National and regional arthroplasty registries have been growing and expanding since the Swedish Knee Arthroplasty Register was established in 1975. Shortly after, this practice was adopted by other Scandinavian countries, and today, many countries with developed healthcare systems use registry platforms for gathering and processing information related to the surgical replacement of major joints.‌^[1] The data processing from such systems enables surgeons worldwide to identify poorly performing implants and unsuccessful surgical techniques, thereby enhancing their level of competence by selecting the most suitable products and proper surgical procedures for their patients. Furthermore, similar software provides options for follow-up patients with joint replacements and facilitates data processing for annual reports associated with this intervention.^[2]

At present, there is no state-approved software in Bulgaria that allows surgeons practicing within our country to input their patients’ data. The only electronic database recording the number of implanted endoprosthesis is related to medical products within the Bulgarian Drug Agency. The information provided by such sources is quantitative only, that is, they just record the number of implanted devices. It is impossible to draw statistical conclusions or analyze accomplished results based on so small amounts of data. The existence of an arthroplasty registry is crucial, not only for ensuring optimal healthcare but also for the optimization of the expenses related to the treatment and rehabilitation of patients undergoing joint replacement surgeries.

The purpose of this study was to present the initial experience of the Orthopedics and Traumatology Clinic at Tsaritsa Joanna University Hospital, ISUL, using the OrthoWave™ system.

In November 2022, the first form of an arthroplasty register in Bulgaria was initiated. The OrthoWave application was used for this purpose, providing access to 6 centers in Bulgaria.^[3] Participation in the register was entirely voluntary, and the software was provided free of charge to all 6 centers. The presented materials are from the Orthopedics and Traumatology Clinic at Tsaritsa Joanna University Hospital, ISUL. From November 1, 2022, to August 31, 2023, 215 patients with 218 knee and hip prostheses were added to the register (145 hip replacements, 73 knee replacements). The demographic indicators of sex, age, and BMI, and characteristics of the surgical procedure such as intervention execution time, approach used, type and size of prostheses, were gathered and analyzed.

The sex distribution differed between the two cohorts, with men accounting for 61.38% and women for 38.62% of hip endoprosthesis surgeries. Among patients with knee endoprostheses, women were predominant accounting for 58.9%, whereas operated men were 41.1%. The mean BMI of all operated individuals was 29.3 kg/m². The average weight during surgery was 93 kg, with an average height of 176 cm. The mean age of patients at the time of surgery was 66.11 years (Fig. 1).

In terms of total operation time, the average was 38 minutes for treatments involving the hip joints and 49 minutes for surgeries involving the knee joints. An analysis of the implants used in patients with hip endoprostheses showed the following results: the most commonly used acetabular component was 52 mm, and the most frequently utilized stem was size 12. A head size of 36 mm was used in more than 50% of the cases. Cementless fixation of the components was used in 72% of the cases and a Dual-Mobility cup appeared in 7%. In 114 hip surgeries, the lateral-transgluteal approach was used, 29 were performed using the Rottinger approach, and two hip prostheses were implanted using the Kocher-Langenbeck approach. All knee joint replacements were performed using the medial parapatellar approach. A cruciate retaining prosthesis was used in 37% of the patients while a posterior-stabilized artificial joint appeared in the rest of the cases (Figs 2, 3).

traditionally, the value of clinical information is determined by its place in the hierarchy of clinical evidence. The basis of this hierarchy is to establish causal connections concerning the demonstrated results. Different designs of clinical trials provide varying degrees of reliability of information, with randomized control clinical trials being accepted as having the highest level of reliability.^[4] In this aspect, the format of a practice registry represents an observational study encompassing a vast cohort of participants. To make such a database indicative, participation of the greatest number of hospitals, surgeons, patients, operative techniques, and implants is of great importance.‌^[5] Our initial experience is related to the work of 6 centers and an insufficient number of surgeons, which we acknowledge as a primary weakness of the present study. Popularizing the Bulgarian Arthroplasty Register should be a priority for the organizations of Bulgarian orthopedists within the country.

The impact of the registries on orthopedic practice has been obvious since the creation of the Swedish registry. The first large, long-term study based on registry data demonstrated the significance of cementing techniques and proper implant selection. Furthermore, the inclusion of hemiarthroplasties in the database in 2005 contributed to favoring the lateral approach for this procedure, significantly reducing the risk of dislocation.^[6]

The results reported by patients form the basis of follow-ups and reflect the relationship between a given intervention and the change in quality of life after its performance. Two main types of scores for assessment are prevalent in ISAR studies (International Society of Arthroplasty Registries). They are generic (reflecting overall health) and specific (focused on specific symptoms, diseases, and functions).^[7] Comparing these methods for assessing the condition before and after the intervention demonstrates patient satisfaction and serves as a solid argument for the operation choice of a surgeon. Our software allows validation of such scores both preoperatively and during the follow-up period.

Despite the undeniable advantages of having a national arthroplasty register, there are many difficulties associated with both its management and funding. In most cases, national registries are maintained by the national orthopedic associations of a given country. In other cases, the government manages the registries or works closely with federal health authorities. Both models seem to have shown successful results, but a message from Kolling and colleagues evidently emphasizes the importance of cooperation among individual structures.^[8]

The presented study reflects the immense significance and immediate benefits of an arthroplasty registry for both the orthopedic community and patients undergoing endoprosthetic treatment. Our initial experience with the OrthoWave software demonstrated that it is optimized for everyday practice and enables comprehensive statistical analysis of the entered data. Its development on a national level is still ahead of us.

A.P. drafted the manuscript, G.L. and G.L. performed the statistical analysis, and S.D., S.I., and P.K. edited the final draft.

The authors have no support to report.

The authors have no funding to report.

The authors have declared that no competing interests exist.