Stress Fracture and Pubalgia: Spatiotemporal Trends, Revisit Rates and Causes

Research Article

Phys Med Rehabil Int. 2018; 5(1): 1137.

Stress Fracture and Pubalgia: Spatiotemporal Trends, Revisit Rates and Causes

Pedrinelli A*, Hernandes AJ, Ejnisman L, Fagotti L, de Almeida AM and Lazaretti T

Grupo de Medicina d Esporte, Instituto de Ortopedia e Traumatologia do Hospital das Clinicas (HCFMUSP), Faculdade de Medicina, Universidade de S&aTilde;o Paulo, SP, Brazil

*Corresponding author: Pedrinelli A, Grupo de Medicina d Esporte, Instituto de Ortopedia e Traumatologia do Hospital das Clinicas (HCFMUSP), Faculdade de Medicina, Universidade de S&aTilde;o Paulo, SP, Brazil

Received: December 18, 2017; Accepted: January 31, 2018; Published: February 08, 2018


Background: Pubalgia and pelvic stress fractures are common among athletes, with different therapeutic options having achieved varying rates of pain reduction and early return to sport activities.

Aims: We aimed to evaluate the rate of 90-day hospital revisits and its determinants after a surgical procedure for pubalgia and a diagnosis pelvic stress fracture, and to assess the trend of pelvic stress fracture prevalence over time.

Methods: This was a longitudinal secondary data analysis of patients undergoing surgical procedures for pubalgia and stress fracture of the pelvis in Florida, Kentucky and Maryland, derived from three HCUP state-specific databases.

Results: Of 2,112 subjects with pubalgia, the average age was 44.2 (± 23), 53.8% were female, 61% white and 15.9% were readmitted, the mean revisit time being 6.35 (± 18) days. Risk factors for revisits included age > 42 [OR: 2.41 (1.89, 3.09)], female gender, and a Charlson comorbidity score > 0 [OR: 2.3 (1.74, 3.01)]. The 678 participants with stress fractures presented a mean age of 65 years (± 19.1), 77% were female, 87% White, with a revisit rate of 24.9% with an average time of 8.65 (± 20.3). Increased 90-day revisit rates were associated with a Charlson co-morbidity score > 0 [OR: 3.11 (2.16, 4.52)] and Van Walraven score > 0 [OR: 2.53 (1.78, 3.64)], whereas private insurance payment decreased the risk of revisits.

Conclusion: Comorbidities and age significantly increased the risk of revisits for both conditions, while being female was an independent risk factor for pubalgia patients.

Keywords: Pubalgia; Stress fracture; Revisit; Spatiotemporal trend


NSAIDs: Nonsteroidal Anti-Inflammatory Drugs; FAI: Femoroacetabular Impingement; MRI: Magnetic Resonance Imaging; SID: State Inpatient Database; SASD: State Ambulatory Surgery Database; SEDD: State Emergency Department Database; STROBE: STrengthening the Reporting of OBservational Studies in Epidemiology; HCUP: Healthcare Cost and Utilization Project; AHRQ: Agency for Healthcare Research and Quality; AHA: American Hospital Association.


Pubalgia (groin pain) is a common cause of early retirement in many sports disciplines [1] and is frequently observed among athletes who perform sudden cutting, pivoting and kicking movements [1,2]. Pubalgia remains a diagnostic and therapeutic challenge [3–6]. The repetitive use of the pubis symphysis with the resulting progressive lesions on rectus abdominus, adductor muscles (rectaladductor syndrome) and the symphysis itself (osteitis pubis and joint injury) account for 40% of Pubalgia cases. “Sports hernia” or anteroinferior abdominal wall insufficiency is responsible for another 40% of pubalgia cases while diseases of the neighboring structures including the hip, iliopsoas, hamstring, sacroiliac, nerves as well as urogenital diseases account for 20% [7]. Athletic pubalgia, intraarticular hip pathologies (labral/femoroacetabular impingement), traumatic myotendinous ruptures (hip adductors, rectus abdominis), and diseases of the abdominal wall (inguinal hernias) are considered as differential diagnoses [1]. Recent consensus suggests a diagnostic classification based on five clinical entities; adductor, hip joint, pubic bone stress injury, iliopsoas-, and abdominal wall-related pathology [3]. Initial therapy for pubalgia is usually conservative consisting of massage, heat or ice, and NSAIDs, followed by rehabilitation. However, available evidence suggests that nonsurgical approach is unsuccessful. Surgical treatment options include open and laparoscopic repair of the abdominal wall and pelvic floor muscles as well as arthroscopy for femoroacetabular impingement (FAI) when the latter is comorbidity. Laparoscopic repair allows earlier return to sporting activities [8]. In one series, 32% of patients required arthroscopy for FAI after muscle repair surgery for pubalgia [2]. Another series reported 89% of patients returning to sports after both pubalgia surgery and arthroscopy for FAI were performed [9,10] as opposed to 25% following pubalgia surgery alone, and 50% with arthroscopy for FAI alone [2]. Optimum outcomes and unrestricted return to sports have been reported especially with concurrent, staged management of pubalgia surgery and arthroscopy [11].

Different treatment modalities for pubalgia and pelvic stress fractures have shown varying degrees of success at reducing pain and permitting the return to normal activities. However, no study to the best of our knowledge has described the trends on readmissions and revisits geographically over time.

Stress fractures which include fatigue and insufficiency fractures are frequently seen among sportsmen and women [12], as a result of repetitive stress on bone [13,14]. Rarely, they may result from radiotherapy [15]. Fatigue fractures result from the constant application of abnormal stresses on a normal bone while insufficiency fractures are due to normal cyclical loading on abnormal bone [14]. Stress fractures are more common in females [16] than males. Stress fractures of the pelvis are relatively rare making up just about 1-2% of all stress injuries [13,14,17] but can be particularly devastating since they require a longer rehabilitation period of approximately 6-12 months compared with 4-8 weeks for stress fractures at other sites [17]. They are more common among track and field athletes and those involved in other running sports disciplines [12]. The sites of the fractures typically vary with sports disciplines [12] and with the age of the subject. Fibular and tibial stress fractures occur mostly in the younger athletes while femoral and tarsal stress fractures are more frequent in the older [17]. In the adult, most of the repetitive injuries occur concurrently in the sacrum, pubic rami, and symphysis [14,15]. Pubic rami fractures which are more common in women, result in pain in the adductor, inguinal or perineal region [13]. Plain radiographs and MRI are the major diagnostic procedures for stress fractures [13,15,18]. Initial management is conservative, comprising analgesia, bed rest [18–20] with cessation of the precipitating activity [16] followed by an ‘active’ therapy where the athlete continues physical exercises depending on the fracture site [16]. In insufficiency fractures, this initial phase precedes anabolic or antiresorptive medications (calcium and vitamin D supplements, bisphosphonates, and teriparatide) meant to reduce the risk of further fractures [18– 20]. Electrical stimulation and extracorporeal shock wave therapy as adjunctive therapies have been reported to hasten recovery and return to sporting activities [19,20]. Surgery is required when the fracture site is unstable or in the setting of neurological deficits or disruption in the alignment of the sacrum. Osteosynthesis with screws or hinge fixation is the procedure of choice [19]. Reinforcement with methylmethacrylate cement [18,19], bone graft or bone graft substitutes have also been used to enhance fracture healing [18].

A prospective, randomized study of athletes with sports hernia reported that the surgical repair (laparoscopic mesh repair) was more efficient than conservative therapy, with 90% of patients who received surgical mesh returning to sporting activities within three months and being pain-free at the one-year follow-up [21]. Hip arthroscopy performed concomitantly for comorbid FAI has also been shown to enable a return to sporting activities [11]. However, few studies have reported the use of validated outcome measures. The Doha agreement identifies a significant association with methodologically weaker studies reporting higher rates of positive treatment outcomes [22]. The rates of readmissions, revisits, and their distribution over time and geographical regions are yet to be described.

According to the Hospital Readmissions Reduction Program created by the Patient Protection and Affordable Care Act, establishing surgical readmission rates is crucial, since they engender quality care and cost-containment [23]. Rates of readmission following surgery vary extensively, from 9% to 50%, across US hospitals [24–27]. In one series, 51.5% of those who had been discharged after surgery were either rehospitalized or died within the first year following discharge [27]. Postoperative complications are the most important risk factors for post-surgery readmissions [26,28]. Other risk factors reported among orthopedic patients include the length of hospitalization or admission to the intensive care unit, race, marital status and Medicaid insurance status. The latter three factors may indicate the state of a patient’s social and economic resources [29]. Other risk factors include index surgical admission complications, non-home discharge, patient comorbidities, teaching hospital status, and higher surgical volume. Surgical site infection is reported to be the most common reason for surgical readmissions [28]. Although some of these risk factors and reasons for surgical readmissions can apply to pubalgia and pelvic stress fracture patients who undergo surgical management, they are not specific to these patients. Indeed, risk factors and reasons for revisits and readmissions of pubalgia and pelvic stress fracture patients managed surgically, and the geographical pattern in which they occur over time is unknown.

In light of this gap in the literature, the objectives of our study are to (1) Evaluate the rate of 90-day hospital revisits and its risk factors following a surgical procedure for pubalgia and a diagnosis of stress pelvic fractures using three State HCUP databases. (2) Evaluate the trend of prevalence of stress fractures of the pelvis over time using spatial time series.

Materials and Methods

Study design

This study is a secondary data analysis of a longitudinal followup of patients undergoing surgical procedures for pubalgia and a diagnosis of stress fracture of the pelvis in Florida, Kentucky and Maryland as derived from three HCUP state-specific databases: The State Inpatient Database (SID), the State Ambulatory Surgery Database (SASD) and the State Emergency Department Database (SEDD). This study evaluates (1) The rate of 90-day hospital revisits following surgical procedures for pubalgia and a diagnosis of stress pelvic fractures as well as the corresponding risk factors and (2) the spatiotemporal trend in the prevalence of pelvic stress fractures This study is described per the STROBE (STrengthening the Reporting of OBservational studies in Epidemiology) guidelines [30].


The Institutional Review Board of the University of Sao Paulo, Brazil approved our study.


The Healthcare Cost and Utilization Project (HCUP) is a system of databases composed of patient data reported by state and private data organizations, hospital associations and the federal government. It is sponsored by the Agency for Healthcare Research and Quality (AHRQ). We obtained data from three HCUP databases: The State Inpatient Database (SID) [31], the State Ambulatory Surgery Database (SASD) [32] and the State Emergency Department Database (SEDD) [33] in Florida, Kentucky, and Maryland for three years. The databases include de-identified discharge records for individual patients from all sources of coverage - Medicare, Medicaid, private insurance, and self-pay/uninsured. The SID consists of discharge records of all inpatient hospital visits including those admitted via the emergency department, the SASD covers ambulatory survey visits and release, and the SEDD reports records from emergency department visits that do not result in an admission. Individual patient records across all three databases were linked and tracked using an encrypted patientlevel identifier. Our study focused on patients who underwent surgical procedures for pubalgia, and stress fracture of the pelvis in Florida, Kentucky, and Maryland between the years 2010 and 2013.

The HCUP databases contain links to the AHA Annual Survey data elements containing additional hospital-specific indicators calculated from the American Hospital Association (AHA) data. The HCUP American Hospital Association (AHA) Linkage Files were used to link all the HCUP states databases with hospital-level longitude and latitude.


We identified patients who underwent a surgical procedure for pubalgia (ICD9 diagnostic code 848.8; CPT codes: 27299, 49659, 49999; ICD9 procedure code: 8045) or had a diagnosis of stress fracture of the pelvis (ICD9 diagnostic code: 73398; 73396) from 2010 to 2013 in Florida, Kentucky and Maryland. We excluded patients with previous abductor-tendon lesions, and inguinal hernia operations.

We defined the index surgical procedure as the first surgery for each pubalgia patient or the first index visit for patients with stress fractures from 2010 to 2013. The encrypted patient identifier connecting patients to subsequent procedures was used to calculate 90-day hospital revisit rates.

Outcomes measures

The 90-day hospital revisit rates and risk factors associated with revisits were analyzed using visit linkage variables across patient encounters. The time between the index procedure and hospital revisit in each of the three databases was used to calculate readmission rates. We defined a 90-day hospital readmission as a readmission to an ambulatory surgery center or inpatient hospital admission within 90 days from the index procedure. The other outcome variable was the spatial location of the visit between 2010 and 2013 as determined by the longitude and latitude of the hospital where care was provided.

Demographic data were defined at the time of the index procedure including age, race, patient residence (large metropolitan =1 million residents, small metropolitan ›1 million residents, micropolitan between 10,000 and 50,000 residents, or neither metropolitan nor micropolitan), primary expected payer (Medicaid, Medicare, private insurance, self-pay, or other). Co-morbidities categorized using the International Classification of Diseases (ICD-9). Mainly, Deyo- Charlson Comorbidity Index [34] and the Elixhauser-van Walraven Comorbidity Index [35] were also considered to determine their possible effect on surgical complication and revisit. Both indices are validated for their ability to predict mortality [36,37]. The Charlson Comorbidity Index is a weighted score derived from the sum of the scores for each of the comorbidities [34,35]. The Elixhauser-van Walraven Comorbidity Index includes a set of 30 acute and chronic comorbidity indicators, and the index score is based on the total number of comorbidity categories required to predict in-hospital mortality [35,38]. The cutoffs of ›5 for Charlson score and ›23 for Van Walraven score were chosen to represent the median so that we would have a similar number of subjects in each group, following a convention in a similar range from other publications [39,40].

Statistical methods

Our exploratory analysis started by evaluating the distributions, frequencies, and percentages for each of the numeric and categorical variables and then assessing categorical variables for near-zero variation or categorical variables with a low frequency of observations [41].

Our modeling strategy to evaluate risk factors employed a series of logistic regression models for the odds ratio and 95% confidence intervals of revisit within 90 days from the surgical procedure for pubalgia and a diagnosis of a stress fracture of the pelvis. Survival curves were calculated using Kaplan-Meier plots. To evaluate the geographical spread of surgical procedures and diagnoses for each of the pubalgia and stress fracture conditions over time, we used the longitude and latitude of each hospital facility (available from the American Hospital Association Database) where patients received care, stratified by year. We displayed years in consecutive maps. All analyses were performed using the R language [42].


Descriptive data

Regarding pelvic stress fracture, our sample comprised 678 individuals with a mean age of 65 years old (± 19.1), 77% were female, and 87% were White. Medicare was the most common payment mechanism covering 62.7% of the population. The vast majority of our sample (95.3%) lived in metropolitan areas. The mean Charlson comorbidity index was 1.01 (± 1.57) while the mean Van Walraven score was 2.94 (± 5.92). Revisit rate was 24.9% and average time to those who had a revisit was 8.65 (± 20.3) days after the medical encounter. Across the study period, only the proportion of subjects with a lower socioeconomic status increased from 2009 to 2013 (Table 1).