Merrill A. Ritter

Objectives: The purpose of this study was to examine the effect of posterior cruciate ligament (PCL) retention, PCL recession, and PCL excision during cruciate-retaining total knee replacement.Methods: A total of 3018 anatomic graduated component total knee replacements were examined; 1846 of these retained the PCL, 455 PCLs were partially recessed, and in 717 the PCL was completely excised from the back of the tibia.Results: Clinical scores between PCL groups favored excision for flexion (p < 0.0001), and recession and retention for stairs (p < 0.0001). There was a mild difference in long-term all-cause aseptic survivorship between PCL-retained (96.4% at 15 years) combined with PCL-recessed groups (96.6% at 15 years) when compared with the PCL-excised group (95.0% at 15 years) (p = 0.0411, Wilcoxon; p = 0.0042, log-rank), as well as tibial or femoral loosening, which reported prosthesis survival of 97.8% at 15 years for PCL-retained knees, 98.2% for recessed knees, and 96.4% for excised knees (p = 0.0934, Wilcoxon; p = 0.0202, log-rank).Conclusions: Despite some trade-off in clinical performance, if the PCL is detached at the time of operation, conversion to a posterior-stabilised prosthesis may not be necessarily required as long as stability in the anteroposterior and coronal planes is achieved.

Mum of two years of follow-up. Each knee was classified on the basis of postoperative alignment (overall tibiofemoral alignment and alignment of the tibial and the femoral component in the coronal plane). Failures (defined as revision for any reason other than infection) were analyzed with use of Cox regression; patient covariates included overall alignment, component alignments, and preoperative BMI. Results: Failure was most likely to occur if the orientation of the tibial component was <90° relative to the tibial axis and the orientation of the femoral component was ≥8° of valgus (failure rate, 8.7%; p < 0.0001). In contrast, failure was least likely to occur if both the tibial and the femoral component were in a neutral orientation (≥90° and <8° of valgus, respectively) (failure rate, 0.2% [nine of 4633]; p < 0.0001). “Correction” of varus or valgus malalignment of the first implanted component by placement of the second component to attain neutral tibiofemoral alignment was associated with a failure rate of 3.2% (p = 0.4922) for varus tibial malalignment and 7.8% (p = 0.0082) for valgus femoral malalignment. A higher BMI was associated with an increased failure rate. Compared with patients with a BMI of 23 to 26 kg/m2, the failure rate in patients with a BMI of ≥41 kg/m2 increased from 0.7% to 2.6% (p = 0.0046) in well-aligned knees, from 1.6% to 2.9% (p = 0.0180) in varus knees, and from 1.0% to 7.1% (p = 0.0260) in valgus knees. Conclusions: Attaining neutrality in all three alignments is important in maximizing total knee implant survival. Substantial “correction” of the alignment of one component in order to compensate for malalignment of the other component and thus produce a neutrally aligned total knee replacement can increase the risk of failure (p = 0.0082). The use of conventional guides to align a total knee replacement provides acceptable alignment; however, the surgeon should be aware that the patient's size, as determined by the BMI, is also a major factor in total knee replacement failure. Level of Evidence: Prognostic Level II. See Instructions to Authors for a complete description of levels of evidence....

Ior cruciate-retaining prosthesis....

Unlike the knee, range of motion has been of questionable value in evaluating clinical outcome after THA. We retrospectively analyzed the ranges of motion (flexion, abduction, adduction, external rotation, internal rotation, and flexion contracture) of 1383 patients (1517 hips) having primary THA. We recorded Harris hip score components for walking distance, stair climbing, socks and shoes, sitting, pain, presence of limp, and use of support devices. Postoperative hip motion was defined as high (115° of flexion, 25° of abduction, 20° of external rotation, and less than 20° of flexion contracture), average (90°-114° of flexion, 16°-24° of abduction, or 11°-19° of external rotation, and less than 20° of flexion contracture), or low (less than 90° of flexion, 15° or less of abduction, 10° or less of external rotation, or 20° or more of flexion contracture) motion. We correlated this with high, average, or poor postoperative Harris hip scores. Hip motion was found to be correlated with postoperative hip function and may be more useful than previously thought in evaluating hip outcome. Level of Evidence: Level IV, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Rpose of the present study was to compare the infection rates following joint replacement procedures performed by one orthopaedic surgeon with and without the use of ultraviolet lighting....

Background: Ultraviolet lighting is an alternative to laminar airflow in the operating room that may be as effective for lowering the number of environmental bacteria and possibly lowering infection rates by killing the bacteria rather than simply reducing the number at the operative site. The purpose of the present study was to compare the infection rates following joint replacement procedures performed by one orthopaedic surgeon with and without the use of ultraviolet lighting. Methods: From July 1986 to July 2005, one surgeon performed 5980 total joint replacements at one facility. In September 1991, ultraviolet lighting was installed in the operating rooms. All procedures that were performed before the installation of the ultraviolet lighting utilized horizontal laminar airflow, whereas all procedures that were performed after that date utilized ultraviolet lighting without laminar airflow. Factors associated with the rate of infection were analyzed. Results: Over a nineteen-year period, forty-seven infections occurred following 5980 joint replacements. The infection rate without ultraviolet lighting (and with laminar airflow) was 1.77%, and the infection rate with ultraviolet lighting was 0.57% (p < 0.0001). The odds of infection were 3.1 times greater for procedures performed without ultraviolet lighting (and with laminar airflow) as compared with those performed with only ultraviolet lighting (p < 0.0001). The infection rate associated with total hip replacement decreased from 1.03% to 0.72% (p = 0.5407), and the infection rate associated with total knee replacement decreased from 2.20% to 0.50% (p < 0.0001). Revision surgery, previous infection, age, total body mass index, use of cement, disease, and diagnosis were not associated with an elevated infection rate. Conclusion: When appropriate safety precautions are taken, ultraviolet lighting appears to be an effective way to lower the risk of infection in the operating room during total joint replacement surgery. Level of Evidence: Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.

Background: Following total knee arthroplasty, some patients who fail to achieve >90° of flexion in the early perioperative period may be considered candidates for manipulation of the knee under anesthesia. The purpose of this study was to assess the outcomes of manipulation following total knee arthroplasty. Methods: One hundred and thirteen knees in ninety patients underwent manipulation for postoperative flexion of ≤90° at a mean of ten weeks after surgery. Flexion was measured with a goniometer prior to total knee arthroplasty, at the conclusion of the operative procedure, before manipulation, immediately after manipulation, at six months, and at one, three, and five years postoperatively. Results: Eighty-one (90%) of the ninety patients achieved improvement of ultimate knee flexion following manipulation. The average flexion was 102° prior to total knee arthroplasty, 111° following skin closure, and 70° before manipulation. The average improvement in flexion from the measurement made before manipulation to that recorded at the five-year follow-up was 35° (p < 0.0001, paired t test). There was no significant difference in the mean improvement in flexion when patients who had manipulation within twelve weeks postoperatively were compared with those who had manipulation more than twelve weeks postoperatively. Patients who eventually underwent manipulation had significantly lower preoperative Knee Society pain scores (more pain) than those who had not had manipulation (p = 0.0027). Conclusions: Manipulation generally increases ultimate flexion following total knee arthroplasty. Patients with severe preoperative pain are more likely to require manipulation. Level of Evidence: Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.

Background: Following total knee arthroplasty, some patients who fail to achieve >90° of flexion in the early perioperative period may be considered candidates for manipulation of the knee under anesthesia. The purpose of this study was to assess the outcomes of manipulation following total knee arthroplasty. Methods: One hundred and thirteen knees in ninety patients underwent manipulation for postoperative flexion of ≤90° at a mean of ten weeks after surgery. Flexion was measured with a goniometer prior to total knee arthroplasty, at the conclusion of the operative procedure, before manipulation, immediately after manipulation, at six months, and at one, three, and five years postoperatively. Results: Eighty-one (90%) of the ninety patients achieved improvement of ultimate knee flexion following manipulation. The average flexion was 102° prior to total knee arthroplasty, 111° following skin closure, and 70° before manipulation. The average improvement in flexion from the measurement made before manipulation to that recorded at the five-year follow-up was 35° (p < 0.0001, paired t test). There was no significant difference in the mean improvement in flexion when patients who had manipulation within twelve weeks postoperatively were compared with those who had manipulation more than twelve weeks postoperatively. Patients who eventually underwent manipulation had significantly lower preoperative Knee Society pain scores (more pain) than those who had not had manipulation (p = 0.0027). Conclusions: Manipulation generally increases ultimate flexion following total knee arthroplasty. Patients with severe preoperative pain are more likely to require manipulation. Level of Evidence: Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.

In the past decade, there has been a renewed interest in hip resurfacing due to recent design improvements. It is unclear whether the recent improvements have accounted for all of the previous failure mechanisms. We determined the long-term performance of hip resurfacing, while paying special attention to the mechanisms of failure. We retrospectively reviewed 62 patients (65 hips) who had Indiana conservative hip prostheses implanted between 1977 and 1981. Forty-one of 62 joints had failed, representing a failure rate of 66%. The time to failure averaged 9.7 years with a range of 6 months to 21.5 years. There were 23 femoral failures (37%). Eleven were caused by femoral fracture, and 12 were caused by femoral loosening. All late femoral failures (greater than 10 years postoperatively) showed narrowing of the femoral neck secondary to stress shielding. There were 18 acetabular failures (29%) with 10 failing secondary to polyethylene wear and eight failing secondary to acetabular loosening. Failure of the Indiana conservative hip prosthesis continues over time related to femoral and acetabular failure mechanisms. These data should be considered in the context of growing enthusiasm for resurfacing with new bearing surfaces and cementless fixation. Level of Evidence: Level IV, case series. See the Guidelines for Authors for a complete description of levels of evidence.