Volume Manipulations for Simulating Bone and Joint Surgery

Bone and joint surgery is widely used in orthopedic, oral, and maxillofacial, and dental and plasty departments to correct bone and joint pathology such as bone and joint tumors and fractures, and skeletal morphological deformities. This article presents a voxel structure to represent topologically and geometrically correct surfaces and algorithms to accurately compute intersections of tool swept surfaces with bones based on this voxel structure. This article then presents various volume manipulation algorithms to operate on virtual bones, bone grafts, and prostheses for bone and joint surgery simulations. A complicated knee arthroplasty illustrates the practicality and versatility of the proposed method.

Current orthopaedic treatment of ballistic injuries

The purpose of this review is to examine current orthopaedic treatment of gunshot wounds. Surgeons are increasingly confronted by gunshot wounds that occur in both military and civilian settings. Much of the published work has been from military settings. In the United States, low-energy gunshot wounds are very common, and their incidence is increasing elsewhere in the world. Current treatment and its rationale is reviewed and a systematic approach to the assessment and treatment of these injuries is offered, taking into account the entirety of the injury, rather than simply the velocity of the missile.

Interventional radiology and the musculoskeletal system

Imaging-guided interventional procedures are becoming increasingly important in clinical rheumatology, since arthrocentesis of peripheral joints and the spine, as well as soft tissue injections, have a high rate of para-articular localisation when performed as blind techniques. Ultrasound-guided needle placement is the method of choice for interventional procedures on peripheral joints and for soft tissue injections. Fluoroscopy and computed tomography (CT) are not recommended for these indications due to the application of ionising radiation and the high procedural effort. By contrast, CT and magnetic resonance imaging are preferred for a variety of percutaneous procedures on the spine and sacroiliac joints. The increasing use of these methods for interventional purposes should improve both technical and procedural quality, thus ensuring cost-effectiveness and patient safety.

Unilateral congenital elbow luxation in a Cavalier King Charles Spaniel

A 7-week-old, intact female, Cavalier King Charles Spaniel was evaluated for nonweight bearing lameness of the right forelimb. Type III unilateral congenital elbow luxation was diagnosed radiographically. After surgical reduction, temporary placement of a transarticular pin, and external splinting of the joint, full weight bearing was achieved. Radial head subluxation persisted.

Disc arthroplasty: lessons learned from total joint arthroplasty

BACKGROUND CONTEXT

With the rapid emergence of new disc arthroplasty designs and ongoing clinical trials, there is great anticipation among clinicians. Inevitably there will be challenges associated with adoption of this new technology. Potential lessons learned from the extensive experience with extremity arthroplasty may predict some of the perils and pitfalls associated with motion-preserving devices in spinal applications.

PURPOSE

To review the extremity total joint literature for lessons that may be transferable to disc arthroplasty and anticipate predictable problems that will occur.

STUDY DESIGN/SETTING

A literature review and conjectural analysis of key lessons learned from the experience of extremity total joint arthroplasty and anterior lumbar interbody fusion devices with subsequent application of these lessons to disc arthroplasty in the lumbar spine.

METHODS

Limited data are available on disc arthroplasty.

RESULTS

Particular areas of controversy and uncertainty exist. The ongoing US Food and Drug Administration Investigational Device Exemption clinical trials may provide additional insight into these questions.

CONCLUSIONS

Complications will occur. These will be approach related, device related and patient-selection related. Studying the experience of extremity joint arthroplasty may accelerate the learning curve for lumbar disc arthroplasty.

Articular fractures

Although injuries to articular cartilage may lead to radiographic osteoarthritis, pain, and decreased joint function, the actual effects of such injury and of its treatment on joint function are not completely understood. The mechanisms of repair after impact loading are different from those after frank disruption by fracture of the articular cartilage, but basic and clinical research both indicate that the resultant articular surface is prone to degeneration. The sensitivity of a joint to resultant incongruity varies considerably, depending on the thickness and modulus of the articular cartilage and the geometry of the joint. Also, factors other than articular congruity play a substantial role in determining outcomes after treatment. For these reasons, defining a single threshold for articular displacement that correlates with outcomes in all joints is not practical. Some articular fractures injure cartilage so severely that the joint will degenerate even with an accurate articular reduction. Also, radiographic evidence of osteoarthritis does not necessarily correlate with poor function. More reliable measurement techniques are needed to accurately assess how treatment affects arthritis, and factors other than articular congruity are needed to predict posttraumatic arthritis.

Short-term BMP-2 expression is sufficient for in vivo osteochondral differentiation of mesenchymal stem cells

Currently available murine models to evaluate mesenchymal stem cell (MSC) differentiation are based on cell injection at ectopic sites such as muscle or skin. Due to the importance of environmental factors on the differentiation capacities of stem cells in vivo, we investigated whether the peculiar synovial/cartilaginous environment may influence the lineage specificity of bone morphogenetic protein (BMP)-2-engineered MSCs. To this aim, we used the C3H10T1/2-derived C9 MSCs that express BMP-2 under control of the doxycycline (Dox)-repressible promoter, Tet-Off, and showed in vitro, using the micropellet culture system that C9 MSCs kept their potential to differentiate toward chondrocytes. Implantation of C9 cells, either into the tibialis anterior muscles or into the joints of CB17-severe combined immunodeficient bg mice led to the formation of cartilage and bone filled with bone marrow as soon as day 10. However, no differentiation was observed after injection of naïve MSCs or C9 cells that were repressed to secrete BMP-2 by Dox addition. The BMP-2-induced differentiation of adult MSCs is thus independent of soluble factors present in the local environment of the synovial/cartilaginous tissues. Importantly, we demonstrated that a short-term expression of the BMP-2 growth factor is necessary and sufficient to irreversibly induce bone formation, suggesting that a stable genetic modification of MSCs is not required for stem cell-based bone/cartilage engineering.

Host protection against deliberate bacterial contamination of an extracellular matrix bioscaffold versus Dacron mesh in a dog model of orthopedic soft tissue repair

The resistance of two biomaterials, one synthetic and one biologic in origin, to deliberate bacterial infection was compared in a dog model of orthopedic soft tissue reconstruction. Twenty-four adult female dogs were randomly divided into two equal groups and a 2.0-cm-round full-thickness defect was created on the lateral surface of the stifle joint, leaving only the synovium and skin intact. The defect was surgically repaired with either Dacron trade mark mesh or a porcine derived extracellular matrix (ECM) scaffold material. The repair site was inoculated with 1 x 10(8) Staphylococcus aureus at the time of surgery and the dogs were survived for 28 days. Results showed a chronic pyogranulomatous inflammatory response at the Dacron trade mark implant sites versus a constructive tissue-remodeling response without residual inflammation at the ECM implant site. Three dogs in the group receiving the Dacron trade mark mesh were treated with Keflex trade mark (500 mg bid x 7 days) for signs of septicemia. A quantitative bacterial count of the implant sites at the time of sacrifice showed 6.52 x 10(5) +/- 1.2 x 10(6) and 6.5 x 10(2) +/- 1.8 x 10(3) bacteria per gram of tissue for the Dacron trade mark and ECM scaffold sites, respectively (P <.03). The ECM implant material was more resistant than the synthetic implant material to persistent infection following deliberate bacterial contamination and the ECM scaffold supported constructive tissue remodeling.

[Repairing porcine knee joint osteochondral defects at non-weight bearing area by autologous BMSC]

OBJECTIVE

To test the possibility of using bone marrow stromal cells (BMSC) and biodegradable polymers to repair articular osteochondral defects at non-weight bearing area of porcine knee joints.

METHODS

Bone marrows were harvested from 18 hybrid pigs. BMSC were cultured and in vitro expanded and induced with dexamethasone (group A) or with dexamethasone and transforming growth factor-beta1 (TGF-beta1) (group B) respectively. Immunohistochemistry and RT-PCR were used to evaluate chondrogenic differentiation of induced cells. Part of BMSC of 2 animals were retrovirally-labeled with green fluorescent protein (GFP). After induction and label, cells were seeded on a construct of polyglycolic acid (PGA) and polylactic acid (PLA) and co-cultured for 1 week before implantation. Total 4 osteochondral defects (8 mm in diameter, 5 mm in depth) in each animal were created at the non-weight bearing areas of knee joints on both sides. The defects were repaired with dexamethasone induced BMSC-PGA/PLA construct in group A, with dexamethasone and TGF-beta1 induced BMSC-PGA/PLA construct in group B, with PGA/PLA construct alone (group C) or left untreated (group D) as controls. Animals were sacrificed at 3 months (n = 6) or 6 months (n = 10) post-repair. Gross observation, histology, glycosaminoglycan (GAG) quantification and biomechanical test were applied to analyze the results. The two animals with GFP-labeled cells were sacrificed at 7 months post-repair to observe with confocal microscope the distribution of GFP-labeled cells in repaired tissue.

RESULTS

Stronger expression of type II collagen and aggrecan were observed in BMSCs induced with both dexamethasone and TGF-beta1. At both time points, Gross observation and histology showed that the defects in most of group A were repaired by engineered fibrocartilage and cancellous bone with an irregular surface, minority defects were repaired by engineered hyaline cartilage and cancellous bone. However, in most of group B, the defects were completely repaired by engineered hyaline cartilage and cancellous bone. No repair or only fibrous tissue were observed in groups C and D. Besides, the compressive moduli of repaired cartilage in groups A and B reached 30.37% and 43.82% of normal amount at 3 months and 62.69% and 80.27% at 6 months respectively, which was further supported by the high levels of GAG contents in engineered cartilage of group A (78.03% of normal contents) and group B (no statistical difference from normal contents). More importantly, confocal microscope revealed the presence of GFP-labeled cells in engineered cartilage lacuna and repaired underlying cancellous bone.

CONCLUSION

The results demonstrated that implanted BMSC can differentiate into either chondrocytes or osteoblasts at different local environments and repair a complex articular defect with both engineered cartilage and bone. TGF-beta1 and dexamethasone in vitro induction can promote chondrogenic differentiation of BMSC and thus improve the results of repairing articular defects.

Trends in utilization: has extremity MR imaging replaced diagnostic arthroscopy?

OBJECTIVE

To examine the relative change in utilization of magnetic resonance (MR) imaging of the extremities versus diagnostic and therapeutic arthroscopy.

DESIGN AND PATIENTS

Using the 1993, 1996, and 1999 nationwide Medicare Part B databases, utilization rates (per 100000) were determined for upper and lower extremity MR imaging, diagnostic arthroscopy and therapeutic arthroscopy using CPT-4 codes. Utilization of extremity MR imaging was compared with that of diagnostic and therapeutic arthroscopy in 10 geographic regions of the United States and tracked over time.

RESULTS

Combined lower and upper extremity MR imaging utilization per 100000 increased from 393 to 1056 in 1999 (+168.7%). Utilization of diagnostic arthroscopy of the extremities decreased from 18 in 1993 to 8 in 1999 (-55.6%); therapeutic arthroscopy rates increased from 461 in 1993 to 636 in 1999 (+40.0%). Specifically, from 1993 to 1999, utilization of lower extremity MR imaging increased from 270 to 661 (+144.8%). Utilization of diagnostic arthroscopy of the knee over the same time period decreased from 11 to 5 (-54.5%); therapeutic arthroscopy increased from 394 to 501 (+27.2%). Similarly, utilization rates for upper extremity MR imaging increased from 123 to 395 (+221.1%). Utilization of diagnostic arthroscopy of the shoulder over the same time period decreased from 7 to 2 (-71.4%); therapeutic arthroscopy increased from 44 to 104 (+136.4%). No specific geographic trends were ascertained.

CONCLUSION

The utilization of MR imaging of the extremities has markedly increased from 1993 to 1999. During the same time period the utilization of diagnostic arthroscopy has decreased and that of therapeutic arthroscopy has increased. These findings support the hypothesis that there is increased reliance of clinical practitioners on the diagnostic information provided by MR imaging in preoperative clinical decision-making.

Mechanical interface conditions affect morphology and cellular activity of sclerotic bone rims forming around experimental loaded implants

A characteristic bony structure found at revision surgery for failed joint replacement, and implicated as being associated with poorer subsequent implant fixation, is a sclerotic bone rim (SB rim). This study is a histomorphometric analysis of the SB rim formed around an experimental canine micro-motion implant system under stable or unstable conditions with polyethylene (PE) particles, after 8 weeks. A point count histomorphometric analysis was performed to determine the cellular activity at the surface of the SB rim, and the morphology of the structure was determined by image analysis. A SB rim was found to form under both stable and unstable conditions, but with unstable conditions the rim was more distinct, thick, continuous, and was located near the drill hole, and had high and ongoing formative activity at both surfaces with little resorption. Under stable conditions, thinner second or third SB rims were observed. The difference in width and distance between implant and the SB rim is significant (p<0.05), as was the difference in fraction of resorption surfaces at the SB surface facing the implant. This study observed an in vivo primary bone response to controlled stable and unstable loaded implants. Sclerosis of trabeculae in a semi-continuous SB rim can serve to isolate the implant from the marrow space. The increases in SB rim width and continuity is consistent with the previously demonstrated knowledge that increase of total bone mass and low risk for trabeculae perforation is the consequence of low resorptive and high formative activity.

Intraarticular osteoid osteoma: clinical features, imaging results, and comparison with extraarticular localization

OBJECTIVE

Intraarticular osteoid osteoma is uncommon and presents diagnostic difficulties, which are important for both rheumatologists and orthopedic surgeons. Clinical symptoms, imaging procedures, differential diagnostic problems, and treatment results of intraarticular as compared with extraarticular osteoma are analyzed in this retrospective study.

METHODS

Nineteen patients with intraarticular osteoid osteomas (Group A), with a mean followup period of 34 months, are compared with 15 others with extraarticular lesions (Group B).

RESULTS

Nine intraarticular tumors were located in the hip, 3 in the elbow, 6 in the ankle, and one in the first metatarsal head. The nonspecific symptoms in Group A, such as chronic synovitis, decreased range of motion, joint effusion, contractures, and lack of the intense perifocal sclerotic margin on radiographs, led to significant delay in diagnosis (on average 26.6 mo in Group A, 8.5 mo in Group B). The extreme variety of previous diagnoses at referral reflect the problems of differential diagnosis. A detectable nidus is often absent on conventional radiograph. Bone scintigraphy is unspecific and often fails to visualize the nidus. Computed tomography scans were accurate in two-thirds of the intraarticular and in 90% of extraarticular cases. Magnetic resonance image findings, although sometimes controversial, provided essential additional information for the correct diagnosis and therapy.

CONCLUSION

Clinical symptoms and imaging signs of intraarticular osteoid osteomas were significantly different from the classical hallmarks of extraarticular lesions. The 10% intraarticular occurrence of osteoid osteomas in this series is not as rare as some investigators suggest. The radiological and clinical findings are uncharacteristic and misleading, and the lesions are difficult to identify. Careful search for history data, such as nocturnal pain and positive salicylate test, in addition to extensive imaging procedures, led to the correct diagnosis prior to surgery in two-thirds of our patients with intraarticular osteoid osteomas.

In vivo comparison of a metal versus a biodegradable suture anchor

PURPOSE

This protocol compares an absorbable polylactic acid (PLA) anchor to a similarly sized metallic anchor, comparing the load to failure of the suture anchor construct in vivo in a goat model.

TYPE OF STUDY

Basic science.

METHODS

Thirty-nine goats underwent bilateral implantation of suture anchors at the intra-articular origin of the long digital extensor tendon at the knee (stifle). Each goat randomly received an absorbable anchor in one knee and a metallic anchor in the other. At 0, 6, and 12 weeks after implantation, the suture attached to the implanted anchor was pulled to failure on a materials testing machine, annotating the load at failure and location of failure of the suture anchor construct.

RESULTS

At each time period tested, no difference was found in failure load between metal and PLA suture anchor constructs, nor was there degradation in strength over time of implantation of either anchor. Most failures occurred by suture breakage, and the force required for suture breakage did not differ between anchors. Three absorbable PLA anchors failed, one (1 of 13, 7.7%) at 6 weeks, and 2 (15.4%) at 12 weeks. PLA anchor failure occurred when the suture loop eyelet pulled out of the anchor's PLA body.

CONCLUSIONS

The absorbable PLA suture anchor construct, tested in an in vivo, intra-articular model, had similar strength over a 12-week period of implantation with a comparable metal anchor construct. These absorbable anchors offer a reasonable alternative to metal anchors, with comparable strength and function and advantages unique to an absorbable anchor.

CLINICAL RELEVANCE

This study provides the reader with an evaluation of the in vivo function and holding strength over time of implantation of an absorbable suture anchor in comparison with a metal anchor.

Legionella pneumophila serogroup 4 isolated from joint tissue

We report the isolation of Legionella pneumophila serogroup 4 from synovial tissue obtained from an 80-year-old female with chronic swelling of her right metacarpophalangeal joint. Synovial tissue infections caused by L. pneumophila are rare. Interestingly, this isolate was recovered from chocolate agar after 5 days of incubation.

[The advanced technology of three-dimensional medical imaging in spine, bone and joints]

The advanced technology of three-dimensional (3-D) medical imaging allows us to understand the patient specific anatomy in detail. Especially, in orthopedic surgery, treated spinal diseases or the disorders of bone and joints, the 3-D computed tomography(CT), such as multi-slice CT and helical CT is a useful tool for clinical diagnosis and surgical treatment. Since 1995, by the use of these 3-D CT image data, computer navigation system and surgical robot were developed and applied to a spinal instrumentation surgery and an artificial joint replacement. Now surgeons can perform the precise and safe surgical procedure by the computer guidance on the base of 3-D medical imaging.

Long-term results of multiple synovectomy for patients with refractory rheumatoid arthritis. Effects on disease activity and radiological progression

OBJECTIVES

We developed a radical multiple synovectomy (RaMS) procedure designed to reduce disease activity in refractory RA patients involving the excision of all inflamed synovial tissues. In this study we examined the long-term outcome of RaMS in terms of disease activity and articular destruction.

METHODS

Forty-two patients with refractory RA underwent RaMS and were followed up for an average of 7.3 years. Clinical findings and radiological outcome were evaluated and compared to a control group.

RESULTS

More than 40% of patients continued to maintain improvement up to 4 years after the operation. The number of swollen joints and painful joints, the erythrocyte sedimentation rate, CRP and rheumatoid factor quickly decreased after the operation. The beneficial effects continued for 4 years compared to patients treated with combination disease modifying anti-rheumatic drug therapy. The damage score worsened less rapidly in patients undergoing RaMS than in the control group. Articular destruction was less marked in the PIP, MP, wrist and ankle joints of patients who responded well to RaMS.

CONCLUSIONS

RaMS was effective for refractory RA in the short term and seemed to offer some advantages over other therapies in terms of slowing articular destruction. However, RaMS did not radically alter the natural disease course of RA.

The effect of graft height mismatch on contact pressure following osteochondral grafting: a biomechanical study

HYPOTHESIS

Incongruity of the articular cartilage following osteochondral transplantation affects surface contact pressure.

STUDY DESIGN

An 80 N load was applied for 120 seconds to the femoral condyles of 10 swine knees. Contact pressures were measured using Fuji prescale film. Seven conditions were tested: (1) intact articular surface; (2) 4.5-mm diameter defect; (3) grafted with 4.5-mm diameter plug elevated 1 mm above adjacent cartilage; (4) plug elevated 0.5 mm; (5) plug flush; (6) plug sunk 0.5 mm below surface; and (7) sunk 1.0 mm.

CONCLUSIONS

Peak contact pressures were significantly (P <.001) elevated by approximately 20% after defect creation and were reduced to normal when plugs were flush. There were large and significant (P<.001) increases in pressure with plugs elevated 1 and 0.5 mm. Contact pressures with plugs sunk 0.5 and 1 mm were significantly (P <.01) higher than intact cartilage but were significantly (P <.01) lower than an empty defect.

CLINICAL RELEVANCE

Normal contact pressures and patterns can be duplicated with flush articular surface grafts. However, small incongruities, particularly when the plug is elevated, can lead to significantly increased pressure. This reinforces the importance of articular surface congruity in the initial biomechanical state following osteochondral implantation.

Biomechanical and histological evaluation of osteochondral transplantation in a rabbit model

BACKGROUND

Biomechanical and histological properties of osteochondral transplantation have not been extensively examined.

HYPOTHESIS

Osteochondral grafts have properties similar to native articular cartilage.

STUDY DESIGN

Controlled laboratory study.

METHODS

A 2.7 mm (diameter) x 4.0 mm (depth) osteochondral defect was created in 17 New Zealand white rabbit knees. An osteochondral graft, harvested from the contralateral knee, was transplanted into the defect. Eight rabbits were sacrificed each at 6 and 8 weeks.

RESULTS

The 12-week grafts (1213.6 +/- 309.0 N/mm) had significantly higher stiffness than the 6-week grafts (483.1 +/- 229.1 N/mm; P <.001) and of normal cartilage (774.8 +/- 117.1 N/mm; P <.003). Stiffness of the 6-week grafts was significantly lower than normal cartilage (P <.036). At all time points, full-thickness defects had significantly lower stiffness than normal cartilage (P <.001). Histologically, transplanted grafts scored significantly higher than the full-thickness defects (P <.001). The defects showed inconsistent, fibrocartilage healing. The grafts demonstrated cartilage viability, yet with a persistent cleft between the graft and host.

CONCLUSIONS

Osteochondral transplants undergo increased stiffness in the short term, with evidence of structurally intact grafts.

CLINICAL RELEVANCE

Osteochondral transplantation may be a viable treatment option; however, long-term investigation on graft function is necessary.

Surveillance Venous Duplex Is Not Clinically Useful after Total Joint Arthroplasty When Effective Deep Venous Thrombosis Prophylaxis Is Used

The early detection of deep venous thrombosis (DVT) and treatment with systemic anticoagulation to prevent pulmonary embolism (PE) are essential in the management of patients undergoing total joint arthroplasty (TJA). However, improvements in prophylactic measures have significantly decreased the occurrence of DVT in these patients. The purpose of this study was to determine whether routine postoperative duplex surveillance for DVT remains clinically useful. The medical records of all patients undergoing total knee or total hip arthroplasty between October 1997 and January 2002 at a University Hospital and its Veterans Affairs (VA) affiliate were reviewed. The type of operation and occurrence of complications (e.g., DVT, PE, and hemorrhage) were noted. All patients were treated postoperatively with both enoxaparin 30 mg b.i.d. and bilateral lower extremity sequential compression devices (SCDs). A venous duplex scan was performed prior to discharge. Three hundred ninety-eight patients underwent 441 TJAs for 149 hips and 292 knees. The average age was 65 years (range, 23-95). Venous duplex scans were performed within 1 week (median, 4 days) of operation. Initial inpatient scans revealed acute, ipsilateral DVT in five patients (1.3%). Three patients experienced documented PE-one as an inpatient and two after hospital discharge; both outpatients had negative inhospital duplex scans. One of the 398 patients did not have a duplex scan as an inpatient and returned 6 weeks later with a popliteal DVT. Complications included one upper gastrointestinal hemorrhage, and one patient died postoperatively of unknown causes. These data demonstrate that routine postoperative venous duplex scans rarely found DVT (5 of 398 patients) after TJA when effective prophylaxis was used. Furthermore, surveillance scanning did not enable reliable prediction of PE. Therefore, we conclude that postoperative inpatient surveillance duplex scans for DVT provide very minimal benefit and that a routine screening program is not clinically useful for patients managed with effective DVT prophylaxis.

[Experimental study of bone morphogenetic protein-2 in noncemented fixation of prosthesis]

OBJECTIVE

To study on the method of combining rhBMP(2) with porous-coated implants, and compared the histological and biomechanical results of 4 types of implants by being inserted into the femur of canine.

METHODS

4 types of implants which are porous-coated implants (PCA), PCA implants combined with BMP, PCA implants coated with hydroxyapatite and HA coated cylindrical implants had been inserted into the femur of 16 canines. After 4, 8, 12 and 24 weeks the femur of the canines with the implants were retrieved. Bone ingrowth and shear strength of the interface was studied and analysed by the means of X-ray, soft X-ray, fluorescence tag, non-decalcification bone ground section, computer-aided image analysis procedure and biomechanical test.

RESULTS

X-ray, soft X-ray, fluorescence tag, non-decalcification bone ground section and computer-aided image analysis procedure was used in histological study, and it showed that bony ingrowth into interface more than the other groups, even the maturation of newly formed bone. Non-decalcification bone ground section observation and computer aided image analysis showed the results: the new bone formation ratio of BMP group was 26.58% +/- 4.56% at 4 weeks post-implantation, which was much higher than the other groups, and there was significant difference between BMP group and each of the other group statistically (P < 0.05). Results of biomechanical study using push-out test showed that shear strength of each group appeared to rise with time. Shear strength of BMP group reached a high level at 4 weeks which was 18.94 +/- 5.11Mpa and almost twice of the other group, and there was also statistical difference between BMP group and each of the other group (P < 0.05). And the new bone formation ratio and shear strength of BMP group at 8, 12, 24 weeks post-implantation was still higher than the other group, but there was no statistically difference.

CONCLUSIONS

Porous-coated implants combined with rhBMP can enhance bone ingrowth at bone-implant interface especially at the early period post-implantation. Porous-coated implants combined with rhBMP(2) can not only shorten the time of new bone formation and bone ingrowth but also enhance shear strength of bone-implant interface.

[Endoprosthesis of great joints of extremities in difficult anatomic conditions]

Experience in endoprosthesis of great joints in 408 patients in difficult clinical cases associated with defects and deformations of bones of posttraumatic, oncological, dysplastic and systemic character, and also in the cases of complications after primary endoprosthesis is analyzed. Special constructions of implants, instruments, surgical technique were used depending on anatomic and functional changes. Results of endoprosthesis of great joints were accessed as successful in 95% patients in maximal period of follow-up during 13 years.

[Clinical views on simulation and navigation technologies in kinematics of joints in locomotor surgery]

In this paper the authors give an overview of two systems (simulation and navigation) which are very important and give support to clinical work by making possible good visualization of the morphology and kinematics of joints. The approach to each patient with changes in the joints is individualized with a computer generated tomographical images which give very precise data which up to now had been inaccessible with clinical testing as the only alternative was the well known invasive diagnostic procedures. The first case concerns the COJOKS simulation system (COmputerized Joint Kinematics Simulation). The second case is of a navigation operative system which has recently been put into use and was developed on the basis of the GPS system (MSNT). This system is used for the precise determination of the bone structure of joints which is, by way of computer transformed into virtual 3D shape. This gives the surgeon all the data necessary during the operative procedure on bone and joint structures.

[Osseous-perichondral autoplasty in surgery for tuberculosis of the joints]

The results of 68 reconstruction surgeries made in the hip and knee joints in tuberculosis and concomitant diseases were studied. Advantages of operations involving the component plasty of joint ends (osseous autoplasty, as well as auto-perichondral plasty and their variations), including under the conditions of revascularization of the osseous bed, were proven on the basis of the results of a comparative analysis of clinical-and-functional data and X-ray examinations. The use of the method ensuring additional sources for vascularizing the joint tissues improves the conditions of autograft assimilation; the application of perichondral grafting preserves or expands the joint split, which provides an increased mobility amplitude in a damaged joint. The use of perichondral plasty and of its combination with revascularization of the joint osseous joint tissues secured more favorable results as compared to the implementation of osseous-plasty interventions alone.

Peroneal intraneural ganglia: the importance of the articular branch. A unifying theory

OBJECT

Based on a large multicenter experience and a review of the literature, the authors propose a unifying theory to explain an articular origin of peroneal intraneural ganglia. They believe that this unifying theory explains certain intriguing, but poorly understood findings in the literature, including the proximity of the cyst to the joint, the unusual preferential deep peroneal nerve (DPN) deficit, the absence of a pure superficial peroneal nerve (SPN) involvement, the finding of a pedicle in 40% of cases, and the high (10-20%) recurrence rate.

METHODS

The authors believe that peroneal intraneural lesions are derived from the superior tibiofibular joint and communicate from it via a one-way valve. Given access to the articular branch, the cyst typically dissects proximally by the path of least resistance within the epineurium and up the DPN and the DPN component of the common peroneal nerve (CPN) before compressing nearby SPN fascicles. The authors present objective evidence based on anatomical, clinical, imaging, operative, and histological data that support this unifying theory.

CONCLUSIONS

The predictable clinical presentation, electrical studies, imaging characteristics, operative observations, and histological findings regarding peroneal intraneural ganglia can be understood in terms of their origin from the superior tibiofibular joint, the anatomy of the articular branch, and the internal topography of the peroneal nerve that the cyst invades. Understanding the controversial pathogenesis of these cysts will enable surgeons to perform operations based on the pathoanatomy of the articular branch of the CPN and the superior tibiofibular joint, which will ultimately improve clinical results.

Theoretical investigation of an artificial joint with micro-pocket-covered component and biphasic cartilage on the opposite articulating surface

This paper presents a theoretical investigation of a geometrically idealized artificial joint with micro-pocket-covered component and biphasic cartilage on the opposite articulating surface. The fluid that exudes from the biphasic cartilage fills and pressurizes the micro-pockets. In this way, a poro-elasto-hydrodynamic regime of lubrication is developed. Assuming that lower friction would result in lower adhesive wear, and neglecting the fatigue as well as the abrasive wear, the proposed bearing system hypothetically could reduce the amount of wear debris. Equations of the linear biphasic theory are applied for the confined and unconfined compression of the cartilage. The fluid pressure and the elastic deformation of the biphasic cartilage are explicitly presented. The effective and equilibrium friction coefficients are obtained for the particular configuration of this bearing system. The micro-pockets geometrical parameters (depth, radius, surface distribution and edge radius) must be established to reduce the local contact stresses, to assure low friction forces and to minimize the biphasic cartilage damage. The influence of the applied pressure, porosity of the micro-pocket-covered component, filling time, cartilage elasticity, permeability and porosity upon the micro-pockets depth is illustrated. Our results are based upon the previously published data for a biphasic cartilage.

Peroneal intraneural ganglia: the importance of the articular branch. Clinical series

OBJECT

The peroneal nerve is the most common site of intraneural ganglia. The neurological deficit associated with these cysts is often severe and the operation to eradicate them is difficult The aims of this multicenter study were to collate the authors' experience with a relatively rare lesion and to improve clinical outcomes by better understanding its controversial pathogenesis.

METHODS

Part I of this paper offers a description of 24 patients with peroneal intraneural ganglia who were treated by surgeons aware of the importance of the peroneal nerve's articular branch. Part II offers a description of three more patients who were seen after earlier operations in which the ganglion was excised, but the articular branch was not identified (all reportedly gross-total resections). Twenty-six of the 27 patients presented with clinical electrophysiological, and imaging evidence of a common peroneal nerve (CPN) lesion, predominantly affecting the deep peroneal nerve (DPN) division, and one patient presented with a painful mass of the CPN that was not accompanied by a neurological deficit. In all 24 patients in Part I there was magnetic resonance (MR) imaging evidence of a connection between the cyst and the superior tibiofibular joint, including one patient in whom high-resolution (3-tesla) MR neurography demonstrated the pathological articular branch itself. At the operation, the communication proved to extend through the articular branch of the CPN in all cases. The operation consisted of drainage of the cyst and ligation of the articular branch. At a minimum follow-up period of 1 year, these patients experienced significant improvements in their neuropathic pain, but only mild improvements in their functional deficits. In none of the 24 patients was there evidence of an intraneural recurrence. In three patients, however, extraneural ganglia developed: two patients with symptoms subsequently underwent resection of the superior tibiofibular joint without further recurrence and one patient with no symptoms was followed clinically after the recurrence was detected incidentally on 1-year postoperative imaging. As predicted, in Part II all three patients in whom the articular branch had not been ligated experienced early intraneural recurrence; both postoperative MR images and original studies, which were retrospectively examined, demonstrated a connection with the superior tibiofibular joint.

CONCLUSIONS

The clinical presentation, electrical studies, imaging characteristics, and operative observations regarding peroneal intraneural ganglia are predictable. Treatment must address the underlying pathoanatomy and should include decompression of the cyst and ligation of the articular branch of the nerve. To avoid extraneural recurrence, resection of the superior tibiofibular joint may also be necessary, but indications for this additional procedure need to be defined. These recommendations are based on the authors' belief that intraneural peroneal ganglia arise from the superior tibiofibular joint and are connected to it by the articular branch.

Intramedullary transmetatarsal Kirschner wire fixation of Lisfranc fracture-dislocations

Lisfranc joint injuries are frequently the result of high-energy accidents. The usual method of treatment is open reduction and internal fixation or closed reduction with percutaneous pinning. In cases in which soft tissue injury may compromise open reduction and internal fixation or traditional pinning techniques, transmetatarsal Kirschner wire fixation may be performed, allowing the placement of temporary hardware away from the site of soft tissue injury. The following report details this technique as it has been used in 3 patients.

Lavage of contaminated surfaces: an in vitro evaluation of the effectiveness of different systems

INTRODUCTION

Lavage is an effective, additive therapeutic procedure with a broad application in surgery. In addition to irrigation with the conventional syringe, the pulsed jet lavage system is used. The effectiveness of bacterial reduction depends on, among other things, the irrigation pressure. Complications of high-irrigation pressure in bone and joint surgery are intramedullary seeding of bacteria, visible damage of the bone, or delayed healing of the fracture by lavage of the fracture zone. The purpose of this in vitro study was to evaluate the effectiveness of mechanical irrigation on several surfaces using different systems of irrigation.

MATERIALS AND METHODS

Four different test surfaces (nonbiological surfaces: sterilized bone cement and titanium osteosynthesis plates; biological surfaces: gamma-irradiated bovine muscle and cancellous bone) were contaminated with a defined suspension of different bacterial species (Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa). The samples were irrigated with three different systems (conventional 50-ml plastic syringe, manual pump irrigator, jet lavage) in a standardized, randomized experimental setup. After irrigation of the sample the amount of residual bacteria (colony-forming units) was determined.

RESULTS

An effective bacterial reduction was achieved with the use of irrigation regardless of the system that was used and surface that was cleaned. On average P. aeruginosa was reduced around log 1.907, E. faecalis around log 1.666 and S. aureus around log 1.506. On biological surfaces, a reduction around log 0.801 for muscle and around log 1.738 for bone samples was achieved independent of the system that was used for irrigation. For the titanium surface a reduction of log 1.652 compared with log 2.580 for the bone cement surface was demonstrated. Statistical analysis showed that mechanical lavage resulted in a significant reduction of all tested bacterial species on the surfaces. The best bacterial reduction was achieved with the manual pump irrigator (P = 0.06). The results demonstrate that the manual pump irrigator achieved significantly better bacterial reduction (P = 0.039) on "biological surfaces" (bone and muscle) compared with nonbiological surfaces (titanium and cement).

CONCLUSION

The results show that irrigation is an effective technique for bacterial reduction on contaminated surfaces. A remarkable finding was the limited bacterial reduction of Staphylococcus aureus from gamma-sterilized muscle. The use of a continuous manual pump irrigator showed a greater reduction of bacteria contamination compared with the other means of irrigation investigated. In conclusion, the manual continuous irrigation system proved to be practical, economical and effective in reducing the bacterial load on various surfaces.

Autologous osteochondral mosaicplasty for the treatment of full-thickness defects of weight-bearing joints: ten years of experimental and clinical experience

BACKGROUND

The successful treatment of chondral and osteochondral defects of the weight-bearing surfaces is a challenge for orthopaedic surgeons. Autologous osteochondral transplantation is one method that can be used to create hyaline or hyaline-like repair in the defect area. This paper describes the results after ten years of clinical experience with autologous osteochondral mosaicplasty.

METHODS

Clinical scores, imaging techniques, arthroscopy, histological examination of biopsy samples, and cartilage stiffness measurements were used to evaluate the clinical outcomes and quality of the transplanted cartilage in 831 patients undergoing mosaicplasty.

RESULTS

According to these investigations, good-to-excellent results were achieved in 92% of the patients treated with femoral condylar implantations, 87% of those treated with tibial resurfacing, 79% of those treated with patellar and/or trochlear mosaicplasties, and 94% of those treated with talar procedures. Long-term donor-site disturbances, assessed with use of the Bandi score, showed that patients had 3% morbidity after mosaicplasty. Sixty-nine of eighty-three patients who were followed arthroscopically showed congruent gliding surfaces, histological evidence of the survival of the transplanted hyaline cartilage, and fibrocartilage filling of the donor sites. Complications of the surgery included four deep infections and thirty-six painful postoperative hemarthroses.

CONCLUSIONS

On the basis of these promising results and those of other similar studies, autologous osteochondral mosaicplasty appears to be an alternative for the treatment of small and medium-sized focal chondral and osteochondral defects of the weight-bearing surfaces of the knee and other weight-bearing synovial joints.

Declining use of orthopedic surgery in patients with rheumatoid arthritis? Results of a long-term, population-based assessment

OBJECTIVE

To describe the use of orthopedic surgery, including joint replacement surgery, in a well-defined, population-based cohort of patients with rheumatoid arthritis (RA) and to identify characteristics that predict such use.

METHODS

A retrospective medical record review was performed of cases of RA incident in Rochester, Minnesota, during the years 1955-1995. All joint surgeries were recorded.

RESULTS

Of the total 609 RA incident cases, 242 patients underwent 1 or more (maximum of 20/patient) surgical procedures involving joints during their followup. Overall, this RA cohort had 7.4 surgeries per 100 person-years of followup; the cumulative incidence for joint surgery for RA-related joint disease at 30 years was 33.7% +/- SEM 3.8%. The risk of having a disease-related joint surgery for RA is increased in patients who are women, younger, positive for rheumatoid factor, and have rheumatoid nodules. When adjusted for duration of followup, patients with RA diagnosed after 1985 were significantly less likely to have undergone joint surgery for RA (P < 0.001). Survival of patients who underwent total joint arthroplasty was similar to those who did not.

CONCLUSION

Reconstructive surgeries are common in RA, although patients diagnosed after 1985 are less likely to require joint surgery. These findings may reflect trends in medical disease management and have importance for health care resource utilization planning.

A comparison of joint stability between anterior cruciate intact and deficient knees: a new canine model of anterior cruciate ligament disruption

Transection of the canine anterior cruciate ligament (ACL) is a well-established osteoarthritis (OA) model. This study evaluated a new method of canine ACL disruption as well as canine knee joint laxity and joint capsule (JC) contribution to joint stability at two time points (16 and 26 weeks) after ACL disruption (n=5/time interval). Ten crossbreed hounds were evaluated with force plate gait analysis and radiographs at intervals up to 34 weeks after monopolar radiofrequency energy (MRFE) treatment of one randomly selected ACL. Each contralateral ACL was sham treated. The MRFE treated ACLs ruptured approximately eight weeks (mean 52.5 days, SEM+/-1.0, range 48-56 days) after treatment. Gait analysis and radiographic changes were consistent with established canine ACL transection models of OA. Anterior-posterior (AP) translation and medial-lateral (ML) rotation were measured in each knee at 30 degrees, 60 degrees, and 90 degrees of flexion with and then without JC with loads of 40 N in AP translation and 4 Nm in ML rotation. A statistically significant interaction in AP translation included JC by cruciate (P=0.02), and there was a trend for a cruciate by time (P=0.07) interaction. Significant interactions in ML rotational testing included the presence of joint capsule (P=0.0001) and angle by cruciate (P=0.0012). This study describes a model in which canine ACLs predictably rupture approximately eight weeks after arthroscopic surgery and details the contribution of JC to canine knee stability in both ACL intact and deficient knees. The model presented here avoids the introduction of potential surgical variables at the time of ACL rupture and may contribute to studies of OA pathogenesis and inhibition. This model may also be useful for insight into the pathologic changes that occur in the knee as the ACL undergoes degeneration prior to rupture.

Efficacy of contained metaphyseal and periarticular defects treated with two different demineralized bone matrix allografts

The efficacies of two different allografts, Grafton (demineralized bone matrix [DBM] in a glycerol carrier) and Orthoblast (DBM in a reverse thermal poloxamer carrier) were examined from cases involving periarticular fractures. Demographic, perioperative, and outcome data for patients with periarticular fractures who underwent a prospectively designed protocol for bone grafting were compiled, with 15 cases using Orthoblast and 13 using Grafton. A successful graft was defined as healing on the first graft attempt without complications. Healing was determined by radiographic studies and clinical evaluation. The successful graft rates of Orthoblast and Grafton were 15/15 and 9/13, respectively.

Joint irrigation as treatment for osteoarthritis

Irrigation is necessary to achieve distension and visualization of the joint during arthroscopy. Clinical improvement observed after diagnostic arthroscopy has been attributed to irrigation, and this is supported by sound pathophysiologic rationales. Studies have been performed using various irrigation techniques with and without concomitant arthroscopy. Unblinded studies have generally yielded favorable results, although recent blinded studies have demonstrated a substantial and durable placebo effect, but little support for the benefit of the irrigation procedure.

[Prophylaxis of pyogenic complications in total replacement of large joints]

Results are studied of management of 378 patients having undergone total knee and hip arthroplasty over the period 1995-2001. Surgical interventions were undertaken in those patients presenting with osteoarthrosis deformans, rheumatoid arthritis, for complicated posttraumatic fractures, pathological fractures secondary to an oncological process. Pyo-inflammatory complications which necessitated removal of endoprothesis developed in nine (2.32%) patients. A strict keeping to the system of the purulent complications prophylaxis in total arthroplasty is an important component of a successful management of those patients presenting with grave forms of affections of the great joints.

Gene marking in adeno-associated virus vector infected periosteum derived cells for cartilage repair

OBJECTIVE

To evaluate both the potential for transferring genes to periosteal cells using an adeno-associated virus (AAV) vector and the potential for gene expression after transplantation of those cells to a cartilage defect in vivo.

METHODS

Periosteum was obtained from the tibia of 6-week-old rabbits and enzymatically digested. The isolated periosteum derived cells were cultured and the subconfluence cells were infected with a recombinant AAV expressing the LacZ gene (AAV-LacZ). Collagen gel containing the LacZ transferred, periosteum derived cells was transplanted into a full thickness articular cartilage defect in 10 rabbits.

RESULTS

Infected cells still growing on the plate continued to express LacZ at least 12 weeks after AAV infection, with the highest percentage of LacZ positive cells reaching 74.4%. The LacZ positive cells were recognized at the transplant sites in 8 out of 10 knees.

CONCLUSION

Gene expression in periosteum derived cells was sustained in vitro for at least 12 weeks using the AAV vector, and for 2 weeks ex vivo after transplantation into a cartilage defect.

Rheumatological management of patients with hemophilia. Part 1: joint manifestations

The advent of factor VIII and IX replacement therapy has radically changed the physiognomy of hemophilia. In patients with no inhibitors, early replacement therapy shortens the immobilization and decreases the structural and functional alterations related to recurrent hemarthrosis. Routine prophylactic replacement therapy before or after the first episode of hemarthrosis is still rarely used in France. Recurrent hemarthrosis in the same joint can cause synovitis and chronic arthropathy. Injection synovectomy is now the preferred treatment, as opposed to secondary prophylactic replacement therapy and to arthroscopic or open synovectomy. The palliative treatment of chronic arthropathy is difficult and rests on analgesics and rehabilitation therapy, with orthotic devices and/or surgery where appropriate. The treatment of hemophilia is far more difficult in patients with inhibitors and, consequently, considerable hope is being placed in gene therapy, whose first results are encouraging.

[Victor Moreau and his son practised the first joint résections]

Victor Moreau (1746-1799) and his son (1778-1846) were surgeons in Bar-le-Duc (French Department of Meuse). Victor Moreau invented the first joint resection technique in 1782 and submitted written comments to the "Académie Royale de Chirurgie" in 1782 then 1786 and 1789. At that time amputation was the only way of saving wounded and injured patients' lives and a conservative technique was an actual revolution in bone and joint surgery. His friend Pierre-François Percy was transmitted the technique in 1792. His son improved the technique and attempted to put it into widespread use through his thesis (1803) and the most famous essay of his in 1816. However the technique did not immediately succeed till Leopold Ollier's works proved the "bone regeneration by the periosteum" and the role of the "sub-capsular periosteum resection". Nowadays in spite of prosthesis progress some joint résections can be still indicated. At last Victor Moreau can be deemed the pioneer of the functional limb surgery.

Osteoarthritis and MR imaging

Although osteoarthritis (OA) is a common disease affecting millions of Americans, OA treatment is difficult to monitor because of the lack of consistent, objective disease standards. This article reviews the diagnosis and treatment of OA, with particular emphasis on the role of magnetic resonance (MR) in imaging the disease. After completing this article, readers will be able to: List the known risk factors for OA. Discuss normal and abnormal joint anatomy and physiology. Recognize OA symptoms. Describe diagnostic criteria for OA. Discuss the appearance of articular joint structures on MR. Explain the nonpharmacological and pharmacological treatment of OA. Discuss the role of MR in OA research.

Bilateral congenital diastasis of the inferior tibiofibular joint

Bilateral congenital inferior tibiofibular diastasis is an extremely rare anomaly of unknown etiology. A few cases have been reported previously. The author presents a case in which bilateral tibiofibulotalar arthrodesis was performed.

Synovial membrane expression of matrix metalloproteinases and tissue inhibitor 1 in juvenile idiopathic arthritides

OBJECTIVE

Matrix metalloproteinases (MMP) are a large family of proteolytic enzymes involved in the remodeling of extracellular matrix during tissue resorption. We investigated synovial tissue expression of the main proteolytic enzymes (MMP-1, MMP-3, and MMP-13) and tissue inhibitor of metalloprotease 1 (TIMP-1) in juvenile idiopathic arthritides (JIA).

METHODS

Expression of MMP-1, MMP-3, MMP-13, and TIMP-1 was studied by immunohistochemical analysis of synovial tissues, obtained at synoviectomy or arthroplasty from 9 patients with JIA, and was correlated with mononuclear cell infiltration into the lining layer.

RESULTS

MMP-1 and MMP-3 were abundantly expressed in the lining layer, showing a high degree of correlation with macrophage infiltration (CD68+ cells). MMP-13 showed a lower degree of expression, with tissue distribution almost restricted to the sublining regions. TIMP-1 tissue distribution was similar to that observed for MMP-1 and -3, although with a definitely lower number of positive cells.

CONCLUSION

The expression of MMP-1 and MMP-3 in the synovium of patients with IA was clearly correlated with the degree of inflammation. This indicates the possible role of MMP in the pathogenesis of synovitis in this group of pediatric idiopathic arthritides. Inadequate expression of tissue inhibitors may represent a crucial event for the development and perpetuation of tissue damage.

The natural limb is best: joint preservation and reconstruction by distraction osteogenesis for high-grade juxta-articular osteosarcomas

This paper introduces an innovative technique of highly conservative limb-saving surgery for juxta-articular osteosarcoma. This technique consists of marginal tumour excision, joint preservation and reconstruction by distraction osteogenesis. Ten patients, with a mean age of 19.5 years and high-grade osteosarcoma, underwent this procedure. The distal femur and proximal tibia were affected in five patients each. After effective pre-operative chemotherapy, the tumour was excised with preservation of the epiphysis, the articular surface and the maximun amount of healthy soft tissue. This was followed by application of an external fixator. Bone transport was performed for seven patients and shortening-distraction for three. The limb function was rated excellent in seven patients, good in one and fair in two. At the final follow-up, three patients were dead after a mean of 25.3 months while seven patients remained free of disease with a mean follow-up of 55.4 months. Joint preservation and biological reconstruction through distraction osteogenesis can produce excellent and long-lasting functional results.

[Multivariate analysis of factors influencing the effect of radiosynovectomy]

OBJECTIVE

In this prospective study, the time to remission after Radiosynovectomy (RSV) was analyzed and the influence of age, sex, underlying disease, type of joint, and duration of illness on the success rate of RSV was determined.

METHODS

A total number of 57 patients with rheumatoid arthritis (n = 33) and arthrosis (n = 21) with a total number of 130 treated joints (36 knee, 66 small and 28 medium-size joints) were monitored using visual analogue scales (VAS) from one week before RSV up to four to six months after RSV. The patients had to answer 3 times daily for pain intensity of the treated joint. The time until remission was determined according to the Kaplan-Meier survivorship function. The influence of the prognosis parameters on outcome of RSV was determined by multivariate discriminant analysis.

RESULTS

After six months, the probability of pain relief of more than 20% amounted to 78% and was significantly dependent on the age of the patient (p = 0.02) and the duration of illness (p = 0.05), however not on sex (p = 0.17), underlying disease (p = 0.23), and type of joint (p = 0.69).

CONCLUSION

Irrespective of sex, type of joint and underlying disease, a measurable pain relief can be achieved with RSV in 78% of the patients with synovitis, whereby effectiveness is decreasing with increasing age and progress of illness.

A population based assessment of the use of orthopedic surgery in patients with rheumatoid arthritis

OBJECTIVE

To describe the use of orthopedic surgery, including joint replacement surgery, in a well defined population based cohort of patients with rheumatoid arthritis (RA) and to identify characteristics that predict such use.

METHODS

A retrospective medical record review was performed of cases of RA incident in Rochester, MN, during the years 1955-85. Patients were followed until 1998. All joint surgeries were recorded, including joint reconstructive surgeries, total joint arthroplasty (TJA), and other joint reconstructive procedures (JRP) such as tendon transfers and resections, joint fusions, and surgeries for fractures and infections involving joints.

RESULTS

Of the total 424 RA incident cases, 148 (34.9%) patients underwent one or more (maximum of 20/patient) surgical procedures involving joints during their followup (median 14.8 yrs, range 0.2-42.8 yrs). Overall, this RA cohort had 9.7 surgeries per 100 person-yrs of followup. The estimated cumulative incidence of surgical procedures for RA at 30 yrs was 52.7% +/- SE 4.2. Surgeries for arthritis related joint disease of RA included: primary TJA 76 patients (31.3 +/- 4.1); JRP joint fusion 78 patients (29.4 +/- 3.5); JRP soft tissue 92 patients (29.8 +/- 3.3); and cervical spine fusion one patient. Non-RA (trauma and other) joint surgeries included TJA 26 patients (13.5 +/- 3.4) and arthrotomy for septic arthritis 8 patients (2.4 +/- 0.9). Based on Cox proportional hazards regression, the risk of having a disease related joint surgery for RA is increased in patients who are younger (p < 0.001), have positive rheumatoid factor (p = 0.01), and those with rheumatoid nodules (p < 0.001). There was a borderline significant increase in the risk of first joint surgery in women (p = 0.09). Women also had significantly more joint surgeries (11.5/100 person-yrs) than men (4.9/100 person-yrs; p < 0.001). Survival of patients who had surgery for RA related joint disease was similar to those who did not.

CONCLUSION

This is the first population based assessment of joint surgeries performed in patients with RA. Reconstructive surgeries were common, and women had significantly more surgeries than men. Survivorship among patients with RA undergoing surgeries was similar to that of the RA patient population at large.

A generic arthroscopy simulator architecture

Virtual Environments offer considerable potential to improve training for arthroscopic surgery. However, current systems are developed for individual joints, which requires healthcare providers to purchase and maintain multiple environments with differing interfaces and capabilities. This paper describes a generic arthroscopy system architecture that allows the fast development of training environments for any joint, each sharing a common user-interface. The use of the architecture in developing a simple ankle simulator is also described.

A 10 year prospective followup of patients with rheumatoid arthritis 1986-96

OBJECTIVE

To determine the 10 year outcome of hospital patients with established rheumatoid arthritis (RA) treated with disease modifying drugs (DMARD).

METHODS

All patients with RA of at least a year duration and attending a single clinician were followed prospectively for 10 years. DMARD treatments changed with time but were continued throughout. Measurements of joint tenderness (Ritchie Index), morning stiffness, grip, and disability (Health Assessment Questionnaire, HAQ) and radiographs of hands and feet were documented. A record of joint surgery was maintained. Patients who stopped attending the clinic were traced and an accurate record of deaths was obtained from the National Registry of Deaths. Paired clinical indices were compared where available between 0, 5, and 10 years.

RESULTS

At entry there were 289 patients of variable disease duration. Within 10 years, 71 had died (standardized mortality ratio 1.3) and 92 were alive but unavailable. Median joint tenderness, morning stiffness, grip strength, and hemoglobin were not significantly different at 0, 5, and 10 years. Erythrocyte sedimentation rate (ESR) declined but not significantly. By contrast, HAQ scores and radiographs worsened between 0 and 10 years (p = 0.0004, p = 0.0001, respectively). There was a trend toward lower ESR values and less disability and the lower radiographic scores in those with 10-15 years' disease duration in 1996 compared with those of similar duration in 1986. However, worsening of radiographs occurred in patients with short, medium, and long histories of RA. Correlations between disability, radiographic scores, and joint tenderness were apparent at the start and conclusion of the study. At 10 years, 54 (19%) of the original cohort had undergone at least one large joint replacement. Significantly more women required joint replacement surgery (chi-square 5.44, p = 0.02).

CONCLUSION

Over a 10 year period patients with RA exhibited an excess of deaths and a deterioration of radiographs and function despite regular DMARD treatment and apparent clinical containment. Worsening of radiographs occurred in both relatively early and late disease. There was a steady requirement for surgical large joint replacement with time. This study suggests that in the long term. the effect of DMARD treatments may be less than the expectations derived from short term studies.