[Circular soft tissue defect after prolonged application of a strangulating compression stocking]. / Zirkulärer Weichteildefekt nach prolongiertem Belassen eines strangulierenden Kompressionsstrumpfes.

Wearing a compression stocking over a longer period of time can lead to deep skin and soft tissue defects. This article presents a case of a circular necrosis with an exposed tendon of the tibialis anterior muscle and the Achilles tendon. The use of a peroneus brevis muscle flap led to an adequate coverage of the exposed Achilles tendon. Due to the short operating and anesthesia times, this flap is a good option for lower leg reconstruction, particularly in multimorbid patients. This case raises awareness of the importance of adequate patient training before commencing compression therapy.

Severity of injury predicts subsequent function in surgically treated displaced intraarticular calcaneal fractures.

BACKGROUND: The treatment of displaced, intraarticular calcaneal fractures (DIACFs) remains challenging and the best treatment choices remain controversial. The majority of patients will have some lasting functional restrictions. However, it is unclear which patient- or surgeon-related factors predict long-term function. QUESTIONS/PURPOSES: We determined (1) the impact of patient- and surgeon-related factors on function of patients after internal fixation of DIACFs and (2) whether severity of injury correlated with subsequent function. METHODS: We retrospectively reviewed all 210 patients operatively treated for 242 DIACFs between 2000 and 2003; of these, 127 patients (60%) with 149 fractures were available for followup at a minimum of 69 months (average, 95 months; range, 69-122 months). Severity of injury was quantified by the classifications of Sanders and Zwipp Function was quantified using the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot score, an adjusted Zwipp score, the Foot Function Index (FFI), and the SF-36 physical and mental component summary (PCS and MCS) scores. RESULTS: At latest followup, the median AOFAS score was 77, the median Zwipp score was 60, the median FFI was 27, and the median SF-36 PCS and MCS scores were 44 and 55, respectively. The foot-related scores and the SF-36 PCS negatively correlated with the severity of injury, work-related injuries, and bilateral fractures. CONCLUSIONS: We found the severity of a DIACF related to subsequent foot function and quality of life. Both fracture severity classifications predicted function. Anatomic reconstruction of the shape and articular surfaces of the calcaneus leads to predictable function in the medium to long term.

Subcutaneous emphysema of the upper extremity after elbow arthroscopy.

Subcutaneous emphysema of the upper extremity is rare. Crepitation on physical examination and visible gas on radiographs raise the concern of gas gangrene due to gas-producing bacteria. Rapid establishment of a differential diagnosis is necessary to initiate proper treatment. We present a case of subcutaneous emphysema after elbow arthroscopy caused by a noninfectious genesis. A 59-year-old woman with loose bodies in her left elbow due to mild degenerative joint disease and restricted range of motion was offered an elbow arthroscopy with removal of loose bodies and arthrolysis. Postoperatively, the elbow was actively put alternatively in maximum extension and flexion. On the first postoperative day, rapidly ascending swelling and subcutaneous crepitation starting from the hand to the forearm were noted. There was no clinical evidence of infection. Radiographs showed subcutaneous air. Frequent blood tests and clinical evaluation ruled out a potentially life-threatening bacterial infection, and the signs resolved after 1 week without surgical treatment. Presumably, the intensive postoperative range-of-motion exercises led to a sucking in of air into the wound during each movement. This case illustrates that it is important to differentiate nonbacterial from bacterial causes of soft-tissue gas formation to initiate the appropriate treatment.

The influence of playing level on functional ankle stability in soccer players.

OBJECTIVE: The aim of this study was to compare the functional ankle stability between professional and amateur soccer players as well as controls. MATERIALS AND METHODS: Thirty professional soccer players, 30 amateur soccer players and 30 controls were evaluated. All participants completed a questionnaire. Range of motion (ROM), peroneal reaction time (PRT) and ankle position sense were measured. Balance control was investigated with the Biodex Stability System, measuring the stable level 8 and the unstable level 2. RESULTS: Professional soccer players cited significantly more frequent ankle sprains than all other groups (P = 0.002). They showed a significantly decreased dorsiflexion of the right foot (amateur: P = 0.017; controls: P = 0.004), an increased pronation of both feet (amateurs: right: P = 0.0048, left: P = 0.006; controls: right: P = 0.017, left: P = 0.007) and a decreased supination of the left foot in comparison to all other groups (amateurs: P = 0.003; controls: P = 0.004). Balance control showed no significant differences among all groups. Significant differences in angle reproduction were observed between professionals and amateurs for the left ankle joint at the positions of 105° (P = 0.0018) and 140° (P = 0.013). Professionals (P = 0.004) and amateurs (P = 0.001) showed a significantly delayed PRT of the right peroneus longus muscle compared to controls. In addition, the PRT of the right peroneus brevis muscle was significantly increased in professional soccer players in comparison to controls (P = 0.017). CONCLUSIONS: Professional soccer players have shown more frequent ankle sprains, limited ROM, and delayed PRT of the right leg which reflects the higher risk of functional ankle instability due to intensified work-related use of feet. Therefore, proprioceptive exercises of the ankle in daily training programs are recommended in order to minimize the risk of ankle injuries and improve functional ankle stability.

Fifth metatarsal avulsion fracture: a rational basis for postoperative treatment.

BACKGROUND: Lacking rational basis for the postoperative treatment of fifth metatarsal avulsion fractures. METHODS: Biomechanical test of stability of tension banding and screw fixation of fifth metatarsal avulsion fractures in cadaver specimen, sonographic measuring of the maximum cross-section of the peroneus brevis muscle, electromyographic examinations of the activity of the peroneus brevis muscle at different loads and means of immobilization. RESULTS: The forces acting on the base of the fifth metatarsal bone during voluntary activation of the peroneus brevis muscle or activation in the gait cycle are of the same magnitude as the failure forces of internal fixation. Immobilization of the talocrural joint achieves no reduction in muscle activation. Partial weight bearing reduces muscle activation. CONCLUSIONS: The postoperative treatment after osteosynthesis of fifth metatarsal avulsion fractures should be partial weight bearing. For safety reasons we add an elastic ankle orthesis to prevent supination. A below-knee cast is not necessary.

Transsection of the rectus abdominis muscle in the treatment of acetabular fractures: operative technique and outcome in 21 patients.

BACKGROUND: A standard ilioinguinal approach is often insufficient for reduction and stabilization of the medial acetabular wall and the dorsal column in acetabular fractures. To avoid extended approaches, we have used a medial extension of the approach by transverse splitting of the rectus abdominis muscle. We have thus been able to reduce and stabilize transverse and oblique fractures of the dorsal column and the medial acetabular wall and to fix plates in a mechanically better position below the pelvic brim. To evaluate the procedure, especially the risk of abdominal hernia, we started a prospective study. PATIENTS AND METHODS: Over 2 years, we treated 21 consecutive patients using a transverse splitting of the rectus abdominis muscle-either as an extension of the standard ilioinguinal approach or in combination with parts of this approach or a Kocher-Langenbeck approach. The patients were evaluated clinically and radiographically after 1 year. RESULTS: The clinical and radiographic results were excellent or good in 18 patients. Complications occurred in 5 patients. No hernias were observed. CONCLUSIONS: Our small study indicates that the procedure described is a useful and safe complement to the intrapelvic approaches. The procedure does not provide better reduction than extended approaches, but may help to avoid them in some cases.

Effect of modification of hydroxyapatite/collagen composites with sodium citrate, phosphoserine, phosphoserine/RGD-peptide and calcium carbonate on bone remodelling.

This study describes the early interface reaction of cancellous bone to a nanocrystalline hydroxyapatite cement containing type I collagen (HA/Coll) and its modifications with sodium citrate (CI), calcium carbonate (CA), phosphoserine (P) and phosphoserine plus RGD-peptide (RGD). Cylindrical implants of HA/Coll and its modifications were inserted into the tibia of Wistar rats. We analysed 6 specimens per group at days 2, 4, 7, 14 and 28. CI, P and RGD modifications showed improved material properties (finer microstructure and higher compressive strength) compared to CA and HA/Coll implants. The powder X-ray diffraction (XRD) showed that the addition of P and CI led to an increase of alpha-TCP peaks while the diffraction patterns of the non-modified cement (HA/Coll) were quite similar with that of natural bone. All of the implants healed without adverse reactions. A significantly higher number of TRAP-positive osteoclasts were observed around CI, RGD and P on day 7 compared to CA and HA/Coll. Around CI, P and RGD a significantly delayed increase of ED1-positive mononuclear cells was detected. The amount of direct bone contact after 28 days was significantly higher around CI, P and RGD compared to CA and HA/Coll implants. The addition of CI, P and RGD appears to enhance bone remodelling at the early stages of bone healing, leading to increased bone formation around HA/Coll composite cements.

Coating of titanium implants with collagen, RGD peptide and chondroitin sulfate.

Coating of orthopaedic implants with extracellular bone matrix components was performed to enhance bone healing. Titanium pins of 0.8mm diameter were coated with type I collagen (Ti/Coll), RGD peptide (Ti/RGD) or type I collagen and chondroitin sulfate (Ti/Coll/CS). Uncoated pins (Ti) served as control. The pins were inserted as intramedullary nails into the tibia of male adult Wistar rats. Six specimens of each group were retrieved at 4, 7, 14 and 28 days. All implants healed uneventfully without adverse reactions. ED 1-positive macrophages appeared in higher numbers around Ti/RGD at day 4 and around Ti at day 14 after implantation (p < 0.05). TRAP-positive osteoclasts and precursors were abundant around Ti/Coll/CS at day 7 (p < 0.05). A significant increase in osteopontin-positive osteoblasts was seen around Ti/Coll/CS implants at days 7 and 14, and around Ti/RGD at day 14 (p < 0.05). At day 28, 62% of Ti, 76% of Ti/Coll, 85%* of Ti/RGD and 89%* of Ti/CoIl/CS (*p < 0.05) implants were covered with newly formed lamellar bone. The addition of extracellular matrix components significantly enhances bone remodelling in the early stages of bone healing around Ti implants, eventually leading to increased new bone formation at the implant surface after 4 weeks.

Joint-Sparing Corrections of Malunited Chopart Joint Injuries.

Treatment of malunion and nonunion at the Chopart joint aims at axial realignment of the midfoot to the hindfoot and restoration of the normal relationship of the lateral and medial columns of the foot. In carefully selected patients with intact cartilage, joint-preserving osteotomies are feasible at all 4 bony components of the Chopart joint to restore near-normal function. Priority should be given to the anatomic reconstruction of the talonavicular joint because it is essential for global foot function. Patients must be counseled about the risk of progressive arthritis or osteonecrosis necessitating late fusion.

Foot and ankle fractures during childhood: review of the literature and scientific evidence for appropriate treatment.

Foot and ankle fractures represent 12% of all pediatric fractures. Malleolar fractures are the most frequent injuries of the lower limbs. Hindfoot and midfoot fractures are rare, but inadequate treatment for these fractures may results in compartment syndrome, three-dimensional deformities, avascular necrosis and early post-traumatic arthritis, which have a significant impact on overall foot and ankle function. Therefore, the challenges in treating these injuries in children are to achieve adequate diagnosis and precise treatment, while avoiding complications. The objective of the treatment is to restore normal anatomy and the correct articular relationship between the bones in this region. Moreover, the treatment needs to be planned according to articular involvement, lower-limb alignment, ligament stability and age. This article provides a review on this topic and presents the scientific evidence for appropriate treatment of these lesions.

As fraturas do tornozelo e do pé representam 12% de todas as fraturas pediátricas. Fraturas maleolares são as lesões mais frequentes dos membros inferiores; fraturas do retropé e mediopé são raras, mas o seu tratamento inadequado pode resultar em síndrome de compartimento, deformidades tridimensionais, necrose avascular e osteoartrose pós-traumática precoce, as quais apresentam impacto significativo na função global do tornozelo e pé. Portanto, os desafios no tratamento dessas lesões na criança são o diagnóstico adequado e tratamento preciso para se evitarem as complicações. O objetivo do tratamento é restaurar a anatomia normal e a relação articular correta entre os ossos da região. Além disso, o tratamento deve ser planejado de acordo com acometimento articular, o alinhamento dos membros inferiores, a estabilidade ligamentar e a idade. O algoritmo de tratamento dos traumas complexos do tornozelo e pé na infância é descrito. Este artigo apresenta uma revisão sobre o tema e as evidências científicas para o tratamento adequado dessas lesões.

Histological analysis of the structural composition of ankle ligaments.

BACKGROUND: Various ankle ligaments have different structural composition. The aim of this study was to analyze the morphological structure of ankle ligaments to further understand their function in ankle stability. METHODS: One hundred forty ligaments from 10 fresh-frozen cadaver ankle joints were dissected: the calcaneofibular, anterior, and posterior talofibular ligaments; the inferior extensor retinaculum, the talocalcaneal oblique ligament, the canalis tarsi ligament; the deltoid ligament; and the anterior tibiofibular ligament. Hematoxylin-eosin and Elastica van Gieson stains were used for determination of tissue morphology. RESULTS: Three different morphological compositions were identified: dense, mixed, and interlaced compositions. Densely packed ligaments, characterized by parallel bundles of collagen, were primarily seen in the lateral region, the canalis tarsi, and the anterior tibiofibular ligaments. Ligaments with mixed tight and loose parallel bundles of collagenous connective tissue were mainly found in the inferior extensor retinaculum and talocalcaneal oblique ligament. Densely packed and fiber-rich interlacing collagen was primarily seen in the areas of ligament insertion into bone of the deltoid ligament. CONCLUSIONS: Ligaments of the lateral region, the canalis tarsi, and the anterior tibiofibular ligaments have tightly packed, parallel collagen bundles and thus can resist high tensile forces. The mixed tight and loose, parallel oriented collagenous connective tissue of the inferior extensor retinaculum and the talocalcaneal oblique ligament support the dynamic positioning of the foot on the ground. The interlacing collagen bundles seen at the insertion of the deltoid ligament suggest that these insertion areas are susceptible to tension in a multitude of directions. CLINICAL RELEVANCE: The morphology and mechanical properties of ankle ligaments may provide an understanding of their response to the loads to which they are subjected.

Comprehensive histological evaluation of bone implants.

To investigate and assess bone regeneration in sheep in combination with new implant materials classical histological staining methods as well as immunohistochemistry may provide additional information to standard radiographs or computer tomography. Available published data of bone defect regenerations in sheep often present none or sparely labeled histological images. Repeatedly, the exact location of the sample remains unclear, detail enlargements are missing and the labeling of different tissues or cells is absent. The aim of this article is to present an overview of sample preparation, staining methods and their benefits as well as a detailed histological description of bone regeneration in the sheep tibia. General histological staining methods like hematoxylin and eosin, Masson-Goldner trichrome, Movat's pentachrome and alcian blue were used to define new bone formation within a sheep tibia critical size defect containing a polycaprolactone-co-lactide (PCL) scaffold implanted for 3 months (n = 4). Special attention was drawn to describe the bone healing patterns down to cell level. Additionally one histological quantification method and immunohistochemical staining methods are described.

Increased bone remodelling around titanium implants coated with chondroitin sulfate in ovariectomized rats.

Coating titanium implants with artificial extracellular matrices based on collagen and chondroitin sulfate (CS) has been shown to enhance bone remodelling and de novo bone formation in vivo. The aim of this study was to evaluate the effect of estrogen deficiency and hormone replacement therapy (HRT) on the osseointegration of CS-modified Ti implants. 30 adult female, ovariectomized Wistar rats were fed either with an ethinyl-estradiol-rich diet (E) to simulate a clinical relevant HRT or with a genistein-rich diet (G) to test an alternative therapy based on nutritionally relevant phytoestrogens. Controls (C) received an estrogen-free diet. Uncoated titanium pins (Ti) or pins coated with type-I collagen and CS (Ti/CS) were inserted 8weeks after ovarectomy into the tibia. Specimens were retrieved 28days after implantation. Both the amount of newly formed bone and the affinity index (P<0.05) were moderately higher around Ti/CS implants as compared to uncoated Ti. The highest values were measured in the G-Ti/CS and E-Ti/CS groups, the lowest values for the E-Ti and G-Ti controls. Quantitative synchrotron radiation micro-computed tomography (SRµCT) revealed the highest increase in total bone formation around G-Ti/CS as compared to C-Ti (P<0.01). The effects with respect to direct bone apposition were less pronounced with SRµCT. Using scanning nanoindentation, both the indentation modulus and the hardness of the newly formed bone were highest in the E-Ti/CS, G-Ti/CS and G-Ti groups as compared to C-Ti (P<0.05). Coatings with collagen and CS appear to improve both the quantity and quality of bone formed around Ti implants in ovarectomized rats. A simultaneous ethinyl estradiol- and genistein-rich diet seems to enhance these effects.

Healing properties of surface-coated polycaprolactone-co-lactide scaffolds: a pilot study in sheep.

The aim of this pilot study was to evaluate the bioactive, surface-coated polycaprolactone-co-lactide scaffolds as bone implants in a tibia critical size defect model. Polycaprolactone-co-lactide scaffolds were coated with collagen type I and chondroitin sulfate and 30 piled up polycaprolactone-co-lactide scaffolds were implanted into a 3 cm sheep tibia critical size defect for 3 or 12 months (n = 5 each). Bone healing was estimated by quantification of bone volume in the defects on computer tomography and microcomputer tomography scans, plain radiographs, biomechanical testing as well as by histological evaluations. New bone formation occurred at the proximal and distal ends of the tibia in both groups. The current pilot study revealed a mean new bone formation of 63% and 172% after 3 and 12 months, respectively. The bioactive, surface coated, highly porous three-dimensional polycaprolactone-co-lactide scaffold stack itself acted as a guide rail for new bone formation along and into the implant. These preliminary data are encouraging for future experiments with a larger group of animals.

Embroidered and surface coated polycaprolactone-co-lactide scaffolds: a potential graft for bone tissue engineering.

Tissue engineering and regenerative techniques targeting bone include a broad range of strategies and approaches to repair, augment, replace or regenerate bone tissue. Investigations that are aimed at optimization of these strategies until clinical translation require control of systemic factors as well as modification of a broad range of key parameters. This article reviews a possible strategy using a tissue engineering approach and systematically describes a series of experiments evaluating the properties of an embroidered and surface coated polycaprolactone-co-lactide scaffold being considered as bone graft substitute for large bone defects. The scaffold design and fabrication, the scaffolds properties, as well as its surface modification and their influence in vitro are evaluated, followed by in vivo analysis of the scaffolds using orthotopic implantation models in small and large animals.

Effect of chondroitin sulfate on osteogenetic differentiation of human mesenchymal stem cells.

Chondroitin sulfate (CS) has anti-inflammatory properties and increases the regeneration ability of injured bone. In different in vivo investigations on bone defects the addition of CS to calcium phosphate bone cement has lead to an enhanced bone remodeling and increased new bone formation. The goal of this study was to evaluate the cellular effects of CS on human mesenchymal stem cells (hMSCs). In cell culture experiments hMSCs were incubated on calcium phosphate bone cements with and without CS and cultivated in a proliferation and an osteogenetic differentiation media. Alkaline phosphatase and the proliferation rate were determined on days 1, 7 and 14. Concerning the proliferation rates, no significant differences were detected. On days 1, 7 and 14 a significantly higher activity of alkaline phosphatase, an early marker of osteogenesis, was detected around CS modified cements in both types of media. The addition of CS leads to a significant increase of osteogenetic differentiation of hMSCs. To evaluate the influence of the osteoconductive potency of CS in twelve adult male Wistar rats, the interface reaction of cancellous bone to a nanocrystalline hydroxyapatite cement containing type I collagen (CDHA/Coll) without and with CS (CDHA/Coll/CS) was evaluated. Cylindrical implants were inserted press-fit into a defect of the tibial head. 28days after the operation the direct bone contact and the percentage of newly formed bone were significantly higher on CDHA/Coll/CS-implants (p<0.05). The addition of CS appears to enhance new bone formation on CDHA/Coll-composites in the early stages of bone healing. Possible mechanisms are discussed.

Surface modification of implants in long bone.

Coatings of orthopedic implants are investigated to improve the osteoinductive and osteoconductive properties of the implant surfaces and thus to enhance periimplant bone formation. By applying coatings that mimic the extracellular matrix a favorable environment for osteoblasts, osteoclasts and their progenitor cells is provided to promote early and strong fixation of implants. It is known that the early bone ongrowth increases primary implant fixation and reduces the risk of implant failure. This review presents an overview of coating titanium and hydroxyapatite implants with components of the extracellular matrix like collagen type I, chondroitin sulfate and RGD peptide in different small and large animal models. The influence of these components on cells, the inflammation process, new bone formation and bone/implant contact is summarized.

Foot and ankle fractures during childhood: review of the literature and scientific evidence for appropriate treatment / Fraturas do tornozelo e do pé na infância: revisão da literatura e evidências científicas para o tratamento adequado

ABSTRACT Foot and ankle fractures represent 12% of all pediatric fractures. Malleolar fractures are the most frequent injuries of the lower limbs. Hindfoot and midfoot fractures are rare, but inadequate treatment for these fractures may results in compartment syndrome, three-dimensional deformities, avascular necrosis and early post-traumatic arthritis, which have a significant impact on overall foot and ankle function. Therefore, the challenges in treating these injuries in children are to achieve adequate diagnosis and precise treatment, while avoiding complications. The objective of the treatment is to restore normal anatomy and the correct articular relationship between the bones in this region. Moreover, the treatment needs to be planned according to articular involvement, lower-limb alignment, ligament stability and age. This article provides a review on this topic and presents the scientific evidence for appropriate treatment of these lesions.

RESUMO As fraturas do tornozelo e do pé representam 12% de todas as fraturas pediátricas. Fraturas maleolares são as lesões mais frequentes dos membros inferiores; fraturas do retropé e mediopé são raras, mas o seu tratamento inadequado pode resultar em síndrome de compartimento, deformidades tridimensionais, necrose avascular e osteoartrose pós-traumática precoce, as quais apresentam impacto significativo na função global do tornozelo e pé. Portanto, os desafios no tratamento dessas lesões na criança são o diagnóstico adequado e tratamento preciso para se evitarem as complicações. O objetivo do tratamento é restaurar a anatomia normal e a relação articular correta entre os ossos da região. Além disso, o tratamento deve ser planejado de acordo com acometimento articular, o alinhamento dos membros inferiores, a estabilidade ligamentar e a idade. O algoritmo de tratamento dos traumas complexos do tornozelo e pé na infância é descrito. Este artigo apresenta uma revisão sobre o tema e as evidências científicas para o tratamento adequado dessas lesões.

Anatomic Reconstruction of Malunited Chopart Joint Injuries.

Fractures and dislocations at the mid-tarsal (Chopart) joint are frequently overlooked or misinterpreted at first presentation. Inadequate joint reduction and stabilization almost invariably lead to painful malunions or nonunions, residual instability, and deformity. Because of the central position and the essential function of the mid-tarsal joint, malunions lead to a considerable impairment of global foot function and the rapid development of posttraumatic arthritis. While secondary anatomical reconstruction with joint preservation would be desirable in order to restore normal foot function, it is amenable only if no symptomatic arthritis or avascular necrosis is present. Over a course of 6 years, eight patients have been treated with secondary correction, joint realignment, and internal fixation. In four of these cases, nonunions of the tarsal navicular were debrided and bone-grafted; in the remaining cases, a corrective osteotomy at the navicular or cuboid was carried out. At 2 years followup, all but one patient were satisfied with the result. One patient underwent fusion of the talonavicular joint for avascular necrosis and collapse of the navicular. The mean American Orthopaedic Foot and Ankle Score (AOFAS) improved significantly from 38.8 preoperatively to 80.8 at follow-up. However, the majority of malunited mid-tarsal fracture-dislocations will require corrective fusion of the affected joint(s) with axial realignment because of manifest posttraumatic arthritis at the time of patient presentation.

In vivo effects of modification of hydroxyapatite/collagen composites with and without chondroitin sulphate on bone remodeling in the sheep tibia.

The addition of chondroitin sulphate (CS) to bone cements with calcium phosphate has lead to an enhancement of bone remodeling and an increase in new bone formation in small animals. The goal of this study was to verify the effect of CS in bone cements in a large animal model simulating a clinically relevant situation of a segmental cortical defect of a critical size on bone-implant interaction and bone remodeling. The influence of adding CS to hydroxyapatite/collagen (HA/Col) composites on host response was assessed in a standard sheep tibia model. A midshaft defect of 3 cm was created in the tibiae of 14 adult female sheep. The defect was filled with a HA/Col cement cylinder in seven animals and with a CS-modified hydroxyapatite/collagen (HA/Col/CS) cement cylinder in seven animals. In all cases the tibia was stabilized with an interlocked universal tibial nail. The animals in each group were analyzed with X-rays, CT scans, histology, immunohistochemistry, and enzymehistochemistry, as well as histomorphometric measurements. The X-ray investigation showed a significantly earlier callus reaction around the HA/Col/CS implants compared to HA/Col alone. The amount of newly formed bone at the end point of the experiment was significantly larger around HA/Col/CS cylinders both in the CT scan and in the histomorphometric analysis. There were still TRAP-positive osteoclasts around the HA/Col implants after 3 months. The number of osteopontin-positive osteoblasts and the direct bone contact were significantly higher around HA/Col/CS implants. We conclude that addition of CS enhances bone remodeling and new bone formation around HA/Col composites.