Kinematic analysis of posterior-stabilized total knee arthroplasty during standing up from and sitting down on a chair.

BACKGROUND: Total knee arthroplasty is effective to regain quality of life. Standing up from and sitting down on a chair and stair stepping motion are important in daily living. We previously reported in vivo kinematics of this implant during a stepping exercise. The purpose of this analysis was to assess in vivo knee motion during standing up from and sitting down on a chair and determine the motion pattern in patients with the unique knee prosthesis. METHODS: A total of 15 patients implanted with Bi-Surface PS were assessed during standing up from and sitting down on a chair. The Bi-Surface PS knee is a posterior-cruciate substitute prosthesis with a unique ball-and-socket joint in the mid-posterior portion of the femoral and tibial components. Patients were examined during standing up from and sitting down on a chair using a two-dimensional to three-dimensional registration technique. RESULTS: During standing up from and sitting down on a chair from minimum to 30° knee flexion, anterior femoral translation was slight. From 30° knee flexion to maximum flexion, the kinematic pattern was a medial pivot and rollback. CONCLUSIONS: This study demonstrated that the knee motion kinematic patterns observed in this study were not similar to normal knee kinematics and derived from the unique design of the Bi-Surface PS.

The Role of Complete Suprapatellar Plicae.

Shelf syndrome mainly affects younger people, often athletes. Cases of complete suprapatellar plica syndrome are rare. Arthroscopic inspection is necessary to diagnose complete suprapatellar plicae. The patients' symptoms improve after removal of the plicae. Our technique is an easy, completely arthroscopic procedure that has yielded good clinical outcomes in patients who have complete suprapatellar plicae. Although cases of complete suprapatellar plica syndrome are rare, it should be considered in patients with moderate knee pain.

In vivo kinematics of a unique posterior-stabilized knee implant during a stepping exercise.

BACKGROUND: Stair-stepping motion is important in daily living, similar to gait. Knee prostheses need to have even more superior performance and stability in stair-stepping motion than in gait. The purpose of this analysis was to estimate in vivo knee motion in stair stepping and determine if this unique knee prosthesis function as designed. METHODS: A total of 20 patients with Bi-Surface posterior-stabilizing (PS) implants were assessed. The Bi-Surface PS knee is a posterior-cruciate substitute prosthesis with a unique ball-and-socket joint in the mid-posterior portion of the femoral and tibial components. Patients were examined during stair-stepping motion using a 2-dimensional to 3-dimensional registration technique. RESULTS: The kinematic pattern in step up was a medial pivot, in which the level of anteroposterior translation was very small. In step down, the kinematic pattern was neither a pivot shift nor a rollback. From minimum to maximum flexion, anterior femoral translation occurred slightly. CONCLUSIONS: In this study, this unique implant had good joint stability during stair stepping. The joint's stability during stair stepping was affected by the design of the femorotibial joint rather than post/cam engagement or the ball-and-socket joint.

Knee Arthritis Without Other Joint Symptoms in the Elderly With Seronegative Elderly Onset Rheumatoid Arthritis.

Elderly onset Rheumatoid arthritis (EORA) has important clinical distinctions when compared with younger onset RA (YORA). In knee arthritis of elderly patients, infection, crystal-induced arthritis or EORA should be suspected if elevation of CRP in the preoperative examination and turbid joint effusion in their knee joint are found. Furthermore, if joint swelling and effusion remain after performing total knee arthroplasty (TKA), the infection after TKA, implant debris-related arthritis and EORA should be considered. However, it is difficult to diagnose patients as EORA if Rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibody (ACPA) are negative. The differential diagnosis is very important.

Gait parameters in women with bilateral osteoarthritis after unilateral versus sequential bilateral total knee arthroplasty.

PURPOSE: To compare gait parameters in women after unilateral total knee arthroplasty (TKA) versus sequential bilateral TKA to determine the need for sequential TKA. METHODS: 35 women aged 60 to 74 (mean, 70) years with bilateral varus knee osteoarthritis (OA) underwent unilateral (n=23) or sequential bilateral (n=12) TKA by a single surgeon. All patients underwent unilateral TKA; 12 patients then underwent sequential TKA after 3 to 6 months of the first TKA. Gait parameters (step length, step width, gait velocity, single support phase value, and the maximum centre of gravity ratio) were compared before and after TKA, and between patients with unilateral versus bilateral TKA. RESULTS: Patients with sequential bilateral TKA had more severe OA in their contralateral knee than patients with unilateral TKA. In patients with unilateral and sequential bilateral TKA respectively, the mean step width differed at postoperative one month (12.9 vs. 19.1, p<0.01) and 3 months (11.9 vs. 16, p=0.03), and the mean maximum centre of gravity ratio differed at postoperative 3 months (2.43 vs. 1.75, p=0.02), whereas the mean step length, mean gait velocity, and mean single support phase values did not differ significantly between groups. CONCLUSION: After unilateral TKA, contralateral TKA may not be necessary in some patients whose gait has improved.

Unusual appearance of an osteochondral lesion accompanying medial meniscus injury.

An osteochondral lesion in the knee joint is caused by a focal traumatic osteochondral defect, osteochondritis dissecans, an isolated degenerative lesion, or diffuse degenerative disease. An osteochondral lesion with a cleft-like appearance accompanying medial meniscus injury is rare without trauma. We report the case of a 13-year-old boy who complained of right knee pain and swelling, with radiographic findings of an osteochondral defect. Arthroscopic inspection showed an osteochondral lesion in the medial condyle of the femur and tibial plateau accompanying a partial medial meniscus discoid tear. Partial meniscectomy was performed, and a microfracture procedure was carried out on the osteochondral defect. The patient was asymptomatic at 2 years' follow-up. This technique is a relatively easy, completely arthroscopic procedure that spares the bone and cartilage and has yielded a good clinical outcome in a skeletally immature patient who had an osteochondral lesion with a cleft-like appearance.

Collagen expression in various degenerative meniscal changes: an immunohistological study.

PURPOSE. To examine changes in acid mucopolysaccharides and collagen expression during meniscal degeneration, tearing, and repair, using menisci excised from knee joint surgeries. METHODS. Menisci excised from 23 patients aged 15 to 80 years who underwent meniscal surgery for flap and bucket handle tears (n=11) and total knee arthroplasty (TKA) for osteoarthritis (n=12) were examined histologically. Staining images were converted to greyscale images to measure the mean grey levels, which indicated densitometry. Comparisons were made between acutely injured menisci and menisci with and without degeneration (from patients with osteoarthritis) in terms of acid mucopolysaccharides, collagen types I, II, and III expression. RESULTS. In menisci with no degeneration, acid mucopolysaccharides, collagen types I and II were expressed throughout the entire meniscus except for the circulating area. Collagen type III was intensely expressed at the exterior peripheral border and on the surface. During progression of meniscal degeneration, the expression of acid mucopolysaccharides increased, and the expression of collagen types I, II, and III decreased. In acutely injured menisci, collagen types II and III disappeared first, followed by collagen type I, resulting in the abrogation of fibre construction. CONCLUSION. In normal menisci, acid mucopolysaccharides and collagen types I, II, and III were well-balanced, and meniscal function was maintained. When the limits of repair were exceeded, the meniscus tissue deteriorated owing to the disappearance of collagen types II and III and a decrease in collagen type I, resulting in the abrogation of meniscus fabric construction.

Rotational acetabular osteotomy for habitual hip dislocation with posterior acetabular wall deficiency in patients with Down syndrome.

Hip dislocation associated with Down syndrome is relatively rare. Hip dislocation can progress to severe subluxation or habitual dislocation if the initial therapy is improperly performed. However, definitive treatment guidelines for conservative and surgical therapy for hip dislocation in patients with Down syndrome have not been established. This article describes a case of a 12-year-old girl with Down syndrome with nontraumatic habitual hip dislocation. Her hip joint was associated with acetabular dysplasia and hypoplasia of the posterior acetabular wall. Although conservative therapy was initially performed, no effects were observed. Rotational acetabular osteotomy and capsular plication were performed to reconstruct the posterior acetabular wall. No postoperative redislocation occurred, and the treatment effects were favorably sustained for 2 years. In Down syndrome, few cases of developmental dysplasia and hypoplasia of the posterior acetabular wall have been reported. In previous reports, these morphological abnormalities were rarely taken into consideration when determining the treatment strategy, and to our knowledge, no other reports demonstrate therapy involving rotational acetabular osteotomy for hip dislocation complicated with Down syndrome. Whether the acetabulum had posterior wall deficiency was thought to be important for conservative and surgical therapies in hip dislocation in patients with Down syndrome. Rotational acetabular osteotomy could be an effective surgical procedure for reconstruction of the acetabulum by posterolateral rotation of the osteotomized acetabulum.