Knee Surg Sports Traumatol Arthrosc DOI 10.1007/s00167-014-2893-9
HIP
Complications in hip arthroscopy: necessity of supervision during the learning curve Florian Dietrich • Christian Ries • Claus Eiermann Wolfgang Miehlke • Christian Sobau
•
Received: 30 October 2013 / Accepted: 31 January 2014 Ó Springer-Verlag Berlin Heidelberg 2014
Abstract Purpose The aim of this study was to determine whether the learning curve of arthroscopic treatment of femoroacetabular impingement (FAI) could be verified by analyzing the complication rate of this procedure. Additionally, it was investigated whether supervision by an experienced surgeon leads to a steeper learning curve (lower number of complications) when starting to perform arthroscopic FAI treatment. Methods The complications occurring in 317 consecutive patients treated with the sole diagnosis of FAI were analyzed. 256 patients (collective A) were treated by surgeon A between June 2005 and January 2010. Sixty-one patients (collective B) were treated by surgeon B between August 2008 and December 2009. From January to June 2008, surgeon B performed many hip arthroscopies under supervision of surgeon A. Complications were recorded in a central complication register. Statistic analysis of the complication rates was performed using Fischer’s exact T test. Results Subdividing collective A chronologically into thirds a significant decline of complications (p = 0.0044) was found with growing experience of the surgeon.
F. Dietrich (&) C. Eiermann W. Miehlke ARCUS Kliniken, Rastatter Str. 17-19, 75179 Pforzheim, Germany e-mail: [email protected] C. Ries Department of Trauma and Orthopaedic Surgery, University of Cologne, Kerpener Str. 62, 50937 Cologne, Germany C. Sobau Orthopaedie Kurpfalz, Hasenackerstr. 13-17, 68163 Mannheim, Germany
Comparing the first 61 patients of both surgeons a significantly lower complication rate was discovered in the patients of surgeon B (p = 0.0375). In total there were 21 complications (6.6 %; CI 4.4–9.9 %). The observed complication rate was 7.0 % in collective A and 4.9 % in collective B. Conclusion The learning curve can be comprehended by the distribution of complications in collective A. Having spent 6 months performing under supervision of surgeon A, surgeon B has a lower complication rate than surgeon A when comparing the first 61 patients each surgeon operated on. This implies that surgeon B benefits from the experience of surgeon A. According to this analysis, beginners in arthroscopic FAI treatment should be taught at a specialized centre to reduce the number of complications. Level of evidence III. Keywords Hip arthroscopy Femoroacetabular impingement Learning curve Complication Supervision
Introduction Femoroacetabular impingement (FAI) is a common cause of hip pain in adolescents and adults. It is a frequent disorder that is caused by morphologic variations involving the proximal femur and the acetabulum leading to an impingement between femur and acetabulum [18, 23]. This repetitive traumatizing of the cartilage on the acetabular rim and the neighbouring labrum often leads to groin pain. If not treated by re-establishing an anatomical situation avoiding impingement (Fig. 1), early-onset osteoarthritis of the hip can be the consequence [1, 4, 15]. This can be achieved by surgical hip dislocation via greater trochanter flip osteotomy resecting the pathological bone and
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Knee Surg Sports Traumatol Arthrosc
Fig. 1 Pre- and postoperative AP-view of a hip joint with combined femoroacetabular impingement (FAI). a Preoperative X-ray showing a major cam deformity (arrow) and a prominent acetabular rim.
b Postoperative image showing anatomical correction of the cam deformity (arrow) and a reduction of the acetabular rim
Fig. 2 Intraoperative view of a cam deformity; a preoperative image; b postoperative image
reconstructing the labrum [13]. This gold standard intervention, however, is quite traumatizing for the patient requiring long recovery times. In order to minimalize invasiveness, arthroscopic techniques for the resection of impinging structures (Fig. 2) have been developed [8, 9]. The results in recent literature prove that hip arthroscopy is an established procedure for the treatment of FAI [25] making it an alternative to surgical hip dislocation which benefits the patient by providing faster recovery and better short-term results [3, 5, 9, 26–28]. Hip arthroscopy is an emerging surgical technique [12] gaining importance in the treatment of numerous articular and peri-articular pathologies over the last years [7]. Due to its configuration as a ball joint, its thick soft tissue envelope and its strong articular capsule, arthroscopy of the hip
123
is connected with more technical difficulties than arthroscopy of other major joints. Overcoming these difficulties is technically demanding and bears the risk of a variety of potential complications [17, 19, 20]. The complication rates in literature range from 1.34 [6, 10] to 8 % [16, 21]. Differences in indication, patient selection and definition of complication could be responsible for these deviations. Learning hip arthroscopy is time-consuming [22] and some publications show a comparably flat learning curve [19]. Most of these publications examine hip arthroscopy in general without dealing with the particular case of FAI treatment. The arthroscopic treatment of FAI is a particularly challenging procedure as the pathology usually involves major parts of the joint that can only be visualized partially.
Knee Surg Sports Traumatol Arthrosc
In this Study, the learning curve of arthroscopic FAI treatment was investigated by analyzing complication rates. The hypothesis was that the complication rate would show a significant decline over time with growing experience of the surgeon. There are no previous studies investigating the dynamics of complications of arthroscopic FAI treatment in a comparable number of patients. This study provides important information about types and probability of complications that are relevant for every surgeon practicing hip arthroscopy. Furthermore, in this study, the effect of a surgeon working under supervision of an experienced colleague over an extended period of time before performing the procedure on his own was analyzed. It has been assumed that the apprentice benefited from the experience of his colleague entering the learning curve at a higher level thus creating fewer complications. Such an effect has not been described previously. This could lead to a new approach in teaching arthroscopic FAI treatment in specialized centres, where apprentices perform surgery under supervision of experienced colleagues.
Materials and methods In this study, a very broad definition of complications was used. Every unexpected event, during and after surgery was recorded in the complication register. All patients enrolled in this study gave their informed consent before being included in this register. For further processing, the data were rendered anonymous. The complications occurring in 317 consecutive patients who underwent hip arthroscopy for the sole diagnosis of FAI between June 2005 and January 2010 were retrospectively analyzed. All hip arthroscopies were performed in supine position using a standard fracture table. All patients had general anaesthesia. Anterolateral and anterior standard portals were used to achieve access to the central compartment. In some cases, the high anterolateral portal was used for accessing the peripheral compartment and sometimes the mid anterior portal for reconstruction of the labrum. Drainages were not used. In order to achieve comparable data, patients showing pathologies other than FAI e.g. loose bodies, osteoarthritis were excluded. Every patient underwent at least two clinical examinations. The first one took place on the second day after surgery, and the second one 6 weeks postoperatively. The complications were documented in an electronic KIS-System using a standardized process available to everybody involved in the treatment of the patient. Of the total 317 patients, 256 were treated by surgeon A between June 2005 and January 2010. The remaining 61 patients were treated by surgeon B between August 2008
and December 2009. From January to July 2008, surgeon B performed 53 hip arthroscopies under supervision of surgeon A. Those patients having varying diagnoses were not part of this study. To examine the learning curve of surgeon A, the 256 patients (collective A) were subdivided into three chronological groups of equal size. In order to determine the effect of surgeon A’s supervision of surgeon B, the complications occurring in the first 61 patients treated alone by each surgeon were analyzed. As a retrospective analysis of anonymous data, this study was approved by the ethics committee of Baden-Wu¨rttemberg (state) without being assigned an ID number. Statistical analysis For statistical analysis of the data, Fisher’s exact test was used. P values smaller than 0.05 were regarded statistically significant.
Results Analyzing all 317 patients, 21 complications were registered (6.6 %; CI 4.4–9.9 %) (Fig. 3). In 6 patients, it was not possible to accomplish sufficient distraction during surgery. Accordingly the central compartment was not directly reachable and the arthroscopy had to be started in the peripheral compartment. In six patients, postoperative hematoma were observed, which delayed their recovery. Two of these patients had to undergo surgical revision. In 4
Fig. 3 Distribution of the 21 complications observed in all 317 patients treated with the diagnosis of femoroacetabular impingement (FAI)
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Knee Surg Sports Traumatol Arthrosc
cases, the patients had persisting pain 3 months after surgery. As the cause of the pain, insufficient resection of the cam deformity was detected necessitating re-arthroscopy. In all 4 patients, satisfying results could be achieved after revision. Two patients showed postoperative neurapraxia of the pudendal nerve, which declined over the following month without residue. In two cases, instrument breakage occurred intra-articular. In one patient, a fracture of the femoral neck was observed 3 days after surgery, after early postoperative weight bearing. For further analysis, collective A was subdivided into chronological thirds (two groups of 85 patients and one group of 86 patients). The number of complications within each group was compared (Fig. 4). Of a total of 18 (7.0 %; CI 4.5–10.8 %) observed complications, 10 (11.8 %; CI 6.5–20.3 %) happened within the first group (4 hematoma, 3 insufficient distraction, 2 insufficient cam resection, 1 instrument breakage). In the second group, 7 (8.2 %; CI 4.1–16.0 %) complications (2 insufficient distraction, 2 neurapraxia (n. pudendus), 1 femoral neck fracture, 1 instrument breakage, 1 hematoma) were recorded. In the third group, one (1.2 %; CI 0.2–6.4 %) complication (1 insufficient distraction) was observed. This shows a continuous decline of the complication rate over the time within the groups and a statistically significant difference (p = 0.0044) comparing the first and the third group.
Table 1 Complications in the first 61 patients of surgeon A compared with the complications in the first 61 patients of surgeon Surgeon A
Surgeon B
Patients
Complication type
Patients
Complication type
3
Insufficient distraction
2
Insufficient cam resection
4 (surgical revision 2)
Hematoma
1
Hematoma
2
Insufficient cam resection
1
Instrument breakage
Before starting to perform arthroscopic FAI treatment, surgeon B performed many hip arthroscopies under supervision of surgeon A. Comparing the complication rate, we found surgeon B having a statistically significant (p = 0.0375) lower amount of complications than surgeon A
Analyzing the first 61 cases surgeon B performed alone in comparison with the first 61 patients of surgeon A, a total of 10 (16.4 %; CI 9.2–27.6 %) complications (4 hematoma, 3 insufficient distraction, 2 insufficient cam resection, 1 instrument breakage) were found in the patients of surgeon A and a total of 3 (4.9 %; CI 1.7–13.5 %) complications (2 insufficient cam resection, 1 hematoma) in the patients of surgeon B (Table 1). Comparing the number of complications in their respective first 61 patients, surgeon B was found to have a significantly (p = 0.0375) lower amount of complications than surgeon A.
Discussion
Fig. 4 Development of complications over the time in 256 Patients treated by surgeon A. The complications of the three groups are subdivided by complication type
123
The major finding of the present study was the effectiveness of supervision by an experienced surgeon in order to minimize the complication rate when starting to perform arthroscopic FAI treatment. Training surgeons in new techniques is a crucial part of assuring medical progress and making state-of-the-art treatment available to a majority of patients. It is difficult, however, to combine patients’ interests with the training of surgeons in new techniques, especially if the procedure is technically demanding and the learning curve comparably flat. Hip arthroscopy has been proven to be a safe procedure with complication rates not being higher than in open surgery of the hip [11]. It has become one of the standard procedures in the treatment of FAI [2, 3, 14]. Even though considered a safe procedure [17] when performed by an experienced surgeon, one remaining problem is its comparably flat learning curve. Our investigation shows a statistically significant reduction of complications if the surgeon is trained to perform the procedure under the supervision of
Knee Surg Sports Traumatol Arthrosc
an experienced colleague before starting to operate on his own. This finding can be used in order to shorten the learning curve by establishing programs to facilitate the training of surgeons under supervision of an experienced mentor. The second important finding of this study is the association of complication rate and experience of the surgeon. This proves the importance of specialization in order to perform complicated, technically demanding procedures safely. The general decline of the complication rate in with growing experience of the surgeon is no unexpected finding. Interestingly complications such as hematoma or insufficient distraction show a continuous decline over the time. Insufficient cam resection on the other hand was only observed within the first group. In the second group, we observed a femoral neck fracture but no cases of insufficient cam resection. In the third group we found neither insufficient cam resection nor femoral neck fracture. It can be argued that this pattern also shows a learning process where the effort to avoid one type of complication leads to another. Only after completing the learning curve both complications can be avoided. It remains to be discussed whether the observed reduction of complications leads to an improvement in outcome quality. It seems logical that fewer complications also mean better postoperative results. Proving this thesis is a space for further investigation using standardized outcome protocols e.g. iHOT 33 [24]. Other studies have investigated this subject showing a lower complication rate being closely linked to outcome quality [19]. We therefore suggest that learning hip arthroscopy under prolonged supervision is not only useful because of complication reduction, which on its own is a reasonable benefit. It can furthermore be assumed that this effect leads to a higher percentage of satisfying postoperative results. A potential source of error in this study is the possible difference in technical skills of surgeon A and B. Before starting hip arthroscopy both surgeons, however, had many years of experience in orthopedic surgery and arthroscopic surgery of other joints, making this explanation unlikely. Another source of potential inaccuracy is the missing stratification of FAI into cam-type and pincer-type impingement. As both types of FAI require different arthroscopic procedures, potential complications may vary. To clarify these differences could be the task of future investigations. In this study, any unexpected event during and after surgery was recorded in the register. This very broad definition of complications leads to comparably high complication rates in our collective. It could be discussed whether insufficient distraction forcing the surgeon to start surgery in the peripheral compartment should be regarded as a complication at all. Other authors have suggested that
only incidents prolonging the recovery of the patient (for more than 6 month) or necessitating a revision procedure should be regarded as complications [20]. Taking this definition into account, the overall complication rate in our collective is 1.9 %; CI 0.1–4.1 % (6 of 317). Major complications are defined as events that threaten the patient’s life or endanger the function of the treated limb. In one case, we had a major complication (femoral neck fracture) 0.3 %; CI 0.06–1.7 %. Those complication rates are similar to the findings in other publications dealing with this topic [6, 10, 20]. This study provides important data about potential complications of arthroscopic FAI treatment. Being aware of complications is necessary for every surgeon in order to prevent them. Strategies for the reduction of complications, as suggested in this study, are important to ensure patients’ safety in this emerging procedure.
Conclusion It could be proven in this study that the complication rate of arthroscopic FAI treatment declines significantly with growing experience of the surgeon. It therefore can be concluded that in order to assure a safe treatment specialization is mandatory. Apart from that it could be shown that supervision by an expert colleague during the learning process leads to a lower complication rate when starting to perform arthroscopic FAI treatment. In addition to technical courses, specialized centres should therefore engage in programs providing fellowships by senior surgeons to trainees in hip arthroscopy.
References 1. Beck M, Kalhor M, Leunig M, Ganz R (2005) Hip morphology influences the pattern of damage to the acetabular cartilage: femoroacetabular impingement as a cause of early osteoarthritis of the hip. J Bone Joint Surg Br 87(7):1012–1018 2. Bedi A, Kelly BT, Khanduja V (2013) Arthroscopic hip preservation surgery: current concepts and perspective. Bone Joint J 95-B(1):10–19 3. Botser IB, Smith TW Jr, Nasser R, Domb BG (2011) Open surgical dislocation versus arthroscopy for femoroacetabular impingement: a comparison of clinical outcomes. Arthroscopy 27(2):270–278 4. Bredella MA, Ulbrich EJ, Stoller DW, Anderson SE (2013) Femoroacetabular impingement. Magn Reson Imaging Clin N Am 21(1):45–64 5. Buchler L, Neumann M, Schwab JM, Iselin L, Tannast M, Beck M (2013) Arthroscopic versus open cam resection in the treatment of femoroacetabular impingement. Arthroscopy 29(4):653–660
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Knee Surg Sports Traumatol Arthrosc 6. Byrd T (2001) Hip arthroscopy. The supine position. Clin Sports Med 20(4):703–731 7. Byrd T (2006) Hip arthroscopy: surgical indications. Arthroscopy 22(12):1260–1262 8. Byrd T, Jones KS (2009) Arthroscopic femoroplasty in the management of cam-type femoroacetabular impingement. Clin Orthop Relat Res 467(3):739–746 9. Byrd T, Jones KS (2009) Arthroscopic management of femoroacetabular impingement. Instr Course Lect 58:231–239 10. Clarke MT, Arora A, Villar RN (2003) Hip arthroscopy: complications in 1,054 cases. Clin Orthop Relat Res 406:84–88 11. Clohisy JC, St John LC, Schutz AL (2010) Surgical treatment of femoroacetabular impingement: a systematic review of the literature. Clin Orthop Relat Res 468(2):555–564 12. Colvin AC, Harrast J, Harner C (2012) Trends in hip arthroscopy. J Bone Joint Surg Am 94(4):e23 13. Espinosa N, Beck M, Rothenfluh DA, Ganz R, Leunig M (2007) Treatment of femoro-acetabular impingement: preliminary results of labral refixation. Surgical technique. J Bone Joint Surg Am 89(Suppl 2 Pt.1):36–53 14. Fayad TE, Khan MA, Haddad FS (2013) Femoroacetabular impingement: an arthroscopic solution. Bone Joint J 95-B(11 Suppl A):26–30 15. Ganz R, Parvizi J, Beck M, Leunig M, Notzli H, Siebenrock KA (2003) Femoroacetabular impingement: a cause for osteoarthritis of the hip. Clin Orthop Relat Res 417:112–120 16. Harris JD, McCormick FM, Abrams GD, Gupta AK, Ellis TJ, Bach BR Jr, Bush-Joseph CA, Nho SJ (2013) Complications and reoperations during and after hip arthroscopy: a systematic review of 92 studies and more than 6,000 patients. Arthroscopy 29(3):589–595 17. Ilizaliturri VM Jr (2009) Complications of arthroscopic femoroacetabular impingement treatment: a review. Clin Orthop Relat Res 467(3):760–768 18. Ito K, Minka MA 2nd, Leunig M, Werlen S, Ganz R (2001) Femoroacetabular impingement and the cam-effect. A MRIbased quantitative anatomical study of the femoral head-neck offset. J Bone Joint Surg Br 83(2):171–176
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19. Konan S, Rhee SJ, Haddad FS (2011) Hip arthroscopy: analysis of a single surgeon’s learning experience. J Bone Joint Surg Am 93(Suppl 2):52–56 20. Kowalczuk M, Bhandari M, Farrokhyar F, Wong I, Chahal M, Neely S, Gandhi R, Ayeni OR (2012) Complications following hip arthroscopy: a systematic review and meta-analysis. Knee Surg Sports Traumatol Arthrosc 21(7):1669–1675 21. Larson CM, Giveans MR, Taylor M (2011) Does arthroscopic FAI correction improve function with radiographic arthritis? Clin Orthop Relat Res 469(6):1667–1676 22. Lee YK, Ha YC, Hwang DS, Koo KH (2012) Learning curve of basic hip arthroscopy technique: CUSUM analysis. Knee Surg Sports Traumatol Arthrosc 21(8):1940–1944 23. Leunig M, Beaule PE, Ganz R (2009) The concept of femoroacetabular impingement: current status and future perspectives. Clin Orthop Relat Res 467(3):616–622 24. Mohtadi NG, Griffin DR, Pedersen ME, Chan D, Safran MR, Parsons N, Sekiya JK, Kelly BT, Werle JR, Leunig M, McCarthy JC, Martin HD, Byrd JW, Philippon MJ, Martin RL, Guanche CA, Clohisy JC, Sampson TG, Kocher MS, Larson CM, Multicenter Arthroscopy of the Hip Outcomes Research N (2012) The Development and validation of a self-administered quality-of-life outcome measure for young, active patients with symptomatic hip disease: the International Hip Outcome Tool (iHOT-33). Arthroscopy 28(5):595–605 25. Ng VY, Arora N, Best TM, Pan X, Ellis TJ (2010) Efficacy of surgery for femoroacetabular impingement: a systematic review. Am J Sports Med 38(11):2337–2345 26. Sampson TG (2006) Arthroscopic treatment of femoroacetabular impingement: a proposed technique with clinical experience. Instr Course Lect 55:337–346 27. Tran P, Pritchard M, O’Donnell J (2012) Outcome of arthroscopic treatment for cam type femoroacetabular impingement in adolescents. ANZ J Surg 83(5):382–386 28. Zingg PO, Ulbrich EJ, Buehler TC, Kalberer F, Poutawera VR, Dora C (2013) Surgical hip dislocation versus hip arthroscopy for femoroacetabular impingement: clinical and morphological shortterm results. Arch Orthop Trauma Surg 133(1):69–79
HIP
Complications in hip arthroscopy: necessity of supervision during the learning curve Florian Dietrich • Christian Ries • Claus Eiermann Wolfgang Miehlke • Christian Sobau
•
Received: 30 October 2013 / Accepted: 31 January 2014 Ó Springer-Verlag Berlin Heidelberg 2014
Abstract Purpose The aim of this study was to determine whether the learning curve of arthroscopic treatment of femoroacetabular impingement (FAI) could be verified by analyzing the complication rate of this procedure. Additionally, it was investigated whether supervision by an experienced surgeon leads to a steeper learning curve (lower number of complications) when starting to perform arthroscopic FAI treatment. Methods The complications occurring in 317 consecutive patients treated with the sole diagnosis of FAI were analyzed. 256 patients (collective A) were treated by surgeon A between June 2005 and January 2010. Sixty-one patients (collective B) were treated by surgeon B between August 2008 and December 2009. From January to June 2008, surgeon B performed many hip arthroscopies under supervision of surgeon A. Complications were recorded in a central complication register. Statistic analysis of the complication rates was performed using Fischer’s exact T test. Results Subdividing collective A chronologically into thirds a significant decline of complications (p = 0.0044) was found with growing experience of the surgeon.
F. Dietrich (&) C. Eiermann W. Miehlke ARCUS Kliniken, Rastatter Str. 17-19, 75179 Pforzheim, Germany e-mail: [email protected] C. Ries Department of Trauma and Orthopaedic Surgery, University of Cologne, Kerpener Str. 62, 50937 Cologne, Germany C. Sobau Orthopaedie Kurpfalz, Hasenackerstr. 13-17, 68163 Mannheim, Germany
Comparing the first 61 patients of both surgeons a significantly lower complication rate was discovered in the patients of surgeon B (p = 0.0375). In total there were 21 complications (6.6 %; CI 4.4–9.9 %). The observed complication rate was 7.0 % in collective A and 4.9 % in collective B. Conclusion The learning curve can be comprehended by the distribution of complications in collective A. Having spent 6 months performing under supervision of surgeon A, surgeon B has a lower complication rate than surgeon A when comparing the first 61 patients each surgeon operated on. This implies that surgeon B benefits from the experience of surgeon A. According to this analysis, beginners in arthroscopic FAI treatment should be taught at a specialized centre to reduce the number of complications. Level of evidence III. Keywords Hip arthroscopy Femoroacetabular impingement Learning curve Complication Supervision
Introduction Femoroacetabular impingement (FAI) is a common cause of hip pain in adolescents and adults. It is a frequent disorder that is caused by morphologic variations involving the proximal femur and the acetabulum leading to an impingement between femur and acetabulum [18, 23]. This repetitive traumatizing of the cartilage on the acetabular rim and the neighbouring labrum often leads to groin pain. If not treated by re-establishing an anatomical situation avoiding impingement (Fig. 1), early-onset osteoarthritis of the hip can be the consequence [1, 4, 15]. This can be achieved by surgical hip dislocation via greater trochanter flip osteotomy resecting the pathological bone and
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Knee Surg Sports Traumatol Arthrosc
Fig. 1 Pre- and postoperative AP-view of a hip joint with combined femoroacetabular impingement (FAI). a Preoperative X-ray showing a major cam deformity (arrow) and a prominent acetabular rim.
b Postoperative image showing anatomical correction of the cam deformity (arrow) and a reduction of the acetabular rim
Fig. 2 Intraoperative view of a cam deformity; a preoperative image; b postoperative image
reconstructing the labrum [13]. This gold standard intervention, however, is quite traumatizing for the patient requiring long recovery times. In order to minimalize invasiveness, arthroscopic techniques for the resection of impinging structures (Fig. 2) have been developed [8, 9]. The results in recent literature prove that hip arthroscopy is an established procedure for the treatment of FAI [25] making it an alternative to surgical hip dislocation which benefits the patient by providing faster recovery and better short-term results [3, 5, 9, 26–28]. Hip arthroscopy is an emerging surgical technique [12] gaining importance in the treatment of numerous articular and peri-articular pathologies over the last years [7]. Due to its configuration as a ball joint, its thick soft tissue envelope and its strong articular capsule, arthroscopy of the hip
123
is connected with more technical difficulties than arthroscopy of other major joints. Overcoming these difficulties is technically demanding and bears the risk of a variety of potential complications [17, 19, 20]. The complication rates in literature range from 1.34 [6, 10] to 8 % [16, 21]. Differences in indication, patient selection and definition of complication could be responsible for these deviations. Learning hip arthroscopy is time-consuming [22] and some publications show a comparably flat learning curve [19]. Most of these publications examine hip arthroscopy in general without dealing with the particular case of FAI treatment. The arthroscopic treatment of FAI is a particularly challenging procedure as the pathology usually involves major parts of the joint that can only be visualized partially.
Knee Surg Sports Traumatol Arthrosc
In this Study, the learning curve of arthroscopic FAI treatment was investigated by analyzing complication rates. The hypothesis was that the complication rate would show a significant decline over time with growing experience of the surgeon. There are no previous studies investigating the dynamics of complications of arthroscopic FAI treatment in a comparable number of patients. This study provides important information about types and probability of complications that are relevant for every surgeon practicing hip arthroscopy. Furthermore, in this study, the effect of a surgeon working under supervision of an experienced colleague over an extended period of time before performing the procedure on his own was analyzed. It has been assumed that the apprentice benefited from the experience of his colleague entering the learning curve at a higher level thus creating fewer complications. Such an effect has not been described previously. This could lead to a new approach in teaching arthroscopic FAI treatment in specialized centres, where apprentices perform surgery under supervision of experienced colleagues.
Materials and methods In this study, a very broad definition of complications was used. Every unexpected event, during and after surgery was recorded in the complication register. All patients enrolled in this study gave their informed consent before being included in this register. For further processing, the data were rendered anonymous. The complications occurring in 317 consecutive patients who underwent hip arthroscopy for the sole diagnosis of FAI between June 2005 and January 2010 were retrospectively analyzed. All hip arthroscopies were performed in supine position using a standard fracture table. All patients had general anaesthesia. Anterolateral and anterior standard portals were used to achieve access to the central compartment. In some cases, the high anterolateral portal was used for accessing the peripheral compartment and sometimes the mid anterior portal for reconstruction of the labrum. Drainages were not used. In order to achieve comparable data, patients showing pathologies other than FAI e.g. loose bodies, osteoarthritis were excluded. Every patient underwent at least two clinical examinations. The first one took place on the second day after surgery, and the second one 6 weeks postoperatively. The complications were documented in an electronic KIS-System using a standardized process available to everybody involved in the treatment of the patient. Of the total 317 patients, 256 were treated by surgeon A between June 2005 and January 2010. The remaining 61 patients were treated by surgeon B between August 2008
and December 2009. From January to July 2008, surgeon B performed 53 hip arthroscopies under supervision of surgeon A. Those patients having varying diagnoses were not part of this study. To examine the learning curve of surgeon A, the 256 patients (collective A) were subdivided into three chronological groups of equal size. In order to determine the effect of surgeon A’s supervision of surgeon B, the complications occurring in the first 61 patients treated alone by each surgeon were analyzed. As a retrospective analysis of anonymous data, this study was approved by the ethics committee of Baden-Wu¨rttemberg (state) without being assigned an ID number. Statistical analysis For statistical analysis of the data, Fisher’s exact test was used. P values smaller than 0.05 were regarded statistically significant.
Results Analyzing all 317 patients, 21 complications were registered (6.6 %; CI 4.4–9.9 %) (Fig. 3). In 6 patients, it was not possible to accomplish sufficient distraction during surgery. Accordingly the central compartment was not directly reachable and the arthroscopy had to be started in the peripheral compartment. In six patients, postoperative hematoma were observed, which delayed their recovery. Two of these patients had to undergo surgical revision. In 4
Fig. 3 Distribution of the 21 complications observed in all 317 patients treated with the diagnosis of femoroacetabular impingement (FAI)
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cases, the patients had persisting pain 3 months after surgery. As the cause of the pain, insufficient resection of the cam deformity was detected necessitating re-arthroscopy. In all 4 patients, satisfying results could be achieved after revision. Two patients showed postoperative neurapraxia of the pudendal nerve, which declined over the following month without residue. In two cases, instrument breakage occurred intra-articular. In one patient, a fracture of the femoral neck was observed 3 days after surgery, after early postoperative weight bearing. For further analysis, collective A was subdivided into chronological thirds (two groups of 85 patients and one group of 86 patients). The number of complications within each group was compared (Fig. 4). Of a total of 18 (7.0 %; CI 4.5–10.8 %) observed complications, 10 (11.8 %; CI 6.5–20.3 %) happened within the first group (4 hematoma, 3 insufficient distraction, 2 insufficient cam resection, 1 instrument breakage). In the second group, 7 (8.2 %; CI 4.1–16.0 %) complications (2 insufficient distraction, 2 neurapraxia (n. pudendus), 1 femoral neck fracture, 1 instrument breakage, 1 hematoma) were recorded. In the third group, one (1.2 %; CI 0.2–6.4 %) complication (1 insufficient distraction) was observed. This shows a continuous decline of the complication rate over the time within the groups and a statistically significant difference (p = 0.0044) comparing the first and the third group.
Table 1 Complications in the first 61 patients of surgeon A compared with the complications in the first 61 patients of surgeon Surgeon A
Surgeon B
Patients
Complication type
Patients
Complication type
3
Insufficient distraction
2
Insufficient cam resection
4 (surgical revision 2)
Hematoma
1
Hematoma
2
Insufficient cam resection
1
Instrument breakage
Before starting to perform arthroscopic FAI treatment, surgeon B performed many hip arthroscopies under supervision of surgeon A. Comparing the complication rate, we found surgeon B having a statistically significant (p = 0.0375) lower amount of complications than surgeon A
Analyzing the first 61 cases surgeon B performed alone in comparison with the first 61 patients of surgeon A, a total of 10 (16.4 %; CI 9.2–27.6 %) complications (4 hematoma, 3 insufficient distraction, 2 insufficient cam resection, 1 instrument breakage) were found in the patients of surgeon A and a total of 3 (4.9 %; CI 1.7–13.5 %) complications (2 insufficient cam resection, 1 hematoma) in the patients of surgeon B (Table 1). Comparing the number of complications in their respective first 61 patients, surgeon B was found to have a significantly (p = 0.0375) lower amount of complications than surgeon A.
Discussion
Fig. 4 Development of complications over the time in 256 Patients treated by surgeon A. The complications of the three groups are subdivided by complication type
123
The major finding of the present study was the effectiveness of supervision by an experienced surgeon in order to minimize the complication rate when starting to perform arthroscopic FAI treatment. Training surgeons in new techniques is a crucial part of assuring medical progress and making state-of-the-art treatment available to a majority of patients. It is difficult, however, to combine patients’ interests with the training of surgeons in new techniques, especially if the procedure is technically demanding and the learning curve comparably flat. Hip arthroscopy has been proven to be a safe procedure with complication rates not being higher than in open surgery of the hip [11]. It has become one of the standard procedures in the treatment of FAI [2, 3, 14]. Even though considered a safe procedure [17] when performed by an experienced surgeon, one remaining problem is its comparably flat learning curve. Our investigation shows a statistically significant reduction of complications if the surgeon is trained to perform the procedure under the supervision of
Knee Surg Sports Traumatol Arthrosc
an experienced colleague before starting to operate on his own. This finding can be used in order to shorten the learning curve by establishing programs to facilitate the training of surgeons under supervision of an experienced mentor. The second important finding of this study is the association of complication rate and experience of the surgeon. This proves the importance of specialization in order to perform complicated, technically demanding procedures safely. The general decline of the complication rate in with growing experience of the surgeon is no unexpected finding. Interestingly complications such as hematoma or insufficient distraction show a continuous decline over the time. Insufficient cam resection on the other hand was only observed within the first group. In the second group, we observed a femoral neck fracture but no cases of insufficient cam resection. In the third group we found neither insufficient cam resection nor femoral neck fracture. It can be argued that this pattern also shows a learning process where the effort to avoid one type of complication leads to another. Only after completing the learning curve both complications can be avoided. It remains to be discussed whether the observed reduction of complications leads to an improvement in outcome quality. It seems logical that fewer complications also mean better postoperative results. Proving this thesis is a space for further investigation using standardized outcome protocols e.g. iHOT 33 [24]. Other studies have investigated this subject showing a lower complication rate being closely linked to outcome quality [19]. We therefore suggest that learning hip arthroscopy under prolonged supervision is not only useful because of complication reduction, which on its own is a reasonable benefit. It can furthermore be assumed that this effect leads to a higher percentage of satisfying postoperative results. A potential source of error in this study is the possible difference in technical skills of surgeon A and B. Before starting hip arthroscopy both surgeons, however, had many years of experience in orthopedic surgery and arthroscopic surgery of other joints, making this explanation unlikely. Another source of potential inaccuracy is the missing stratification of FAI into cam-type and pincer-type impingement. As both types of FAI require different arthroscopic procedures, potential complications may vary. To clarify these differences could be the task of future investigations. In this study, any unexpected event during and after surgery was recorded in the register. This very broad definition of complications leads to comparably high complication rates in our collective. It could be discussed whether insufficient distraction forcing the surgeon to start surgery in the peripheral compartment should be regarded as a complication at all. Other authors have suggested that
only incidents prolonging the recovery of the patient (for more than 6 month) or necessitating a revision procedure should be regarded as complications [20]. Taking this definition into account, the overall complication rate in our collective is 1.9 %; CI 0.1–4.1 % (6 of 317). Major complications are defined as events that threaten the patient’s life or endanger the function of the treated limb. In one case, we had a major complication (femoral neck fracture) 0.3 %; CI 0.06–1.7 %. Those complication rates are similar to the findings in other publications dealing with this topic [6, 10, 20]. This study provides important data about potential complications of arthroscopic FAI treatment. Being aware of complications is necessary for every surgeon in order to prevent them. Strategies for the reduction of complications, as suggested in this study, are important to ensure patients’ safety in this emerging procedure.
Conclusion It could be proven in this study that the complication rate of arthroscopic FAI treatment declines significantly with growing experience of the surgeon. It therefore can be concluded that in order to assure a safe treatment specialization is mandatory. Apart from that it could be shown that supervision by an expert colleague during the learning process leads to a lower complication rate when starting to perform arthroscopic FAI treatment. In addition to technical courses, specialized centres should therefore engage in programs providing fellowships by senior surgeons to trainees in hip arthroscopy.
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