20 Complicated Case Studies

Introduction

Patellofemoral problems with anterior knee pain (AKP) represent a significant problem for the cli- nician with regard to diagnosis and conservative and operative treatment. Anterior knee pain can be caused by single trauma or may be cumulative.

The patellofemoral joint (PFJ) can be painful during periods of rapid growth in adolescence, after increased repetitive activity of the knee during sports, or just in daily life, like long sitting in a car or walking down the stairs. This means, that each level of activity or all types of use of the knee during various occupations can cause AKP.

Accordingly, the causes of complaints and the underlying pathologies are various. Therefore it seems logical that successful treatment can only be achieved with respect to the specific pathomor- phology. This again presupposes the best possible diagnosis. A consolidated diagnosis is the key of long-term effective and successful therapy.

The two following complicated case studies represent a summation of my clinical experi- ence including thoughts, critical opinions, and accomplishments of colleagues and experts in orthopedic surgery. Special attention has been given to the different possibilities of evaluating the patellofemoral relationship.

For an annual meeting presentation to the International Patellofemoral Study Group we evaluated the clinical histories and courses of 10 patients with the worst histories.

These 10 patients underwent altogether 124 operations to treat patellofemoral problems on one of their knees. We examined 8 females and 2 males with the mean age of 21 years (range 14–41 years) at the time of the first surgical intervention. The average number of operations was 12 (range 7–25). The initial diagnosis was in 5 cases a dislo- cation of the patella, 4 patients suffered from

pain, and 1 patient had a direct contusion. The first surgical procedure was in 8 cases a transpo- sition of the tibial tuberosity (medially, proxi- mally, advancement or in combination), and all patients had one or several releases of the lateral retinaculum (n = 2–6). The evaluation showed that 5 patients had a proximal dysplastic trochlea but a distal correction. Seven patients suffered from an unequivocal medial subluxation of the patella following the lateral release. The last sur- gical procedure was in 4 cases a Re-Elmslie, 9 had a secondary reconstruction of the lateral retinac- ulum, 5 an elevation of a low lateral condyle, and 5 a resection of a hypertrophic synovial plica.

All patients with the initial diagnosis of patella dislocation had also a proximal dysplasic trochlea (low lateral condyle or short trochlea).

Therefore the procedures on the tibial tuberos- ity were in 50% of cases probably not necessary.

The necessity to perform a Re-Elmslie confirms this statement. The lateral retinaculum release (LRR) could not even help one patient as a sin- gle surgical procedure.

The medial subluxation with instability was a major problem in our chronic cases. Chondral damage was never the initial problem that started the series of operations. In conclusion, we found in this retrospective analysis no treat- ment strategies or clear concepts focusing on the underlying pathology. This explains the cat- astrophic long-term outcomes and the chronic complaints of the patients.

Two of these 10 patients are presented in the following as complicated case studies. The major problems and mistakes of diagnosis and treatment are summarized, and the missing or insufficient diagnostic investigations described and explained. Treatment concepts offer possi- bilities to escape the presented problems.

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20

Complicated Case Studies

Roland M. Biedert

Case Study 1

History

A 19-year-old female patient suffered from unspecific bilateral AKP. The first operation was performed in the age of 19 years and consisted of an enlarged Roux procedure (medial transfer of the patellar tendon, release of lateral retinac- ulum, and plication of the medial retinaculum).

At the age of 43 years she had a total of 24 operations on the same right knee. In addition to numerous arthroscopic revisions, a LRR was redone six times, different osteotomies (valgisa- tion, flexion, varisation) performed, and differ- ent treatments on the tibial tuberosity (Roux, Bandi, Elmslie) added. The major problems included at the time of the first presentation in our clinic chronic pain, effusion and swelling, loss of strength, inability to perform almost all types of sport, and reduction in daily life.

Comments

Surgical treatment of unspecific AKP in the young female patient is a controversial problem.

The excessively high number of contradictory operative interventions documents the inaccu- rate existing therapeutic concepts in resolving this pain problem surgically.

Course of Action

The physical examination of this patient showed tenderness and pain on palpation on the proximal lateral aspect of the patella, the medial facet of the patella and the medial femoral condyle, the tibial tuberosity, and the patellar tendon. A mild chronic effusion could be documented.

The range of motion was unlimited. The patella apprehension test was positive especially to the medial side but also laterally with pain and crepi- tation. The patella was locking during flexion and extension movements between 20 ° and 40° of flexion. The patella tendon was stuck to the head of the tibia. The Q-angle (measured in extension) was 8 ° on the right side (Figure 20.1A) and 15° on the left side (Figure 20.1B). One leg standing in flexion, like going downstairs, was painful and created continued limping.

Figure 20.1. Excessive medialization of the patella following transposition of the tibial tubercle and repeated release of the lateral retinaculum (a).

Situation on the nonoperated left knee (b).

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Figure 20.2. Axial CT-scans in extension (a). Right knee: Overmedialization of the patella with subluxation and destruction of the patellofemoral joint.

Left knee: Normal patella position in the trochlea despite high Q-angle value. Schematic diagram of the medial degenerative changes (‡) due to mal- position (b).

Diagnostic Examinations

The most important diagnostic studies in these types of patellofemoral complaints are the physical examination and the axial computed tomography (CT) evaluation. The medial instability and the painful medial apprehension test document the significant medial subluxation of the patella.

Performing axial CT-scans in extension with and without quadriceps contraction and in 30 ° of knee flexion is the best imaging procedure to evaluate the patellofemoral relationship near extension

(Figures 20.2A, 20.2B);

3D-CT-scans are also available and even improve the diagnostic value of this type of imaging (Figures 20.3A, 20.3B).

Treatment Concepts

●

What is the reason for the medial subluxation of the patella?

●

Can this cause chronic pain, effusion, and

locking?

●

Which other structures are involved in the problem?

●

What kind of procedure is necessary and how do we make the decision?

After 24 operations it is not possible to regain a good result. The goal must be to eliminate the medial subluxation and to improve the passive stability of the patella in the femoral groove.

The clinical examination showed that the lateral retinaculum is no longer a functional passive structure. The increased mobility of the patella (more than 3 quadrants) to the medial side doc- uments the secondary instability.

This is also visible on the axial CT-scans. The medial sub- luxation caused the overuse with degenerative changes on the medial patellofemoral joint.

Strengthening of the vastus medialis obliquus muscle as a dynamic stabilizer of the patella cannot be successful as this increases the medial subluxation.

The first step of treatment must include the recentering of the patella in the trochlea in combination with increased ligament stabiliza-

tion. This can only be achieved by a Re-Elmslie procedure and a secondary reconstruction of the lateral retinaculum using either the local scar tissue or a tendon graft.

To decide how much we have to lateralize again the tibial tuberosity we can use the measurement and alignment of the nonoperated knee (if avail- able). After the bony realignment has been per- formed, the lateral retinaculum is reconstructed with respect to a normal patella mobility of 1 to 2 quadrants.

Discussion

Twenty-four operations on the right knee could not resolve the initial problem of unspecific pain. The local situation got worse and worse with each surgical procedure. Regarding the left knee, which was initially also painful but was never operated, one must conclude that probably no surgical intervention was ever necessary.

Unspecific AKP without documented pathologi- cal patellofemoral relationship is primarily always a matter of conservative treatment. This consists of controlled adaptation of the individual

Figure 20.3. 3D-CT ap-view with medial patellar subluxation (right side) (a). View from proximal to distal (right side) (b).

load acceptance. Medications (analgesics, nons- teroidal anti-inflammatory drugs, intra-articular injections) can be helpful to relieve pain and inflammation. Physical therapy is needed for strengthening, stretching, and mobilization of the different structures. Clear pathological factors such as foot disorders, lateral muscle tightness, increased hip antetorsion, or lower back prob- lems can be treated by adequate conservative therapy. Only a few pathological factors (like dys- plastic femoral condyle, trochlear-bump, plicae syndrome, loose bodies) are indications for surgi- cal treatment.

The presented case study raises two questions:

1. Is an “abnormal” Q-angle an indication for a medialization of the tibial tuberosity?

2. When do we perform an LRR?

The indication for the transposition of the tib- ial tuberosity was in this case a Q-angle of 15 °.

Many authors use a so-called “pathological”

Q-angle (measured in extension) as an indication for medialization.

But the diagnostic relevance of the Q-angle has never been established.

There exists not even a universally accepted method with detailed description of how to meas- ure the Q-angle.

Messier and colleagues

meas- ured the Q-angle using a goniometer and two anatomically defined lines: one line connecting the anterior-superior iliac spine (ASIS) and the mid-point of the patella, and a second line con- necting the mid-point of the patella and the center of the tibial tuberosity in extension. He considered Q-angle values in excess of 16 ° to be significantly associated with patellofemoral pain.

Ford and Post

and Caylor and colleagues

defined the Q-angle in the same way. Q-angle values of 15 ° or less were considered to be normal and angles greater than 20 ° should be considered abnormal.

The question of how values between 16 ° and 19°

should be regarded remained unanswered.

Papagelopoulos and Sim

considered generally Q-angle values greater than 20 ° as abnormal and associated with patellofemoral pain. Caylor and colleagues

measured the Q-angle also in two dif- ferent standing positions. Finally Guzzanti and colleagues

performed the examination of the Q-angle using CT-scans in 15 ° of knee flexion.

They found average values of 19.4 ° in sympto- matic patients and 20.2 ° in the healthy control group.

In conclusion, there exists an immense con- troversy about how to measure the Q-angle and

what are its normal values. Therefore it seems dangerous to draw the conclusion that an

“abnormal” Q-angle is an etiological factor in AKP.

The lateral patellar retinaculum is an impor- tant anatomical structure, which interplays with the intra-articular components and the dynamic structures to ensure patellofemoral stability.

This allows correct function- ing of the joint. The position of the patella, the central pivotal point of the knee extensor mechanism, is thus controlled by the lateral patellar structures.

The resultant pulling force of the quadriceps muscle acts on the tibial tuberosity. Therefore, and due to a frequently present valgus axis about the knee, both a laterally directed force vector and the Q-angle are created.

The patella’s tendency to dislocate laterally is counteracted by the horizontal portion of the vastus medialis obliquus muscle and the geometry of the trochlea, especially the shape of the lateral condyle. This underlines the importance of coronal, sagittal, and horizontal alignment in the lower extremity.

The incision (release) of the lateral retinacu- lum results in biomechanical changes of the position of the patella and its gliding behavior in the trochlea.

Some authors explain the ther- apeutic effect as being due to reduction of the pressure in the patellofemoral joint. These authors attribute the positive results of the LRR to a temporary recovery of the cartilage resulting from a shift of the contact surface area of the patella with consecutive changes of local pres- sure points. Thus, it is assumed that there is no significant reduction in the pressure of the con- tact surfaces in the patellofemoral area but rather a change of the contact side area with highest- pressure forces.

The combination of LRR with medialization of the tibial tuberosity increases the risk of both medial subluxation of the patella and overloading of the medial patellofemoral joint, as described in our case study.

Kolowich and colleagues

found in 55% of their patients continued repetitive episodes of lateral disloca- tion following LRR for patellar dislocation. This problem will also be described in the second case study. Hughston and Deese

reported the increased possibility of medial subluxation in 50% of patients treated with LRR. Teitge

doc- umented recurrent medial subluxations and dis- locations of the patella after LRR using patellofemoral stress x-rays. We found in our

Complicated Case Studies 327

series in 78% disabling medial subluxation of the patella with a severe imbalance of the patellofemoral gliding mechanism following LRR.

Additionally we documented the medial patellar instability following LRR performing quantitative gait analysis.

The gait analysis con- sisted of video recordings, three-dimensional motion analysis, dynamic electromyography, and sampling of the ground reaction forces.

Abnormal medial translation of the patella was observed during unloading of the leg while the knee was bending in preparation for the swing phase.

This is a phase during the gait cycle when the quadriceps muscle is silent and the patella position is guided by the passive struc- tures. These findings weaken the argument of muscle imbalance as a cause for the patellar instability and stresses the importance of well- balanced passive structures. It explains why a muscular rehabilitation program is likely to fail as long as the passive structures allow the insta- bility to occur.

Therefore lengthening of the lateral retinacu- lum is the therapy to choose. The lateral reti- naculum consists of a superficial oblique and deep transverse part (Figure 20.4A).

Lengthening is started incising longitudinally the superficial oblique retinaculum about 5 mm from its attachment to the lateral border of the patella, down to the ligamentum patellae. Then it is separated from the deep transverse retinac- ulum preparing with a knife in the dorsal direc- tion (Figure 20.4B). As much dorsal as possible, then the deep transverse ligament is incised also longitudinally and the synovial layer opened (Figure 20.4C). This releases the increased ten- sion of the lateral structures. The two parts of the lateral retinaculum are sutured together in 90 ° of knee flexion (Figure 20.4D). This makes it impossible that the retinaculum is too tight.

The mobility of the patella should be 1 to 2 quadrants to the medial and the lateral side in full extension, guaranteeing a normal balance of the patella in the trochlea.

Summary

This case outlines the severe complications fol- lowing the medial transposition of the tibial tuberosity in combination with LRR in a patient with unspecific AKP. Secondary instability of the patellar gliding mechanism and degenerative changes with overuse of the medial patellofemoral joint are the major problems creating chronic pain and disability.

Case Study 2

History

This female patient had undergone surgery per- forming an Elmslie procedure at the age of 15 years because of repetitive patellar dislocation.

Nevertheless the dislocations continued and the medialization of the tibial tuberosity was at the end 28 mm. At the age of 42 years she had in total 15 operations including LRR, denervation, and shaving of the patellar cartilage. The major problems consisted of chronic pain on the medial femorotibial and patellofemoral joint, weakness and instability during loaded flexion, and disability in daily living.

Comments

The recurrent subluxation or dislocation in the young patient is a severe problem. Dislocations without primary traumatic etiology indicate an abnormal biomechanical situation. This includes, for example, dysplastic lateral femoral condyle, patella alta, tight lateral structures, or weakness of the vastus medialis obliquus muscle.

Course of Action

The physical examination showed both medial and still lateral subluxation of the patella with painful apprehension tests in both directions.

Severe crepitations were found in the medial patellofemoral joint with locking. The medial femorotibial joint line was painful with positive meniscus signs during rotation. The Q-angle was negative with minus 3 °. The tibial tuberosity was palpated on the medial side of the tibial head. Varus instability and varus axis were increased in one leg standing.

Diagnostic Examinations

Full weight-bearing x-rays documented a severe medial subluxation of the patella and an exces- sive medialization of the tibial tuberosity (Figures 20.5A, 20.5B). Varus axis with advanced osteoarthritis of the medial femorotibial compartment was noted. Axial CT-scans docu- mented overloading of the medial patellofemoral joint with degenerative changes in addition to a flat lateral condyle and a nonexisting trochlear groove (Figure 20.6).

Treatment Concepts

●

How is it possible that the patella lies

extremely on the medial side but still sublux-

ates laterally?

Complicated Case Studies 329

Figure 20.4. Schematic diagram showing the lengthening of the lateral retinaculum (technical note according to R.M. Biedert.) (continued)

Figure 20.4. (continued)

Complicated Case Studies 331

Figure 20.5. Long one-leg standing ap-x-ray with medial subluxation of the patella ( ), varus axis and medialization of the tibial tubercle (fl) (left knee) (a). Negative imaging x-ray showing the degenerative changes on the medial femorotibial joint (‡) and the medialized tibial tubercle (➤) (left knee) (b).

Figure 20.6. Axial CT-scans in extension documenting the medial patella subluxation and the destruction of the medial patellofemoral joint on the left side (·).

●

What is the reason for the medial pain?

●

What kind of surgical treatment is necessary to eliminate the subluxation in both diametric directions?

●

What do we do with the overmedialization of the tibial tuberosity?

●

Has the varus axis a negative influence on the medial patellofemoral and femorotibial joint?

Our treatment of this patient consisted of four major steps:

1. Arthroscopy with partial medial meniscec- tomy and debridement of scar tissues.

2. Re-Elmslie with normal positioning of the tib- ial tuberosity according to the tibial shaft axis (Figures 20.7A, 20.7B).

3. High tibial valgisation osteotomy (new axis of 7 ° valgus) including high fibular osteotomy (Figure 20.8).

4. Elevation of the lateral femoral condyle using a self-locking bone wedge (taken from the

tibia) reconstructing a trochlear groove (Figures 20.9A, 20.9B). In Figure 20.10 you can see the steps to perform a trocheoplasty.

At 6 years follow-up, the result was subjec- tively and objectively positive with generally improved function of the knee joint (Figure 20.11). A new joint line was formed in compari- son to the former situation (Figure 20.6).

Discussion

Twenty-eight millimeters medialization of the tibial tuberosity of twenty-eight millimeters could not eliminate the lateral subluxations of the patella near extension. But this excessive medialization created together with several LRR procedures severe medialization of the patella with degenerative changes of the patellofemoral joint and important weakness of the extensor and decellerator mechanism. The reason why the patella was still laterally subluxating was the low lateral femoral condyle. Therefore, the

Figure 20.7. Intraoperative ap-view: center of the tibial tubercle (·); patella (p); K-wire indicating the normal axis of the tibia (left side) (a). Detached tibial tuberosity showing the amount of medialization before Re-Elmslie (left side) (b).

osseous resistance of a normal lateral condyle was missing and the laterally directed force vec- tor of the quadriceps muscle caused the lateral subluxation of the patella. The vastus medialis obliquus muscle, acting as an antagonist to this force, was not strong enough to pull the patella

medially.

The medialization created at the same time a severe overloading of the medial femorotibial compartment, resulting in destruc- tion of the medial meniscus, osteoarthritis of the joints, and varus deformity.

This case study raises two questions:

Complicated Case Studies 333

Figure 20.8. Sagittal and ap-x-rays after Re-Elmslie, high tibial, and fibular osteotomies.

Figure 20.9. Intraoperative anterolateral view: low lateral condyle (·), lateral osteophytes caused by subluxation ( ), degenerative changes of the medial patellofemoral joint (fl) (a).

(continued)

1. Which diagnostic imaging is necessary in young patients with recurrent patellar dislo- cation?

2. How can we treat recurrent patellar disloca- tion in adolescent or adult patients?

Correct lateral x-rays in 30 ° of knee flexion can be used to document form and depth of the

trochlea.

The crossing sign is a simple and characteristic finding in dysplastic trochlea.

The dysplastic trochlea is in most cases an indication for surgical reconstruction. CT- scans are helpful in these cases for classifica- tion and determination of the type of surgery.

Sasaki and Yagi

and Biedert and Gruhl

demonstrated that the evaluation of the

Figure 20.9. (continued) Intraoperative anterolateral view after elevation of the lateral condyle. Bone wedge (·) (b).

(a) (b) (c) (d)

(g) (f)

(e)

Figure 20.10. Normal depth and length of the trochlea and height of the condyles (a). Dysplastic trochlea with flat lateral condyle (b). Too short trochlea with normal height and depth (c). Incomplete osteotomy of the lateral condyle (dotted line) about 5–7 mm from the cartilage down to the sulcus terminalis (d). The lateral condyle (osteochondral flap) is raised with a chisel (carefully!) and the gap filled with cancellous bone (dotted area) taken from the lateral head of the tibia (e). Dotted line showing the lateral incomplete osteotomy in a too short trochlea (f). Situation after length- ening of a too short trochlea: Lengthening includes 10–15 mm of the lateral femoral shaft (g).

first 30 ° of knee flexion gives the most impor- tant diagnostic information about the patellofemoral congruence. This agrees with Goodfellow’s biomechanical studies demon- strating that the most susceptible position for patella dysfunction is at the beginning of knee flexion.

At this position, the patella normally starts to center itself in the femoral trochlea.

The patella lies in extension more lateral and proximal in the femoral groove and the lateral condyle gives less osseous support to the patella. At this position, the patella must be guided by the normal shaped lateral condyle into the trochlear groove with increased flex- ion. This maneuver is missing in a short trochlea or a patella alta.

Patients presenting a low lateral condyle (crossing sign in x-ray) are therefore susceptible for recurrent patellar dislocation.

These patients need either elevation of the condyle or trochlear deepening plasty when they are out of adolescence.

Different treatment is necessary in young patients with open epiphyseal carti- lage. Only soft tissue reconstruction (imbrica- tion of the medial retinaculum and/or vastus medialis obliquus muscle or shortening/tighten- ing of the medial patellofemoral ligament, lengthening of the lateral retinaculum) can be performed in young patients to avoid early epi- physeal fusion.

Summary

This case outlines unsuccessful treatment per- forming medialization of the tibial tuberosity in recurrent patellar dislocation in patients with dysplastic trochlea. A distal correction is not suf- ficient and adequate to treat a proximal patho- logical situation on the femur. In contrast, it can be dangerous creating secondary pathologies.

The goal of the surgical reconstruction must be the elimination of the real pathology. The pathol- ogy in recurrent patellar dislocations is in most cases a dysplastic trochlea and only a few dislo- cations are really traumatic.

In addition to lat- eral normal x-rays, the axial CT-scans in 0 ° of knee flexion with and without quadriceps muscle contraction are the best imaging modality to demonstrate abnormal patellofemoral relation- ship.

Medialization of the tibial tuberosity always includes the risk of overloading the medial patellofemoral and femorotibial joint.

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