Identifying treatment responders using counterfactual modeling and potential outcomes

Individualizing treatment according to patients' characteristics is central for personalized or precision medicine. There has been considerable recent research in developing statistical methods to determine optimal personalized treatment strategies by modeling the outcome of patients according to relevant covariates under each of the alternative treatments, and then relying on so-called predicted individual treatment effects. In this paper, we use potential outcomes and principal stratification frameworks and develop a multinomial model for left and right-censored data to estimate the probability that a patient is a responder given a set of baseline covariates. The model can apply to RCT or observational study data. This method is based on the monotonicity assumption, which implies that no patients would respond to the control treatment but not to the experimental one. We conduct a simulation study to evaluate the properties of the proposed estimation method. Results showed that the predictions of the probability of being a responder were well calibrated even if we observed variability and a small bias when many parameters were estimated. We finally applied the method to a cohort study on the selection of patients for additional radiotherapy after resection of a soft-tissue sarcoma.

Patients with Revision Modern Megaprostheses of the Distal Femur Have Improved Disease-Specific and Health-Related Outcomes Compared to Those with Primary Replacements

We asked whether there would be any difference between primary and revision modern cemented fixed hinge megaprosthesis of the distal femur in function and activity-related outcomes following treatment of a bone tumor. An identical custom-made fixed hinge cemented megaprosthesis with a hydroxyapatite collar was used in all cases. The main outcomes were joint-specific function, disease-specific activity, and health-related quality of life. Implant survival was also evaluated. Patients in the revision group performed slightly better than patients in the primary group on disease-specific (Toronto Extremity Salvage Score, p = 0.033; Musculoskeletal Tumor Society, p = 0.072) and health-related outcomes (Short Form 36 [SF-36] physical component, p = 0.085; SF-36 mental component, p = 0.069) but not on joint-specific outcomes (Knee Society Score, p = 0.94). The cumulative probabilities of revision for any reason were 14.5% (7-25%) at 5 years with no statistically significant difference between primary and revision procedures (p = 0.77). In conclusion, patients undergoing a revision have similar joint-specific functional outcome but improved disease-specific and health-related outcomes. Implant survival are similar between groups.

The indications and donor-site morbidity of tibial cortical strut autografts in the management of defects in long bones

Aims

The primary aim of this study was to determine the morbidity of a tibial strut autograft and characterize the rate of bony union following its use.

Patients and Methods

We retrospectively assessed a series of 104 patients from a single centre who were treated with a tibial strut autograft of > 5 cm in length. A total of 30 had a segmental reconstruction with continuity of bone, 27 had a segmental reconstruction without continuity of bone, 29 had an arthrodesis and 18 had a nonunion. Donor-site morbidity was defined as any event that required a modification of the postoperative management. Union was assessed clinically and radiologically at a median of 36 months (IQR, 14 to 74).

Results

Donor-site morbidity occurred in four patients (4%; 95% confidence interval (CI) 1 to 10). One patient had a stress fracture of the tibia, which healed with a varus deformity, requiring an osteotomy. Two patients required evacuation of a haematoma and one developed anterior compartment syndrome which required fasciotomies. The cumulative probability of union was 90% (95% CI 80 to 96) at five years. The type of reconstruction (p = 0.018), continuity of bone (p = 0.006) and length of tibial graft (p = 0.037) were associated with the time to union.

Conclusion

The tibial strut autograft has a low risk of morbidity and provides adequate bone stock for treating various defects of long bones. Cite this article: Bone Joint J 2018;100-B:667-74.

Reporting of heterogeneity of treatment effect in cohort studies: a review of the literature

Background

This article corresponds to a literature review and analyze how heterogeneity of treatment (HTE) is reported and addressed in cohort studies and to evaluate the use of the different measures to HTE analysis.

Methods

prospective cohort studies, in English language, measuring the effect of a treatment (pharmacological, interventional, or other) published among 119 core clinical journals (defined by the National Library of Medicine) in the last 16 years were selected in the following data source: Medline. One reviewer randomly sampled journal articles with 1: 1 stratification by journal type: high impact journals (the New England Journal of Medicine, JAMA, LANCET, Annals of Internal Medicine, BMJ and Plos Medicine) and low impact journal (the remaining journals) to identify 150 eligible studies. Two reviewers independently and in duplicate used standardized piloted forms to screen study reports for eligibility and to extract data. They also used explicit criteria to determine whether a cohort study reported HTE analysis. Logistic regression was used to examine the association of prespecified study characteristics with reporting versus not reporting of heterogeneity of treatment effect.

Results

One hundred fifty cohort studies were included of which 88 (58%) reported HTE analysis. High impact journals (Odds Ratio: 3.5, 95% CI: 1.78–7.5; P < 0.001), pharmacological studies (Odds Ratio: 0.26, 95% CI: 0.13–0.51; P < 0.001) and studies published after 2014 (Odds Ratio: 0.5, 95% CI: 0.25–0.97; P = 0.004) were associated with more frequent reporting of HTE. 27 (31%) studies which reported HTE used an interaction test.

Conclusion

More than half cohort studies report some measure of heterogeneity of treatment effect. Prospective cohort studies published in high impact journals, with large sample size, or studying a pharmacological treatment are associated with more frequent HTE reporting. The source of funding was not associated with HTE reporting. There is a need for guidelines on how to perform HTE analyses in cohort studies.

Electronic supplementary material

The online version of this article (10.1186/s12874-017-0466-6) contains supplementary material, which is available to authorized users.

Using Bayesian statistics to estimate the likelihood a new trial will demonstrate the efficacy of a new treatment

Background

The common frequentist approach is limited in providing investigators with appropriate measures for conducting a new trial. To answer such important questions and one has to look at Bayesian statistics.

Methods

As a worked example, we conducted a Bayesian cumulative meta-analysis to summarize the benefit of patient-specific instrumentation on the alignment of total knee replacement from previously published evidence. Data were sourced from Medline, Embase, and Cochrane databases. All randomised controlled comparisons of the effect of patient-specific instrumentation on the coronal alignment of total knee replacement were included. The main outcome was the risk difference measured by the proportion of failures in the control group minus the proportion of failures in the experimental group. Through Bayesian statistics, we estimated cumulatively over publication time of the trial results: the posterior probabilities that the risk difference was more than 5 and 10%; the posterior probabilities that given the results of all previous published trials an additional fictive trial would achieve a risk difference of at least 5%; and the predictive probabilities that observed failure rate differ from 5% across arms.

Results

Thirteen trials were identified including 1092 patients, 554 in the experimental group and 538 in the control group. The cumulative mean risk difference was 0.5% (95% CrI: −5.7%; +4.5%). The posterior probabilities that the risk difference be superior to 5 and 10% was less than 5% after trial #4 and trial #2 respectively. The predictive probability that the difference in failure rates was at least 5% dropped from 45% after the first trial down to 11% after the 13th. Last, only unrealistic trial design parameters could change the overall evidence accumulated to date.

Conclusions

Bayesian probabilities are readily understandable when discussing the relevance of performing a new trial. It provides investigators the current probability that an experimental treatment be superior to a reference treatment. In case a trial is designed, it also provides the predictive probability that this new trial will reach the targeted risk difference in failure rates.

Trial registration

CRD42015024176.

Electronic supplementary material

The online version of this article (doi:10.1186/s12874-017-0401-x) contains supplementary material, which is available to authorized users.

Learning curves for three specific procedures by anesthesiology residents using the learning curve cumulative sum (LC-CUSUM) test

BACKGROUND

The learning curve cumulative sum (LC-CUSUM) test is an innovative tool that allows quantitative monitoring of individual medical performance during the learning process by determining when a predefined acceptable level of performance is reached. This study used the LC-CUSUM test to monitor the learning process and failure rate of anesthesia residents training for specific subspecialty anesthesia procedures.

METHODS

The study included 490 tracheal punctures (TP) for jet ventilation, 340 thoracic epidural analgesia (TEA) procedures, and 246 fiberoptic nasal intubations (FONI) performed by 18 residents during their single 6-month rotation.

RESULTS

Overall, 27 (14-52), 19 (5-41), and 14 (6-33) TP, TEA, and FONI procedures were performed, respectively, by each resident. In total, 2 of 18 residents achieved an acceptable failure rate for TEA according to the literature and 4 of 18 achieved an acceptable failure rate for FONI, while none of the residents attained an acceptable rate for TP.

CONCLUSIONS

A single 6-month rotation in a reference teaching center may not be sufficient to train residents to perform specific or sub-specialty procedures as required. A regional learning network may be useful. More patient-based data are necessary to conduct a risk adjustment analysis for such specific procedures.

Validity and Reliability of Intraoperative Radiographs to Assess Leg Length During Total Hip Arthroplasty: Correlation and Reproducibility of Anatomic Distances

BACKGROUND

Leg length discrepancy after total hip arthroplasty is a frequent complication. The aim of this study was to assess the validity (correlation) and reproducibility (inter-rater agreement) of various intraoperative hip radiographs measures to estimate leg length.

METHODS

Patients were included if they were aged 15 years or older; were eligible for a total hip arthroplasty, and were operated in lateral recumbent. An intraoperative hip radiograph was performed with the definitive implants in place. At 6 weeks postoperatively, anteroposterior pelvis radiograph was taken. We used 3 measures to assess leg length: the height from the ischial tuberosity to the lesser trochanter (LTI), the height from the center of femoral head to the greater trochanter (GTC), and to the inferior teardrop (TC).

RESULTS

The study group consisted of 71 hips with an average age of 69 years (range, 24-92 years). The correlation was 0.545 (95% CI: 0.35-0.69) for GTC, 0.75 (95% CI: 0.61-0.84) for TC, and 0.70 (95% CI: 0.56-0.80) for LTI. Intraoperative and postoperative measures were statistically different for GTC (<0.0001) and TC (<0.0001), and not significant for LTI (P = .06). Reproducibility of these measures were excellent with intraclass correlation coefficients of 0.977, 0.814, and 0.983 for the GTC, TC, and LTI, respectively.

CONCLUSION

None of the parameters used to assess leg-length based on an intraoperative radiograph showed good correlation with the postoperative radiograph.

Tumor endoprosthesis revision rates increase with peri-operative chemotherapy but are reduced with the use of cemented implant fixation

Chemotherapy may reduce osseointegration of tumor endoprosthesis, while delaying chemotherapy may reduce survival. We studied the effects of chemotherapy and cemented fixation on tumor endoprosthesis survivorship with a retrospective analysis of 50 consecutive patients receiving lower limb salvage surgery. We compared rates of radiographic loosening/revision and effect of cement fixation between chemotherapy/no chemotherapy cohorts. Chemotherapy increased the total revision rate (HR = 3.8 [1-14], P = 0.033), but did not affect aseptic loosening. Cement fixation reduced revision for loosening (HR = 0.09 (0.008-0.98), P = 0.012) and showed less radiographic loosening (HR = 0.09 (0.02-0.51), P = 0.00066). Cement fixation had lower rates of revision for loosening and radiographic loosening regardless of whether chemotherapy was given. We conclude that for these implants, cement fixation provides superior results to uncemented fixation.

Proficiency in oocyte retrieval assessed by the learning curve cumulative summation test

The number of procedures required for a trainee to reach proficiency in oocyte retrieval and the criteria applied to define performance are not well defined. To evaluate the learning curve of oocyte retrieval, this study prospectively evaluated three trainees over 6 months. Oocyte retrieval was monitored by the learning curve-cumulative summation test (LC-CUSUM), a specific statistical tool designed to indicate when a predefined level of performance is reached. Oocytes were retrieved from one ovary by the trainee and from the second ovary by a senior operator in a randomized manner. The main outcome measure was the ratio of oocytes collected and follicles aspirated. A trainee's ratio of ≥ 80% of the senior operator's defined success. From 17 to >50 procedures were necessary for the trainees to reach the predefined level of performance. Cumulative summation tests implemented after the learning phase confirmed that performance was maintained. The present study confirms the large variability in acquiring proficiency for surgical procedures. It provides an exportable model for a quantitative tailored monitoring of the learning curve and for continuous monitoring of performance in oocyte retrieval.

Learning curve of acetabular cup positioning in total hip arthroplasty using a cumulative summation test for learning curve (LC-CUSUM)

Despite advances in surgical techniques and instrumentation, optimal cup positioning in total hip arthroplasty (THA) is challenging with a limited accuracy. We evaluated whether a learning curve exists for the optimal cup positioning, using the LC-CUSUM test (Learning curve cumulative summation test). We evaluated the first 100 consecutive THA performed by two surgeons, who had a year of fellowship training in the same teaching hospital. A learning curve of cup positioning was plotted in each series using the LC-CUSUM score. There was no significant difference of numbers of outlier between two surgeons (P = 0.079). Both surgeons completed the learning curve of optimal cup positioning before 50 procedures, and maintained competence. A substantial learning period is necessary in the optimal positioning of an acetabular cup.

Student attainment of proficiency in a clinical skill: the assessment of individual learning curves

The aims of this study were to determine if the learning curve cumulative summation test (LC-CUSUM) can differentiate proficiency in placing intravenous catheters by novice learners, and identify the cause of failure when it occurred. In a prospective, observational study design 6 undergraduate students with no previous experience of placing intravenous catheters received standardized training by a board certified veterinary anesthesiologist in intravenous catheter placement technique. Immediately following training, each student attempted 60 intravenous catheterizations in a dog mannequin thoracic limb model. Results were scored as a success or failure based upon completion of four specific criteria, and where catheter placement failure occurred, the cause was recorded according to pre-defined criteria. Initial acceptable and unacceptable failure rates were set by the study team and the LC-CUSUM was used to generate a learning curve for each student. Using 10% and 25% acceptable and unacceptable failure rates, 3 out of 6 students attained proficiency, requiring between 26 to 48 attempts. Applying 25% and 50% acceptable and unacceptable failure rates, 5 of 6 students obtained proficiency, requiring between 18 and 55 attempts. Wide inter-individual variability was observed and the majority of failed catheterisation attempts were limited to two of the four pre-defined criteria. These data indicate that the LC-CUSUM can be used to generate individual learning curves, inter-individual variability in catheter placement ability is wide, and that specific steps in catheter placement are responsible for the majority of failures. These findings may have profound implications for how we teach and assess technical skills.

Using the CUSUM test to control the proportion of inadequate open biopsies of musculoskeletal tumors

BACKGROUND

Biopsies of musculoskeletal tumors lead to alterations in treatment in almost 20% of cases. Control charts are useful to ensure that a process is operating at a predetermined level of performance, although their use has not been demonstrated in assessing the adequacy of musculoskeletal biopsies.

QUESTIONS/PURPOSES

We therefore (1) assessed the incidence of and the reasons for inadequate musculoskeletal biopsies when following guidelines for performing the procedure; and (2) implemented a process control chart, the CUSUM test, to monitor the proportion of inadequate biopsies.

METHODS

We prospectively studied 116 incisional biopsies. The biopsy was performed according to 10 rules to (1) minimize contamination in the tissues surrounding the tumor; and (2) improve accuracy. A frozen section was systematically performed to confirm that a representative specimen was obtained. Procedures were considered inadequate if: (1) another biopsy was necessary; (2) the biopsy tract was not appropriately placed; and (3) the treatment provided based on the diagnosis from the biopsy was not appropriate.

RESULTS

Five (4.3%) of the 116 incisional biopsy procedures were considered failures. Three patients required a second repeat open biopsy and two were considered to receive inappropriate treatment. No alarm was raised by the control chart and the performance was deemed adequate over the monitoring period.

CONCLUSIONS

The proportion of inadequate musculoskeletal open biopsies performed at a referral center was low. Using a statistical process control method to monitor the failures provided a continuous measure of the performance.

No difference in quality-of-life outcomes after mobile and fixed-bearing medial unicompartmental knee replacement

This is a retrospective study comparing the clinical outcomes of mobile vs fixed medial unicompartmental knee replacements. Patients were identified from a prospectively collected database. Demographic data and pre- and postoperative outcomes (Oxford, Western Ontario and McMaster Universities Osteoarthritis Index, Short Form Health Survey-12, and satisfaction) were collected-104 knees (90 patients) with minimum 2-years of follow-up: 37 mobile and 67 fixed-bearing. At baseline, the median age was 60 years (mobile) and 66 (fixed); body mass index was significantly higher (32) for the mobile group than for the fixed (28). At follow-up, the groups differed only in the Oxford score: median 83 (mobile) and 90 (fixed). There is no difference in outcomes between mobile and fixed unicompartmental knee replacements.

Effects of neoadjuvant chemotherapy on image-directed planning of surgical resection for distal femoral osteosarcoma

BACKGROUND

Standard therapy for localized osteosarcoma includes neoadjuvant chemotherapy preceding local control surgery, followed by adjuvant chemotherapy. When limb-salvage procedures were being developed, preoperative chemotherapy allowed a delay in definitive surgery to permit fabrication of custom endoprosthetic reconstruction implants. One rationale for its continuation as the care standard has been the perception that it renders surgery easier and safer. Our objective was to compare surgical procedures planned on the basis of magnetic resonance images (MRIs) of distal femoral osteosarcomas acquired before neoadjuvant chemotherapy with surgical procedures planned on the basis of MRIs acquired after neoadjuvant chemotherapy as a measure of the surgically critical anatomic effects of the chemotherapy.

METHODS

Twenty-four consecutive patients with distal femoral osteosarcoma had available digital MRIs preceding and following neoadjuvant chemotherapy. Thorough questionnaires were used to catalogue surgically critical anatomic details of MRI-directed surgical planning. Four faculty musculoskeletal oncologic surgeons and two musculoskeletal radiologists evaluated the blinded and randomly ordered MRIs. Interrater and intrarater reliabilities were calculated with intraclass correlation coefficients. The Student t test and chi-square test were used to compare pre-chemotherapy and post-chemotherapy continuous and categorical variables on the questionnaire. Mixed-effect regression models were employed to compare surgical procedures planned on the basis of pre-chemotherapy MRIs and with those planned on the basis of post-chemotherapy MRIs.

RESULTS

The blinded reviews generated strong intraclass correlation coefficients for both interrater (0.772) and mean intrarater (0.778) reliability. The MRI-planned resections for the majority of tumors changed meaningfully after chemotherapy, but in inconsistent directions. On the basis of mixed-effect regression modeling, it appeared that more amputations were planned on the basis of post-chemotherapy MRIs. No other parameters differed in a significant and clinically meaningful fashion. Surgeons demonstrated their expectation that neoadjuvant chemotherapy would improve resectability by planning more radical surgical procedures on the basis of scans that they predicted had been obtained pre-chemotherapy.

CONCLUSIONS

Surgeons can reliably record the anatomic details of a planned resection of an osteosarcoma. Such methods may be useful in future multi-institutional clinical trials or registries. The common belief that neoadjuvant chemotherapy increases the resectability of extremity osteosarcomas remains anecdotally based. Rigorous assessment of this phenomenon in larger cohorts and at other anatomic sites as well as re-evaluation of other arguments for neoadjuvant chemotherapy should be considered.

Monitoring the one year postoperative infection rate after primary total hip replacement

PURPOSE

Infection of a total hip replacement is potentially a devastating complication. Statistical process control methods have been generating interest as a means of improving the quality of healthcare, and we report our experience with the implementation of such a method to monitor the one year infection rate after primary total hip replacement.

METHOD

Infection was defined as the growth of the same organism in cultures of at least two aspirates or intra-operative specimens, or growth of one pathogen in a patient with local signs of infection such as erythema, abscess or draining sinus tract. The cumulative summation test (CUSUM test) was used to continuously monitor the one year postoperative infection rate. The target performance was 0.5% and the test was set to detect twice that rate.

RESULTS

Over the three year study period, 2006 primary total hip replacements were performed. Infection developed within one year after surgery in eight (0.4%) hips. The CUSUM test generated no alarms during the study period, indicating that there was no evidence that the process was out of control.

CONCLUSION

The one year infection rate after primary total hip replacement was in control. The CUSUM test is a useful method to continuously ensure that performance is maintained at an adequate level.

Local recurrence of localized soft tissue sarcoma: a new look at old predictors

BACKGROUND

The objective of this study was to examine the effect of known predictors of local recurrence of soft tissue sarcoma in a competing risk setting.

METHODS

The outcome of interest was the cumulative probability of local recurrence per category of relevant predictors, with death as a competing event. In total, 1668 patients with a localized soft tissue sarcoma of the extremity or trunk were included.

RESULTS

Tumor size (hazard ratio, 3.3), depth (hazard ratio, 3.2), and histologic grade (hazard ratio, 4.5) were the variables that had the most effect on the risk of metastasis and, accordingly, were the most likely to induce competition. Surgical margins (hazard ratio, 3.3), histologic grade (hazard ratio, 2.1), presentation status (hazard ratio, 2.4), and tumor depth (hazard ratio, 1.5) were the variables that had the most effect on the risk of local recurrence. The 10-year cumulative probabilities of local recurrence were markedly different within categories for presentation status (P < .001) and surgical margin status (P < .001). However, because of the competing effect of death, there was little difference in the 10-year cumulative probabilities of local recurrence with regard to tumor depth (12% and 11.4% for deep and superficial tumors, respectively; P = .2), tumor size (10.6% and 13.3% for large and small tumors, respectively; P = .99), or histologic tumor grade (12.6%, 10.7%, and 11.1% for high, intermediate, and low-grade tumors, respectively; P = .17).

CONCLUSIONS

Because of the competition between local recurrence and death, histologic tumor grade, tumor size, and tumor depth had little influence on the cumulative probability of local recurrence. The authors concluded that local management should be based on presentation status and surgical margins rather than other, previously acknowledged factors.

Incidence, predictive factors, and prognosis of chondrosarcoma in patients with Ollier disease and Maffucci syndrome: an international multicenter study of 161 patients

BACKGROUND

Enchondromatosis is characterized by the presence of multiple benign cartilage lesions in bone. While Ollier disease is typified by multiple enchondromas, in Maffucci syndrome these are associated with hemangiomas. Studies evaluating the predictive value of clinical symptoms for development of secondary chondrosarcoma and prognosis are lacking. This multi-institute study evaluates the clinical characteristics of patients, to get better insight on behavior and prognosis of these diseases.

METHOD

A retrospective study was conducted using clinical data of 144 Ollier and 17 Maffucci patients from 13 European centers and one national databank supplied by members of the European Musculoskeletal Oncology Society.

RESULTS

Patients had multiple enchondromas in the hands and feet only (group I, 18%), in long bones including scapula and pelvis only (group II, 39%), and in both small and long/flat bones (group III, 43%), respectively. The overall incidence of chondrosarcoma thus far is 40%. In group I, only 4 patients (15%) developed chondrosarcoma, in contrast to 27 patients (43%) in group II and 26 patients (46%) in group III, respectively. The risk of developing chondrosarcoma is increased when enchondromas are located in the pelvis (odds ratio, 3.8; p = 0.00l).

CONCLUSIONS

Overall incidence of development of chondrosarcoma is 40%, but may, due to age-dependency, increase when considered as a lifelong risk. Patients with enchondromas located in long bones or axial skeleton, especially the pelvis, have a seriously increased risk of developing chondrosarcoma, and are identified as the population that needs regular screening on early detection of malignant transformation.

Fixation of pathological humeral fractures by the cemented plate technique

Pathological fractures of the humerus are associated with pain, morbidity, loss of function and a diminished quality of life. We report our experience of stabilising these fractures using polymethylmethacrylate and non-locking plates. We undertook a retrospective review over 20 years of patients treated at a tertiary musculoskeletal oncology centre. Those who had undergone surgery for an impending or completed pathological humeral fracture with a diagnosis of metastatic disease or myeloma were identified from our database. There were 63 patients (43 men, 20 women) in the series with a mean age of 63 years (39 to 87). All had undergone intralesional curettage of the tumour followed by fixation with intramedullary polymethylmethacrylate and plating. Complications occurred in 14 patients (22.2%) and seven (11.1%) required re-operation. At the latest follow-up, 47 patients (74.6%) were deceased and 16 (25.4%) were living with a mean follow-up of 75 months (1 to 184). A total of 54 (86%) patients had no or mild pain and 50 (80%) required no or minimal assistance with activities of daily living. Of the 16 living patients none had pain and all could perform activities of daily living without assistance. Intralesional resection of the tumour, filling of the cavity with cement, and plate stabilisation of the pathological fracture gives immediate rigidity and allows an early return of function without the need for bony union. The patient's local disease burden is reduced, which may alleviate tumour-related pain and slow the progression of the disease. The cemented-plate technique provides a reliable option for the treatment of pathological fractures of the humerus.

Adverse Effect of Older Age on the Recurrence of Soft Tissue Sarcoma of the Extremities and Trunk

Purpose

To examine the effect of age on the recurrence of soft tissue sarcoma in the extremities and trunk.

Patients and Methods

This was a multicenter study that included 2,385 patients with median age at surgery of 57 years. The end points considered were local recurrence and metastasis. Cox proportional hazards models were used to estimate hazard ratios across the age ranges with and without adjustment for known confounding factors.

Results

Older patients presented with tumors that were larger (P < .001) and of higher grade (P < .001). The proportion of positive margins increased significantly as patients age (P < .001), but radiation therapy was relatively underused in patients older than age 60 years. The 5-year cumulative incidences of local recurrence were 7.2% (95% CI, 4% to 11.7%) for patients age 30 years or younger and 12.9% (95% CI, 9.1% to 17.5%) for patients age 75 years or older. The corresponding 5-year cumulative incidences of metastasis were 17.5% (95% CI, 12.1% to 23.7%) and 33.9% (95% CI, 28.1% to 39.8%) for the same groups. Regression models showed that age was significantly associated with local recurrence (P < .001) and metastasis (P < .001) in nonadjusted models. After adjusting for imbalance in presentation and treatment variables, age remained significantly associated with local recurrence (P = .031) and metastasis (P = .019).

Conclusion

Older patients have worse outcomes because they tend to present with worse tumors and are treated less aggressively. However, there remained a significant increase in the risk of both local and systemic recurrence associated with increasing age that could not be explained by tumor or treatment characteristics.

Intraoperative ultrasonography during percutaneous Achilles tendon repair

BACKGROUND

The purpose of the study was to determine whether real-time intraoperative ultrasonography improved implant positioning and stump approximation in patients with acute Achilles tendon rupture managed percutaneously.

MATERIALS AND METHODS

The needles were introduced percutaneously without ultrasonography and their position was checked relative to cutaneous landmarks and by palpation. Then, intraoperative ultrasonography was performed to assess needle position at the proximal tendon segment, tendon tear, and distal tendon segment. Incorrectly placed needles were removed and reinserted under real-time ultrasonographic guidance. Tendon apposition was checked ultrasonographically.

RESULTS

We included 21 patients (19 males, two females) with unilateral acute Achilles tendon rupture, in whom 42 needles (one medial and one lateral) were inserted. Correct positioning was achieved without ultrasonographic guidance for 19 (45%) needles overall, 15 of 21 (71%) medial needles, and four of 21 (19%) lateral needles. The remaining 23 needles were correctly repositioned under ultrasonographic guidance. The correct positioning rates with and without ultrasonography differed significantly for all needles (p < 0.0001) and for lateral needles (p < 0.0001) but not for medial needles (p = 0.03). Intraoperative ultrasonography confirmed tendon stump approximation in all cases.

CONCLUSION

Without imaging, 55% of needles were correctly positioned. Intraoperative ultrasonography allowed correct positioning of all needles and provided intraoperative confirmation of stump approximation.

The use of a cemented dual mobility socket to treat recurrent dislocation

BACKGROUND

The treatment of recurrent dislocation after total hip arthroplasty remains challenging. Dual mobility sockets have been associated with a low rate of dislocation but it is not known whether they are useful for treating recurrent dislocation.

QUESTIONS/PURPOSES

We therefore asked whether a cemented dual mobility socket would (1) restore hip stability following recurrent dislocation; (2) provide a pain-free and mobile hip; and (3) show durable radiographic fixation.

METHODS

We retrospectively reviewed 51 patients treated with a cemented dual mobility socket for recurrent dislocation after total hip arthroplasty between August 2002 and June 2005. The mean age at the time of the index procedure of was 71.3 years. Of the 51 patients, 47 have had complete clinical and radiographic evaluation data at a mean followup of 51.4 months (range, 25-76.3 months).

RESULTS

The cemented dual mobility socket restored complete stability of the hip in 45 of the 47 patients (96%). The mean Merle d'Aubigné hip score was 16 ± 2 at the latest followup. Radiographic analysis revealed no or radiolucent lines less than 1 mm thick located in a single acetabular zone in 43 of 47 hips (91.5%). The cumulative survival rate of the acetabular component at 72 months using revision for dislocation and/or mechanical failure as the end point was 96% ± 4% (95% confidence interval, 90%-100%).

CONCLUSIONS

A cemented dual mobility socket was able to restore hip stability in 96% of recurrent dislocating hips. However, longer-term followup is needed to ensure that dislocation and loosening rates will not increase.

Monitoring surgical performance: an application to total hip replacement

RATIONALE, AIMS AND OBJECTIVES

Inadequate surgical implantation of a hip replacement may result in decreased patient satisfaction and reduced implant survival. The objective was to monitor surgical performance in hip replacement.

METHOD

The study took place at a teaching centre. All primary total hip replacements were prospectively included in the series. For each hip replacement, intraoperative technical errors, cup and stem fixation and position, and postoperative complications were recorded. If all items rated were correct, the procedure was considered as correct. The Cumulative Sums (CUSUM) test was used to monitor the performance of the centre. A 90% proportion of successful procedures was considered as adequate performance and a 75% proportion of successful procedures was deemed as inadequate performance. Meetings were conducted to discuss the results of monitoring.

RESULTS

Eighty-three total hip replacements were monitored. Overall, 28 procedures (34%) were considered inadequate. The most potent reasons for inadequate performance were cup positioning and stem fixation. The CUSUM test signalled after the second procedure that performance was inadequate. After the first meeting, despite an improvement was seen, the CUSUM test raised an alarm indicating inadequate performance. The study was stopped after the second meeting because of funding reasons before it could be demonstrated that performance had reached the desired level.

CONCLUSION

This study has demonstrated that implementing a dedicated system to monitor surgical performance in a teaching hospital improves the quality of implantation of total hip replacements. Nonetheless, the target of ninety percent of adequate primary total hip replacement could not be reached and efforts should be continued.

Robert Merle d'Aubigné, 1900-1989

This biographical sketch of R. Merle d’Aubigné corresponds to the historic text, The Classic: Functional Results of Hip Arthroplasty with Acrylic Prosthesis, available at DOI 10.1007/s11999-008-0572-1.

ELECTRONIC SUPPLEMENTARY MATERIAL

The online version of this article (doi:10.1007/s11999-008-0571-2) contains supplementary material, which is available to authorized users.

Ipsilateral femoral autograft reconstruction after resection of a pelvic tumor

BACKGROUND

Reconstruction of bone after the resection of a pelvic tumor is challenging. The purpose of the present study was to evaluate the use of the ipsilateral femur as the graft material for reconstruction.

METHODS

We performed a retrospective review of thirteen patients with a malignant pelvic lesion who underwent resection followed by reconstruction with an ipsilateral femoral autograft and insertion of a total hip replacement. The study group included nine men and four women with a median age of fifty-one years at the time of the reconstruction. The diagnosis was chondrosarcoma in eight patients, metastasis in three, and myeloma and radiation-induced malignant disease in one each. The surviving patients were assessed functionally and radiographically; the cumulative probability of revision was estimated while taking into account competing risks.

RESULTS

The median duration of follow-up was forty-nine months. At the time of the latest follow-up, seven patients were alive and disease-free and six had died from metastatic disease. Four patients had had revision of the reconstruction, two for the treatment of mechanical complications and two for the treatment of infection. Three other patients had mechanical complications but had not had a revision. The cumulative probability of revision of the reconstruction for mechanical failure was 8% (95% confidence interval, 0% to 23%), 8% (95% confidence interval, 0% to 23%), and 16% (95% confidence interval, 0% to 39%) at one, two, and four years, respectively.

CONCLUSIONS

Although it has attendant complications consistent with pelvic tumor surgery, an ipsilateral femoral autograft reconstruction may be an option for reconstruction of pelvic discontinuity in a subgroup of patients following tumor resection. This innovative procedure requires longer-term follow-up studies.

Quantitative and individualized assessment of the learning curve using LC-CUSUM

Background

Current methods available for assessing the learning curve, such as a predefined number of procedures or direct observation by a tutor, are unsatisfactory. A new tool, the cumulative summation test for learning curve (LC-CUSUM), has been developed that allows quantitative and individual assessment of the learning curve.

Methods

Some 532 endoscopic retrograde cholangiopancreatographies (ERCPs) performed by one endoscopist over 8 years were analysed retrospectively using LC-CUSUM to assess the learning curve. The procedure was new to the endoscopist and monitored prospectively in the initial study. Success of the procedure was defined as cannulation and proper visualization of the duct(s) selected before the examination.

Results

Fifty ERCPs were considered unsuccessful. There was a gradual improvement in performance over time from a success rate of 82·0 per cent for the first 100 procedures to 96·1 per cent for the last 129 procedures. The LC-CUSUM signalled at the 79th procedure, indicating that sufficient evidence had accumulated to prove that the endoscopist was competent.

Conclusion

LC-CUSUM allows quantitative monitoring of individual performance during the learning process.

Function, disability, and health-related quality of life after allograft-prosthesis composite reconstructions of the proximal femur

BACKGROUND

Factors affecting function, disability and health-related quality of life after allograft-prosthesis composite reconstructions have been poorly studied.

METHODS

Retrospective study of eighteen patients who underwent reconstruction with proximal femoral allograft-prosthesis composites and answered questionnaires to assess hip function (Postel and Merle d'Aubigné, self-reported Harris Hip Score), disability (Toronto Extremity Salvage Score), and health-related quality of life (SF-36).

RESULTS

The median Toronto Extremity Salvage Score was 76 (IQR: 48-85), the median self-reported Harris Hip Score was 90 (IQR: 48-95) and the median Postel and Merle d'Aubigné score was 17 (IQR: 12-17). Older age, female gender, and presentation with a pathologic fracture were associated with increased disability and poorest function. The median Physical Component Summary score was 44 (IQR: 39-45) and Mental Component Summary scores were 49 (IQR: 46-56). Male gender and recurrence of disease were associated with poorer health-related quality of life. There was a high degree of correlation between function, disability scores and Physical Component Summary score.

CONCLUSIONS

Patients' characteristics at presentation such as age, gender, and occurrence of a pathologic fracture play an important role in determining disability, function, and health-related quality of life after allograft-prosthesis composite reconstruction of the proximal femur.

Quality control of surgical and interventional procedures: a review of the CUSUM

BACKGROUND

The report of the CUSUM across surgical and interventional procedures has spawned a fair confusion in the literature.

AIM

To assess the use of the CUSUM and to clarify its utilisation in the perspective of future studies. Nature of the study: Retrospective review.

METHODS

A systematic literature search of Medline was carried out. From each article, data regarding the design of the study, the specialty, the performance criterion, the unit under control, the methodology and the model of the CUSUM used, the use of a graph, the use of a test and the type of test applied were retrieved.

RESULTS

31 studies were found relevant. The design was mainly retrospective for the analysis of the learning curve. The main performance criteria under control were morbidity, mortality and success of the procedure. A graph was plotted in all studies as a CUSUM plot or as cumulative sums of non-negative values. A test was used in 17 studies. Mislabelling of the plot and the test, and misuse of control limits were the most commonly reported mistakes.

CONCLUSION

The CUSUM tool is not yet properly reported in the surgical literature. Therefore, reporting of the CUSUM should be clarified and standardised before its use widens.

ACL reconstruction: a meta-analysis of functional scores

From individual randomized studies, it is unclear whether patellar tendon grafts or hamstring tendon grafts yield the best functional results after ACL reconstruction. Therefore, we performed a meta-analysis to provide quantitative data to compare patellar with hamstring grafts after ACL reconstruction with regard to knee function. We searched computerized databases for randomized controlled trials reporting one of the following outcomes related to function: final overall International Knee Documentation Committee score and return to preinjury level of activity. Studies were abstracted independently by two reviewers. Random effect models were used to pool the data. Fourteen trials (1263 patients) met the inclusion criteria. We found no difference in final overall International Knee Documentation Committee score or in the number of patients returning to full activity after patellar and hamstring graft reconstruction. Relative risk was 0.90 for final overall International Knee Documentation Committee Class A and 0.94 for return to preinjury level of activity in favor of patellar grafts. Quantitative interaction tests on the effect of treatment based on study quality, randomization status, number of strands used, and length of followup were non significant. At last followup, only 41% and 33% of patients, respectively, had patellar and hamstring grafts reconstructed reported as normal based on the final overall International Knee Documentation Committee score.

Bone-patellar tendon-bone autografts versus hamstring autografts for reconstruction of anterior cruciate ligament: meta-analysis

OBJECTIVES

To compare bone-patellar tendon-bone autografts with hamstring autografts for reconstruction of the anterior cruciate ligament.

DATA SOURCES

Medline, WebSPIRS, Science Citation Index, Current Contents databases, and Cochrane Central Register of Controlled Trials. Review methods All randomised controlled trials reporting one or more outcome related to stability (instrumented measurement of knee laxity, Lachman test, or pivot shift test) and morbidity (anterior knee pain, kneeling test, loss of extension, or graft failure). Study quality was assessed by using a 5 point scale. Random effect models were used to pool the data. Heterogeneity in the effect of treatment was tested on the basis of study quality, randomisation status, and number of tendon strands used.

RESULTS

24 trials of 18 cohorts (1512 patients) met the inclusion criteria. Study quality was poor for nine studies and fair for nine studies. The weighted mean difference of the instrumented measurement of knee laxity was 0.36 (95% confidence interval 0.01 to 0.71; P = 0.04). Relative risk of a positive Lachman test was 1.22 (1.01 to 1.47; P = 0.04), of anterior knee pain 0.57 (0.44 to 0.74; P < 0.0001), of a positive kneeling test 0.26 (0.14 to 0.48; P < 0.0001), and of loss of extension 0.52 (0.34 to 0.80; P = 0.003). Other results were not significant.

CONCLUSION

Morbidity was lower for hamstring autografts than for patellar tendon autografts. Evidence that patellar tendon autografts offer better stability was weak. The poor quality of the studies calls into question the robustness of the analyses.