The Otto Aufranc Award: Does Hip Arthroscopy at the Time of Periacetabular Osteotomy Improve the Clinical Outcome for the Treatment of Hip Dysplasia? A Multi-Center Randomized Clinical Trial

BACKGROUND

A periacetabular osteotomy (PAO) is often sufficient to treat the symptoms and improve quality of life for symptomatic hip dysplasia. However, acetabular cartilage and labral pathologies are very commonly present, and there is a lack of evidence examining the benefits of adjunct arthroscopy to treat these. The goal of this study was to compare the clinical outcome of patients undergoing PAO with and without arthroscopy, with the primary endpoint being the International Hip Outcome Tool-33 (iHOT-33) at one year.

METHODS

In a multi-center study, two hundred and three patients who had symptomatic hip dysplasia were randomized: 97 patients undergoing an isolated PAO (mean age 27 years (range, 16 to 44); mean Body Mass Index (BMI) of 25.1 (range, 18.3 to 37.2); 86% women) and 91 patients undergoing PAO who had an arthroscopy [mean age 27 years (range, 16 to 49); mean BMI of 25.1 (17.5 to 25.1); 90% women].

RESULTS

At a mean follow up of 2.3 years (range, 1 to 5), all patients exhibited significant improvements in their functional score, with no significant differences between PAO plus arthroscopy versus PAO alone at 12 months post-surgery on all scores: pre-operative iHot-33 score of 31.2 (SD [standard deviation] 16.0) versus 36.4 (SD 15.9), and 12 months post-operative score of 72.4 (SD 23.4) versus 73.7 (SD 22.6)]. The pre-operative Hip disability and Osteoarthritis Outcome (HOOS)-pain score was 60.3 (SD 19.6) versus 66.1 (SD 20.0)] and 12 months post-operative [88.2 (SD 15.8) versus 88.4 (SD 18.3)]. The mean pre-operative physical health Patient-Reported Outcomes Measurement Information System (PROMIS) score was 42.5 (SD 8.0) versus 44.2 (SD 8.8) and 12 months post-operative [48.7 (SD 8.5) versus 52.0 (SD 10.6)]. There were four patients with PAO without arthroscopy who required an arthroscopy later to resolve persistent symptoms, and one patient from the PAO plus arthroscopy group required an additional arthroscopy.

CONCLUSION

This Randomized Controlled Trial (RCT) has failed to show any significant clinical benefit in performing hip arthroscopy at the time of the PAO at one-year follow-up. Longer follow-up will be required to determine if hip arthroscopy provides added value to a PAO for symptomatic hip dysplasia.

Decisional regret following corrective adult spinal deformity surgery: a single institution study of incidence and risk factors

PURPOSE

To assess the characteristics and risk factors for decisional regret following corrective adult spinal deformity (ASD) surgery at our hospital.

METHODS

This is a retrospective cohort study of a single-surgeon ASD database. Adult patients (> 40 years) who underwent ASD surgery from May 2016 to December 2020 with minimum 2-year follow-up were included (posterior-only, ≥ 4 levels fused to the pelvis) (n = 120). Ottawa decision regret questionnaires, a validated and reliable 5-item Likert scale, were sent to patients postoperatively. Regret scores were defined as (1) low regret: 0-39 (2) medium to high regret: 40-100. Risk factors for medium or high decisional regret were identified using multivariate models.

RESULTS

Ninety patients were successfully contacted and 77 patients consented to participate. Nonparticipants were older, had a higher incidence of anxiety, and higher ASA class. There were 7 patients that reported medium or high decisional regret (9%). Ninety percentage of patients believed that surgery was the right decision, 86% believed that surgery was a wise choice, and 87% would do it again. 8% of patients regretted the surgery and 14% believed that surgery did them harm. 88% of patients felt better after surgery. On multivariate analysis, revision fusion surgery was independently associated with an increased risk of medium or high decisional regret (adjusted odds ratio: 6.000, 95% confidence interval: 1.074-33.534, p = 0.041).

CONCLUSIONS

At our institution, we found a 9% incidence of decisional regret. Revision fusion was associated with increased decisional regret. Estimates for decisional regret should be based on single-institution experiences given differences in patient populations.

Comparison of Joint Mobilization and Movement Pattern Training for Patients With Hip-Related Groin Pain: A Pilot Randomized Clinical Trial

OBJECTIVE

The objective of this study was to assess the feasibility of completing a randomized clinical trial (RCT) and examine the preliminary effects of 2 interventions for hip-related groin pain (HRGP).

METHODS

In this pilot RCT, patients with HRGP, who were 18 to 40 years old, were randomized (1:1 ratio) to a joint mobilization (JtMob) group or a movement pattern training (MoveTrain) group. Both treatments included 10 supervised sessions and a home exercise program. The goal of JtMob was to reduce pain and improve mobility through peripherally and centrally mediated pain mechanisms. The key element was physical therapist-provided JtMob. The goal of MoveTrain was to reduce hip joint stresses by optimizing the biomechanics of patient-specific tasks. The key element was task-specific instruction to correct abnormal movement patterns displayed during tasks. Primary outcomes were related to future trial feasibility. The primary effectiveness outcome was the Hip Disability and Osteoarthritis Outcome Score. Examiners were blinded to group; patients and treatment providers were not. Data collected at baseline and immediately after treatment were analyzed with analysis of covariance using a generalized linear model in which change was the dependent variable and baseline was the covariate. The study was modified due to the coronavirus disease 2019 (COVID-19) pandemic.

RESULTS

The COVID-19 pandemic affected participation; 127 patients were screened, 33 were randomized (18 to the JtMob group and 15 to the MoveTrain group), and 29 (88%) provided posttreatment data. Treatment session adherence was 85%, and home exercise program component adherence ranged from 71 to 86%. Both groups demonstrated significant mean within-group improvements of ≥5 points on Hip Disability and Osteoarthritis Outcome Score scales. There were no between-group differences in effectiveness outcomes.

CONCLUSIONS

A large RCT to assess the effects of JtMob and MoveTrain for patients with HRGP may be feasible. Preliminary findings suggested that JtMob or MoveTrain may result in improvements in patient-reported pain and activity limitations.

IMPACT

The COVID-19 pandemic interfered with participation, but a randomized controlled trial may be feasible. Modification may be needed if the trial is completed during future pandemics.

Is Retention of the Acetabular Component at Revision Surgery a Long-Term Solution?

Background

Acetabular retention in revision total hip arthroplasty (THA) may be advantageous, yet long-term survival data is limited. Thus, we investigated long-term survivorship of retained acetabular components in revision THA with analysis of rerevision rate, instability risk, and clinical outcomes.

Methods

We reviewed 98 hips with polyethylene wear and/or osteolysis that were revised with retained acetabular components. Acetabular inclination and anteversion were measured from prerevision radiographs. A retrospective chart review was performed, collecting outcomes of interest including Harris hip score, instability events, and rerevision surgery. Kaplan-Meier analysis was used to calculate the risk of revision over time. Predictors of survival including acetabular component position were analyzed by multiple logistic regression.

Results

Average follow-up was 13 years (range, 5-24). Survivorship rates at 5, 10, 15, and 20 years were 89.7%, 81.6%, 70.8%, and 63.8%, respectively. There was improvement in average Harris hip score (61 to 76, P < .0001). There was a 9% rate of dislocation, and 6 hips (6%) were rerevised for recurrent instability. Overall, there were 23 (23%) rerevisions at an average of 6.1 years with the most common reasons being instability (6%) and aseptic loosening (6%). Use of conventional polyethylene was the only identified independent predictor of rerevision (P = .025).

Conclusions

Retention of a well-fixed acetabular component in revision THA provides acceptable long-term outcomes with a 15-year survivorship of 71%. Instability and aseptic loosening were the most common reasons for rerevision. Surgeons may consider retaining the acetabular component at revision surgery if the implant is well-fixed and well-positioned.

Why Didn't You Walk Yesterday? Factors Associated With Slow Early Recovery After Adult Spinal Deformity Surgery

STUDY DESIGN

This is a retrospective case-control study.

OBJECTIVES

The objectives of this study are to identify (1) risk factors for delayed ambulation following adult spinal deformity (ASD) surgery and (2) complications associated with delayed ambulation.

METHODS

One-hundred and ninety-one patients with ASD who underwent posterior-only fusion (≥5 levels, LIV pelvis) were reviewed. Patients who ambulated with physical therapy (PT) on POD2 or later (LateAmb, n = 49) were propensity matched 1:1 to patients who ambulated on POD0-1 (NmlAmb, n = 49) based on the extent of fusion and surgical invasiveness score (ASD-S). Risk factors, as well as inpatient medical complications were compared. Logistic regressions were used to identify risk factors for late ambulation.

RESULTS

Of the patients who did not ambulate on POD0-1, 32% declined participation secondary to pain or dizziness/fatigue, while 68% were restricted from participation by PT/nursing due to fatigue, inability to follow commands, nausea/dizziness, pain, or hypotension. Logistic regression showed that intraoperative estimated blood loss (EBL) >2L (OR = 5.57 [1.51-20.55], P = .010) was independently associated with an increased risk of delayed ambulation, with a 1.25 times higher risk for every 250 mL increase in EBL (P = .014). Modified 5-Item Frailty Index (mFI-5) was also independently associated with delayed ambulation (OR = 2.53 [1.14-5.63], P = .023). LateAmb demonstrated a higher hospital LOS (8.4 ± 4.0 vs 6.2 ± 2.6, P < .001). The LateAmb group trended toward an increase in medical complications on POD3+ (14.3% vs 26.5%, P = .210).

CONCLUSIONS

EBL demonstrates a dose-response relationship with risk for delayed ambulation. Delayed ambulation increases LOS and may impact medical complications.

Periacetabular osteotomy with or without arthroscopic management in patients with hip dysplasia: study protocol for a multicenter randomized controlled trial

Background

Hip dysplasia is one of the most common causes of hip arthritis. Its incidence is estimated to be between 3.6 and 12.8% (Canadian Institute for Health Information, Hip and knee replacements in Canada, 2017–2018: Canadian joint replacement registry annual report, 2019; Jacobsen and Sonne-Holm, Rheumatology 44:211–8, 2004). The Periacetabular Osteotomy (PAO) has been used successfully for over 30 years (Gosvig et al., J Bone Joint Surg Am 92:1162–9, 2010), but some patients continue to exhibit symptoms post-surgery (Wyles et al., Clin Orthop Relat Res 475:336–50, 2017). A hip arthroscopy, performed using a small camera, allows surgeons to address torn cartilage inside the hip joint. Although both procedures are considered standard of care treatment options, it is unknown whether the addition of hip arthroscopy improves patient outcomes compared to a PAO alone. To delay or prevent future joint replacement surgeries, joint preservation surgery is recommended for eligible patients. While previous studies found an added cost to perform hip arthroscopies, the cost-effectiveness to Canadian Health care system is not known.

Methods

Patients randomized to the experimental group will undergo central compartment hip arthroscopy prior to completion of the PAO. Patients randomized to the control group will undergo isolated PAO. Patient-reported quality of life will be the primary outcome used for comparison between the two treatment groups as measured by The International Hip Outcome Tool (iHOT-33) (Saberi Hosnijeh et al., Arthritis Rheum 69:86–93, 2017). Secondary outcomes will include the four-square step test and sit-to-stand (validated in patients with pre-arthritic hip pain) and hip-specific symptoms and impairment using the HOOS; global health assessment will be compared using the PROMIS Global 10 Score; health status will be assessed using the EQ-5D-5L and EQ VAS questionnaires (Ganz et al., Clin Orthop Relat Res 466:264–72, 2008) pre- and post-operatively. In addition, operative time, hospital length of stay, adverse events, and health services utilization will be collected. A sub-group of patients (26 in each group) will receive a T1rho MRI before and after surgery to study changes in cartilage quality over time. A cost-utility analysis will be performed to compare costs and quality-adjusted life years (QALYs) associated with the intervention.

Discussion

We hypothesize that (1) concomitant hip arthroscopy at the time of PAO to address central compartment pathology will result in clinically important improvements in patient-reported outcome measures (PROMs) versus PAO alone, that (2) additional costs associated with hip arthroscopy will be offset by greater clinical improvements in this group, and that (3) combined hip arthroscopy and PAO will prove to be a cost-effective procedure.

Trial registration

ClinicalTrials.gov NCT03481010. Registered on 6 March 2020. Protocol version: version 3.

Lateral Center-Edge Angle Is Not Predictive of Acetabular Articular Cartilage Surface Area: Anatomic Variation of the Lunate Fossa

BACKGROUND

Surgical treatment of symptomatic femoroacetabular impingement (FAI) and dysplasia requires careful characterization of acetabular morphology. The lateral center-edge angle (LCEA) is often used to assess lateral acetabular anatomy. Previous work has questioned the LCEA as a surrogate for acetabular contact/articular cartilage surface area because of the variable morphology of the lunate fossa.

HYPOTHESIS

We hypothesized that weightbearing articular cartilage of the acetabulum would poorly correlate with LCEA secondary to significant variation in the size of the lunate fossa.

STUDY DESIGN

Cohort study (Diagnosis); Level of evidence, 3.

METHODS

Patients with 3D CT imaging undergoing either hip arthroscopy or periacetabular osteotomy for FAI or symptomatic hip instability were retrospectively identified. The LCEA and femoral head diameter were measured on an anteroposterior pelvis radiograph. Patients were grouped according to their lateral acetabular coverage as undercoverage (LCEA, <25°), normal coverage (LCEA, 25°-40°), or overcoverage (LCEA, >40°). Patients were randomly identified until each group contained 20 patients. The articular surface area was measured from preoperative 3D CT data. Linear regression analysis was performed to examine the relationship between articular surface area and LCEA. Continuous and categorical data were analyzed utilizing analysis of variance and chi-square analysis. Statistical significance was set at P < .05.

RESULTS

No difference in age (P = .52), body mass index (BMI) (P = .75), or femoral head diameter (P = .66) was noted between groups. A significant difference in articular surface area was observed between patients with undercoverage and those with overcoverage (20.4 cm² vs 24.5 cm²; P = .01). No significant difference was identified between the undercoverage and normal groups (20.4 cm² vs 23.3 cm²; P = .09) or the normal and overcoverage groups (23.3 cm² vs 24.5 cm²; P = .63). A moderate positive correlation was observed between LCEA and articular surface area across all patients (r = 0.38; P = .002) but not when patients with undercoverage were excluded (r = 0.02; P = .88). Significant variation in surface area was observed within each group such that no patient in any group was outside of 2 SDs of the means of the other groups. When patients were categorized into quartiles established by the articular surface area for the entire population, 40% of patients with overcoverage were observed in the first or second quartile (lower area).

CONCLUSION

Lateral acetabular undercoverage based on the LCEA (<25°) correlates with decreased acetabular surface area. Normal or increased acetabular coverage (LCEA, >25°), however, is not predictive of increased, normal, or decreased acetabular surface area.

What Is the Impact of Periacetabular Osteotomy Surgery on Patient Function and Activity Levels?

BACKGROUND

Periacetabular osteotomy (PAO) is a hip preserving procedure performed often in younger, highly active patients. However, counseling patients is difficult, as there are limited data regarding activity level after PAO. The purpose of this study is to analyze the physical activity levels after PAO in a large, prospective multicenter cohort.

METHODS

Prospectively collected data from a multicenter study group included 359 hips treated by PAO for hip dysplasia at a mean age of 25.1 years. Patient demographics, radiographic measures, operative data, and clinical outcomes were evaluated preoperatively, at 1 year, and at minimum 2 years postoperatively. Activity level was assessed with the University of California Los Angeles (UCLA) activity score, and patients were stratified into low activity, moderate activity, and high activity groups based on preoperative function.

RESULTS

Compared to preoperative scores across the complete cohort, postoperative UCLA scores were improved on average 0.6 points at final follow-up (P = .001). The low activity and moderate activity groups had significant improvement in UCLA scores (P < .001 and P = .0007, respectively), while the high activity groups saw a significant decrease in UCLA activity scores (P < .0001). Modified Harris Hip Score, Hip Disability and Osteoarthritis Score Pain, and Hip Disability and Osteoarthritis Score Sports and Recreation scores were significantly improved across all preoperative activity levels. Multivariable linear regression (r² = 0.45) confirmed prior ipsilateral surgery as a predictor for change in UCLA score (P = .002).

CONCLUSION

Overall, these data suggest that consistent improvements in activity level and function can be expected following PAO surgery, with greater gains experienced by patients with lower preoperative levels of activity.

Patient Engagement and Cost Savings Achieved by Automated Telemonitoring Systems Designed to Prevent and Identify Surgical Site Infections After Joint Replacement

BACKGROUND

We designed two telemonitoring text and voice messaging interventions, EpxDecolonization (EpxDecol) and EpxWound, to improve management of orthopedic joint replacement patients at Washington University. We reviewed the use of these tools for a period of 88 weeks.

METHODS

Cohorts of 1,392 and 1,753 participants completed EpxDecol and EpxWound, respectively. All patients who completed EpxDecol also completed EpxWound. We assessed patient use of and satisfaction with these interventions. A return on investment (ROI) analysis was conducted to determine the cost savings generated by EpxWound and EpxDecol.

RESULTS

The proportions of patients who responded daily to EpxDecol and EpxWound were 91.9% and 77.7%, respectively, over the lengths of each intervention. The percent of daily responders declined <5% during each intervention. Ultimately, 88.4% of EpxDecol patients and 67.8% of EpxWound patients responded to ≥80% of all messages. Median patient survey responses (n = 1,246) were 9/9 (best possible) for care, 8/9 for improved communication, and 5/9 (perfect number) for number of messages received. ROI analysis for this 88-week period showed that using EpxDecol and EpxWound to engage patients (instead of nurses calling patients) saved the equivalent of 2.275 full-time nursing equivalents per week. We calculated net savings of $260,348 with an ROI of 14.85x for 1,753 patients over 88 weeks. One-year cost savings from these interventions were $153,800 with an ROI of 14.79x.

CONCLUSIONS

EpxDecol and EpxWound may serve important roles in the perioperative process for orthopedic joint reconstruction surgery given high patient usage of and satisfaction with these interventions. Implementing EpxDecol and EpxWound for a large patient population could yield substantial cost savings and ROI.

Age and Early Revision After Primary Total Hip Arthroplasty for Osteoarthritis

Prior reports have noted an increased risk of early revision among younger patients undergoing total hip arthroplasty (THA) but have been confounded by the inclusion of various diagnoses. The purpose of this study was to assess the revision rate and the time to revision for patients undergoing THA for osteoarthritis based on age. Patients with a diagnosis of osteoarthritis who underwent both primary and revision THA at the same institution were identified. The time between primary and revision surgery and the indication for revision were collected. Patients were stratified into 2 groups based on age at the time of primary THA: 64 years or younger (group 1) or 65 years or older (group 2). Between 1996 and 2016, a total of 4662 patients (5543 hips) underwent primary THA for a diagnosis of osteoarthritis. Of these, 100 patients (104 hips) received a revision THA (62 in group 1 and 42 in group 2). Mean age was 52.7±8.4 years in group 1 vs 73.4±6.3 years in group 2 (P<.001). There was no significant difference in mean body mass index (29.7±7.3 kg/m² vs 28.4±4.6 kg/m², P=.30). Rate of revision was not significantly different between the groups (1.8% vs 2.0%, P=.7). Average time from primary to revision surgery was 3.0±3.2 years for group 1 and 1.1±2.1 years for group 2 (P=.001). Among patients undergoing primary THA for a diagnosis of osteoarthritis, younger age is not associated with an increased rate of early failure or revision. [Orthopedics. 2017; 40(6):e1069-e1073.].

Activity Level and Severity of Dysplasia Predict Age at Bernese Periacetabular Osteotomy for Symptomatic Hip Dysplasia

BACKGROUND

The age when patients present for treatment of symptomatic developmental dysplasia of the hip with periacetabular osteotomy (PAO) varies widely. Modifiable factors influencing age at surgery include preexisting activity level and body mass index (BMI). The severity of the hip dysplasia has also been implicated as a factor influencing the age at arthritis onset. The purpose of this study was to determine whether activity level, BMI, and severity of dysplasia are independent predictors of age of presentation for PAO.

METHODS

A retrospective, institutional review board-approved review of prospectively collected data from a multicenter study group identified 708 PAOs performed for developmental dysplasia of the hip. Demographic factors that were considered in the analysis included age at surgery, BMI, history of hip disorder or treatment, and duration of symptoms. The severity of the developmental dysplasia of the hip was assessed by radiographic measurement of the lateral and anterior center-edge angles and acetabular inclination. Activity level was assessed with the University of California, Los Angeles (UCLA) activity score. Spearman correlations and t tests were used for univariable analysis. Multivariable regression analysis using generalized estimating equations was applied to determine independent predictors of age at PAO.

RESULTS

Univariable analysis indicated that age at presentation for treatment of PAO correlated with the lateral and anterior center-edge angles (p < 0.001), UCLA score (p < 0.001), and BMI (p = 0.04). Since the lateral and anterior center-edge angles were similarly correlated (Spearman rho = 0.61, p < 0.001), the lateral center-edge angle alone was used to classify the severity of the developmental dysplasia of the hip. Multivariable linear regression confirmed that a high UCLA score and severe hip dysplasia were independent predictors of age at PAO (p < 0.001).

CONCLUSIONS

A high activity level and severe dysplasia lead to the development of symptoms and presentation for PAO at significantly younger ages. The combination of these two factors has an even greater effect on decreasing the age at presentation for hip-preserving surgery. An increased BMI was not independently associated with a younger age at surgery. Modifying activity level may be beneficial in terms of delaying the onset of symptoms from developmental dysplasia of the hip.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Contemporary Strategies for Rapid Recovery Total Hip Arthroplasty

Over the past several years, rapid recovery protocols for total hip arthroplasty have evolved in parallel with advancements in pain management, regional anesthesia, focused rehabilitation, and the patient selection process. As fiscal pressures from payers of health care increase, surgical outcomes and complications are being scrutinized, which evokes a sense of urgency for arthroplasty surgeons as well as hospitals. The implementation of successful accelerated recovery pathways for total hip arthroplasty requires the coordinated efforts of surgeons, practice administrators, anesthesiologists, nurses, physical and occupational therapists, case managers, and postacute care providers. To optimize performance outcomes, it is important for surgeons to select patients who are eligible for rapid recovery. The fundamental tenets of multimodal pain control, regional anesthesia, prudent perioperative blood management, venous thromboembolic prophylaxis, and early ambulation and mobility should be collectively addressed for all patients who undergo primary total hip replacement.

Does previous osteotomy compromise total hip arthroplasty? A systematic review

Hip osteotomy surgery has increased over the past several years, yet the impact of these procedures on subsequent total hip arthroplasty (THA) remains controversial. The purpose of this study was to perform a systematic review of the literature to determine the clinical results, procedure complications, and survivorship of THA following previous hip osteotomy. Ten studies met inclusion criteria. The operative time and estimated blood loss were higher in the post-osteotomy cohorts; while the clinical results and survivorship between groups were similar. THA following previous pelvic and femoral osteotomy provides pain relief and improved function with similar complication rates, clinical outcomes, and survivorship compared to hips undergoing routine primary THA. These procedures can be technically more demanding with increased operative times and intraoperative blood loss.

Reliability of a complication classification system for orthopaedic surgery

BACKGROUND

Quality of health care and safety have been emphasized by various professional and governmental groups. However, no standardized method exists for grading and reporting complications in orthopaedic surgery. Conclusions regarding outcomes are incomplete without a standardized, objective complication grading scheme applied concurrently. The general surgery literature has the Clavien-Dindo classification that meets the above criteria.

QUESTIONS/PURPOSES

We asked whether a previously reported classification would show high intraobserver and interobserver reliabilities when modified for orthopaedic surgery specifically looking at hip preservation surgery. We therefore determined the interreader and intrareader reliabilities of the adapted classification scheme as applied to hip preservation surgery.

METHODS

We adapted the validated Clavien-Dindo complication classification system and tested its reliability for orthopaedic surgery, specifically hip preservation surgery. There are five grades based on the treatment required to manage the complication and the potential for long-term morbidity. Forty-four complication scenarios were created from a prospective multicenter database of hip preservation procedures and from the literature. Ten readers who perform hip surgery at eight centers in three countries graded the scenarios at two different times. Fleiss' and Cohen's κ statistics were performed for interobserver and intraobserver reliabilities, respectively.

RESULTS

The overall Fleiss' κ value for interobserver reliability was 0.887 (95% CI, 0.855-0.891). The weighted κ was 0.925 (95% CI, 0.894-0.956) for Grade I, 0.838 (95% CI, 0.807-0.869) for Grade II, 0.87 (95% CI, 0.835-0.866) for Grade III, and 0.898 (95% CI, 0.866-0.929) for Grade IV. The Cohen's κ value for intraobserver reliability was 0.891 (95% CI, 0.857-0.925).

CONCLUSIONS

The adapted classification system shows high interobserver and intraobserver reliabilities for grading of complications when applied to orthopaedic surgery looking at complications of hip preservation surgery. This grading scheme may facilitate standardization of complication reporting and make outcome studies more comparable.

Treatment of the symptomatic healed Perthes hip

Healed Legg-Calvé-Perthes disease may cause both intra-articular and extra-articular impingement, resulting in a symptomatic hip prior to the onset of osteoarthritis. Various impingement-relieving surgeries have been used in the past; however, the development of the safe surgical dislocation technique has allowed a better understanding of complex deformity that may be present in these hips and hence may improve treatment of these symptomatic prearthritic hips. This article outlines the range of deformities possible in a Perthes hip, and treatment strategies to surgically address these deformities. For Perthes disease good preoperative clinical and radiographic assessment is essential, and intraoperative assessment vital.

Multicenter study of complications following surgical dislocation of the hip

BACKGROUND

Surgical hip dislocation enables complete exposure of the hip joint for treatment of various hip disorders.There is limited information regarding the complications associated with this procedure. Our purpose is to report the incidence of complications associated with surgical dislocation of the hip in a large, multicenter patient cohort.

METHODS

A retrospective, multicenter analysis of patients who had undergone surgical hip dislocation was performed.Patients who had undergone a simultaneous osteotomy were excluded. Complications were recorded, with specific assessment for osteonecrosis, trochanteric nonunion, femoral neck fracture, nerve injury, heterotopic ossification, and thromboembolic disease. We graded complications with a validated classification scheme that includes five grades based on the treatment required to manage the complication and any long-term morbidity. With this classification, a Grade-I complication is one that requires no change in the routine postoperative course, Grade II requires a change in outpatient management, Grade III requires invasive surgical or radiologic management, Grade IV is associated with long-term morbidity or is life-threatening,and Grade V results in death.

RESULTS

The study included 334 hips in 302 patients seen at eight different North American centers. There were eighteen complications (5.4%) that were classified as Grade I (not clinically relevant and required no deviation from routine postoperative care). There were six complications (1.8%) classified as Grade II (treated on an outpatient basis or with close observation and resolved). There were nine complications (2.7%) classified as Grade III (treatable and resolved with surgery or inpatient management). There was one complication (0.3%) classified as Grade IV (resulting in a long-term deficit). A total of thirty hips had one or more complications, for an overall incidence of 9%. Excluding heterotopic ossification, the complication rate was sixteen (4.8%) of 334.

CONCLUSIONS

Surgical hip dislocation is a safe procedure with a low complication rate. Many of the complications were clinically unimportant heterotopic ossification. There were no cases of femoral head osteonecrosis or femoral neck fracture, and, with the exception of one sciatic neurapraxia that partially resolved, no other complication resulted in long-term morbidity.

Incidence of deep vein thrombosis and pulmonary embolus following periacetabular osteotomy

BACKGROUND

Venous thromboembolism, a known complication of orthopaedic procedures, is thought to be more prevalent following hip surgery. Venous thromboembolism risk assessment and appropriate prophylaxis according to the American College of Chest Physicians guidelines has become the standard of care. However, it is accepted that venous thromboembolism prophylaxis is associated with potential adverse sequelae including hematoma, wound drainage, and infection. Little is known regarding the incidence of venous thromboembolism following periacetabular osteotomy and the necessity for and method of routine prophylaxis.

METHODS

A total of 1067 periacetabular osteotomies performed at six North American centers utilizing different methods of prophylaxis against venous thromboembolism were analyzed for type of prophylaxis and incidence of clinically symptomatic venous thromboembolism.

RESULTS

There were four cases of pulmonary embolus and seven cases of deep vein thrombosis. There were no reported deaths. The crude incidence of clinically symptomatic venous thromboembolism was 9.4 per 1000 procedures.

CONCLUSIONS

The risk from chemoprophylaxis and the development of hematoma may be greater than the risk of clinically important venous thromboembolism in patients undergoing periacetabular osteotomy.

Acetabular labral tears of the hip in women

Acetabular labral tears are a major cause of hip dysfunction in young patients and a primary precursor to hip osteoarthritis. In addition, labral disease more commonly occurs in women and can present with nonspecific symptoms. It is possible to diagnose, quantify, and treat labral tears before the onset of secondary joint deterioration. However, the diagnosis requires a high index of suspicion, special attention to subtle patterns of presentation, and timely consideration for imaging studies. Treatment options are still evolving and include a wide array of nonsurgical and surgical techniques. Treatment should also address secondary dysfunction that can be associated with hip pathology. An initial trial of conservative management is recommended and failure to progress is an indication for surgical consultation.

Perioperative antibiotics should not be withheld in proven cases of periprosthetic infection

Intraoperative tissue or fluid culture remains the gold standard in diagnosing periprosthetic infection. However, an organism is not always isolated from intraoperative cultures. We asked whether preoperative antibiotics interfered with the isolation of organisms from intraoperative tissue samples. We hypothesized organisms isolated from preoperative joint aspirate correspond to those cultures from intraoperative specimens. We retrospectively reviewed 171 patients undergoing TKA, diagnosed with periprosthetic infections from 2000 to 2005, who had a positive preoperative aspiration culture. The details of any antibiotics given to the patients preoperatively were documented. Seventy-two of 171 patients received preoperative antibiotics before surgery. Intraoperative culture was negative in nine of the 72 patients who received antibiotics: a false-negative rate of 12.5%. An organism could not be isolated from intraoperative samples in eight of the 99 patients who did not receive preoperative antibiotics: a false-negative rate of 8%. We observed no difference in the incidence of false-negative cultures between the two groups. The organisms isolated from the aspirate culture were identical to their intraoperative counterparts in 97% of the cases. Administration of preoperative antibiotics to patients with a positive preoperative joint aspirate did not interfere with the isolation of the infecting organism from intraoperative culture samples more than when antibiotics were withheld.

Prospective dosing of warfarin based on cytochrome P-450 2C9 genotype

Cytochrome P-450 2C9 (CYP2C9) polymorphisms (CYP2C9*2 and CYP2C9*3) reduce the clearance of warfarin, increase the risk of bleeding, and prolong the time to stable dosing. Whether prospective use of a retrospectively developed algorithm that incorporates CYP2C9 genotype and nongenetic factors can ameliorate the propensity to bleeding and delay in achieving a stable warfarin dose is unknown. We initiated warfarin therapy in 48 orthopedic patients tailored to the following variables: CYP2C9 genotype, age, weight, height, gender, race, and use of simvastatin or amiodarone. By using pharmacogenetics-based dosing, patients with a CYP2C9 variant achieved a stable, therapeutic warfarin dose without excessive delay. However compared to those without a CYP2C9 variant, patients with a variant continued to be at increased risk (hazard ratio 3.6, 95% confidence interval 1.4-9.5, p = 0.01) for an adverse outcome (principally INR > 4), despite pharmacogenetics-based dosing. There was a linear relationship (R(2) = 0.42, p < 0.001) between the pharmacogenetics-predicted warfarin doses and the warfarin maintenance doses, prospectively validating the dosing algorithm. Prospective, perioperative pharmacogenetics-based dosing of warfarin is feasible; however, further evaluation in a randomized, controlled study is recommended.

Stimulation of BMP-2 expression by pro-inflammatory cytokines IL-1 and TNF-alpha in normal and osteoarthritic chondrocytes

BACKGROUND

Destruction of cartilage in osteoarthritis is a direct effect of an imbalance between catabolic and anabolic activities in the tissue. While a great deal is known about catabolism, we sought to determine the biochemical basis of the anabolic activity.

METHODS

Cartilage was isolated from normal and osteoarthritic patients and subjected to both cell and explant culture. mRNA expression levels of the growth and differentiation factors bone morphogenetic protein-2 (BMP-2), BMP-4, BMP-6, cartilage-derived morphogenetic protein-1 (CDMP-1), connective tissue growth factor (CTGF), and activin were determined. BMP-2 was localized in osteoarthritic cartilage by immunohistochemistry. To determine the mechanism of BMP-2 stimulation, chondrocytes were cultured with TGF-beta (transforming growth factor-beta), insulin-like growth factor-1 (IGF-1), interleukin-1beta (IL-1beta), and tumor necrosis factor-alpha (TNF-alpha). The BMP-2 response was monitored by quantitative real-time polymerase chain reaction to ascertain mRNA levels and by Western blot analysis, BMP-2 protein quantitation, and immunohistochemistry to determine protein levels.

RESULTS

BMP-2 was found to be up-regulated in osteoarthritic chondrocytes and cartilage. In cell culture, IL-1beta and TNF-alpha increased BMP-2 mRNA and protein levels by eightfold and fifteenfold, respectively, whereas IGF-1 and TGF-beta1 had no effect. In cartilage explant cultures, IL-1beta and TNF-alpha increased BMP-2 levels both intracellularly and extracellularly. Functional relevance was suggested by co-localization of BMP-2 and newly synthesized type-II procollagen within the same cells.

CONCLUSIONS

BMP-2 acts as a stimulus of anabolic activities in normal and osteoarthritic chondrocytes. Furthermore, the pro-inflammatory cytokines IL-1beta and TNF-alpha, known to be present in synovium and cartilage of patients with osteoarthritis, stimulate the production of active BMP-2.

The isolation and partial characterization of a rat incisor dentin matrix polypeptide with in vitro chondrogenic activity

In vivo implants of demineralized dentin matrix into muscle induce the formation of bone within the muscle. As with bone matrix implants, the bone induction appears to follow a chondrogenic pathway. Outgrowth cells from explants of neonatal rat muscle respond to bone matrix, in vitro, by expressing a heightened synthesis of sulfated proteoglycans and type II collagen, phenotypic of cartilage. The in vitro cell culture system has been used as an assay to monitor the isolation of the factor responsible for expression of this phenotypic transformation. Soluble proteins extracted from rat incisor dentin matrix during demineralization with EDTA, and not precipitable with 1.0 M CaCl2, were active in the in vitro system. The active extract was fractionated by Sephacryl S-100 chromatography in 6 M guanidine HCl, isoelectric focusing in Immobilines, and by reverse phase high performance liquid chromatography. All fractions were assayed for activity at every stage. The final active fraction from the reverse phase chromatography on a Zorbax Poly-F column was purified to homogeneity, and yielded a single spot on two-dimensional gel electrophoresis. The component, RP-4, had pI 5.4-5.5, and an apparent Mr 6,000-10,000, based on globular protein standards. Maximal activity with respect to both sulfate incorporation into proteoglycan and production of type II collagen was in the 1.0-10 ng/ml range. The RP-4 had a unique amino-terminal amino sequence and was rich in Gly, Pro, Glx, and Ala residues. It was different from transforming growth factor-beta and the bone morphogenetic protein family of proteins in these essential features.

Rat incisor dentine contains a factor which alters the phenotypic expression and stimulates chondrogenesis in fibroblast-like cells in vitro

A low molecular weight protein fraction isolated under dissociative conditions during the demineralization of rat incisor dentine has the ability to modulate, in culture, the expression of fibroblast-like cells explanted from neonatal rat muscle. The protein fraction enhances the incorporation of 35S-sulphate into a proteoglycan larger in weight than that produced by the uninduced cells; furthermore it induces the production of type II collagen. These changes take place in the absence of cell proliferation as measured by 3H-thymidine incorporation. The altered fibroblast-like cells form nodules and secrete an abundant extracellular matrix which stains for proteoglycan after 7-9 days in culture. These data show that the dentine matrix does contain a factor which can initiate a mitogenesis-independent alteration in the expression of the muscle-explant outgrowth cells. Those changes are consistent with a shift to a chondrogenic mode.

A search for the osteogenic factor in dentin. Rat incisor dentin contains a factor stimulating rat muscle cells in vitro to incorporate sulfate into an altered proteoglycan

Demineralized dentin matrix has the capacity to induce bone formation via a chondrogenic pathway when implanted into muscle, in a fashion entirely analogous to bone matrix implants. In this work we have attempted to isolate, from rat incisor dentin, the matrix factor responsible for initiating osteogenesis. Rat incisor dentin was demineralized with EDTA plus 4.0 M guanidine. HCl. The proteins in the extracts were collected and, after a CaCl2 precipitation step, fractionated on Sephacryl S-200 in 6.0 M guanidine. HCl. The primary assay for activity was the incorporation of 35S-sulfate into proteoglycan in cultures of the fibroblast-like outgrowth cells from explants of neonatal rat muscle. Two Sephacryl S-200 fractions showed enhanced sulfate incorporating activity, but only one showed enhanced incorporation without a concomitant increase in cell number. In the presence of this fraction, the cell cultures produced a larger amount of a new small proteoglycan, as compared to controls, and a significant amount of a much larger proteoglycan. The active fraction had proteins in the Mr range from 8,000 to 15,000 as the major components. These data suggest that the fraction identified may contain the factors responsible for initiating the osteogenic response to dentin matrix upon its implantation in muscle in vivo.

Matrix proteins of the teeth of the sea urchin Lytechinus variegatus

The teeth of the sea urchin Lytechinus variegatus grow continuously. The mineral phase, a high magnesium calcite, grows into single crystals within numerous compartments bounded by an organic matrix deposited by the odontoblasts. Electron microscopic examination of glutaraldehyde-fixed Ethylene Diamine Tetra acetic acid (EDTA) demineralized teeth shows the compartment walls to be organized from multiple layers of cell membrane which might contain cytoplasmic protein inclusions. Proteins extracted during demineralization of unfixed teeth were examined by gel electrophoresis, high performance liquid chromatography, and amino acid analysis. The tooth proteins were acidic, they contained phosphoserine, and they were rich in aspartic acid. By contrast, the proteins of similarly extracted mineralized Aristotle's lantern skeletal elements were nonphosphorylated and were rich in glutamic acid. Vertebrate tooth and bone matrix proteins show similar differences. Surprisingly, an antibody to the principle rat incisor phosphoprotein showed a significant cross-reactivity with the urchin tooth protein, by dot-blot and enzyme-linked immunosorbent assay procedures. Thus, the urchin tooth proteins contain epitope regions similar to those which are phenotypic markers of vertebrate odontoblasts. Whether this is an expression of convergent or divergent evolutionary processes, it is likely that the matrix proteins play a similar role in matrix mineralization. The sea urchin tooth may thus be an excellent model for the study of odontoblast-mediated mineral-matrix relationships.