Biomedical subjects

R A Berger

Publications and source records attributed to R A Berger.

At least 37 records · Page 2Linked to original sources

PubMed2001

Second-generation cementless total hip arthroplasty. Eight to eleven-year results.

BACKGROUND: Second-generation cementless femoral components were designed to provide more reliable ingrowth and to limit distal osteolysis by incorporating circumferential proximal ingrowth surfaces. We examined the eight to eleven-year results of total hip arthroplasty with a cementless, anatomically designed femoral component and a cementless hemispheric acetabular component. METHODS: Ninety-two consecutive primary total hip arthroplasties with implantation of a femoral component with a circumferential proximal porous coating (Anatomic Hip) and a cementless hemispheric porous-coated acetabular component (Harris-Galante II) were performed in eighty-five patients. These patients were prospectively followed clinically and radiographically. Six patients (seven hips) died and five patients (seven hips) were lost to follow-up, leaving seventy-four patients (seventy-eight hips) who had been followed for a mean of ten years (range, eight to eleven years). The mean age at the time of the arthroplasty was fifty-two years. RESULTS: The mean preoperative Harris hip score of 51 points improved to 94 points at the time of final follow-up; 86% of the hips had a good or excellent result. Thigh pain was reported as mild to severe after seven hip arthroplasties. No femoral component was revised for any reason, and none were loose radiographically at the time of the last follow-up. Two hips underwent acetabular revision (one because of dislocation and one because of loosening). Kaplan-Meier survivorship analysis was performed with revision or loosening of any component as the end point. The ten-year survival rate was 96.4% +/- 2.1% for the total hip prosthesis, 100% for the femoral component, and 96.4% +/- 2.1% for the acetabular component. Radiolucencies adjacent to the nonporous portion of the femoral component were seen in sixty-eight (93%) of the -seventy-three hips with complete radiographic follow-up. Femoral osteolysis proximal to the lesser trochanter was noted in four hips (5%). No osteolysis was identified distal to the lesser trochanter. Periacetabular osteolysis was identified in twelve hips (16%). Five patients underwent exchange of the acetabular liner because of polyethylene wear. CONCLUSIONS: This second-generation cementless, anatomically designed femoral component provided excellent clinical and radiographic results with a 100% survival rate at ten years. The circumferential porous coating of this implant improved ingrowth and prevented distal osteolysis at a mean of ten years after the arthroplasty.

Acetabulum↗

PubMed2001

Functional ligamentous anatomy of the trapezium and trapeziometacarpal joint (gross and arthroscopic).

A detailed description of the ligamentous anatomy of the thumb basal joint is presented from a gross, arthroscopic, and functional point of view. All 16 ligaments that stabilize the trapezium and trapeziometacarpal (TM) joint are discussed in association with their presumed functional relevance regarding trapezial and trapeziometacarpal joint stability. Geometric and mathematical models are introduced to help describe and support anatomic observations with regard to ligament function. The dorsoradial ligament appears to be an important stabilizer of the TM joint against dorsally directed forces. The trapeziotrapezoid, trapezio-II metacarpal, and trapezio-III metacarpal ligaments appear to function as tension bands to help support the trapezium against cantilever bending forces imparted onto the trapezium by the thumb metacarpal.

Arthritis↗

PubMed2001

The anatomy of the scaphoid.

The scaphoid is a critical link in the mechanism of the carpus. Its complex shape allows it to participate in the kinematics of both the proximal and distal row. Because of its offset proximal and distal articular surfaces, it has a natural tendency to palmar-flex with longitudinal loading. Because of this, extension of the scaphoid places progressively increasing tension on the palmar cortex of the curved waist of the scaphoid. Excessive extension or ulnar deviation of the wrist, coupled with excessive loading, mechanically predisposes the scaphoid to fracture. This is especially true if the strong ligaments attaching to the scaphoid retain their integrity. When a fracture occurs proximal to the waist of the scaphoid, it is predisposed to displacement because of the opposing forces on the proximal [table: see text] and distal fragments as well as the distribution of ligament attachments. This, in turn, predisposes the proximal fragment to ischemic conditions because of the distal location of nutrient vessels and a retrograde intraosseous blood supply.

Biomechanical Phenomena↗

PubMed2000

The dorsopalmar stability of the distal radioulnar joint.

Sixteen fresh-frozen adult human cadaveric upper extremities were used in a biomechanical analysis of distal radioulnar joint (DRUJ) stability. The relative contribution to stability of the DRUJ by the surrounding anatomic structures presumed to stabilize the joint was analyzed with respect to forearm rotation and wrist flexion and extension using a purpose-built 4-axis materials testing machine. The dominant structures stabilizing the DRUJ were the ligamentous components of the triangular fibrocartilage complex proper. The major constraint to dorsal translation of the distal ulna relative to the radius is the palmar radioulnar ligament. Palmar translation of the distal ulna relative to the radius is constrained primarily by the dorsal radioulnar ligament, with secondary constraint provided by the palmar radioulnar ligament and interosseous membrane. The ulnocarpal ligaments and extensor carpi ulnaris subsheath did not contribute significantly to DRUJ stability; however, approximately 20% of DRUJ constraint is provided by the articular contact of the radius and ulna. These relationships were consistent regardless of wrist position or degree of forearm rotation.

Adult↗

PubMed2000

Serum titanium level for diagnosis of a failed, metal-backed patellar component.

A case is presented in which an elevated serum titanium level was used to make the diagnosis of a failed metal-backed patellar component. The preoperative serum titanium level was 536.8 ppb, which was 98 times higher than the patient's previous level (taken 1 year earlier, when he was asymptomatic) and 2 orders of magnitude higher than the expected level with a well-functioning implant of this type. Revision surgery confirmed that the polyethylene portion of the patellar component had worn through, leaving the titanium portion of the patellar implant to articulate with the femoral component. Wear-through was not evident on preoperative radiographs or clinical examination. As knowledge about the expected ranges for serum metal ion levels after total joint arthroplasty continues to increase, the diagnostic utility of serum metal ion testing in the evaluation of joint arthroplasty function will continue to improve.

Aged↗

PubMed2000

T incision for exposure of the distal radius and wrist.

A retrospective review of 66 T-shaped incisions for exposure of the dorsal distal radius and wrist was performed. The incision provided excellent exposure in all cases and no additional incisions were required. Cosmesis was considered acceptable by all patients. Complications occurred in 6% and were more likely in patients undergoing fixation of acute distal radius fractures using Kirschner wires which protruded through the skin flaps.

Adolescent↗

PubMed2000

[Complete superficial replacement of the middle finger joint--long-term outcome and surgical technique].

Pain, weakness, malalignment and limited range of motion (ROM) at the PIP joint following arthrosis (degenerative or post-traumatic) or rheumatoid arthritis frequently require surgical treatment. PIP joint fusion or implantation of a prosthetic device are options. The purpose of this study was to report our long-term results with a surface replacement PIP arthroplasty (SR PIP arthroplasty) and the description of our operative technique. 82 prostheses were done in 60 patients between 1980 and 1999. All patients were reexamined, the average follow up was 64 months (12 to 260 months); average age was 57 years. 48 patients were operated on the right hand, 12 on the left hand. 44 patients were female, 16 were male. All patients complained of pain preoperatively. Patients were divided into three groups: A degenerative arthrosis, B posttraumatic arthrosis and C inflammatory arthritis. Active range of motion of all fingers of the operated hand, grip-strength, pain relief, joint stability or deformity and comprehensive radiographic assessment were studied. The subjective impressions of the patients were measured in four grades: very satisfied--satisfied--dissatisfied--very dissatisfied. Finally the investigators divided the overall results in: good--fair--poor. The average flexion arc was 31 degrees (maximum 15 degrees hyperextension to 95 degrees flexion) preoperatively and 47 degrees (maximum 14 degrees hyperextension to 90 degrees flexion) postoperatively. Over 70% of the patients had complete pain relief. In 12 fingers secondary procedures were necessary, usually related to soft tissue deformity and extensor tendon function. No arthrodesis was performed as a following operation. In 40 fingers a good result was achieved (49%), 25 had a fair (30%) and 17 (21%) a poor result. Our results of resurfacing PIP arthroplasty are encouraging and provide equal and usually improved motion in comparison with other joints. With experience and refinements of the operative technique our confidence in surface replacement arthroplasty has increased. For this reason we prefer this procedure for posttraumatic or degenerative arthrosis as against PIP joint fusion or silastic implants.

Aged↗

PubMed2000

Hybrid total hip arthroplasty with a precoated offset stem. Four to nine-year results.

BACKGROUND: Use of modern cementing techniques for fixation of femoral components in total hip arthroplasty has had excellent clinical and radiographic results in most patients. However, several authors have described early loosening of femoral components with roughened and precoated finishes. The purpose of this study was to examine the performance of the precoated Iowa stem, which has increased offset, and to compare the results with those of another cemented precoated femoral component with standard offset used at our institution. METHODS: We carried out a prospective analysis of 102 primary hybrid total hip arthroplasties (a cementless acetabular component and a cemented femoral component) performed with use of the Iowa femoral component in ninety-five patients at our institution. The Iowa stem was used in hips that required greater offset than is available with standard stems as determined by preoperative templating. The average age of the patients at the time of the index procedure was sixty-nine years. Sixteen patients (seventeen hips) died before the forty-eight-month minimum follow-up period had elapsed. Two patients were lost to follow-up, and radiographic follow-up was incomplete for one. The mean duration of clinical and radiographic follow-up of the remaining eighty-two hips in the seventy-six surviving patients was sixty-five months (range, forty-eight to 104 months). RESULTS: The average preoperative Harris hip score of 47 points (range, 16 to 69 points) improved to an average of 87 points (range, 24 to 100 points) at the time of the review. Two hips underwent femoral component revision. Four femoral stems were radiographically loose at an average of thirty-four months. Femoral osteolysis was seen in five hips (6 percent) at an average of fifty-four months postoperatively. No acetabular component was revised because of aseptic loosening. According to Kaplan-Meier analysis, the seven-year survival rate, with an end point of femoral revision, osteolysis, or stem debonding, was 90.6 percent (95 percent confidence interval, 0.87 to 0.94). CONCLUSIONS: The prevalence of revision, osteolysis, and loosening after total hip arthroplasty with the Iowa femoral component at our institution was higher than that seen in our series of Harris Precoat stems, which had a survival rate of 98.4 percent (95 percent confidence interval, 0.97 to 1.00) at ten years with the same end points. The design of the Iowa stem may make it difficult to achieve a good cement mantle, and, in combination with the geometry and increased offset of the stem, may compromise the long-term survival of this cemented femoral component.

Acetabulum↗

PubMed1999

An anatomic study of the stabilizing ligaments of the trapezium and trapeziometacarpal joint.

We provide a detailed and comprehensive anatomic description of the ligaments stabilizing the trapezium and trapeziometacarpal joint. Sixteen ligaments were identified. Fourteen ligaments inserted onto the trapezium and 2 others attached independently to the thumb metacarpal. The ligaments inserting onto the trapezium were the superficial anterior oblique, deep anterior oblique (beak ligament), dorsoradial, posterior oblique, ulnar collateral, dorsal trapezio-trapezoid, volar trapezio-trapezoid, dorsal trapezio-second metacarpal, volar trapezio-second metacarpal, trapezio-third metacarpal, volar scaphotrapezial, radial scaphotrapezial, transverse carpal, and trapezio-capitate ligaments. The remaining 2 ligaments attach onto the thumb metacarpal and are the proper intermetacarpal and the dorsal intermetacarpal. The dorsoradial and deep anterior oblique ligaments play a substantial role in stabilizing the trapeziometacarpal joint, and the deep anterior oblique ligament may function as a pivot for the first metacarpal during palmar abduction to allow rotation (pronation). The dorsal trapezio-second metacarpal, volar trapezio-second metacarpal, and trapezio-third metacarpal ligaments function as tension bands and are required to prevent instability from cantilever bending forces on the trapezium.

Aged↗

PubMed1999

Constraint and material properties of the subregions of the scapholunate interosseous ligament.

The material and constraint properties of the dorsal, proximal, and palmar regions of the scapholunate ligament were studied using isolated bone-ligament-bone preparations from 24 adult intact cadaver wrists. Determinations of constraint to differential rotation and translation as well as failure strength were made using a servohydraulic testing machine incorporating an additional rotatory actuator. The dorsal region of the scapholunate ligament offered the greatest constraint to differential translation, while both the dorsal and palmar regions demonstrated statistically significant combined constraints to differential rotation between the scaphoid and lunate. The greatest yield strength was found in the dorsal region (260.3 N +/- 118.1 N), followed by the palmar region (117.9 N +/- 21.3 N) and the proximal region (62.7 N +/- 32.2 N).

Adult↗

PubMed1999

Primary neoplasms of the carpal bones.

Primary neoplasms of the carpal bones are rare. We found 44 primary tumors of the carpal bones of 26,800 bone neoplasms (prevalence, 0.16%). Original histologic slides and original radiographs were reviewed in 36 and 29 cases, respectively. Thirty-eight tumors (86%) were benign; 6 (14%) were malignant. The average patient age was 35 years. Benign lesions were diagnosed at a younger age (32 years) than malignant lesions (58 years). Benign tumors occurred more frequently in males (23 of 38 patients); the 6 malignant lesions were equally distributed by gender (3 males and 3 females; 95% confidence interval, 11.8-88.2). The most common tumor was osteoid osteoma (11 cases); the most common malignant neoplasm was hemangioendothelial sarcoma (3). The most common locations were the scaphoid (13 cases) and capitate (10), which together accounted for 52% of all neoplasms. Tumors were identified in every carpal bone except the trapezium. The diagnosis of tumor in a carpal bone should be considered in the undiagnosed painful wrist, especially in younger patients without imaging abnormalities.

Adolescent↗

PubMed1999

Impaction allografting with cement for revision of the femoral component. A minimum four-year follow-up study with use of a precoated femoral stem.

BACKGROUND: Cancellous impaction allografting with cement for revision of the femoral component has conventionally been performed with a polished, tapered implant, which was designed to allow subsidence of the component. However, subsidence has been associated with pain in the thigh, dislocation of the hip, and revision of the component. This prospective study tested the hypothesis that good clinical results can be achieved--without subsidence of the component--with use of impaction allografting and a precoated, collared, straight stem for difficult femoral revisions. METHODS: Twenty-nine patients had revision of the femoral component with use of impaction allografting with cement and a Harris Precoat stem. Impaction allografting was performed when loss of metaphyseal and diaphyseal bone precluded revision with more straightforward techniques or when reconstitution of bone was considered a specific goal of the reconstruction (as was sometimes the case with revision of the component in younger patients). The patients were followed prospectively and were evaluated with use of the Harris hip score and serial radiographs. The patients were followed for a minimum of four years (mean, sixty-three months), except for four who died. RESULTS: Four patients died before the minimum four-year follow-up period had elapsed; all four had the prosthesis in place at the time of death. The Harris hip scores improved from a preoperative mean of 54 points (poor) (range, 21 to 91 points) to a mean of 87 points (good) (range, 41 to 100 points) at the time of the most recent follow-up. Kaplan-Meier survivorship analysis, with aseptic loosening as the end point, was 92 percent (95 percent confidence interval, 82 to 100 percent) at six years; one additional hip failed because of a hematogenous infection at seventy-three months postoperatively, for an overall failure rate of 12 percent (three of twenty-five patients) at the time of the most recent follow-up. Two hips needed a repeat revision; one was revised because of subsidence of the stem with recurrent osteolysis and the other, in a patient who had hemodialysis, because of late sepsis. A third femoral component subsided and failed but was not revised. Radiographic evidence of bone-stock reconstitution was observed in six (29 percent) of the twenty-one patients for whom radiographs were available. As in other series of patients managed with impaction allografting, the complication rate was high; excluding the revisions, three reoperations were performed, and six patients had either intraoperative femoral fracture or perforation necessitating cerclage wiring or cortical strut allografting and cerclage wiring at the time of the procedure. There were six nonunions in eighteen patients who had been operated on with a transtrochanteric approach. CONCLUSIONS: Difficult revisions of the femoral component with use of impaction allografting and a precoated stem provided satisfactory clinical and radiographic results at the time of intermediate-term follow-up. However, the high rate of complications in our series led us to refine our indications for the procedure.

Adult↗

PubMed1999

High rate of failure of allograft reconstruction of the extensor mechanism after total knee arthroplasty.

BACKGROUND: Disruption of the extensor mechanism is an uncommon but devastating complication of total knee arthroplasty. Several techniques for reconstruction of the extensor mechanism after total knee arthroplasty have been reported, but we do not know of any study in which the results of one group's method were corroborated by a second group using the same technique. In the present series, we evaluated the results of reconstruction of the extensor mechanism with use of allograft according to the method described by Emerson et al. METHODS: Seven reconstructions of the extensor mechanism with use of a bone-tendon-bone allograft were performed with the technique of Emerson et al. in six patients. The patients were evaluated before and after the operation. The knee score according to the system of The Hospital for Special Surgery, evidence of an extensor lag, use of walking aids, and the ambulatory status of each patient were recorded. The patients were also asked about, and the medical records were reviewed for, episodes of falling related to weakness of the quadriceps after the reconstruction. The mean duration of follow-up was thirty-nine months (range, six to 115 months). As these reconstructions often fail early, the minimum duration of follow-up was six months. RESULTS: All seven reconstructions were rated as clinical failures on the basis of a persistent or recurrent extensor lag of more than 30 degrees. All but one patient needed an assistive device full time for walking, and four patients (five knees) had at least one documented episode of falling that was due to giving-way of the affected knee. Four of the reconstructions were revised; one revision was performed with use of another extensor mechanism allograft and three were performed with use of a medial gastrocnemius rotation flap. The other three clinical failures had not been revised at the time of writing. At the time of the most recent follow-up (or at the time of revision of the extensor reconstruction), the mean extensor lag was 59 degrees and the mean knee score was 52 points (a poor result). CONCLUSIONS: Undertensioning of the allograft reconstruction at the time of the operation and attenuation of the allograft both may have played a role in the inability of the patients to regain active extension of the knee postoperatively. Alternative techniques for reconstruction of the extensor mechanism or modifications of this technique should be considered in the treatment of this difficult problem.

Accidental Falls↗

PubMed1999

The fate of stable cemented acetabular components retained during revision of a femoral component of a total hip arthroplasty.

BACKGROUND: The decision as to whether to revise or retain a well fixed cemented acetabular component during revision of a femoral component is especially difficult; the rate of loosening of cemented acetabular components is high, whereas that of porous-coated acetabular components inserted during revision is low. However, removal of a well fixed cemented acetabular component can result in increased operative morbidity and cost and in loss of acetabular bone. Data that can be used to predict the long-term survival of retained well fixed cemented acetabular components are therefore needed. METHODS: We studied the five to thirteen-year clinical and radiographic results in a group of twenty-six consecutive patients in whom a well fixed cemented acetabular component had been retained during revision of a femoral component. Typical demographic data on the patients and information about the components were recorded, and the cemented acetabular components were graded as A through F, according to the system of Ranawat et al., at the time of the femoral revision. The average duration of follow-up was 8.4 years (range, 5.0 to 12.7 years). No patient was lost to follow-up. RESULTS: Four acetabular components (15 percent) had progressive radiolucency (at forty-eight, forty-eight, fifty-nine, and seventy-five months after the femoral revision) and were considered radiographically loose despite not being associated with symptoms. All four components were graded as either E or F at the time that they were retained during the femoral revision; radiographic loosening was significantly related to these two grades (p < 0.01). No acetabular component with a grade of A, B, C, or D loosened. The components that loosened had been in vivo for a relatively shorter, as opposed to longer, duration before the femoral revision compared with the components that did not loosen (p < 0.05). CONCLUSIONS: Retention of the well fixed cemented acetabular components was associated with good clinical results but with a 15 percent rate of loosening. Revision of a cemented acetabular component solely on the basis of the duration that it was in vivo or whether a previous revision had been done does not appear to be warranted. Our findings suggest that acetabular components with a grade of A, B, C, or D at the time of a femoral revision may be retained, as these components continued to function at the time of the five to thirteen-year follow-up in the current study.

Acetabulum↗

PubMed1999

Intra-articular fractures of the distal aspect of the radius.

Intra-articular distal radius fractures are a heterogeneous group of injuries with different fracture patterns. The existing classification systems are helpful for describing the fractures but not for assessing their stability or for deciding which surgical approach to use. Patients who have a fracture with at least 1.0 mm of displacement of the articular surface may benefit from open surgical treatment. Improved diagnostic imaging with CT is helpful for fracture classification and surgical planning. The options for surgical treatment include limited open reduction and internal fixation, arthroscopically assisted internal fixation, and open reduction and internal fixation. The surgical approach is determined on the basis of the initial displacement of the fracture. Patients who have a displaced fracture of the volar rim may benefit from a volar approach; those who have a dorsally displaced fracture, from a dorsal approach; and those who have an impacted fracture such as a die-punch fracture, from a dorsal approach that provides better visualization of the articular surface. The long-term functional outcome is determined in part by the severity of the fracture as defined by the amount of comminution, the initial severity of displacement, and the number of fracture fragments. The accuracy of the reconstruction of the articular surface, with the goal of establishing congruency to within 1.0 mm, is also important in order to minimize the risk of late osteoarthrosis. Of all of the extra-articular parameters, restoration of the length of the radius is the most important for enhancing recovery of motion and grip strength and for preventing problems involving the distal radioulnar joint--the so-called forgotten joint in distal radial fractures.

Arthroscopy↗

PubMed1999

Microvascular reconstruction of the traumatized thumb.

Microvascular reconstruction of the thumb is technically exacting and requires a firm grasp of anatomic variations of toe blood supply. Careful preoperative planning and meticulous microsurgical technique result in a low primary failure rate and maximize functional and aesthetic results.

Humans↗

PubMed1999

Arthroscopic anatomy of the wrist and distal radioulnar joint.

A thorough and accurate understanding of the gross and arthroscopic anatomy of the wrist and distal radioulnar joints is a prerequisite for effective arthroscopy. This article describes the surface anatomy of the radiocarpal, midcarpal, and distal radioulnar joints, and provides a detailed review of the gross and arthroscopic features of the ligaments of the wrist and distal radioulnar joints. The article is written in a manner that allows the arthroscopist to perform a comprehensive survey of the entire wrist and distal radioulnar joint in a systematic fashion, with correlation to the extra-articular gross anatomy of those structures observed within the joint.

Arthroscopy↗

PubMed1999

Unicompartmental knee arthroplasty. Clinical experience at 6- to 10-year followup.

Sixty-two consecutive cemented modular unicompartmental knee arthroplasties in 51 patients were studied prospectively. At surgery, the other compartments had at most Grade 2 chondromalacia. The average age of the patients at arthroplasty was 68 years (range, 51-84 years). One patient was lost to followup and 10 died with less than 6 years followup. The average followup of the remaining 51 knees was 7.5 years (range, 6-10 years). The preoperative Hospital for Special Surgery knee score of 55 points (range, 30-79 points) improved to 92 points (range, 60-100 points) at followup; 78% (40 knees) had excellent and 20% (10 knees) had good results. The mean range of motion at followup was 120 degrees with 26 knees (51%) having range of motion greater than 120 degrees. One patient underwent revision surgery for retained cement, one patient underwent knee manipulation, and one patient underwent revision surgery at 7 years for opposite compartment degeneration and pain. Radiographically, 26 knees (51%) had at least one partial radiolucency. There were no complete femoral radiolucencies, but there were three complete tibial radiolucencies, all less than 2 mm. No component was loose as seen on radiographs. At final followup, five of the opposite compartments (10%) and three of the patellofemoral joints (6%) had some progressive radiographic joint space loss; this was less than a 25% loss in all but one knee component that was revised. At 6- to 10-years followup, cemented unicompartmental knee arthroplasty yielded excellent clinical and radiographic results. The 10-year survival using radiographic loosening or revision as the end point was 98%. Using stringent selection criteria, unicompartmental knee replacement can yield excellent results and represents a superb alternative to total knee replacement.

Aged↗