Editorial Commentary: The Medial Patellofemoral Complex Is Composed of the Medial Patellofemoral Ligament and the Medial Quadriceps Tendon–Femoral Ligament: Do We Need to Reconstruct Both?

The medial patellofemoral ligament (MPFL) has been known as the primary soft-tissue restraint to lateral patellar translation. More recent anatomic studies have identified additional fibers that extend to the quadriceps tendon (medial quadriceps tendon–femoral ligament [MQTFL]), leading to the use of the term “medial patellofemoral complex” (MPFC) to describe the broad and variable attachment of this complex on the patella and quadriceps tendon. Whereas many techniques and outcomes of traditional MPFL reconstruction have been described, fewer reports exist on anatomic MPFC reconstruction to recreate both bundles of this complex. To date, the specific biomechanical roles of, and indications for, reconstruction of the MPFL versus MQTFL fibers have not been defined. One primary benefit of MQTFL reconstruction has been to avoid the risk of patella fracture, which is not obviated in the setting of concurrent patellar fixation when reconstructing both components of the MPFC. The risks and benefits comparing fixation on the patella, quadriceps tendon, or both with anatomic double-bundle reconstruction remain to be determined. Additional studies are needed to understand the differences between reconstructing the proximal and distal fibers of the MPFC with regard to graft length changes and femoral attachment sites, in order to optimally recreate the function of each graft bundle in the surgical treatment of patellar instability.     

Medial Patellofemoral Reconstruction Techniques for Patellar Instability

The medial patellofemoral complex (MPFC) is the term used to describe the primary soft tissue stabilizer of the patella, which consists of fibers that attach to the patella (medial patellofemoral ligament, or MPFL), and the quadriceps tendon (medial quadriceps tendon femoral ligament, or MQTFL). Despite the variability of its attachment on the extensor mechanism, the midpoint of this complex is consistently at the junction of the medial quadriceps tendon with the articular surface of the patella, indicating that either patellar or quadriceps tendon fixation can be used for anatomic reconstruction. Multiple techniques exist to reconstruct the MPFC, including graft fixation on the patella, quadriceps tendon, or both structures. Various techniques using several graft types and fixation devices have all reported good outcomes. Regardless of the location of fixation on the extensor mechanism, elements critical to the success of the procedure include anatomic femoral tunnel placement, avoiding placing undue tension on the graft, and addressing concurrent morphological risk factors when present. This infographic reviews the anatomy and techniques for the reconstruction of the MPFC, including graft configuration, type, and fixation, while addressing common pearls and pitfalls in the surgical treatment of patellar instability.     

Medial Patellofemoral Ligament Reconstruction: Indications,Technique, and Outcomes

The medial patellofemoral ligament is the primary static restraint to lateral patellar translation. It is injured in 96% to 100% of patellar dislocations that affect approximately 6 to 29 of 100,000 patients and is more common in patients younger than 20 years of age. Risk factors for patellar dislocation include patella alta, trochlear dysplasia, genu valgus, increased Q angle, and hyperlaxity. The treatment for patellar instability depends on the clinical and radiographic findings and can be nonoperative for first-time dislocations (bracing, proximal strengthening, and progressive return to sport) or operative for recurrent dislocations. It is critical for medial patellofemoral ligament reconstruction to reproduce the anatomy and isometry of the native ligament. Graft choice and methods of fixation are less critical to achieve successful outcomes. Studies have reported successful outcomes and improved Kujala scores, with recurrent instability ranging from 1% to 5%. Careful surgical technique can avoid complications, including fracture, graft failure, loss of range of motion, persistent anterior knee pain, medial instability, and recurrent instability. The role of the medial quadriceps tendon femoral ligament also should be considered more in future research.     

Reconstruction of the Medial Patellofemoral Ligament With Autologous Quadriceps Tendon

In knees with insufficient or previously disrupted medial retinacular and patellofemoral ligaments caused by subluxation or dislocation, anatomic reconstruction of the medial patellofemoral ligament may be performed. This procedure involves harvesting of an 8 × 70-mm medial quadriceps tendon graft, which leaves the quadriceps tendon retinacular attachment intact and avoids patellar and femoral drill holes. This graft is passed beneath the retinaculum adjacent to the femoral epicondyle and is sutured to the medial intermuscular septum—a procedure that reproduces the medial patellofemoral ligament and is supported by imbrication of the remaining medial retinaculum. The tension of the graft and of the medial retinaculum is set at closure with the knee in 30° to 45° of flexion; this allows the patella to be moved a distance equal to 25% of its width. Avoidance of drill holes allows the procedure to be used regardless of skeletal maturity and reduces fracture complications, inadequate graft placement, and failure of fixation. Postoperative rehabilitation includes immediate knee motion from 0° to 90° and partial weight bearing.     

Editorial Commentary: The Best Medial Patellofemoral Reconstruction May Include Components of Both Quadriceps and Patellar Attachments

Given different functions of the medial quadriceps tendon–femoral ligament and medial patellofemoral ligament components of the proximal medial patellar restraints, reconstructions to the midpoint of the medial patellofemoral ligament and medial quadriceps tendon–femoral ligament are probably optimal, combining the benefits of both in surgical treatment of recurrent patella instability.     

Medial Patellofemoral Ligament Reconstruction: A Novel Technique Using the Patellar Ligament

In patients with chronic patellofemoral instability, more than 2 episodes of dislocation, and an anterior tuberosity trochlear groove of less than 20 mm as measured on computed tomography or nuclear magnetic resonance imaging, we have developed a technique for medial patellofemoral ligament reconstruction that uses a medial strip of the patellar ligament (PL). The incision started proximally at the level of the superior margin of the patella, centrally between the patellar medial margin and the medial epicondyle. A descending incision was then made, directed toward the superomedial margin of the tibial tubercle. We performed a plane-by-plane dissection up to the peritenon of the PL. With an osteotome, we could remove a 2-cm bone fragment concerning the medial third of the distal insertion of the PL or keep the distal end free. Using a No. 11 scalpel blade, we carefully detached the PL from the patella up to the transition between the proximal third and medial third of the patella. We placed the stitches between the periosteum and the ligament using FiberWire absorbable threads (Arthrex, Naples, FL) to safely rotate the graft. After that, we dissected the medial capsule and approached the femoral medial epicondyle. Then we placed a Krackow suture in the free tendon end using absorbable threads or anchored the threads into 2 holes that were previously drilled, and we secured the end with an absorbable interference screw or anchors. The fixation should be performed with the knee at 15° to 30° of flexion. Then we sutured the distal edge of the vastus medialis muscle to the graft, which bestows a dynamic component upon the reconstruction, and we immobilized the knee with a removable brace.     

Editorial Commentary: The “F” in MPFL (Medial Patellofemoral Ligament) Reconstruction—How Should We Fix It and Does It Matter?

Our understanding of the medial patellofemoral complex anatomy has evolved significantly over the past several decades, and this has informed our current surgical approach to management of lateral patellar instability. Medial patellofemoral ligament reconstruction remains the gold standard for decreasing the risk of secondary patellar dislocation and returning patients to active physical function. However, concerns about isometry, overconstraint, secondary arthrosis, and surgical-site morbidity remain with femoral socket fixation, particularly when patella alta, rotational malalignment, or hypermobility is present. Medial patellofemoral ligament reconstruction with soft-tissue fixation, on either the patellar or femoral side, may mitigate some of these risks by offering a more dynamic checkrein to lateral translation. However, longer-term studies are required to determine comparative efficacy with varying surgical techniques, and the ideal graft tension and degree of knee flexion during fixation have not yet been determined.     

Simultaneous Reconstruction of Ruptured Anterior Cruciate Ligament and Medial Patellofemoral Ligament With Ipsilateral Quadriceps Grafts

Rupture of the anterior cruciate ligament is a well-known entity and causes anteroposterior and rotational instability of an injured knee. Rupture of the medial patellofemoral ligament is less frequent, and its insufficiency causes patellar instability. Several techniques have been described for the reconstruction of each ligament. The 2 lesions and following instabilities can coexist, and both ligaments can be reconstructed simultaneously. We report on 2 cases, 1 recreational sportswoman and 1 high-level sportswoman, with coexisting lesions treated surgically by a single-step procedure using ipsilateral graft of the quadriceps tendon for reconstruction of medial patellofemoral ligament and anterior cruciate ligament. The advantage of this procedure is that there is only 1 donor site, and thus lower donor-site morbidity, while the strength of either neoligament is not sacrificed. The technique is described here.     

Technical Failure of Medial Patellofemoral Ligament Reconstruction

In patients with chronic patellofemoral instability who have normal alignment and deficient proximal medial restraints, medial patellofemoral ligament (MPFL) reconstruction is a good option to treat patellar instability. However, medial subluxation, medial patellofemoral articular overload, and recurrent lateral instability are possible when the graft is positioned non-anatomically. The clinical presentation of MPFL femoral tunnel malpositioning has not been highlighted in the literature. We have had 5 patients referred to us after a malpositioned femoral MPFL graft led to disabling symptoms and a need for revision surgery. This report highlights the effects of a malpositioned graft and describes strategies to identify the anatomic MPFL insertion during surgery.     

内侧髌股韧带联合髌胫韧带重建治疗复发性髌骨脱位

目的评价用半腱肌腱重建内侧髌股韧带和用髌韧带内1/3重建髌胫韧带治疗复发性髌骨脱位的临床疗效和影像学结果。方法回顾性分析我科2013年6月至2018年6月收治的25例复发性髌骨脱位患者,其中男性6例,女性19例;年龄15~38岁,平均(22.36±5.20)岁。全部患者均在麻醉下取半腱肌肌腱重建髌股韧带,取髌韧带内1/3带胫骨结节骨块重建髌胫韧带。术后复查CT和X线,测量髌骨-股骨适配角、髌骨倾斜角,髌骨外移度、Caton指数、胫骨结节-股骨滑车沟(tibial tubercle-trochlear groove,TT-TG)距离值作为影像学评价;以膝关节功能Lyshlom评分、Kujala评分、J形征和恐惧试验作为临床疗效评价。结果25例患者均获得随访,随访时间12~48个月,平均(18.16±6.85)个月。患者术后均未再次脱位。Kujala评分:术前(54.60±11.08)分,术后(75.40±7.49)分;Lysholm评分:术前(43.48±6.78)分,术后(93.20±3.52)分;手术前后比较差异有统计学意义(P<0.05)。影像学检查结果提示,髌骨-股骨适配角:术前(13.74±5.09)°,术后(4.14±2.52)°;髌骨倾斜角:术前(16.89±4.09)°,术后(3.40±1.37)°;髌骨外移度:术前(33.14±3.99)mm,术后(7.40±2.69)mm;手术前后比较差异有统计学意义(P<0.05)。TT-TG值、Caton指数手术前后比较差异无统计学意义(P>0.05)。查体J形征阴性,恐惧试验阴性。结论本研究采用半腱肌肌腱重建髌股韧带联合髌韧带内1/3重建髌胫韧带治疗复发性髌骨脱位,在技术上是安全,可在短期随访时间内取得良好的临床效果。     

Medial patellofemoral ligament reconstruction: a novel approach

Recurrent patellar instability is common, and multiple procedures have been described for its treatment. Medial patellofemoral ligament reconstruction can be successful in patients who have an incompetent medial patellofemoral ligament or who have failed medial patellofemoral ligament repair and present with recurrent patellar instability. This article describes a novel approach to medial patellofemoral ligament reconstruction using a folded hamstring allograft with a new knotless suture anchor and bio-interference screw fixation. The principal advantage of this construct is the ability to definitively fix the medial patellofemoral ligament soft-tissue graft on the femur and provisionally fix the graft to the patella while assessing for reasonable medial patellofemoral ligament isometry throughout the arc of knee motion.     

改良髌骨双骨道法自体股薄肌腱重建髌骨内侧支持带治疗复发性髌骨脱位

目的探讨改良髌骨双骨道法自体股薄肌腱重建髌骨内侧支持带（medial patellofemoral ligament,MPFL）治疗复发性髌骨脱位的临床效果,同时探讨解剖高危因素对术后效果的影响。方法2007年1月-2010年2月,对36例髌骨复发性脱位（单侧31例,双侧5例）采用改良髌骨双骨道法自体股薄肌腱重建MPFL,在髌骨内上缘由后内向前外向髌骨内1／2表面平行钻2个3．5mm骨道,将股薄肌腱引过骨道,将股薄肌腱的两游离端拉入股骨内侧骨道,屈膝30。位可吸收螺钉固定。对所有患者的Beighton评分,Q角,Insall指数,滑车发育不良分级,胫骨结节一滑车沟距离（TT—TG）等进行测量。临床评分采用Kujala,Lysholm和Tegner评分,同时调查患者的满意度。结果32例对手术的效果非常满意,3例满意,1例不满意。Kujala、Lysholm、Tegner评分分别由术前（64．34-15．0）、（65．1±18．6）、（3．2±1．1）分显著提高到术后（92．4±9．2）分（t=4．657,P=0．002）,（92．0±10．1）分（t=3．936,P=0．006）和（5．2±1．0）分（t=6．633,P=0．001）。80．6％（29／36）的患者在术后6—8个月恢复到受伤前的运动水平。1例术后1年再次髌骨脱位。97．6％（40／41）的膝关节存在股骨滑车发育不良,Beighton评分（5．2±2．5）分,Insall指数为1．22±0．14,Q角（13．6±3．9）°,TT-TG值（13．7±4．4）mm,与功能评分无相关性（P〉0．05）。结论自体股薄肌腱改良髌骨双骨道法重建MPFL是一种可靠安全经济的手术方法。高危解剖因素如高位髌骨、滑车发育不良、关节松弛等情况广泛存在于髌骨复发性脱位的患者中,虽未发现其严重程度会直接影响手术效果,但当复合因素存在时,仅重建MPFL的软组织手术可能不足以完全防止髌骨脱位复发。     

Medial patellofemoral ligament reconstruction with gracilis autograft for patellar instability

We describe a technique for patellar stabilization by reconstruction of the medial patellofemoral ligament with the gracilis tendon. The tendon is anchored posteriorly on the soft tissue of the medial femoral epicondyle and anteriorly on the medial border of the patella. The plasty is completed by suture of the medial patellar wing. Inferior or medial transposition of the tibial tubercle may be associated. We have used this technique since 1995 for 145 knees with patellar instability. The small incisions have the advantages of minimally invasive surgery, particularly for the postoperative period and the cosmetic effect.     

Editorial Commentary: The Medial Patellofemoral Ligament Is Not Isometric and Anatomic Reconstruction Is Important,But Just a Small Piece of the Patellar Instability Puzzle

Medial patellofemoral ligament (MPFL) reconstruction has proven to be a reliable procedure to reduce patellar instability events in patients with recurrent patellar instability. As our reconstruction techniques have evolved to address pathology in a diverse patient population, there continues to be an obsessive focus on the precise anatomy of the MPFL origin on the medial knee, due in large part to concerns that improper femoral tunnel position may result in excessive graft anisometry and failure. However, recurrent patellar instability involves many complexities and should not be simply reduced to a single point on the medial knee.     

A technique for reconstruction of the medial patellofemoral ligament

Additional medial patellofemoral ligament reconstruction was performed successfully on six consecutive patients with recurrent dislocation of the patella because of residual patellar instability after medial transfer of the tibial tubercle. A technique for medial patellofemoral ligament reconstruction is described, and complications and postoperative management are discussed. The reconstruction was performed using a double strand hamstring tendon graft in five patients and iliotibial allograft in one. Good stabilization of the patella was achieved in all six patients, resulting in improved confidence in higher levels of activity. The satisfactory outcome of additional medial patellofemoral ligament reconstruction suggests the possibility that the procedure may be part of the optional procedure in proximal realignment for recurrent dislocation of the patella.     

Editorial Commentary: Socket or Knock It? Considerations in Patellar Fixation During Medial Patellofemoral Ligament Reconstruction

The medial patellofemoral ligament (MPFL) is the primary static stabilizer to lateral patellar translation, and reconstruction of this ligament has been shown to be successful in reducing dislocation rates and improving functional outcomes in the treatment of patellar instability. Recent studies have warned that complication rates after MPFL reconstruction can be as high as 25%, with patellar fracture being one of the most catastrophic complications that can occur after this procedure. While the use of a bone socket versus cortical fixation on the patella does not appear to influence outcomes, surgeons should take into account the factors of graft and tunnel positioning, graft length/tension, and the need for concurrent procedures in each individual patient when performing this procedure. Any violation of the patella, whether as a socket or for anchor placement, should avoid the anterior cortex and maintain an adequate bony bridge that should be modified according to the patient's anatomy. The optimal technique for MPFL reconstruction continues to evolve, and further studies are needed to identify the ideal type and position of patellar fixation to minimize risks of complications and optimize surgical outcomes when performing MPFL reconstruction in the treatment of patellar instability.     

Editorial Commentary: Medial Patellofemoral Ligament Repair Versus Reconstruction: Still a Question or a Clear Winner?

Controversy persists regarding appropriate treatment of patellar instability. As surgeons move to a more aggressive approach, medial imbrication and medial patellofemoral ligament repair are waning in popularity whereas medial patellofemoral ligament reconstruction has become the standard of care. Techniques vary between surgeons, and consensus remains elusive.     

Anterior Cruciate Ligament Reconstruction

The bone-patellar tendon-bone has been widely used and considered a good graft source. The quadriceps tendon was introduced as a substitute graft source for bone-patellar tendon-bone. We compared the clinical outcomes of anterior cruciate ligament reconstructions using central quadriceps tendon-patellar bone and bone-patellar tendon-bone autografts. We selected 72 patients who underwent unilateral anterior cruciate ligament reconstruction using bone-patellar tendon-bone between 1994 and 2001 and matched for age and gender with 72 patients who underwent anterior cruciate ligament reconstruction using quadriceps tendon-patellar bone. All patients were followed up for more than 2 years. We assessed anterior laxity, knee function using the Lysholm and International Knee Documentation Committee scores, and quadriceps strength, the means of which were similar in the two groups. More patients (28 or 39%) in the bone-patellar tendon-bone group reported anterior knee pain than in the quadriceps tendon-patellar bone group (six patients or 8.3%). Anterior cruciate ligament reconstruction using the central quadriceps tendon-patellar bone graft showed clinical outcomes comparable to those of anterior cruciate ligament reconstruction using the patellar tendon graft, with anterior knee pain being less frequent in the former. Our data suggest the quadriceps tendon can be a good alternative graft choice. LEVEL OF EVIDENCE: Level III Therapeutic study.     

A minimally invasive medial patellofemoral ligament arthroscopic reconstruction

The medial patellofemoral ligament reconstruction is recognized as a good choice for patients with recurrent patellar dislocation. Most techniques of the medial patellofemoral ligament reconstruction are open surgeries. Recently, we present a minimally invasive medial patellofemoral ligament arthroscopic reconstruction technique as a possible alternative method for recurrent patellar dislocation. The aim of the study was to describe a safe and effective technique to perform medial patellofemoral ligament reconstruction. The graft was prepared in shape to “Y.” Two 5-mm incisions were made in the skin above the medial edge of the patella. Two docking bone tunnels were drilled from medial edge to the center of the patella, mimicking the wide patellar insertion of the medial patellofemoral ligament, and a bone tunnel was made at the femoral insertion site. Two free ends of the graft were fixed into the patellar tunnels by lateral cortical suspension, and the folded end was fixed into the femoral tunnel by bioabsorbable interference screw. Average patellar tilt and the congruence angle were 30.7° ± 7.5° and 52.7° ± 7.3° and were reduced to 12.8° ± 0.9° and 2.3° ± 11.5° after treatment. The Kujala score was increased from 63.0 ± 9.0 to 91.0 ± 7.0. The minimally invasive medial patellofemoral ligament arthroscopic reconstruction in this paper seems to be helpful to increase safe of operation and treatment effect and reduce complications.     

内侧髌股韧带重建术治疗复发性髌骨脱位的疗效研究

目的探讨游离肌腱移植重建内侧髌股韧带的手术方法及治疗复发性髌骨脱位的疗效。方法自2006年6月至2012年7月收治复发性髌骨脱位患者共40例（47膝）,男10例（12膝）,女30例（35膝）,年龄7～51岁,平均19．4岁。全部经膝关节镜检最后确诊,其中43膝采用游离自体半腱肌,4膝采用异体肌腱,通过髌骨双隧道移植重建内侧髌股韧带,镜下动态调整移植肌腱的张力,使髌股关节对合达到正常,并用挤压螺钉将肌腱游离端固定在股骨止点。其中8例（10膝）同时行髌韧带止点内移术。结果有36例（42膝）患者获得随访,随访时间3—70个月,平均随访23个月。临床疗效评价包括髌骨主观稳定性评估、Lysholm膝关节评分及Insall疗效标准（1976年）。术后髌骨外推试验和恐惧试验均为阴性。手术前后Lysholm评分术前平均为（63．1±9．1）分,术后评分为（87．1±6．4）分,手术前后的差异有统计学意义（t=21．7,P〈0．05）。按Insall疗效标准,优良率为85．7％。结论采用以游离肌腱重建MPFL为主的综合术式治疗复发性髌骨脱位,手术效果满意。