Tight posterior cruciate ligament in posterior cruciate-retaining total knee arthroplasty: a cause of posteromedial subluxation of the femur.

Posteromedial subluxation has been reported as a mode of failure with flat-on-flat articular geometry. Medical records were reviewed to find patients who developed progressive subluxation of the femur. From a consecutive series of 2,773 primary anatomically graduated components (AGC) knees, 6 patients developed progressive posterior subluxation of the femur. The mean interval between the index total knee arthroplasty (TKA) and the diagnosis of subluxation was 4.8 years. Five cases were revised at an average of 6.2 years after index TKA. Tightness of the posterior cruciate ligament (PCL) was observed in all revised cases. Progressive posterior subluxation is a rare complication after AGC knees. It is believed that the primary factor causing progressive subluxation is tightness of the PCL. The PCL should be recessed if PCL tightness is seen at surgery.

The consequences of lateral release in total knee replacement: a review of over 1000 knees with follow up between 5 and 11 years.

BACKGROUND: The relationship between lateral release in total knee arthroplasty and subsequent patello-femoral problems is contentious. Variable rates of instability, patella fracture and other complications have been demonstrated after lateral release. Significant measures have been taken by some surgeons to avoid a lateral release. We wished to determine whether lateral release was detrimental or beneficial in terms of mid- to long- term patellofemoral problems. METHODS: We examined 1071 total knee arthroplasties with a follow-up of 5 to 11 years to determine the longer-term consequences of lateral release. Lateral release was performed as clinically indicated after a 'no thumbs' assessment in 51% of cases. The knees requiring a lateral release had lower pre-operative Hospital for Special Surgery (HSS) scores and demonstrated a greater improvement in post-operative HSS scores. RESULTS: The difference in HSS scores, between the groups, was significantly less post-operatively than prior to surgery. Overall, we had a high incidence of lateral release (51%), but low fracture rate (1.2%), and very low instability rate (0.6%). Only three surgeries were required for patello-femoral problems. CONCLUSION: This study suggests that any negative consequences of lateral release are minimal and we recommend lateral release continue to be performed as clinically indicated.

The effect of femoral component rotation and asymmetry in total knee replacements.

Between April 1999 and February 2000, femoral component rotation and asymmetry (universal versus anatomic) were studied in a prospective randomized control trial in 101 consecutive patients undergoing total knee replacement. Patients were randomly assigned to four groups. The same surgical technique was used in all patients except for femoral component symmetry and rotational alignment. Universal femoral components provide a cheaper and equally reliable solution compared to anatomic compo nents. External rotation of the femoral component or using an anatomic femoral component did not statistically reduce the need for lateral release or improve patellar tracking.

Ten to fourteen year survival and functional analysis of the AGC total knee replacement system.

A study of 562 Anatomic Graduated Component (AGC) total knee arthroplasties that were performed in 402 patients between November 1986 and September 1990 is reported. All patients had implantation with a cemented posterior cruciate-retaining design, with resurfacing of the patella using all polyethylene patella components. Mean age at surgery was 71 years (range 41-92 years). Patients were followed for a minimum of 10 years (range 10-14 years). Nine knees were lost to follow-up (1.4%). The mean Knee Society Score for pain and function were analyzed by Charnley categories: Category A -- 97 (pain) and 89 (function); Category B -- 91 (pain) and 84 (function); and Category C -- 89 (pain) and 62 (function). The survival analysis at 14 years was 97% with revision for any reason as the endpoint and the authors continue to utilize this implant system.

Results of simultaneous bilateral total knee replacement: a study of 1208 knees in 604 patients.

Bilateral symptomatic knee arthritis is a common clinical problem. There are conflicting opinions as to the advisability of simultaneous sequential bilateral total knee replacement. Complication rates of primary unilateral knee replacement are well documented and there are several small series that compare the two techniques. The objective of this study was to identify the complication rate of simultaneous sequential bilateral total knee replacement in a large patient population. Over a 13-year period, 604 primary bilateral sequential simultaneous total knee replacements (1208 knees) were performed. Office notes and hospital charts were retrospectively reviewed to obtain age, sex, diagnosis, knee alignment, associated comorbidities, operative protocol, transfusions, and complications. The study results showed 5.1% local and 15.3% systemic complications and 0.7% mortality rate (none in the past 9 years). With appropriate patient selection and operative technique, patients who present with bilateral symptomatic knee arthritis can enjoy the benefits of simultaneous sequential bilateral total knee replacement without increasing their risks of complications.