Biological Bone Plate and Iliac Bone Autograft for Proximal Tibial Slope Changing Osteotomy in Genu Recurvatum.

Genu recurvatum (GR) is defined as knee hyperextension greater than 5°, with the normal physiological accepted limits of up to 10 to 15° of extension. Physiological GR is commonly bilateral, symmetrical, and mostly asymptomatic. Pathologic GR is usually asymmetric, symptomatic, and can be congenital or acquired. Acquired GR can be classified according to the origin of the deformity into pure osseous, soft tissue, and combined types. Symptomatic GR can present with anterior knee pain and/or instability. Surgery is generally indicated in symptomatic (pain, instability), pathologic GR with an associated causative correctible deformity (bony, soft tissue, or a combination of both). Tibial slope-reversing osteotomy is indicated for the osseous or mixed types where there is inverted tibial slope. Varu-correcting osteotomy is indicated in the posttraumatic soft-tissue type (posterior and lateral soft-tissue injury as in knee dislocation), the aim of osteotomy is to protect the reconstructed ligaments. No role for osteotomy in the nontraumatic soft tissue type (gradual stretching of the posterior structures). In this article, we describe a technique to correct a unilateral genu recurvatum deformity with inverted tibial slope, mostly due to Osgood-Schlatter disease. Correction is done by performing an anterior open-wedge osteotomy of the proximal tibia and impaction of 2 wedges of autogenous iliac bone grafts within the osteotomy. The proximal portion of the tibia is cut in the coronal plan and is used as a biologic plate for fixation with no need for additional hardware (e.g., plate or staples) for fixation of the osteotomy.

Genu recurvatum (GR) is a knee hyperextension deformity. From Latin, genu: knee and recurvare: to bend back. GR is operationally defined as a knee extension greater than 5°. Although there is no consensus about the limits of “normality” of knee joint extension, Murphey et al. suggest that a knee joint range of motion including 10° to 15° of extension is considered normal, and a knee with more than 15° of extension is considered as “pathologic.” Constitutional “physiological” knee hyperextension of up to 15° has been found to fluctuate from 10% to 25% between Eastern populations and others and is commonly bilateral, symmetrical, and mostly asymptomatic., Pathologic GR is usually asymmetric and can be congenital or acquired. Acquired GR has been classified by Dejour et al. according to the origin into 3 patterns: (1) pure osseous deformity due to tibial tubercle (TT) growth plate damage resulting in inversion of the tibial slope in the sagittal plane. Growth plate damage may result from direct trauma, fractures, osteomyelitis, Osgood-Schlatter disease, or radiotherapy. (2) Soft tissue related. This pattern may be due to trauma or chronic tissue stretching. (3) A mixed type resulting from a combination of both osseous and soft tissue disorders as in poliomyelitis. Moroni et al. described a fourth idiopathic type when the cause is unknown, the clinical presentation of which was symptomatic, bilateral, and symmetrical GR >15°. Idiopathic GR is considered pathologic., Treatment of symptomatic GR can be directed toward the pathologic origin of the condition. Osseous GR can be managed by tibial osteotomy. Soft-tissue GR can be managed by surgical soft-tissue tensioning, muscular strengthening, bracing, and gait pattern correction. Osteotomy in soft-tissue GR pattern is mostly a varus deformity–correcting osteotomy and is directed at protecting the reconstructed ligaments rather than correcting the recurvatum deformity. Mixed-type GR can be managed by osteotomy alone or in combination with soft tissue tensioning procedures.

In this article, we describe a technique to correct a unilateral GR deformity with inverted tibial slope, mostly due to Osgood-Schlatter disease. Correction is done by performing an anterior open-wedge osteotomy of the proximal tibia and impaction of 2 wedges of autogenous iliac bone grafts within the osteotomy. The proximal portion of the tibia is cut in the coronal plan and is used as a biologic plate for fixation with no need for additional hardware (e.g., plate or staples) for fixation of the osteotomy.

Surgical Technique (With Video Illustration)

This article describes step-by-step correction of a GR and a reversed tibial slope by anterior open-wedge high tibial osteotomy and autogenous iliac bone grafting. The upper tibial bone is used as a biological bone plate (Video 1). Advantages and limitations are summarized in Table 1, and pearls and pitfalls are summarized in Table 2.

Table 1

Surgical Steps, Pearls, and Pitfalls of the Technique

Surgical steps	Pearls	Pitfalls
Skin incision	Make it just lateral to the tibial crest.	Direct incision on the tibial shin may jeopardize wound healing.
Proximal tibial exposure	Ensure subperiosteal exposure.Use blunt Hohmann retractors.	Nonmeticulous subperiosteal exposure or using sharp Hohmann retractors will damage the muscles of the anterior compartment or the neurovascular structures.
Osteotomy of the proximal tibia.	Localize the site of cutting with an electrocautery.Use a sharp saw blade.Continually irrigate with saline while cutting with the saw.Wrap the cut fragment with a wet towel and protect it.	If not well localized, this will result in a superficial cut that may easily breaks or an undesired deep cut.Blunt saw blade increases the operative time and increases the incidence of bone necrosis and infection.No irrigation will increase the incidence of thermal bone necrosis and infection.Leaving it exposed will cause it to dry out and become exposed to infection or fracture
Insertion of K-wires for the anterior opening osteotomy	Under image control.Directed proximal to the PCL insertion.Under image control	If not done under image control, it will be inserted inappropriately with liability of posterior knee structures injury.To facilitate the proximal fragment manipulation, avoid any change in the PCL tension, and to obtain a stable hinge.
Making the anterior open wedge osteotomy	Do not violate the posterior cortex and leave a posterior hinge for opening the osteotomy.Use a sharp saw blade.Continually irrigate with saline while cutting with the saw.Put the saw blade in contact and parallel to the K-wires inferiorly. Make the cut inferior to the K-wires leaving the K-wires in the proximal fragment.	If not done under image control, posterior knee structures can be damaged.Cutting the posterior cortex may damage the posterior knee structures and will result in an unstable proximal fragment with inability to open the osteotomy appropriately.A blunt saw blade increases the operative time and increases the incidence of bone necrosis and infection.No irrigation will increase the incidence of thermal bone necrosis and infection.Presence of the K-wires in the proximal fragment prevents intraarticular propagation while opening the osteotomy.
Anterior opening of the osteotomy	Under image control to precisely control the amount of anterior opening and the degree of tibial slope correction.Use a surgical ruler to measure the amount of anterior opening according to the preoperative measurements.Open the osteotomy gradually with the use of a lamina spreader or the insertion of multiple osteotomes.	Without using these tools (image and ruler), the degree of correction will be inappropriate.Rapid opening may break the posterior cortex, resulting in an unstable situation.
Insertion of the iliac graft.	Precisely size the graft according to the desired amount of opening.	Wrongly sized graft wedges will result in an undesired change of the tibial slope.
Repositioning of the anterior tibial fragment	Chamfer any bony prominences with a saw blade before reduction.Anatomically reduce it.	If not done, anatomic reduction will be hindered.If not reduced anatomically, the patellar height may be affected.
Fixation of the anterior fragment	Use proximal and distal screws in a lag manner.	Avoid overpenetration of the posterior cortex with the drill bit or long screws to avoid any injuries of the posterior structures.

PCL, posterior cruciate ligament.

Table 2

Advantages and Disadvantages of the Technique

Advantages	Disadvantages
Bone of the anterior part of the proximal tibia is used as a biological plate. Decreasing the amount of hardware has the advantage of lowering the cost, decreasing the incidence of infection, and reducing the need for future hardware removal.
Using autogenous iliac bone graft has the advantage of decreasing disease transmission associated with allograft. It also is cost-effective compared with artificial bone substitutes.	Increased operative time.Increased patient morbidity.Surgically demanding.

Preoperative Planning

The tibial slope is measured on a lateral view plain radiograph of the knee. A line is drawn tangent with the tibial plateau. Another line is drawn along the posterior tibial cortex and intersects with the plateau line to form the tibial slope angle, which in this case was 79°, denoting a reversed tibial slope. A third is drawn perpendicular to the tibial plateau tangent line to show the needed degrees of correction (Fig 1).

Fig 1

Preoperative planning. Lateral plain radiograph of the left knee. The yellow line is tangent with the tibial plateau. The red line is perpendicular to the yellow line. The blue line is tangent with the posterior tibial cortex and intersects with the yellow line making the tibial slope angle, which in this case was 79°, denoting a reversed tibial slope, Osgood-Schlatter disease of the tibial apophysis (yellow arrow).

Patient Position and Surgical Landmarks

After induction of anesthesia, the patient is placed in the supine position. Landmarks for arthroscopic and surgical work are drawn (Fig 2). The patient is examined under anesthesia. A high thigh nonsterile padded tourniquet is then applied. The patient is then prepared and draped in the usual manner. A tricortical autogenous iliac graft is taken and prepared.

Fig 2

Patient position and surgical landmarks. Front image of the left knee while the patient supine and the knee are extended, showing the landmarks for performing knee arthroscopy and open correction of the recurvatum deformity. (HALP, high anterolateral portal; PT, patellar tendon and the patella; TT, tibial tuberosity.).

Knee Arthroscopy

Routine knee arthroscopy is performed (Hopkins II; Karl-Storz, Tuttlingen, Germany). Any chondral or meniscal pathology is managed.

Surgical Technique

A 10- to 15-cm surgical incision is made on the anterior aspect of the tibia just lateral to the tibial shin and starting just proximal to the tibial tuberosity (Fig 3A). Muscles on the anterolateral aspect of the proximal tibia are lifted subperiosteally to expose the proximal tibia (Fig 3B). The site of osteotomy is marked with an electrocautery (Fig 3C). While Hohmann retractors are placed subperiosteally, the bone of the proximal tibia is cut horizontally with a saw blade. The bone cut is completed with an osteotome to create a bone segment of about 15 cm long (biological bone plate). The bone segment is reflected proximally and wrapped with a wet towel (Fig 4 A-D).

Fig 3

Steps of surgical exploration of the proximal tibia of the left knee while the patient is supine. (A) Front image of the left knee while the patient supine and the knee extended. A 10- to 15-cm surgical incision is made on the anterior aspect of the tibia just lateral to the tibial shin and starting just proximal to the tibial tuberosity. (B) Muscles on the anterolateral aspect of the proximal tibia are lifted off subperiosteally to expose the proximal tibia. (C) The site of osteotomy is marked with an electrocautery. (PT, patellar tendon and the patella; TT, tibial tuberosity.).

Fig 4

Steps of creating the biological bone plate (10-15 cm long) by performing an osteotomy of the proximal tibia of the left knee in the coronal plan. (A-B) Front image of the left knee while the patient is supine and the knee extended. While Hohmann retractors are placed subperiosteally, the bone of the proximal tibia is cut horizontally with a saw blade. (C) The bone cut is completed with an osteotome to create a bone segment of about 15 cm long (biological bone plate). (D) The bone segment is reflected proximally and wrapped with a wet towel.

Under image control, 2 parallel K-wires are inserted in the proximal tibia from anterior to posterior at the desired osteotomy site and directed to a point just proximal to the posterior cruciate ligament insertion (Fig 5 A and B).

Fig 5

Insertion of K-wires at the site of osteotomy. (A) Front image of the left knee while the patient is supine. Two parallel K-wires are inserted in the proximal tibia from anterior to posterior at the desired osteotomy site and directed to a point just proximal to the posterior cruciate ligament insertion. (B) Fluoroscopic lateral view of the left knee taken intraoperatively as Image control is mandatory to precisely locate the k-wires.

Under image control, the bone is cut with a saw blade from anterior to posterior, parallel, and inferior to the inserted K-wires to avoid intra-articular propagation while opening the osteotomy. Care is taken not to cut the posterior tibial cortex and leave about 5 mm of bone from the posterior cortex as a hinge for the osteotomy (Fig 6 A and B).

Fig 6

Performing the anterior open-wedge correcting osteotomy. (A) Front image of the left knee while the patient is supine showing a saw blade used to perform the bone cut from anterior to posterior, guided by the previously inserted K-wires. (B) Fluoroscopic lateral view of the left knee taken intraoperatively as image control is mandatory to control the bone cut that is made by a saw blade from anterior to posterior, parallel and inferior to the inserted K-wires to avoid intra-articular propagation while opening the osteotomy. Care is taken not to cut the posterior tibial cortex and leave about 5 mm of bone from the posterior cortex as a hinge for the osteotomy.

Under image control, the osteotomy site is opened by the sequential insertion of multiple osteotomes (Fig 7 A and B). The amount of anterior wedge opening is measured according to the preoperative plan (Fig 7C).

Fig 7

Opening the correction osteotomy. (A) Front image of the left knee while the patient supine and the knee flexed showing anterior opening of the osteotomy by the sequential insertion of multiple osteotomes. (B) Fluoroscopic lateral view of the left knee taken intraoperatively as to control the amount of osteotomy opening and avoiding posterior cortex violation. (C) Front image of the left knee while the patient supine and the knee flexed, the amount of anterior wedge opening is measured according to the preoperative plan.

Two wedges of autogenous iliac bone graft are shaped according to the desired correction size and are inserted to fill the osteotomy gap (Fig 8 A-D). Any bone prominence is chamfered with the saw, then the bone plate is reduced and fixed with small fragment lag screws proximal and distal to the osteotomy (Fig 9 A- E). Stability is checked, the wound is closed, and the knee is put in a brace.

Fig 8

Impaction of the autogenous iliac graft into the osteotomy site. (A) A saw blade is used to cut the autogenous iliac bone graft into two wedges of bone. (B) Two wedges of autogenous iliac bone graft are shaped according to the desired correction size. (C) Front image of the left knee while the patient supine and the knee flexed showing the impaction of the 2 bone wedges into the osteotomy gap. (D) Fluoroscopic lateral view image of the left knee taken intraoperatively showing the corrected tibial slope after the impaction of the bone wedges.

Fig 9

Reduction and fixation of the biological bone plate. (A) Front image of the left knee while the patient is supine and the knee flexed. Any bony prominence is chamfered with the saw. (B) Reduction of the bone plate. (C) Fixation of the bone plate with small fragment lag screws proximal and distal to the osteotomy. (D) Intraoperative lateral image of the left knee showing correction of the deformity and final fixation. (E) Intraoperative anteroposterior image of the left knee showing correction of the deformity and final fixation.

Discussion

Coronal plane deformities in the proximal tibia are the most commonly treated deformities and varus- or valgus-producing high tibial osteotomies have been well described in the literature. Sagittal plane deformities, however, have not gained as much attention due to their relatively uncommon presentation and necessity for surgical management.

The most common presentations of patients with GR are anterior knee pain, knee instability, patellofemoral instability, and difficult walking on an uneven ground.,

The exact cause of anterior knee pain is not well known; however, this may be related to chronic inflammation and impingement of the hypertrophied fat pad behind the patella when the knee is extended.

A recurvatum knee is inherently very unstable. Knee instability usually results from the dysfunction of the locking mechanism, quadriceps wasting, and abolition of the patellofemoral lever arm. Pseudo-patella alta in a recurvatum knee is the likely cause of patellofemoral instability.

It may be difficult to decide whether or not to operate on a recurvatum knee. Knee hyperextension is not itself abnormal. Constitutional hyperextension of the knee of up to 15° has been found to be physiological in 40% of the population of normal control and is commonly bilateral, symmetrical, and asymptomatic. No intervention is needed for constitutional hyperextension of the knee.,,

Surgery is generally indicated in the symptomatic (pain, instability), pathologic GR with an associated causative correctible deformity (bony, soft tissue, or a combination of both). More specifically, osteotomy is indicated when there is a pure bony cause for the GR (i.e., reverse of the tibial slope). The tibial slope can be reversed due to damage of the TT physis for any reason, e.g., trauma, fracture, osteomyelitis, patellar tendon graft harvesting before skeletal maturity, Osgood-Schlatter disease, prolonged immobilization, or radiotherapy. Another rare bony factor is hypoplasia of the lateral femoral condyle resulting in hyperextension of the tibia together with excessive external rotation and subluxation of the tibia on the femur.,

Osteotomy is indicated also in the mixed-type GR (bony and soft tissue) as in poliomyelitis. The problem starts with bony changes as the patient has a weak quadriceps and subsequently hyperextends his or her knee to lock it while walking. Knee hyperextension results in reversing the tibial slope followed by gradual stretching of the posterior soft tissues and unstable knee. However, in these patients, the recurvatum should not be overcorrected to preserve the passive lock-home stabilizing mechanism.,,

Pure soft-tissue GR may be traumatic in origin (e.g., following posterior knee dislocation) or nontraumatic (gradual stretching of the posterior structures). Osteotomy alone has a much lesser role in the pure soft-tissue pattern and is mainly a varus correcting osteotomy done to protect the reconstructed ligaments.

Many types of osteotomy techniques have been described in the literature to correct bony recurvatum. Irwin described a posterior- closing wedge osteotomy below the level of the TT with fibular osteotomy. Bowen et al. described a posterior closing-wedge osteotomy above the level of the TT.

Anterior opening-wedge osteotomy may be done proximal to the TT, as described by Lexer, Bohn, and Brett, at the level of the TT with tibial tubercle osteotomy as described by Lecuire et al., or distal to the TT as described by Campbell.

Generally speaking, osteotomies below the TT are associated with low healing potential, with the osteotomy level being far from the site of bony deformity, necessitating a greater angular correction and adding a fibular osteotomy. Osteotomies above the TT are close to the site of deformity; however, the epiphyseal fragment is small, prone to necrosis, and with a less-stable posterior hinge. This type of osteotomy affects the patellofemoral functions.

Our technique is performed by making an anterior opening-wedge osteotomy at the level of the TT with a posterior hinge situated just proximal to the posterior cruciate ligament insertion. This site of osteotomy in the metaphyseal bone has a high healing potential, close to the site of deformity, and does not affect the patellofemoral functions. A long segment of the proximal tibia is cut in the coronal plane and is used as a biological plate for osteotomy fixation.

Many implants have been used for fixation of the osteotomy as staples or plates., In our technique, we used a long segment of the proximal tibia as a biological plate for osteotomy fixation.