Robert R. Karpman

In vivo chondroprotection and metabolic synergy of glucosamine and chondroitin sulfate.

Supplements of glucosamine hydrochloride, low molecular weight chondroitin sulfate, and manganese ascorbate were tested separately and in combination for their ability to retard progression of cartilage degeneration in a rabbit instability model of osteoarthrosis. Computerized quantitative histologic evaluation of safranin O stained sections of the medial femoral condyles measured the grade and extent of tissue involvement of lesions. Severe lesions (Mankin grade greater than 7) were absent in all animals supplemented with a dietary mixture of glucosamine, chondroitin sulfate, and manganese ascorbate. Total linear involvement (mm of lesioned surface) and total grade (mean grade × number of lesions per animal) were reduced significantly in animals given the combination compared with controls (59% and 74% respectively). Animals supplemented with glucosamine, chondroitin sulfate, or manganese ascorbate alone had less moderate and severe tissue involvement than controls but not to the extent of the combined group. In vitro, a combination of glucosamine hydrochloride and chondroitin sulfate acted synergistically in stimulating glycosaminoglycan synthesis (96.6%). Chon-droitin sulfate and manganese ascorbate but not glucosamine were effective in inhibiting degradative enzyme activity. These data suggest that the disease modifying effect (the ability to retard progression of cartilage degeneration) of a mixture of glucosamine, chondroitin sulfate, and manganese ascorbate is more efficacious than either agent alone.

Differential Effects of Nicotine and Smoke Condensate on Bone Cell Metabolic Activity

Objective: Delayed or impaired healing of skeletal trauma in patients who smoke has been attributed to vascular responses of nicotine absorption and/or a direct effect of nicotine or other smoke components on bone cells. In vivo studies indicate variability in osteosynthetic response to nicotine versus smoke inhalation. We tested the hypothesis that components of cigarette smoke other than nicotine may be responsible for the adverse skeletal effects of smoking. Design: In vitro cultures of MC3T3-E1 osteoblastlike cells were exposed to varying doses of nicotine or condensates of cigarette smoke. Metabolic assays included alkaline phosphatase activity, collagen synthesis, and total protein synthesis as well as cell proliferation. Results: Variations in the degree of response were noted between bone cell preparations. Nicotine elicited a significant dose-dependent stimulation of bone cell metabolism in all studies. This was detected as increases in alkaline phosphatase activity and increases in total protein and collagen synthesis. Responses were noted with nicotine doses as low as 12.5 ng/mL (half the nicotine level circulating in smokers). In one study, maximum stimulation occurred at 250 ng/mL with levels reaching 74% (total protein) and 104% (collagen) greater than control cultures. In a second study, 222% and 627% stimulation of protein and collagen synthesis over controls was noted using 100 ng/mL. Addition of the nicotine receptor antagonist mecamylamine reduced the nicotine stimulation. Preparations of smoke condensate with equivalent nicotine concentrations reduced all indices of metabolic activity. Cell proliferation was stimulated by both nicotine (20-25%) and smoke condensate (38-46%). Conclusion: The data suggest that nicotine acts as a direct stimulant of bone cell metabolic activity. Smoke condensate containing equivalent levels of nicotine elicits an inhibitory effect. A probable speculation is that the delay in clinical healing of skeletal trauma in smoking patients may in part be a result of absorption of components of smoke other than nicotine.

Evaluation of autologous shed blood for autotransfusion after orthopaedic surgery

Autologous shed blood for autotransfusion was evaluated at four medical centers in a prospective randomized study. One hundred twenty-eight patients were studied after hip replacement, knee replacement, or spine fusion. The efficacy of autologous shed blood in reducing homologous transfusion was evaluated. The relative risk of transfusion with homologous blood was 0.4 in patients who received shed blood compared with patients who did not receive shed blood. The reinfusion of shed blood reduced the requirement for homologous blood by 60%. Two filter systems were evaluated in reinfusing autologous shed blood. The Pall RC100 filter appeared to be more effective than the Pall 40-mu screen filter in removing fat particles and white blood cells. No significant clinical abnormalities were discovered after autotransfusion with autologous shed blood. Evaluation of clotting studies showed no significant differences between patients who received shed blood and patients who received liquid-preserved red blood cells. These data indicate that unwashed autologous shed blood from orthopaedic wound drainage is a safe and effective substitute for transfusion of autologous predonated blood or homologous liquid-preserved red blood cells.

Complications of the PCA anatomic patella.

A retrospective review of the total knee arthroplasties performed using the PCA anatomic patella (Howmedica, Rutherford, NJ) was undertaken after a high rate of complications was noted. Eighty-seven knees in 75 patients were evaluated with an average follow up of 16 months. Eighteen complications of the patella in 14 knees were found (16%); these included lateral subluxation (10 knees), fracture of the patella (5 knees), patellar tendon rupture (2 knees) and prosthetic loosening (1 knee). Seven patients required secondary procedures with the ultimate result greatly compromised in four patients. It is proposed that if the component is not precisely aligned, the eccentric shape and central ridge increases the forces acting at the patella and leads to an increased risk for complications, making the component less forgiving than the more standard dome-shaped patellar component.

Early failure of noncemented porous coated anatomic total hip arthroplasty.

From July 1984 through October 1987, 63 consecutive primary Porous Coated Anatomic total hip arthroplasties were performed. Follow-up observation ranged from one to four years, with a mean of 2.4 years. The mean postoperative Harris hip score in 81 cases was 38% excellent results, 23% good results, 6% fair results, and 23% poor results. Eight percent of hips required revision of the femoral component related to subsidence. Persistent thigh pain was found in 33% and persistent limp in 58%. Poor clinical outcome was correlated with persistent thigh pain and 3 mm or more subsidence of the femoral component. Subsidence occurred despite adequate canal fill. This high percentage of early failure is unacceptable when compared with standard techniques of total hip replacements with cement fixation.

OSTEOTOMY VERSUS UNICOMPARTMENTAL PROSTHETIC REPLACEMENT IN THE TREATMENT OF UNICOMPARTMENTAL ARTHRITIS OF THE KNEE

Forty patients (44 knees) with unicompartmental arthritis of the knee were reviewed to assess the overall functional result following high tibial osteotomy as compared to unicompartmental prosthetic replacement. All patients were evaluated both pre- and postoperatively using a standardized computer form. Mean followup was 24 months in the osteotomy group, and 41 months in the prosthetic replacement group.Results in the osteotomy group were rated excellent in two patients, good in nine, and poor in 12. Results in the prosthetic replacement group were rated excellent in 10, good in nine and poor in two. We therefore believe that unicompartmental replacement offers a viable alternative to high tibial osteotomy in the treatment of unicompartmental arthritis of the knee if proper patient selection and precise component placement is employed.

Professionalism and professional values in orthopaedics.

During a consensus conference in Fall, 1998, the Academic Orthopaedic Society identified the values and qualities of professionalism as defined by its members. One hundred eighty-six respondents rated 20 characteristics and values describing professionalism, based on the extent to which they believed each item was appropriate. The five items receiving highest average ratings were: integrity, trustworthiness, responsibility, reliability, and accountability. Principal components analysis yielded five factors that captured 62% of the total variability. These factors were labeled respect and relationships, altruism, accountability and reliability, integrity, and excellence. The authors anticipate that the Academic Orthopaedic Society will find these data useful, and incorporate this information into their decisions concerning evaluation of current residents and applicants to their programs. An additional challenge will be to develop a values curriculum (formal curriculum) and a learning environment (informal curriculum) that will encourage residents and faculty to aspire to the highest in professional values and professional conduct.

Musculoskeletal disease in the United States: who provides the care?

Musculoskeletal care is a big business in the United States. It is estimated that the cost of musculoskeletal care is in excess of

The lithotriptor and its potential use in the revision of total hip arthroplasty.

215 billion per year. Although orthopaedic surgeons are responsible for providing musculoskeletal care, a significant proportion of care is rendered by other healthcare providers including primary care physicians, neurosurgeons, physiatrists, podiatrists, physical therapists, and a cadre of alternative care providers including chiropractors, acupuncture specialists, and naturopaths. The purpose of the current study is to provide data regarding the provision of musculoskeletal care by those other than orthopaedic surgeons to determine what, if any, concerns exist among other providers regarding manpower issues, and to suggest alternatives for orthopaedic surgeons to maintain or perhaps increase their proportion of musculoskeletal care in the United States.

Arthrography of the Metatarsophalangeal Joint

Revision total hip arthroplasty, particularly femoral component replacement, has proved extremely difficult and has met with frequent complications. Despite a variety of devices and techniques that have been developed to facilitate removal of the femoral stem, the procedure remains difficult. Extracorporeal shock wave lithotripsy (ESWL) is a new technique initially created to pulverize renal stones by means of repetitive shock waves delivered to a discrete area. It was felt that perhaps this technique might also be utilized to facilitate the removal of the femoral component and cement from the femoral canal in revision total hip arthroplasty. Using bone cement, cadaveric canine femora were implanted with stainless steel rods placed within the medullary canal. The implanted femora were treated with ESWL, sectioned, and examined, using scanning electron microscopy. Microfracturing of the cement and a disruption of the cement bone interface were seen in the treated specimens. ESWL has the potential to be used prior to revision total hip arthroplasty to facilitate cement and component removal, although there are several questions that need to be answered prior to considering its clinical use. The incidence of revision of failed cemented total hip replacement is rapidly increasing and, consequently, there have been numerous developments of new techniques to improve the efficacy of this complex surgical procedure. It has been recently estimated that more than 100,000 total hip arthroplasties are done every year, and revision rates for clinical failure have been variously reported between 1% and 29%. The incidence of failure will continue to increase, since roentgenographic evidence of aseptic loosening appears to increase as a function of time. This is complicated by the poor long-term results of the revision procedures, eg, second revisions (9%), increased incidence of radiographic loosening (53%) and symptomatic loosening (14%) of the femoral component, and a continuing attrition in the rate of mechanical failure of 29%. Hoogland and co-workers reported that a second revision was required in 22% of their revision total hip replacement series. More recently, Tapadiya and associates reported a second-revision rate of 29% after revision for total hip replacement component loosening based on an average follow-up period of 3.1 years. Recent advances in materials, techniques, and instrumentation have not demonstrated an improvement in more recently treated patients who have had revision arthroplasties. One of the more challenging technical aspects of revision procedures is the removal of adherent cement from the femoral canal within the diaphyseal region. This has been addressed with an armamentarium of techniques, beginning with the “window,” or “gutter,” cut into the cortical bone. This technique was eliminated with the advent of intramedullary hand and powered drilling instrumentation, fiberoptic headlights, and sliding hammer extractors. Unfortunately, numerous intraoperative complications have occurred, such as perforation of the femoral cortex by the drilling, instruments due to difficulties in differentiating between the hard, brittle cement and adjacent cortical bone, particularly in the intramedullary canal at the level of the isthmus, where blind drilling becomes hazardous. Hoogland and associates reported a 12% rate of intraoperative complications, including femoral shaft fracture during cement removal, femoral shaft perforation, and severe hypotensive crisis secondary to heavy blood loss. Inadvertent perforation of the femoral shaft occurred in 14% of the revision cases Number 387 June, 2001 The Classic 5 Fig 1. Dr. Robert R. Karpman. (Reprinted with permission from Karpman RR, Magee FP, Gruen TWS, Mobley T: The lithotriptor and its potential use in the revision of total hip arthroplasty. Orthop Rev 16:38–42, 1987.) during the attempt to remove cement from the intramedullary canal. There continues to be a persistent need for research and innovation to identify a more efficient method of facilitating cement removal. One high technology approach involved an attempt to use lasers, but no further information on this application has been reported. Extracorporeal shock wave lithotripsy (ESWL) is a new technique presently being used to pulverize renal stones by means of repetitive shock waves delivered to a discrete area. This technique may be effective in disrupting the bone/cement interface prior to revision surgery to facilitate cement removal. A Shattering Technique ESWL, a noninvasive, contact-free, kidneystone shattering technique, was developed in Munich in the mid 1970s and has now been brought into common use in West Germany, the United States, and Sweden. In principle, the shock waves are generated by an underwater high-voltage condenser spark discharge and then focused at the renal stone, using an elliptical reflector. The position of the stone is located by a two-axis x-ray system, whose axes intersect at the second focus of the elliptical reflector. The patient is moved with a high-precision positioning device in three axes so that the stone can be in the second focus with a precision of 1 cm. The shock waves spread through the immersed body evenly, since the acoustic impedance of most body tissue is close to that of water. At the second focus, where the stone with a substantially different density is encountered the shock waves are highly attenuated, leading to a buildup of pressure gradients and formation of tear-and-shear forces. These forces are sufficient to disintegrate the solid kidney stone into small residual concretions, permitting spontaneous discharge. The entire procedure lasts 30 to 45 minutes. This technique has been extremely effective in the treatment of renal and ureteral stones, often relieving the need for open procedures. It was felt by our group that perhaps this technique might also be utilized to facilitate the removal of the femoral component and cement from the femoral canal in revision total hip arthroplasty. The purpose of this paper is to present preliminary observations of the utilization of ESWL in canine cadaver bone to evaluate its disruptive effects on the bone/cement interface. Materials and Methods Three freshly harvested adult canine femora were implanted with a 7-mm 50-mm stainless steel cylindrical rod using cement fixation (Fig 1). The implantation was carried out by inserting a 3.2-mm Steinmann pin at the trochanteric fossa and entering the proximal medullary canal. A 9-mm cannulated reamer was placed over the pin and the medullary canal reamed to a depth of 60 mm. All reaming -debris and marrow were removed from the femoral canal using suction and irrigation. After placing a medullary plug at the 60-mm level, the canal was filled with polymethyl methacrylate (Surgical Simplex P, Howmedica, Inc) using a cement gun. The stainless steel rod was pressed into the canal, centered, and then fully seated. After 24 hours, the implanted femora were placed in the Dornier Kidney Lithotriptor (Dornier Medical Systems, Munich, West Germany). The lithotriptor includes a water bath in which the test specimen is submerged. A shock wave generator, consisting of a spark plug and a focusing ellipse, is used to generate shock waves and direct them toward the target point. Utilizing a two-axis C-arm image-intensification system, a target location was selected along the length of the femur in the area of the cement/bone interface, and 100 shock waves were delivered (Fig 1) (figure not shown). Using this imaging system, the target spot can be placed in the required position with a precision of 1 cm. High-resolution radiographs of the implanted femur were taken prior to and following lithotriptor treatment on Kodak X-Omat AR film (Eastman Kodak Co, Rochester, NY) in a Megarad 160 (Omega Laboratories, Inc, Los Angeles, Calif.). The specimen was reClinical Orthopaedics 6 Karpman and Related Research