Outcomes of Short and Long Tibial Stems for Primary Total Knee Arthroplasty in a Population of Obese Patients at Two-Year Follow-Up: A Clinical and Biomechanical Study.

BACKGROUND: Obesity can be a source of higher failure rates and inferior clinical outcomes after total knee arthroplasty (TKA). The aim of this study was to compare outcomes, failure rates, and stress distributions of TKA in obese patients using a short, long, or no tibial stem. METHODS: A matching process based on the type of stem used and the age allowed included 180 patients who had a body mass index (BMI) > 30 and underwent a TKA between January 2010 and December 2019, with a minimum follow-up of 2 years. They were classified as moderately obese (MO: 30 < BMI < 35, N = 90) and severely obese (SO: BMI > 35, N = 90). For each, 3 subgroups were defined: thirty patients received a 30 mm short stem (SS), thirty received a 100 mm long stem (LS), and thirty received no stem (NS). Patients were assessed preoperatively and postoperatively using the Knee Society Score (KSS). A finite element model was developed to evaluate the biomechanical effects of the tibial stem on stress distribution in the subchondral bone based on BMI. RESULTS: The SS patients had significantly higher postoperative KSS knee score [MO: 88.9 (SS) versus 79 (LS) versus 80.6 (NS); SO: 84.5 versus 72.4 versus 78.2] (P < .0001) and function score [MO: 90.4 (SS) versus 78.4 (LS) versus 68.5 (NS); SO: 85.5 versus 73 versus 61.8] (P < .0001) compared to LS and NS patients. The biomechanical study demonstrated a BMI-dependent increase in stress in the subchondral bone in contact with the tibial components. These stresses were mainly distributed at the tibial cut for NS and along the stem for SS and LS. CONCLUSIONS: A short, cemented tibial stem offers better functional outcomes without increasing failure rates compared to a longer stem during primary TKA in a population of obese patients at two-year follow-up. A short tibial stem does not lead to increased stress compared to an LS, at least for certain BMI categories.

Better satisfaction of patients operated on anterior cruciate ligament reconstruction in outpatient setting. A prospective comparative monocentric study of 60 cases.

INTRODUCTION: The purpose of this study was to compare satisfaction, clinical scores, and complications of patients operated on anterior cruciate ligament reconstruction (ACLR) in outpatient setting compared to patients operated in the conventional hospitalization. PATIENTS AND METHODS: This prospective non-randomized study compared 30 patients (mean age 31 ± 9 years) operated on outpatient setting for an isolated ACLR matched 1:1 according to age, gender, body mass index, delay to surgery, and preoperative clinical score (IKDC) to 30 patients operated for an ACLR in our conventional hospitalization department during the same period. All the patients were operated on by the same surgeon. The same technique of anterior cruciate ligament reconstruction with using four bundles semitendinosus and cage fixation was used. The same anaesthesiologic protocol and perioperative cares were used in all patients. Patients' satisfaction was assed using five questions about the course of surgery and hospitalization and a four-level satisfaction questionnaire (excellent, good, fair, and poor). Clinical scores (IKDC and KOOS) were compared preoperatively and at 1 year. Readmission within 30 day and complications at 1 year were compared in both groups. RESULTS: Satisfaction was significantly better in the group of day-case surgery and more patients of the group day-case surgery recommended this modality of treatment (29 against 24; p = 0.04). The IKDC score improved in the two groups (day-case group from 64 ± 17 to 86 ± 7; p < 0.001; conventional hospitalization from 60 ± 21 to 85 ± 10; p < 0.001), but no significant difference between two groups was found at 1 year (p = 0.86). No readmission was necessary in the two groups, but two revisions were needed in the group of the conventional hospitalization. CONCLUSIONS: Results of our study showed that patients operated on day-case surgery for an isolated ACLR presented a higher rate of satisfaction compared to patients operated in the conventional hospitalization with comparable clinical results at 1 year. LEVEL OF EVIDENCE: Level III, comparative study.

Global Forum: An International Perspective on Outpatient Surgical Procedures for Adult Hip and Knee Reconstruction.

Outpatient surgical procedures for adult hip and knee reconstruction are gaining interest on a worldwide basis and have been progressively increasing over the last few years. Preoperative screening needs to concentrate on both the patient's comorbidities and home environment to provide a proper alignment of expectations of the surgeon, the patient, and the patient's family. Preoperative multidisciplinary patient information covering all aspects of the upcoming treatment course is a mandatory step, focusing on pain management and early mobilization. Perioperative pain management includes both multimodal and preventive analgesia. Preemptive medications, minimization of narcotics, and combination of general and regional anesthesia are the techniques required in joint arthroplasty performed as an outpatient surgical procedure. A multimodal blood loss management program should be used with preoperative identification of anemia and attention directed toward minimizing blood loss, considering the use of tranexamic acid during the surgical procedure. Postoperative care extends from the initial recovery from anesthesia to the physical therapist's evaluation of the patient's ambulatory status. After the patient has met the criteria for discharge and has been discharged on the same day of the surgical procedure, a nurse should call the patient later at home to check on wound status, pain control, and muscle weakness, which will be further addressed by physiotherapy and education. Implementing outpatient arthroplasty requires monitoring safety, patient satisfaction, and economic impact.

No Benefit After THA Performed With Computer-assisted Cup Placement: 10-year Results of a Randomized Controlled Study.

BACKGROUND: Computer-assisted surgery (CAS) for cup placement has been developed to improve the functional results and to reduce the dislocation rate and wear after total hip arthroplasty (THA). Previously published studies demonstrated radiographic benefits of CAS in terms of implant position, but whether these improvements result in clinically important differences that patients might perceive remains largely unknown. QUESTIONS/PURPOSES: We hypothesized that THA performed with CAS would improve 10-year patient-reported outcomes measured by validated scoring tools, reduce acetabular polyethylene wear as measured using a validated radiological method, and increase survivorship. METHODS: Sixty patients operated on for a THA between April 2004 and April 2005 were randomized into two groups using either the CAS technique or a conventional technique for cup placement. All patient candidates for a THA with the diagnosis of primary arthritis or avascular necrosis were eligible for the CAS procedure and randomly assigned to the CAS group by the Hospital Informatics Department with use of a systematic sampling method. The patients assigned to the freehand cup placement group were matched for sex, age within 5 years, pathological condition, operatively treated side, and body mass index within 3 points. All patients were operated on through an anterolateral approach (patient in the supine position) using cementless implants. In the CAS group, a specific surgical procedure using an imageless cup positioning computer-based navigation system was performed. There were 16 men and 14 women in each group; mean age was 62 years (range, 24-80 years), and mean body mass index was 25 ± 3 kg/m(2). No patient was lost to followup at 10 years, but five patients have died (two in the CAS group and three in the control group). At the 10-year followup, an independent observer blinded to the type of technique performed patients' evaluation. Cup positioning was evaluated postoperatively using a CT scan in the two groups with results previously published. At 10 years, we assessed subjective functional outcome and quality of life using validated questionnaires (SF-12, Harris hip score [HHS], Hip injury and Osteoarthritis Outcome Score). Wear rate was then evaluated on standardized radiographs using a previously validated semiautomated computer analogic measurement method (dual circle method). Complications and survivorship were compared between groups. With our available sample size, this study had 80% power to detect a difference of 4 points out of 100 on the HHS at the p < 0.05 level. RESULTS: With the numbers available, we found we found no differences between groups regarding HSS at last followup 95.3 ± 5.9 points (CAS group) versus 96.2 ± 4.5 points, a mean difference of 0.9 points (95% confidence interval [CI], -4.3 to 4.6; p = 0.6). There was no difference between the groups in terms of the mean (± SD) acetabular linear wear at 10 years. The mean wear was 0.71 ± 0.6 mm in the CAS group versus 0.77 ± 0.52 mm in the control group, a mean difference of 0.06 mm (95% CI, -0.1 to 0.2; p = 0.54). With the numbers available, there was no difference between the CAS group and the conventional THA groups in terms of survivorship free from aseptic loosening (100%; 95% CI, 100%-95%, versus 100%; 95% CI, 100%-94%; p = 0.3). CONCLUSIONS: Our observations suggest that CAS used for cup placement does not confer any substantial advantage in function, wear rate, or survivorship at 10 years after THA. Because CAS is associated with added costs and surgical time, future studies need to identify what clinically relevant advantages it offers, if any, to justify its continued use in THA. LEVEL OF EVIDENCE: Level II, therapeutic study.

Are Revisions of Unicompartmental Knee Arthroplasties More Like a Primary or Revision TKA?

If revision is required, most unicompartmental arhroplasties (UKAs) are converted to total knee arthroplasties (TKAs) and conflicting results regarding surgical complexity and outcome have been reported in publications. 48 UKAs converted to a TKA between 1998 and 2009 were matched based on age, gender, and body mass index, pre-operative Knee Society Score, length of follow-up, and date of the index surgery to 48 primary TKAs and 48 revision TKAs. Surgical characteristics, clinical outcomes, and complications were compared at a mean follow-up of 7 ± 4 years. Even if a revision of UKA is technically less demanding than a revision TKA, functional scores, quality of life, complications and survival rate after revision UKA are more comparable to a revision than primary TKA.

Are revisions of patellofemoral arthroplasties more like primary or revision TKAs.

BACKGROUND: Patellofemoral arthroplasty (PFA) can be considered in patients with patellofemoral disease. However, the use of partial arthroplasty often causes concern among clinicians and patients that revision to total knee arthroplasty (TKA) will be needed and, if so, whether this revision will be straightforward or more complicated. QUESTIONS/PURPOSES: We set out to determine if conversion of a PFA to a TKA was more similar to a primary or to a revision TKA in terms of surgical characteristics, knee scores, range of motion, and complications. METHODS: Between 2001 and 2008, we revised 21 PFAs to TKAs, all of which were available for followup at a minimum of 5 years (median, 6 years; range, 5-12 years). These patients were matched one-to-one by age, sex, body mass index, length of followup, and preoperative Knee Society Scores (KSS) to 21 primary and 21 revision TKAs. We analyzed operative time and amount of blood loss. Clinical outcomes assessed were range of motion and KSS. RESULTS: Blood loss (405 mL versus 460 mL versus 900 mL; odds/hazard ratio, 1.33, 95% confidence interval [CI], 0.3-5.85; p=0.14 for primary TKA versus revision PFA and odds/hazard ratio, 0.13, 95% CI, 0.03-0.52; p<0.01 for revision PFA versus revision TKA) and operative time (52 minutes versus 72 minutes versus 115 minutes; odds/hazard ratio, 5.45, 95% CI, 1.23-27.4; p=0.02 for primary TKA versus revision PFA and odds/hazard ratio, 0.5, 95% CI, 0.01-0.44; p<0.001 for revision PFA versus revision TKA) were not different between the primary TKA and revision PFA groups but higher in the revision TKA group. KSS (knee and function) were higher in the primary TKA group (92 [range, 60-100] and 91 [range, 65-100]) than they were in the revision PFA (85 [range, 40-100] and 85 [range, 30-100]) and revision TKA groups (75 [range, 30-100] and 68 [range, 25-100]; p<0.001). Flexion was better in the primary TKA (125 [range, 105-130]) and revised PFA (120 [range, 100-130]) groups than the revision TKA group (105 [range, 80-115]; p=0.0013). There were more complications in the revision PFA group (two of 21) compared with the primary TKA group (zero of 21, p=0.005) but not compared with the revision TKA group (three of 21; p=0.85). CONCLUSIONS: With the numbers available, we found that revising a PFA is comparable to a primary TKA in regard to surgical characteristics and postoperative clinical outcomes (including knee scores and range of motion), and both are superior to revision TKA, although the frequency of complications was higher in the revision PFA group than it was in the primary TKA group. The majority of patients undergoing revision of a PFA to a TKA can be treated with a standard implant. LEVEL OF EVIDENCE: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

No benefit of patient-specific instrumentation in TKA on functional and gait outcomes: a randomized clinical trial.

BACKGROUND: Although some clinical reports suggest patient-specific instrumentation in TKA may improve alignment, reduce surgical time, and lower hospital costs, it is unknown whether it improves pain- and function-related outcomes and gait. QUESTIONS/PURPOSES: We hypothesized that TKA performed with patient-specific instrumentation would improve patient-reported outcomes measured by validated scoring tools and level gait as ascertained with three-dimensional (3-D) analysis compared with conventional instrumentation 3 months after surgery. METHODS: We randomized 40 patients into two groups using either patient-specific instrumentation or conventional instrumentation. Patients were evaluated preoperatively and 3 months after surgery. Assessment tools included subjective functional outcome and quality-of-life (QOL) scores using validated questionnaires (New Knee Society Score(©) [KSS], Knee Injury and Osteoarthritis Outcome Score [KOOS], and SF-12). In addition, gait analysis was evaluated with a 3-D system during level walking. The study was powered a priori at 90% to detect a difference in walking speed of 0.1 m/second, which was considered a clinically important difference, and in a post hoc analysis at 80% to detect a difference of 10 points in KSS. RESULTS: There were improvements from preoperatively to 3 months postoperatively in functional scores, QOL, and knee kinematic and kinetic gait parameters during level walking. However, there was no difference between the patient-specific instrumentation and conventional instrumentation groups in KSS, KOOS, SF-12, or 3-D gait parameters. CONCLUSIONS: Our observations suggest that patient-specific instrumentation does not confer a substantial advantage in early functional or gait outcomes after TKA. It is possible that differences may emerge, and this study does not allow one to predict any additional variances in the intermediate followup period from 6 months to 1 year postoperatively. However, the goals of the study were to investigate the recovery period as early pain and functional outcomes are becoming increasingly important to patients and surgeons. LEVEL OF EVIDENCE: Level I, therapeutic study. See the Instructions to Authors for a complete description of levels of evidence.

Modern unicompartmental knee arthroplasty with cement: a concise follow-up, at a mean of twenty years, of a previous report.

We previously evaluated the three to ten-year results of 160 consecutive unicompartmental knee arthroplasties that had been performed by two surgeons in 147 patients with use of the cemented metal-backed Miller-Galante prosthesis. The average age of the patients at the time of the index procedure was sixty-six years. The purpose of the present study was to report the updated results of this series after a mean duration of follow-up of twenty years. Sixty-two patients (seventy knees) were living, and seven had been lost to follow-up. Eleven knees had undergone conversion to total knee arthroplasty, three had had an addition of a patellofemoral prosthesis, and five had had polyethylene exchange. Ten knees had had revision since the three to ten-year evaluation. The reasons for revision included progression of osteoarthritis in twelve knees, aseptic loosening (which had been absent at the three to ten-year evaluation) in two knees, and polyethylene wear (which was treated with liner exchange at an average of twelve years) in five knees. The average clinical and functional Knee Society scores were 91 and 88 points, respectively, at the time of the latest follow-up. The average flexion was 127° (range, 80° to 145°). We concluded that modern cemented metal-backed unicompartmental implants, evaluated at a mean of twenty years of follow-up in patients with osteoarthritis that was limited to one tibiofemoral compartment of the knee, provided durable pain relief and long-term restoration of knee function without compromising future conversion to conventional total knee arthroplasty.

The outcome of rotating-platform total knee arthroplasty with cement at a minimum of ten years of follow-up.

BACKGROUND: Durable, long-term results have been reported for patients managed with first-generation mobile-bearing total knee arthroplasty. Second-generation mobile-bearing total knee arthroplasty has been introduced to enhance instrumentation, to increase flexion, and to improve functional outcome, but, to our knowledge, no long-term results are available. METHODS: From May 1999 to June 2000, 116 consecutive rotating-platform total knee arthroplasties were performed by the two senior authors in 112 patients with use of the LPS-Flex Mobile cemented prosthesis, which was implanted with a measured resection technique. The patella was resurfaced in every knee. The average age of the patients at the time of surgery was sixty-nine years (range, thirty-seven to eighty-five years), and seventy-seven patients (eighty knees) were women. The predominant diagnosis was osteoarthritis. The clinical and radiographic evaluation was performed with use of the Knee Society rating system. The level of activity and patient-reported functional outcome were evaluated with use of the University of California at Los Angeles (UCLA) score and the Knee injury and Osteoarthritis Outcome Score (KOOS), respectively. RESULTS: The average duration of follow-up was 10.6 years (range, ten to 11.8 years). Three patients were lost to follow-up, and five patients died of causes unrelated to knee arthroplasty. Two knees were revised, one because of infection and one because of failure of the medial collateral ligament. Kaplan-Meier survivorship analysis showed an implant survival rate of 98.3% at ten years. For the 104 patients (108 knees) who were evaluated at a minimum of ten years, the average Knee Society knee and function scores improved from 34 to 94 points and from 55 to 88 points, respectively, at the time of the latest follow-up. There was no periprosthetic osteolysis and no evidence of implant loosening on follow-up radiographs. The average knee flexion was 117° preoperatively and 128° at the time of the latest follow-up evaluation. At the time of the latest follow-up, the KOOS quality-of-life score was significantly better for patients with >125° of flexion (p = 0.00034). CONCLUSIONS: This study demonstrated durable clinical and radiographic results at a minimum of ten years after total knee replacement with a second-generation, cemented, rotating-platform, posterior-stabilized total knee prosthesis. According to the functional outcome results obtained in this study, we believe that this design is a valuable option for active patients undergoing total knee arthroplasty.

No long-term difference between fixed and mobile medial unicompartmental arthroplasty.

BACKGROUND: Early studies in the literature reported relatively high early minor reintervention rate for the mobile-bearing unilateral knee arthroplasty (UKA) compared with short- and midterm survivorship after fixed- or mobile-bearing UKA. However, whether the long-term function and survivorship are similar is unclear. QUESTIONS/PURPOSES: We therefore asked whether (1) mobile- or fixed-bearing UKAs have comparable function (as measured by the Knee Society scores); (2) mobile- and fixed-bearing UKA have comparable Knee Society radiographic scores; and (3) the long-term survivorship is comparable. METHODS: We retrospectively reviewed 75 patients (79 knees) with a fixed-bearing UKA and 72 patients (77 knees) with a mobile-bearing UKA operated on between 1989 and 1992. Mean age of the patients was 63 years; gender and body mass index (26 kg/m(2)) were comparable in the two groups. We obtained Knee Society function and radiographic scores and determined survival. The minimum followup was 15 years (mean, 17.2 ± 4.8 years; range, 15-21.2 years). RESULTS: The mean Knee Society function and knee scores were comparable in the two groups. Radiographically, the number of overcorrections and the number of radiolucencies were statistically higher in the mobile-bearing group (69% versus 24%). At final followup, considering revision for any reason, 12 of 77 (15%) UKAs were revised (for aseptic loosening, dislocation, and arthritis progression) in the mobile-bearing group and 10 of 79 (12%) in the fixed-bearing group (for wear and arthritis progression). CONCLUSIONS: This long-term study did not demonstrate any difference in survivorship between fixed and mobile-bearing but pointed out specific modes of failure.

Survival of bicompartmental knee arthroplasty at 5 to 23 years.

UNLABELLED: Recent literature suggests patients achieve substantial short-term functional improvement after combined bicompartmental implants but longer-term durability has not been documented. We therefore asked whether (1) bicompartmental arthroplasty (either combined medial unicompartmental knee arthroplasty (UKA) and femoropatellar arthroplasty (PFA) or medial UKA/PFA, or combined medial and lateral UKA or bicompartmental UKA) reliably improved Knee Society pain and function scores; (2) bicompartmental arthroplasty was durable (survivorship, radiographic loosening, or symptomatic disease progression); (3) we could achieve durable alignment; and (4) the arthritis would progress in the unresurfaced compartment. We retrospectively reviewed 84 patients (100 knees) with bicompartmental UKA and 71 patients (77 knees) with medial UKA/PFA. Clinical and radiographic evaluations were performed at a minimum followup of 5 years (mean, 12 years; range, 5-23 years). Bicompartmental arthroplasty reliably alleviated pain and improved function. Prosthesis survivorship at 17 years was 78% in the bicompartmental UKA group and 54% in the medial UKA/PFA group. The high revision rate, compared with total knee arthroplasty, may be related to several factors such as implant design, patient selection, crude or absent instrumentation, or component malalignment, which can all contribute to the relatively high failure rate in this series. LEVEL OF EVIDENCE: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Long-term results with a lateral unicondylar replacement.

UNLABELLED: While the literature suggests lateral unicondylar knee arthroplasty (UKA) improves function in the short- and medium-term, it is less clear on longer-term function. We asked (1) whether lateral UKA improved longer-term Knee Society scores and return to previous activity level); (2) whether there were any concerning longer-term radiographic findings (the Knee Society roentgenographic evaluation and scoring system); and (3) whether lateral UKA was durable as measured by survivorship to revision at 10 and 16 years. We retrospectively reviewed 39 patients with 40 lateral cemented metal-backed UKA. The patients had a mean age of 61 years at surgery. The etiologies were primary osteoarthritis in 24 knees, posttraumatic in 12 cases, and osteonecrosis in four cases. We performed clinical and radiographic evaluations at a minimum followup of 3 years (mean, 12.6 years; range, 3-23 years). Prostheses survivorship was 92% at 10 years and 84% at 16 years. Despite the limited number of indications and technical considerations, our data suggest lateral UKA is a reasonable alternative for isolated lateral femorotibial compartment disease. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Anatomy of the dysplastic hip and consequences for total hip arthroplasty.

Total hip arthroplasty in dysplastic hips is challenging because of the modified anatomy of the proximal femur and acetabulum. We studied three-dimensional anatomic parameters in 247 dysplastic hips from 218 adult patients using radiographs and computed tomography, and analyzed the consequences for total hip arthroplasty. A cohort of 310 primary osteoarthritic hips was used as a control group. According to the classification of Crowe et al, 78 of the dislocated hips were graded Class I, 26 as Class II, 20 as Class III or IV, and 169 dysplastic hips had no subluxation. Compared with primary osteoarthritis, the intramedullary femoral canal had reduced mediolateral and anteroposterior dimensions. With high grade subluxations the femoral neck shaft angle decreased but with low grades, especially in Class II, the neck shaft angle increased. The proximal femur had more anteversion with individual variations ranging from 1 degrees to 80 degrees. The true acetabulum had a reduced anteroposterior diameter. The large individual morphologic variability across all levels of dysplastic hips suggests the femoral prosthesis cannot be chosen on the basis of the severity of the subluxation alone.

Unicompartmental knee arthroplasty for avascular osteonecrosis.

UNLABELLED: The data analyzing clinical and radiological outcomes after modern unicompartmental knee arthroplasty (UKA) for spontaneous and secondary avascular osteonecrosis are limited. We determined whether: (1) UKA for osteonecrosis was as reliable for alleviating pain and improving function (measured by Knee Society scores) as it is for osteoarthritis, (2) lower limb alignment could be restored after UKA for osteonecrosis, and (3) UKA for osteonecrosis is as durable as UKA for osteoarthritis (measured by survivorship at 12 years). We retrospectively reviewed 30 patients (31 knees) with osteonecrosis; 21 knees had spontaneous osteonecrosis and 10 had secondary osteonecrosis. Mean patient age was 71 years. Clinical and radiological evaluations were performed by an independent observer at a minimum followup of 3 years (mean, 7 years; range, 3-16 years). Reliable pain relief and function improvement were obtained in 30 knees (96%). Restoration of an appropriate lower-limb mechanical axis was achieved for 27 knees (88%). The Kaplan-Meier survivorship was 96.7% at 12 years. Our data suggest UKA is a reasonable solution for restoring clinical function and radiological lower-limb alignment for spontaneous or secondary osteonecrosis limited to one compartment of the knee, with a durable survivorship. LEVEL OF EVIDENCE: Level IV, retrospective study. See the Guidelines for Authors for a complete description of levels of evidence.