Karen Smith

Delamination cysts: a predictor of acetabular cartilage delamination in hips with a labral tear.

The treatment and prognosis of labral tears of the hip depend primarily on whether there is concomitant injury of the adjacent acetabular articular cartilage. We asked whether a delamination cyst on the preoperative plain radiographs correlated with delamination of the acetabular articular cartilage at the time of hip arthroscopy. We reviewed the preoperative radiographs of 125 consecutive hips that had a labral tear at hip arthroscopy for the presence of a delamination cyst. A delamination cyst was defined as an acetabular subchondral cyst either directly adjacent to a lateral acetabular cyst or in relation to a subchondral crack in the anterosuperior portion of the acetabulum. All patients with acetabular cartilage delamination at arthroscopy were identified. There were 16 patients with delamination cysts on radiographs and 15 patients with cartilage delamination at arthroscopy. A delamination cyst on the preoperative anteroposterior and/or frog lateral radiographs of the hip accurately predicted acetabular cartilage delamination, especially in hips with labral tears not caused by a major trauma. A delamination cyst is a previously unrecognized and novel radiographic sign that can preoperatively identify acetabular cartilage delamination in patients with labral tears, thereby facilitating the selection of the appropriate surgery and determining prognosis.Level of Evidence: Level II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Nucleotide clusters in deoxyribonucleic acids: XIV. Pyrimidine oligonucleotides of the left and right halves and λdv region of bacteriophage lambda DNA

Abstract The distribution of pyrimidine oligonucleotide tracts from purified right and left halves of bacteriophage λ DNA and the DNA of the episome λ dv -1 have been determined. The oligonucleotides C 8 T, CT 9 , C 2 T 9 , C 3 T 8 , C 7 T 4 , C 2 T 10 , C 3 T 9 , C 7 T 5 , C 4 T 9 , C 6 T 7 , C 2 T 12 , C 10 T 4 , and C 3 T 13(or 14) were found to be specific for the right half of the λ DNA while C 7 T, C 4 T 8 , C 5 T 7 , C 8 T 5 , C 4 T 10 , and C 8 T 7 were specific for the left half. The λ dv region of the λ DNA molecule was found to contain four of the longest pyrimidine oligonucleotides occurring uniquely in λ DNA. These were identified as having the base compositions C 6 T 7 , C 2 T 12 , C 10 T 4 , and C 3 T 13(or 14) . Oligonucleotides C 7 T, C 7 T 2 , C 8 T, C 7 T 3 , C 5 T 7 , C 6 T 7 , C 2 T 12 , C 4 T 10 , C 10 T 4 , C 8 T 7 , and C 3 T 13(or 14) observed in this study have not been previously observed to occur in λ DNA. Oligonucleotide base compositions and tract numbers of the longest oligonucleotides were confirmed by nucleotide sequence analysis of selected oligonucleotides occurring in the left and right halves and all oligonucleotides occurring uniquely in the λ dv plasmid. Many of the uniquely occurring pyrimidine oligonucleotides were found to contain symmetrical sequences of at least 10 nucleotides. The longest such sequence was TTTTCTTTTTCTTT(T), occurring in oligonucleotide C 3 T 13(or 14) .

Surface Replacement of the Hip Can Result in Decreased Acetabular Bone Stock

BackgroundThe recent interest in hip resurfacing arthroplasty is motivated by its potential advantages over THA. One advantage of hip resurfacing arthroplasty is that it conserves bone on the femoral side; however, it is unclear whether it does so on the acetabular side.Questions/purposesWe determined whether the amount of acetabular reaming and acetabular bone removal required for hip resurfacing arthroplasty is equal to, less than, or greater than that for THA.Patients and MethodsWe prospectively evaluated the femoral neck size of 180 hips at the time of primary THA in an identical manner to when carrying out a hip resurfacing arthroplasty. Based on the femoral neck measurement, we determined the minimum cup size that would be used and reamer size required if the hip was undergoing a resurfacing. We compared this to the reamer size actually required to prepare the acetabulum for the THA cup. We calculated the difference between the predicted reaming size for resurfacing and the actual reaming size to determine the effect of resurfacing on acetabular bone stock.ResultsOverall, 71%, 57%, and 41% of THAs would have had extra acetabular bone removed to implant a hip resurfacing arthroplasty cup with a line-to-line (0-mm), 1-mm, or 2-mm press fit, respectively.ConclusionsWhen compared to THA, hip resurfacing arthroplasty commonly results in additional acetabular bone resection.

Primary Total Hip Arthroplasty: Equivalent Outcomes in Low and High Functioning Patients.

Objective:Previous studies suggest that patients with poorer physical function prior to undergoing total hip arthroplasty (THA) have a lower postoperative functional outcome. We sought to determine if the preoperative level of function was predictive of the outcome in patients undergoing THA using modern perioperative protocols and surgical techniques. Methods:A prospective cohort study design evaluated the preoperative and 2-year postoperative health-related quality of life (HRQoL) scores of 200 patients who underwent THA. The cohort was divided into two groups according to the median preoperative Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function scores. Results:Both high and low function groups had significant improvements in the HRQoL scores (P < 0.001). However, this improvement was substantially greater in the low function group, resulting in no difference in the HRQoL outcomes of the two groups at final follow-up. Conclusion:This study contradicts the previously held belief that patients with worse function before THA do not do as well as those with less preoperative disability. Level of Evidence:Level II.

Changing Surgeons Improves Outcome of Subsequent Primary Total Joint Arthroplasty in Previously Dissatisfied Patients

We assessed whether patients who were dissatisfied with their previous primary hip (THA) or knee (TKA) arthroplasty, done by another surgeon, would have continued dissatisfaction or would have significant improvements in outcome scores following their subsequent primary THA or TKA. The majority of reasons provided for switching surgeons and/or institutions related to dissatisfaction with some aspect of their surgical experience specifically involving the surgeon-patient interaction itself. All 12 THA and TKA patients noted that their subsequent arthroplasty had decreased their pain, improved their function and that they were satisfied with their result. All patients had a statistically significant improvement in their Harris Hip Score or Knee Society Score, WOMAC and SF-36 questionnaires. This study demonstrates that previous dissatisfaction with a THA or THA does not predispose to a suboptimal outcome following subsequent primary hip or knee arthroplasty.

Washing the Femoral Canal Results in More Predictable Seating of a Short, Tapered Femoral Stem

BACKGROUND It is critical that a femoral rasp be effective in preparing the proximal femur to accept the size and the geometry of the femoral implant at the time of total hip arthroplasty. Short, tapered femoral stems may be at greater risk because they require the preparation of a short femoral region without any reaming. We undertook a study to determine the effect on implant seating in femora that were prepared by rasping alone with those that were rasped and the canal was washed with saline at the time of cementless THA with a short, tapered femoral implant. METHODS We retrospectively analyzed the preoperative, intraoperative, and radiographic data on 170 consecutive patients undergoing a primary THA using a short, taper, uncemented metaphyseal-filling stem. The femur was prepared using a rasp-only technique. In the initial 99 patients, the canal was rasped, but not washed (group 1). In the subsequent 71 patients, the canal was rasped and before implant insertion the canal was washed with 100 cc of normal saline to remove all loose cancellous bone (group 2). Intraoperatively, the distance between the calcar cut and the rasp and subsequently, the calcar cut and the implant was measured. We defined a difference of more than 2 mm between the seating of the rasp and the final implant as a clinically significant mismatch. RESULTS Overall, a clinically significant mismatch occurred in 50% (49/99) of cases in group 1 and 15% (11/71) in group 2. Multivariate logistic regression analysis corrected for preoperative, intraoperative, and radiographic measurements showed that washing significantly decreased the mismatch between the rasp and the implant (odds ratio, 5.32; confidence interval, 2.10-13.73; P < .001). CONCLUSION Although the present rasp design is sufficient to create the geometric space for this short, metaphyseal stem, it does not adequately remove the bone debris to ensure reproducible seating of the implant. Washing the femoral metaphysis with saline to remove bone debris, after rasping and before inserting the final implant, significantly decreased the mismatch between seating of the final rasp and the implant in this cementless short, metaphyseal-filling, taper design stem. Level of Evidence III.

Changing Patient Expectations Decreases Length of Stay in an Enhanced Recovery Program for THA

Background The implementation of care pathways in hip arthroplasty programs has been shown to result in a decreased length of stay (LOS), but often multiple elements of a care pathway are implemented at the same time. As a result, it is difficult to understand the impact each of the individual modifications has made to the patient’s prepathway care. In particular, it is unknown what the role of patient expectations pertaining to anticipated LOS alone is on the LOS after primary THA. Questions/purposes (1) Does changing the patient’s expectations regarding his or her anticipated LOS, without intentionally changing the rest of the care pathway, result in a change in the patient’s LOS after primary THA? (2) Is the resultant LOS associated with the patient’s age, gender, or day of the week the surgery was performed? Methods We retrospectively compared the LOS in 100 consecutive patients undergoing THA immediately after the implementation of a 4-day care pathway (4-day Group) with 100 consecutive patients, 3 months later, who were also in the same pathway but were told by their surgeon preoperatively and in the hospital to expect a LOS of 2 days (2-day Group). Aside from reeducation by the surgeon, there was no difference in the surgery or intentional changes to the intraoperative or postoperative management of the two groups. Only the patient and the surgeon were made aware of the accelerated discharge plan. We compared the LOS between the two groups and the number of patients who met their discharge goal. As well, the ability to meet the discharge goal for each group was further determined based on age, gender, and day of the week the surgery was performed. Results Overall, patients in the 2-day Group had a shorter LOS than those in the 4-day Group (2.9 ± 0.88 days versus 3.9 ± 1.71 days; mean difference 1 day; 95% confidence interval [CI], 0.60-1.36; p = 0.001). In the 2-day Group, the LOS was 2 days in 32% compared with 8% in the 4-day Group (odds ratio, 4.0; 95% CI, 1.76-9.11; p < 0.001). Men in the 4-day Group had a shorter LOS than women (3.4 ± 1.22 days versus 4.2 ± 1.89 days; mean difference 0.8 days; 95% CI, 0.17-1.78; p = 0.019), but there was no difference in LOS by gender in the 2-day Group (2.8 ± 0.81 days versus 3.1 ± 0.93 days; mean difference 0.3 days; 95% CI, -0.14 to 0.61; p = 0.219). For all patients > 40 years and < 90 years of age, a greater percentage of patients in the 2-day Group went home by postoperative day 2 than those in the 4-day Group (32% compared with 7%; odds ratio, 4.6; p < 0.001). In both groups, there was no difference in the LOS if the surgery was on Friday compared with an earlier day of the week (4-day Group: 3.4 ± 0.67 days versus 4.0 ± 1.80 days; p = 0.477 and 2-day Group: 2.8 ± 0.62 days versus 3.0 ± 0.93 days; p = 0.547). Conclusions We found that a surgeon who sets a clear expectation in terms of LOS could achieve a reduction in this parameter. Although it is impossible to be certain in the context of a retrospective study whether other caregivers adjusted the pathway in response to the surgeon’s preferences, and we suspect this probably did occur, this still points to an opportunity on the topic of expectations setting that future studies should explore. This study highlights the influence patient education and expectations has on the effectiveness of care pathways in THA as well as the importance of continuous reinforcement of discharge planning both preoperatively and in the hospital. Level of Evidence: Level III, therapeutic study.