Pediatric Distal Stabilization Procedures

Colleen Wixted

Meghan Price

Daniel W. Green

Shital N. Parikh

INTRODUCTION

Patellar dislocation is a common acute knee injury affecting the pediatric and adolescent populations.¹,² Nonsurgical conservative treatment involving physical therapy and activity modification is usually recommended for first-time traumatic patellar dislocations. Many surgical techniques have been described to address patellar instability, but medial patellofemoral ligament (MPFL) reconstruction and/or distal realignment are among the most common procedures used.³,⁴ This chapter focuses on distal realignment techniques specifically for the skeletally immature.
Tibial tubercle osteotomies, the Roux-Goldthwait procedure, patellar tendon transfer, Nietosvaara technique, combined MPFL and medial patellotibial ligament (MPTL) reconstruction, and the Galeazzi technique are among the various procedures that have been developed to address distal malalignment issues.
Tibial tubercle osteotomies are only indicated in adolescents if the proximal tibial physis is closed or closing.⁵ These techniques are discussed in Section III.
Many variations of the other procedures exist, some of which are no longer regularly performed because of poor reported outcomes.⁶,⁷ Each of these techniques will be discussed—focusing primarily on those that have demonstrated higher success rates.

INDICATIONS

Distal realignment procedures have been indicated for patients who have failed conservative treatment and present with persistent symptoms. Historically, an elevated Q angle, trochlear dysplasia, patella alta, and other radiographic findings were commonly cited as an indication for a pediatric distal realignment.
As seen in Table 29.1, indications for a distal realignment procedure vary by technique and are dependent upon the patient’s clinical and radiographic presentation.
The Roux-Goldthwait procedure is indicated for patients who have failed conservative treatment, are experiencing persistent symptoms, and have an elevated Q angle.⁸,⁹
The patellar tendon transfer is typically used for patients aged 10 years and younger with an abnormal Q angle and heightened femoral sulcus angle in addition to an increased tibial tubercle-trochlear grove (TT-TG) distance.¹⁰,¹¹,¹²
Nietosvaara et al similarly reported a severe Q angle, excessive patella alta, and trochlear dysplasia as indications for a distal realignment procedure.¹³,¹⁴
The Galeazzi technique was used for skeletally immature patients who were ligamentously lax with patella alta and other abnormal clinical findings.⁶,¹⁵,¹⁶,¹⁷
At our institution, we elect to perform a distal realignment procedure in addition to an MPFL reconstruction for patients with an increased TT-TG distance.
When measuring the TT-TG distance in pediatric patients, it is important to use age-related normal values rather than fixed adult parameters.¹⁸ In a study of 608 magnetic resonance imaging (MRI), Dickens et al found the TT-TG distance to be positively correlated with the natural logarithm of age.¹⁹
In the case of a mildly elevated TT-TG distance, we also consider a pediatric distal realignment procedure in the context of additional factors, such as trochlear dysplasia and/or positive J-sign.¹⁰,²⁰,²¹

OVERVIEW OF SURGICAL TECHNIQUES

Roux-Goldthwait Procedure

The Roux-Goldthwait procedure, first described by both Roux and Goldthwait in 1888 and 1895, respectively, was later modified in 1985 to involve a lateral release, plication of the medial retinaculum, and medial transfer of the lateral patellar tendon with and without advancement of the vastus medialis²²,²³,²⁴ (Figure 29.1).

More recently, Marsh et al introduced an addition to better align the extensor mechanism with the femoral shaft.⁸ In this technique modification, the
patellar tendon is split longitudinally, and its lateral half is detached and transferred distally beneath its medial half. The free end is then sutured to periosteum on the medial side of tibia.⁸ With mean longterm follow-up of 6.2 years, Marsh et al reported excellent results in 65%, good in 11%, and fair in 3% of the knees operated on with this modified technique.⁸ Of the patients in this cohort whose strength was evaluated, 80% returned to 90% strength in the operated leg.⁸

TABLE 29.1 Indications by Procedure

Procedure	Study	Study Cohort	Indications (Other Than Patellar Instability)
Roux-Goldthwait	Marsh et al⁸	N = 20 patients (30 knees) Age: 3-18 y, M = 14.2	Elevated Q angle Persistent symptoms: pain/swelling
Roux-Goldthwait	Vähäsarja et al⁹	N = 48 patients (57 knees) Age: 7-16 y, M = 13.4	Radiologic findings (eg, Insall-Salvati index, lateral patellofemoral angle, lateral patellar deviation, lateral patellar tilt, sulcus angle, Q angle) Failed conservative treatment Prolonged duration of symptoms Pathologic lateralization of the patella during arthroscopy
Galeazzi	Grannatt et al⁶	N = 28 patients (34 knees) Age: 4.5-15.8 y, M = 11.1	Skeletally immature Failed conservative treatment
	Letts et al¹⁵	N = 22 patients (26 knees) Age: 8-17 y, M = 14.3	Skeletally immature Patella alta Ligamentous laxity
	Hall et al¹⁶	N = 21 patients (26 knees) Age: 4-30 y, M = 14.5	Persistent symptoms: pain/swelling Radiographic signs (lateral patellar tilt, osteochondral fracture) Clinical signs (eg, patellar facet tenderness, positive apprehension test, patellofemoral crepitus, quadriceps atrophy, subluxation in extension)
	Baker et al¹⁷	N = 42 patients (53 knees) Age: 5-17 y, M = 12	Relative factors of lax patellar mechanism, high-riding patella, genu valgum and recurvatum, low lateral femoral condyle
Nietosvaara	Giordano et al¹⁴	NA	Excessive patella alta Severe Q angle (>15°) Trochlear dysplasia TAGT (distance between anterior tuberosity and the deeper part of the groove) > 1.2 cm Hyperlaxity
Nietosvaara	Nietosvaara et al¹³	N = 62 patients (64 knees) Age: under 16 y	Recurrent patellar dislocation with functional disability
Patellar Tendon Transfer	Nepple and Luhmann¹⁰	NA	Typically 10 y or younger Bony malalignment Abnormal Q angle Increased TT-TG distance Trochlear dysplasia and patella alta (sometimes present)
	Luhmann et al¹¹	N = 23 patients (27 knees) Age: 8.8-18.3 y, M = 14.1	Q angle > 15°
	Garin et al¹²	N = 35 patients (50 knees) Age: 5-15 y, M = 11	Abnormal femoral sulcus angle
Abbreviations: M, mean; NA, not applicable; TT-TG, tibial tubercle-trochlear groove.

Figure 29.1 Roux-Goldthwait procedure.

Although this study and others report improved outcomes,²⁵,²⁶,²⁷,²⁸ there is an increasing body of literature indicating high rates of recurrence, patella infera,²⁹ and other complications following the modified Roux-Goldthwait procedure.⁹,²⁹,³⁰,³¹
A study comparing MPFL reconstruction using adductus magnus transfer to the Roux-Goldthwait procedure reported that patients in the MPFL cohort reported less pain postoperatively.³² While the Kujala and Lysholm scores, recurrence rates, patellofemoral angles, and apprehension test results did not demonstrate significant differences between these two groups, the MPFL group had significantly fewer abnormal congruence angles, better patellar medialization, and higher peak torque of the hamstring.³²
The technique of Roux-Goldthwait procedure is described later in this chapter in detail.