In-hospital costs for total hip replacement performed using the supercapsular percutaneously-assisted total hip replacement surgical technique

Results from the current study show use of the SuperPath technique was associated with a reduction in in-hospital costs of 15.1 %. The cost difference increased to 36.1 % when implant costs were excluded. This agreed well with a recent study from Canada showing a 28.4 % reduction in in-hospital costs, excluding implants, when using SuperPath compared to the traditional lateral approach [7]. The current study is the first to examine the economic impact of using this technique in the United States.

Anesthesia, operating room, and physical/occupational therapy costs were all significantly higher in group B. The reduction in anesthesia costs seen in group A was possibly due to the procedure not requiring the use of blocks or regional anesthesia, which are commonly used in THR. Operating room cost reductions could be due to the decreased need for surgical assistants compared to traditional THR techniques or the need for expensive specialty tables or apparatuses as required by some techniques (e.g., some variants of the direct anterior approach) [8, 9]. The SuperPath technique was performed with a single surgical assistant without the need for any specialty tables or apparatuses in all cases. As mentioned previously, both operating and anesthesia times were reduced approximately six minutes in group A. It is unlikely though, that such a small improvement alone would result in such high cost reductions.

Pharmacy costs were 25.3 % higher in group B and when only opioid costs were examined the difference increased to 49.2 %. These costs included any drug delivered during the hospital stay. The reduction in pharmacy costs was likely multifactorial. Only oral medications were used in group A patients. No patient-controlled analgesia or boutique medications (e.g., intravenous Tylenol or Exparel) were used in any group A patients. Finally, the use of minimally-invasive or tissue-sparing techniques has been shown to reduce pain levels and the amount of pain medication consumed [10‐12]. Therefore, it is likely that the group A patients consumed less pain medication, and in particular powerful opioids, on average due to the sparing of the musculature and surrounding soft tissues.

The transfusion rate in group A was nearly 14 % lower than that of group B, resulting in mean transfusion cost savings of 88.2 %. Transfusion rates can be affected by several factors including the amount of soft tissue damage caused by the surgical technique. As previously mentioned, the SuperPath technique does not require the cutting of muscles or tendons by utilizing the interval between the piriformis and the gluteus medius. Another factor affecting transfusion rates is the use of antifibrinolytics. In group A, 95.9 % of patients received aminocaproic acid and the remaining 4.1 % received tranexamic acid. Nearly a third (33.2 %) of patients in group B received tranexamic acid and 27.7 % received aminocaproic acid. When examining only those patients receiving aminocaproic acid, the transfusion rate was 1.7 % (7 of 402) in group A and 7.4 % (35 of 470) in group B. This suggests the surgical technique and not choice of antifibrinolytics could be responsible for the reduction in the need for transfusions. Only a single study could be found comparing the effectiveness of aminocaproic and tranexamic acid for preventing transfusions following joint replacement [13]. That study found nearly five times (12.5 vs. 2.8 %) as many aminocaproic acid patients required transfusion as did tranexamic acid patients. Interestingly in the current study, 7.4 % (35 of 470) of group B patients receiving aminocaproic acid and 20.5 % (114 of 557) of group B patients receiving tranexamic acid required transfusions.

Over 91 % of patients in group A were routinely discharged home compared with just 29.6 % of group B. While discharge status does not affect in-hospital costs, it does have a potentially significant impact on costs for hospitals participating in bundling. Bozic et al. reported over 35 % of charges associated with a 30-day episode of care were related to post-discharge care, with 70 % of postdischarge payments due to discharging patients to post-acute care facilities [14]. Ramos et al. reported the average costs for discharge to an inpatient rehabilitation facility, skilled nursing facility, and home with care as $16,464, $6,678, and $4,239, respectively [15]. These studies emphasize the potential significant benefit of reducing inpatient rehabilitation facility discharges from 6.7 % in group B to 0.9 % in group A. Similar to discharge status, readmission rates do not impact in-hospital costs but are significant in a bundling scenario. Bozic et al. also reported the cost burden of unplanned THR readmissions to be 4.3 % and the average costs of each readmission to be $17,103 [16]. The readmission rate for group A was over seven times lower than that of group B (0.4 vs. 2.9 %) in the current study.

While the current study is a review of data independently collected by a hospital system on a large group of patients, there are several limitations. The two groups had some differences in population characteristics. Group A was nearly four years younger and had 3.5 % more male patients. Efforts were made to control the indications and diagnoses for the procedure during patient selection criteria, but not all aspects could be controlled. There was a single surgeon performing the SuperPath procedure and it is therefore possible that the skill of the surgeon and not the technique itself could bias results. There are multiple surgeons included in group B and there are a number of factors (e.g., surgical technique, implant selection, surgeon skill) that could affect results. There are also multiple hospitals included in group B and therefore differences in conditions or procedures (e.g., indications for transfusion) at each of these centers could affect costs.

A final limitation is that this study does not include the learning curve associated with the SuperPath technique, as the single surgeon had significant previous experience with the technique. Costs during the learning curve with a technique can be higher due to the potential for increased LOS, transfusions, surgical time, complications, and readmissions. The previously mentioned study comparing the SuperPath technique to the traditional lateral included the initial 49 SuperPath surgeries performed by the author [7]. This study found complication rates and associated in-hospital costs were all lower in the SuperPath group even during this learning curve phase.

In conclusion, the use of the SuperPath technique resulted in reductions of in-hospital costs, LOS, and readmissions when compared to all other THRs performed in a large hospital system in the United States. Additionally, over 60 % more patients were discharged directly home. Future studies are needed to determine the economic impact of this technique across an entire 30-day episode of care and to compare to specific surgical techniques.