Some years ago, we moved away from calling hip dysplasia “congenital” and started using the term “developmental dysplasia of the hip” (DDH). Indeed, it is developmental. As a surgeon specializing in pediatric orthopaedics and hip preservation, I see not only infants when DDH is of potential concern but also young adults with more mature manifestations of hip dysplasia not previously diagnosed or treated.
Screening protocols have successfully helped in the early identification of DDH and dislocation, but what is the likelihood that infants with risk factors for dysplasia but normal ultrasound results will go on to experience DDH in childhood? And which risk factors are predictive?
In a recent report in JBJS Open Access, Humphry et al. provide new insight into these challenging questions. This study from the UK included 1,053 children from a cohort of 2,191 children who had been assessed as newborns and had at least 1 of 9 perinatal risk factors for DDH. All had undergone ultrasound at a mean of 8 weeks and were followed clinically.
The mean age of the children in the current study was 4.4 years (range, 2.0 to 6.6 years). Thirty-seven of the participants had been treated for DDH in the postnatal period, predominantly with a harness.
Assessing the acetabular index (AI) on pelvic radiographs, the authors found that:
- 27 of the children had “severe” hip dysplasia (an AI of >2 standard deviations above age and sex reference values). Girls were more likely to have this outcome. Only 3 of the 27 received treatment for DDH in infancy.
- 146 (13.9%) of the children had an AI of >20°, only 12 of whom had been treated during infancy; 92% had no prior diagnosis of DDH. On multivariate analysis, female sex and breech presentation at birth were significantly predictive of this “mild” dysplasia (breech presentation demonstrated a nearly twofold increased odds of an AI of >20° at ≥3 years of age), while first-born status had a protective effect.
The findings of this study lend support to radiographic monitoring later in childhood for patients with risk factors such as breech positioning at birth. While the exact algorithm of ultrasound and radiographic workup still needs to be elucidated, it appears that a “normal” ultrasound in infancy does not necessarily rule out the development of hip dysplasia in children with select risk factors.
Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media
OrthoBuzz occasionally receives posts from guest bloggers. In response to a recent article in Ultrasound in Medicine and Biology by Bekhet et al., this commentary comes from Christopher Dy, MD, MPH.
In their study from Cairo, Egypt, Bekhet et al. report their experience using ultrasound (US) to examine tendon integrity in the setting of suspected flexor tendon injury. A single musculoskeletal radiologist performed diagnostic US in 35 patients with trauma to the ventral surface of the hand or wrist; a total of 50 tendons were evaluated, with zone-II injuries being the most common.
US correctly identified all complete tendon disruptions, with no false positive or false negative results. US identified partial tendon injuries with 98% accuracy, with 1 false positive result and no false negatives. In comparison, clinical examination alone had a diagnostic accuracy of 88%. The diagnostic performance of US in this study is impressive, and suggests that US may have a role in the diagnostic workup of patients with suspected flexor tendon injury.
While many surgeons still rely on physical examination, it is clear that clinical assessment alone is imperfect. An accurate, objective diagnostic test is desirable for determining the need for (and extent of) surgical treatment as well as in counseling patients. MRI has been suggested to fill this role, but it can be expensive and time-consuming. US is a natural alternative, but its usage in most practice settings (including North America) has been limited because of its operator-dependent nature. That is a key acknowledgment made by the authors of this study, which limits the generalizability and impact of their findings. As only 1 highly specialized radiologist performed the US examinations in the study, it is unclear whether US performed by a less-experienced sonographer would provide the level of detail needed to directly affect clinical management.
Further validation studies (both within the authors’ institution as well as in other centers) would provide important information to determine the utility of US in accurately diagnosing the location and extent of flexor tendon injuries.
In my practice, if there is doubt regarding the integrity of a flexor tendon, I have used US performed by a musculoskeletal (MSK) radiologist or a US-trained physiatrist to provide diagnostic clarity. Admittedly, if the US results do not match my clinical impression, I will either order an MRI or discuss surgical exploration with the patient. This bias in my decision-making process clearly demonstrates my belief that further work is needed to show that US can be used accurately and reliably. While the findings of Bekhet et al. are intriguing, the single-sonographer limitation leads me to question the external validity of their findings. Because of this, the findings of this study are not practice-changing. But I hope to be proven wrong!
Christopher Dy, MD, MPH is a hand and wrist surgeon, an assistant professor of orthopaedic surgery at Washington University School of Medicine in St. Louis, and a member of the JBJS Social Media Advisory Board.
Every month, JBJS publishes a review of the most pertinent and impactful studies published in the orthopaedic literature during the previous year in 13 subspecialties. Click here for a collection of OrthoBuzz summaries of these “What’s New” articles. This month, author Christopher J. Dy, MD, MPH selected the 5 most clinically compelling findings from the more than 50 studies summarized in the March 18, 2020 “What’s New in Hand and Wrist Surgery.”
—A retrospective case series investigating 3 treatments for scaphoid nonunion among >100 patients1 found the following:
- Those receiving iliac crest bone graft (n=31), most of whom had carpal collapse with preserved proximal pole vascularity, had a union rate of 71%, a time-to-union of 19 weeks, and a reoperation rate of 23%.
- Those receiving an intercompartmental supraretinacular artery flap (n=33), most of whom had osteonecrosis of the proximal pole and half of whom had carpal collapse, had a union rate of 79%, a time-to-union of 26 weeks, and a reoperation rate of 12%.
- Those receiving a free vascularized medial femoral condyle flap (n=45), most of whom had carpal collapse, osteonecrosis, and prior surgery, had a union rate of 89%, a time-to-union of 16 weeks, and a reoperation rate of 16%.
—Among 13 patients with scaphoid nonunion and osteonecrosis who were treated with cancellous autograft packing and volar-plate fixation,2 there was 100% fracture union, with most achieving union within 18 weeks. However, preoperative carpal-collapse rates were not reported, making it difficult to assess the role of this procedure.
Finger Replantation: Financial Issues
—The frequency and success rates of finger replantation have been decreasing in the US. A review of physician reimbursement for these procedures3 found that replantation has lower reimbursement per work relative value unit (RVU) than many other common hand surgeries, including revision amputation, carpal tunnel release, and trigger finger surgery. This “relative devaluation” may help explain the decline in frequency and success of finger replantation.
Socioeconomics of Carpal Tunnel Syndrome
—Among patients seeking treatment for carpal tunnel syndrome, those from areas of “increased social deprivation” had worse physical function, pain interference, anxiety, and depression than patients from more affluent areas.4
Cubital Tunnel Syndrome
—A study of preoperative dynamic ultrasound in patients with cubital syndrome5 found that ultrasound was far more reliable than preoperative clinical examinations in predicting ulnar nerve stability within the cubital tunnel (88% match with intraoperative findings vs 12% match, respectively). Preoperative ultrasound may therefore help surgeons counsel patients about the possible need for nerve transposition.
- Aibinder WR, Wagner ER, Bishop AT, Shin AY. Bone grafting for scaphoid nonunions: is free vascularized bone grafting superior for scaphoid nonunion?Hand (N Y). 2019 Mar;14(2):217-22. Epub 2017 Oct 27.
- Putnam JG, DiGiovanni RM, Mitchell SM, Castañeda P, Edwards SG. Plate fixation with cancellous graft for scaphoid nonunion with avascular necrosis. J Hand Surg Am.2019 Apr;44(4):339.e1-7. Epub 2018 Aug 10.
- Hooper RC, Sterbenz JM, Zhong L, Chung KC. An in-depth review of physician reimbursement for digit and thumb replantation. J Hand Surg Am.2019 Jun;44(6):443-53. Epub 2019 Apr 17.
- Wright MA, Beleckas CM, Calfee RP. Mental and physical health disparities in patients with carpal tunnel syndrome living with high levels of social deprivation. J Hand Surg Am.2019 Apr;44(4):335.e1-9. Epub 2018 Jun 23.
- Rutter M, Grandizio LC, Malone WJ, Klena JC. The use of preoperative dynamic ultrasound to predict ulnar nerve stability following in situ decompression for cubital tunnel syndrome. J Hand Surg Am.2019 Jan;44(1):35-8. Epub 2018 Nov 27.
Orthopaedic surgeons work with radiation in some capacity almost every day. We would struggle to provide quality patient care if it were not for the many benefits that radiographic images provide us. But the more we are exposed to something, the less we tend to think about it. For example, how often do we discuss the risks of radiation exposure with our patients—especially those who are exposed to a large amount of it after an acute traumatic injury?
The article by Howard et al. in the August 7, 2019 issue of JBJS strongly suggests that polytrauma patients need to better understand the risks associated with radiation exposure as they progress through treatment of their injuries. The authors evaluated the cumulative 12-month postinjury radiation exposure received by almost 2,400 trauma patients who had an Injury Severity Score of 16+ upon admission. Those patients received a median radiation dose (not counting fluoroscopy) of 18.46 mSv, and their mean radiation exposure was 30.45 mSv. These median-versus-mean data indicate that a small subset of patients received substantially more radiation than others, and in fact, 4.8% of the cohort was exposed to ≥100 mSv of radiation. To put these amounts in context, the average human in the UK (where this study was performed) is exposed to about 2 mSv of background radiation per year, and there is good evidence suggesting that carcinogenesis risk increases with acute radiation doses exceeding 50 mSv.
Based on mathematical models (actual occurrences of cancer were not tracked), the authors conclude that for these patients, the median risk of fatal carcinogenesis as a result of medical radiation following injury was 3.4%. In other terms, 85 of these patients would be expected to develop cancer as a result of medical imaging—which struck me as a startling estimate.
So what are we to do? In a Commentary accompanying this study, David A. Rubin, MD, FACR offers some practical suggestions for reducing unnecessary radiation exposure. I personally feel that because the radiation associated with CT scans and radiographs can be, quite literally, life-saving for patients who have sustained traumatic injuries, increasing the chance that patients develop cancer later in life in order to save their life now is a good risk-benefit proposition. But the findings from this study should make us think twice about which imaging tests we order, and they should encourage us to help patients better understand the risks involved.
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media
In the setting of rotator cuff injuries, higher degrees of fatty infiltration into cuff muscles are positively correlated with higher repair failure rates and worse clinical outcomes. MRI continues to be the gold standard imaging modality for evaluating fatty infiltration of the rotator cuff, but ultrasound represents another viable modality for that assessment—at considerably lower cost. Such is the conclusion of Tenbrunsel et al. in a recent issue of JBJS Reviews.
The authors reviewed 32 studies that investigated imaging modalities used to assess fatty infiltration and fatty atrophy. They found that grading fatty infiltration using ultrasound correlated well with grading using MRI. However, the authors identified difficulties distinguishing severe from moderate fatty infiltration on ultrasound, but they added that discerning mild from moderate fatty infiltration is more important clinically. Tenbrunsel et al. also mention sonoelastography, which measures tissue elasticity and can also be used to help determine the severity of fatty atrophy of the rotator cuff.
Overall, the trade-off between MRI and ultrasound comes down to higher precision with the former and lower cost with the latter.
For more information about JBJS Reviews, watch this video featuring JBJS Editor-in-Chief Dr. Marc Swiontkowski.