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.     

Design of hypoxia-targeting radiopharmaceuticals: selective uptake of copper-64 complexes in hypoxic cells in vitro

A freehand technique of patellar resurfacing using anatomic references was prospectively evaluated. This technique utilizes an osteotomy beginning at the inferior pole of the patella just posterior to the insertion of the patellar tendon and is carried proximally posterior to the insertion of the quadriceps tendon. Evaluation of 55 total knee arthroplasties in 41 patients showed an average restored patellar thickness within 0.1 mm. The overall patellar thickness was restored to within 1 mm of its preoperative thickness in 50 (91%) of 55 knees. Patellar tilt was equal to or less than 4 degrees in 42 (89%) of 47 arthroplasties evaluated radiographically. The patellar thickness averaged 17.9 mm, well above the critical value of 15 mm reported in the literature.     

Distal realignment of the patellar tendon to correct abnormal patellar tracking

Between January 1980 and January 1994, 31 knees required distal realignment of the extensor mechanism to treat lateral patellar subluxation that could not be corrected with lateral patellar release and vastus medialis advancement during total knee arthroplasty. Fifteen had a preoperative valgus angle of more than 12 degrees, and 16 were undergoing revision total knee arthroplasty. Ten knees had a modified Roux-Goldthwait procedure, 18 had medial tibial tubercle transfer, and three had medial transfer of the medial 1/2 of the patellar tendon. The length of followup ranged from 2 to 16 years. No late patellar subluxations or dislocations have occurred in any of these cases. Three cases of medial tibial tubercle transfer had hematomas develop, with two requiring surgical evacuation; one of these developed a late infection. No fractures or displacements of the tubercle fragment have occurred. No significant patellar complications have occurred in those patients who underwent the modified Roux-Goldthwait procedure or the medial transfer of the medial 1/2 of the patellar tendon. One year after surgery, the mean knee flexion was 113 degrees, four knees had a flexion contracture of 5 degrees, and none had a quadriceps lag.     

External tibial torsion: an underrecognized cause of recurrent patellar dislocation

Seventeen patients (18 knees) with recurrent patellar dislocation were identified with increased quadriceps angles secondary to excessive isolated external tibial torsion. Traditional realignment procedures attempted in these knees were unsuccessful because of failure to align the biomechanical axis of the extensor mechanism. Derotational osteotomies of the tibia just proximal to the patella tendon insertion were used to reduce the quadriceps angle to within normal limits to improve the biomechanics of the extensor mechanism. Seventeen (94%) knees were available for clinical and subjective followup at an average of 25 months (range, 1-3.2 years). Overall, 13 of the 17 knees were graded as good to excellent (76%). Five of the 17 patients also had well established anterior knee pain in addition to recurrent dislocation and were treated with a combined derotational and Maquet type osteotomy, with 4 patients obtaining a good to excellent result. Knees that subjectively and functionally demonstrated less painful symptoms preoperatively were associated with excellent results. Poor outcomes were associated with knees that were operated on multiple times.     

In vitro synthesis and characterization of a cartilaginous meniscus grown from isolated temporomandibular chondroprogenitor cells

Between 1984 and 1991, 57 patients with diagnosis of an acute or recurrent patellar dislocation were treated operatively using proximal realignment with vastus medialis transfer and lateral release (Insall operation). A total of 45 patients (15 with acute and 30 with recurrent patellar dislocation) were reviewed at an average follow-up of 6.5 years (2-9.6 years). The average age at injury was 21.5 years, with a predominance of female patients. Follow-up examination included routine knee examination, clinical review using the modified knee scoring scale of Larsen and Lauridsen, sports activity level and subjective satisfaction. Radiographics from 27 patients (60%) were evaluated. One patient from each group suffered recurrence of patellar dislocation. All patients had stable knee joints and a full range of motion. There was no statistical difference in the pre- and postoperative sports activity level in both groups. Three patients (19.9%) with acute patellar dislocation and seven patients (23.3%) with recurrent patella dislocation had excellent results using the Larsen and Lauridsen score scale. Ten patients (66.6%) with acute and 12 (39.9%) with recurrent dislocation had good results. One patient with recurrent patellar dislocation had a fair result. Subjective evaluation revealed the operative result in 93% of cases as very good, good or satisfactory. Patellofemoral osteoarthritis was seen in 11 (40.7%) of 27 patients. Our results show good clinical results for the treatment of acute patellar dislocation in young, active patients with the proximal realignment procedure. The recurrence rate of patellar dislocation can be reduced for acute and recurrent patellar dislocation. Subjective satisfaction with this procedure is rated very good.     

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.     

Revision knee arthroplasty with patella replacement versus bony shell

A study was undertaken to assess the clinical results of revision total knee arthroplasty in which an unresurfaced bony shell was left after removing a patellar component versus those in which a patellar component was implanted. Followup was obtained in 123 of 130 consecutive revision total knee replacements (94%) from three centers. In 21 knees a shell of patellar bone was left and 92 knees had a patellar component in place. Ten patients had a patellectomy and were excluded from consideration. The group with the bony shell had a lower postoperative knee score but the preoperative Knee Society clinical score was significantly lower as well in this group of patients. Compared with the group of patients with the patellar component in place, the group of patients with knees left with a bony shell had a significantly higher percentage of patients who had difficulty using stairs, a higher percentage of patients who were not satisfied with their surgery, and a higher percentage of patients who rated their surgery as unsuccessful in returning them to normal daily activities. When a patellar component was not able to be implanted in revision total knee arthroplasty, a lower quality result was observed.     

Cytostatic treatment of patients with advanced non-small cell lung cancer

Complications of patellar resurfacing in total knee arthroplasty have rekindled the interest of many surgeons in patellar retention. In a prospective study 20 randomly selected patients of 40 underwent patellar resurfacing in combination with their total knee arthroplasty. The other 20 patients were left with an unresurfaced patella. Within 24 months of follow-up, the advantages of patellar resurfacing could be seen according to the Knee Society Score. Especially in advanced osteoarthritis of the knee joint, the patients achieved better scores in climbing stairs and in function. The superior functional results are arguments for patellar resurfacing, at least in knees with advanced osteoarthritis.     

The effect of femoral component position on the kinematics of total knee arthroplasty

In a laboratory study using seven fresh-frozen anatomic specimen knees, the effect of total knee arthroplasty on the three-dimensional kinematics of the patella, femur, and tibia were measured. Experiments were performed in the intact knee, after division of the anterior cruciate ligament (ACL), after total knee arthroplasty, and after 10 degrees internal rotation, 10 degrees external rotation, 5-mm medial shift, and 5-mm lateral shift of the femoral component on the femur. The presence of a high lateral ridge on the anterior surface of the femoral component effectively prevented patellar subluxation or dislocation, but displaced and tilted the patella medially. Internal rotation or medial displacement of the femoral component exaggerated this medial patellar displacement and shift. External rotation of the femoral component corrected it, except at flexion angles greater than 100 degrees, where the femur was shifted medially on the tibia and externally rotated 15 degrees. This combination produced a net 10-mm medial displacement of the patella relative to the tibia at 120 degrees knee flexion. Lateral placement of the femoral component compensated for the effect of the high lateral ridge and allowed more normal patellar tracking while allowing tibiofemoral motions similar to those seen after sectioning of the ACL. The kinematics of the patellofemoral and tibiofemoral joints were not reproduced with a total knee prosthesis that sacrifices the ACL. When using a prosthesis with a high lateral ridge, lateral placement of a femoral component prevented patellar dislocation and allowed patellar tracking patterns similar to those seen in the intact knee without further altering tibiofemoral motions.     

Dislocation following primary posterior-stabilized total knee arthroplasty

From 1981 through 1991, 3,032 primary total knee arthroplasties were performed using the Insall-Burstein Posterior Stabilized Condylar Prosthesis (IB-I, IB-II, and IB-II modified) (Zimmer, Warsaw, IN). Fifteen posterior dislocations occurred: 4 with the IB-I system occurring 2 or more years after surgery, 10 with the IB-II system (8 occurring 6 months after surgery and 2 occurring 2-3 years after surgery), and 1 with the IB-II modified system occurring 9 months after surgery. Statistically significant differences for the rate of dislocation between both the IB-I and IB-II modified arthroplasties versus the IB-II arthroplasties were found (P < .001). In an attempt to identify a cause for these dislocations, the authors retrospectively assessed the 15 dislocated cases with respect to sex, age, weight, height, preoperative and postoperative Hospital for Special Surgery scores, preoperative and postoperative alignment, preoperative versus postoperative reconstruction dimensions, patellar thickness and height, and postoperative flexion and compared the results with those patients who did not experience dislocation. Possible etiologies and mechanisms of dislocation were sought. There were no significant differences between the control and study groups for any variable assessed, with the exception of postoperative flexion, which averaged 118 degrees for the study group and 105 degrees for the control group (P < .001). Conservative management was successful in 11 cases. In September 1988 the IB-II system was introduced; modification of the tibial insert was made in January 1990.(ABSTRACT TRUNCATED AT 250 WORDS)     

Patellar component resection in revision and reimplantation total knee arthroplasty

Between 1979 and 1995, 34 knees in 31 patients had a revision or reimplantation total knee arthroplasty in which the patellar component could not be reinserted. The patellar bone stock in each of those cases was compromised markedly and precluded adequate prosthetic fixation. The mean followup after the revision operation was 3.5 years (range, 2-14 years). The Knee Society knee score improved from a mean of 59 points preoperatively to a mean of 75 points postoperatively. The function score improved from a mean of 46 points preoperatively to a mean of 69 points postoperatively. Complications occurred in five patients: one patient sustained a patellar fracture that required no additional treatment; one experienced intermittent episodes of patellar subluxation; one had a recurvatum deformity develop and was treated with a brace; one had persistent knee stiffness and had four manipulations; and one patient had an extensor lag of 30 degrees develop. Twenty-six patients were satisfied with the results of their revision operations and five were dissatisfied. Ten patients had persistent knee symptoms referable to the patellofemoral articulation: mild pain in three; moderate pain in six; and severe pain in one. This study suggests that resection of the patellar component during revision or reimplantation total knee arthroplasty may be a reasonable approach for patients with markedly compromised patellar bone stock; however, mild or moderate anterior knee pain can be expected to persist in as much as 1/3 of these patients.     

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.     

A comparison of isokinetic strength testing and gait analysis in patients with posterior cruciate-retaining and substituting knee arthroplasties

Fourteen patients with a posterior-stabilized prosthesis in one knee and a posterior cruciate-retaining prosthesis in the contralateral knee and both scoring good or excellent on the Hospital for Special Surgery (HSS) knee scale were evaluated by isokinetic muscle testing and comprehensive gait analysis at a mean follow-up of 98 months after arthroplasty. The average HSS knee score (93 points) and the average Knee Society score (94 points) were the same for the cruciate-retaining and posterior-stabilized knees. No differences were noted between the cruciate-retaining and the posterior stabilized knees with respect to isokinetic muscle testing parameters (peak torque, endurance, angle of peak torque, and torque acceleration energy) for both quadriceps and hamstrings. No significant differences were found between the cruciate-retaining and the posterior-stabilized knees with regard to gait parameters, knee range of motion, and electromyographic waveforms during level walking and stair climbing. Cruciate-retaining and posterior-stabilized total knee prostheses perform equally well during level gait and stair climbing.     

Investigation of the usefulness of CYFRA 21-1 as a tumor marker in squamous cell carcinomas of the head and neck

Compressive contact stress between the patella and the anterior femur and between the quadriceps tendon and anterior femur was measured before and after total knee arthroplasty in 5 cadaver knee specimens using a digital electronic sensor. Contact stresses were measured in the normal knee and after total knee arthroplasty with an unresurfaced patella, a dome-shaped patella, and a conforming patella. Patellofemoral contact stresses did not change significantly after total knee arthroplasty when the patella was not resurfaced, but they increased significantly after the patella was resurfaced with both the dome-shaped and the conforming components. The conforming patella had the highest contact stresses because it tilted at flexion angles greater than 90 degrees and applied load to a small area on the superior portion of the patellar component. The conforming patella markedly decreased tendofemoral contact force because the thicker superior pole of the patella tented the quadriceps tendon at flexion angles greater than 120 degrees. This further increased patellofemoral contact force in deep knee flexion.     

Characteristics of impaired awareness after traumatic brain injury

The condylar constrained total knee arthroplasty was performed on 29 patients undergoing 33 procedures and were reviewed clinically and radiographically at an average follow-up of 5 years (range, 2-10 years). There were 21 women and 8 men. The average age at the time of surgery was 70 years (range, 32-84). Of the 16 knees that were revision total knee arthroplasties, 8 had a previous infected total knee arthroplasty, and 17 knees had severe deformities requiring the use of the condylar constrained prosthesis. The patients were rated according to the Knee Society clinical and radiological evaluation protocol. Measurements of femoral and tibial component position were obtained as well as femoral tibial angle, patella position, and cement bone radiolucencies. All clinical measurements were made by an independent physical therapist. Clinical results revealed an improvement from an average preoperative knee score of 38 points to an average postoperative score of 86 points. The clinical results for 19 (58%) knees were excellent, 8 (24%) had a good result, 1 (3%) was fair, 2 (6%) were poor, and 3 (9%) were failures. The patients' average functional levels increased from 24 to 58. The final average flexion was 96 degrees. Three knees have been revised (9%). One was revised for recurrent infection, one for periprosthetic fracture, and one for mechanical loosening of the tibial component. There were no other knees with evidence of radiologic loosening. We conclude that the condylar constrained total knee prosthesis provides an acceptable solution for revision and complex primary total knee replacements at an intermediate follow-up term of 5 years.     

Complications following total knee replacement

Forty-two months follow-up examinations on 30 total knee arthroplasties revealed the following significant complications: phlebothrombosis, 13 knees (46%); pulmonary embolism 3 patients (11%); asymptomatic loosening, 8 knees (11.4%); symptomatic loosening, 3 knees (4.8%); superficial infections, 4 knees (5.4%); deep infections, 4 knees (5.4%); peroneal palsy, 3 patients (4.3%). Early detection of thrombophlebitis by 125I fibrinogen scan and possible aspirin prophylaxis were evaluated. In view of the limited number of encouraging results, e.g. excellent 58.6 per cent; good 28.5 per cent; fair 5.4 per cent and poor 7.1 per cent, caution is advocated until extensive time elapses for more clinical experience with total knee arthroplasty.     

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.     

Metaphase karyotypes of Anopheles of Thailand and Southeast Asia: IV. The Barbirostris and Umbrosus species Groups, subgenus Anopheles (Diptera: Culicidae)

Based on an analysis of patellar complications during total knee arthroplasty, the authors report the conclusions of the most important studies in the literature as to whether or not the patella should be prosthetized. In particular, several important parameters to be taken into consideration before performing patellar prosthetization are discussed: the conditions of the cartilage and of the patellar bone, preoperative clinical symptoms, age, habits, body weight of the patient. The results of 50 Miller-Galante prostheses implanted between January 1989 and September 1993 is reported. The patella was prosthetized in 40% of the cases; there were no fractures or vascular necroses, nor was there breakage or detachment of the prosthetic button. Patellar pain was manifested in 5 cases (10%), 2 of which with a prosthetized patella, including 1 case of external dislocation and 1 case of breakage of the patellar tendon; another case of external dislocation, in a non-prosthetized patella, was clinically asymptomatic; pain was manifested after delay in wound healing in 2 cases. Only one patient with breakage of the patellar tendon was submitted to further surgery. The authors conclude that in light of the numerous studies published prosthetization of the patella may offer overall better clinical results, but they advise that indications should be carefully evaluated for each individual case, and that details in surgical technique should be observed (correct execution of bone resection and of lateral release when necessary, preservation of Hoffa pad, accurate hemostasis).     

Subtrochanteric femoral shortening osteotomy in total hip arthroplasty for high-riding developmental dislocation of the hip

A surgical technique, which uses a transverse osteotomy, for subtrochanteric femoral shortening and derotation in total hip arthroplasty for high-riding developmental dislocation of the hip is described. Anteversion is set by rotating the osteotomy fragments, and torsional stability is augmented with allograft struts and cables when indicated. Eight patients with 9 total hip arthroplasties were followed for an average of 43 months (range, 24-84 months). Good to excellent results were obtained in 87% of patients (7 of 8). Eight of 9 osteotomies (89%) demonstrated radiographic evidence of healing at an average of 5 months. One patient had an asymptomatic nonunion of the osteotomy site but still had a good overall clinical result. Another patient suffered fatigue failure of a distally ingrown porous device, which necessitated revision total hip arthroplasty 18 months after surgery. Subtrochanteric osteotomy in total hip arthroplasty for developmental dislocation of the hip allows for acetabular exposure and diaphyseal shortening while facilitating femoral derotation. Furthermore, proximal femoral bone stock is maintained and some of the potential complications of greater trochanteric osteotomy may be avoided.     

Patellar tracking after total knee arthroplasty. The effect of tibial tray malrotation and articular surface configuration

The effect of total knee arthroplasty (TKA) with neutrally aligned and malrotated tibial trays was studied in five fresh anatomic specimen knees. Patellar shift, tilt, and rotation, and the rotational position of the tibia were measured in normal knees and after TKA with the Ortholoc Modular knee system. Both semiconstrained and unconstrained articular surfaces were assessed in the neutral position and at anatomic, 15 degrees internal, and 15 degrees external rotation of the tibial tray. After TKA, the patellae shifted slightly medially in the early phase of knee flexion because the anterior lateral flange of the femoral component was longer than the lateral trochlea of the femur and because the tibia rotated internally. The raised lateral flange on the femoral component tilted the patella medially at full extension after TKA. The semiconstrained tray allowed minimal tibial rotation because of its articular configuration. As much as 15 degrees malrotation of the unconstrained tibial tray did not affect patellar tracking. The semiconstrained tibial tray in the neutral position had almost the same patellar tracking as the unconstrained tray, but at 15 degrees external rotation, the semiconstrained tray internally rotated the tibia, leading to medial shift of the patella. Although 15 degrees internal rotation caused external rotation of the tibia, the patella did not shift as much laterally, despite the increase in the Q angle.