Traumatic Patellar Tendon Rupture Repair Using Synthetic Ligament Augmentation.

Rupture of the patellar tendon is an infrequent pathology, and surgical repair with nonabsorbable sutures is the gold standard for management. Many surgeons augment the repair using one of many proposed methods: cerclage wires, Dall-Miles cables, autologous hamstring grafts, and tendon allografts. In this study, we propose the augmentation of patellar tendon repair using an artificial ligament. The questions to be assessed in this study are as follows: (1) measurement of functional results 1 year after surgery using the Lysholm score and (2) the incidence of both rerupture, and surgical complications within the first year postsurgery, the median knee range of motion at 3 months and 1-year postsurgery, patient satisfaction, and postsurgery patellar height, measured using the Caton-Deschamps Index. In our center, we performed 30 suture repairs of traumatic patellar tendon ruptures between 2015 and 2016. Tendon repair was always augmented using an artificial ligament (LT60, Orthomed). The results were evaluated 1 year after surgery. The 1-year postsurgery median Lysholm score was 96 (first quartile-third quartile [Q1-Q3]: 95-100). None of the following complications were reported: second surgery for any reason, new rupture, and superficial or deep infection. Radiological analysis showed a median Caton Index of 1 (Q1-Q3: 0.9-1) postsurgery. Excellent Lysholm scores were observed 1 year after synthetic ligament augmentation of patellar tendon sutures, with a low rate of complications compared with published studies.

Neither pre-operative education or a minimally invasive procedure have any influence on the recovery time after total hip replacement.

PURPOSE: The purpose of this study was to evaluate pre-operative education versus no education and mini-invasive surgery versus standard surgery to reach complete independence. METHODS: We conducted a four-arm randomized controlled trial of 209 patients. The primary outcome criterion was the time to reach complete functional independence. Secondary outcomes included the operative time, the estimated total blood loss, the pain level, the dose of morphine, and the time to discharge. RESULTS: There was no significant effect of either education (HR: 1.1; P = 0.77) or mini-invasive surgery (HR: 1.0; 95 %; P = 0.96) on the time to reach complete independence. The mini-invasive surgery group significantly reduced the total estimated blood loss (P = 0.0035) and decreased the dose of morphine necessary for titration in the recovery (P = 0.035). CONCLUSIONS: Neither pre-operative education nor mini-invasive surgery reduces the time to reach complete functional independence. Mini-invasive surgery significantly reduces blood loss and the need for morphine consumption.

Limited arthrodesis of the wrist for treatment of giant cell tumor of the distal radius.

PURPOSE: To present the functional results of a technique of radiocarpal arthrodesis and reconstruction with a structural nonvascularized autologous bone graft after en bloc resection of giant cell tumors of the distal radius. METHODS: A total of 13 patients with a mean age of 37 years with aggressive giant cell tumor (Campanacci grade III) of distal radius were managed with en bloc resection and reconstruction with a structural nonvascularized bone graft. The primary outcome measure was the disability evaluated by the Musculoskeletal Tumor Society rating score of limb salvage. Secondary outcomes included survival of the reconstruction measured from the date of the operation to revision procedure for any reason (mechanical, infectious, or oncologic). Other outcomes included active wrist motion and ability to resume work. RESULTS: Mean follow-up period was 6 years (range, 2-14 y). The median arc of motion at the midcarpal joint was 40°, median wrist flexion was 20°, and median extension was 10°. The median Musculoskeletal Tumor Society score based on the analysis of factors pertinent to the patient as a whole (pain, functional activities, and emotional acceptance) and specific to the upper limb (positioning of the hand, manual dexterity, and lifting ability) was 86%. Five patients underwent a second surgical procedure. The cumulative probability of reoperation for mechanical reason was 31% at similar follow-up times at 2, 5, and 10 years. CONCLUSIONS: This technique provided a stable wrist and partially restored wrist motion with limited pain. However, further surgical procedures may be necessary to reach this goal. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Is superolateral Hoffa fat pad edema a consequence of impingement between lateral femoral condyle and patellar ligament?

PURPOSE: To evaluate whether knee extensor mechanism features are associated with superolateral Hoffa fat pad edema at magnetic resonance imaging. MATERIALS AND METHODS: Institutional review board approval and written consent from all patients were obtained. Patients with superolateral Hoffa fat pad edema (n = 30) and a control group without edema of the fat pad (n = 60) were evaluated prospectively with magnetic resonance (MR) imaging. Demographic data and extensor mechanism features were compared, including trochlear depth, lateral trochlear inclination, patellar tilt angle, patellar height ratio, distance between patellar ligament and lateral trochlear facet, distance from the tibial tubercle to the trochlear groove, patellar facet asymmetry, and patellar ligament abnormalities. RESULTS: The following variables were associated with superolateral Hoffa fat pad edema in the multivariable models: patellar height ratio (P = .023), shortest distance between patellar ligament and lateral trochlear facet (P < .001), and distance from the tibial tubercle to the trochlear groove (P = .046). Of all demographic and degenerative variables, only age was significantly associated, with younger patients more likely to have superolateral Hoffa fat pad edema (P < .009). CONCLUSION: A high-riding patella, a short distance between the patellar ligament and the lateral trochlear facet, and an increased distance from the tibial tubercle to the trochlear groove are associated with superolateral Hoffa fat pad edema at MR imaging. These results are suggestive of impingement between the lateral femoral condyle and the posterior aspect of the patellar ligament in these patients.

P value and the theory of hypothesis testing: an explanation for new researchers.

In the 1920s, Ronald Fisher developed the theory behind the p value and Jerzy Neyman and Egon Pearson developed the theory of hypothesis testing. These distinct theories have provided researchers important quantitative tools to confirm or refute their hypotheses. The p value is the probability to obtain an effect equal to or more extreme than the one observed presuming the null hypothesis of no effect is true; it gives researchers a measure of the strength of evidence against the null hypothesis. As commonly used, investigators will select a threshold p value below which they will reject the null hypothesis. The theory of hypothesis testing allows researchers to reject a null hypothesis in favor of an alternative hypothesis of some effect. As commonly used, investigators choose Type I error (rejecting the null hypothesis when it is true) and Type II error (accepting the null hypothesis when it is false) levels and determine some critical region. If the test statistic falls into that critical region, the null hypothesis is rejected in favor of the alternative hypothesis. Despite similarities between the two, the p value and the theory of hypothesis testing are different theories that often are misunderstood and confused, leading researchers to improper conclusions. Perhaps the most common misconception is to consider the p value as the probability that the null hypothesis is true rather than the probability of obtaining the difference observed, or one that is more extreme, considering the null is true. Another concern is the risk that an important proportion of statistically significant results are falsely significant. Researchers should have a minimum understanding of these two theories so that they are better able to plan, conduct, interpret, and report scientific experiments.

Patellar tendon versus hamstring tendon autografts for reconstructing the anterior cruciate ligament: a meta-analysis based on individual patient data.

BACKGROUND: The best means of ensuring knee stability after anterior cruciate ligament (ACL) reconstruction remains a core debate in sports medicine. HYPOTHESIS: There is no difference between ACL reconstruction with patellar tendon or hamstring tendon autografts with regard to postoperative knee laxity and instability. STUDY DESIGN: Meta-analysis of individual patient data. METHODS: Pooled analysis of individual patient data from 6 published randomized clinical trials included 423 patients with symptomatic unilateral anterior cruciate ligament injury randomly assigned to reconstruction with patellar tendon or hamstring tendon autograft. Knee instability, defined as a positive pivot-shift test result, was the primary outcome, and knee laxity, defined as a positive Lachman test result, was the secondary outcome. Odds ratios were computed before and after adjustment for potential confounders and trial effect. Regression analyses were performed to look for effects of covariates on outcomes, and mixed-effects models were used to account for a trial effect. Sensitivity analyses were conducted to explore the effects of missing data and excluding each trial. RESULTS: Anterior cruciate ligament reconstruction with patellar tendon autograft was significantly associated with a decreased risk of a positive pivot-shift test result (adjusted odds ratio, 0.46; 95% confidence interval, 0.24-0.86; P = .016). The risk of having a positive Lachman test result was not significantly different between the 2 groups. The estimated treatment effect was not substantially changed by differences in handling missing data or exclusion of any of the trials. A positive pivot-shift test result was more common in female (P = .003) and younger patients (P = .017). CONCLUSION: Postoperative knee instability was less common after ACL reconstruction with patellar tendon autograft than with hamstring tendon autograft.

Case report: reconstruction of a 16-cm diaphyseal defect after Ewing's resection in a child.

Numerous options exist for intercalary segmental reconstruction after bone tumor resection. We present the extension of a recently developed surgical two-stage technique that involves insertion of a cement spacer, induction of a membrane, and reconstruction of the defect with cancellous and cortical bone autograft in a 12-year-old child. The boy was referred to our center for treatment of a right femoral diaphyseal Ewing's sarcoma. The first stage involved resection of the tumor and reconstruction with a locked intramedullary nail and a polymethylmethacrylate cement spacer. Seven months after the initial procedure during which adjuvant chemotherapy was given, the second-stage procedure was performed. The cement was removed and cancellous and cortical bone autograft was grafted in the membrane created around the cement spacer. Touchdown weightbearing was allowed immediately, partial weightbearing was resumed 6 weeks after the operation, and full weightbearing was allowed 4 months later. Successive plain radiographs showed rapid integration of the autograft to the host bone with bone union and cortical reconstitution. The principle of the induced membrane reconstruction seems applicable to intercalary segmental reconstruction after bone tumor resection in children.

Statistics in brief: the importance of sample size in the planning and interpretation of medical research.

The increasing volume of research by the medical community often leads to increasing numbers of contradictory findings and conclusions. Although the differences observed may represent true differences, the results also may differ because of sampling variability as all studies are performed on a limited number of specimens or patients. When planning a study reporting differences among groups of patients or describing some variable in a single group, sample size should be considered because it allows the researcher to control for the risk of reporting a false-negative finding (Type II error) or to estimate the precision his or her experiment will yield. Equally important, readers of medical journals should understand sample size because such understanding is essential to interpret the relevance of a finding with regard to their own patients. At the time of planning, the investigator must establish (1) a justifiable level of statistical significance, (2) the chances of detecting a difference of given magnitude between the groups compared, ie, the power, (3) this targeted difference (ie, effect size), and (4) the variability of the data (for quantitative data). We believe correct planning of experiments is an ethical issue of concern to the entire community.

Competing events influence estimated survival probability: when is Kaplan-Meier analysis appropriate?

The Kaplan-Meier estimator is the current method for estimating the probability of an event to occur with time in orthopaedics. However, the Kaplan-Meier estimator was designed to estimate the probability of an event that eventually will occur for all patients, ie, death, and this does not hold for other outcomes. For example, not all patients will experience hip arthroplasty loosening because some may die first, and some may have their implant removed to treat infection or recurrent hip dislocation. Such events that preclude the observation of the event of interest are called competing events. We suggest the Kaplan-Meier estimator is inappropriate in the presence of competing events and show that it overestimates the probability of the event of interest to occur with time. The cumulative incidence estimator is an alternative approach to Kaplan-Meier in situations where competing risks are likely. Three common situations include revision for implant loosening in the long-term followup of arthroplasties or implant failure in the context of limb-salvage surgery or femoral neck fracture.

Allograft-prosthesis composites after bone tumor resection at the proximal tibia.

The survival of irradiated allograft-prosthesis composites at the proximal tibia is mostly unknown. However, allograft-prosthesis composites have proved beneficial at other reconstruction sites. We presumed allograft-prosthesis composites at the proximal tibia would improve survival and facilitate reattachment of the extensor mechanism compared with that of conventional (megaprostheses) reconstructions. We retrospectively reviewed 26 patients who underwent resection of proximal tibia tumors followed by reconstruction with allo-graft-prosthesis composites. Patients received Guepar massive custom-made fully constrained prostheses. Allografts were sterilized with gamma radiation, and the stems were cemented into the allograft and host bone. The minimum followup was 6 months (median, 128 months; range, 6-195 months). Fourteen patients had one or more components removed. The median allograft-prosthesis composite survival was 102 months (95% confidence interval, 64.2-infinity). Of the 26 allografts, seven fractured, six showed signs of partial resorption, and six had infections develop. Seven allografts showed signs of fusion with the host bone. Six extensor mechanism reconstructions failed. Allograft-prosthesis composites sterilized by gamma radiation yielded poor results for proximal tibial reconstruction as complications and failures were common. We do not recommend irradiated allograft-prosthesis composites for proximal tibia reconstruction.