Skeletal Malalignment and Anterior Knee Pain: Rationale, Diagnosis, and Management

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11 Skeletal Malalignment and Anterior Knee Pain: Rationale, Diagnosis, and Management

Robert A. Teitge and Roger Torga-Spak

Introduction Association of Skeletal Any variation from optimal skeletal alignment Malalignment and Patellofemoral may increase the vector forces acting on the patellofemoral joint causing either ligament fail- Joint Pathology ure with subsequent subluxation or cartilage Abnormal skeletal alignment of the lower failure as in chondromalacia or arthrosis or both extremity has been associated with various ligament and cartilage failure (Figure 11.1). patellofemoral syndromes and biomechanical Anterior knee pain may result from these abnor- abnormalities. Our understanding of these asso- mal forces or their consequences. ciations continues to develop as many refer- The mechanical disadvantage provided by a ences consider only one aspect of the analysis. skeleton with a geometrical or architectural flaw In the frontal plane, malalignment has been distributes abnormal stresses to both the liga- shown to influence the progression of patello- ments and the joints of the misaligned limb. femoral joint arthritis.4,12 Varus alignment Ligament overload and subsequently failure increases the likelihood of medial patello- (insufficiency) may occur with a single traumatic femoral osteoarthrosis progression while valgus episode as well as repetitive episodes of minor alignment increases the likelihood of lateral trauma or chronic overload. Skeletal malalign- patellofemoral osteoarthrosis progression. ment may cause chondromalacia patella and Fujikawa13 in a cadaveric study found a marked subsequently osteoarthritis by creating an alteration of patellar and femoral contact areas increased mechanical leverage on the with the introduction of increased varus align- patellofemoral joint that can exceed the load ment produced by a varus osteotomy. capacity of the articular cartilage. A reduction in Lerat et al.30 noted a statistically significant contact surface area such as a small patella or a correlation between increased femoral internal high patella or a subluxed patella may also torsion and both patellar chondropathy and increase the unit area loading beyond the load instability. Janssen23 also found patellar disloca- capacity of the articular cartilage, leading to car- tion was most commonly combined with tilage failure (osteoarthritis). increased medial torsion of the femur and spec- Anterior knee pain in association with bony ulated that this medial torsion was responsible malalignment may be the result of the abnormal for the development of dysplasia of the trochlea tension or compression placed on the capsule, and of the patella. Takai et al.41 measured ligaments, synovium, or subchondral bone. femoral and tibial torsion in patients with

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186 Etiopathogenic Bases and Therapeutic Implications

Skeletal Malalignment

Increased Forces (Overload)

Ligament Cartilage (Overloaded) (Overloaded)

Subluxation Chondromalacia Dislocation Arthrosis

PAIN

Figure 11.1. Pathogenesis of anterior knee pain.

patellofemoral medial and lateral unicompart- be emphasized that the Q-angle is a normal mental osteoarthrosis and noted that the corre- and necessary anatomic fact responsible for lation of patellofemoral osteoarthritis with balancing the tibiofemoral force transmission. increased femoral torsion (23° vs. 9° in controls) Hvid et al.19 demonstrated a significant rela- was statistically their most significant observa- tion between the Q-angle measurement and tion and suggested that excessive femoral tor- increased hip internal rotation, thus supporting sion is one of the contributory causes of the existence of a torsional malalignment syn- patellofemoral wear. drome of the patellofemoral joint. Insall20 called Turner43 studied the association of tibial tor- an increased Q-angle “patellar malalignment” sion and knee joint pathology and observed that and noted that it was usually associated with patients with patellofemoral instability had increased femoral anteversion and external tib- greater than normal external tibial torsion (25° ial torsion so that the motion of the knee vs. 19°). Eckhoff et al.11 found the tibia in the occurred about an axis that is rotated medially extended knee to be 6° more externally rotated compared with the axes of the hip and ankle than normal controls in a group of patients with joints, producing “squinting” patella. This type anterior knee pain. This was termed knee ver- of knee he stated is prone to chondromalacia sion. Whether this represents an abnormal (clinically “a diffuse aching pain on the antero- skeletal torsion or an abnormal rotation of the medial aspect of the knee”). It should be noted, tibia on the femur due to knee joint soft tissue however, that an increased Q-angle was present laxity or abnormal muscle pull is unknown. in only 40 of 83 (48%) knees in which surgical These studies and many others clearly show realignment for chondromalacia was per- the importance of abnormal skeletal alignment formed. Thus, the problem is not the value of of the lower extremity in the pathogenesis of the Q-angle; the problem is that the Q-angle various disorders of the patellofemoral joint. rotates around the coronal plane of the lower extremity. Q-Angle and Skeletal Malalignment Finally, it should be perhaps mentioned that The Q-angle has been implicated as a major Greene et al.15 showed the reliability of the Q-angle source of patellofemoral pathology, but it must measurement to be poor. Ch11.qxd 10/07/05 7:20 PM Page 187

Skeletal Malalignment and Anterior Knee Pain 187 Definitions: Patellofemoral (Table 11.2). In the frontal plane one can measure varus or valgus and patellar height. In the Alignment sagittal plane one can measure the patellar There are two common uses for the term align- height, distance from the knee joint axis to the ment: (1) malposition of the patella on the patella, depth of the trochlea, and height of the femur, and (2) malposition of the knee joint tibial tubercle. In the horizontal plane one can between the body and the foot with the subse- measure the torsion of the acetabulum, femur, quent effect on the patellofemoral mechanics. tibia and foot, the version of the knee, the posi- While it is more common to consider the position of the tibial tubercle relative to the trochlear tion of the patella in the trochlea (i.e., subluxa- groove, and the depth of the groove as well as tion), this view inhibits the more important the “patellofemoral alignment.” consideration of what the position of the knee in space relative to the center of gravity of the body Diagnosis of Skeletal Alignment has in developing the force that the patello- Malalignment refers to a variation from the nor- femoral joint will experience. Tracking is the mal anatomy; normal is that which is biome- change in position of patella relative to the chanically optimal. In order to detect and femur during knee flexion and extension, and understand deformities of the lower extremity, while it is obviously important no clinically use- it is important to establish the limits and param- ful tracking measurement systems exist and the eters of normal alignment based on average val- loading characteristics of the patellofemoral ues for the general population. joint are largely unrelated to tracking. The relationship of the patella to the femur Frontal Plane Alignment (patellar malalignment) must be viewed in all Frontal plane alignment is best determined three planes (Table 11.1). In the coronal plane, using longstanding AP radiographs including one can measure Q-angle and patellar spin. In hip, knee, and ankle joint. To determine the the sagittal plane one can measure patellar flex- mechanical axis a line is drawn from the center ion and height; in the horizontal plane one can of the femoral head to the center of the ankle measure patellar tilt or shift. Lauren26 noted that joint (Figure 11.2). Typically, normal alignment shift and mini-tilt may both be manifestations of is defined as the mechanical axis passing just decreased lateral facet cartilage. medial to the center of the knee.34 Valgus align- It is a common mistake to consider alignment ment refers to the mechanical axis passing lat- as referring only to the position of the patella on eral to the center of the knee while varus refers the femoral trochlea. Alignment refers to the to the mechanical axis passing medial to the changing relationship of all the bones of the center of the knee. lower extremity and might best be considered as Two commonly measured angles are the the relationship of the patellofemoral joint to mechanical tibiofemoral angle (center of the body. Mechanical alignment is the sum total femoral head to center of knee to center of talus) of the bony architecture of the entire lower and the anatomical tibiofemoral angle (line extremity from sacrum (center of gravity) to the down center of femoral shaft and line down cen- foot (ground). The position and orientation of ter of tibial shaft). The mechanical tibiofemoral patellofemoral joint to the weight-bearing line angle is the angle between the mechanical axis of determines the direction and magnitude of the femur and the tibia. An angle of 1.2° ±2° is forces that will cross the patellofemoral joint. considered normal (i.e., the limb mechanical The relationship of the patellofemoral joint to axis falls just medial to the center of the knee the body must be defined in all three planes joint).6,7,18,34 The anatomical tibiofemoral angle

Table 11.1. Classification of patellar malalignment Frontal plane Sagittal plane Horizontal Plane Internal rotation External rotation Flexion Extension Medial tilt Lateral tilt (spun) (spun) High Q-angle Low Q-angle Alta Baja Medial shift Lateral shift (translation) (translation) Ch11.qxd 10/07/05 7:20 PM Page 188

188 Etiopathogenic Bases and Therapeutic Implications

Table 11.2. Classification of skeletal malalignment Frontal plane Sagittal plane Horizontal plane Location Location Location Varus Femur Prominent trochlea Femur Inward-pointing Femur (internal torsion) Tibia knee Ligaments Tibia (external torsion) Subtalar joint complex (hyperpronation) Valgus Femur Shallow trochlea Femur Outward-pointing Femur (external torsion) Tibia knee Ligaments Tibia (internal torsion) Subtalar joint complex Aplasic tuberosity Tibia Increased TT-TG Tibia > 20 mm Decreased TT-TG

is the angle between the femur shaft and tibia Rotational (Horizontal or Transverse) shaft and is usually 5.5° ±2°. Different investi- Plane Alignment gators found no difference between males and Rotational plane alignment can be determined 18,44,46 females in these angles. accurately with the use of axial computed tomography. Common measurements are the torsion of the femur, torsion of the tibia, version or the relationship of the distal femur and proximal tibia, and the relationship between the femur and the tibial tuberosity (TT-TG). Bone Torsion Femoral torsion is defined as the angle formed between the axis of the femoral neck and distal femur and is measured in degrees. To assess femoral torsion with CT scan a line from the center point of the femoral head to the center point of the base of the femoral neck is created. This second point is more easily selected by locating the center of the femoral shaft at the level of the base of the neck where the shaft becomes round. Based on the classic tabletop method, the condylar axis is defined as the line between the two most posterior aspects of the femoral condyles. Alternatively a line connecting the epicondyles can be used. Then, the angle formed by the intersection of these two tangents is measured (Figure 11.3). For assessment of tibial torsion a line is drawn across the center of the tibial plateau. As this line is not easy to locate, some authors use the tangent formed by the posterior cortical margin of the tibial plateau. The femoral epicondylar axis might also be selected as it is easier to locate and would appear to be valid because it is the relationship of the knee joint axis to the ankle joint axis that is of concern. Next a line connect- Figure 11.2. Whole limb standing radiograph with mechanical axis ing the center point of the medial malleolus with added showing varus. Ch11.qxd 10/07/05 7:20 PM Page 189

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Figure 11.3. CT rotational study shows 43° of femoral anteversion. Line 1 represents the proximal femoral axis; line 2 is the distal femoral axis (tangent to the posterior condyles).

the center point of the lateral malleolus is pro- condyles and 7° measuring off the epicondylar duced. The angle formed by the intersection of axis (SD 8°). His values generally agree with those these two lines is measured to determine the tib- reviewed in the literature that he tabulated. There ial torsion (Figure 11.4). was no significant difference between males and Strecker et al.39,40 reported the largest series of females. Conversely, lateral tibial torsion aver- torsion determinations in normal individuals aged 24° with a significant difference between using CT scan. The authors measured torsion in males and females at 21° (SD 5°) versus 27° (SD 505 femurs and 504 tibia and found femoral 11°). Furthermore, even greater differences were anteversion of 24.1° ± 17.4° and external tibial noted in the outward foot rotation −5° vs. 11°), torsion of 34.85° ± 17.4°. No correlation to sex which must reflect increases in subtalar position, could be established. Yoshioka45 made direct although this was not mentioned in their paper. skeletal measurements of femur and tibia and These gender differences would explain the found femoral anteversion to average 13° meas- higher incidence of patellofemoral disease in uring off the tangent of the distal femoral females as well as the higher incidence of ACL tears in female athletes. Although this hypothesis is attractive, his findings have not been corroborated by other authors.35,36

TT-TG (Tibial Tuberosity–Trochlear Groove) The relationship of the position of the tibial tuberosity to the trochlear groove will determine the lateralization force acting on the patella through quadriceps contraction. This relationship can be evaluated and quantified by the measurement of the TT-TG. The TT-TG is the distance measured in mm between two perpendiculars to the bicondylar axis.1 One per- pendicular passes through the center of the tib- Figure 11.4. CT rotational study shows 55° of external tibial torsion. Line 1 represents the proximal axis (tangent to the posterior femoral ial tuberosity and the other through the center condyles); line 4 is the distal axis (line connecting most prominent points of the trochlear groove. The measurements are of the medial and lateral malleolus). taken by superposing two CT scan cuts, one cut Ch11.qxd 10/07/05 7:20 PM Page 190

190 Etiopathogenic Bases and Therapeutic Implications

Figure 11.5. CT scan shows measurement of the distance TT-TG.

at the level of the proximal third of the trochlear groove and the other at the superior part of the tibial tuberosity (Figure 11.5). A TT-TG distance of less than 20 mm is considered Figure 11.6. True lateral view shows trochlear dysplasia. The trochlear normal.14 line crosses the contour of the condyles (crossing sign) and a trochlear boss or prominence is present. Sagittal Plane Alignment In the sagittal plane the osseous factors to be evaluated include the trochlea, the tibial tuberosity, Outerbridge. Dejour’s third criterion is the the patellar height, flexion, and length of the actual distance of the floor of the trochlea below radius of curvature for the trochlea. the femoral condyles measured at a point in the Femoral trochlear dysplasia is an abnormality proximal trochlea. In controls this measured 7.8 of the shape and depth of the trochlear groove mm while in patients with objective patellar mainly at its cranial part and has been associated instability it measured 2.3 mm. with patellar instability and anterior knee pain. The shape of the tibial tuberosity is best seen Brattström in 19642 studied trochlear geometry on the lateral radiograph and a hypoplasic tibial in recurrent dislocation of the patella and con- tuberosity may be identified. The prominence of cluded that a shallow femoral groove (i.e., the tibial tuberosity will alter the angle of patel- femoral dysplasia) was the most common cause. lar flexion and consequently change compres- Trochlear dysplasia can be diagnosed by using a sive forces and contact areas in a manner not yet true lateral conventional radiograph of the quantified but speculated as contributing to knee16,32 (Figure 11.6). chondromalacia and pain. Dejour suggested three criteria to diagnose trochlear dysplasia on the lateral view radiograph: the crossing sign, the trochlear boss or Rotational Malalignment and prominence, and the depth of the trochlea. The Contact Pressures in the crossing sign is present when the line representing the floor of the trochlea as it moves proxi- Patellofemoral Joint mally crosses the outline of the lateral femoral Fixed rotation of either the femur or tibia has condyle.8,9 Dejour’s second criterion occurs been shown to have a significant influence on when the proximal extent of the trochlear floor the patellofemoral joint contact areas and pres- extends anterior to the anterior femoral cortex. sures. Lee et al.27,28,29 investigated the effects of A prominence or boss of greater than 3 mm is rotational deformities of the lower extremity on considered as a type of trochlear dysplasia.8,9 patellofemoral contact pressures in a cadaver This may be a variant of the ridge described by model. They simulated various types of rotational Ch11.qxd 10/07/05 7:20 PM Page 191

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deformities of the femur by internally and externally rotated the cadaver knees about the axis 40 30 representing the distal third of the femur. They 20 found that 30 degrees of both internal and 10 30˚ 15˚ external rotation of the femur in their cadaver 0 − 15˚ knee model created a significantly greater peak Pressure 10 −20 30˚ contact pressure on the contralateral facet of −

Percent Change in 30 the patella. External rotational deformities Internal External of the femur were associated with greater peak contact forces on the medial facet of the patella, Torsion while internal rotational deformities were asso- Figure 11.7. Lateral facet pressure change with femoral rotational ciated with higher peak contact pressures on the osteotomy. lateral facet of the patella. A study performed in our institution by Kijowski et al.25 on specimens including the femoral head and foot confirmed Lee’s observa- The results of this study show that variations in tions (Figure 11.7). When the distal femur was femoral torsion (anteversion-retroversion) internally rotated about an osteotomy which caused alterations in the patterns of force trans- increased femoral anteversion there was mission across the patellofemoral joint and in increased contact pressure on the lateral aspect of the strain present in the medial patellofemoral the patellofemoral joint and decreased contact ligament. The increased strain present in the pressure on the medial aspect of the joint. When medial patellofemoral ligament during quadri- femoral torsion was decreased by external rota- ceps activity in individuals with an internally tion osteotomy, there was increased contact pres- rotated femur may first result in pain over the sure on the medial side and decreased contact medial aspect of the knee joint. The medial pressure on the lateral side of the patellofemoral patellofemoral ligament may fail as a result of joint. this increase in strain, leading to instability of the patellofemoral joint. Hefzy et al.17 used a cadaveric model to Rotational Malalignment and Medial study the effects of tibial rotation on the patellofemoral contact pressures and areas. The Patellofemoral Ligament Strain authors found that internal tibial rotation Our study also found that internal rotation increases medial patellofemoral contact areas osteotomy of the femur of 30° results in a signif- while external tibial rotation increases lateral icant increase in the strain in all areas of the patellofemoral contact areas at all flexion angles. medial patellofemoral ligament (Figure 11.8). Lee et al.28,29 corroborated their findings and they

14 Change in Internal Torsion 12 Њ Њ Њ 10 0 15 30 8 6 length 4 MPF ligament 2 Percent Change in 0 30Њ 60Њ 90Њ Knee Flexion Angle

Figure 11.8. Change in length of the medial patellofemoral ligament with increased femoral torsion. Ch11.qxd 10/07/05 7:20 PM Page 192

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also determined the strain in the peripatellar directed vector is resisted by the soft tissue retinaculum at different tibial rotations. They (both the medial and the lateral patellofemoral showed that with increased knee flexion, once ligaments) and by the depth and shape of the the patella is engaged in the trochlea the func- trochlea. With a more dysplastic trochlea the lig- tion of the peripatellar retinaculum is minimal ament stress is increased and with a more nor- and less affected by tibial rotation. mal trochlea the trochlear stress is increased. The foot progression angle (FPA) is generally Effect of Rotational Malalignment defined as the angle between the long axis of the on Patellofemoral Joint Position foot and the direction of body progression and varies from 10° to 20°.31 It has been shown that in Space despite congenital or acquired (after fracture) Maximum gait efficiency with minimal stress is torsional deformities in the lower limb bones, affected by normal limb alignment. Any devia- the FPA remains similar.21,37,42 It is hypothesized tion from normal limb alignment in any plane that the hip musculature plays a role in accom- may also give the same conditions as twisting of modating these deformities during gait. For the knee. These include femoral anteversion or example, in the presence of an internal femoral retroversion, excess internal or external tibial or external tibial rotational deformity with a torsion, genu valgum or varus, hyperpronation, normal FPA, the knee joint axis rotates inward Achilles contracture, and so on. and a side force vector is produced, acting on Twisting of the knee away from the limb the patella so that both the strain on the medial mechanical axis (inward or outward) will change patellofemoral ligament and the compression the direction and magnitude of the patello- on the lateral facet are increased. The opposite femoral compression force and will also add a situation is present with opposite deformities side-directed vector to the patella. This side- (see Figures 11.9 to 11.12).

Figure 11.10. Drawing shows 20° excess tibial external torsion. With Figure 11.9. Drawing shows 20° excess femoral anteversion. With the the foot forward the knee joint points inward, but the hip is also exces- foot forward, the knee joint points inward. sively internally rotated. Ch11.qxd 10/07/05 7:20 PM Page 193

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Figure 11.11. Combined excess external tibial torsion (20°) and excess Figure 11.12. Combined 20° excess external tibial torsion and 20°excess femoral anteversion (20°) with the foot forward. The inward pointing of femoral anteversion. With the knee joint pointing forward the foot points the knee is the sum of the increase in femoral anteversion plus the excess outward and the hip is in a position of abductor weakness. of external tibial torsion. The hip in this position gains abduction leverage.

Treatment important to establish a cause and effect. If a Treatments are best based on an accurate diag- primary abnormality is identified, the treat- nosis and analysis of the above predisposing fac- ment should be directed to correcting this tors (Table 11.3). However, we remain limited abnormality. Any soft tissue or intra-articular by the inability to quantify all of the contribut- procedure is destined to failure if this causality ing factors. In the history of the treatment of the has not been determined. In the vast majority anterior knee pain, efforts have been made to try of cases a combination of predisposing factors to correlate one predisposing factor or one exists. James22 in 1978 described a “miserable cause as responsible for the pathogenesis of the malalignment syndrome,” a combination of anterior knee pain. Likewise different authors femoral anteversion, squinting patellae, genu have proposed different operations to treat varum, patella alta, increased Q-angle, external patellofemoral pain in a standardized fashion. tibial rotation, tibia varum, and compensatory This approach has led to a high incidence of feet pronation. A single common surgical proce- failure in patellofemoral surgery and a bad dure such as lateral release or tibial tubercle reputation. transfer is not likely to cure anterior knee pain Abnormal patellofemoral joint mechanics can in this setting. It is essential to try and detect be the result of many different abnormalities of all of the bony and soft tissue factors that exist, the alignment. Limb geometry, length, body but when multiple contributors are present the weight, and muscle forces combine to generate relative contribution of each is not yet quantifi- the forces that are to be transmitted through the able. In a case with only one variable believed joint. In the analysis of the pathogenesis it is to be responsible for the pathogenesis, that Ch11.qxd 10/07/05 7:20 PM Page 194

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Table 11.3. Correction of skeletal malalignment associated with patellofemoral pathology Deformity Procedure Frontal Plane Genu valgum Femoral osteotomy (supracondylar) Genu varum Tibial osteotomy (infratuberosity) Sagittal Plane Prominent trochlea Trochleoplasty Shallow trochlea Lateral condyle osteotomy Patella alta Distal tubercle transfer Aplasic tuberosity Maquet osteotomy (maintain normal Q-angle) Horizontal Plane Increased femoral anteversion (>25°) Proximal femoral external rotation osteotomy (intertrochanteric) Tibial external torsion (>40°) Proximal tibial internal rotation (infratuberosity) Increased AG-TG(>20 mm) Tibial tubercle medialization Decreased TT-TG Lateral tibial tubercle transfer Combined Deformities Valgus + femoral anteversion Distal femoral varus external rotation osteotomy Varus + femoral anteversion Distal femoral valgus external rotation osteotomy Tibial torsion + increased TT-TG Proximal tibial osteotomy (supratuberosity) Femoral anteversion + tibial torsion Proximal femoral external rotation osteotomy + proximal tibial internal (“miserable malalignment”) rotation osteotomy

variable when possible is corrected. For the these patients presenting with severe instability cases with multiple abnormalities (i.e., femoral and chondropathy often have an underlying anteversion, tibial torsion, genu valgum, and skeletal malalignment that has gone unrecog- patellar subluxation), our approach is either to nized. In such cases it is clear to us that a suc- correct the deformity that is most abnormal or cessful corrective osteotomy performed earlier to correct the factor that we believe contributes in the evolution of the disease would not have most to the symptoms. Multiplane osteotomy is been too aggressive. In some cases with defor- useful when bone geometry is abnormal. mities in two bones, we opt to operate on the It is important to recognize that with a more altered bone first and wait for the evolu- mechanical overload the most prudent treat- tion instead of correcting both bones in the ment should be a reduction of loading condi- same procedure. It is not unusual that the tions by activity restriction or modification, patient experiences some improvement after weight loss, and flexibility and strength training. recovering from the first operation and asks for It might seem too aggressive in some cases to the second bone to be corrected or alternatively perform a femoral or tibial osteotomy to treat considers the improvement sufficient to defer anterior knee pain; however, it has to be under- other procedures. As Brattström2 stated in 1964, stood that the patellofemoral pain is often the “Osteotomy is a big operation.” expression of a complex problem of skeletal geometry. We have seen patients that experi- Level of the Osteotomy enced not only an improvement of the pain after With excessive external torsion of the tibia and a corrective femoral osteotomy, but also the foot moving in the line of a normal foot pro- improvement in the gait pattern, disappearance gression angle, the patella is pulled laterally in the of compensatory foot pronation and bunions, trochlear groove, thus increasing the displace- disappearance of muscle tightness in the thigh ment or subluxation force and the lateral articu- and calf, and even improvement in the posture lar compression force, while internal torsion of and lumbar pain (Figure 11.13). the tibia moves the patella medially within the It has not been uncommon that the asympto- femoral sulcus. If the TT-TG angle is normal the matic knee becomes symptomatic by compari- derotational osteotomy should be performed son to the improved side after correction of below the tibial tubercle (Figure 11.14). deformity. Some patients come to us after five or An osteotomy above the tibial tubercle will six unsuccessful procedures around the patella; change this normal relationship, leading to a Ch11.qxd 10/07/05 7:20 PM Page 195

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Figure 11.13. (a) Picture shows a patient with excess femoral anteversion. On the left side a proximal intertrochanteric femoral derotational osteotomy was performed; the right lower extremity had no surgery. Observe the difference between right and left in the alignment of the extremity. On the right the patella points inward, the calf muscles are more prominent given a pseudovarus appearance, and the foot is more pronated. (b) Postoperative x-rays after proximal femur derotational osteotomy.

reduction in the normal lateral vector with sub- Clinical Experience sequent overload of the medial compartment Cooke et al.5 operated on 9 knees in seven and the addition of an external rotation vector patients with inwardly pointing knees and to the tibial femoral joint. Kelman24 found that a patellofemoral complaints. The authors found medial transfer of the tibial tubercle in a knee this group of patients to have a combined with normal TT-TG did not pull the patella abnormal varus and external torsion of the tibia. medially as much as it may pull the tibia into The operation performed was derotation valgus external rotation. Maquet osteotomy with associated lateral On the femoral side the goal is to create a nor- release. After a three-year follow-up period the mal skeletal geometry. With an excessive increase outcome assessments were excellent for all the in femoral anteversion we prefer to perform rota- cases. tional osteotomy at the intertrochanteric femur Meister and James33 reported on 8 knees in 7 to reduce the sudden change in direction the patients with severe rotational malalignment of quadriceps muscle must make when the the lower extremities associated with debilitating osteotomy is located supratrochlear. If two planes anterior knee pain. The rotational deformity con- need to be corrected, the restoration of a normal sisted of mild femoral anteversion, severe exter- tibiofemoral angle usually requires that nal tibial torsion, and mild tibia vara and pes osteotomy be performed at the distal femur planovalgus. Internal rotation tibial osteotomy (Figures 11.15). We have noted any difference in was performed proximal to the tibial tubercle patients undergoing rotation osteotomy at the with an average correction of 19.7°. At 10 years proximal, mid-, or distal femur. average follow-up all but one patient obtained a Ch11.qxd 10/07/05 7:20 PM Page 196

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Figure 11.14. (a) Patient with excess tibial external torsion (55˚) and normal TT-TG; the foot points outward and the patella points to the front. (b) A proximal tibial internal rotation osteotomy is performed below the tibial tubercle.

subjective good or excellent result while function- subluxation secondary to lateral tibial torsion. At ally all of them had a good or excellent result. 4.3 years follow-up the results were good or excel- Server et al.38 performed 35 tibial rotational lent in 88.5% of the patients and all the patients osteotomies in 25 patients with patellofemoral but two were satisfied with the procedure. Ch11.qxd 10/07/05 7:20 PM Page 197

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Delgado et al.10 treated operatively 9 patients with 13 affected extremities with patellofemoral pathology related to torsional malalignment. The procedures performed were femoral external rotation osteotomy, tibial internal rotation osteotomy, or both. No additional soft tissue procedure that would alter patellar tracking was carried out. At 2.6 years average follow-up all the patients had an improvement in gait pattern and extremity appearance, and a marked decrease in knee pain. In a recent publication Bruce and Stevens3 reviewed the results of correction of miserable malalignment syndrome in 14 patients with 27 limbs. The patients presented significant patellofemoral pain in association with increased femoral anteversion and tibia external rotation. Ipsilateral femoral external rotational osteotomy and tibia internal rotation osteotomy were performed in all the cases. At an average 5.2 years Figure 11.14. (continued) (c) K-wires show a 30˚ correction. A blade plate is used for fixation.

Figure 11.15. (a) Preoperative axial view of a 28-year-old female with history of pain and instability shows collapse of the lateral patellofemoral joint. The patient had valgus and increased femoral anteversion (43°) (b) AP postoperative x-rays after distal femoral varus and external rotation osteotomy. (c) Axial view taken 5 years postoperative shows widening of the lateral patellofemoral space. Ch11.qxd 10/07/05 7:20 PM Page 198

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follow-up, all of the patients reported full satis- patellofemoral osteoarthritis. Arthritis Rheum 2004; 50: faction with their surgery and outcomes. 2184–2190. 5. Cooke, TD, N Price, B Fisher, and D Hedden. The Our Experience inwardly pointing knee: An unrecognized problem of external rotational malalignment. Clin Orthop 1990; We have recently evaluated the clinical results of 260: 56–60. 54 intertrochanteric femoral derotational osteo- 6. Cooke, TD, J Li, and RA Scudamore. Radiographic tomies in 41 patients performed in our institu- assessment of bony contributions to knee deformity. Ortho Clin. North Am 1994; 25: 387–393. tion from 1998 to 2001. The average time of 7. Chao, EY, EV Neluheni, RW Hsu, and D Paley. onset of patellofemoral symptoms was 6.2 years. Biomechanics of malalignment. Ortho Clin North Am All the patients were females with an average age 1994; 25: 379–386. of 28 years (14–54). Osteotomies were indicated 8. Dejour, H, G Walch, P Neyret, and P Adeleine. La dys- plasie de la trochlee femorale. Rev Chir Orthop to correct increased femoral anteversion that Reparatrice Appar Mot 1990; 76: 45–54. was identified as the primary anatomic abnor- 9. Dejour, H, G Walch, L Nove-Josserand, and C Guier. mality. CT rotational studies were available for Factors of patellar instability: An anatomic radi- all the patients and the average preoperative ographic study. Knee Surg Sports Traumatol Arthrosc anteversion was 34.9° (18–54°). Patients were 1994; 2:19–26. 10. Delgado, ED, PL Schoenecker, MM Rich, and AM evaluated by means of Lysholm scale and Capelli. Treatment of severe torsional malalignment Tegner activity level, and were asked if they syndrome. J Pediatr Orthop 1996; 16: 484–488. would have the procedure again. At 7.8 years 11. Eckhoff, DG, AW Brown, RF Kilcoyne, and ER Stamm. (3–16) follow-up, 87% of the patients obtained a Knee version associated with anterior knee pain. Clin Orthop 1997; 339: 152–155. good or excellent result. All the patients but two 12. Elahi, S, S Cahue, DT Felson, L Engelman, and L Sharma. would have surgery again. The association between varus-valgus alignment and patellofemoral osteoarthritis. Arthritis Rheum 2000; 43: Conclusions 1874–1880. ● Bony architecture dictates where the force 13. Fujikawa, K, BB Seedhom, and V Wright. Biomechanics of the patello-femoral joint: Part II. A study of the effect vectors acting on the patella will be directed. of simulated femoro-tibial varus deformity on the con- ● Abnormal skeletal alignment may increase the gruity of the patello-femoral compartment and move- displacement forces acting on both the ligament of the patella. Engineering in Medicine 1983; 12: ments and articular surface of the patella, 13–21. causing either ligament failure with subse- 14. Goutallier, D, J Bernageau, and B Lecudonnec. Mesure de l’écart tubérosité tibiale antérieure-gorge de la quent instability or cartilage overload with trochlée (TA-GT). Rev Chir Orthop, 1978; 64: 423–428. subsequent arthrosis. 15. Greene, CG, TB Edwards, MR Wade, and EW Carson. ● Treatment depends on what is the primary Reliability of the quadriceps angle measurement. Am J pathology; with large displacement force the Knee Surg 2001; 14: 97–103. 16. Grelsamer, RP, and JL Tedder. The lateral trochlear best treatment might be osteotomy of long sign: Femoral trochlear dysplasia as seen on a lateral bones. view roentgenograph. Clin Orthop 1992; 281: 159–162. ● Procedures intended to repair soft tissues often 17. Hefzy, MS, WT Jackson, SR Saddemi, and YF Hsieh. fail if the forces directed by the skeletal malalign- Effects of tibial rotations on patellar tracking and patello- ment are unrecognized or not addressed. femoral contact areas. J Biomed Eng 1992; 14: 329–343. 18. Hsu, RW, S Himeno, MB Coventry, and EY Chao. ● Osteotomy for patellofemoral arthrosis may Normal axial alignment of the lower extremity and be as logical as HTO for varus gonarthrosis. load-bearing distribution at the knee. Clin Ortho 1990; 255: 215–227. 19. Hvid, I, LI Andersen, and H Schmidt. Chondromalacia References patellae: The relation to abnormal patellofemoral joint 1. Bernageau, J, and D Goutallier. La mesure de la distance mechanics. Acta Orthop Scand 1981; 52: 661–666. TA-GT. In Le scanner ostéo-articulation. Le genou. 20. Insall, J, KA Falvo, and DW Wise. Chondromalacia Paris: Vigot, 1991, pp. 132–144. patellae: A prospective study. J Bone Joint Surg Am 2. Brattström, H. Shape of the intercondylar groove nor- 1976; 58-A: 1–8. mally and in recurrent dislocation of patella: A clinical 21. Jaarsma, RL, BF Ongkiehong, C Gruneberg, N and x-ray anatomical investigation. Acta Orthop Scan Verdonschot, J Duysens, and A van Kampen. Supplementum 1964; 68. Compensation for rotational malalignment after 3. Bruce, WD, and PM Stevens. Surgical correction of mis- intramedullary nailing for femoral shaft fractures: An erable malalignment syndrome. J Pediatr Orthop 2004; analysis by plantar pressure measurements during gait. 24: 392–396. Injury 2004; 35: 1270–1278. 4. Cahue, S, D Dunlop, K Hayes, J Song, L Torres, and L 22. James, S, BT Bates, and LR Ostering. Injuries to run- Sharma. Varus-valgus alignment in the progression of ners. Am J Sports Med 1978; 6: 40–50. Ch11.qxd 10/07/05 7:20 PM Page 199

Skeletal Malalignment and Anterior Knee Pain 199

23. Janssen, G. Increased medial torsion of the knee joint 33. Meister, K, and SL James. Proximal tibial derotation producing chondromalacia patella. In Trickey, E, and P osteotomy for anterior knee pain in the miserably Hertel, eds., Surgery and Arthroscopy of the Knee, 2nd malaligned extremity. Am J Orthop 1995; 24: 149–155. Congress. Berlin: Springer-Verlag, 1986, pp. 263–267. 34. Moreland, JR, LW Bassett, and GJ Hanker. Radiographic 24. Kelman, GJ, L Focht, JD Krakauer et al. A cadaveric analysis of the axial alignment of the lower extremity. study of patellofemoral kinematics using a biomechan- J Bone Joint Surg 1987; 69-A: 745–749. ical testing ring and gait laboratory motion analysis. 35. Reikeras, O, and A Hoiseth. Torsion of the leg deter- Orthop Trans 1989; 13: 248–249. mined by computed tomography. Acta Orthop Scand 25. Kijowski, R, D Plagens, SJ Shaeh, and RT Teitge. The 1989; June, 60(3): 330–333. effects of rotational deformities of the femur on contact 36. Sayli, U, S Bolukbasi, OS Atik, and S Gundogdu. pressure and contact area in the patellofemoral joint and Determination of tibial torsion by computed tomogra- on strain in the medial patellofemoral ligament. phy. J Foot Ankle Surg 1994; Mar.–Apr., 33(2): 144–147. Presented at the annual meeting International Patello- 37. Seber, S, B Hazer, N Kose, E Gokturk, I Gunal, and A femoral Study Group, Napa Valley, San Francisco, Turgut. Rotational profile of the lower extremity and September 1999. foot progression angle: Computerized tomographic 26. Lauren, CA, R Dussault, and HP Levesque. The tangential examination of 50 male adults. Arch Orthop Trauma x-ray investigation of the patellofemoral joint: X-ray Surg 2000; 120: 255–258. technique, diagnostic criteria and their interpretation. 38. Server, F, RC Miralles, E Garcia, and JM Soler. Medial Clin Orthop 1979; 144: 16–26. rotational tibial osteotomy for patellar instability second- 27. Lee, TQ, SH Anzel, KA Bennett, D Pang, and WC Kim. ary to lateral tibial torsion. Int Orthop 1996; 20: 153–158. The influence of fixed rotational deformities of the 39. Strecker, W, M Franzreb, T Pfeiffer, S Pokar, femur on the patellofemoral contact pressures in M Wikstrom, and L Kinzl. Computerized tomography human cadaver knees. Clin Orthop 1994; 302: 69–74. measurement of torsion angle of the lower extremities. 28. Lee, TQ, BY Yang, MD Sandusky, and PJ McMahon. Unfallchirug 1994; 97: 609. The effects of tibial rotation on the patellofemoral 40. Strecker, W, P Keppler, F Gebhard, and L Kinzl. Length joint: Assessment of the changes in in-situ strain in the and torsion of the lower limb. J Bone Joint Surg 1997; peripatellar retinaculum and the patellofemoral con- 79-B: 1019–1023. tact pressures and areas. J Rehabil Res Dev 2001; 38: 41. Takai, S, K Sakakida, F Yamashita, F Suzu, and F Izuta. 463–469. Rotational alignment of the lower limb in osteoarthritis 29. Lee, TQ, G Morris, and RP Csintalan. The influence of of the knee. Int Orthop 1985; 9: 209–215. tibial and femoral rotation on patellofemoral contact 42. Tornetta, P, G Ritz, and A Kantor. Femoral torsion area and pressure. J Orthop Sports Phys Ther 2003; 33: after interlocked nailing of unstable femoral fractures. 686–693. J Trauma 1995; 38: 213–219. 30. Lerat, JL, B Moyen et al. Morphological types of the 43. Turner, MS. The association between tibial torsion and lower limbs in femoro-patellar disequilibrium: Analysis knee joint pathology. Clin Orthop 1994; 302: 47–51. in 3 planes. Acta Orthop Belg 1989; 55: 347–355. 44. Yoshioka, Y, D Siu, and TDV Cooke. The anatomy and 31. Lösel, S, MJ Burgess-Milliron, LJ Micheli, and CJ Edington. functional axes of the femur. J Bone Joint Surg 1987; 69- A simplified technique for determining foot progres- A: 873–880. sion angle in children 4 to 16 years of age. J Pediatr 45. Yoshioka, Y, and TDV Cooke. Femoral anteversion: Orthop 1996; 16: 570–574. Assessment based on function axes. J Orthop Res 1987; 32. Malghem, J, and B Maldague. Depth insufficiency of the 5: 86–91. proximal trochlear groove on lateral radiographs of the 46. Yoshioka, Y, DW Siu, RA Scudamore, and TDV Cooke. knee: Relation to patellar dislocation. Radiology 1989; Tibial anatomy and functional axes. J Ortho Res 1989; 7: 170: 507–510. 132–137.