HSS Journal®: The Musculoskeletal Journal of Hospital for Special Surgery

Patella alta is common in children with cerebral palsy (CP), often resulting from quadriceps spasticity and tendon elongation. In typically developing children, patella alta is linked to trochlear dysplasia and instability. Whether these associations exist in CP, and how they vary with age and functional ability, has not been established.

We sought to determine whether patella alta is associated with alterations in trochlear morphology in ambulatory children with CP and to evaluate the influence of age and functional severity.

We conducted a retrospective study of pediatric patients under the age of 18 diagnosed with hemiplegic or diplegic CP. We included patients classified as Gross Motor Function Classification System levels I to III to ensure relative ambulatory function and minimize confounding due to severe joint contractures. Inclusion criteria included patients who had had a lateral radiograph of the knee and axial computed tomography scans of the distal femur and proximal tibia showing the anterior tibial tuberosity. Eligible patients were identified through a comprehensive search of the institutional electronic medical record system between 2016 and 2024.

Of the 164 patients identified, 31 were included based on available imaging suitable for the assessment of both patellar height and trochlear morphology; 6 of these patients were excluded due to poor image quality, resulting in a final cohort of 25 patients and 48 limbs. Patella alta was identified in 17 knees (35.4%). No differences in trochlear morphology were observed between groups or across functional levels. In both groups, older age correlated with features of physiologic trochlear development, including increased trochlear groove depth and narrower sulcus angle. in patients with patella alta, age also correlated with greater tibial tubercle to trochlear groove (TT-TG) distance.

Patella alta was not associated with trochlear dysplasia in ambulatory children with CP. However, its persistent presence may alter patellofemoral alignment through age-related increases in TT-TG distance, contributing to pain or instability, highlighting the need for longitudinal studies and early recognition in clinical care.

Level IV, Retrospective Prognostic Study

“Rice body” describes the gross appearance of hyperplastic synovial villi that develop into rice-like fibrinous loose bodies. Rice bodies have historically been associated with tuberculosis and inflammatory arthritis, but no retrospective studies have correlated their magnetic resonance imaging (MRI) appearances to histology or to the underlying diagnoses.

We sought to correlate the appearance on MRI of rice body-like particles with histology and describe the associated diagnoses.

We conducted a retrospective cross-sectional study of MRI reports in our institutional imaging database in which a radiologist described “rice bodies.” The search was performed by a keyword search for “rice,” ultimately yielding a total of 100 patients between June 1992 and July 2022. Patients were excluded if their MRI was not available for retrospective review or if there was insufficient follow-up to establish a clear underlying diagnosis. Cases were included if the MRI finding of rice bodies was confirmed by retrospective review of the images and there was clinical follow-up or surgery with histology establishing the underlying diagnosis.

Of the 52 patients who met inclusion criteria and were enrolled in our retrospective study, 37% (19/52) had prior surgery, 73% (14/19) being arthroplasty. Diagnoses associated with rice body-like particles on MRI were inflammatory arthritis (52%; 27/52), infection (25%; 13/52), synovial chondromatosis (8%; 4/52), osteoarthritis (6%; 3/52), bursitis (6%; 3/52), and adverse local tissue reaction (4%; 2/52). Among 13 infections, only 1 was mycobacterial while 46% (6/13) were staphylococcal and 31% (4/13) were culture-negative. In the presence of arthroplasty, rice body-like particles were associated with infection in 71% (10/14), followed by adverse local tissue reaction (14%; 2/14), 46% (24/52) underwent surgery after MRI, and 45% (10/22) had rice bodies confirmed on histology.

Our retrospective findings suggest that rice body-like synovial particles on MRI are not specific to tuberculosis and inflammatory arthritis. Other diagnoses may also be considered, particularly nonmycobacterial infection when there is an arthroplasty.

Level IV: retrospective cross-sectional study.

Evaluating physical activity in children is crucial for determining functional limitations and promoting healthy growth. The Hospital for Special Surgery Pediatric Functional Activity Brief Scale (HSS Pedi-FABS) is a valid, concise tool that assesses activity levels of children and adolescents participating in sports. There is currently no validated Turkish version.

We sought to (1) translate and cross-culturally adapt the HSS Pedi-FABS into Turkish and (2) evaluate the scale’s psychometric properties in a Turkish pediatric and adolescent population.

The HSS Pedi-FABS was translated and culturally adapted following established guidelines. Physically active, healthy, and Turkish-speaking children and adolescents aged 8 to 17 years were included in the study. The exclusion criteria were as follows: (1) orthopedic/neurological conditions limiting functional activity, (2) language difficulties that could limit comprehension, (3) cognitive impairments, (4) illiteracy, (5) major organ failure, (6) malignancy, and (7) refusal to participate. Psychometric evaluation included internal consistency (Cronbach’s α), test-retest (t1-t2) reliability (intraclass correlation coefficient), construct validity (correlation with existing physical activity questionnaires), and floor/ceiling effects.

Fifty-five participants were included in the study. The Turkish version of the HSS Pedi-FABS (Turkish HSS Pedi-FABS) showed good internal and excellent test-retest reliability. Construct validity was demonstrated with strong correlations between the Turkish questionnaire and comparator instruments. No floor or ceiling effects were found as the minimum score was observed in <15% of participants (5.5% at t1) and the maximum score was not observed.

The Turkish HSS Pedi-FABS is a valid and reliable instrument for assessing physical activity in healthy children and adolescents. It can be used for both clinical and research purposes.

Level II: validation study.

Large language models (LLMs), an artificial intelligence tool, have become widely available and used by patients and members of the general public to answer health care questions.

We sought to understand whether currently available LLMs can recommend an appropriate total knee arthroplasty (TKA) surgeon when prompted.

We used 3 widely available LLMs (ChatGPT, Gemini, and DeepSeek) to conduct searches for a TKA surgeon, with 1 of 4 home cities specified (Lynchburg, VA; Trumbull, CT; Chicago, IL; and New York, NY). The first prompt posed was (1) “I was told by my primary care provider that I need a knee replacement, I live in (city, state), who would you recommend that I see?” Once the list of surgeons was elicited, the LLM was prompted: (2) “Why did you recommend this (these) surgeon(s)?”; (3) “Where did you get your information about this (these) surgeon(s)?”; and (4) “How do I get in contact with this (these) surgeon(s)?” Recommendations were considered appropriate if the surgeon routinely performed TKA and was actively practicing in the area. Descriptive statistics and Fisher’s exact tests were used to summarize findings.

Across the 3 LLMs, 49 of the 74 (66%) recommendations were deemed appropriate, although this varied by model: Gemini (26/30, 87%), ChatGPT (14/19, 74%), and DeepSeek (9/25, 36%). Of the inappropriate responses, 6 of the surgeons were out of area, 13 were not performing TKA, and 6 were hallucinated names. When asked for rationales for the recommendations, LLMs most commonly cited hospital and practice Web sites and patient reviews, which tended to favor surgeons with longer local practice tenure. Of the 74 contact details provided, only 17 (23%) were accurate, with significant variation among models: ChatGPT (13/19, 79%), DeepSeek (2/25, 8%), and Gemini (2/30, 7%).

While LLMs show potential in identifying TKA surgeons, the 3 LLMs we tested varied in their ability to validate surgeon expertise and provide reliable contact information. Further research may be necessary to elucidate the criteria by which LLMs recommend surgeons.

Avascular necrosis (AVN) of the bone may result in severe pain, and patients with AVN and their families may seek out information about the condition. With the rise of ChatGPT, AVN patients and families may turn to this chatbot with questions.

We sought to explore expert clinicians’ perceptions of the quality of ChatGPT’s responses to frequently asked parent questions about AVN in children. Secondary aims of this study were to assess provider perceptions of ChatGPT and AVN parental education and to evaluate the readability of ChatGPT responses.

We conducted a cross-sectional survey study of 9 pediatric orthopedic surgeons, oncologists, and advanced practice providers with expertise in the clinical management of AVN. Fifteen common questions parents ask about AVN were posed to ChatGPT, preceded by the following prompt: “Please answer the following parent question relating to avascular necrosis. Please give me a response at or below a sixth-grade reading level: [Question].” The answers were evaluated by participants using a 4-point Likert scale. ChatGPT responses were also assessed using the following readability scores: Flesch-Kincaid Grade Level, Gunning Fog index, and Flesch Reading Ease. In addition, the survey included 4 questions developed to gather overall provider perceptions.

Providers deemed answers to all 15 questions as at least satisfactory, requiring minimal clarification on average. Yet only 3 ChatGPT responses (20%) were at or below a sixth-grade reading level, as prompted. The average Flesch-Kincaid Grade Level was 6.94, and the average Gunning Fog Index was 9.22, suggesting the responses reflect a reading level between approximately seventh grade and early high school. A majority of providers agreed that these responses would be sufficient for most parents (56%) and that the information was at the appropriate reading level (100%).

The findings of this small survey study suggest that ChatGPT’s responses to common parent questions about AVN were satisfactory, requiring minimal clarification. ChatGPT has the potential to serve as a resource for orthopedic patients and family education, though concerns remain.

Acute compartment syndrome (ACS) is a limb-threatening complication of pediatric tibial tubercle fractures. Despite its severity, the incidence of ACS in pediatric cases has been largely unexplored.

We sought to examine the incidence and risk factors of ACS and associated fasciotomies in pediatric patients with tibial tubercle fractures.

We conducted a retrospective cohort study using data from the Pediatric Health Information System, a comprehensive inpatient and outpatient nationwide database. Inclusion criteria specified patients 18 years of age or younger with tibial tubercle fracture (International Classification of Disease, 10th Revision (ICD-10) diagnosis code, S82.151-156) between October 1, 2015, and June 30, 2023. Exclusion criteria were patients with a positive hematologic or immunologic flag and patients with a positive congenital or genetic defect flag. Patients with tibial tubercle fractures were stratified into 3 categories: (1) patients with a diagnosis code for ACS and/or a fasciotomy procedure code; (2) patients with a diagnosis code for ACS and a fasciotomy code; and (3) patients exclusively with a fasciotomy procedure code.

Of the 6830 included patients with tibial tubercle fractures, 4% had a code for ACS and/or fasciotomy, 1% had a code for ACS and a procedure code for fasciotomy, and 2.9% had a code for fasciotomy only. Univariate analysis revealed that older and male patients had higher rates of ACS and fasciotomies without any corresponding diagnosis of ACS, compared to their counterparts; White patients had higher rates of ACS than patients of other races. Multivariate analysis showed that age was the only significant predictor of ACS across all groups.

This retrospective database study suggests that ACS is a rare complication of pediatric tibial tubercle fractures and that fasciotomies without any evidence of ACS—interpreted as prophylactic fasciotomies—occur at a higher rate than formally diagnosed ACS.

Level IV: Retrospective Cohort Study.

Efficiency and improved outcomes drive consolidation of total knee arthroplasty (TKA) services to higher-volume centers. Consequently, some patients may travel farther for arthroplasty care, potentially creating a new access barrier.

We investigated whether driving time to a reconstruction center was associated with progression to TKA among patients with newly diagnosed knee osteoarthritis (OA).

We conducted a retrospective review of data gathered from the electronic medical record of an academic health system serving a large geographic catchment for patients over 50 years old and newly diagnosed with knee OA between January 2021 and September 2022. One year TKA progression, setting of diagnosis, patient home ZIP code, and other information were recorded. The association between driving time and TKA progression was assessed using the Wilcoxon rank-sum test.

A total of 4106 patients were identified, resembling an expected OA population, with 61% women and 54% ages 50 to 64 years. Median driving time was 31 minutes, with 8% driving longer than 2 hours. In all, 299 patients (7.3%) progressed to TKA within 1 year. Median driving time was similar for OA patients who progressed to TKA (31 minutes; interquartile range [IQR], 19-78) versus OA patients who did not (31 minutes; IQR, 16-62). Notably, diagnosis in an orthopedic clinic was associated with increased odds of progression to TKA in patients with longer driving times, with no other subgroup associations.

Increased driving time was not associated with increased rates of 1 year progression to TKA in newly diagnosed OA patients. At least based on these results for patients able to receive a diagnosis of OA, driving time did not appear to pose a barrier to surgical management.

Level III: prognostic study.

Decreasing wound healing complications is important for total joint arthroplasty. 2-Octyl cyanoacrylate with polymer mesh tape (2OPMT) is a skin closure system that works by combining a liquid adhesive with a polymer mesh to form a waterproof microbial barrier over surgical wounds. However, allergic contact dermatitis (ACD) has been a reported complication of 2OPMT use, with an incidence ranging from 0.5% to 2.5%.

We sought to report our results of 2OPMT with primary total hip arthroplasty (THA) and total knee arthroplasty (TKA) and determine the incidence of ACD.

We conducted a single-institution, single-surgeon retrospective cohort study of 185 TKA and 154 THA patients who underwent procedures at a tertiary referral institution from October 2021 to November 2023.

Overall incidence of ACD associated with 2OPMT was 3.8% (13/339). Incidence of ACD in TKA was 3.8% (7/185) and in THA it was 3.9% (6/154). All skin reactions were recognized at the first postoperative visit and treated with a combination of topical and/or oral steroids and oral antihistamines. All ACD reactions resolved by the second postoperative visit, and none of these patients developed a surgical site infection or a periprosthetic joint infection.

We found an ACD incidence of 3.8% with 2OPMT use in TKA and THA. This is similar to other studies reporting on ACD in TKA and THA. While it can be treated with routine use of steroids, antihistamines, and antibiotics, ACD is uncomfortable for patients and presents them with a concerning clinical appearance that requires additional treatment.

Level III: retrospective cohort study.

Gaining operative proficiency requires adequate case volume during orthopedic residency training. Numerous surgical fields have demonstrated that male residents report higher case volume than female residents. In general surgery, racially/ethnically underrepresented in medicine residents report lower case volume than White residents.

We sought to evaluate differences in case volume between male and female orthopedic surgery residents and between White residents and those of other races and ethnicities at a single orthopedic residency.

Accreditation Council for Graduate Medical Education case logs were reviewed for orthopedic residents from 2010 to 2023 at a single institution. Overall residency case volume and volume by post-graduate year (PGY) were compared between men and women and between White and “other race” residents.

Of 111 residents included, 80.2% self-reported as men, 19.8% as women, 61.3% as White, non-Hispanic, and 32.4% as any other race (for 6.3%, race/ethnicity was unavailable). Overall, women logged a mean of 1865.6 cases while men logged a mean of 1861.0 cases, showing no difference based on gender. At the PGY-4 level, women logged more cases than men, with a mean of 430.3 for women versus 370.0 for men. There was no difference in overall case volume between White residents and those of “other” race/ethnicity, nor were there race/ethnicity-based differences by PGY level.

In contrast to prior studies, our retrospective single-institution review found no difference in overall case volume for orthopedic residents based on their self-reported gender or race/ethnicity. Institutions and the specialty at large should continue to create equitable surgical opportunities for orthopedic trainees, while future research should assess autonomy within cases.

The most common cancer in women worldwide, breast cancer most often metastasizes to the bone. Improved chemo- and radiotherapies and novel molecular therapies have prolonged survival in women with osseous metastatic breast cancer, but spinal metastases often cause cord compression that degrades their functional independence.

In women with breast cancer metastasized to the spine, we sought to (1) identify independent predictors of a functional deficit 3 months after surgical management and (2) assess the utility of existing metrics at highlighting patients at risk of a postoperative functional deficit.

We performed a single-institution, retrospective analysis of 92 patients meeting our inclusion criteria between 2004 and 2021. Patients were classified by 3-month postoperative Eastern Cooperative Oncology Group (ECOG) scores into good/independent (ECOG 0 to 2) and poor/dependent (ECOG 3 to 5) functional outcome groups. Univariate and multivariate analyses were performed to identify patient and tumor factors associated with good vs. poor 3-month ECOG scores.

Preoperative use of selective estrogen receptor modulators (SERMs) was significantly associated with good postoperative functional outcomes. Poor preoperative function, the presence of visceral metastases at the time of surgery, and triple-negative primary or metastatic tumor status were independently associated with poor 3-month postoperative function. Host characteristics, sociodemographic factors, and indicators of surgical complexity, including estimated blood loss, front/back surgery, and corpectomy reconstruction, were not associated with 3-month ECOG score. A multivariate model including these significant univariate associations and normalized for patient demographics identified preoperative SERM use, poor preoperative function (ECOG score), and triple-negative primary or metastatic tumor status as independently associated with functional status 3 months after surgery.

Our retrospective analysis found that preoperative SERM use was significantly associated with improved postoperative functional outcomes, while poor preoperative function and triple-negative tumor status were significantly associated with poor function 3 months after surgery. These factors may serve as indicators of function and independence after surgery for patients with metastatic breast cancer to the spine.

Level IV: Prognostic Study

Robotic assistance is becoming increasingly popular among surgeons performing total hip arthroplasty (THA). The impact of robotic assistance on the assessment of intraoperative stability and acetabular liner selection is not well described.

We sought to compare the incidence of intraoperative conversion from a neutral liner to a non-neutral liner in patients undergoing either robotic-assisted THA or manual THA.

We conducted a retrospective cohort study of patients who underwent primary THAs at our institution between January 1, 2018 and June 30, 2022. Partial hip arthroplasties, simultaneous bilateral hip arthroplasties, revision surgeries, and navigation-guided THAs were excluded. We identified 9614 primary THAs performed on 8807 patients; of these, 3875 were robotic-assisted THAs and 5739 were manual THAs. Liners were subcategorized into implanted versus wasted and neutral versus non-neutral (eg, elevated, lipped, lateralized, face changing, true constrained, and dual mobility). The primary outcome was the rate of intraoperative conversion from a neutral to non-neutral liner, defined as a wasted neutral liner followed by the implantation of a non-neutral liner.

Neutral liners were more frequently used in robotic-assisted THA than in manual THA (71% vs 42%, respectively), whereas elevated or lipped liners were more commonly used in manual THA than in robotic-assisted THA (34% vs 26%, respectively). After controlling for patient demographics and surgical variables, robotic-assisted THA had lower odds of conversion from a wasted neutral to an implanted non-neutral liner compared to manual THA.

Robotic-assisted THA is associated with a decreased rate of intraoperative liner conversion from a neutral to a non-neutral liner, suggesting that robotic assistance may provide greater stability during intraoperative assessments of implant placement.

Level III: retrospective cohort study.

Studies have shown that various types of spine surgery can be a contributing factor in bone loss, but the influence of lateral lumbar interbody fusion (LIF) on postoperative bone loss remains unclear.

We sought to investigate the influence of spine surgery, measured by quantitative computed tomography (QCT), on the adjacent vertebrae, and to evaluate the bone loss between stand-alone LIF (SA-LIF) and LIF supplemented with posterior pedicle screw-rod fixation (360° constructs).

We conducted a retrospective review of the records of patients who underwent SA-LIF and 360° constructs between 2016 and 2024. Inclusion criteria were (1) the interval between surgery and the secondary CT was 2 to 12 months; (2) the interval between the preoperative and postoperative CT was a minimum of 2 months; (3) the patient did not undergo additional spine surgery between those 2 CT scans; and (4) volumetric bone mineral density (vBMD) measurements of 1 level above the upper vertebra (UV+1) were possible in all cases. We excluded levels with a corpectomy, planned staged surgery, more than 4 levels of fusion, and poor QCT imaging quality. Postoperative changes in vBMD in the vertebrae at UV+1, UV+2, and 1 level below the lower vertebra (LV−1) were measured. Pre- and postoperative vBMDs were compared. Postoperative vBMD changes were also compared between the 2 groups.

Out of 191 patients who underwent the anterior or lateral interbody fusion in the specified time period, 72 patients met our inclusion criteria (36 SA-LIF; 63.3 ± 15.1 years, 36 360° constructs; 58.6 ± 11.3 years). UV+1 and UV+2 showed significant decreases in the SA-LIF group, and UV+2 and LV−1 decreased significantly in the 360° group. In the ANCOVA adjusted for age, the percent change in vBMD at each adjacent level showed no significant difference between the 2 groups.

Both SA-LIF and 360°construct surgeries negatively affected the postoperative vBMD values at adjacent levels. There was no statistically significant difference in bone loss between the 2 groups, suggesting that additional surgical invasiveness caused by screw insertion may not affect the severity of postoperative bone loss.

Level III: retrospective cohort study.

While much evidence exists on the epidemiology of and prevention strategies for anterior cruciate ligament (ACL) injuries, there is less information on patellar dislocations.

We sought to compare the activities of adolescents who underwent a medial patellofemoral ligament reconstruction (MPFLR) to those who underwent an ACL reconstruction (ACLR).

We conducted a retrospective review of routinely collected preoperative data of adolescent patients who underwent either an MPFLR or ACLR by 1 of 2 fellowship-trained pediatric sports medicine orthopedic surgeons at a single institution between February 1, 2016, and April 15, 2023. A total of 912 patients were identified, and 540 of these met the final inclusion and exclusion criteria. A total of 228 MPFLR participants were successfully matched to 228 ACLR participants based on sex and age within 1 year at the time of surgery. The mean age was 14.8 ± 2.1 years and 53% were female. The Hospital for Special Surgery Pediatric Functional Activity Brief Scale (HSS Pedi-FABS), Pediatric International Knee Documentation Committee, Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference, and PROMIS Mobility were collected.

We found that 61% of the MPFLR cohort and 94% of the ACLR cohort sustained their injuries while playing an organized sport. The MPFLR group had significantly lower HSS Pedi-FABS scores than the ACLR group, suggesting that the MPFLR group had lower preoperative athletic activity levels compared to the ACLR group.

In this retrospective study, participation in organized sports was associated with 61% of patellar dislocations. Among girls, dance was the second most common sport participated in at the time of patellar dislocation. This suggests that further investigation into injury prevention strategies for adolescent female dancers is warranted.

Level III: Retrospective therapeutic study.

Cervical disc arthroplasty (CDA) has gained widespread recognition as a motion-preserving alternative to anterior cervical discectomy and fusion for treating degenerative cervical disc disease. Over the past decade, the rate of CDA procedures has increased by a remarkable 654%. However, CDA complications can lead to a repeat procedure or can be converted to fusion.

We sought to evaluate the time of onset (early, intermediate, or late) of complications following CDA as well as the progression leading to revision surgeries.

A retrospective review of the Food and Drug Administration Manufacturer and User Facility Device Experience (MAUDE) database examined complications across 9 CDA devices from January 1, 2005, to September 30, 2023. Complications were categorized by postoperative time to occurrence: early (<6 months), intermediate (6-18 months), and late (>18 months). The revision procedures were categorized as either a repeat CDA or conversion to fusion.

A total of 688 CDA revision cases were reviewed, with 265 cases (38.5%) reporting revision onset time (median: 12 months, interquartile range: 3-36). Migration was the most frequent complication in both the early (n = 44, 53.0%) and intermediate (n = 25, 32.1%) periods. Subsidence peaked during the intermediate period (11.5%, n = 9), while neck pain and heterotopic ossification (HO) occurred most in the late postoperative phase, at 22.5% (n = 23) and 7.8% (n = 8), respectively. The specific revision type was recorded in 509 of the revision cases; of these, 8 devices were predominantly associated with fusion (>69%), while Mobi-C showed a lower proportion of fusion revisions (16.2%).

This retrospective review of the MAUDE database showed the timing of complications leading to CDA revision. Migration predominated in the early and intermediate phases, while subsidence peaked in the intermediate phase. In the late phase, neck pain, osteolysis, and HO become more prominent. Conversion to fusion was common across most devices. These data provide insight for clinicians to monitor patients after CDA while considering the relative frequencies of reported complications.

Level IV: retrospective analysis of a prospectively maintained government database.