- Email: [email protected]
Paediatric First-Time Patella Dislocators: An Approach to Conservative Management
Journal of Orthopaedics, Trauma and Rehabilitation 23 (2017) 30e33
Contents lists available at ScienceDirect
Journal of Orthopaedics, Trauma and Rehabilitation Journal homepages: www.e-jotr.com & www.ejotr.org
Research Paper
Paediatric First-Time Patella Dislocators: An Approach to Conservative Management 兒科首次髕骨脫位 : 保守治療進路 Lam Kai Yet*, Looi Collin, Mahadev Arjandas Department of Orthopaedic Surgery, KK Women's and Children's Hospital (KKH), Singapore, Singapore
a r t i c l e i n f o
a b s t r a c t
Article history: Received 2 November 2015 Received in revised form 24 January 2016 Accepted 16 October 2016
Background: First-time lateral patella dislocations are generally treated nonoperatively. However, the ideal form of conservative management and immobilization remains unknown. We compare the clinical outcomes after different immobilization methods. Methods: Paediatric-age patients that met our inclusion criteria, and presenting with a first episode of lateral patella dislocation to our hospital from 2006 to 2013, were enrolled. Different immobilization methods included brace, backslab, or cylinder cast. A retrospective review was performed to compare bracing against other immobilization methods, using a primary outcome measure of redislocation rate, and secondary outcome measures like progression to surgery, range-of-motion, pain, and weight-bearing status. Results: A total of 142 patients (with 147 affected knees) with minimum 1-year follow-up were included in the study. Bracing was found to be superior to other immobilization methods in preventing repeat dislocations, and need for subsequent surgery. At 6 weeks, patients treated with the backslab had the highest incidence of pain. There were no differences with regards to range-of-motion or weight-bearing status. Conclusion: We recommend the use of a brace, with a progressive rehabilitation protocol in the management of first-time lateral patella dislocators. This study is also unique, in that it specifically addresses nonoperative management of first time patella dislocators in a paediatric-age population group.
Keywords: brace conservative paediatric patella dislocations patella instability
中 文 摘 要 背景: 治療第一次側髕骨脫位通常是採用非手術的保守治療。然而,什麼是最理想的保守治療方案和固定的方 法仍然未知。我們比較了不同固定的方法的臨床效果。 材料和方法: 研究包括了符合我們的納入標準,並在 2006 年至 2013 年間因第一次外側髕骨脫位需要到我們醫 院接受治療的兒童患者。不同的固定方法包括支架(Brace)、 背托(Backslab) 或圓柱石膏繃帶(Cylinder Cast)。我們回顧性地比較了支架和其他固定方法的分別,主要結果指標是再脫位率,次要結果指標是:進行後續 手術比率、關節活動範圍、疼痛分數和負重狀態。 結果: 納入了142 例 (147 受影響膝蓋),隨訪期至少一年。支架被發現在再脫位率和進行後續手術比率兩方面 優勝於其他固定方法。在 6 個星期,接受背托治療的患者的疼痛發生率最高。在關節活動範圍和負重狀態則沒 有分別。 結論: 我們建議使用支架,配合逐步康復訓練,來治療第一次側髕骨脫位的患者。這項研究也非常獨特,因為它明 確地指出在兒童患者上使用保守治療的果效。
Introduction Acute patella dislocation is a common injury encountered in the paediatric population. Incidence is 5.8/100,000 individuals, with a peak incidence of 29/100,000 individuals in the 10e17 year-old age group.1
* Corresponding author. E-mail: [email protected].
With the exception of specific circumstances, like the presence of a loose osteochondral fragment or a large avulsion fracture, firsttime patella dislocations (FTPDs) are usually treated nonoperatively. This is due to several prospective studies over the past few years showing similar outcomes of operative versus nonoperative management.2e5 However, despite this knowledge, there has been a relative lack of research with regards to the ideal type of nonoperative treatment of first time patella dislocators. The evidence at present is
http://dx.doi.org/10.1016/j.jotr.2016.10.004 2210-4917/Copyright © 2017, Hong Kong Orthopaedic Association and the Hong Kong College of Orthopaedic Surgeons. Published by Elsevier (Singapore) Pte Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
K.Y. Lam et al. / Journal of Orthopaedics, Trauma and Rehabilitation 23 (2017) 30e33
scarce and conflicting. Maenpaa and Lehto6 suggested that a posterior splint was superior to cylinder casting or bracing. Rood et al7 found taping to be superior to the cylinder cast. Even meta-analyses have been unable to answer this question, as the immobilization methods and durations vary greatly between studies.8,9 Furthermore, these studies were conducted in a mixed, but predominantly adult population. This is surprising, since the highest incidence of FTPDs occur in the teenage years.1 Our study compares the outcomes between different forms of immobilization used in the treatment of FTPDs in a paediatric population. Methods The hospital Institutional Review Board approved this study. All patients who presented to our hospital for patella dislocations between January 2006 and August 2013 were assessed. Inclusion criteria include the following: (1) age 17 years; (2) an acute episode of patella dislocation (defined as: definite dislocation as identified by attending physician or paramedic or definite dislocation seen on X-rays or patella dislocation requiring manual relocation, with significant pain and swelling post reduction); and (3) first episode on the affected knee. Exclusion criteria include the following: (1) neuromuscular abnormalities; and (2) syndromic (e.g., Down's syndrome, Marfan's syndrome, Nail-patella syndrome); and (3) congenital or habitual patella dislocations. Case notes and online radiographic images of patients who met the study criteria were reviewed. After reduction of the dislocation, all study participants were treated with a backslab (Plaster of Paris) for a week. During the outpatient clinic review at 1 week, each patient was further immobilized in one of the following ways: (1) backslab (fiberglass material) in approximately 10 degrees of flexion for another 3 weeks; (2) cylindrical cast (fiberglass material) in slight flexion for another 3 weeks; and (3) knee brace (Breg T scope Premier PostOp Knee Brace) for another 6 weeks, with a stepwise increase in the maximal allowed range-of-motion. Range-of-motion from 0 to 30 was permitted in the first 2 weeks. This was increased to 60 in the next 2 weeks, and 90 subsequently. All patients were allowed to ambulate as tolerated on crutches. Patients were assessed for presence of significant pain, weightbearing status, and ability to attain full range-of-motion at 6 weeks. After the period of immobilization, the patients were continued on physiotherapy with progressive strengthening exercises. All patients were followed up for a minimum period of 1 year, and any episodes of recurrent dislocation and progression to surgery noted. Statistical analysis was performed using SPSS version 19.0 (IBM Corp. Released 2010. IBM SPSS Statistics for Windows, Version 19.0. Armonk, NY: IBM Corp.). Chi-square test was performed for the comparison of treatment outcomes. Analysis of continuous data was performed through the ANOVA test. A p value < 0.05 is considered significant. Results A total of 142 patients (with 147 knees) met the inclusion and exclusion criteria, and were included in the study. The demographics of our study participants are shown in Table 1. The mean age for FTPDs in our study was 13.8 years old. There was a slight predilection for females (56.3%) and for the left knee (54.9%), although this was not statistically significant. It is of interest to note that there was an increased incidence in the Indian race (23.9%), as compared to their representation in the general population (9.1%).
31
Of the 147 knees that were treated, 105 knees (71.4%) were treated in the brace protocol. Another 13 knees (8.8%) and 29 knees (19.7%) were immobilized in backslab and in cast, respectively. Demographics of the patients treated with the different immobilization methods were comparable. The overall redislocation rate in our study was 16.3%. Table 2 shows a summary of various outcome measures. Use of the brace significantly reduced redislocation rates (8.6%) as opposed to the use of backslab [46.2%, relative risk (RR) 5.18] and cylindrical cast (16.3%, RR 3.60). This also translated to significantly lower surgical rates with use of a brace (4.8%), as compared to the use of backslab (30.8%, RR 6.22). Surgical rates were not lowered significantly when compared against the use of a cylindrical cast. During the assessment at 6 weeks postinjury, all patients were assessed for presence of pain, any limitation of range-of-motion, and weight-bearing status. Those treated with a backslab were significantly more likely to be still in pain (RR 3.24). There was no statistical difference between range-of-motion or weight-bearing status between the three groups. Discussion Despite all the recent advances in the understanding of patellofemoral pathology, there remains until date, a lack of high-level research data that help us answer two simple questions: (1) is immobilization necessary; and (2) if so, which form of immobilization is superior? Immobilization or early mobilization Traditional teaching has been to manage first-time patella dislocators in a cylinder cast for 6 weeks duration.11 This period of immobilization allows the soft tissues (including the medial retinaculum) to heal, repair, and fibrose. Advocators of early mobilization believe that a period of immobilization would result in muscle atrophy, with secondary effects on joint proprioception, pain sensation and joint contractures. Two recent meta-analyses in 20108 and 20129 could not give us conclusive answers due to a paucity of literature. After thorough literature searches, Smith identified only two studies that met their inclusion criteria,6,12 and van Gemert et al9 found an article by Maenpaa and Lehto6 (1997) to be the only study that met theirs. Smith's conclusion in his review article was that there was insufficient evidence in size and quality to justify the use of immobilization following a lateral patellar dislocation. The group from Northampton has attempted to address this question with a pilot feasibility study.13 Although they showed a trend towards superior short-term functional outcomes for those not immobilized, their study, unfortunately, recruited only eight study participants, and was unable to provide statistical evaluation. Sillanpaa14 in Arthroscopy 2011 compared immobilization against free range-of-motion in a knee brace prospectively. They found that early mobilization with the help of a knee brace did not increase recurrent dislocations, and instead, improved the return of range-of-motion. Without higher-level evidence emerging, our opinion is that first-time patella dislocators should still be managed with initial controlled immobilization. Which form of immobilization Several immobilization techniques exist. These range from cylinder casts, to posterior splints (backslab), knee braces, to patella taping. The ideal immobilization technique has not been identified. An article by Maenpaa and Lehto6 showed that the posterior splint
32
K.Y. Lam et al. / Journal of Orthopaedics, Trauma and Rehabilitation 23 (2017) 30e33
Table 1 Demographics and radiographic measurements of participants
Number of patients Number of knees Age at diagnosis (y) Minimum Maximum Mean Gender Male Female Side Right Left Race (2013 statistics10) Chinese (74.2%) Malay (13.3%) Indian (9.1%) Others (3.3%) Radiographic measurements Insall-Salvati ratio (mean) Sulcus Angle (mean) Patella Tilt angle (mean)
Brace
Backslab
Cast
Total
101 (71.1%) 105 (71.4%)
13 (9.2%) 13 (8.8%)
28 (19.7%) 29 (19.7%)
142 147
p
8.08 17.33 13.96
11.25 16.25 13.6
8.58 15.5 13.47
8.08 17.33 13.83
0.31
46 55
4 9
12 16
62 (43.7%) 80 (56.3%)
0.6
50 55
4 9
12 17
66 (45.1%) 81 (54.9%)
0.47
58 13 25 5
6 3 4 0
18 3 5 2
82 (57.7%) 19 (13.4%) 34 (23.9%) 7 (4.9%)
0.78
1.42 139.8 17.4
1.48 137.5 14
1.43 144.2 18
1.43 140.2 17.2
0.68 0.26 0.21
Table 2 Comparison of treatment outcomes Brace
Backslab
Cast
Total
p
Redislocation No Yes (Relative risk with 95% CI)
96 (91.4%) 9 (8.6%) 1.00
7 (53.8%) 6 (46.2%) 5.18 (2.20e12.20)
20 (69.0%) 9 (31.0%) 3.60 (1.58e8.22)
123 (83.7%) 24 (16.3%)
0.00
Surgery No Yes (Relative risk with 95% CI)
100 (95.2%) 5 (4.8%) 1.00
9 (69.2%) 4 (30.8%) 6.22 (1.91e20.25)
27 (93.1%) 2 (6.9%) 1.44 (0.30e7.04)
136 (92.5%) 11 (7.5%)
0.00
Range-of-motion Full Limited (Relative risk with 95% CI)
95 (90.5%) 10 (9.5%) 1.00
10 (76.9%) 3 (23.1%) 2.33 (0.74e7.39)
27 (93.1%) 2 (6.9%) 0.72 (0.17e3.10)
132 (89.8%) 15 (10.2%)
0.25
Pain No Yes (Relative risk with 95% CI)
93 (88.6%) 12 (11.4%) 1.00
8 (61.5%) 5 (38.5%) 3.24 (1.36e7.72)
25 (86.2%) 4 (13.8%) 1.20 (0.42e3.44)
126 (85.7%) 21 (14.3%)
0.03
Weight bearing status Full Partial Non
97 (92.4%) 3 (2.9%) 5 (4.8%)
10 (76.9%) 2 (15.4%) 1 (7.7%)
26 (89.7%) 1 (3.4%) 2 (6.9%)
133 (90.5%) 6 (4.1%) 8 (5.4%)
0.28
may be superior to a cylinder cast and brace. However, critique of this study by van Gemert et al9 was that “the evidence remains low because of the small study population, difference in immobilization duration between groups, use of old braces, and limitations in the study design.” Smith et al8 in their review paper also stated that “there does not appear to be a statistically significant difference in respect to recurrent dislocation rates between immobilizing patients in a cylinder cast, posterior splint, or an elastic bandage”. Rood et al7compared the use of patella taping with cylindrical casting in patients above the age of 18 years, and found significantly better Lysholm scores at 6 weeks, 12 weeks, and 5 years postdislocation. In summary, the evidence supporting the various forms of immobilization is still conflicting. In addition, the majority of these studies were in a mixed (but predominantly adult) population. The
current available literature is unable to address the questions that we have on FTPDs in the paediatric age group. Our study shows that the use of a knee brace with a controlled immobilization protocol allows lower redislocation and surgical rates, and also avoids the problems of limited range-of-motion and persistent pain. Redislocation rate in our brace group was 8.6%. This is lower than the 10e44% often quoted for FTPDs. We believe that keeping our patients in a knee brace allows controlled increase in the range-of-motion. This prevents repeat dislocations due to uncontrolled knee joint motion, and still allows controlled early mobilization. A major drawback of this study is its retrospective nature. As with all retrospective studies, the quality of data collected is not ideal. At the 6 week assessment, we could not quantify the degree of rangeof-motion, or the degree of pain experienced. There were also no functional scores available for assessment. The duration of
K.Y. Lam et al. / Journal of Orthopaedics, Trauma and Rehabilitation 23 (2017) 30e33
immobilization also varied between the groups. For the cast and backslab group, the total immobilization period was for 4 weeks. We believe that any longer periods of casting or backslab immobilization would result in significant stiffness, which would be detrimental during the rehabilitation process. Using the brace, we could allow progressive range-of-motion, and this allowed us to use the brace for a duration of 6 week, without fear of excessive knee stiffness. Another criticism of this study is the large proportion of patients who were treated in brace. This observation is due to the fact that our department has been almost exclusively using the brace protocol in recent years. The decision behind this is that we had noted significant benefits from our earlier experience, as compared to the other immobilisation methods. The relatively smaller number of patients in the comparison groups resulted in wide confidence intervals during statistical analysis. Despite this, the benefit of the brace did reach statistical significance for lowered redislocation rates when compared to the backslab and cast groups, and for lowered surgical rates when compared to the backslab group. A prospective study may help to identify the ideal immobilization method in FTPDs more definitively. Conclusion Despite the drawbacks, our study is unique in that it compares the outcomes of various forms of nonoperative treatment of FTPDs in a paediatric population. We think this is relevant, as most incidences of FTPDs occur in this age group. We recommend the use of a knee brace, with a controlled immobilization protocol, for the nonoperative treatment of FTPDs in the paediatric age group. Conflicts of interest The authors have no conflicts of interest to declare. Funding/support No funding/financial support is received for this study.
33
Acknowledgements The authors acknowledge the help of senior physiotherapist Ms. Ng Shin Huey during the data collection process.
References 1. Fithian DC, Paxton WE, Stone ML, et al. Epidemiology and natural history of acute patellar dislocation. Am J Sports Med 2004;32:1114e21. 2. Palmu SBM, Kallio PE, Donell ST, et al. Acute patellar dislocation in children and adolescents: a randomized clinical trial. J Bone Joint Surg Am 2008;90: 463e70. 3. Stefancin JJ, Parker RD. First-time traumatic patellar dislocation. A systematic review. Clin Orthop Relat Res 2007;455:93e101. 4. Nikku R, Nietosvaara Y, Kallio PE, et al. Operative versus closed treatment of primary dislocation of the patella: similar 2-year results in 125 randomized patients. Acta Orthop Scand 1997;68:419e23. 5. Nikku R, Nietosvaara Y, Aalto K, et al. Operative treatment of primary patellar dislocation does not improve medium term outcome: a 7-year followup report and risk analysis of 127 randomized patients. Acta Orthop 2005;76: 699e704. 6. Maenpaa H, Lehto MU. Patellar dislocation. The long-term results of nonoperative management in 100 patients. Am J Sports Med 1997;25:213e7. 7. Rood A, Boons H, Ploegmakers J, et al. Tape versus cast for non-operative treatment of primary patellar dislocation: a randomized controlled trial. Arch Orthop Trauma Surg 2012;132:1199e203. 8. Smith TO, Davies L, Donell ST. Immobilization regime following lateral patellar dislocation: a systematic review and meta-analysis of the current evidence base. Eur J Trauma Emerg Surg 2010;4:353e60. 9. Van Gemert JP, de Vree LM, Hessels RAPA, et al. Patellar dislocation: cylinder cast, splint or brace? An evidence-based review of the literature. Int J Emerg Med 2012;5:45. 10. Population Trends 2013. Department of Statistics Singapore. www.singstat.gov. sg. 11. Hughston JC. Subluxation of the patella. J Bone Joint Surg Am 1968;50:1003e26. 12. Kiviluoto O, Pasila M, Santavirta S, et al. Recurrences after conservative treatment of acute dislocation of the patella. Italian J Sport Traumatol 1986;3: 159e62. 13. Armstrong BA, Hall M, Crawfurd E, et al. A feasibility study for a pragmatic randomized controlled trial comparing immobilization versus no immobilization for patients following first-time patellar dislocation. Knee 2012;19: 696e702. 14. Sillanpaa PJ, Maenpaa HM, Paakkala A. A prospective randomized study comparing non-operative treatment with and without knee immobilization for primary traumatic patellar dislocation. Arthroscopy e J Arthroscopic Relat Surg 2011;27:e183e4.
Contents lists available at ScienceDirect
Journal of Orthopaedics, Trauma and Rehabilitation Journal homepages: www.e-jotr.com & www.ejotr.org
Research Paper
Paediatric First-Time Patella Dislocators: An Approach to Conservative Management 兒科首次髕骨脫位 : 保守治療進路 Lam Kai Yet*, Looi Collin, Mahadev Arjandas Department of Orthopaedic Surgery, KK Women's and Children's Hospital (KKH), Singapore, Singapore
a r t i c l e i n f o
a b s t r a c t
Article history: Received 2 November 2015 Received in revised form 24 January 2016 Accepted 16 October 2016
Background: First-time lateral patella dislocations are generally treated nonoperatively. However, the ideal form of conservative management and immobilization remains unknown. We compare the clinical outcomes after different immobilization methods. Methods: Paediatric-age patients that met our inclusion criteria, and presenting with a first episode of lateral patella dislocation to our hospital from 2006 to 2013, were enrolled. Different immobilization methods included brace, backslab, or cylinder cast. A retrospective review was performed to compare bracing against other immobilization methods, using a primary outcome measure of redislocation rate, and secondary outcome measures like progression to surgery, range-of-motion, pain, and weight-bearing status. Results: A total of 142 patients (with 147 affected knees) with minimum 1-year follow-up were included in the study. Bracing was found to be superior to other immobilization methods in preventing repeat dislocations, and need for subsequent surgery. At 6 weeks, patients treated with the backslab had the highest incidence of pain. There were no differences with regards to range-of-motion or weight-bearing status. Conclusion: We recommend the use of a brace, with a progressive rehabilitation protocol in the management of first-time lateral patella dislocators. This study is also unique, in that it specifically addresses nonoperative management of first time patella dislocators in a paediatric-age population group.
Keywords: brace conservative paediatric patella dislocations patella instability
中 文 摘 要 背景: 治療第一次側髕骨脫位通常是採用非手術的保守治療。然而,什麼是最理想的保守治療方案和固定的方 法仍然未知。我們比較了不同固定的方法的臨床效果。 材料和方法: 研究包括了符合我們的納入標準,並在 2006 年至 2013 年間因第一次外側髕骨脫位需要到我們醫 院接受治療的兒童患者。不同的固定方法包括支架(Brace)、 背托(Backslab) 或圓柱石膏繃帶(Cylinder Cast)。我們回顧性地比較了支架和其他固定方法的分別,主要結果指標是再脫位率,次要結果指標是:進行後續 手術比率、關節活動範圍、疼痛分數和負重狀態。 結果: 納入了142 例 (147 受影響膝蓋),隨訪期至少一年。支架被發現在再脫位率和進行後續手術比率兩方面 優勝於其他固定方法。在 6 個星期,接受背托治療的患者的疼痛發生率最高。在關節活動範圍和負重狀態則沒 有分別。 結論: 我們建議使用支架,配合逐步康復訓練,來治療第一次側髕骨脫位的患者。這項研究也非常獨特,因為它明 確地指出在兒童患者上使用保守治療的果效。
Introduction Acute patella dislocation is a common injury encountered in the paediatric population. Incidence is 5.8/100,000 individuals, with a peak incidence of 29/100,000 individuals in the 10e17 year-old age group.1
* Corresponding author. E-mail: [email protected].
With the exception of specific circumstances, like the presence of a loose osteochondral fragment or a large avulsion fracture, firsttime patella dislocations (FTPDs) are usually treated nonoperatively. This is due to several prospective studies over the past few years showing similar outcomes of operative versus nonoperative management.2e5 However, despite this knowledge, there has been a relative lack of research with regards to the ideal type of nonoperative treatment of first time patella dislocators. The evidence at present is
http://dx.doi.org/10.1016/j.jotr.2016.10.004 2210-4917/Copyright © 2017, Hong Kong Orthopaedic Association and the Hong Kong College of Orthopaedic Surgeons. Published by Elsevier (Singapore) Pte Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
K.Y. Lam et al. / Journal of Orthopaedics, Trauma and Rehabilitation 23 (2017) 30e33
scarce and conflicting. Maenpaa and Lehto6 suggested that a posterior splint was superior to cylinder casting or bracing. Rood et al7 found taping to be superior to the cylinder cast. Even meta-analyses have been unable to answer this question, as the immobilization methods and durations vary greatly between studies.8,9 Furthermore, these studies were conducted in a mixed, but predominantly adult population. This is surprising, since the highest incidence of FTPDs occur in the teenage years.1 Our study compares the outcomes between different forms of immobilization used in the treatment of FTPDs in a paediatric population. Methods The hospital Institutional Review Board approved this study. All patients who presented to our hospital for patella dislocations between January 2006 and August 2013 were assessed. Inclusion criteria include the following: (1) age 17 years; (2) an acute episode of patella dislocation (defined as: definite dislocation as identified by attending physician or paramedic or definite dislocation seen on X-rays or patella dislocation requiring manual relocation, with significant pain and swelling post reduction); and (3) first episode on the affected knee. Exclusion criteria include the following: (1) neuromuscular abnormalities; and (2) syndromic (e.g., Down's syndrome, Marfan's syndrome, Nail-patella syndrome); and (3) congenital or habitual patella dislocations. Case notes and online radiographic images of patients who met the study criteria were reviewed. After reduction of the dislocation, all study participants were treated with a backslab (Plaster of Paris) for a week. During the outpatient clinic review at 1 week, each patient was further immobilized in one of the following ways: (1) backslab (fiberglass material) in approximately 10 degrees of flexion for another 3 weeks; (2) cylindrical cast (fiberglass material) in slight flexion for another 3 weeks; and (3) knee brace (Breg T scope Premier PostOp Knee Brace) for another 6 weeks, with a stepwise increase in the maximal allowed range-of-motion. Range-of-motion from 0 to 30 was permitted in the first 2 weeks. This was increased to 60 in the next 2 weeks, and 90 subsequently. All patients were allowed to ambulate as tolerated on crutches. Patients were assessed for presence of significant pain, weightbearing status, and ability to attain full range-of-motion at 6 weeks. After the period of immobilization, the patients were continued on physiotherapy with progressive strengthening exercises. All patients were followed up for a minimum period of 1 year, and any episodes of recurrent dislocation and progression to surgery noted. Statistical analysis was performed using SPSS version 19.0 (IBM Corp. Released 2010. IBM SPSS Statistics for Windows, Version 19.0. Armonk, NY: IBM Corp.). Chi-square test was performed for the comparison of treatment outcomes. Analysis of continuous data was performed through the ANOVA test. A p value < 0.05 is considered significant. Results A total of 142 patients (with 147 knees) met the inclusion and exclusion criteria, and were included in the study. The demographics of our study participants are shown in Table 1. The mean age for FTPDs in our study was 13.8 years old. There was a slight predilection for females (56.3%) and for the left knee (54.9%), although this was not statistically significant. It is of interest to note that there was an increased incidence in the Indian race (23.9%), as compared to their representation in the general population (9.1%).
31
Of the 147 knees that were treated, 105 knees (71.4%) were treated in the brace protocol. Another 13 knees (8.8%) and 29 knees (19.7%) were immobilized in backslab and in cast, respectively. Demographics of the patients treated with the different immobilization methods were comparable. The overall redislocation rate in our study was 16.3%. Table 2 shows a summary of various outcome measures. Use of the brace significantly reduced redislocation rates (8.6%) as opposed to the use of backslab [46.2%, relative risk (RR) 5.18] and cylindrical cast (16.3%, RR 3.60). This also translated to significantly lower surgical rates with use of a brace (4.8%), as compared to the use of backslab (30.8%, RR 6.22). Surgical rates were not lowered significantly when compared against the use of a cylindrical cast. During the assessment at 6 weeks postinjury, all patients were assessed for presence of pain, any limitation of range-of-motion, and weight-bearing status. Those treated with a backslab were significantly more likely to be still in pain (RR 3.24). There was no statistical difference between range-of-motion or weight-bearing status between the three groups. Discussion Despite all the recent advances in the understanding of patellofemoral pathology, there remains until date, a lack of high-level research data that help us answer two simple questions: (1) is immobilization necessary; and (2) if so, which form of immobilization is superior? Immobilization or early mobilization Traditional teaching has been to manage first-time patella dislocators in a cylinder cast for 6 weeks duration.11 This period of immobilization allows the soft tissues (including the medial retinaculum) to heal, repair, and fibrose. Advocators of early mobilization believe that a period of immobilization would result in muscle atrophy, with secondary effects on joint proprioception, pain sensation and joint contractures. Two recent meta-analyses in 20108 and 20129 could not give us conclusive answers due to a paucity of literature. After thorough literature searches, Smith identified only two studies that met their inclusion criteria,6,12 and van Gemert et al9 found an article by Maenpaa and Lehto6 (1997) to be the only study that met theirs. Smith's conclusion in his review article was that there was insufficient evidence in size and quality to justify the use of immobilization following a lateral patellar dislocation. The group from Northampton has attempted to address this question with a pilot feasibility study.13 Although they showed a trend towards superior short-term functional outcomes for those not immobilized, their study, unfortunately, recruited only eight study participants, and was unable to provide statistical evaluation. Sillanpaa14 in Arthroscopy 2011 compared immobilization against free range-of-motion in a knee brace prospectively. They found that early mobilization with the help of a knee brace did not increase recurrent dislocations, and instead, improved the return of range-of-motion. Without higher-level evidence emerging, our opinion is that first-time patella dislocators should still be managed with initial controlled immobilization. Which form of immobilization Several immobilization techniques exist. These range from cylinder casts, to posterior splints (backslab), knee braces, to patella taping. The ideal immobilization technique has not been identified. An article by Maenpaa and Lehto6 showed that the posterior splint
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K.Y. Lam et al. / Journal of Orthopaedics, Trauma and Rehabilitation 23 (2017) 30e33
Table 1 Demographics and radiographic measurements of participants
Number of patients Number of knees Age at diagnosis (y) Minimum Maximum Mean Gender Male Female Side Right Left Race (2013 statistics10) Chinese (74.2%) Malay (13.3%) Indian (9.1%) Others (3.3%) Radiographic measurements Insall-Salvati ratio (mean) Sulcus Angle (mean) Patella Tilt angle (mean)
Brace
Backslab
Cast
Total
101 (71.1%) 105 (71.4%)
13 (9.2%) 13 (8.8%)
28 (19.7%) 29 (19.7%)
142 147
p
8.08 17.33 13.96
11.25 16.25 13.6
8.58 15.5 13.47
8.08 17.33 13.83
0.31
46 55
4 9
12 16
62 (43.7%) 80 (56.3%)
0.6
50 55
4 9
12 17
66 (45.1%) 81 (54.9%)
0.47
58 13 25 5
6 3 4 0
18 3 5 2
82 (57.7%) 19 (13.4%) 34 (23.9%) 7 (4.9%)
0.78
1.42 139.8 17.4
1.48 137.5 14
1.43 144.2 18
1.43 140.2 17.2
0.68 0.26 0.21
Table 2 Comparison of treatment outcomes Brace
Backslab
Cast
Total
p
Redislocation No Yes (Relative risk with 95% CI)
96 (91.4%) 9 (8.6%) 1.00
7 (53.8%) 6 (46.2%) 5.18 (2.20e12.20)
20 (69.0%) 9 (31.0%) 3.60 (1.58e8.22)
123 (83.7%) 24 (16.3%)
0.00
Surgery No Yes (Relative risk with 95% CI)
100 (95.2%) 5 (4.8%) 1.00
9 (69.2%) 4 (30.8%) 6.22 (1.91e20.25)
27 (93.1%) 2 (6.9%) 1.44 (0.30e7.04)
136 (92.5%) 11 (7.5%)
0.00
Range-of-motion Full Limited (Relative risk with 95% CI)
95 (90.5%) 10 (9.5%) 1.00
10 (76.9%) 3 (23.1%) 2.33 (0.74e7.39)
27 (93.1%) 2 (6.9%) 0.72 (0.17e3.10)
132 (89.8%) 15 (10.2%)
0.25
Pain No Yes (Relative risk with 95% CI)
93 (88.6%) 12 (11.4%) 1.00
8 (61.5%) 5 (38.5%) 3.24 (1.36e7.72)
25 (86.2%) 4 (13.8%) 1.20 (0.42e3.44)
126 (85.7%) 21 (14.3%)
0.03
Weight bearing status Full Partial Non
97 (92.4%) 3 (2.9%) 5 (4.8%)
10 (76.9%) 2 (15.4%) 1 (7.7%)
26 (89.7%) 1 (3.4%) 2 (6.9%)
133 (90.5%) 6 (4.1%) 8 (5.4%)
0.28
may be superior to a cylinder cast and brace. However, critique of this study by van Gemert et al9 was that “the evidence remains low because of the small study population, difference in immobilization duration between groups, use of old braces, and limitations in the study design.” Smith et al8 in their review paper also stated that “there does not appear to be a statistically significant difference in respect to recurrent dislocation rates between immobilizing patients in a cylinder cast, posterior splint, or an elastic bandage”. Rood et al7compared the use of patella taping with cylindrical casting in patients above the age of 18 years, and found significantly better Lysholm scores at 6 weeks, 12 weeks, and 5 years postdislocation. In summary, the evidence supporting the various forms of immobilization is still conflicting. In addition, the majority of these studies were in a mixed (but predominantly adult) population. The
current available literature is unable to address the questions that we have on FTPDs in the paediatric age group. Our study shows that the use of a knee brace with a controlled immobilization protocol allows lower redislocation and surgical rates, and also avoids the problems of limited range-of-motion and persistent pain. Redislocation rate in our brace group was 8.6%. This is lower than the 10e44% often quoted for FTPDs. We believe that keeping our patients in a knee brace allows controlled increase in the range-of-motion. This prevents repeat dislocations due to uncontrolled knee joint motion, and still allows controlled early mobilization. A major drawback of this study is its retrospective nature. As with all retrospective studies, the quality of data collected is not ideal. At the 6 week assessment, we could not quantify the degree of rangeof-motion, or the degree of pain experienced. There were also no functional scores available for assessment. The duration of
K.Y. Lam et al. / Journal of Orthopaedics, Trauma and Rehabilitation 23 (2017) 30e33
immobilization also varied between the groups. For the cast and backslab group, the total immobilization period was for 4 weeks. We believe that any longer periods of casting or backslab immobilization would result in significant stiffness, which would be detrimental during the rehabilitation process. Using the brace, we could allow progressive range-of-motion, and this allowed us to use the brace for a duration of 6 week, without fear of excessive knee stiffness. Another criticism of this study is the large proportion of patients who were treated in brace. This observation is due to the fact that our department has been almost exclusively using the brace protocol in recent years. The decision behind this is that we had noted significant benefits from our earlier experience, as compared to the other immobilisation methods. The relatively smaller number of patients in the comparison groups resulted in wide confidence intervals during statistical analysis. Despite this, the benefit of the brace did reach statistical significance for lowered redislocation rates when compared to the backslab and cast groups, and for lowered surgical rates when compared to the backslab group. A prospective study may help to identify the ideal immobilization method in FTPDs more definitively. Conclusion Despite the drawbacks, our study is unique in that it compares the outcomes of various forms of nonoperative treatment of FTPDs in a paediatric population. We think this is relevant, as most incidences of FTPDs occur in this age group. We recommend the use of a knee brace, with a controlled immobilization protocol, for the nonoperative treatment of FTPDs in the paediatric age group. Conflicts of interest The authors have no conflicts of interest to declare. Funding/support No funding/financial support is received for this study.
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Acknowledgements The authors acknowledge the help of senior physiotherapist Ms. Ng Shin Huey during the data collection process.
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