Increased risk for early revision with quadriceps graft compared with patellar tendon graft in primary ACL reconstructions.

PURPOSE: Bone patella-tendon bone (BPTB) and hamstring tendon (HT) autografts are the most used grafts in primary anterior cruciate ligament (ACL) reconstructions (ACLR) in Norway. Quadriceps tendon (QT) autograft has gained more popularity during the past years. The purpose of this study is to compare revision rates and patient-reported outcomes of primary QT with BPTB and HT autograft ACL reconstructions in Norway at 2-year follow-up. It was hypothesized that there would be no difference in 2-year revision rates between all three autografts. METHODS: Data included primary ACLR without concomitant ligament surgeries, registered in the Norwegian Knee Ligament Register from 2004 through 2021. Revision rates at 2 years were calculated using Kaplan-Meier analysis. Hazard ratios (HR) for revision were estimated using multivariable Cox regression analysis with revision within 2 years as endpoint. Mean change in patient-reported outcome was recorded preoperatively and at 2 years through the Knee Injury and Osteoarthritis Outcome Score (KOOS) subcategories 'Sport' and 'Quality of Life' was measured for patients that were not revised and analysed with multiple linear regression. RESULTS: A total of 24,790 primary ACLRs were identified, 10,924 with BPTB, 13,263 with HT and 603 with a QT graft. Patients in the QT group were younger (23.5 years), more of them were women (58.2%) and over 50% had surgery <3 months after injury. The QT group had the highest prevalence of meniscal injuries (61.9%). Revision estimates at 2-years were 3.6%, 2.5% and 1.2% for QT, HT and BPTB, respectively (p < 0.001). In a Cox regression analysis with QT as reference, BPTB had a lower risk of revision (HR 0.4, 95% Cl 0.2-0.7, p < 0.001). No significant difference was observed in the revision risk between QT and HT (HR 1.1, 95% Cl 0.7-1.8, n.s.). The two most common reported reasons for revision were: traumatic graft rupture and nontraumatic graft failure. There were no differences between the groups in change of KOOS in subcategories 'Sport' and 'Quality of Life' at 2-years follow-up. CONCLUSION: The 2-year risk of revision after ACLR with QT was higher than BPTB and similar to HT. No difference was found between the groups in patient-reported outcomes. This study provides valuable insights for both surgeons and patients when making decisions about the choice of autografts in primary ACL reconstructions. LEVEL OF EVIDENCE: Level II.

Previous cartilage surgery is associated with inferior patient-reported outcomes after knee arthroplasty.

PURPOSE: The hypothesis of the present study assumed that a history of focal cartilage lesions would not affect Knee Injury and Osteoarthritis Outcome scores (KOOSs) following knee arthroplasty compared to a matched national cohort of knee arthroplasty patients. METHODS: Fifty-eight knee arthroplasty patients with previous surgery for focal cartilage lesions (cartilage cohort) were compared to a matched cohort of 116 knee arthroplasty patients from the Norwegian Arthroplasty Register (control group). Age, sex, primary or revision arthroplasty, type of arthroplasty (total, unicondylar or patellofemoral), year of arthroplasty surgery and arthroplasty brand were used as matching criteria. Demographic data and KOOS were obtained through questionnaires. Regression models were employed to adjust for confounding factors. RESULTS: Mean follow-up post knee arthroplasty surgery was 7.6 years (range 1.2-20.3) in the cartilage cohort and 8.1 (range 1.0-20.9) in the control group. The responding patients were at the time of surgery 54.3 versus 59.0 years in the cartilage and control group, respectively. At follow-up the control group demonstrated higher adjusted Knee Injury and Osteoarthritis Outcome subscores than the previous focal cartilage patients with a mean adjusted difference (95% confidence interval in parentheses): Symptoms 8.4 (0.3, 16.4), Pain 11.8 (2.2, 21.4), Activities of daily living (ADL) 9.3 (-1.2, 18.6), Sport and recreation 8.9 (-1.6, 19.4) and Quality of Life (QoL) 10.6 (0.2, 21.1). The control group also demonstrated higher odds of reaching the patient-acceptable symptom state threshold for the Knee Injury and Osteoarthritis Outcome subscores with odds ratio: Symptoms 2.7 (1.2, 6.4), Pain 3.0 (1.3, 7.0), ADL 2.1 (0.9, 4.6) and QoL 2.4 (1.0, 5.5). CONCLUSION: Previous cartilage surgery was associated with inferior patient-reported outcomes after knee arthroplasty. These patients also exhibited significantly lower odds of reaching the patient-acceptable symptom state threshold for the Knee Injury and Osteoarthritis Outcome subscores. LEVEL OF EVIDENCE: Level III.

Risk factors for revision surgery due to dislocation within 1 year after 111,711 primary total hip arthroplasties from 2005 to 2019: a study from the Norwegian Arthroplasty Register.

BACKGROUND AND PURPOSE: Dislocation of a hip prosthesis is the 3rd most frequent cause (after loosening and infection) for hip revision in Norway. Recently there has been a shift in surgical practice including preferred head size, surgical approach, articulation, and fixation. We explored factors associated with the risk of revision due to dislocation within 1 year and analyzed the impact of changes in surgical practice. PATIENTS AND METHODS: 111,711 cases of primary total hip arthroplasty (THA) from the Norwegian Arthroplasty Register were included (2005-2019) after primary THA with either 28 mm, 32 mm, or 36 mm femoral heads, or dualmobility articulations. A flexible parametric survival model was used to calculate hazard ratios for risk factors. Kaplan-Meier survival rates were calculated. RESULTS: There was an increased risk of revision due to dislocation with 28 mm femoral heads (HR 2.6, 95% CI 2.0-3.3) compared with 32 mm heads. Furthermore, there was a reduced risk of cemented fixation (HR 0.6, CI 0.5-0.8) and reverse hybrid (HR 0.6, CI 0.5-0.8) compared with uncemented. Also, both anterolateral (HR 0.5, CI 0.4-0.7) and lateral (HR 0.6, CI 0.5-0.7) approaches were associated with a reduced risk compared with the posterior approach. The time-period 2010-2014 had the lowest risk of revision due to dislocation. The trend during the study period was towards using larger head sizes, a posterior approach, and uncemented fixation for primary THA. INTERPRETATION: Patients with 28 mm head size, a posterior approach, or uncemented fixation had an increased risk of revision due to dislocation within 1 year after primary THA. The shift from lateral to posterior approach and more uncemented fixation was a plausible explanation for the increased risk of revision due to dislocation observed in the most recent time-period. The increased risk of revision due to dislocation was not fully compensated for by increasing femoral head size from 28 to 32 mm.

Antibiotic-Loaded Bone Cement in Prevention of Periprosthetic Joint Infections in Primary Total Knee Arthroplasty: A Register-based Multicentre Randomised Controlled Non-inferiority Trial (ALBA trial).

INTRODUCTION: The current evidence on the efficacy of antibiotic-loaded bone cement (ALBC) in reducing the risk of periprosthetic joint infections (PJI) after primary joint reconstruction is insufficient. In several European countries, the use of ALBC is routine practice unlike in the USA where ALBC use is not approved in low-risk patients. Therefore, we designed a double-blinded pragmatic multicentre register-based randomised controlled non-inferiority trial to investigate the effects of ALBC compared with plain bone cement in primary total knee arthroplasty (TKA). METHODS AND ANALYSIS: A minimum of 9,172 patients undergoing full-cemented primary TKA will be recruited and equally randomised into the ALBC group and the plain bone cement group. This trial will be conducted in Norwegian hospitals that routinely perform cemented primary TKA. The primary outcome will be risk of revision surgery due to PJI at 1-year of follow-up. Secondary outcomes will be: risk of revision due to any reason including aseptic loosening at 1, 6, 10 and 20 years of follow-up; patient-related outcome measures like function, pain, satisfaction and health-related quality of life at 1, 6 and 10 years of follow-up; risk of changes in the microbial pattern and resistance profiles of organisms cultured in subsequent revisions at 1, 6, 10 and 20 years of follow-up; cost-effectiveness of routine ALBC versus plain bone cement use in primary TKA. We will use 1:1 randomisation with random permuted blocks and stratify by participating hospitals to randomise patients to receive ALBC or plain bone cement. Inclusion, randomisation and follow-up will be through the Norwegian Arthroplasty Register. ETHICS AND DISSEMINATION: The trial was approved by the Western Norway Regional Committees on Medical and Health Research Ethics (reference number: 2019/751/REK vest) on 21 June 2019. The findings of this trial will be disseminated through peer-reviewed publications and conference presentations. TRIAL REGISTRATION NUMBER: NCT04135170.

No effect of graft size or body mass index on risk of revision after ACL reconstruction using hamstrings autograft.

PURPOSE: The current study investigated the distribution of hamstrings graft size and body mass index and any potential effect on the risk of revision surgery in a large prospective cohort of patients undergoing ACL reconstruction. More specifically, the aim of the study was to investigate whether larger graft size or smaller BMI would decrease the risk of revision after ACL reconstruction. METHODS: A total of 4029 patients, prospectively registered in the Norwegian Knee Ligament Registry, were included in the study. Univariate Kaplan-Meier survival analyses (with log-rank tests) and the Cox proportional hazard (PH) regression model were applied to compare risk of revision between groups of patients. Mutual adjustment for gender, age, activity at the time of injury and fixation method of the graft was performed. RESULTS: Graft sizes spanned from 5.5 to 11.0 mm and the median of 8.0 mm was reported in 42% of patients in the cohort. BMI was reported from 15 to 57 with a median of 25. 46% of patients were classified as overweight (WHO standards), while 23% of patients were obese. At a median of 2.5 years after surgery, 150 patients had undergone revision surgery. Although certain effects were seen in the unadjusted analyses, neither graft size (diameter) nor patient BMI did affect the risk of undergoing revision surgery in the adjusted analyses. CONCLUSIONS: Graft size and BMI was not found to be independent risk factors for undergoing ACL revision surgery. In contrast to other studies, graft size of 8 mm or larger did not have a better outcome than smaller graft sizes. A relatively large group of overweight patients undergoing ACL surgery reflects the general increase in weight seen in Western societies. Although the current study differs from previous findings, it might indicate that graft diameter is less important than previously stated. LEVEL OF EVIDENCE: Cohort study, II.

Correction to: No effect of graft size or body mass index on risk of revision after ACL reconstruction using hamstrings autograft.

Unfortunately, the author Jon Olav Drogset was incorrectly published in the original version and updated here. The original article has been corrected.

A Controlled Comparison of Microfracture, Debridement, and No Treatment of Concomitant Full-Thickness Cartilage Lesions in Anterior Cruciate Ligament-Reconstructed Knees: A Nationwide Prospective Cohort Study From Norway and Sweden of 368 Patients With 5-Year Follow-up.

BACKGROUND: The effect of microfracture (MF) or surgical debridement of concomitant full-thickness cartilage lesions in anterior cruciate ligament-reconstructed knees on patient-reported outcomes remains to be determined. PURPOSE: To evaluate the effect of debridement or MF compared with no surgical treatment of concomitant full-thickness cartilage lesions on patient-reported outcomes 5 years after anterior cruciate ligament reconstruction (ACLR). STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Included in this study were 644 patients who were registered in the Norwegian and the Swedish National Knee Ligament Registries from 2005 to 2008 as having undergone unilateral primary ACLR and having a concomitant full-thickness cartilage lesion (International Cartilage Repair Society [ICRS] grades 3-4). Of these patients, 129 were treated with debridement, 164 were treated with MF, and 351 received no surgical treatment simultaneously with ACLR. At 5-year follow-up, 368 (57%) patients completed results on the Knee injury and Osteoarthritis Outcome Score (KOOS). Multivariable linear regression was used to estimate the effect of surgical debridement or MF of concomitant full-thickness cartilage lesions on patient-reported outcomes 5 years after ACLR. RESULTS: Compared with no surgical treatment, there were no unadjusted or adjusted effects of debridement or MF of concomitant full-thickness cartilage lesions on KOOS scores at 5-year follow-up. CONCLUSION: Compared with leaving concomitant full-thickness cartilage lesions untreated at the time of ACLR, debridement and MF showed no effect on patient-reported outcomes 5 years after surgery.

Risk of Revision Was Not Reduced by a Double-bundle ACL Reconstruction Technique: Results From the Scandinavian Registers.

BACKGROUND: Double-bundle anterior cruciate ligament (ACL) reconstruction has demonstrated improved biomechanical properties and moderately better objective outcomes compared with single-bundle reconstructions. This could make an impact on the rerupture rate and reduce the risk of revisions in patients undergoing double-bundle ACL reconstruction compared with patients reconstructed with a traditional single-bundle technique. The National Knee Ligament Registers in Scandinavia provide information that can be used to evaluate the revision outcome after ACL reconstructions. QUESTIONS/PURPOSES: The purposes of the study were (1) to compare the risk of revision between double-bundle and single-bundle reconstructions, reconstructed with autologous hamstring tendon grafts; (2) to compare the risk of revision between double-bundle hamstring tendon and single-bundle bone-patellar tendon-bone autografts; and (3) to compare the hazard ratios for the same two research questions after Cox regression analysis was performed. METHODS: Data collection of primary ACL reconstructions from the National Knee Ligament Registers in Denmark, Norway, and Sweden from July 1, 2005, to December 31, 2014, was retrospectively analyzed. A total of 60,775 patients were included in the study; 994 patients were reconstructed with double-bundle hamstring tendon grafts, 51,991 with single-bundle hamstring tendon grafts, and 7790 with single-bundle bone-patellar tendon-bone grafts. The double-bundle ACL-reconstructed patients were compared with the two other groups. The risk of revision for each research question was detected by the risk ratio, hazard ratio, and the corresponding 95% confidence intervals. Kaplan-Meier analysis was used to estimate survival at 1, 2, and 5 years for the three different groups. Furthermore, a Cox proportional hazard regression model was applied and the hazard ratios were adjusted for country, age, sex, meniscal or chondral injury, and utilized fixation devices on the femoral and tibial sides. RESULTS: There were no differences in the crude risk of revision between the patients undergoing the double-bundle technique and the two other groups. A total of 3.7% patients were revised in the double-bundle group (37 of 994 patients) versus 3.8% in the single-bundle hamstring tendon group (1952 of 51,991; risk ratio, 1.01; 95% confidence interval (CI), 0.73-1.39; p = 0.96), and 2.8% of the patients were revised in the bone-patellar tendon-bone group (219 of the 7790 bone-patellar tendon-bone patients; risk ratio, 0.76; 95% CI, 0.54-1.06; p = 0.11). Cox regression analysis with adjustment for country, age, sex, menisci or cartilage injury, and utilized fixation device on the femoral and tibial sides, did not reveal any further difference in the risk of revision between the single-bundle hamstring tendon and double-bundle hamstring tendon groups (hazard ratio, 1.18; 95% CI, 0.85-1.62; p = 0.33), but the adjusted hazard ratio showed a lower risk of revision in the single-bundle bone-patellar tendon-bone group compared with the double-bundle group (hazard ratio, 0.62; 95% CI, 0.43-0.90; p = 0.01). Comparisons of the graft revision rates reported separately for each country revealed that double-bundle hamstring tendon reconstructions in Sweden had a lower hazard ratio compared with the single-bundle hamstring tendon reconstructions (hazard ratio, 1.00 versus 1.89; 95% CI, 1.09-3.29; p = 0.02). Survival at 5 years after index surgery was 96.0% for the double-bundle group, 95.4% for the single-bundle hamstring tendon group, and 97.0% for the single-bundle bone-patellar tendon-bone group. CONCLUSIONS: Based on the data from all three national registers, the risk of revision was not influenced by the reconstruction technique in terms of using single- or double-bundle hamstring tendons, although national differences in survival existed. Using bone-patellar tendon-bone grafts lowered the risk of revision compared with double-bundle hamstring tendon grafts. These findings should be considered when deciding what reconstruction technique to use in ACL-deficient knees. Future studies identifying the reasons for graft rerupture in single- and double-bundle reconstructions would be of interest to understand the findings of the present study. LEVEL OF EVIDENCE: Level III, therapeutic study.

A follow-up study of airway symptoms and lung function among residents and workers 5.5 years after an oil tank explosion.

BACKGROUND: Assess if people who lived or worked in an area polluted after an oil tank explosion had persistent respiratory health impairment as compared to a non-exposed population 5.5 years after the event. METHODS: A follow-up study 5.5 years after the explosion, 330 persons aged 18-67 years, compared lung function, lung function decline and airway symptoms among exposed persons (residents <6 km from the accident site or working in the industrial harbour at the time of the explosion) with a non-exposed group (residence >20 km away). Also men in the exposed group who had participated in accident related tasks (firefighting or clean-up of pollution) were compared with men who did not. Data were analysed using Poisson regression, adjusted for smoking, occupational exposure, atopy and age. RESULTS: Exposed men who had participated in accident related tasks had higher prevalence of lower airway symptoms after 5.5 years (n = 24 [73%]) than non-exposed men (28 [48%]), (adjusted relative risk 1.51 [95% confidence interval 1.07, 2.14]). Among men who participated in accident related tasks FEV1 decline was 48 mL per year, and 12 mL among men who did not (adjusted difference -34 mL per year [-67 mL, -1 mL]), and at follow-up FEV1/FVC ratio was 71.4 and 74.2% respectively, (adjusted difference -3.0% [-6.0, 0.0%]). CONCLUSION: Residents and workers had more airway symptoms and impaired lung function 5.5 years after an oil tank explosion, most significant for a group of men engaged in firefighting and clean-up of pollution after the accident. Public health authorities should be aware of long-term consequences after such accidents.

Better survival of hybrid total knee arthroplasty compared to cemented arthroplasty.

BACKGROUND AND PURPOSE: There have been few comparative studies on total knee replacement (TKR) with cemented tibia and uncemented femur (hybrid TKR). Previous studies have not shown any difference in revision rate between cemented and hybrid fixation, but these studies had few hybrid prostheses. We have evaluated the outcome of hybrid TKR based on data from the Norwegian Arthroplasty Register (NAR). PATIENTS AND METHODS: We compared 4,585 hybrid TKRs to 20,095 cemented TKRs with risk of revision for any cause as the primary endpoint. We included primary TKRs without patella resurfacing that were reported to the NAR during the years 1999-2012. To minimize the possible confounding effect of prosthesis brands, only brands that were used both as hybrids and cemented in more than 200 cases were included. Kaplan-Meier survival analysis and Cox regression analysis were done with adjustment for age, sex, and preoperative diagnosis. To include death as a competing risk, cumulative incidence function estimates were calculated. RESULTS: Estimated survival at 11 years was 94.3% (95% CI: 93.9-94.7) in the cemented TKR group and 96.3% (CI: 95.3-97.3) in the hybrid TKR group. The adjusted Cox regression analysis showed a lower risk of revision in the hybrid group (relative risk = 0.58, CI: 0.48-0.72, p < 0.001). The hybrid group included 3 brands of prostheses: LCS classic, LCS complete, and Profix. Profix hybrid TKR had lower risk of revision than cemented TKR, but the LCS classic and LCS complete did not. Kaplan-Meier estimated survival at 11 years was 96.8% (CI: 95.6-98.0) in the hybrid Profix group and 95.2% (CI: 94.6-95.8) in the cemented Profix group. Mean operating time was 17 min longer in the cemented group. INTERPRETATION: Survivorship of the hybrid TKR at 11 years was better than that for cemented TKR, or the same, depending on the brand of prosthesis. Hybrid fixation appears to be a safe and time-efficient alternative to cemented fixation in total knee replacement surgery.

Subjective Health Complaints Among Workers in the Aftermath of an Oil Tank Explosion.

The aim of the study was to assess whether exposed workers had more subjective health complaints than controls 1 1/2 years after a chemical explosion involving a mixture of hydrocarbons and sulfurous compounds. A cross-sectional survey based on the Subjective Health Complaints Inventory (SHC) was conducted among 147 exposed workers and 137 controls. A significantly higher total SCH score (linear regression, p=.01) was found for the exposed workers compared with controls when adjusting for gender, age, smoking habits, and educational level. The exposed workers reported significantly more headache, hot flashes, sleep problems, tiredness, dizziness, and sadness/depression. The cause of these complaints is unknown, but health personnel should be aware that health complaints might be related to polluting episodes even when exposure levels are below occupational guideline levels.

Airway symptoms and lung function among male workers in an area polluted from an oil tank explosion.

OBJECTIVE: To assess whether working in an industrial harbor where an oil tank exploded was associated with more airway symptoms and lower lung function in men 1.5 years later. METHODS: In a cross-sectional study of 180 men, 18 to 67 years old, airway symptoms and lung function among men who worked in the industrial harbor at the time of the explosion was compared with those of working men with residence more than 20 km away. Regression analyses are adjusted for smoking, occupational exposure, atopy, recent infection, and age. RESULTS: Exposed men had significantly more upper (ORirritated nose = 2.89 [95% confidence interval = 1.31 to 6.37]) and lower (ORdyspnea uphill = 3.79 [95% confidence interval = 1.69 to 8.46]) airway symptoms, and some indication of more reversible airway obstruction than unexposed workers. CONCLUSIONS: Men working in an area with an oil tank explosion had more airway symptoms and indication of more airway obstruction 1.5 years after the event.

Is the use of computer navigation in total knee arthroplasty improving implant positioning and function? A comparative study of 198 knees operated at a Norwegian district hospital.

BACKGROUND: There are few Scandinavian studies on the effect of computer assisted orthopedic surgery (CAOS) in total knee arthroplasty (TKA), compared to conventional technique (CON), and there is little information on effects in pain and function scores. This retrospective study has evaluated the effects of CAOS on radiological parameters and pain, function and quality of life after primary TKA. METHODS: 198 primary TKAs were operated by one surgeon in two district hospitals; 103 CAOS and 95 CON. The groups were evaluated based on 3 months post-operative radiographs and a questionnaire containing the knee osteoarthritis outcome score (KOOS), the EQ-5D index score and a visual analogue scale (VAS) two years after surgery. Multiple linear regression method was used to investigate possible impact from exposure (CON or CAOS). RESULTS: On hip-knee-ankle radiographs, 20% of measurements were > ±3° of neutral in the CAOS group and 25% in the CON group (p = 0.37). For the femoral component, the number was 5% for CAOS and 18% for CON (p < 0.01). For the tibial component, the difference was not statistically significant (p = 0.58). In the sagittal plane, the surgeon tended to apply more femoral flexion and more posterior tibial slope with CAOS. We observed no statistically or clinically significant difference in KOOS score, VAS or ∆EQ-5D (all p values >0.05), but there was a trend towards better scores for CAOS. Operation time was 3 minutes longer for CON (p = 0.37). CONCLUSIONS: CAOS can improve radiological measurements in primary TKA, and makes it possible to adjust component placement to the patient's anatomy. Over-all, the two methods are equal in pain, function and quality-of-life scores.

Failure of total knee arthroplasty with or without patella resurfacing.

BACKGROUND AND PURPOSE: Patella resurfacing during primary total knee arthroplasty (TKA) is disputed and new prosthesis designs have been introduced without documentation of their survival. We assessed the impact on prosthesis survival of patella resurfacing and of prosthesis brand, based on data from the Norwegian Arthroplasty Register. PATIENTS AND METHODS: 5 prosthesis brands in common use with and without patella resurfacing from 1994 through 2009 were included n = 11,887. The median follow-up times were 9 years for patella-resurfaced implants and 7 years for implants without patella resurfacing. For comparison of prosthesis brands, also brands in common use with only one of the two treatment options were included in the study population (n = 25,590). Cox regression analyses were performed with different reasons for revision as endpoints with adjustment for potential confounders. RESULTS: We observed a reduced overall risk of revision for patella resurfaced (PR) TKAs, but the statistical significance was borderline (RR = 0.84, p = 0.05). At 15 years, 92% of PR and 91% of patella non resurfaced (NR) prostheses were still unrevised. However, PR implants had a lower risk of revision due to pain alone (RR = 0.1, p < 0.001), but a higher risk of revision due to loosening of the tibial component (RR = 1.4, p = 0.03) and due to a defective polyethylene insert (RR = 3.2, p < 0.001). At 10 years, the survival for the reference NR brand AGC Universal was 93%. The NR brands Genesis I, Duracon, and Tricon (RR = 1.4-1.7) performed statistically significantly worse than NR AGC Universal, while the NR prostheses e.motion, Profix, and AGC Anatomic (RR = 0.1-0.7), and the PR prostheses NexGen and AGC Universal (RR = 0.4-0.5) performed statistically significantly better. LCS, NexGen, LCS Complete (all NR), and Tricon, Genesis I, LCS, and Kinemax (all PR) showed no differences in this respect from the reference brand. A lower risk of revision (crude) was found for TKAs performed after 2000 as compared to those performed earlier (RR = 0.8, p = 0.001). INTERPRETATION: Although revision risk was similar for PR and NR TKAs, we found important differences in reasons for revision. Our results also indicate that survivorship of TKAs has improved.

Pain and function in patients after primary unicompartmental and total knee arthroplasty.

BACKGROUND: Unicompartmental knee arthroplasty has received renewed interest; however, its short-term advantages over total knee arthroplasty should be weighed against a higher risk of reoperation. Information regarding pain and function after unicompartmental and total knee arthroplasty is therefore needed. METHODS: Patient-reported data regarding pain and function were collected, at least two years postoperatively and by way of postal questionnaire, from 1344 patients who were listed on the Norwegian Arthroplasty Register as having had an unrevised primary total knee arthroplasty (972 patients) or a unicompartmental knee arthroplasty (372 patients) for the treatment of arthritis. Outcomes were assessed (with a score of zero indicating the worst possible outcome and a score of 100 indicating the best possible outcome) with use of the five subscales from the Knee Injury and Osteoarthritis Outcome Score, the scores from visual analog scales regarding degree of pain and satisfaction with the surgery, and the change in index score (from preoperative to postoperative) on the EuroQol-5D health-related quality-of-life instrument. We also used all forty-two questions from the Knee Injury and Osteoarthritis Outcome Score as outcome measures. To be regarded as clinically significant, the differences needed to be eight units for the Knee Injury and Osteoarthritis Outcome Score outcomes, ten units for the pain and satisfaction scales, and 0.4 unit for the detailed Knee Injury and Osteoarthritis Outcome Score questions. RESULTS: Unicompartmental knee implants performed better than total knee implants on the Knee Injury and Osteoarthritis Outcome subscales for "Symptoms" (adjusted mean difference, 2.7; p = 0.04), "Function in Daily Living" (adjusted mean difference, 4.1; p = 0.01), and "Function in Sport and Recreation" (adjusted mean difference, 5.4; p = 0.006). Of the forty-two analyses of the detailed questions, four differences were significant. These differences were in favor of unicompartmental knee arthroplasty, but only the question "Can you bend your knee fully?" reached the level of clinical significance. CONCLUSIONS: We found only small or no differences in pain and function between the scores, at least two years following surgery, of patients who underwent unicompartmental knee arthroplasty and those of patients who underwent total knee arthroplasty; however, patients with unicompartmental knee implants had fewer problems with activities that involved bending the knee.

Does patella resurfacing really matter? Pain and function in 972 patients after primary total knee arthroplasty.

BACKGROUND AND PURPOSE: Resurfacing of the patella during primary total knee arthroplasty (TKA) is often recommended based on higher revision rates in non-resurfaced knees. As many of these revisions are insertions of a patella component due to pain, and since only patients with a non-resurfaced patella have the option of secondary resurfacing, we do not really know whether these patients have more pain and poorer function. The main purpose of the present paper was therefore to assess pain and function at least 2 years after surgery for unrevised primary non-resurfaced and resurfaced TKA, and secondary among prosthesis brands. METHODS: Information needed to calculate subscales from the knee injury and osteoarthritis outcome score (KOOS) was collected in a questionnaire given to 972 osteoarthritis patients with intact primary TKAs that had been reported to the Norwegian Arthroplasty Register. Pain and satisfaction on visual analog scales and improvement in EQ-5D index score DeltaEQ-5D) were also used as outcomes. Outcomes were measured on a scale from 0 to 100 units (worst to best). To estimate differences in mean scores, we used multiple linear regression with adjustment for possible confounders. RESULTS: We did not observe any differences between resurfacing and non-resurfacing in any outcome, with estimated differences of 0.4. There was, however, a tendency of better results for the NexGen implant as compared to the reference brand AGC for symptoms (difference = 4.9, p = 0.05), pain (VAS) (difference = 8.3, p = 0.004), and satisfaction (VAS) (difference = 7.9, p = 0.02). However, none of these differences reached the stated level of minimal perceptible clinical difference. INTERPRETATION: Resurfacing of the patella has no clinical effect on pain and function after TKA. Differences between the brands investigated were small and they were assumed to be of minor importance.