Semiconstrained total elbow arthroplasty

Diminution of elbow function may be both embarrassing and severely disabling, especially in patients with multiple arthritic joints. Over the past century, multiple techniques of soft tissue reconstruction of the elbow have been advocated. In general, they do not compare well with total elbow arthroplasty. Arthrolysis has often resulted in little improvement of elbow motion and interposition arthroplasty to instability. Synovectomy may however offer satisfactory relief of disability for the rheumatoid elbow provided that initially there is little evidence of joint destruction. The major problem with rigidly linked total elbow arthroplasty has been a high incidence of prosthetic loosening. Biomechanical analysis has shown that high moments tend to disrupt the osseousmethacrylate junction in the humoral medulary canal. Development of a semi-constrained total elbow prosthesis transfers the developed stress to the collateral soft tissues and reduces prosthetic loosening to approximately 3 per cent. This is about one-tenth of the incidence of loosening of the hinge type arthroplasty. This reduction in prosthetic loosening has been coupled with excellent gains in flexion and estension. However, improvement in forearm rotation has not been predictable, especially in elbows exhibiting preoperative fusion or fibrous ankylosis. Though the semi-counstrained total elbow has only been generally available for 3 years, a review of these results justifies its continued use for elbow reconstruction.     

Radiohumeral arthrodesis for salvage of failed total elbow arthroplasty

Ulnohumeral arthrodesis is the standard technique for elbow fusion. The geometry and surface area of the distal humerus and proximal ulna enhance the chances of fusion while maintaining some wrist motion. A case of a patient with multiple failed elbow procedures in which the standard ulnohumeral fusion was not possible is presented. A radiohumeral arthrodesis was performed in an attempt to obtain a stable, nonpainful elbow. After complete healing of the fusion, the patient was able to use the arm for most functions. This technique is presented as an option for salvage failed elbow arthroplasty in the face of significant bone loss.     

Life expectancy after total hip arthroplasty

A total of 3,807 patients undergoing total hip arthroplasty (THA) between the years 1970 to 1995 were evaluated for mortality. Patient age groups were designated in 10-year intervals as follows: age <40; 41-50; 51-60; 61-70; 71-80; age >80. The life expectancy estimate of the patients with THA was calculated by the Kaplan-Meier method, and that of the normal population was obtained from standard life-tables. Statistical significance was evaluated using 95% confidence limits. A significant difference in life expectancy was found in patient age groups >60 (61-70, 71-80, >80) demonstrating significantly higher survival rates among THA patients when compared with the normal population.     

Immediate weightbearing after uncemented total hip arthroplasty

Radiographic subsidence of the femoral prosthesis and clinical results after unilateral and simultaneous bilateral uncemented total hip arthroplasty were compared. Patients who had bilateral total hip arthroplasty began weight-bearing as tolerated on both lower extremities the day after surgery. Patients who had undergone unilateral total hip arthroplasty were maintained at 10% weightbearing on the operative limb for 6 weeks after surgery. Patients in both groups were matched for age, gender, and weight. Minimal followup was 2 years. There was no difference between the two groups in terms of clinical results. Radiographic assessments were performed immediately after surgery, 6 weeks after surgery, and again at 2 years after surgery. Radiographs were reviewed by a single observer and analyzed with a digitized data recorder. Increased subsidence of the femoral prosthesis within the bilateral group was found at 6 weeks. The mean subsidence of the femoral prosthesis at 6 weeks for the bilateral total hip arthroplasty group was 0.86 mm (range, 0.18-2.60 mm) and for the unilateral group was 0.39 mm (range, 0.07-1.46 mm). However, subsidence occurring between 6 weeks and 2 years averaged 0.50 mm (range, 0.09-1.10 mm) for the bilateral group and 0.54 mm (range, 0.03-0.99 mm) for the unilateral group. This difference was not significant. At the 2-year followup, all femoral prostheses in both groups appeared radiographically stable with evidence of bone ingrowth and no indications of loosening. Thus, immediate weightbearing after bilateral total hip arthroplasty in this study resulted in more initial subsidence (during the first 6 weeks after surgery) of the femoral prosthesis but did not preclude the prosthesis from becoming stable and achieving bone ingrowth. Patients in both groups obtained satisfactory clinical results. Because initial stability and bone ingrowth are factors influenced by prosthesis design, the results of this study may not be applicable to all implants.     

Posttraumatic elbow arthritis and arthroplasty

Elbow contractures without significant articular injury can be treated with soft-tissue procedures, such as joint capsular releases, resection of heterotropic ossification, and joint debridement. Elbows with significant intra-articular injuries or posttraumatic arthritis require some form of joint reconstruction, such as a distraction arthroplasty, interposition arthroplasty, or implant replacement arthroplasty. With a better understanding of the surgical indications for elbow arthroplasty, improvements in surgical technique, improvements in elbow implants, and increased surgical experience, the results of implant arthroplasty for the posttraumatic elbow continue to improve.     

The elbow joint and its total arthroplasty. Part II. Finite element study

The stresses in various sections of two-dimensional models of the elbow joint, without and with a prosthesis (the humeral component of a total elbow prosthesis), were obtained using the finite element analysis method. Three parameters were varied: type of applied load; method of fixation of the prosthesis to the contiguous bone; and shape of the head of the prosthesis. The results are discussed with particular reference to stress shielding and overload in the cortical and cancellous bones, respectively, and a qualitative comparison between the present values and those given by previous workers who used three-dimensional models. Comments are made regarding the clinical implications of the results.     

Perioperative bladder management after primary total hip arthroplasty

A retrospective review of 95 consecutive primary total hip arthroplasty patients was performed to assess the clinical outcome of two postoperative bladder management protocols. The first 49 patients (group 1) were treated with a pro re nata straight catheterization protocol. The next 46 patients (group 2) were treated with an indwelling catheterization protocol. There were no differences between the groups with respect to sex or age. The patients in group 2 had significantly lower incidences of urinary retention (P < .0005) and bladder distention (P < .0005) than those in group 1. Preoperative systemic diseases and urologic symptoms did not correlate with the occurrence of postoperative urinary retention or bladder distention. There were no infections in group 1. In group 2, one patient (2%) had bacteriuria and one patient (2%) had a urinary tract infection (P > .1). This trend of increased contamination in the catheterization group may be related to a mean catheterization duration of 72 hours.     

Malrotation causing patellofemoral complications after total knee arthroplasty

Thirty patients with isolated patellofemoral complications after total knee arthroplasty were compared with 20 patients with well functioning total knee replacements without patellofemoral complications. The epicondylar axis and tibial tubercle were used as references on computed tomography scans to measure quantitatively rotational alignment of the femoral and tibial components. The group with patellofemoral complications had excessive combined (tibial plus femoral) internal component rotation. This excessive combined internal rotation was directly proportional to the severity of the patellofemoral complication. Small amounts of combined internal rotation (1 degree-4 degrees) correlated with lateral tracking and patellar tilting. Moderate combined internal rotation (3 degrees-8 degrees) correlated with patellar subluxation. Large amounts of combined internal rotational (7 degrees-17 degrees) correlated with early patellar dislocation or late patellar prosthesis failure. The control group was in combined external rotation (10 degrees-0 degree). The direct correlation of combined (femoral and tibial) internal component rotation to the severity of the patellofemoral complication suggests that internal component rotation may be the predominant cause of patellofemoral complications in patients with normal axial alignment. The epicondylar axis and tibial tubercle are reproducible landmarks which are visible on computed tomography scans and can be used intraoperatively. Using this computed tomography study can determine wether rotational malalignment is present and thus, whether revision of one or both components may be indicated.     

Revision total knee arthroplasty after failed unicompartmental knee arthroplasty or high tibial osteotomy

A retrospective matched-pair comparative analysis was done between 30 total knee arthroplasties following failed high tibial osteotomies and 30 total knee arthroplasties following failed unicompartmental knee arthroplasties. The groups were matched according to age, gender, type of prosthesis, primary disease, and length of followup. A minimum followup of 2 years was required for inclusion in the study, and the average followup was 3.8 years (range, 2-9 years). The Knee Society Knee Score for the high tibial osteotomy group was significantly higher than that for the unicompartmental arthroplasty group. More osseous reconstructions were required in the unicompartmental revisions. Difficulty with exposure was not significantly greater in the osteotomy group. Rates of component loosening were not significantly different between the groups. A failed unicompartmental knee arthroplasty and a failed high tibial osteotomy can be revised successfully to a total knee arthroplasty. The results confirm that revisions after unicondylar arthroplasty and high tibial osteotomy are technically demanding. In this series, the results of total knee arthroplasty following unicompartmental knee arthroplasty approached but did not equal those obtained after high tibial osteotomy.     

Sacral plexopathy and sciatic neuropathy after total knee arthroplasty

While peroneal and tibial neuropathies have been described as a complication of total knee arthroplasty (TKA), a computerized literature search failed to reveal any previously reported cases of associated sacral plexopathy or sciatic neuropathy. This case report describes the diagnosis and management of a patient found to have evidence of a right sacral plexopathy and a left sciatic neuropathy, following bilateral TKA. This case suggests that these may be rare complications of TKA.     

Extensor mechanism reconstruction with an allograft after total knee arthroplasty

The authors report on a series of 15 knees in which an extensor mechanism allograft was used to treat a rupture of the patellar tendon associated with a total knee arthroplasty. Nine of the knees have greater than two-year follow-up evaluation (average, 4.1 years; range, 2.3-7 years). Postoperatively, the average flexion was 106 degrees. All but three patients achieved full passive extension. Six of the nine knees had no extensor lag. The average post-operative clinical score for the follow-up group was 78 points. Graft complications include one early graft rupture, one early quadriceps junction failure, and one patellar component loosening. One graft fractured after revision of a metal-backed patella.     

Flexion instability after primary posterior cruciate retaining total knee arthroplasty

Between 1990 and 1995, 25 painful primary posterior cruciate ligament retaining total knee arthroplasties were revised for flexion instability. These patients shared typical clinical presentations that included a sense of instability without frank giving way, recurrent knee joint effusion, soft tissue tenderness involving the pes anserine tendons and the retinacular tissue, posterior instability of 2+ or 3+ with a posterior drawer or a posterior sag sign at 90 degrees flexion, and above average motion of their total knee arthroplasty. The primary total knee arthroplasty was performed for osteoarthritis in 23 patients and rheumatoid arthritis in two patients. There were 13 male and 12 female patients and their mean age was 65 years (range, 35-77 years). Before the revision operation, Knee Society knee scores averaged 45 points (range, 17-68 points) and function scores averaged 42 points (range, 0-60 points). Twenty-two of the knee replacements were revised to posterior stabilized implants and three underwent tibial polyethylene liner exchange only. Nineteen of the 22 knee replacements revised to a posterior stabilized implant were improved markedly after the revision surgery. Only one of three knee replacements that underwent tibial polyethylene exchange was improved. After the revision for flexion instability, Knee Society knee scores averaged 90 points (range, 82-99 points) and function scores averaged 75 points (range, 45-100 points) for the 20 knees with a successful outcome. This study suggests that flexion instability can be a cause of persistent pain and functional impairment after posterior cruciate ligament retaining total knee arthroplasty. A revision operation that focuses on balancing the flexion and extension spaces, in conjunction with a posterior stabilized knee implant, seems to be a reliable treatment for symptomatic flexion instability after posterior cruciate retaining total knee arthroplasty.     

Antibody-induced arterial thromboembolism resulting in amputation after total knee arthroplasty

Heparin-induced thrombocytopenia is a rare drug reaction that can be associated with thrombotic complications leading to myocardial infarct, stroke, or ischemic loss of a limb. Because of the broadening indications of low-molecular-weight heparin use, the current emphasis on ambulatory care, and the difficulty in clinical diagnosis and treatment of this drug reaction, heparin-induced thrombocytopenia is the most important allergic drug reaction that physicians must manage. An antibody-mediated drug reaction to low-molecular-weight heparin that resulted in a below-knee amputation after an elective total knee arthroplasty is reported.     

Fatal pulmonary embolism after total hip arthroplasty: diurnal variations

From 1970 through 1986, a total of 18,104 Charnley low-friction arthroplasties were performed; of these, 122 deaths occurred from pulmonary embolism within 1 year of surgery. Diagnosis was confirmed by postmortem examination in 71% of cases. The exact time of the onset of the complication was recorded in 90 cases. In 74 (82%) cases, the time of collapse occurred during the 7-hour period from 9:00 AM to 4:00 PM, and in 16 (18%) cases, it occurred in the 17-hour period from 4:00 PM to 9:00 AM. The patient's activity at the time of collapse was recorded in 73 cases. Sixty (82%) were mobile, 3 were in the bathroom, and 10 (14%) were in bed. Sixty-six (70.2%) patients died within 1 hour of the onset of symptoms.     

Bone density at the proximal femur after total hip arthroplasty

Recent developments in dual xray absorptiometry have made it possible to quantify bone mineral density changes adjacent to total hip arthroplasty. Even small changes in local bone mass that are not visible with conventional radiographs can be detected using dual xray absorptiometry. Commonly there is a loss of 10% to 45% of the periprosthetic bone mass during the first years after total hip arthroplasty. Recent studies have suggested that this bone loss is not necessarily progressive and some degree of restoration of bone density around implants may occur. Current data suggest that there is active bone remodeling in the proximal femur in response to prosthetic implantation. Such response differs between different stem designs and type of fixation.     

Hinged total knee arthroplasty

Analysis of an on-going prospective study of seventy-seven hinged total knee arthroplasties in sixty-seven patients revealed that most patients had improvement in function, although major complications occurred in eighteen knees (23.4 per cent. These complications included sepsis, loosening, patellar tendon rupture, peroneal palsy, and patellar subluxation. Eight of nine knees with deep sepsis required removal of the prosthesis, and three of sixteen knees with patellar pain required realignment of the quadriceps. When prosthetic failure occurred, salvage of a functional extremity was difficult. Hinged total arthroplasty is not without its problems, and a cautious approach to its use is indicated. Whenever possible, a moderately constrained replacement arthroplasty should be considered.     

Polycentric total knee arthroplasty

Polycentric total knee arthroplasty in 56 patients provided significant relief of pain in 90.7% and a stable knee in 92.7%. Postoperative increase in range of motion averaged 13.7 degrees for all patients (18.5 degrees in rheumatoid arthritis and 8.7 degrees in degenerative arthritis). This increase in excursion is attributed to the design of the prosthesis, a vigorous postoperative rehabilitation program, and careful surgical technic. A failure rate of 12.7% was due to infection, mechanical instability and unexplained pain. Contraindications to surgery and technical recommendations are noted.     

Hybrid total knee arthroplasty

A prospective study of a hybrid total knee arthroplasty (TKA) with an uncemented femoral component and cemented tibial and patellar components was performed to combine the advantage of a press-fit femur while avoiding the problems in uncemented tibial and patellar implants. A total of 329 posterior cruciate-preserving TKA were studied at an average of 4.7 years after surgery: 84% of the knees had at most mild or occasional pain, 68% had good or excellent knee scores, and 62% could walk more than 1000 m. The function scores were 40% good or excellent in this collective, with an average age of 69.4 years at surgery. The component position and alignment were biomechanically correct. Radiolucent lines were observed regularly at the edges of the tibial and femoral components. There were no revisions for aseptic loosening. Hybrid TKA provides good results comparable to cemented TKA.