Knee Surg Sports Traumatol Arthrosc DOI 10.1007/s00167-014-3332-7
HIP
Is early treatment of cam‑type femoroacetabular impingement the key to avoiding associated full thickness isolated chondral defects? Tim Claßen · Konrad Körsmeier · Michael Kamminga · Sascha Beck · Jan Rekowski · Marcus Jäger · Stefan Landgraeber
Received: 4 February 2014 / Accepted: 15 September 2014 © European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA) 2014
Abstract Purpose Hip arthroscopy is a safe and reproducible method for treating femoroacetabular impingement (FAI) and has evolved greatly in recent years. But little is known about the influences on the outcome after surgery. The aims of the current study were to elucidate (1) which parameters can be used as a marker for the presence of chondral and labral lesions, (2) the postoperative clinical outcome, and (3) at which time after surgery recovery occurs. Methods A prospective study was performed with 177 patients who underwent hip arthroscopy because of camtype FAI. The patients were examined preoperatively as well as 6 weeks and 6 months postoperatively, and their condition was rated according to the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and the Non-Arthritic Hip Score (NAHS). Statistical analyses were performed to evaluate the influence of independent factors such as “patient age,” “pain duration before surgery” on the clinical outcome, and the appearance of chondral or labral defects. Results The NAHS and WOMAC scores showed a significant enhancement 6 weeks after surgery. Only the NAHS showed a further improvement after 6 months. A positive correlation with the dependent variable “chondral
T. Claßen (*) · S. Beck · M. Jäger · S. Landgraeber Department of Orthopedics, University Duisburg-Essen, Pattbergstrasse 1‑3, 45239 Essen, Germany e-mail: [email protected] K. Körsmeier · M. Kamminga Facharztklinik Essen, Essen, Germany J. Rekowski Institute for Medical Informatics, Biometry and Epidemiology, University Duisburg-Essen, Essen, Germany
lesion” was evaluated for the independent variables “pain duration before surgery,” “preoperative NAHS,” and “labrum lesion”. Using ROC analysis, the optimal cutoff value of “pain duration before surgery” as a predictor was 9.5 months, for the NAHS 42.5 points. For the dependent variable, “6-month postoperative NAHS” significant correlations for the independent variables “age” and “pain duration before surgery” were revealed with a cutoff value of 55.5 years, respectively, 23.5 months. Conclusions It was concluded from the results that the date of surgery is relevant for the appearance of chondral defects. Patient age is a further relevant factor for clinical outcome. Recovery after hip arthroscopy takes place mainly in the first 6 weeks after surgery. Level of evidence Therapeutic study, Level III. Keywords Femoroacetabular impingement · Chondral defects · Hip arthroscopy
Introduction Over the past 10 years, femoroacetabular impingement (FAI) has become increasingly important as it is a certain cause of chondral lesion and consequently coxarthritis in long-term follow-up [13, 14]. It is responsible for many cases of coxarthritis which were previously classified as idiopathic. FAI occurs in two forms, the cam-type with a nonspherical femoral head due to excess bone at the femoral head–neck junction and the pincer type caused by excessive covering of the femoral head by the acetabulum [4]. A combination of both forms is observed in most patients with FAI [4, 6]. The first surgical techniques for treatment of the camtype FAI were described as open surgical procedures. But since then, arthroscopy has become an established method
13
of treatment which has been gradually and constantly improved. Most surgeons currently prefer hip arthroscopy for treatment of cam-type FAI as it allows efficient removal of most additional bone formations (bumps) in the femoral head–neck region. Furthermore, it is a safe and reproducible method for treating FAI, with a shorter rehabilitation time and lower complication rate than open luxation [23] and has evolved greatly in recent years [5, 29]. Apart from FAI, an increasing number of other pathologies are nowadays also treated by hip arthroscopy. This includes ligamentum teres injuries, synovitis, irritation of the psoas tendon, and labral and chondral defects [9, 12, 17, 18, 22]. Also extra-articular diseases and complaints after hip replacement are addressed by hip arthroscopy [3, 15, 24]. In contrast to the increasing number of treatment options, little is known about influences on the outcome after surgery. Aprato et al. [2] have recently shown for the first time that the outcome after hip arthroscopy depends on the time period between the onset of symptoms and surgery. Based on their data, they recommended arthroscopic treatment in the first 6 months after symptom onset and unsuccessful conservative treatment. The aims of the current study were to elucidate (1) which parameters can be used as a predictive marker for the appearance of chondral and labral lesions, (2) the postoperative clinical outcome, and (3) at which date after surgery recovery occurs, provided a reliable assessment of the postoperative outcome is possible. To answer these questions, a prospective study with 177 patients who underwent cam-type FAI-related hip arthroscopy was conducted. The hypothesis was that the study will provide predictive markers for postoperative outcome and the appearance of chondral and labral lesions. Findings would be of special relevance to orthopedic surgeons who are performing hip arthroscopy as it would enable an evaluation of the potential success and extent of the operation.
Materials and methods The study included 177 (95 female and 82 male) patients who underwent hip arthroscopy in 2011 because of symptomatic cam-type FAI which was diagnosed by radiographs of the hip in two planes. The alpha angle was measured at baseline on Lauenstein technique radiographs according to Notzli et al. [27]. An alpha angle threshold of 60° was used to define the presence of a cam deformity. This threshold has been recommended in various studies, including some recent ones [1]. Pincer type impingement was defined by a lateral center edge angle larger than 39° [32]. The mean age was 48.2 [standard deviation (SD) 13.9] years. Besides evaluation of age and sex, all patients were asked about the duration of their hip-related pain before
13
Knee Surg Sports Traumatol Arthrosc
surgery. Only patients with an insidious pain were included in this study. According to other authors with publications on the topic, the onset of insidious pain was defined as the first appearance of worsening symptoms at the hip [7, 8, 25]. Thus, the pain duration was defined as the time frame between onset of insidious pain and the surgery date. Additionally, a clinical examination with determination of the Non-Arthritic Hip Score (NAHS) and Klassbo et al.’s [10, 19] Western Ontario and McMaster Universities Arthritis Index (WOMAC) with a range from 0 (poor) to 100 (optimum) was performed. Additional re-evaluations took place 6 weeks and 6 months after surgery. The surgery was performed in the supine position on a trauma table, which allowed fluoroscopic guidance and traction of the hip joint. First, the peripheral part of the hip joint was accessed without extension by the superior anterolateral portal under fluoroscopic guidance. An additional anterior portal was created under arthroscopic guidance, and partial synovectomy and capsulotomy were performed, followed by evaluation of the peripheral part of the hip joint for existing pathophysiological conditions, e.g. cam-type impingement. Afterward, extension was performed, and the camera and instruments were directed to the central part of the hip joint. An additional anterolateral portal was created to achieve optimal evaluation for pathophysiological conditions in the central part for evaluation of further intraarticular pathologies such as ligamentum teres injuries, irritation of the psoas tendon, and labral tears. Cartilage damage was classified according to the Outerbridge classification [28]. Type I und II lesions were left untreated as they have a good prognosis, whereas type III and IV lesions were treated by microfracture or autologous chondrocyte implantation (ACI). For further evaluation, the treated type III and IV lesions, but not the type I and II lesions, were defined as “chondral lesion.” In all cases, resection at the head–neck junction was performed until the impingement was eradicated. Complete eradication of the cam-type impingement was confirmed fluoroscopically and by intraoperative arthroscopy-assisted functional examination with 80° flexion and maximum inner rotation of the leg. Any additional labral tears were debrided or refixed if necessary. Ligamentum teres injuries were treated by resection. In case of irritation of the psoas tendon, an endoscopic transcapsular psoas release from the peripheral compartment at the level of the hip joint was performed [16]. After surgery, the patients underwent a standardized rehabilitation program including lymph drainage as well as both active and passive physiotherapy. Partial weight-bearing was recommended for 3 days after surgery. Working patients returned to work after 4–6 weeks. Sport exercises were allowed after 8 weeks on a low level and after 3–4 months on a more intensive level. Only in cases with a labral refixation did we deviate from the aforementioned procedure: Partial
Knee Surg Sports Traumatol Arthrosc
weight-bearing with 15 kg was recommended for 4 weeks after surgery. Hip flexion was limited to 60° for the same time period. Hip rotation was not allowed for 6 weeks. Working patients remained absent from work for 8 weeks. Consequently, sport activities were also not permitted until later. Less intensive activities were recommended after 4 months and intensive activities after 6 months. This prospective, non-randomized study was approved by the Ethics Commission of the Medical Faculty of the University of Duisburg-Essen (12-5283-BO). Statistical analysis Summary statistics of the data were expressed as mean ± SD. Patient numbers were determined by the availability of subjects with FAI during the study period, rather than by a formal sample calculation. According to the literature, standard deviations of the differences of WOMAC and NAHS are quite certain between 5 and 20. With 177 patients included—assuming a power of 80 %—Student’s paired t test is able to detect effective sizes of 1.06, 2.12, 3.18, and 4.23 for true standard deviations of 5, 10, 15, and 20, respectively [20, 30]. As inspection of Q–Q plots for the differences of pre- and postoperative means of WOMAC and NAHS did not give any reason to doubt normality, paired t test was used. Contrary to these data, Q–Q plots suggested reasons to doubt normality for the differences of 6-week and 6-month scores. Accordingly, Wilcoxon signed-rank test was used to compare these later scores. In addition, categorical regression was performed for the dependent variables “cartilage damage,” “NAHS 6 months after surgery,” and “WOMAC 6 months after surgery” as well as for “labrum lesion,” The following parameters served as independent variables: “patient age,” “pain duration before surgery,” “preoperative NAHS,” “preoperative WOMAC,” and “labrum lesion.”
Finally, the prognostic values of “time between first symptoms and surgery date,” “patient age,” “preoperative NAHS,” and “preoperative WOMAC” on the presence of labrum, respectively, cartilage lesions as well as on the six-month postoperative NAHS and WOMAC scores were studied using a receiver operating characteristic (ROC) curve as far as the respective regression coefficient was significantly positive. For this purpose, a NAHS of less than 55 points, respectively, a WOMAC score of
HIP
Is early treatment of cam‑type femoroacetabular impingement the key to avoiding associated full thickness isolated chondral defects? Tim Claßen · Konrad Körsmeier · Michael Kamminga · Sascha Beck · Jan Rekowski · Marcus Jäger · Stefan Landgraeber
Received: 4 February 2014 / Accepted: 15 September 2014 © European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA) 2014
Abstract Purpose Hip arthroscopy is a safe and reproducible method for treating femoroacetabular impingement (FAI) and has evolved greatly in recent years. But little is known about the influences on the outcome after surgery. The aims of the current study were to elucidate (1) which parameters can be used as a marker for the presence of chondral and labral lesions, (2) the postoperative clinical outcome, and (3) at which time after surgery recovery occurs. Methods A prospective study was performed with 177 patients who underwent hip arthroscopy because of camtype FAI. The patients were examined preoperatively as well as 6 weeks and 6 months postoperatively, and their condition was rated according to the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and the Non-Arthritic Hip Score (NAHS). Statistical analyses were performed to evaluate the influence of independent factors such as “patient age,” “pain duration before surgery” on the clinical outcome, and the appearance of chondral or labral defects. Results The NAHS and WOMAC scores showed a significant enhancement 6 weeks after surgery. Only the NAHS showed a further improvement after 6 months. A positive correlation with the dependent variable “chondral
T. Claßen (*) · S. Beck · M. Jäger · S. Landgraeber Department of Orthopedics, University Duisburg-Essen, Pattbergstrasse 1‑3, 45239 Essen, Germany e-mail: [email protected] K. Körsmeier · M. Kamminga Facharztklinik Essen, Essen, Germany J. Rekowski Institute for Medical Informatics, Biometry and Epidemiology, University Duisburg-Essen, Essen, Germany
lesion” was evaluated for the independent variables “pain duration before surgery,” “preoperative NAHS,” and “labrum lesion”. Using ROC analysis, the optimal cutoff value of “pain duration before surgery” as a predictor was 9.5 months, for the NAHS 42.5 points. For the dependent variable, “6-month postoperative NAHS” significant correlations for the independent variables “age” and “pain duration before surgery” were revealed with a cutoff value of 55.5 years, respectively, 23.5 months. Conclusions It was concluded from the results that the date of surgery is relevant for the appearance of chondral defects. Patient age is a further relevant factor for clinical outcome. Recovery after hip arthroscopy takes place mainly in the first 6 weeks after surgery. Level of evidence Therapeutic study, Level III. Keywords Femoroacetabular impingement · Chondral defects · Hip arthroscopy
Introduction Over the past 10 years, femoroacetabular impingement (FAI) has become increasingly important as it is a certain cause of chondral lesion and consequently coxarthritis in long-term follow-up [13, 14]. It is responsible for many cases of coxarthritis which were previously classified as idiopathic. FAI occurs in two forms, the cam-type with a nonspherical femoral head due to excess bone at the femoral head–neck junction and the pincer type caused by excessive covering of the femoral head by the acetabulum [4]. A combination of both forms is observed in most patients with FAI [4, 6]. The first surgical techniques for treatment of the camtype FAI were described as open surgical procedures. But since then, arthroscopy has become an established method
13
of treatment which has been gradually and constantly improved. Most surgeons currently prefer hip arthroscopy for treatment of cam-type FAI as it allows efficient removal of most additional bone formations (bumps) in the femoral head–neck region. Furthermore, it is a safe and reproducible method for treating FAI, with a shorter rehabilitation time and lower complication rate than open luxation [23] and has evolved greatly in recent years [5, 29]. Apart from FAI, an increasing number of other pathologies are nowadays also treated by hip arthroscopy. This includes ligamentum teres injuries, synovitis, irritation of the psoas tendon, and labral and chondral defects [9, 12, 17, 18, 22]. Also extra-articular diseases and complaints after hip replacement are addressed by hip arthroscopy [3, 15, 24]. In contrast to the increasing number of treatment options, little is known about influences on the outcome after surgery. Aprato et al. [2] have recently shown for the first time that the outcome after hip arthroscopy depends on the time period between the onset of symptoms and surgery. Based on their data, they recommended arthroscopic treatment in the first 6 months after symptom onset and unsuccessful conservative treatment. The aims of the current study were to elucidate (1) which parameters can be used as a predictive marker for the appearance of chondral and labral lesions, (2) the postoperative clinical outcome, and (3) at which date after surgery recovery occurs, provided a reliable assessment of the postoperative outcome is possible. To answer these questions, a prospective study with 177 patients who underwent cam-type FAI-related hip arthroscopy was conducted. The hypothesis was that the study will provide predictive markers for postoperative outcome and the appearance of chondral and labral lesions. Findings would be of special relevance to orthopedic surgeons who are performing hip arthroscopy as it would enable an evaluation of the potential success and extent of the operation.
Materials and methods The study included 177 (95 female and 82 male) patients who underwent hip arthroscopy in 2011 because of symptomatic cam-type FAI which was diagnosed by radiographs of the hip in two planes. The alpha angle was measured at baseline on Lauenstein technique radiographs according to Notzli et al. [27]. An alpha angle threshold of 60° was used to define the presence of a cam deformity. This threshold has been recommended in various studies, including some recent ones [1]. Pincer type impingement was defined by a lateral center edge angle larger than 39° [32]. The mean age was 48.2 [standard deviation (SD) 13.9] years. Besides evaluation of age and sex, all patients were asked about the duration of their hip-related pain before
13
Knee Surg Sports Traumatol Arthrosc
surgery. Only patients with an insidious pain were included in this study. According to other authors with publications on the topic, the onset of insidious pain was defined as the first appearance of worsening symptoms at the hip [7, 8, 25]. Thus, the pain duration was defined as the time frame between onset of insidious pain and the surgery date. Additionally, a clinical examination with determination of the Non-Arthritic Hip Score (NAHS) and Klassbo et al.’s [10, 19] Western Ontario and McMaster Universities Arthritis Index (WOMAC) with a range from 0 (poor) to 100 (optimum) was performed. Additional re-evaluations took place 6 weeks and 6 months after surgery. The surgery was performed in the supine position on a trauma table, which allowed fluoroscopic guidance and traction of the hip joint. First, the peripheral part of the hip joint was accessed without extension by the superior anterolateral portal under fluoroscopic guidance. An additional anterior portal was created under arthroscopic guidance, and partial synovectomy and capsulotomy were performed, followed by evaluation of the peripheral part of the hip joint for existing pathophysiological conditions, e.g. cam-type impingement. Afterward, extension was performed, and the camera and instruments were directed to the central part of the hip joint. An additional anterolateral portal was created to achieve optimal evaluation for pathophysiological conditions in the central part for evaluation of further intraarticular pathologies such as ligamentum teres injuries, irritation of the psoas tendon, and labral tears. Cartilage damage was classified according to the Outerbridge classification [28]. Type I und II lesions were left untreated as they have a good prognosis, whereas type III and IV lesions were treated by microfracture or autologous chondrocyte implantation (ACI). For further evaluation, the treated type III and IV lesions, but not the type I and II lesions, were defined as “chondral lesion.” In all cases, resection at the head–neck junction was performed until the impingement was eradicated. Complete eradication of the cam-type impingement was confirmed fluoroscopically and by intraoperative arthroscopy-assisted functional examination with 80° flexion and maximum inner rotation of the leg. Any additional labral tears were debrided or refixed if necessary. Ligamentum teres injuries were treated by resection. In case of irritation of the psoas tendon, an endoscopic transcapsular psoas release from the peripheral compartment at the level of the hip joint was performed [16]. After surgery, the patients underwent a standardized rehabilitation program including lymph drainage as well as both active and passive physiotherapy. Partial weight-bearing was recommended for 3 days after surgery. Working patients returned to work after 4–6 weeks. Sport exercises were allowed after 8 weeks on a low level and after 3–4 months on a more intensive level. Only in cases with a labral refixation did we deviate from the aforementioned procedure: Partial
Knee Surg Sports Traumatol Arthrosc
weight-bearing with 15 kg was recommended for 4 weeks after surgery. Hip flexion was limited to 60° for the same time period. Hip rotation was not allowed for 6 weeks. Working patients remained absent from work for 8 weeks. Consequently, sport activities were also not permitted until later. Less intensive activities were recommended after 4 months and intensive activities after 6 months. This prospective, non-randomized study was approved by the Ethics Commission of the Medical Faculty of the University of Duisburg-Essen (12-5283-BO). Statistical analysis Summary statistics of the data were expressed as mean ± SD. Patient numbers were determined by the availability of subjects with FAI during the study period, rather than by a formal sample calculation. According to the literature, standard deviations of the differences of WOMAC and NAHS are quite certain between 5 and 20. With 177 patients included—assuming a power of 80 %—Student’s paired t test is able to detect effective sizes of 1.06, 2.12, 3.18, and 4.23 for true standard deviations of 5, 10, 15, and 20, respectively [20, 30]. As inspection of Q–Q plots for the differences of pre- and postoperative means of WOMAC and NAHS did not give any reason to doubt normality, paired t test was used. Contrary to these data, Q–Q plots suggested reasons to doubt normality for the differences of 6-week and 6-month scores. Accordingly, Wilcoxon signed-rank test was used to compare these later scores. In addition, categorical regression was performed for the dependent variables “cartilage damage,” “NAHS 6 months after surgery,” and “WOMAC 6 months after surgery” as well as for “labrum lesion,” The following parameters served as independent variables: “patient age,” “pain duration before surgery,” “preoperative NAHS,” “preoperative WOMAC,” and “labrum lesion.”
Finally, the prognostic values of “time between first symptoms and surgery date,” “patient age,” “preoperative NAHS,” and “preoperative WOMAC” on the presence of labrum, respectively, cartilage lesions as well as on the six-month postoperative NAHS and WOMAC scores were studied using a receiver operating characteristic (ROC) curve as far as the respective regression coefficient was significantly positive. For this purpose, a NAHS of less than 55 points, respectively, a WOMAC score of
