Original Article With Video Illustration
Ligamentum Teres Injury Is Associated With the Articular Damage Pattern in Patients With Femoroacetabular Impingement Mitsunori Kaya, M.D., Tomoyuki Suziki, M.D., Takeshi Minowa, M.D., and Toshihiko Yamashita, M.D.
Purpose: The objective of this study was to investigate the association between ligamentum teres injury and the hip joint cartilage damage pattern in patients with femoroacetabular impingement. Methods: We compared articular cartilage damage between ligamentum tereseintact anderuptured hips. Data were collected for 77 consecutive patients with femoroacetabular impingement who underwent hip arthroscopy. The locations of the chondral lesions were recorded on anatomic articular maps using the geographic zone method. The patients were divided into 2 groups (ligamentum tereseintact andeinjured groups), and the incidence and degree of cartilage injury were compared between the 2 groups by use of the Mann-Whitney U test. Results: In patients with ligamentum teres injury, chondral damage extended to the middle-inferior area of the acetabulum (7.6% [grade 1] in ligamentum tereseintact group and 66.6% [grade 1, 12.1%; grade 2, 42.4%; grade 3, 12.1%] in ligamentum tereseinjured group, P < .01) and the apex of the femoral head (anterior apex: 7.1% [grade 1, 3.8%; grade 2, 3.3%] in intact group and 42.4% [grade 1, 30.3%; grade 2, 12.1%] in injured group, P < .01; middle apex: 7.6% [grade 1, 3.8%; grade 2, 3.8%] in intact group and 63.5% [grade 1, 42.4%; grade 2, 18.1%; grade 3, 3.0%] in injured group, P ¼ .04; posterior apex: 7.6% [grade 1, 3.8%; grade 2, 3.8%] in intact group and 42.4% [grade 1, 30.3%; grade 2, 12.1%] in injured group, P < .01). Conclusions: This study showed the association between ligamentum teres injury and articular cartilage damage in the inferior middle part of the acetabulum and the apex of the femoral head in patients treated for femoroacetabular impingement. Level of Evidence: Level IV, case-control study.
E
vidence exists that rupture of the ligamentum teres can be a potential source of hip pain.1-4 In large series of patients undergoing arthroscopy, the incidence of rupture of this ligament varied from 8% to 51%.2,5,6 Such lesions have been cited as the third most common lesion causing hip pain in athletes.7 One prior study reported that hip pain due to ligamentum teres injury can be successfully treated by debridement.2 However, it is our belief that, in some patients, persistent hip pain
From the Department of Orthopedic Surgery, Sapporo Medical University School of Medicine (M.K., T.S., T.Y.), Sapporo, Japan; and Asari Chuo Hospital (T.M.), Otaru, Japan. The authors report that they have no conflicts of interest in the authorship and publication of this article. Received January 28, 2014; accepted June 6, 2014. Address correspondence to Mitsunori Kaya, Department of Orthopedic Surgery, Sapporo Medical University School of Medicine, S-1, W-16, Chuo-ku, Sapporo, Hokkaido, 060-8543, Japan. E-mail: [email protected] Ó 2014 by the Arthroscopy Association of North America 0749-8063/1467/$36.00 http://dx.doi.org/10.1016/j.arthro.2014.06.013
1582
is related to the loss of stability normally provided by the intact ligamentum teres. Rupture of the ligamentum teres often results in instability and poor function of the hip joint.8-11 We believe that continued hip instability may lead to the development of labral tears, osteochondral damage, and eventually, osteoarthritis. However, the effect of ligamentum teres injury on femoroacetabular cartilage damage has not been reported in the literature. The objective of this study was to investigate the association between ligamentum teres injury and the hip joint cartilage damage pattern in patients with femoroacetabular impingement (FAI). Our hypothesis was that ligamentum teres injury might alter the articular cartilage damage pattern in patients with FAI.
Methods All patients were informed about the ongoing study. This study was approved by the institutional review board. We conducted a retrospective review of 128 cases that underwent arthroscopy between April 2011 and December 2013. The inclusion criteria for this study
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 30, No 12 (December), 2014: pp 1582-1587
LIGAMENTUM TERES INJURY
1583
Fig 1. Hip joint cartilage injury assessment form showing right hip zones. For the acetabular zones, 2 vertical lines are drawn using the anterior and posterior notch walls as references. A horizontal line is drawn at the top of the acetabular notch. These lines divide the acetabulum into 6 different zones. Progressive numbers are assigned to each of the zones, starting with number 1 at the anterior-inferior zone. Number 6 is assigned to the acetabular notch. For the femoral head zones, the dashed line indicates the area that corresponds to the acetabular notch. Lines are positioned following the pattern of the lines used for the acetabulum. The numbers are assigned to each zone in a progressive fashion, starting with number 1 at the anterior-inferior head. Number 6 is assigned to the area corresponding to the acetabular notch. Zone 6 contains the ligamentum teres. In the femoral head, zones 2, 3, and 4 are subdivided into 3 areas: medial (M), superior (S), and lateral (L). (Ant, anterior; Dist, distal; Lat, lateral; Med, medial; Post, posterior; Prox, proximal.)
were patients with FAI who underwent arthroscopic surgery. The exclusion criteria were as follows: advanced hip osteoarthritis (grade >2 according to Tönnis classification), hip joint laxity, acetabular dysplasia, and borderline dysplasia. Patients with a positive impingement sign and radiographic parameters consistent with FAI (crossover sign, pistol-grip deformity, and alpha angle >55 ) were diagnosed as having FAI.12,13 Hip joint laxity was defined as a lack of radiologic evidence of FAI but with symptomatic femoroacetabular instability on clinical examination, as shown by a positive hip dial test and axial traction test.14 Patients were diagnosed with acetabular dysplasia if the lateral center-edge angle of Wiberg was less than 25 . Acetabular dysplasia15-18 was subdivided into dysplasia (center-edge angle of Wiberg 2 according to Tönnis classification), hip joint laxity (20 patients), acetabular dysplasia (5 patients), and borderline dysplasia (21 patients) were excluded from this study. The remaining 77 patients with FAI were included in this study. Because all patients with FAI who underwent arthroscopic surgery were enrolled in this study, this is a consecutive series. All arthroscopies were performed by the senior author (M.K.) with the patients in the supine position, by use of 2 portals (anterolateral and midanterior).20 Ligamentum teres tears were observed routinely during all hip arthroscopies, and visual assessment of the presence of torn fibers was performed. A routine
arthroscopic straight probe was used for further examination of the ligaments. Ligamentum teres tears were classified according to the classification system of Gray and Villar.1 The depths of cartilage defects were classified according to the International Cartilage Repair Society (ICRS) grading system21 as follows: superficial, which is a soft indentation or superficial fissures and cracks (ICRS grade 1); a lesion extending to less than half of the cartilage depth (ICRS grade 2); a lesion extending to half or more of the cartilage depth but not into the subchondral bone (ICRS grade 3); or an osteochondral lesion (ICRS grade 4).22,23 The anatomic locations of the defects were outlined by the surgeon (M.K.) on grid maps of the articular surfaces of both the acetabulum and femoral head. For this purpose, the geographic zone method described by Ilizaliturri et al.24 was used (Fig 1). The acetabulum was divided into 6 different zones as follows: anterior inferior (zone 1), anterior superior (zone 2), middle superior (zone 3), posterior superior (zone 4), posterior inferior (zone 5), and middle inferior (zone 6). The same system was applied to the femoral head. The area that corresponded to the acetabular fossa was positioned on the femoral head following the same pattern that was used for the acetabulum. For the head, zones 2, 3, and 4 were subdivided into medial (e.g., zone 2M), superior (e.g., zone 2S), and lateral (e.g., zone 2L) areas. The articular lesions were drawn on chondral maps by the senior author at the completion of arthroscopy. The patients were divided into 2 groups (ligamentum teres, intact
1584
M. KAYA ET AL.
Table 1. Cartilage Injury Distribution in All Patients With Intact Ligamentum Teres (n ¼ 30)
Acetabulum Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 Zone 6 Femoral head Zone 1 Zone 2M Zone 2S Zone 2L Zone 3M Zone 3S Zone 3L Zone 4M Zone 4S Zone 4L Zone 5 Zone 6
Grade 0 (%)
Grade 1 (%)
Grade 2 (%)
Grade 3 (%)
Grade 4 (%)
100.0 19.2 30.7 88.4 96.1 92.3
0 23.0 11.5 3.8 0 7.6
0 3.8 0 3.8 3.8 0
0 26.9 26.9 0 0 0
0 26.9 30.7 3.8 0 0
92.3 88.4 88.4 88.4 96.1 50.0 50.0 96.1 53.8 53.8 92.3 92.3
3.8 7.6 7.6 7.6 0 7.6 3.8 0 3.8 0 3.8 3.8
3.3 0 0 0 3.8 26.9 26.9 3.8 26.9 30.7 3.8 3.8
0 3.8 3.8 3.8 0 11.5 15.3 0 11.5 11.5 0 0
0 0 0 0 0 3.8 3.8 0 3.8 3.8 0 0
group, and injured group), and the incidence of cartilage injury and its degree in each grid were compared. Differences among groups were assessed with the MannWhitney U test. Differences were deemed statistically significant at P < .05. Statistical analysis was performed with SPSS software, version 9.0 (SPSS, Chicago, IL).
Results The patient population consisted of 32 male and 45 female patients with a mean age of 47.5 years (range, 18 to 78 years). No patients had a traumatic history of Table 2. Cartilage Injury Distribution in All Patients With Ruptured Ligamentum Teres (n ¼ 47)
Acetabulum Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 Zone 6 Femoral head Zone 1 Zone 2M Zone 2S Zone 2L Zone 3M Zone 3S Zone 3L Zone 4M Zone 4S Zone 4L Zone 5 Zone 6
Grade 0 (%)
Grade 1 (%)
Grade 2 (%)
Grade 3 (%)
Grade 4 (%)
100.0 15.1 27.2 93.9 96.9 33.3
0 15.1 12.1 3.0 3.0 12.1
0 6.0 3.0 0 0 42.4
0 18.1 15.1 0 0 12.1
0 45.4 42.4 3.0 0 0
57.5 96.9 96.9 96.9 100 45.4 30.3 100 33.3 36.3 57.5 36.3
30.3 3.0 0 0 0 3.0 9.0 0 21.2 6.0 30.3 42.4
12.1 0 3.0 3.0 0 21.2 21.2 0 21.2 30.3 12.1 18.1
0 0 0 0 0 27.2 33.3 0 18.1 21.2 0 3.0
0 0 0 0 0 3.0 6.0 0 6.0 6.0 0 0
ligamentum teres tear including dislocation of the hip joint or acetabular facture. According to the classification of Gray and Villar,1 20 patients had a complete rupture and 27 had a partial tear. The patients were divided into 2 groups: ligamentum tereseintact group (n ¼ 30) and ligamentum tereseinjured group (n ¼ 47). Tables 1 and 2 present the distribution and grades of cartilage injuries in the ligamentum tereseintact group and ligamentum tereseinjured group, respectively. In the acetabulum (Fig 2), the commonly affected zones were the anterior-superior zone (zone 2) (80.6% in ligamentum tereseintact group and 84.5% in ligamentum tereseinjured group) and the middle-superior zone (zone 3) (69.1% in intact group and 72.6% in injured group). On the femoral head side (Fig 3), the cartilage injuries were centered in the superior to lateral areas of the anterolateral and lateral zones (zone 3S: 49.8% in intact group and 54.4% in injured group; zone 3L: 49.8% in intact group and 69.5% in injured group; zone 4S: 46.0% in intact group and 66.5% in injured group; zone 4L: 46.0% in intact group and 63.5% in injured group). The same tendency for this distribution pattern existed in both groups, between which there was no statistically significant difference. In FAI the most common situation is mixed cam and pincer pathology occurring along the anterior femoral neck and the anterior-superior acetabular rim. As the hip flexes, particularly in internal rotation, the anterolateral region of the femoral head contacts the anteriorsuperior region of the acetabulum. Therefore this chondral damage was considered to be an FAI-specific pathology. In patients with ligamentum teres injury (Fig 4), however, chondral damage was observed even in the middle-inferior area of the acetabulum and at the apex of the femoral head (66.6% in acetabular zone 6, 42.4% in femoral head zone 1, 42.4% in femoral head zone 5, and 63.5% in femoral head zone 6). The differences in the incidences of these lesions were statistically significant (P < .01 in acetabular zone 6, P < .01 in femoral head zone 1, P ¼ .04 in femoral head zone 5, and P < .01 in femoral head zone 6) (Video 1, available at www.arthroscopyjournal.org).
Discussion
The most important finding of our study was that ligamentum teres injury was strongly associated with articular cartilage damage in the inferior middle part of the acetabulum and the apex of the femoral head in addition to FAI-specific chondral damage. This observation has not been previously reported. The role of the ligamentum teres in stabilizing the hip joint has been debated. However, studies have suggested that the ligamentum teres does contribute to hip stability.8,9 Martin et al.8,9 reported that the ligamentum teres might contribute to hip stability when the hip is in flexion/external rotation and extension/internal
LIGAMENTUM TERES INJURY
1585
Fig 2. Comparison of incidences of acetabular cartilage injury. The chondral damage among groups calculated with the Mann-Whitney U test was significantly different in acetabular zone 6 (P < .01). (Ant, anterior; Dist, distal; Post, posterior; Prox, proximal.)
rotation. The movements that bring the hip into these positions are squatting and attempting to cross 1 leg behind the other when standing, respectively. In addition, Martin et al.9 noted that, of 9 patients with a complete ligamentum teres tear, 5 had instability complaints when they were asked to squat. This information supports the idea that the ligamentum teres may be an important stabilizer of the hip joint. Regarding the causality of the articular cartilage damage in the ligamentum tereseinjured hip, a phenomenon similar to what we found in this study has already been reported in the knee joint field. Li et al.25
Fig 3. Comparison of incidences of femoral head cartilage injury. The chondral damage among groups calculated with the Mann-Whitney U test differed significantly in zone 1 (P < .01), zone 5 (P ¼ .04), and zone 6 (P < .01). (Dist, distal; Lat, lateral; Med, medial; Prox, proximal.)
reported the results of their kinematic study of anterior cruciate ligament (ACL)edeficient knees. In the presence of ACL injury, the contact points shift both posteriorly and laterally on the surface of the tibial plateau. In the medial compartment, the contact points shift toward the medial tibial spine, a region where degeneration is observed in patients with chronic ACL injuries. This suggests the possibility that alteration of the tibiofemoral contact points might change contact stress distributions in the cartilage and predispose the joint to degenerative changes. We speculate that a similar scenario in which ligamentum teres tears lead to instability
1586
M. KAYA ET AL.
only evaluated patients with FAI and not patients with ligamentum teres injury alone. This selection bias is another limitation. The lack of other observers or comparison of multiple evaluations of the status of the ligamentum teres injuries is also a limitation. One could have videotaped the diagnostic portion of the arthroscopy and then had 2 observers evaluate the videos and, ideally, view the videos more than once to obtain intraobserver and interobserver comparisons. Whether the results can be replicated is uncertain because there was one surgeon (M.K.) and no independent corroboration. We found particular chondral damage patterns in ligamentum tereseinjured hips. From these findings, the association between chondral damage and ligamentum teres dysfunction can be inferred. However, the causality of the altered articular cartilage damage pattern in the ligamentum tereseinjured hip remains unsolved.
Conclusions This study showed the association between ligamentum teres injury and articular cartilage damage in the inferior middle part of the acetabulum and the apex of the femoral head in patients treated for FAI.
References
Fig 4. Arthroscopic findings of patients with ligamentum teres injury (left hip, from anterolateral portal). (A) Complete rupture of ligamentum teres (arrow) and chondral injury of apex of femoral head. (B) Chondral injury was observed even around the cotyloid fossa.
and in which hip joint instability leads to articular cartilage damage is assumed, although there is no literature at this point to support this speculation. Our results regarding the relation of ligamentum teres injury to degenerative arthritis might have important implications for contemporary ligamentum teres reconstruction with the goal of reducing pain and preventing the progression of early-onset osteoarthritis.10,26-28 However, few studies have reported whether osteochondral lesions persist or progress even after ligamentum teres reconstruction. To investigate whether ligamentum teres reconstruction can not only reproduce normal hip mechanics but also prevent degenerative arthritis is a subject for future analysis. Limitations One limitation of this study is the small sample size of this cohort. However, despite its size, there were consistent results within it, and we would expect this consistency to continue in a larger group. This study
1. Gray AJR, Villar RN. The ligamentum teres of the hip: An arthroscopic classification of its pathology. Arthroscopy 1997;13:575-578. 2. Byrd JW, Jones KS. Traumatic rupture of the ligamentum teres as a source of hip pain. Arthroscopy 2004;20:385-391. 3. Kusuma M, Jung J, Dienst M, Goedde S, Kohn D, Seil R. Arthroscopic treatment of an avulsion fracture of the ligamentum teres of the hip in an 18 year old horse rider. Arthroscopy 2004;20:64-66 (suppl 2). 4. Philippon MJ, Kuppersmith DA, Wolff AB, Briggs KK. Arthroscopic findings following traumatic hip dislocation in 14 professional athletes. Arthroscopy 2009;25:169-174. 5. Botser IB, Martin DE, Stout CE, Domb BG. Tears of the ligamentum teres: Prevalence in hip arthroscopy using 2 classification systems. Am J Sports Med 2011;39:117S-125S (suppl). 6. Villar RN. Hip arthroscopy. Oxford: Butterworth Heineman, 1992. 7. Byrd JW, Jones KS. Hip arthroscopy in athletes. Clin Sports Med 2001;20:749-761. 8. Martin RL, Kivilan BR, Clemente FR. A cadaveric model for ligamentum teres function: A pilot study. Knee Surg Sport Traumatol Arthrosc 2013;21:1689-1693. 9. Martin RL, Palmer I, Martin HD. Ligamentum teres: A functional description and potential clinical relevance. Knee Surg Sport Traumatol Arthrosc 2012;20:1209-1214. 10. Amenabar T, O’Donnell J. Arthroscopic ligamentum teres reconstruction using semitendinosus tendon: Surgical technique and an unusual outcome. Arthrosc Tech 2012;1: e169-e174. 11. O’Donnell J, Economopoulos K, Singh P, Bates D, Pritchard M. The ligamentum teres test. A novel and
LIGAMENTUM TERES INJURY
12.
13.
14.
15.
16. 17.
18.
19.
effective test in diagnosing tears of the ligamentum teres. Am J Sports Med 2014;42:138-143. Lynch TS, Terry MA, Bedi A, Kelly BT. Hip arthroscopic surgery: Patient evaluation, current indications, and outcomes. Am J Sports Med 2013;41:1174-1189. Imam S, Khanduja V. Current concepts in the diagnosis and management of femoroacetabular impingement. Int Orthop 2011;35:1427-1435. Philippon MJ, Falvey E, Verrall GM, Briggs KK. Pain the pelvic, inguinal and hip region. In: Bahr R, ed. The IOC manual of sports injuries. Oxford: Wiley Blackwell, 2012;310-333. Wiberg G. Studies on dysplastic acetabula and congenital subluxation of the hip joint. With special reference to the complication of osteoarthritis. Acta Chir Scand 1939;83:58 (suppl). Fredensborg N. The CE angle of normal hip. Acta Orthop Scand 1976;47:403-405. Delaunay S, Dussault RG, Kaplan PA, Alford BA. Radiologic measurements of dysplastic adult hip. Skeletal Radiol 1997;26:75-81. Nelitz M, Guenther KP, Gunkel S, Puhl W. Reliability of radiological measurements in the assessment of hip dysplasia in adults. Br J Radiol 1999;72:331-334. Domb BG, Stake CE, Lindner D, El-Bitar Y, Jackson TJ. Arthroscopic capsular plication and labral preservation in borderline hip dysplasia. Two-year clinical outcomes of a surgical approach to a challenging problem. Am J Sports Med 2013;41:2591-2598.
1587
20. Philippon MJ, Weiss DR, Kuppersmith DA, Briggs KK, Hay CJ. Arthroscopic labral repair and treatment of femoroacetabular impingement in professional hockey players. Am J Sports Med 2010;38:99-104. 21. International Cartilage Repair Society (ICRS). The cartilage standard evaluation form/knee. ICRS Newsletter. 1998;5-7. 22. Stone KR, Walgenbach A. Surgical technique for articular cartilage transplantation to full-thickness cartilage defects in the knee joint. Oper Tech Orthop 1997;7:305-311. 23. Zamber RW, Teitz CC, McGuire DA, et al. Articular cartilage lesions of the knee. Arthroscopy 1989;5:258-268. 24. Ilizaliturri VM, Byrd JWT, Sampson TG, et al. A geographic zone method to describe intra-articular pathology in hip arthroscopy: Cadaveric study and preliminary report. Arthroscopy 2008;24:534-539. 25. Li G, Moses JM, Papannagari R, Pathare NP, Defrate LE, Gill TJ. Anterior cruciate ligament deficiency alters the in vivo motion of the tibiofemoral cartilage contact points in both the anteroposterior and mediolateral directions. J Bone Joint Surg Am 2006;88:1826-1834. 26. Simpson JM, Field RE, Villar RN. Arthroscopic reconstruction of the ligamentum teres. Arthroscopy 2011;27:436-441. 27. Philippon MJ, Pennock A, Gaskill TR. Arthroscopic reconstruction of the ligamentum teres. J Bone Joint Surg Br 2012;94:1494-1498. 28. Lindner D, Sharp KG, Trenga AP, Stone J, Stake CE, Domb BG. Arthroscopic ligamentum teres reconstruction. Arthrosc Tech 2013;2:e21-e25.
Ligamentum Teres Injury Is Associated With the Articular Damage Pattern in Patients With Femoroacetabular Impingement Mitsunori Kaya, M.D., Tomoyuki Suziki, M.D., Takeshi Minowa, M.D., and Toshihiko Yamashita, M.D.
Purpose: The objective of this study was to investigate the association between ligamentum teres injury and the hip joint cartilage damage pattern in patients with femoroacetabular impingement. Methods: We compared articular cartilage damage between ligamentum tereseintact anderuptured hips. Data were collected for 77 consecutive patients with femoroacetabular impingement who underwent hip arthroscopy. The locations of the chondral lesions were recorded on anatomic articular maps using the geographic zone method. The patients were divided into 2 groups (ligamentum tereseintact andeinjured groups), and the incidence and degree of cartilage injury were compared between the 2 groups by use of the Mann-Whitney U test. Results: In patients with ligamentum teres injury, chondral damage extended to the middle-inferior area of the acetabulum (7.6% [grade 1] in ligamentum tereseintact group and 66.6% [grade 1, 12.1%; grade 2, 42.4%; grade 3, 12.1%] in ligamentum tereseinjured group, P < .01) and the apex of the femoral head (anterior apex: 7.1% [grade 1, 3.8%; grade 2, 3.3%] in intact group and 42.4% [grade 1, 30.3%; grade 2, 12.1%] in injured group, P < .01; middle apex: 7.6% [grade 1, 3.8%; grade 2, 3.8%] in intact group and 63.5% [grade 1, 42.4%; grade 2, 18.1%; grade 3, 3.0%] in injured group, P ¼ .04; posterior apex: 7.6% [grade 1, 3.8%; grade 2, 3.8%] in intact group and 42.4% [grade 1, 30.3%; grade 2, 12.1%] in injured group, P < .01). Conclusions: This study showed the association between ligamentum teres injury and articular cartilage damage in the inferior middle part of the acetabulum and the apex of the femoral head in patients treated for femoroacetabular impingement. Level of Evidence: Level IV, case-control study.
E
vidence exists that rupture of the ligamentum teres can be a potential source of hip pain.1-4 In large series of patients undergoing arthroscopy, the incidence of rupture of this ligament varied from 8% to 51%.2,5,6 Such lesions have been cited as the third most common lesion causing hip pain in athletes.7 One prior study reported that hip pain due to ligamentum teres injury can be successfully treated by debridement.2 However, it is our belief that, in some patients, persistent hip pain
From the Department of Orthopedic Surgery, Sapporo Medical University School of Medicine (M.K., T.S., T.Y.), Sapporo, Japan; and Asari Chuo Hospital (T.M.), Otaru, Japan. The authors report that they have no conflicts of interest in the authorship and publication of this article. Received January 28, 2014; accepted June 6, 2014. Address correspondence to Mitsunori Kaya, Department of Orthopedic Surgery, Sapporo Medical University School of Medicine, S-1, W-16, Chuo-ku, Sapporo, Hokkaido, 060-8543, Japan. E-mail: [email protected] Ó 2014 by the Arthroscopy Association of North America 0749-8063/1467/$36.00 http://dx.doi.org/10.1016/j.arthro.2014.06.013
1582
is related to the loss of stability normally provided by the intact ligamentum teres. Rupture of the ligamentum teres often results in instability and poor function of the hip joint.8-11 We believe that continued hip instability may lead to the development of labral tears, osteochondral damage, and eventually, osteoarthritis. However, the effect of ligamentum teres injury on femoroacetabular cartilage damage has not been reported in the literature. The objective of this study was to investigate the association between ligamentum teres injury and the hip joint cartilage damage pattern in patients with femoroacetabular impingement (FAI). Our hypothesis was that ligamentum teres injury might alter the articular cartilage damage pattern in patients with FAI.
Methods All patients were informed about the ongoing study. This study was approved by the institutional review board. We conducted a retrospective review of 128 cases that underwent arthroscopy between April 2011 and December 2013. The inclusion criteria for this study
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 30, No 12 (December), 2014: pp 1582-1587
LIGAMENTUM TERES INJURY
1583
Fig 1. Hip joint cartilage injury assessment form showing right hip zones. For the acetabular zones, 2 vertical lines are drawn using the anterior and posterior notch walls as references. A horizontal line is drawn at the top of the acetabular notch. These lines divide the acetabulum into 6 different zones. Progressive numbers are assigned to each of the zones, starting with number 1 at the anterior-inferior zone. Number 6 is assigned to the acetabular notch. For the femoral head zones, the dashed line indicates the area that corresponds to the acetabular notch. Lines are positioned following the pattern of the lines used for the acetabulum. The numbers are assigned to each zone in a progressive fashion, starting with number 1 at the anterior-inferior head. Number 6 is assigned to the area corresponding to the acetabular notch. Zone 6 contains the ligamentum teres. In the femoral head, zones 2, 3, and 4 are subdivided into 3 areas: medial (M), superior (S), and lateral (L). (Ant, anterior; Dist, distal; Lat, lateral; Med, medial; Post, posterior; Prox, proximal.)
were patients with FAI who underwent arthroscopic surgery. The exclusion criteria were as follows: advanced hip osteoarthritis (grade >2 according to Tönnis classification), hip joint laxity, acetabular dysplasia, and borderline dysplasia. Patients with a positive impingement sign and radiographic parameters consistent with FAI (crossover sign, pistol-grip deformity, and alpha angle >55 ) were diagnosed as having FAI.12,13 Hip joint laxity was defined as a lack of radiologic evidence of FAI but with symptomatic femoroacetabular instability on clinical examination, as shown by a positive hip dial test and axial traction test.14 Patients were diagnosed with acetabular dysplasia if the lateral center-edge angle of Wiberg was less than 25 . Acetabular dysplasia15-18 was subdivided into dysplasia (center-edge angle of Wiberg 2 according to Tönnis classification), hip joint laxity (20 patients), acetabular dysplasia (5 patients), and borderline dysplasia (21 patients) were excluded from this study. The remaining 77 patients with FAI were included in this study. Because all patients with FAI who underwent arthroscopic surgery were enrolled in this study, this is a consecutive series. All arthroscopies were performed by the senior author (M.K.) with the patients in the supine position, by use of 2 portals (anterolateral and midanterior).20 Ligamentum teres tears were observed routinely during all hip arthroscopies, and visual assessment of the presence of torn fibers was performed. A routine
arthroscopic straight probe was used for further examination of the ligaments. Ligamentum teres tears were classified according to the classification system of Gray and Villar.1 The depths of cartilage defects were classified according to the International Cartilage Repair Society (ICRS) grading system21 as follows: superficial, which is a soft indentation or superficial fissures and cracks (ICRS grade 1); a lesion extending to less than half of the cartilage depth (ICRS grade 2); a lesion extending to half or more of the cartilage depth but not into the subchondral bone (ICRS grade 3); or an osteochondral lesion (ICRS grade 4).22,23 The anatomic locations of the defects were outlined by the surgeon (M.K.) on grid maps of the articular surfaces of both the acetabulum and femoral head. For this purpose, the geographic zone method described by Ilizaliturri et al.24 was used (Fig 1). The acetabulum was divided into 6 different zones as follows: anterior inferior (zone 1), anterior superior (zone 2), middle superior (zone 3), posterior superior (zone 4), posterior inferior (zone 5), and middle inferior (zone 6). The same system was applied to the femoral head. The area that corresponded to the acetabular fossa was positioned on the femoral head following the same pattern that was used for the acetabulum. For the head, zones 2, 3, and 4 were subdivided into medial (e.g., zone 2M), superior (e.g., zone 2S), and lateral (e.g., zone 2L) areas. The articular lesions were drawn on chondral maps by the senior author at the completion of arthroscopy. The patients were divided into 2 groups (ligamentum teres, intact
1584
M. KAYA ET AL.
Table 1. Cartilage Injury Distribution in All Patients With Intact Ligamentum Teres (n ¼ 30)
Acetabulum Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 Zone 6 Femoral head Zone 1 Zone 2M Zone 2S Zone 2L Zone 3M Zone 3S Zone 3L Zone 4M Zone 4S Zone 4L Zone 5 Zone 6
Grade 0 (%)
Grade 1 (%)
Grade 2 (%)
Grade 3 (%)
Grade 4 (%)
100.0 19.2 30.7 88.4 96.1 92.3
0 23.0 11.5 3.8 0 7.6
0 3.8 0 3.8 3.8 0
0 26.9 26.9 0 0 0
0 26.9 30.7 3.8 0 0
92.3 88.4 88.4 88.4 96.1 50.0 50.0 96.1 53.8 53.8 92.3 92.3
3.8 7.6 7.6 7.6 0 7.6 3.8 0 3.8 0 3.8 3.8
3.3 0 0 0 3.8 26.9 26.9 3.8 26.9 30.7 3.8 3.8
0 3.8 3.8 3.8 0 11.5 15.3 0 11.5 11.5 0 0
0 0 0 0 0 3.8 3.8 0 3.8 3.8 0 0
group, and injured group), and the incidence of cartilage injury and its degree in each grid were compared. Differences among groups were assessed with the MannWhitney U test. Differences were deemed statistically significant at P < .05. Statistical analysis was performed with SPSS software, version 9.0 (SPSS, Chicago, IL).
Results The patient population consisted of 32 male and 45 female patients with a mean age of 47.5 years (range, 18 to 78 years). No patients had a traumatic history of Table 2. Cartilage Injury Distribution in All Patients With Ruptured Ligamentum Teres (n ¼ 47)
Acetabulum Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 Zone 6 Femoral head Zone 1 Zone 2M Zone 2S Zone 2L Zone 3M Zone 3S Zone 3L Zone 4M Zone 4S Zone 4L Zone 5 Zone 6
Grade 0 (%)
Grade 1 (%)
Grade 2 (%)
Grade 3 (%)
Grade 4 (%)
100.0 15.1 27.2 93.9 96.9 33.3
0 15.1 12.1 3.0 3.0 12.1
0 6.0 3.0 0 0 42.4
0 18.1 15.1 0 0 12.1
0 45.4 42.4 3.0 0 0
57.5 96.9 96.9 96.9 100 45.4 30.3 100 33.3 36.3 57.5 36.3
30.3 3.0 0 0 0 3.0 9.0 0 21.2 6.0 30.3 42.4
12.1 0 3.0 3.0 0 21.2 21.2 0 21.2 30.3 12.1 18.1
0 0 0 0 0 27.2 33.3 0 18.1 21.2 0 3.0
0 0 0 0 0 3.0 6.0 0 6.0 6.0 0 0
ligamentum teres tear including dislocation of the hip joint or acetabular facture. According to the classification of Gray and Villar,1 20 patients had a complete rupture and 27 had a partial tear. The patients were divided into 2 groups: ligamentum tereseintact group (n ¼ 30) and ligamentum tereseinjured group (n ¼ 47). Tables 1 and 2 present the distribution and grades of cartilage injuries in the ligamentum tereseintact group and ligamentum tereseinjured group, respectively. In the acetabulum (Fig 2), the commonly affected zones were the anterior-superior zone (zone 2) (80.6% in ligamentum tereseintact group and 84.5% in ligamentum tereseinjured group) and the middle-superior zone (zone 3) (69.1% in intact group and 72.6% in injured group). On the femoral head side (Fig 3), the cartilage injuries were centered in the superior to lateral areas of the anterolateral and lateral zones (zone 3S: 49.8% in intact group and 54.4% in injured group; zone 3L: 49.8% in intact group and 69.5% in injured group; zone 4S: 46.0% in intact group and 66.5% in injured group; zone 4L: 46.0% in intact group and 63.5% in injured group). The same tendency for this distribution pattern existed in both groups, between which there was no statistically significant difference. In FAI the most common situation is mixed cam and pincer pathology occurring along the anterior femoral neck and the anterior-superior acetabular rim. As the hip flexes, particularly in internal rotation, the anterolateral region of the femoral head contacts the anteriorsuperior region of the acetabulum. Therefore this chondral damage was considered to be an FAI-specific pathology. In patients with ligamentum teres injury (Fig 4), however, chondral damage was observed even in the middle-inferior area of the acetabulum and at the apex of the femoral head (66.6% in acetabular zone 6, 42.4% in femoral head zone 1, 42.4% in femoral head zone 5, and 63.5% in femoral head zone 6). The differences in the incidences of these lesions were statistically significant (P < .01 in acetabular zone 6, P < .01 in femoral head zone 1, P ¼ .04 in femoral head zone 5, and P < .01 in femoral head zone 6) (Video 1, available at www.arthroscopyjournal.org).
Discussion
The most important finding of our study was that ligamentum teres injury was strongly associated with articular cartilage damage in the inferior middle part of the acetabulum and the apex of the femoral head in addition to FAI-specific chondral damage. This observation has not been previously reported. The role of the ligamentum teres in stabilizing the hip joint has been debated. However, studies have suggested that the ligamentum teres does contribute to hip stability.8,9 Martin et al.8,9 reported that the ligamentum teres might contribute to hip stability when the hip is in flexion/external rotation and extension/internal
LIGAMENTUM TERES INJURY
1585
Fig 2. Comparison of incidences of acetabular cartilage injury. The chondral damage among groups calculated with the Mann-Whitney U test was significantly different in acetabular zone 6 (P < .01). (Ant, anterior; Dist, distal; Post, posterior; Prox, proximal.)
rotation. The movements that bring the hip into these positions are squatting and attempting to cross 1 leg behind the other when standing, respectively. In addition, Martin et al.9 noted that, of 9 patients with a complete ligamentum teres tear, 5 had instability complaints when they were asked to squat. This information supports the idea that the ligamentum teres may be an important stabilizer of the hip joint. Regarding the causality of the articular cartilage damage in the ligamentum tereseinjured hip, a phenomenon similar to what we found in this study has already been reported in the knee joint field. Li et al.25
Fig 3. Comparison of incidences of femoral head cartilage injury. The chondral damage among groups calculated with the Mann-Whitney U test differed significantly in zone 1 (P < .01), zone 5 (P ¼ .04), and zone 6 (P < .01). (Dist, distal; Lat, lateral; Med, medial; Prox, proximal.)
reported the results of their kinematic study of anterior cruciate ligament (ACL)edeficient knees. In the presence of ACL injury, the contact points shift both posteriorly and laterally on the surface of the tibial plateau. In the medial compartment, the contact points shift toward the medial tibial spine, a region where degeneration is observed in patients with chronic ACL injuries. This suggests the possibility that alteration of the tibiofemoral contact points might change contact stress distributions in the cartilage and predispose the joint to degenerative changes. We speculate that a similar scenario in which ligamentum teres tears lead to instability
1586
M. KAYA ET AL.
only evaluated patients with FAI and not patients with ligamentum teres injury alone. This selection bias is another limitation. The lack of other observers or comparison of multiple evaluations of the status of the ligamentum teres injuries is also a limitation. One could have videotaped the diagnostic portion of the arthroscopy and then had 2 observers evaluate the videos and, ideally, view the videos more than once to obtain intraobserver and interobserver comparisons. Whether the results can be replicated is uncertain because there was one surgeon (M.K.) and no independent corroboration. We found particular chondral damage patterns in ligamentum tereseinjured hips. From these findings, the association between chondral damage and ligamentum teres dysfunction can be inferred. However, the causality of the altered articular cartilage damage pattern in the ligamentum tereseinjured hip remains unsolved.
Conclusions This study showed the association between ligamentum teres injury and articular cartilage damage in the inferior middle part of the acetabulum and the apex of the femoral head in patients treated for FAI.
References
Fig 4. Arthroscopic findings of patients with ligamentum teres injury (left hip, from anterolateral portal). (A) Complete rupture of ligamentum teres (arrow) and chondral injury of apex of femoral head. (B) Chondral injury was observed even around the cotyloid fossa.
and in which hip joint instability leads to articular cartilage damage is assumed, although there is no literature at this point to support this speculation. Our results regarding the relation of ligamentum teres injury to degenerative arthritis might have important implications for contemporary ligamentum teres reconstruction with the goal of reducing pain and preventing the progression of early-onset osteoarthritis.10,26-28 However, few studies have reported whether osteochondral lesions persist or progress even after ligamentum teres reconstruction. To investigate whether ligamentum teres reconstruction can not only reproduce normal hip mechanics but also prevent degenerative arthritis is a subject for future analysis. Limitations One limitation of this study is the small sample size of this cohort. However, despite its size, there were consistent results within it, and we would expect this consistency to continue in a larger group. This study
1. Gray AJR, Villar RN. The ligamentum teres of the hip: An arthroscopic classification of its pathology. Arthroscopy 1997;13:575-578. 2. Byrd JW, Jones KS. Traumatic rupture of the ligamentum teres as a source of hip pain. Arthroscopy 2004;20:385-391. 3. Kusuma M, Jung J, Dienst M, Goedde S, Kohn D, Seil R. Arthroscopic treatment of an avulsion fracture of the ligamentum teres of the hip in an 18 year old horse rider. Arthroscopy 2004;20:64-66 (suppl 2). 4. Philippon MJ, Kuppersmith DA, Wolff AB, Briggs KK. Arthroscopic findings following traumatic hip dislocation in 14 professional athletes. Arthroscopy 2009;25:169-174. 5. Botser IB, Martin DE, Stout CE, Domb BG. Tears of the ligamentum teres: Prevalence in hip arthroscopy using 2 classification systems. Am J Sports Med 2011;39:117S-125S (suppl). 6. Villar RN. Hip arthroscopy. Oxford: Butterworth Heineman, 1992. 7. Byrd JW, Jones KS. Hip arthroscopy in athletes. Clin Sports Med 2001;20:749-761. 8. Martin RL, Kivilan BR, Clemente FR. A cadaveric model for ligamentum teres function: A pilot study. Knee Surg Sport Traumatol Arthrosc 2013;21:1689-1693. 9. Martin RL, Palmer I, Martin HD. Ligamentum teres: A functional description and potential clinical relevance. Knee Surg Sport Traumatol Arthrosc 2012;20:1209-1214. 10. Amenabar T, O’Donnell J. Arthroscopic ligamentum teres reconstruction using semitendinosus tendon: Surgical technique and an unusual outcome. Arthrosc Tech 2012;1: e169-e174. 11. O’Donnell J, Economopoulos K, Singh P, Bates D, Pritchard M. The ligamentum teres test. A novel and
LIGAMENTUM TERES INJURY
12.
13.
14.
15.
16. 17.
18.
19.
effective test in diagnosing tears of the ligamentum teres. Am J Sports Med 2014;42:138-143. Lynch TS, Terry MA, Bedi A, Kelly BT. Hip arthroscopic surgery: Patient evaluation, current indications, and outcomes. Am J Sports Med 2013;41:1174-1189. Imam S, Khanduja V. Current concepts in the diagnosis and management of femoroacetabular impingement. Int Orthop 2011;35:1427-1435. Philippon MJ, Falvey E, Verrall GM, Briggs KK. Pain the pelvic, inguinal and hip region. In: Bahr R, ed. The IOC manual of sports injuries. Oxford: Wiley Blackwell, 2012;310-333. Wiberg G. Studies on dysplastic acetabula and congenital subluxation of the hip joint. With special reference to the complication of osteoarthritis. Acta Chir Scand 1939;83:58 (suppl). Fredensborg N. The CE angle of normal hip. Acta Orthop Scand 1976;47:403-405. Delaunay S, Dussault RG, Kaplan PA, Alford BA. Radiologic measurements of dysplastic adult hip. Skeletal Radiol 1997;26:75-81. Nelitz M, Guenther KP, Gunkel S, Puhl W. Reliability of radiological measurements in the assessment of hip dysplasia in adults. Br J Radiol 1999;72:331-334. Domb BG, Stake CE, Lindner D, El-Bitar Y, Jackson TJ. Arthroscopic capsular plication and labral preservation in borderline hip dysplasia. Two-year clinical outcomes of a surgical approach to a challenging problem. Am J Sports Med 2013;41:2591-2598.
1587
20. Philippon MJ, Weiss DR, Kuppersmith DA, Briggs KK, Hay CJ. Arthroscopic labral repair and treatment of femoroacetabular impingement in professional hockey players. Am J Sports Med 2010;38:99-104. 21. International Cartilage Repair Society (ICRS). The cartilage standard evaluation form/knee. ICRS Newsletter. 1998;5-7. 22. Stone KR, Walgenbach A. Surgical technique for articular cartilage transplantation to full-thickness cartilage defects in the knee joint. Oper Tech Orthop 1997;7:305-311. 23. Zamber RW, Teitz CC, McGuire DA, et al. Articular cartilage lesions of the knee. Arthroscopy 1989;5:258-268. 24. Ilizaliturri VM, Byrd JWT, Sampson TG, et al. A geographic zone method to describe intra-articular pathology in hip arthroscopy: Cadaveric study and preliminary report. Arthroscopy 2008;24:534-539. 25. Li G, Moses JM, Papannagari R, Pathare NP, Defrate LE, Gill TJ. Anterior cruciate ligament deficiency alters the in vivo motion of the tibiofemoral cartilage contact points in both the anteroposterior and mediolateral directions. J Bone Joint Surg Am 2006;88:1826-1834. 26. Simpson JM, Field RE, Villar RN. Arthroscopic reconstruction of the ligamentum teres. Arthroscopy 2011;27:436-441. 27. Philippon MJ, Pennock A, Gaskill TR. Arthroscopic reconstruction of the ligamentum teres. J Bone Joint Surg Br 2012;94:1494-1498. 28. Lindner D, Sharp KG, Trenga AP, Stone J, Stake CE, Domb BG. Arthroscopic ligamentum teres reconstruction. Arthrosc Tech 2013;2:e21-e25.
