Short-term Revision Risk of Patellofemoral Arthroplasty Is High: An Analysis from Eight Large Arthroplasty Registries.

BACKGROUND: Patellofemoral arthroplasty (PFA) is one option for the treatment of isolated patellofemoral osteoarthritis, but there are limited data regarding the procedure and results. Because isolated patellofemoral arthritis is relatively uncommon, available case series generally are small, and even within national registries, sample sizes are limited. Combining data from multiple registries may aid in assessing worldwide PFA usage and survivorship. QUESTIONS/PURPOSES: We combined and compared data from multiple large arthroplasty registries worldwide to ask: (1) What proportion of patients undergoing primary knee arthroplasty have PFA? (2) What are the patient and prosthesis characteristics associated with PFA in common practice, as reflected in registries? (3) What is the survivorship free from revision of PFA and what are the reasons for and types of revisions? METHODS: Data were provided by eight registries that are members of the International Society of Arthroplasty Registries (ISAR) who agreed to share aggregate data: Australia, New Zealand, Canada, Sweden, Finland, Norway, the Netherlands, and the United States. De-identified data were obtained for PFA performed from either the beginning of year 2000, or the earliest recorded implantation date after that in each individual registry when PFA data collection commenced, up to December 31, 2016. This included patient demographics, implant use, all-cause revision rate (determined by cumulative percent revision [CPR]), and reasons for and type of revision. RESULTS: During the data collection period, 6784 PFAs were performed in the eight countries. PFAs comprised less than 1% of primary knee replacements in all registries. Patient demographics were comparable in all countries. Patients were generally more likely to be women than men, and the mean age ranged from 50 years to 60 years. All registries showed a high rate of revision for PFA. The 5-year CPR for any reason ranged from 8.0% (95% CI 4.5 to 11.5) in Norway to 18.1% (95% CI 15.5 to 20.7) in the Netherlands. The most common reason for revision across all countries was disease progression (42%, 434 of 1034). Most PFAs (83%, 810 of 980) were revised to a TKA. CONCLUSIONS: The revision risk of PFA in all registries surveyed was more than three times higher than the reported revision risk of TKA at the same times. The survivorship of PFA is similar to that of the no-longer-used procedure of metal-on-metal conventional hip replacement. Although there may be potential functional benefits from PFA, these findings of consistent and alarmingly high rates of revision should create concern, particularly as this procedure is often used in younger patients. LEVEL OF EVIDENCE: Level III, therapeutic study.

Editorial Commentary: Got Evidence? What We Really Need Is an Algorithm for Treating Symptomatic Bipartite Patella.

Bipartite patella is an uncommon but potentially troublesome problem for young athletes. Numerous uncontrolled retrospective studies have reported good results after various treatments. What is needed are studies that will guide workup and support treatment decisions based on the condition of the cartilage surfaces of the fragment, presence of pseudoarthrosis, and size and location of the fragment. To support decisions, we need prospective comparative studies, either randomized or, at least, prospective cohort studies that identify patients at the time of presentation, document key decision points, and follow patients to successful resolution of symptoms.

Injury pathology at the time of anterior cruciate ligament reconstruction associations with self-assessment of knee function.

OBJECTIVE: To evaluate the association of preoperative Knee Injury and Osteoarthritis Outcome Score (KOOS) and structural injuries reported at the time of anterior cruciate ligament reconstruction (ACLR). DESIGN: Cross-sectional study. SETTING: Three medical centers in California. PARTICIPANTS: Primary ACLRs (N = 636) performed between January 2009 and June 2010. INDEPENDENT VARIABLES: The 5 KOOS subscales: pain, other symptoms, activities of daily living (ADL), function in sport and recreation (Sport/Rec), and quality of life (QoL). MAIN OUTCOME MEASURES: Associated injuries (cartilage, medial meniscus, lateral meniscus, other ligaments), identified at the time of ACLR. RESULTS: Sixty-eight percent of the cohort was male and the median age was 26 years. No gender differences in KOOS were observed. No KOOS differences were observed by race, except in Sport/Rec. Younger patients reported higher KOOS. Pain and ADL scores were not associated with any concurrent injury. A 10-point increase in KOOS symptoms subscale was associated with 22% higher likelihood of isolated ACL, 13% lower likelihood of medial meniscus injury, and 10% lower likelihood of lateral meniscus. A 10-point increase in the KOOS Sport/Rec subscale score was associated with 8% higher likelihood of isolated ACL and 9% lower likelihood of medial meniscus injury. A 10-point increase in the KOOS QoL subscale was associated with 15% lower likelihood of medial meniscus injury. CONCLUSIONS: Weak associations between the symptoms, Sports/Rec, and QoL subscales and structural injuries at ACLR were observed. The KOOS and its subscales are not useful as indicators of the pattern or severity of preoperative injury of patients presenting for ACLR.

Patellofemoral joint: from instability to arthritis.

Disorders of the patellofemoral joint are commonly seen in musculoskeletal clinics. In recent years, the expansion of imaging techniques, improvements in correlative injury anatomy, and more focused physical examinations have resulted in new knowledge about patellofemoral disorders. To achieve optimal patient outcomes, it is helpful for orthopaedic surgeons who treat knee problems to review the management of patellar dislocations and isolated patellofemoral arthritis, including treatment algorithms.

The impact of pre-operative weight loss on incidence of surgical site infection and readmission rates after total joint arthroplasty.

This study characterized a cohort of obese total hip arthroplasty (THA) and total knee arthroplasty (TKA) patients (1/1/2008-12/31/2010) and evaluated whether a clinically significant amount of pre-operative weight loss (5% decrease in body weight) is associated with a decreased risk of surgical site infections (SSI) and readmissions post-surgery. 10,718 TKAs and 4066 THAs were identified. During the one year pre-TKA 7.6% of patients gained weight, 12.4% lost weight, and 79.9% remained the same. In the one year pre-THA, 6.3% of patients gained weight, 18.0% lost weight, and 75.7% remained the same. In TKAs and THAs, after adjusting for covariates, the risk of SSI and readmission was not significantly different in the patients who gained or lost weight pre-operatively compared to those who remained the same.

Medial patellofemoral ligament (MPFL) reconstruction for the treatment of patellofemoral instability.

Patellofemoral instability can be a disabling problem. Numerous techniques are employed for its treatment. Medial patellofemoral ligament (MPFL) reconstruction in combination with other procedures has been explored by many orthopedic surgeons. The purpose of the study was to determine the effectiveness of isolated MPFL reconstruction in treating the symptoms associated with patellofemoral instability, preventing recurrence of patella dislocation, and returning patients to preinjury level of activity. This is a case series study. We conducted a clinical follow-up study on 56 knees (49 patients) after MPFL reconstruction for recurrent patellar instability with a mean follow-up of 4.3 years (range, 1.1-6.8). A single MPFL reconstruction technique was performed in all cases. Patient outcomes were evaluated using: International Knee Documentation Committee (IKDC) subjective knee form, Tegner activity score, functional hop test, and radiographs. Mean age at time of surgery was 24 years old (range, 13-49). Females comprised 75% of the sample. Mean interval from injury to surgery was 7.2 ± 8.6 years (range, 51 days-37 years). At follow-up, there were no recurrent dislocations reported, patella subluxation in 6 (11%) cases, and radiographic degenerative changes were none to mild in all patients. The series mean IKDC scores at follow-up was 76.3 ± 19.2 (range, 30-99), and Tegner activity scores were 5.6 ± 2.5. MPFL reconstruction is an option for treating the symptoms of patellar instability, preventing recurrent dislocation, and returning patients near to their preinjury level of activity. The level of evidence is IV.

Do patients lose weight after joint arthroplasty surgery? A systematic review.

BACKGROUND: The ability of patients with a total joint arthroplasty (TJA) to lose weight after surgery has been investigated in a few studies with inconsistent results. QUESTIONS/PURPOSES: We asked: (1) What is the quality of evidence of current published literature on postoperative weight trends for patients who have had a TJA? (2) Do patients lose any weight after TJA? (3) Do patients lose a clinically meaningful amount of weight after TJA? METHODS: We conducted a systematic review of PubMed and the Cochrane Library. Studies were summarized according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses Statement. Studies were reviewed for quality of evidence and limitations according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria. Twelve studies were identified, one case-cohort study and 11 case series. Most studies were from single-surgeon or single-hospital series. Five studies included THAs and TKAs, four only THAs, and three only TKAs. We determined study type, level of evidence, inclusion criteria, procedures, proportion of patients who changed weight, body composition assessment, time of composition assessment, statistical analysis performed, and subgroup analysis conducted. RESULTS: Owing to the observational nature of the studies and the serious limitations identified, all were considered very low quality according to GRADE criteria. Studies reported 14% to 49% of patients had some weight loss at least 1 year postoperatively. CONCLUSIONS: We found no conclusive evidence that weight or body composition increases, decreases, or remains the same after TJA.

Transcriptional time course after rotator cuff repair in 6 month old female rabbits.

Introduction: Rotator cuff tears are prevalent in the population above the age of 60. The disease progression leads to muscle atrophy, fibrosis, and fatty infiltration, which is not improved upon with surgical repair, highlighting the need to better understand the underlying biology impairing more favorable outcomes. Methods: In this study, we collected supraspinatus muscle tissue from 6 month old female rabbits who had undergone unilateral tenotomy for 8 weeks at 1, 2, 4, or 8 weeks post-repair (n = 4/group). RNA sequencing and enrichment analyses were performed to identify a transcriptional timeline of rotator cuff muscle adaptations and related morphological sequelae. Results: There were differentially expressed (DE) genes at 1 (819 up/210 down), 2 (776/120), and 4 (63/27) weeks post-repair, with none at 8 week post-repair. Of the time points with DE genes, there were 1092 unique DE genes and 442 shared genes, highlighting that there are changing processes in the muscle at each time point. Broadly, 1-week post-repair differentially expressed genes were significantly enriched in pathways of metabolism and energetic activity, binding, and regulation. Many were also significantly enriched at 2 weeks, with the addition of NIF/NF-kappaB signaling, transcription in response to hypoxia, and mRNA stability alongside many additional pathways. There was also a shift in transcriptional activity at 4 weeks post-repair with significantly enriched pathways for lipids, hormones, apoptosis, and cytokine activity, despite an overall decrease in the number of differentially expressed genes. At 8 weeks post-repair there were no DE genes when compared to control. These transcriptional profiles were correlated with the histological findings of increased fat, degeneration, and fibrosis. Specifically, correlated gene sets were enriched for fatty acid metabolism, TGF-B-related, and other pathways. Discussion: This study identifies the timeline of transcriptional changes in muscle after RC repair, which by itself, does not induce a growth/regenerative response as desired. Instead, it is predominately related to metabolism/energetics changes at 1 week post-repair, unclear or asynchronous transcriptional diversity at 2 weeks post-repair, increased adipogenesis at 4 weeks post-repair, and a low transcriptional steady state or a dysregulated stress response at 8 weeks post-repair.

The "Second Hit" of Repair in a Rabbit Model of Chronic Rotator Cuff Tear.

The rabbit supraspinatus is a useful translational model for rotator cuff (RC) repair because it recapitulates muscle atrophy and fat accumulation observed in humans after a chronic tear (the "first hit"). However, a timeline of RC tissue response after repair, especially with regard to recent evidence of muscle degeneration and lack of regeneration, is currently unavailable. Thus, the purpose of this study was to characterize the progression of muscle and fat changes over time after the repair of a chronic RC tear in the rabbit model. Two rounds of experiments were conducted in 2017-2018 and 2019-2020 with N = 18 and 16 skeletally mature New Zealand White rabbits, respectively. Animals underwent left supraspinatus tenotomy with repair 8 weeks later. The unoperated right shoulder served as control. The rabbits were sacrificed at 1-, 2-, 4-, and 8-weeks post-repair for histological and biochemical analysis. Atrophy, measured by fiber cross-sectional area and muscle mass, was greatest around 2 weeks after repair. Active muscle degeneration peaked at the same time, involving 8% of slide areas. There was no significant regeneration at any timepoint. Fat accumulation and fibrosis were significantly increased across all time points compared to contralateral. Statement of Clinical Significance: These results demonstrate model reproducibility and a "second hit" phenomenon of repair-induced muscle atrophy and degeneration which partially recovers after a short time, while increased fat and fibrosis persist.

Supraspinatus muscle architecture and physiology in a rabbit model of tenotomy and repair.

Chronic rotator cuff tears can cause severe functional deficits. Addressing the chronic fatty and fibrotic muscle changes is of high clinical interest; however, the architectural and physiological consequences of chronic tear and repair are poorly characterized. We present a detailed architectural and physiological analysis of chronic tear and repair (both over 8 and 16 wk) compared with age-matched control rabbit supraspinatus (SSP) muscles. Using female New Zealand White Rabbits (n = 30, n = 6/group) under 2% isoflurane anesthesia, the SSP was surgically isolated and maximum isometric force was measured at four to six muscle lengths. Architectural analysis was performed, and maximum isometric stress was computed. Whole muscle length-tension curves were generated using architectural measurements to compare experimental physiology to theoretical predictions. Architectural measures are consistent with persistent radial and longitudinal atrophy over time in tenotomy that fails to recover after repair. Maximum isometric force was significantly decreased after 16 wk tenotomy and not significantly improved after repair. Peak isometric force reported here are greater than prior reports of rabbit SSP force after tenotomy. Peak stress was not significantly different between groups and consistent with prior literature of SSP stress. Muscle strain during contraction was significantly decreased after 8 wk of tenotomy and repair, indicating effects of tear and repair on muscle function. The experimental length-tension data were overlaid with predicted curves for each experimental group (generated from structural data), exposing the altered structure-function relationship for tenotomy and repair over time. Data presented here contribute to understanding the physiological implications of disease and repair in the rotator cuff.NEW & NOTEWORTHY We utilize an established method to measure the length-tension relationship for the rabbit supraspinatus in normal, torn, and repaired muscles. We then perform architectural analysis to evaluate structural changes after tear and repair. Although peak isometric force is lower in the tear and repair groups, there are no differences in peak stresses across groups. These findings indicate persistent structural changes (both radial and longitudinal atrophy) and physiological deficiencies (decreased peak force and uncoupling structure-function relationship) after tenotomy that do not significantly recover after repair.

Corrigendum: Transcriptional Time Course After Rotator Cuff Tear.

[This corrects the article DOI: 10.3389/fphys.2021.707116.].

Transcriptional Time Course After Rotator Cuff Tear.

Rotator cuff (RC) tears are prevalent in the population above the age of 60. The disease progression leads to muscle atrophy, fibrosis, and fatty infiltration in the chronic state, which is not improved with intervention or surgical repair. This highlights the need to better understand the underlying dysfunction in muscle after RC tendon tear. Contemporary studies aimed at understanding muscle pathobiology after RC tear have considered transcriptional data in mice, rats and sheep models at 2-3 time points (1 to 16 weeks post injury). However, none of these studies observed a transition or resurgence of gene expression after the initial acute time points. In this study, we collected rabbit supraspinatus muscle tissue with high temporal resolution (1, 2, 4, 8, and 16 weeks) post-tenotomy (n = 6/group), to determine if unique, time-dependent transcriptional changes occur. RNA sequencing and analyses were performed to identify a transcriptional timeline of RC muscle changes and related morphological sequelae. At 1-week post-tenotomy, the greatest number of differentially expressed genes was observed (1,069 up/873 down) which decreases through 2 (170/133), 4 (86/41), and 8 weeks (16/18), followed by a resurgence and transition of expression at 16 weeks (1,421/293), a behavior which previously has not been captured or reported. Broadly, 1-week post-tenotomy is an acute time point with expected immune system responses, catabolism, and changes in energy metabolism, which continues into 2 weeks with less intensity and greater contribution from mitochondrial effects. Expression shifts at 4 weeks post-tenotomy to fatty acid oxidation, lipolysis, and general upregulation of adipogenesis related genes. The effects of previous weeks' transcriptional dysfunction present themselves at 8 weeks post-tenotomy with enriched DNA damage binding, aggresome activity, extracellular matrix-receptor changes, and significant expression of genes known to induce apoptosis. At 16 weeks post-tenotomy, there is a range of enriched pathways including extracellular matrix constituent binding, mitophagy, neuronal activity, immune response, and more, highlighting the chaotic nature of this time point and possibility of a chronic classification. Transcriptional activity correlated significantly with histological changes and were enriched for biologically relevant pathways such as lipid metabolism. These data provide platform for understanding the biological mechanisms of chronic muscle degeneration after RC tears.

Does discharge disposition after primary total joint arthroplasty affect readmission rates?

We reviewed 90-day readmission rates for 9150 patients with a primary total hip or knee arthroplasty performed between April 2001 and December 2004. Patients with an American Society of Anesthesiologists score of 3 or greater or with perioperative complications were excluded. We correlated the readmission rate with discharge disposition to either skilled nursing facilities (SNFs) or Home. Of the 9150 patients identified, 1447 were discharged to an SNF. After statistically adjusting for sex, age and American Society of Anesthesiologists scores, total hip arthroplasty and total knee arthroplasty patients discharged to SNFs had higher odds of hospital readmission within 90 days of surgery than those discharged home (total hip arthroplasty: odds ratio = 1.9; 95% confidence interval, 1.2-3.2; P = .008; total knee arthroplasty: odds ratio = 1.6; 95% confidence interval, 1.1-2.4; P = .01). Healthy patients discharged to SNFs after primary total joint arthroplasty need to be followed closely for complications.

Does the use of fluoroscopy and isometry during anterior cruciate ligament reconstruction affect surgical decision making?

OBJECTIVE: Poor results after anterior cruciate ligament (ACL) reconstruction are often due to inaccurate graft placement. Numerous strategies have been advocated to improve accuracy and consistency of tunnel positioning, including computer-assisted navigation. Less expensive alternatives, such as intraoperative fluoroscopy and isometry, have also been advocated for confirming guide pin placement before reaming the femoral tunnel. It is unknown how often these techniques cause surgeons to change the location of their femoral tunnel at the time of surgery. We undertook this study to determine how often this approach results in repositioning of the guide pin before final graft placement. We hypothesized that a lower level of surgeon experience would lead to a higher frequency of repositioning compared to a higher level of experience. DESIGN: Prospective, case series. SETTING: Institutional. PATIENTS: Intraoperative data were gathered prospectively from 413 consecutive, primary ACL reconstructions performed by the sports medicine group at our institution. Of the 413 procedures enrolled in this study, 407 were available for analysis. Six procedures were excluded because the tension isometer was unavailable during the procedure. INTERVENTIONS: Isometry and fluoroscopy were used in all cases to aid in the accurate placement of the femoral tunnel. Femoral pin change based on the results of isometry or fluoroscopy was recorded. The percentage of cases involving a change in the femoral pin resulting from the use of these techniques was calculated. This percentage was also calculated separately for cases performed by a staff surgeon (fellowship-trained sports medicine staff) as well as less experienced surgeons (current sports medicine fellows). MAIN OUTCOME MEASURES: The main outcome measurement was whether the femoral pin was changed. RESULTS: Of the 407 procedures available for review, 62 (15%) of them involved a change in femoral pin position secondary to information provided by intraoperative isometry or fluoroscopy. In the procedures performed by more experienced surgeons, the pin was changed in 40 (16%) of 253 cases; in those performed by less experienced surgeons, it was changed in 22 (14%) of 154 cases. CONCLUSIONS: The intraoperative use of isometry and fluoroscopy during ACL reconstruction led to changes in the femoral tunnel placement 15% of the time. The influence of these instruments on intraoperative decision making does not seem to diminish with surgical experience.

Outcomes of routine use of antibiotic-loaded cement in primary total knee arthroplasty.

The routine use of antibiotic-loaded bone cement (ALBC) in primary total knee arthroplasty (TKA) is controversial. Outcomes were recorded in patients who underwent primary TKA from May 2003 to March 2007 using a community-based total joint registry. Infection rates were compared in patients undergoing TKA with ALBC and regular cement. A total of 22 889 primary TKA were performed, with 2030 cases (8.9%) using ALBC. Two thousand four hundred forty-nine patients were diabetic (10.7%), with ALBC used in 295 cases (12%). The rate of deep infection was 1.4% for ALBC TKA (28 cases) and 0.7% (154 cases) with regular cement (P = .002). Among patients with diabetes, the infection rate was 1.7% (5 cases) with ALBC and 0.9% (19 cases) with regular cement (P = .199). In patients whom surgeons considered higher risk for infection, ALBC did not appear to reduce TKA infection rates. The routine use of antibiotic-laden cement warrants further investigation.

Knee replacement: epidemiology, outcomes, and trends in Southern California: 17,080 replacements from 1995 through 2004.

BACKGROUND AND PURPOSE: There are limited population-based data on utilization, outcomes, and trends in total knee arthroplasty (TKA). The purpose of this study was to examine TKA utilization and short-term outcomes in a pre-paid health maintenance organization (HMO), and to determine whether rates and revision burden changed over time. We also studied whether this population is representative of the general population in California and in the United States. METHODS: Using hospital utilization and membership databases from 1995 through 2004, we calculated incidence rates (IRs) of primary and revision TKA for every 10,000 health plan members. The demographics of the HMO population were compared to published census data from California and the United States. RESULTS: The age and sex distributions of the study population were similar to those of the general population in California and the United States. 15,943 primary TKAs and 1,137 revision TKAs were performed during the 10-year period. Patients below the age of 65 accounted for one-third of all primary replacements and one-third of all revision replacements. IRs of primary TKAs increased from 6.3 per 10,000 in 1995 to 11.0 per 10,000 in 2004, at a rate of 5% per year (p<0.001). IRs of revision TKAs increased from 0.41 per 10,000 in 1995 to 0.74 per 10,000 in 2004 (p=0.4). Revision burden remained stable over the 10-year observation period. Surgical complications were higher in revision TKA than in primary TKA (10% vs. 7.7%; p=0.007). 90 day complication rates for primary and revision TKA including death were 0.3% and 0.6% (p=0.1) and for pulmonary embolism 0.5% and 0.4% (p=0.6). 90 day re-admission rates for primary and revision TKA including infection were 0.5% and 4.2% (p<0.001), for myocardial infarction 0.1% each, and for pneumonia 0.2% and 0.4% (p=0.08). INTERPRETATION: The incidence of primary and revision TKA increased between 1995 and 2005. The rates of postoperative complications were low. Comparisons of the study population and the underlying general populations of interest indicate that this population can be used to predict the incidences and outcomes of TKA in the general population of California and of the United States as a whole.

National Athletic Trainers' Association Position Statement: Management of Individuals With Patellofemoral Pain.

OBJECTIVE:: To present recommendations for athletic trainers and other health care providers regarding the identification of risk factors for and management of individuals with patellofemoral pain (PFP). BACKGROUND:: Patellofemoral pain is one of the most common knee diagnoses; however, this condition continues to be one of the most challenging to manage. Recent evidence has suggested that certain risk factors may contribute to the development of PFP. Early identification of risk factors may allow clinicians to develop and implement programs aimed at reducing the incidence of this condition. To date, clinicians have used various treatment strategies that have not necessarily benefitted all patients. Suboptimal outcomes may reflect the need to integrate clinical practice with scientific evidence to facilitate clinical decision making. RECOMMENDATIONS:: The recommendations are based on the best available evidence. They are intended to give athletic trainers and other health care professionals a framework for identifying risk factors for and managing patients with PFP.

Reliability of the international knee documentation committee radiographic grading system.

BACKGROUND: The International Knee Documentation Committee (IKDC) forms are commonly used to measure outcomes after anterior cruciate ligament (ACL) reconstruction. The knee examination portion of the IKDC forms includes a radiographic grading system to grade degenerative changes. The interrater and intrarater reliability of this radiographic grading system remain unknown. HYPOTHESIS: We hypothesize that the IKDC radiographic grading system will have acceptable interrater and intrarater reliability. STUDY DESIGN: Case series (diagnosis); Level of evidence, 4. METHODS: Radiographs of 205 ACL-reconstructed knees were obtained at 5-year follow-up. Specifically, weightbearing posteroanterior radiographs of the operative knee in 35 degrees to 45 degrees of flexion and a lateral radiograph in 30 degrees of flexion were used. The radiographs were independently graded by 2 sports medicine fellowship-trained orthopaedic surgeons using the IKDC 2000 standard instructions. One surgeon graded the same radiographs 6 months apart, blinded to patient and prior IKDC grades. The percentage agreement was calculated for each of the 5 knee compartments as defined by the IKDC. Interrater reliability was evaluated using the intraclass correlation coefficient (ICC) 2-way mixed effect model with absolute agreement. The Spearman rank-order correlation coefficient (r(s)) was applied to evaluate intrarater reliability. RESULTS: The interrater agreement between the 2 surgeons was 59% for the medial joint space (ICC = 0.46; 95% confidence interval [CI] = 0.35-0.56), 54% for the lateral joint space (ICC = 0.45; 95% CI = 0.27-0.58), 49% for the patellofemoral joint (ICC = 0.40; 95% CI = 0.26-0.52), 63% for the anterior joint space (ICC = 0.20; 95% CI = 0.05-0.34), and 44% for the posterior joint space (ICC = 0.28; 95% CI = 0.15-0.40). The intrarater agreement was 83% for the medial joint space (r(s) = .77, P < .001), 86% for the lateral joint space (r(s) = .76, P < .001), 81% for the patellofemoral joint (r(s) = .79, P < .001), 91% for the anterior joint space (r(s) = .48, P < .001), and 69% for the posterior joint space (r(s) = .64, P < .001). CONCLUSIONS: While intrarater reliability was acceptable, interrater reliability was poor. These findings suggest that multiple raters may score the same radiographs differently using the IKDC radiographic grading system. The use of a single rater to grade all radiographs when using the IKDC radiographic grading system maximizes reliability.

Effect of body mass index on patient outcomes of surgical intervention for the lumbar spine.

BACKGROUND: Conflicting findings exist on the effect of obesity on outcomes of lumbar spine surgery; results depend on the diagnosis studied, procedure evaluated, definition of obesity, and specific outcomes measured. The purpose of this retrospective cohort study is to examine the effect of increasing body mass index (BMI) on surgical-related, health-related, and long-term outcomes of lumbar spine surgery in a single representative patient sample. METHODS: Using a surgical registry from an integrated health care system, 8,049 instrumented lumbar spine cases were identified between 1/1/2009 and 09/30/2013. The sample was stratified into five BMI categories. Outcomes of interest included: (I) surgical-related factors and complications; (II) health-related complications; and (III) long-term complications. Mixed linear models, conditional logistic regressions, and survival analysis using a Cox regression model were conducted controlling for surgeon effects. Age, gender, diabetes status, smoking status, admitting diagnosis, and surgical approach were included as covariates. RESULTS: Every 5 kg/m2 increase in BMI was associated with a significant increase in surgical time (7.8 minutes), estimated blood loss (EBL) (36.5 mL), risk of deep infection (OR =1.7 times), and deep vein thrombosis (DVT) (OR =1.5). BMI was not associated with increased incidence of other intraoperative or health-related complications. Rate of re-operation was 1.1 times higher with every 5 kg/m2 increase in BMI, but rate of re-operation due to adjacent segment disease (ASD) was not associated with BMI. CONCLUSIONS: Obesity had an adverse effect on certain surgical-related, health-related and long-term surgical outcomes. The magnitude of this effect increased with increasing levels of obesity, which increases the medical burden associated with obesity.

Anatomical posterior cruciate ligament transplantation: a biomechanical analysis.

BACKGROUND: Although current techniques of posterior cruciate ligament reconstruction may successfully stabilize the posterior cruciate ligament-deficient knee, no studies have demonstrated restoration of intact-knee kinematics. HYPOTHESIS: Posterior cruciate ligament transplantation will successfully restore posterior stability and kinematics to the posterior cruciate ligament-deficient knee. STUDY DESIGN: Controlled laboratory study. METHODS: Seven pairs (donor/recipient) of size-matched cadaveric knees underwent a novel technique for posterior cruciate ligament transplantation. The grafts were fixed at the femoral origin and tibial insertion using an inlay technique with rigid fixation. The knees were tested in the intact (intact group), posterior cruciate ligament-deficient (deficient group), and posterior cruciate ligament-transplanted (transplant group) states. A 3-dimensional electromagnetic tracking system during an active knee extension and passive knee flexion maneuver was used to quantify kinematics, specifically looking at femoral rollback. KT ligament arthrometry was used to quantify posterior stability at the quadriceps neutral angle (70 degrees ). RESULTS: For femoral rollback, the intact versus deficient groups was significantly different (P = .045) as was deficient versus transplant groups (P = .008) but not intact versus transplant groups. Similar differences were noted with the measurements of posterior stability (P < .001). Total posterior laxity between the intact versus deficient groups was significantly different (means, 1.32 mm vs 11.1 mm; P < .0001), as was deficient versus transplant groups (means, 11.1 mm vs 2.04 mm; P < .126) but not intact versus transplant groups. CONCLUSION: In a posterior cruciate ligament-deficient cadaveric model, we demonstrated the technical feasibility and efficacy of posterior cruciate ligament transplantation for restoring femoral rollback and posterior stability at the quadriceps neutral angle. CLINICAL RELEVANCE: Future studies in posterior cruciate ligament reconstruction should not only address stability but also restoration of normal knee kinematics in assessing the success of a given technique.