Volume 17-3, Fall 2008

Bone morphogenetic proteins (BMPs) were first described by Dr. Marshall Urist in 1965. Since 1988 a series of clinical studies and randomized clinical trials have evaluated the application of these molecules in humans. A comprehensive review of 30 clinical studies was performed to elicit the existing evidence of the English orthopaedic literature. BMPs appear to be efficacious as the reported success rates are equivalent and perhaps superior to those achieved with the gold standard methods of autografting. Clinical safety assessments have been even more encouraging with just a few reports of adverse events related to their use in clinical practice. There are certain controversies on the presented results of all the reviewed clinical series, which reflect the complexity of the osteoinductive and osteoconductive role of the BMPs, the ongoing quest for optimization of the dosing schemes and delivery carriers, as well as the multifactorial interactions during bone formation and remodeling. (Journal of Surgical Orthopaedic Advances 17(3):133–146, 2008) Key words: applications, BMPs, bone morphogenetic proteins, clinical, review

Apoptosis in Osteoarthritis: Morphology, Mechanisms, and Potential Means for Therapeutic Intervention - Elizabeth O. Johnson, PhD, Antonia Charchandi, MD,1 George C. Babis, MD, and Panayotis N. Soucacos, MD, FACS

Semitendinosus and gracilis tendons taken from 25 cadaveric knees were investigated using light and electron microscopy, immunohistochemistry, and morphometry. Thickness of the collagen fibrils, fibril/interstitium ratio, density of blood vessels, density of fibroblasts, and distribution of the collagen fibrils (types I, III, and V collagen and elastic fibers) were analyzed. It was hypothesized that the difference in biomechanical stability between the gracilis and semitendinosus tendons could be reflected by different morphologic features. The results of this study showed that the gracilis tendon, in comparison with the semitendinosus tendon, provides a significantly higher fibril/interstitium ratio and a higher density of collagen III fibers. Conversely, the semitendinosus tendon provides a higher density of blood vessels and collagen I fibers. No differences regarding the density of fibroblasts, thickness of collagen fibrils, and elastic and type V collagen fibers were found. In conclusion, the gracilis tendon graft can provide approximately 15% more collagen than the semitendinosus tendon graft with the same thickness. This fact can play an important role for better biomechanical stability of the gracilis tendon. (Journal of Surgical Orthopaedic Advances 17(3):153–158, 2008) Key words: cadaveric study, comparative morphology, hamstring tendon, morphometry, semitendinosus/gracilis tendon

Proprioception is the sense of body position that is perceived both at the conscious and unconscious levels. Typically, it refers to two kinds of sensations: that of static limb position and of kinesthesia. Static position reflects the recognition of the orientation of the different body parts, whereas kinesthesia is the recognition of rates of movement. Proprioception is based on a multicomponent sensory system. There are various peripheral receptors that detect specific signals and major sensory afferent pathways that carry the information from the spinal cord up to the cortex. There are parallel pathways, some of which serve conscious proprioception, and others that serve subconscious proprioception. Conscious proprioception is relayed mostly by the dorsal column and in part by the spinocervical tract. Finally, the organ of perception for position sense is the sensory cortex of the brain. This review outlines the current understanding of these complex neural pathways, starting from the peripheral receptors and working up toward the center of perception, the brain. (Journal of Surgical Orthopaedic Advances 17(3):159–164, 2008) Key words: axon, dorsal tracts, kinesthesia, mechanoreceptors, peripheral nerve, position sense, spinocervical tract

Revision knee arthroplasty should be regarded as a discipline separate from primary surgery. A disciplined approach to diagnosis is mandatory in which the following categories for failure are useful: (a) sepsis, (b) extensor mechanism rupture, (c) stiffness, (d) instability, (e) periprosthetic fracture, (f) aseptic loosening and osteolysis, (g) patellar complications and malrotation, (h) component breakage, and (i) no diagnosis. In the event of no coherent explanation for pain and disability, the possibilities of chronic regional pain syndrome, hip or spine pathology, and inability of current technology to meet patient expectations should be considered and revision surgery should be avoided. Revision arthroplasty cannot be performed as if it were a primary procedure and indeed will be eight (or more) different surgeries depending on the cause of failure. Though perhaps counterintuitive, there is a logical rationale and empirical evidence to support complete revision in virtually every case. In general, revision implant systems are required. The early dependence on the ‘‘joint line’’ is inadequate, failing as it does to recognize that the level of the articulation is a three-dimensional concept and not simply a ‘‘line.’’ The key to revision surgery technique is that the flexion gap is determined by femoral component size and the extension gap by proximal distal component position. Accordingly, a general technical pathway of three steps can be recommended: 1) tibial platform; 2) stabilization of the knee in flexion with (a) femoral component rotation and (b) size selected with evaluation of (c) patellar height as an indication of ‘‘joint line’’ in flexion only; and 3) stabilization of the knee in extension, an automatic step. Stem extensions improve fixation and, if they engage the diaphysis, may be used as a guide for positioning. Porous metals designed as augments for bone defects may prove more important as ‘‘modular fixation interfaces.’’ It is postulated that with the exception of septic and extensor mechanism complications, first revision knee arthroplasty may exceed the durability of primary knee arthroplasty. (Journal of Surgical Orthopaedic Advances 17(3):165–172, 2008) Key words: complications, extensor mechanism rupture, fixation, fracture, instability, knee arthroplasty, patella, revision, sepsis, stiffness, technique

The incidence of periprosthetic knee infection is generally low, but the economic impact is great. Treatment should take into account the acuteness of the infection, the overall immune/medical status of the patient, and the local factors at the site of the infection. The aim of this study was to evaluate the two-phase exchange arthroplasty with the use of antibiotic impregnated articulating spacer, as an alternative treatment of chronic periprosthetic knee infection in patients with minimum systemic and no local compromising factors. Staphylococcus aureus was the most common pathogen followed by Staphylococcus epidermidis and Pseudomonas aeruginosa. Twenty-four patients were treated with this regiment. All of them returned to normal everyday activity and no infection recurrence was noted over a 2- to 10-year follow-up. Excellent long-term results can be achieved for patients staged as III-A-1 and III-B-1 according to the Musculoskeletal Infection Society staging system, when treated with the aforementioned protocol and intravenous antibiotics. (Journal of Surgical Orthopaedic Advances 17(3):173–178, 2008) Key words: antibiotic-impregnated articulating spacer, compromising factors, periprosthetic knee infection, two-phase exchange arthroplasty

One hundred thirty-six knees were treated with the Endomodel rotating hinge knee prosthesis as primary total knee arthroplasty (TKA). The indications for surgery included osteoarthritis (110 knees), rheumatoid arthritis (18 knees), and osteonecrosis (8 knees). Patients were divided into four study groups according to follow-up duration. Group A was followed up from 10 to 15 years, group B from 8 to 10 years, group C from 5 to 8 years, and group D from 2 to 5 years. The Hospital for Special Surgery knee score, as well as each parameter individually, showed statistically significant improvement in all groups postoperatively. A total of 88.23% were rated as excellent, 3.67% as good, and 8.08% as fair. The results suggest that the Endomodel rotating hinge prosthesis can be considered a good alternative for primary TKA in cases of serious axial deformity and collateral ligament deficiency and in rheumatoid arthritis patients. (Journal of Surgical Orthopaedic Advances 17(3):179–184, 2008) Key words: Endomodel, knee osteoarthritis, rotating hinge prosthesis

Periacetabular osteotomy has become the procedure of choice in many centers for the treatment of symptomatic hip dysplasia in young patients without severe secondary hip arthritis. Reorientation pelvic osteotomy has the potential for large blood loss and the need for blood transfusion. Between 1996 and 2003, 108 periacetabular osteotomies (107 patients) were performed by one of the authors. There were 84 females and 23 males with an average age of 30 years at the time of surgery. The overall allograft transfusion rate was 20% (21/108). Ninety-four percent (101/108) of the patients received transfusions including autologous blood, intraoperative cell saver, and postoperative allograft transfusion. The average transfusion amount (cell saver and allograft) was 2.14 units per patient. The risk for transfusion between males and females was not significantly different. The data from this study suggest that the vast majority of patients undergoing periacetabular osteotomy will require some form of transfusion, with 20% requiring allograft blood. The need for allograft blood will be minimal if the preoperative hemoglobin is greater than 12 g/dL. (Journal of Surgical Orthopaedic Advances 17(3):185–187, 2008) Key words: blood loss, periacetabular osteotomy

The purpose of this study was to assess the long-term results of an extended soft tissue release in a single procedure, for the treatment of congenital idiopathic clubfoot. Seventeen patients with 22 congenital idiopathic clubfeet were treated surgically with the 12-in-1 procedure. The majority of cases were grade III (severe) deformities. The procedure consisted of dividing or lengthening 12 elements of the posterior, medial, and plantar side of the foot. The mean follow-up period was 11 years (range, 7-18 years). Revision surgery was required within 1 to 3.5 years of the initial procedure in four cases (residual deformity), whereas in another patient, bilateral camptodactyly was corrected 11 years postoperatively. At the time of the most recent follow-up, and after the revision procedures in patients with residual or recurrent deformities, results were excellent in 8 and good in 14 cases. The long-term follow-up results of the 12-in-1 procedure are encouraging for the treatment of idiopathic congenital clubfoot. (Journal of Surgical Orthopaedic Advances 17(3):188–192, 2008) Key words: congenital idiopathic clubfoot, long-term follow-up, soft tissue release, surgical treatment

Late postoperative infection following instrumented spinal surgery is a clinical entity that has emerged in recent years. The extended surface of the spinal instrumentation in combination with hematogenous seeding or intraoperative inoculation is the main predisposing factor. In order to investigate the contribution of the instrumentation material (stainless steel versus titanium implants) and mechanical loosening, two groups of patients are presented. The first group includes 50 idiopathic scoliotic patients who were treated with first-generation posterior stainless steel spinal segmental multihook instrumentation [Texas Scottish Rite Hospital (TSRH) instrumentation system], and the second group includes 45 similar patients who were treated with newer titanium implants (MOSS MIAMI, XIA, and CD). Follow-up ranged from 3 to 13 years. Six patients from the first group and one patient from the second group presented with late infections 1 to 7 years postoperatively. Common intraoperative findings were excessive inflammatory tissue and some degree of instrumentation loosening and corrosion (stainless steel). Removal of instrumentation in combination with appropriate antibiotics was an effective treatment. Further study with long-term follow-up is necessary in order to understand the exact incidence and pathology of such infections. (Journal of Surgical Orthopaedic Advances 17(3):193–199, 2008) Key words: instrumentation loosening, late postoperative spinal infections, metal corrosion, stainless steel implants, titanium implants

As the field of orthopaedic surgery continues to expand in terms of indications and technologies, there has been increasing emphasis placed on validated patient-derived outcome measures in clinical orthopaedic research. As concerns mount regarding rising health care costs, declining quality, and variability in clinical practice patterns, outcome measures become important tools in assessing quality. Furthermore, outcome measures can be utilized to justify the clinical benefits of existing and new diagnostic modalities and surgical interventions. This review provides a brief overview of traditional outcomes approaches in orthopaedics followed by a discussion of the current trend toward patient-centered outcomes research and its role in the emerging field of cost-effectiveness analysis in orthopaedics. (Journal of Surgical Orthopaedic Advances 17(3):200–203, 2008) Key words: cost-effectiveness analysis, health care technology, outcomes measurement

Wide resection and limb-salvage surgery remain the gold standard for the management of patients with soft tissue sarcomas of the extremities. Innovations in understanding tumor biology and limbsalvage techniques have led amputation rates to decline. Radiation therapy and novel chemotherapy agents and dosing regimens are supplementing oncology-related surgical treatment. A multidisciplinary team approach with input from oncologists, pathologists, radiation oncologists, and orthopaedic and plastic surgeons is necessary for the management of patients with soft tissue sarcomas of the extremities. (Journal of Surgical Orthopaedic Advances 17(3):204–215, 2008) Key words: amputation, chemotherapy, limb-salvage surgery, microsurgical reconstruction, radiation, soft tissue sarcomas

The opportunity to become President of the Clinical Orthopaedic Society (COS) makes me appreciate the opportunities that orthopaedic surgery has given me through the years. This honor as President of COS is especially gratifying. Whether early,mid, or late career,we as orthopedists inherit the good things which have come from the past generations. Not only do we respect the “greatest generation” (1) with their toughness and their feel for family but, yes, the development of the world of orthopaedic surgery. Outgoing president Ken Moore’s footprints and those preceding him as president are large and represent effective, devoted, and responsible leadership. These men (no women yet) are a valuable part of COS history.