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Notchplasty for the Arthroscopic Treatment of Limited Knee Extension
Notchplasty for the Arthroscopic Treatment of Limited Knee Extension Marcio B. Ferrari, M.D., Sandeep Mannava, M.D., Ph.D., Nicholas DePhillipo, M.S., A.T.C., George Sanchez, B.S., and Robert F. LaPrade, M.D., Ph.D.
Abstract: Knee osteoarthritis may lead to narrowing of the intercondylar notch due to osteophyte formation, thereby causing changes in native knee biomechanics. The normal close contact between the condyles and the anterior cruciate ligament (ACL) during knee extension may be compromised due to narrowing of the notch and result in ACL damage, progression of knee osteoarthritis, and loss of knee extension. Outcomes after a notchplasty procedure are well reported for ACL reconstruction in young patients. However, there remains a lack of studies evaluating this procedure in the setting of knee osteoarthritis in patients with a symptomatic loss of knee extension. The purpose of this Technical Note is to present our preferred surgical technique for the treatment of loss of knee extension in the setting of knee osteoarthritis in conjunction with osteophyte formation in the intercondylar notch.
T
he anterior cruciate ligament (ACL) and the intercondylar notch area are in close contact when the knee is in full extension. Congruency and space between the ACL and intercondylar area is necessary to maintain knee range of motion during extension and prevent damage to intra-articular structures. Osteophyte formation of the femoral notch can lead to ACL damage, loss of knee extension, and gait alteration.1
From the The Steadman Clinic (S.M., N.D.P., R.F.L.); and Steadman Philippon Research Institute (M.B.F., S.M., G.S., R.F.L.), Vail, Colorado, U.S.A. The authors report the following potential conflicts of interest or sources of funding: S.M. receives support from an American Board of Medical Specialties (ABMS)-American Board of Orthopaedic Surgeons (ABOS) Visiting Scholars Grant and a patent issued to Mannava S et al., Wake Forest University Health Sciences, Patent No. 08926626 awarded January 6, 2015, by the United States Patent and Trademark Office. R.F.L. receives support from Smith & Nephew Endoscopy, Ossur Americas, Arthrex, Siemens Medical Solutions USA, Small Bone Innovations, ConMed Linvatec, and Opedix. He is on the editorial/governing board for American Journal of Sports Medicine and Knee Surgery, Sports Traumatology, Arthroscopy, and has member/ committee appointments with American Orthopaedic Society for Sports Medicine; International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine; Arthroscopy Association of North America; and The European Society of Sports Traumatology, Knee Surgery and Arthroscopy. Received October 25, 2016; accepted November 28, 2016. Address correspondence to Robert F. LaPrade, M.D., Ph.D., Steadman Philippon Research Institute, The Steadman Clinic, 181 West Meadow Drive, Suite 400, Vail, CO 81657, U.S.A. E-mail: [email protected] Ó 2017 by the Arthroscopy Association of North America 2212-6287/161041/$36.00 http://dx.doi.org/10.1016/j.eats.2016.11.008
In the setting of an ACL reconstruction, a notchplasty may be performed to aid in surgical visualization and to treat limited knee extension in patients with a chronic ACL tear. A notchplasty procedure ultimately impacts ACL graft force, excursion, and pretensioning.2 Other pathologies, including malunited intercondylar eminence fractures of the tibia3 and mucoid hypertrophy of the ACL, can be treated with notchplasty.4,5 This procedure can be complicated by over-resection and articular cartilage damage; thus attention to detail is paramount when performing the procedure.6 The objective of this Technical Note is to describe our arthroscopic surgical technique to address narrowing of the intercondylar notch, or notchplasty, to improve knee range of motion during extension.
Examination Under Anesthesia After induction of general anesthesia and before operative positioning, a standard examination under anesthesia is performed with the patient supine on the operating table (Video 1). Examination of knee range of motion is first performed with extension and flexion of the knee and objectively measured via the use of a goniometer. Patients with osteophytes of the femoral intercondylar notch will typically have reduced knee extension caused by impingement of the notch onto the ACL. It should be noted that comparison with the contralateral or nonoperative extremity is essential to determine their normal knee extension or hyperextension. In our case example, the patient had terminal extension to 15 and full flexion to 138 in the
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Fig 1. Arthroscopic (A and B) and magnetic resonance images (MRI) (C and D) of the impingement of the osteophyte at the intercondylar notch against the anterior cruciate ligament (ACL) in a left knee. The impingement area (blue arrows) can be arthroscopically visualized as a localized damage on the ACL with the knee in flexion (A and B), which can also be preoperatively evaluated (red arrows) using the coronal (C) and sagittal (D) MRI views in T1.
operative knee, whereas the contralateral knee had terminal extension to 5 and full flexion to 139 . Further examination of the affected knee under anesthesia should verify any abnormalities of the skin, including swelling and effusion. Ligamentous stability is evaluated during routine physical examination. Examination through varus and valgus stress at both 0 and 30 of knee flexion is also performed. In addition, dial testing at 30 and 90 is performed as well as the pivot shift and reverse pivot shift tests.
Diagnostic Knee Arthroscopy After examination under anesthesia, a leg holder is used over a proximally placed thigh tourniquet, ensuring adequate room for surgical intervention. The contralateral, nonoperative leg is placed in a leg holder. The patient is then prepared and draped in a standard fashion. The leg is exsanguinated and the thigh tourniquet is inflated. A standard anterolateral arthroscopic portal is made close to the patellar tendon in the region
of the lateral knee joint line. A medial portal is then made under arthroscopic visualization in a standard fashion in close proximity to the patellar tendon. The portals should be of adequate size to facilitate insertion of arthroscopic instruments and to aid in osteophyte removal. A routine diagnostic arthroscopy is performed. It is important that a standardized and systematic approach is taken when evaluating the knee joint arthroscopically. In the case example, there was obvious overgrowth of the femoral intercondylar notch with exuberant osteophyte formation. During dynamic arthroscopic assessment of the joint, impingement of the ACL on the femoral intercondylar notch is visualized during knee extension and the impingement of the osteophyte can produce a localized deformity in the ACL visualized with the knee in flexion (Fig 1). The osteophyte typically appears whiter in color than “normal” cartilage, and there is usually a defined interface between the abnormal osteophyte and the normal cartilage surface.
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Resection of the Femoral Intercondylar Notch Osteophyte
Fig 2. Arthroscopic resection of an osteophyte in the lateral condyle performed in a left knee intercondylar notch. The impingement area with the anterior cruciate ligament is arthroscopically evaluated during flexion and extension of the knee. The resection of the osteophytes can be performed using an osteotome. Usually, an interface between the normal and the pathologic bone formation can be visualized with a tendency for a “softer” and “whiter” appearance of the fibrocartilage surface on the osteophyte. (LFC, lateral femoral condyle.)
The arthroscopic camera is placed in the anteromedial portal and instruments are placed through the anterolateral-working portal. An osteotome is placed through the working portal and gentle malletting is used to resect exuberant portions of the osteophyte (Fig 2). The resection is performed under visualization and an attempt is made to keep the resected osteophyte rather large to facilitate both grasping and retrieval from the joint (Fig 3). The osteotome should be placed on the normal-abnormal interface of the healthy bone and osteophyte before resection. The osteotome should be repositioned after initial resection and gently worked circumferentially around the notch. After some of the osteophytes are broken free, the osteotome should be removed and an arthroscopic grasper or a small Kocher clamp can be used to remove the fragmented osteophyte. The viewing and working portal may be changed to facilitate a more advantageous angle for osteotome resection. The resection should be performed gradually and systematically.
Fig 3. Notchplasty performed in a left knee. The intercondylar notch space is evaluated for the presence of osteophytes using a 30 arthroscope through the anteromedial portal. The lateral femoral condyle is evaluated. The interface between the normal and pathologic bone is identified and an osteotome is positioned here through an anterolateral portal (A). The resection is performed by gently malletting the osteotome to resect portions of the osteophyte (B and C). An attempt is made to keep the resected osteophyte large to facilitate grasping and retrieval from the joint (D). (MFC, medial femoral condyle.)
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resecting/cutting shavers, including the 4.5-mm full radius bone cutter (Smith & Nephew), can also be used on burr mode for measured resection of the osteophyte within the notch (Fig 5). In addition, most patients who require this procedure have an anterior tibial “anvil” osteophyte (Fig 6). Careful resection of the anvil osteophyte is performed, taking care to avoid the anterior meniscal root and ACL attachments.
Examination Under Anesthesia After Completion of Notchplasty
Fig 4. After the osteophyte is resected using an osteotome, a burr can be used to resect any pathologic tissue in this left knee. The burr can be used on reverse to ensure a more controlled and less aggressive resection. The burr is used to both resect and shape the femoral intercondylar notch.
After large fragments of the osteophyte are removed using the osteotome, a 4.5-mm full radius shaver (Smith & Nephew, Andover, MA) is used to clear soft tissue and scar tissue from the notch. The judicious use of suction will facilitate removal of this abnormal tissue and promote visualization. The shaver will help define the femoral intercondylar notch anatomy of the ACL. The notchplasty is further refined with a 5.5-mm round arthroscopic burr (Smith & Nephew) (Fig 4). Care is taken not to disrupt the ACL or posterior cruciate ligament with the burr. Furthermore, care is taken to avoid injury to the femoral cartilage surface. Using the burr on reverse helps to ensure a controlled and less aggressive resection and removes frayed tissue at the edge of the notchplasty to facilitate visualization during resection. After adequate resection and shaping of the notch using the burr, the arthroscopic shaver is once again introduced into the notch to clear remaining debris and aid in visualization. Some arthroscopic bone
After adequate resection, arthroscopic examination with visualization of the completed notchplasty is performed during knee range of motion (Fig 7). Adequate resection is confirmed if knee extension can be performed without impingement of the notch on the ACL. A burr can be used to perform an enlargement of the notch, placing it in the most anterior part of the condyle and carefully moving the burr to the posterior aspect (Fig 8). Furthermore, confirmation of terminal extension of the knee with a sterile goniometer should also show improved extension (Fig 9). In our case example, the patient improved from a preoperative 15 contracture at terminal extension to 2 of hyperextension postoperatively. Table 1 summarizes the pearls and pitfalls, whereas Table 2 summarizes advantages and disadvantages of our surgical technique.
Rehabilitation After surgery, the patient is weightbearing as tolerated with the aid of crutches for approximately 1 week. A knee immobilizer is occasionally prescribed if regional anesthesia or peripheral nerve blockade is used for perioperative pain control until adequate quadriceps function is regained. Active and passive range of motion exercises are initiated on postoperative day 1 without restriction. Patients progress to full range of motion as tolerated, with an emphasis on knee extension. If the notchplasty is performed in conjunction with a manipulation under anesthesia, a dynamic knee
Fig 5. To perform a notchplasty procedure in this left knee, a combination of burr, shaver, and osteotome is used. The osteotome and the burr are the first to be used, ensuring the gross resection of the osteophytes. A shaver is then used to remove any debris and to complete the resection. Using the sleeve of the shaver in contact with the anterior cruciate ligament (ACL), the osteophytes surrounding the ACL are carefully resected (A and B). The final view of the notch after resection can be visualized with the knee in flexion (C) and extension. (LFC, lateral femoral condyle; MFC, medial femoral condyle.)
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Fig 6. Magnetic resonance image performed in a left knee, preoperatively. The sagittal view in T1 is used to evaluate the osteophytes. The anterior tibial osteophyte (red arrow), also known as an “anvil osteophyte,” is often related to this pathology and can lead to impingement against the femur and cause knee flexion deformity. Of note, care must be taken while performing the resection of this osteophyte to avoid iatrogenic lesions to the anterior meniscal root attachment and the anterior cruciate ligament insertion.
extension splint is prescribed for daily use throughout the first 12 weeks of rehabilitation, typically 6 to 8 hours a day. Otherwise, no postoperative bracing is used after notchplasty performed in isolation during knee arthroscopy. During the first 6 weeks, the patient’s primary exercises are patellar mobilizations, active and passive knee range of motion exercises, and quadriceps activation exercises. Patients are allowed to spin on a stationary bike with no resistance during the
first week of rehabilitation. Balance and proprioception exercises are initiated at postoperative week 4. At 7 weeks, patients are permitted to swim (with fins) and perform treadmill walking with a maximum 7% incline. After full knee extension is attained and maintained, as well as the re-establishment of adequate quadriceps control, closed chain strengthening exercises are initiated with training periodization focusing first on developing muscular endurance, followed by strength and power. Weightbearing strengthening exercises are initiated after 8 weeks, with leg press allowed at postoperative week 10. Patients may begin running exercises at 3 months, with initiation of speed and agility drills at 4 months. In our practice, gradual return to play progression is initiated after 4 months following the successful completion of a functional sports test. Return to sports or activity is allowed when normal strength, stability, and knee range of motion comparable with the contralateral side have been achieved; this typically occurs at 4-5 months postoperatively.
Discussion This Technical Note describes our preferred arthroscopic surgical technique to address patients with a symptomatic loss of knee extension due to femoral intercondylar notch narrowing. The femoral notch morphology undergoes natural age-related changes with narrowing at the distal portion and widening at the proximal portion.7 Moreover, differences in notch volume due to gender have been reported, with females showing less notch volume.8 For the evaluation of stenosis, radiographs and computed tomography can be used to measure the notch width index.9 More recently, magnetic resonance imaging has been used as an accurate imaging modality for measurement of the notch width.10 An additional
Fig 7. Arthroscopic evaluation of the anterior cruciate ligament and the intercondylar notch in a left knee using a 30 arthroscope through the anterolateral portal. Once the anterior cruciate ligament (ACL) is carefully released from the osteophytes, dynamic evaluation of the impingement is performed through knee flexion (A) and extension (B). (LFC, lateral femoral condyle; MFC, medial femoral condyle.)
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Fig 8. To excise the osteophyte coming into close contact with the femoral cartilage, a burr is used on reverse to ensure a controlled resection in a left knee. The burr is positioned at the most anterior aspect of the cartilage (A). Then, using smooth movements in an anteroposterior direction, the resection is performed as the size and depth of the notch are extended (B). (MFC, medial femoral condyle.)
Fig 9. Physical examination performed in a left knee under general anesthesia. The deficit in knee extension is evaluated before (A) and after (B) surgery using a goniometer to ensure that the loss in extension is biomechanical and not due to pain. This will help verify that all osteophytes leading to loss of extension were excised and that normal knee extension has been re-established. Of note, the contralateral limb can be used as a reference if not affected.
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NOTCHPLASTY FOR LIMITED KNEE EXTENSION Table 1. Pearls and Pitfalls of the Notchplasty Technique Pearls The osteophyte typically appears whiter than the “normal” cartilage.
There is usually a defined interface between the abnormal osteophyte and the normal articular cartilage that is readily visualized arthroscopically. The combination of a burr, shaver, and osteotome makes the resection easier.
Pitfalls Damage to the cartilage and to the anterior and posterior cruciate ligaments can occur if judicious and controlled resection is not performed. Portals that are too far away from the patella tendon decrease visualization and instrumentation within the intercondylar notch. Damage to the anterior meniscal root and ACL attachment can occur if the resection of the “anvil” osteophyte is not carefully performed.
An arthroscopic evaluation of the impingement should be performed through dynamic extension of the knee. This will be the guide for the resection. Using the burr on reverse allows more precision and decreases the risk of cartilage damage due to aggressive resection.
benefit of magnetic resonance imaging is that it allows for assessment of other aspects of the knee joint, including the integrity of the ACL. Osteophyte formation can result in decreased intercondylar notch volume, which impacts and impinges on the ACL during the extremes of knee extension that could result in ACL injury. This impingement may progress to ACL degeneration and may alter knee biomechanics and proprioception.1,11 However, although the notchplasty procedure and its relation to ACL reconstruction are well Table 2. Advantages and Disadvantages of the Notchplasty Technique Advantages
Disadvantages
This technique improves knee motion in extension and resolves pain due to abnormal gait mechanics. A dynamic evaluation of the impingement ensures the complete resection of the osteophytes. This technique can avoid or delay impingement on the anterior cruciate ligament. Concomitant pathologies can be treated arthroscopically while completing the notchplasty.
Iatrogenic damage to the cartilage and ligaments can occur during resection. Recurrence of the osteophytes and loss of extension may be seen in some patients.
described,2,6,12-17 the effects of notchplasty in the setting of osteoarthritis remain unclear. Leon et al.1 described 4 types of intercondylar stenosis in knees associated with degenerative osteoarthritis based on anatomic findings. These 4 types of intercondylar stenosis included type I, anterior with osteophyte formation leading to damage of the anterodistal part of the ACL; type II, osteophyte formation resulting in damage at the midlateral area; type III, a combination of types I and II, both anterior and midlateral portion damage, which has been shown to be the most prevalent; and type IV, stenosis resulting from a previous massive, complex injury. In all cases, regardless of type, the authors found evidence of knee instability and decreased muscular strength, with 61% presenting with associated loss of knee extension. The notchplasty procedure was successfully performed, restoring knee biomechanics and range of motion. Puddu et al.18 also reported improvement in active extension and a decrease in pain and stiffness of the knee after the removal of the anterior tibial osteophyte and a notchplasty procedure. Moreover, a survey performed with 170 orthopaedic surgeons with more than 10 years of experience and more than 100 arthroscopies performed per year reported that the most interviewees consider notchplasty as a reasonable procedure to address extension deficits associated with intercondylar stenosis, with 14.7% reporting very good and 5.3% reporting excellent results.19 However, Lakdawala et al.,20 the authors that introduced the term “anvil osteophyte,” raised doubts if this tibial bone formation is mainly responsible for the knee flexion deformity and if its resection alone improves outcomes. In summary, the described arthroscopic femoral notchplasty technique allows for restoration of the notch volume, ultimately improving ACL-notch impingement and re-establishing space for the ACL during knee extension. Care during this surgical technique must be taken to avoid iatrogenic damage to the articular cartilage and ligaments in close proximity of this osteoplasty of the femoral intercondylar notch, as well as the anterior meniscal root and ACL attachment during the tibial osteophyte resection. Notchplasty may help to restore knee extension, thereby, improving knee biomechanics and gait. Nevertheless, the outcomes of this procedure related to ACL integrity, restoration of muscular strength, and the length of symptomatic relief urge further study. Therefore, longterm studies with large sample sizes are needed to further assess the efficacy of this procedure.
References 1. Leon HO, Blanco CE, Guthrie TB, Martinez OJ. Intercondylar notch stenosis in degenerative arthritis of the knee. Arthroscopy 2005;21:294-302. 2. Markolf KL, Hame SL, Hunter DM, Oakes D, Gause P. Biomechanical effects of femoral notchplasty in anterior
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cruciate ligament reconstruction. Am J Sports Med 2002;30: 83-89. Luger EJ, Arbel R, Eichenblat MS, Menachem A, Dekel S. Femoral notchplasty in the treatment of malunited intercondylar eminence fractures of the tibia. Arthroscopy 1994;10:550-551. Kim TH, Lee DH, Lee SH, Kim JM, Kim CW, Bin SI. Arthroscopic treatment of mucoid hypertrophy of the anterior cruciate ligament. Arthroscopy 2008;24:642-649. Chudasama CH, Chudasama VC, Prabhakar MM. Arthroscopic management of mucoid degeneration of anterior cruciate ligament. Indian J Orthop 2012;46: 561-565. LaPrade RF, Terry GC, Montgomery RD, Curd D, Simmons DJ. Winner of the AlbertTrillat Young Investigator Award. The effects of aggressive notchplasty on the normal knee in dogs. Am J Sports Med 1998;26:193-200. Hirtler L, Rohrich S, Kainberger F. The femoral intercondylar notch during life: An anatomic redefinition with patterns predisposing to cruciate ligament impingement. AJR Am J Roentgenol 2016;207:836-845. Charlton WP, St John TA, Ciccotti MG, Harrison N, Schweitzer M. Differences in femoral notch anatomy between men and women: A magnetic resonance imaging study. Am J Sports Med 2002;30:329-333. Souryal TO, Moore HA, Evans JP. Bilaterality in anterior cruciate ligament injuries: Associated intercondylar notch stenosis. Am J Sports Med 1988;16:449-454. Chen C, Ma Y, Geng B, et al. Intercondylar notch stenosis of knee osteoarthritis and relationship between stenosis and osteoarthritis complicated with anterior cruciate ligament injury: A study in MRI. Medicine (Baltimore) 2016;95:e3439.
11. Wada M, Tatsuo H, Baba H, Asamoto K, Nojyo Y. Femoral intercondylar notch measurements in osteoarthritic knees. Rheumatology (Oxford) 1999;38:554-558. 12. Hame SL, Markolf KL, Hunter DM, Oakes DA, Zoric B. Effects of notchplasty and femoral tunnel position on excursion patterns of an anterior cruciate ligament graft. Arthroscopy 2003;19:340-345. 13. Zuiderbaan HA, Khamaisy S, Nawabi DH, et al. Notchplasty in anterior cruciate ligament reconstruction in the setting of passive anterior tibial subluxation. Knee 2014;21:1160-1165. 14. Koga H, Muneta T, Yagishita K, et al. Effect of notchplasty in anatomic double-bundle anterior cruciate ligament reconstruction. Am J Sports Med 2014;42: 1813-1821. 15. Kanamiya T, Hara M, Naito M. Magnetic resonance imaging evaluation after re-notchplasty at second-look arthroscopy. Arthroscopy 2002;18:584-588. 16. Bents RT, Jones RC, May DA, Snearly WS. Intercondylar notch encroachment following anterior cruciate ligament reconstruction: A prospective study. Am J Knee Surg 1998;11:81-88. 17. Iriuchishima T, Shirakura K, Fu FH. Graft impingement in anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc 2013;21:664-670. 18. Puddu G, Cipolla M, Cerullo G, Scala A. Arthroscopic treatment of the flexed arthritic knee in active middleaged patients. Knee Surg Sports Traumatol Arthrosc 1994;2: 73-75. 19. Mayr HO, Rueschenschmidt M, Seil R, et al. Indications for and results of arthroscopy in the arthritic knee: A European survey. Int Orthop 2013;37:1263-1271. 20. Lakdawala A, Ireland J. The ‘anvil’ osteophyteda primary cause of fixed flexion of the knee? Knee 2005;12:191-193.
Abstract: Knee osteoarthritis may lead to narrowing of the intercondylar notch due to osteophyte formation, thereby causing changes in native knee biomechanics. The normal close contact between the condyles and the anterior cruciate ligament (ACL) during knee extension may be compromised due to narrowing of the notch and result in ACL damage, progression of knee osteoarthritis, and loss of knee extension. Outcomes after a notchplasty procedure are well reported for ACL reconstruction in young patients. However, there remains a lack of studies evaluating this procedure in the setting of knee osteoarthritis in patients with a symptomatic loss of knee extension. The purpose of this Technical Note is to present our preferred surgical technique for the treatment of loss of knee extension in the setting of knee osteoarthritis in conjunction with osteophyte formation in the intercondylar notch.
T
he anterior cruciate ligament (ACL) and the intercondylar notch area are in close contact when the knee is in full extension. Congruency and space between the ACL and intercondylar area is necessary to maintain knee range of motion during extension and prevent damage to intra-articular structures. Osteophyte formation of the femoral notch can lead to ACL damage, loss of knee extension, and gait alteration.1
From the The Steadman Clinic (S.M., N.D.P., R.F.L.); and Steadman Philippon Research Institute (M.B.F., S.M., G.S., R.F.L.), Vail, Colorado, U.S.A. The authors report the following potential conflicts of interest or sources of funding: S.M. receives support from an American Board of Medical Specialties (ABMS)-American Board of Orthopaedic Surgeons (ABOS) Visiting Scholars Grant and a patent issued to Mannava S et al., Wake Forest University Health Sciences, Patent No. 08926626 awarded January 6, 2015, by the United States Patent and Trademark Office. R.F.L. receives support from Smith & Nephew Endoscopy, Ossur Americas, Arthrex, Siemens Medical Solutions USA, Small Bone Innovations, ConMed Linvatec, and Opedix. He is on the editorial/governing board for American Journal of Sports Medicine and Knee Surgery, Sports Traumatology, Arthroscopy, and has member/ committee appointments with American Orthopaedic Society for Sports Medicine; International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine; Arthroscopy Association of North America; and The European Society of Sports Traumatology, Knee Surgery and Arthroscopy. Received October 25, 2016; accepted November 28, 2016. Address correspondence to Robert F. LaPrade, M.D., Ph.D., Steadman Philippon Research Institute, The Steadman Clinic, 181 West Meadow Drive, Suite 400, Vail, CO 81657, U.S.A. E-mail: [email protected] Ó 2017 by the Arthroscopy Association of North America 2212-6287/161041/$36.00 http://dx.doi.org/10.1016/j.eats.2016.11.008
In the setting of an ACL reconstruction, a notchplasty may be performed to aid in surgical visualization and to treat limited knee extension in patients with a chronic ACL tear. A notchplasty procedure ultimately impacts ACL graft force, excursion, and pretensioning.2 Other pathologies, including malunited intercondylar eminence fractures of the tibia3 and mucoid hypertrophy of the ACL, can be treated with notchplasty.4,5 This procedure can be complicated by over-resection and articular cartilage damage; thus attention to detail is paramount when performing the procedure.6 The objective of this Technical Note is to describe our arthroscopic surgical technique to address narrowing of the intercondylar notch, or notchplasty, to improve knee range of motion during extension.
Examination Under Anesthesia After induction of general anesthesia and before operative positioning, a standard examination under anesthesia is performed with the patient supine on the operating table (Video 1). Examination of knee range of motion is first performed with extension and flexion of the knee and objectively measured via the use of a goniometer. Patients with osteophytes of the femoral intercondylar notch will typically have reduced knee extension caused by impingement of the notch onto the ACL. It should be noted that comparison with the contralateral or nonoperative extremity is essential to determine their normal knee extension or hyperextension. In our case example, the patient had terminal extension to 15 and full flexion to 138 in the
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Fig 1. Arthroscopic (A and B) and magnetic resonance images (MRI) (C and D) of the impingement of the osteophyte at the intercondylar notch against the anterior cruciate ligament (ACL) in a left knee. The impingement area (blue arrows) can be arthroscopically visualized as a localized damage on the ACL with the knee in flexion (A and B), which can also be preoperatively evaluated (red arrows) using the coronal (C) and sagittal (D) MRI views in T1.
operative knee, whereas the contralateral knee had terminal extension to 5 and full flexion to 139 . Further examination of the affected knee under anesthesia should verify any abnormalities of the skin, including swelling and effusion. Ligamentous stability is evaluated during routine physical examination. Examination through varus and valgus stress at both 0 and 30 of knee flexion is also performed. In addition, dial testing at 30 and 90 is performed as well as the pivot shift and reverse pivot shift tests.
Diagnostic Knee Arthroscopy After examination under anesthesia, a leg holder is used over a proximally placed thigh tourniquet, ensuring adequate room for surgical intervention. The contralateral, nonoperative leg is placed in a leg holder. The patient is then prepared and draped in a standard fashion. The leg is exsanguinated and the thigh tourniquet is inflated. A standard anterolateral arthroscopic portal is made close to the patellar tendon in the region
of the lateral knee joint line. A medial portal is then made under arthroscopic visualization in a standard fashion in close proximity to the patellar tendon. The portals should be of adequate size to facilitate insertion of arthroscopic instruments and to aid in osteophyte removal. A routine diagnostic arthroscopy is performed. It is important that a standardized and systematic approach is taken when evaluating the knee joint arthroscopically. In the case example, there was obvious overgrowth of the femoral intercondylar notch with exuberant osteophyte formation. During dynamic arthroscopic assessment of the joint, impingement of the ACL on the femoral intercondylar notch is visualized during knee extension and the impingement of the osteophyte can produce a localized deformity in the ACL visualized with the knee in flexion (Fig 1). The osteophyte typically appears whiter in color than “normal” cartilage, and there is usually a defined interface between the abnormal osteophyte and the normal cartilage surface.
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Resection of the Femoral Intercondylar Notch Osteophyte
Fig 2. Arthroscopic resection of an osteophyte in the lateral condyle performed in a left knee intercondylar notch. The impingement area with the anterior cruciate ligament is arthroscopically evaluated during flexion and extension of the knee. The resection of the osteophytes can be performed using an osteotome. Usually, an interface between the normal and the pathologic bone formation can be visualized with a tendency for a “softer” and “whiter” appearance of the fibrocartilage surface on the osteophyte. (LFC, lateral femoral condyle.)
The arthroscopic camera is placed in the anteromedial portal and instruments are placed through the anterolateral-working portal. An osteotome is placed through the working portal and gentle malletting is used to resect exuberant portions of the osteophyte (Fig 2). The resection is performed under visualization and an attempt is made to keep the resected osteophyte rather large to facilitate both grasping and retrieval from the joint (Fig 3). The osteotome should be placed on the normal-abnormal interface of the healthy bone and osteophyte before resection. The osteotome should be repositioned after initial resection and gently worked circumferentially around the notch. After some of the osteophytes are broken free, the osteotome should be removed and an arthroscopic grasper or a small Kocher clamp can be used to remove the fragmented osteophyte. The viewing and working portal may be changed to facilitate a more advantageous angle for osteotome resection. The resection should be performed gradually and systematically.
Fig 3. Notchplasty performed in a left knee. The intercondylar notch space is evaluated for the presence of osteophytes using a 30 arthroscope through the anteromedial portal. The lateral femoral condyle is evaluated. The interface between the normal and pathologic bone is identified and an osteotome is positioned here through an anterolateral portal (A). The resection is performed by gently malletting the osteotome to resect portions of the osteophyte (B and C). An attempt is made to keep the resected osteophyte large to facilitate grasping and retrieval from the joint (D). (MFC, medial femoral condyle.)
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resecting/cutting shavers, including the 4.5-mm full radius bone cutter (Smith & Nephew), can also be used on burr mode for measured resection of the osteophyte within the notch (Fig 5). In addition, most patients who require this procedure have an anterior tibial “anvil” osteophyte (Fig 6). Careful resection of the anvil osteophyte is performed, taking care to avoid the anterior meniscal root and ACL attachments.
Examination Under Anesthesia After Completion of Notchplasty
Fig 4. After the osteophyte is resected using an osteotome, a burr can be used to resect any pathologic tissue in this left knee. The burr can be used on reverse to ensure a more controlled and less aggressive resection. The burr is used to both resect and shape the femoral intercondylar notch.
After large fragments of the osteophyte are removed using the osteotome, a 4.5-mm full radius shaver (Smith & Nephew, Andover, MA) is used to clear soft tissue and scar tissue from the notch. The judicious use of suction will facilitate removal of this abnormal tissue and promote visualization. The shaver will help define the femoral intercondylar notch anatomy of the ACL. The notchplasty is further refined with a 5.5-mm round arthroscopic burr (Smith & Nephew) (Fig 4). Care is taken not to disrupt the ACL or posterior cruciate ligament with the burr. Furthermore, care is taken to avoid injury to the femoral cartilage surface. Using the burr on reverse helps to ensure a controlled and less aggressive resection and removes frayed tissue at the edge of the notchplasty to facilitate visualization during resection. After adequate resection and shaping of the notch using the burr, the arthroscopic shaver is once again introduced into the notch to clear remaining debris and aid in visualization. Some arthroscopic bone
After adequate resection, arthroscopic examination with visualization of the completed notchplasty is performed during knee range of motion (Fig 7). Adequate resection is confirmed if knee extension can be performed without impingement of the notch on the ACL. A burr can be used to perform an enlargement of the notch, placing it in the most anterior part of the condyle and carefully moving the burr to the posterior aspect (Fig 8). Furthermore, confirmation of terminal extension of the knee with a sterile goniometer should also show improved extension (Fig 9). In our case example, the patient improved from a preoperative 15 contracture at terminal extension to 2 of hyperextension postoperatively. Table 1 summarizes the pearls and pitfalls, whereas Table 2 summarizes advantages and disadvantages of our surgical technique.
Rehabilitation After surgery, the patient is weightbearing as tolerated with the aid of crutches for approximately 1 week. A knee immobilizer is occasionally prescribed if regional anesthesia or peripheral nerve blockade is used for perioperative pain control until adequate quadriceps function is regained. Active and passive range of motion exercises are initiated on postoperative day 1 without restriction. Patients progress to full range of motion as tolerated, with an emphasis on knee extension. If the notchplasty is performed in conjunction with a manipulation under anesthesia, a dynamic knee
Fig 5. To perform a notchplasty procedure in this left knee, a combination of burr, shaver, and osteotome is used. The osteotome and the burr are the first to be used, ensuring the gross resection of the osteophytes. A shaver is then used to remove any debris and to complete the resection. Using the sleeve of the shaver in contact with the anterior cruciate ligament (ACL), the osteophytes surrounding the ACL are carefully resected (A and B). The final view of the notch after resection can be visualized with the knee in flexion (C) and extension. (LFC, lateral femoral condyle; MFC, medial femoral condyle.)
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Fig 6. Magnetic resonance image performed in a left knee, preoperatively. The sagittal view in T1 is used to evaluate the osteophytes. The anterior tibial osteophyte (red arrow), also known as an “anvil osteophyte,” is often related to this pathology and can lead to impingement against the femur and cause knee flexion deformity. Of note, care must be taken while performing the resection of this osteophyte to avoid iatrogenic lesions to the anterior meniscal root attachment and the anterior cruciate ligament insertion.
extension splint is prescribed for daily use throughout the first 12 weeks of rehabilitation, typically 6 to 8 hours a day. Otherwise, no postoperative bracing is used after notchplasty performed in isolation during knee arthroscopy. During the first 6 weeks, the patient’s primary exercises are patellar mobilizations, active and passive knee range of motion exercises, and quadriceps activation exercises. Patients are allowed to spin on a stationary bike with no resistance during the
first week of rehabilitation. Balance and proprioception exercises are initiated at postoperative week 4. At 7 weeks, patients are permitted to swim (with fins) and perform treadmill walking with a maximum 7% incline. After full knee extension is attained and maintained, as well as the re-establishment of adequate quadriceps control, closed chain strengthening exercises are initiated with training periodization focusing first on developing muscular endurance, followed by strength and power. Weightbearing strengthening exercises are initiated after 8 weeks, with leg press allowed at postoperative week 10. Patients may begin running exercises at 3 months, with initiation of speed and agility drills at 4 months. In our practice, gradual return to play progression is initiated after 4 months following the successful completion of a functional sports test. Return to sports or activity is allowed when normal strength, stability, and knee range of motion comparable with the contralateral side have been achieved; this typically occurs at 4-5 months postoperatively.
Discussion This Technical Note describes our preferred arthroscopic surgical technique to address patients with a symptomatic loss of knee extension due to femoral intercondylar notch narrowing. The femoral notch morphology undergoes natural age-related changes with narrowing at the distal portion and widening at the proximal portion.7 Moreover, differences in notch volume due to gender have been reported, with females showing less notch volume.8 For the evaluation of stenosis, radiographs and computed tomography can be used to measure the notch width index.9 More recently, magnetic resonance imaging has been used as an accurate imaging modality for measurement of the notch width.10 An additional
Fig 7. Arthroscopic evaluation of the anterior cruciate ligament and the intercondylar notch in a left knee using a 30 arthroscope through the anterolateral portal. Once the anterior cruciate ligament (ACL) is carefully released from the osteophytes, dynamic evaluation of the impingement is performed through knee flexion (A) and extension (B). (LFC, lateral femoral condyle; MFC, medial femoral condyle.)
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Fig 8. To excise the osteophyte coming into close contact with the femoral cartilage, a burr is used on reverse to ensure a controlled resection in a left knee. The burr is positioned at the most anterior aspect of the cartilage (A). Then, using smooth movements in an anteroposterior direction, the resection is performed as the size and depth of the notch are extended (B). (MFC, medial femoral condyle.)
Fig 9. Physical examination performed in a left knee under general anesthesia. The deficit in knee extension is evaluated before (A) and after (B) surgery using a goniometer to ensure that the loss in extension is biomechanical and not due to pain. This will help verify that all osteophytes leading to loss of extension were excised and that normal knee extension has been re-established. Of note, the contralateral limb can be used as a reference if not affected.
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NOTCHPLASTY FOR LIMITED KNEE EXTENSION Table 1. Pearls and Pitfalls of the Notchplasty Technique Pearls The osteophyte typically appears whiter than the “normal” cartilage.
There is usually a defined interface between the abnormal osteophyte and the normal articular cartilage that is readily visualized arthroscopically. The combination of a burr, shaver, and osteotome makes the resection easier.
Pitfalls Damage to the cartilage and to the anterior and posterior cruciate ligaments can occur if judicious and controlled resection is not performed. Portals that are too far away from the patella tendon decrease visualization and instrumentation within the intercondylar notch. Damage to the anterior meniscal root and ACL attachment can occur if the resection of the “anvil” osteophyte is not carefully performed.
An arthroscopic evaluation of the impingement should be performed through dynamic extension of the knee. This will be the guide for the resection. Using the burr on reverse allows more precision and decreases the risk of cartilage damage due to aggressive resection.
benefit of magnetic resonance imaging is that it allows for assessment of other aspects of the knee joint, including the integrity of the ACL. Osteophyte formation can result in decreased intercondylar notch volume, which impacts and impinges on the ACL during the extremes of knee extension that could result in ACL injury. This impingement may progress to ACL degeneration and may alter knee biomechanics and proprioception.1,11 However, although the notchplasty procedure and its relation to ACL reconstruction are well Table 2. Advantages and Disadvantages of the Notchplasty Technique Advantages
Disadvantages
This technique improves knee motion in extension and resolves pain due to abnormal gait mechanics. A dynamic evaluation of the impingement ensures the complete resection of the osteophytes. This technique can avoid or delay impingement on the anterior cruciate ligament. Concomitant pathologies can be treated arthroscopically while completing the notchplasty.
Iatrogenic damage to the cartilage and ligaments can occur during resection. Recurrence of the osteophytes and loss of extension may be seen in some patients.
described,2,6,12-17 the effects of notchplasty in the setting of osteoarthritis remain unclear. Leon et al.1 described 4 types of intercondylar stenosis in knees associated with degenerative osteoarthritis based on anatomic findings. These 4 types of intercondylar stenosis included type I, anterior with osteophyte formation leading to damage of the anterodistal part of the ACL; type II, osteophyte formation resulting in damage at the midlateral area; type III, a combination of types I and II, both anterior and midlateral portion damage, which has been shown to be the most prevalent; and type IV, stenosis resulting from a previous massive, complex injury. In all cases, regardless of type, the authors found evidence of knee instability and decreased muscular strength, with 61% presenting with associated loss of knee extension. The notchplasty procedure was successfully performed, restoring knee biomechanics and range of motion. Puddu et al.18 also reported improvement in active extension and a decrease in pain and stiffness of the knee after the removal of the anterior tibial osteophyte and a notchplasty procedure. Moreover, a survey performed with 170 orthopaedic surgeons with more than 10 years of experience and more than 100 arthroscopies performed per year reported that the most interviewees consider notchplasty as a reasonable procedure to address extension deficits associated with intercondylar stenosis, with 14.7% reporting very good and 5.3% reporting excellent results.19 However, Lakdawala et al.,20 the authors that introduced the term “anvil osteophyte,” raised doubts if this tibial bone formation is mainly responsible for the knee flexion deformity and if its resection alone improves outcomes. In summary, the described arthroscopic femoral notchplasty technique allows for restoration of the notch volume, ultimately improving ACL-notch impingement and re-establishing space for the ACL during knee extension. Care during this surgical technique must be taken to avoid iatrogenic damage to the articular cartilage and ligaments in close proximity of this osteoplasty of the femoral intercondylar notch, as well as the anterior meniscal root and ACL attachment during the tibial osteophyte resection. Notchplasty may help to restore knee extension, thereby, improving knee biomechanics and gait. Nevertheless, the outcomes of this procedure related to ACL integrity, restoration of muscular strength, and the length of symptomatic relief urge further study. Therefore, longterm studies with large sample sizes are needed to further assess the efficacy of this procedure.
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