The natural history of radiolucencies following cemented unicompartmental knee arthroplasty at 7 years.

INTRODUCTION: Radiolucent lines (RLLs) following unicompartmental knee arthroplasty (UKA) can be concerning as aseptic loosening remains a cause of failure in UKA. The aim of our study was to report on the history of RLLs surrounding the components in a cemented medial compartment fixed-bearing UKA as well as the long-term functional outcomes in this group of patients. MATERIAL AND METHODS: In this retrospective consecutive case-series, twenty-eight patients (37 knees) were treated with medial, fixed-bearing cemented unicompartmental knee arthroplasty. At average final follow-up of 7.1 years, 36 knees were available for review. Radiographs were taken at six weeks, one year, and final follow up. RLLs were measured using a novel modification to the Knee Society scoring (KSS) system. RESULTS: At six-weeks, we identified RLLs in 26 tibias and two femurs out of 37 total knees. At one-year, four additional tibias and both femurs showed some progression of their radiolucencies but were < 2 mm total. At final follow-up, 31 of the 36 tibias (86.1%) and five of the 36 femurs (13.9%) had any RLLs. On the tibial side, RLLs were most common in medial/lateral and anterior/posterior aspects of the tibial tray with few found centrally. On the femoral side, the posterior femoral cut accounted for the most RLLs of any zone at all time points. KSS averaged 93.8 at final follow-up and none of the patients required revision surgery. CONCLUSION: RLLs are common following cemented, fixed-bearing UKA. Many seem to progress slowly up to one year but not thereafter. There does not appear to be any association between the presence of these radiolucencies and long-term follow-up function in this group of patients.

Poor Patient Follow-up After Metal-on-Metal Total Hip Arthroplasty.

Routine follow-up approximately every 2 to 5 years after total hip arthroplasty (THA) is a common practice. However, although patients are informed of the importance of follow-up, our mean follow-up rate for patients after standard non-metal-on-metal (MOM) THA is only 19%. The US Food and Drug Administration has released several statements on the importance of follow-up every 2 years after MOM THA. With the potential risks of MOM THA apparently widely known, we report on our ability to obtain timely follow-up at 2 separate centers. Two separate centers performed 570 MOM THA procedures between 2002 and 2010. An attempt was made to reach every patient by either telephone or letter to obtain ion levels, radiographs, and examinations. Repeat telephone calls and/or letters to those not reached were made annually. Patients were told of the unique importance of follow-up at each contact. Of the patients, 43% had not been seen within the past 5 years, and only 26% had been seen within the past 2 years. Only 61% had their first measurement of ion levels, and only 30% of patients had a second set of measurement of ion levels. A total of 48 revisions occurred in this group, and 36 patients died. Despite the apparent widespread dissemination of information regarding the potential risks of MOM THA and concerted efforts to contact patients for follow-up, we have been able to achieve a follow-up rate of only 26%. This rate is only marginally better than the mean follow-up for non-MOM THA in our practices. The implications of this poor follow-up are unknown. [Orthopedics. 2022;45(4):e196-e200.].

Average narcotic usage in a group of TKA patients following a modern TKA protocol.

INTRODUCTION: The optimal dosing of post-operative total knee arthroplasty (TKA) narcotics is unclear. We report on the average narcotic usage in a group of patients treated with an identical multimodal pain protocol following TKA. MATERIALS AND METHODS: 49 patients undergoing TKA participated in the survey. Patients with pre-op narcotic use, recent prior total joint arthroplasty or study refusal were excluded. All patients received a spinal anesthetic. No pre-surgery narcotics were given. All received an identical local infiltrative anesthetic combination along with a multimodal pain protocol. Patients were placed into an identical rapid rehab program. Narcotic usage during hospitalization was recorded in morphine equivalent doses (MED). Patients were given a journal to record their daily narcotic utilization. RESULTS: Pre-operative pain scores of the excluded groups had slightly higher but clinically insignificant differences compared to the study group. In the hospital, POD1 study group daily MED averaged 28 (range 0-110). POD2 had an average of 33.6 and POD 3 daily usages averaged 28.6 (range 0-100). By the end of week two, the average daily use was 19.2 and 24% patients were off all narcotics. By the end of week four, the average daily usage was 7.5 and 63% of patients were off all narcotics. By 8 weeks, there were no patients still taking narcotics. KSS averaged 76.9 (range 51-97) at the 6 week visit, and 94.2 at the 3-month visit (range 72-100). SUMMARY: This study documents the average needs of an average TKA patient treated with modern pain protocols. The majority of these patients were off narcotics by week four.

Modern full-component aseptic revision total knee arthroplasties have similar recoveries compared with primary total knee arthroplasty patients when applying an enhanced recovery anaesthetic and analgesic protocol.

AIMS: Enhanced perioperative protocols have significantly improved patient recovery following primary total knee arthroplasty (TKA). Little has been investigated the effectiveness of these protocols for revision TKA (RTKA). We report on a matched group of aseptic revision and primary TKA patients treated with an identical pain and rehabilitation programmes. METHODS: Overall, 40 aseptic full-component RTKA patients were matched (surgical date, age, sex, and body mass index (BMI)) to a group of primary cemented TKA patients. All RTKAs had new uncemented stemmed femoral and tibial components with metaphyseal sleeves. Both groups were treated with an identical postoperative pain protocol. Patients were followed for at least two years. Knee Society Scores (KSS) at six weeks and at final follow-up were recorded for both groups. RESULTS: There was no difference in mean length of stay between the primary TKA (1.2 days (0.83 to 2.08)) and RTKA patients (1.4 days (0.91 to 2.08). Mean oral morphine milligram (mg) equivalent dosing (MED) during the hospitalization was 42 mg/day for the primary TKA and 38 mg/day for the RTKA groups. There were two readmissions: gastrointestinal disturbance (RTKA) and urinary retention (primary TKA). There no were reoperations, wound problems, thromboembolic events or manipulations in either group. Mean overall KSS for the RTKA group was 87.3 (45 to 99) at six-week follow-up and 89.1 (52 to 100) at final follow-up (mean 3.9 years, (3.9 to 9.0)). Mean overall KSS for the primary group was 89.9 (71 to 100) at six-week follow-up and 93.42 (73 to 100) at final follow-up (mean 3.5 years (2.5 to 9.2)). CONCLUSION: An identical pain and rehabilitation protocol used for primary TKA patients can enable certain full-component aseptic RTKA patients to have a similar early functional outcome. Cite this article: Bone Joint J 2020;102-B(6 Supple A):96-100.

The Natural History of Radiolucencies Following Uncemented Total Knee Arthroplasty at 9 Years.

BACKGROUND: Aseptic loosening remains a common cause of failure in total knee arthroplasty (TKA). There is an increased interest in using uncemented TKA to reduce this complication. Radiolucencies (RLs) following uncemented TKA can be concerning. We report on the 9-year history of RLs in patients with uncemented TKA. METHODS: Twenty-one patients (26 knees) were treated with a cruciate-retaining fully porous coated femur/tibia and cemented patella. At final follow-up, 17 patients (22 knees) were available for review. Average follow-up was 9.6 years, average age was 59.1, and average body mass index was 34.1. X-rays were taken at 6 weeks, 1 year, and at final follow-up. RLs were measured using the Knee Society scoring system and read by two separate surgeons. RESULTS: At 6 weeks, we identified RL in all patients on both the tibia and femur. The majority were beneath the tibial tray and femoral chamfer. At 1 year, 4 femurs and 4 tibias showed new RLs (<2 mm) in similar zones. Eighteen femurs and 18 tibias showed fewer or no change in RLs. At final follow-up, no new tibia or femur developed a new RL. In total, 9 of the 22 tibias and 17 of the 22 femurs had remaining RLs, all less than 2 mm and none were progressive or new. Knee Society Score averaged 92.5 (6 weeks), 95.1 (1 year), and 97.3 (final). CONCLUSION: RLs are common following uncemented TKA. Many resolve by 1 year. There does not appear to be any association between the presence of RLs and long-term follow-up function in this group of patients.

Ignore the Patella in Revision Total Knee Surgery: A Minimum 5-Year Follow-Up With Patella Component Retention.

BACKGROUND: In the setting of aseptic revision, a common question is: what should be done with the previously resurfaced patella? We report on a series of aseptic revision total knee arthroplasties (RTKA) where one or both components were revised and the patella was not. METHODS: The study group was 147 consecutive RTKA in 137 patients with a mean age of 70.1 ± 9.3 years where the patella was not revised. The average body mass index was 31.0 ± 5.4 kg/m2. Follow-up was a minimum of 5 years (range, 5 to 12 years). At final follow-up, 13 patients died and 2 patients were lost to follow-up leaving 122 patients and 130 knees available for review. Mean time from primary surgery to RTKA was 9.2 ± 5.5 years. Both components were revised in 50 knees, the femur only in 11 knees, the tibia only in 12 knees, and 57 had an isolated polyethylene revision. We found 5 patients with a mismatch between the patella and femoral components and 30 cases with patella component wear identified intraoperatively. RESULTS: At final follow-up, there were no reoperations on any patella and none were at risk of failure. There were 6 knees with a lateral patella tilt beyond 10°, but none were subluxed. Knee Society Scores averaged 85 ± 17.2 points at final follow-up. CONCLUSION: At midterm follow-up in this group of RTKA where the patella was not revised, we identified no subsequent failures of the patella. This is despite the presence of mild patella polyethylene wear and mismatched shapes in several knees. LEVEL OF EVIDENCE: III.

Incidence of Patella Baja Before and After Primary Total Knee Arthroplasty Based on Body Mass Index.

In the setting of total knee arthroplasty, patella baja has been associated with decreased range of motion and increased risk of certain extensor mechanism complications. The goal of this study was to determine whether obese patients had an increased prevalence of patella baja before and/or after primary total knee arthroplasty. A multicenter retrospective review of 5089 unilateral total knee arthroplasties performed between 1998 and 2012 for osteoarthritis was conducted. Only total knee arthroplasties with cemented modular, metal-backed constructs and patellar resurfacing were included. An a priori power analysis determined that 500 patients (stratified into 5 World Health Organization body mass index groups, matched by age and sex) were needed to detect a significant Insall-Salvati ratio difference of 0.07. Patella baja was defined as an Insall-Salvati ratio of less than 0.8. Preoperative and postoperative Insall-Salvati ratios were compared between groups and analyzed using linear regression and analysis of variance. Preoperatively, there was a higher prevalence of patella baja in the higher body mass index groups (>25 kg/m2) compared with normal weight patients (10% vs 6%; P=.02). Postoperatively, there was no difference in the prevalence of patella baja between the 2 groups (5% vs 5%; P=.91). On comparison of postoperative Insall-Salvati ratio with preoperative Insall-Salvati ratio, the higher body mass index groups had a greater change in Insall-Salvati ratio (Δ 0.10 vs Δ 0.07; P=.01). This is the first study to report an increased prevalence of patella baja in obese patients and to show that the prevalence normalizes to that of a control group after total knee arthroplasty. Obese patients undergoing primary total knee arthroplasty had a higher rate of preoperative patella baja. [Orthopedics. 2019; 42(2):90-94.].

Right TKR Patients Treated with Enhanced Pain and Rehabilitation Protocols Can Drive at 2 Weeks.

An important milestone in the recovery following total knee replacement (TKR) is the ability to return to driving. With advances in pain control and the widespread introduction of rapid rehab programs, we hypothesized that the ability to drive would also return sooner than had been traditionally observed. In our group of consecutive right TKR patients, using a driving simulator, we showed that at the 2-week mark, 36 of the 40 patients tested had returned to their preoperative driving capabilities and the other 4 had reached baseline at 3 weeks. While the eventual decision to return to driving is complex and dependent on many factors, we conclude that one of the benefits of enhanced pain and rehab protocols is that patients undergoing right TKR can return to driving in most instances at the 2-week mark rather than the traditional 6-week mark.