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Despite high survivorship for total knee arthroplasty, many reports have described low patient-satisfaction rates. Standard parapatellar approaches have been linked with decreased quadriceps muscle strength, which may in turn lead to prolonged rehabilitation and altered kinematics. Although technically demanding, minimally invasive techniques offer the potential for shorter recovery times and improved strength. Our purpose was to compare perioperative factors, the clinical and radiographic outcomes, complications, and survivorship of several minimally invasive approaches to each other and to the conventional medial parapatellar approach. A total of 23 level I or II studies were reviewed. There were no statistically significant differences in perioperative factors, clinical or radiographic outcomes, survivorship, or complication rates between patients the various minimally invasive approaches to a standard approach. The only significant difference observed was in recovery of quadriceps muscle function (shorter in patients who had a minimally invasive approach). The minimally invasive lateral approach had more complications than the other minimally invasive approaches. The mini-midvastus approach had the best clinical outcomes at 1 and 3 months when compared with other minimally invasive approaches and standard approaches. The mini-subvastus approach had the lowest rate of complications, overall. Further multicenter randomized trials are needed to determine the minimally invasive approach that best improves outcomes while minimizing complications., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Cruciate-retaining total knee arthroplasty has had high success rates but does not always have optimal functional outcomes. The purpose of this study was to compare 2 polyethylene inserts of varying constraint that were used in a new cruciate-retaining total knee arthroplasty design to determine whether differences were found in clinical or functional outcomes. The use of the newer cruciate-retaining total knee arthroplasty design showed comparable results with both polyethylene inserts at short-term follow-up. The cruciate-retaining design had a greater than 99% survivorship, although further study is needed to make assessments regarding long-term functional results and outcomes., (Copyright 2013, SLACK Incorporated.)

Background: TKA with retention of the anterior cruciate ligament (ACL) may improve kinematics and function. However, conflicting reports exist concerning the prevalence of intact ACLs at the time of TKA., Questions/purposes: Therefore, we asked: (1) what was the ACL status at TKA; (2) what was the sensitivity and specificity of the Lachman test; (3) did MRI ACL integrity correlate with intraoperative observation; (4) did MRI tibial wear patterns correlate with ACL integrity; and (5) did ACL status depend on age or sex?, Methods: We evaluated 200 patients for ACL integrity at the time of TKA. All patients underwent a Lachman test under anesthesia. Intraoperatively, the ACL was characterized as intact, frayed, disrupted, or absent. In 100 patients, MRIs were performed, from which the ACL was graded as intact, indeterminate, or disrupted, and the AP location of tibial wear was categorized., Results: The ACL was intact in 155 patients (78%). The Lachman test alone had poor diagnostic ability. The MRI predicted a tear, but we observed two ACLs with indeterminate status that were disrupted. All knees with anterior wear on the medial tibial condyle had an intact ACL (n = 45), and all knees with posterior wear on the medial tibial condyle had a disrupted ACL (n = 8)., Conclusions: Although the Lachman test alone had poor sensitivity, when combined with MRI they together provide a sensitivity of 93.3% and specificity of 99%, which we believe makes these reasonable tests for assessing ACL status in the arthritic knee.

Advances in surgical technique and implant design have increased the treatment options available to joint reconstruction surgeons. New technologies for component alignment such as custom cutting blocks and disposable cutting blocks hold the potential for more anatomic component positioning and less instrument turnover which may decrease infection rates. Improved component alignment may also be obtained with the use of computer-assisted surgery. Utilization of bone-sparing designs such as patellofemoral, unicompartmental, and bicompartmental knee arthroplasty allow for the surgeon to customize treatment based on patient symptoms by addressing each compartment individually. Gender-specific designs may be useful in the setting of populations which deviate from standard dimensions that are available in traditional unisex designs. New higher-conforming bearing designs such as rotating platform bearings allow for more natural knee kinematics, while also limiting polyethylene wear by decreasing contact stress. Newer interfaces for cementless fixation utilizing porous coated surfaces allows for biologic component fixation which has the potential to increase interface durability and implant survivorship. These new materials, designs, and techniques are challenging the traditional "gold standard" cemented total knee arthroplasty and have the potential for developing a more durable and naturally feeling prosthetic knee. Further study is required to identify which patients are most appropriate for each new technology.

This prospective randomized study compared the clinical and radiographic outcomes of unicompartmental knee arthroplasty versus total knee arthroplasty. The group consisted of 34 patients (19 males and 15 females), who had a mean age of 73 years (range, 49 to 86 years), and who fit the criteria for bilateral unicompartmental knee arthroplasty. Each patient received a unicompartmental prosthesis in one knee and a total knee arthroplasty in the other during a single anesthetic session. At a mean follow-up of 5 years (range, 24 to 89 months), the Knee Society pain and function scores were similar for both groups. There were no radiographic failures. Survivorship of the unicompartmental group was 85% compared with 100% in the total knee group (p = 0.05). All of the prostheses that failed had an all-polyethylene tibial component. These results suggest that unicompartmental knee arthroplasty may not offer similar survivorship when compared with total knee arthroplasty.

The first 103 consecutive minimally invasive total knee arthroplasties performed by a single surgeon were assessed to determine the clinical and radiographic outcomes at a mean of 9-year follow-up (range, 8 to 10 years). Patients who died before final follow-up were 10 (13 knees), leaving 90 knees in 69 patients for final review. Outcome was evaluated using Knee Society pain and functional scores. Survival with revision as an end point was 97.1%. Knee Society scores and range of motion improved significantly to a mean of 96 and 92 points and a mean of 115 degrees, respectively. There were five patients who required surgical intervention for unexplained pain with findings of retained cement and adhesions. Radiographic analysis did not reveal any progressive radiolucencies. These results suggest that excellent long-term outcomes can be achieved with minimally invasive total knee arthroplasty.

Background: Gender-specific differences in knee and hip anatomy have been well documented. Although it has been accepted these differences exist, there is controversy regarding if and how these differences should be addressed with gender-specific implant designs., Questions/purposes: (1) What are the anatomic and morphologic differences, if any, in the knee and hip between men and women? (2) Do gender-specific TKA designs provide better clinical functioning, survivorship, and improved fit in women? (3) How have anatomic differences in the hip been addressed, if at all, by THA?, Methods: We conducted a systematic review of the MEDLINE database to identify all articles reviewing basic science and clinical outcomes of gender-specific total knee and total hip implants. From these, we reviewed 253 studies., Results: The anatomic studies elucidated multiple differences in the anatomy of knees and hips between men and women. All reviewed studies report similar clinical function and satisfaction scores between men and women for gender-specific TKA and no improvement in these scores when comparing gender-specific TKA to unisex TKA. Current modularity in THA appears to accommodate any anatomic differences in the hip., Conclusions: Based on the available literature, there is no difference in the outcome of patients with a gender-specific knee arthroplasty versus a unisex arthroplasty. It does not appear gender-specific THAs would provide any benefit over current systems.