 2 others. Bony union was not achieved in only one case. In the early stages of the study, breakage of screws occurred in 12 cases (8%), mostly because of an inappropriate size of tap; these problems have not occurred after improvement of the tapping system. There were no cases with abnormal blood tests, infection or foreign body reaction.

Bone transport is moving into the avenues of orthopaedic medicine by creating new alternatives to former methods of treatment. It is a challenging limb salvage procedure that uses the Ilizarov External Fixator. Cooperation and commitment from the patient and orthopaedic team can create exciting results.

The authors have used allografts for reconstruction of the cruciate ligaments in over 600 cases since 1985. Advantages are the reduced operative trauma and the unlimited availability of high-quality grafts even in multiple ligament reconstructions. Arthroscopic techniques are available for reconstruction of the anterior and the posterior cruciate ligament, which makes arthrotomies and large skin incisions unnecessary. The grafts of choice are the bone-patellar tendon-bone preparation and the Achilles tendon with bone bloc. No specific complications were observed with the use of allograft material in this series. Results show a high subjective acceptance of the procedure among the patients, with a high rate of return to pre-injury sports activities following ACL reconstruction. Objective stability was restored in over 70% of these cases. All cases with posterior instability had 3+ posterior drawer preoperatively. At follow-up, almost normal stability had been restored in 50%. Further research must focus on the biological processes that take place during incorporation of these tissues and on better techniques of graft processing and sterilisation. At present, the risk of disease transmission must be considered and discussed with the patient.

Percutaneous bone grafting with a specially devised milling cutter was used in 21 patients with nonunion or delayed union of fractures of the tibial shaft. Union was obtained in 18. The technique is safe, simple and can be done under local anaesthesia.

The strength of saw-harvested vs. osteotome-harvested Smith-Robinson iliac crest grafts from five fresh frozen cadavers was compared. Matched pairs of grafts were harvested, one with a saw and the other with an osteotome from equivalent locations on the two iliac crests of each pelvis. Grafts were tested to failure in axial compression, and load-displacement curves were recorded for each test. Yield load and displacement, ultimate load, and stiffness were calculated, and statistical analysis was performed with the Student t test and three-way analysis of variance. Evaluation of the 66 pairs of grafts revealed that saw-harvested grafts were consistently stronger than were matched grafts harvested with an osteotome. The middle third of the iliac crest produced significantly stronger grafts, and those harvested from younger donors were significantly stronger than those obtained from older donors. Of even greater clinical relevance, saw-harvested grafts were stiffer than osteotome-harvested grafts. Based on these findings, it is recommended that iliac crest grafts harvested for spine fusion be obtained with an oscillating saw rather than with an osteotome.

The current technique and instrumentation for contained morselized allograft with cement in dealing with femoral loosening associated with loss of bone stock is described. With a follow-up extending to 6 years, this method has proved effective in the management of these difficult problems.

Replacement arthroplasty of the hip may require restoration of bone stock to provide support for the acetabular implant and to restore anatomy and leg lengths. This article discusses the indications, surgical technique, results, and controversies of using bulk autograft bone to provide cup support for primary hip replacement in hip dysplasia. In addition, the use of allograft bone to restore bone stock in the revision situation is covered. The indications, surgical technique, and results of the use of both morsellized and bulk allograft bone are presented.

The Rochester bone trephine is a useful instrument for performing small joint arthrodesis in the foot. The technique involves harvesting a dowel graft from the iliac crest and then inserting the graft into a recipient bed across the small joints in the foot. Minimal surgical trauma and patient discomfort result from this technique. Three cases are presented to illustrate the usefulness and diversity of this system.

A prospective study of 32 patients was performed to analyze black pigmentation in the soft tissue covering titanium miniplates. This soft tissue was compared with the soft tissue covering Champy stainless steel plates. All plates were removed 8 months after application. Macroscopically visible pigmentation was found in 25.6% of the soft tissue covering titanium miniplates and in none of the soft tissue covering Champy stainless steel plates. Microscopically visible pigmentation was found in 71.8% of the soft tissue covering titanium miniplates and in 65.3% of the soft tissue covering Champy stainless steel plates. Energy-dispersive x-ray analysis of the soft tissue covering titanium miniplates revealed only the presence of titanium dioxide. In the soft tissue near Champy stainless steel plates, chromium, nickel, iron, and molybdenum were found. Electron microscopy showed titanium dioxide to be mainly deposited between the collagen fibers, whereas stainless steel particles were mainly found in giant cells.

A quick and simple method of trephining moderate amounts of cancellous bone (up to 6 cc) from the iliac crest via an anterior approach is presented. The advantages of this technique are that no muscle or ligamentous attachments are disturbed and postsurgical morbidity is low.

Revision, and complicated primary total knee arthroplasty (TKA), may present with significant structural bony defects. Allograft offers blocks of material that can be shaped to the defect. The opportunity to gain a biological bond may theoretically enhance loading conditions and enhance any subsequent surgery. However, the biomechanical and biological issues of immune response, infection, graft incorporation, resorption, and load transfer render allografting a powerful but problematic technology.

Bone grafting of osseous defects in primary or secondary total knee arthroplasty remains a popular and often indispensable solution to reconstructive problems. Solutions to contained, uncontained, and massive defects of both the tibia and femur are presented, as well as several options for reconstruction of deficient or ruptured extensor mechanisms.

Rigid internal fixation of the craniomaxillofacial skeleton has become commonplace in osseous reconstructive procedures of the face. While miniplates are useful in many traumatic, reconstructive, and congenital anomaly cases, they are often unnecessary. Lag screw fixation is routinely used in the mandible and has the advantage of maximal stability when compared with other fixation techniques. These principles can similarly be applied in a variety of situations in the upper facial skeleton, including fracture and bone graft fixation, as well as in pediatric craniofacial surgery. We review the technique and appropriate indications and demonstrate via case examples this diversity of applicability for using lag screw techniques. Finally, results of 83 cases in which this technique has been used will be reviewed, including complications.

Recent advances in microvascular surgery have made it possible to reconstruct large skeletal defects with autogenous bone grafts on a vascular pedicle. Experimental studies have demonstrated that vascularized bone grafts have superior blood flow and osteocyte survival when compared with nonvascular grafts. This improves the union rate and allows full incorporation of cortical bone, remodeling, and graft hypertrophy. Clinical experience over the past decade demonstrates that 80% to 90% of these grafts are ultimately successful, allowing limb salvage in complex reconstructive cases. However, the technique is technically demanding, has a relatively high complication rate, and requires prolonged immobilization and rehabilitation. Thus, vascularized bone grafts should only be used when simpler reconstructive techniques are unlikely to succeed.

The use of several calcium phosphate (Ca-P) materials for bone repair, augmentation, substitution and as coatings on metal implants has gained clinical acceptance in many dental and medical applications. These Ca-P materials may be of synthetic or natural origin, available in different physical forms (dense or macroporous, particles or blocks) and are used in bulk as coatings for metallic and non-metallic substrates or as components in composites, cements and bioactive glasses. Biodegradation or bioresorption of calcium phosphate materials implies cell-mediated degradation in vitro or in vivo. Cellular activity during biodegradation or bioresorption occurs in acid media; thus the factors affecting the solubility or the extent of dissolution (which in turn depends on the physico-chemical properties) of the Ca-P materials are important. Enrichment of the microenvironment due to the release of calcium and phosphate ions from the dissolving Ca-P materials affects the proliferation and activities of the cells. The increase in the concentrations of the calcium and phosphate ions promotes the formation of carbonate apatite which are similar to the bone apatite. The purpose of this invited paper is to discuss the processes of biodegradation or bioresorption of Ca-P materials in terms of the physico-chemical properties of these materials and the phenomena involved including the formation of carbonate apatite on the surfaces and in the vicinity of these materials. This phenomenon appears to be related to the bioactivity of the material and the ability of such materials to directly attach to bone and to form a uniquely strong material-bone interface.

A new implant material, Ionogran (Ionos, Medizinische Produkte GmbH & Co. K.G., Germany), is evaluated in a series of 60 cases requiring augmented bone grafting for major bone defects. The material, an ionomeric porous micro implant (IMI), is stable, non-degradable, osteoconductive and biocompatible. It promotes the formation of osteoid and displays a dynamic surface activity which stimulates the process of repair. In the compromised situation of a large cavity following curettage and cryotherapy, Ionogran when mixed with a mulch of autogenous cancellous bone is a valuable filler, providing a direct osteoid bond with host bone, and a permanent scaffold which maintains shape, length and form of the affected part. It replaces allogenic bone grafts and the problems associated with that technique.

The importance of calvarial bone grafting in craniomaxillofacial trauma and facial reconstructive surgery is now widely recognized. Numerous harvesting techniques have evolved to optimize the desired thickness, size, shape, and curvature for a particular reconstructive need. At the same time, donor site selection and morbidity must be considered. This report includes a discussion of several currently utilized calvarial bone graft harvesting techniques, with emphasis on minimizing complications and morbidity. Choice of optimal harvesting technique and donor site for specific reconstructive situations will likewise be discussed. Finally, the specific morbidity in our multi-institutional calvarial bone graft harvest series of 121 patients and over 350 grafts will be reviewed.

As there are only a finite number of materials suitable for orthopaedic reconstruction, considerable effort has been devoted recently to investigating ways of altering the surface chemistry of prosthetic materials without altering their bulk properties. Ion beam implantation is one such technique which is appropriate for orthopaedic reconstructive materials. This paper investigates the early effect of ion beam modification on cellular attachment of bone derived cells using a prototype device which measures the strength of attachment of individual cells to a silicon substratum. The results point to several conclusions. (1) There is no evidence that ion beam implantation with nitrogen, phosphorus, manganese or magnesium produces increased adhesion of human bone derived cells. (2) Surface etching with hydrofluoric acid, electron bombardment and thermal oxidation increases the strength of attachment between cells and substrata. (3) There is a correlation between wettability and rate of cellular attachment to oxygen implanted substrata during the first 2 h after cellular seeding. However, the increase in cellular attachment cannot be entirely explained by the change in critical surface tension or via increased fibronectin attachment to the substrata.