Adolescent patellar instability

Abstract

Patellar instability most frequently presents during adolescence. Congenital and infantile dislocation of the patella is a distinct entity from adolescent instability and measurable abnormalities may be present at birth. In the normal patellofemoral joint an increase in quadriceps angle and patellar height are matched by an increase in trochlear depth as the joint matures. Adolescent instability may herald a lifelong condition leading to chronic disability and arthritis. Restoring normal anatomy by trochleoplasty, tibial tubercle transfer or medial patellofemoral ligament (MPFL) reconstruction in the young adult prevents further instability. Although these techniques are proven in the young adult, they may cause growth arrest and deformity where the physis is open. A vigorous non-operative strategy may permit delay of surgery until growth is complete. Where non-operative treatment has failed a modified MPFL reconstruction may be performed to maintain stability until physeal closure permits anatomical reconstruction. If significant growth remains an extraosseous reconstruction of the MPFL may impart the lowest risk to the physis. If minor growth remains image intensifier guided placement of femoral intraosseous fixation may impart a small, but acceptable, risk to the physis. This paper presents and discusses the literature relating to adolescent instability and provides a framework for management of these patients. Cite this article: Bone Joint J 2017;99-B:159-70.

Clinical Outcomes After the Nonoperative Management of Lateral Patellar Dislocations: A Systematic Review

“…It is also commonly used for patients with more than 1 dislocation, and many authors do not advocate surgical treatment until a course of nonoperative treatment has been deemed to have failed. 12 , 59 One of the main findings of this systematic review was that mean PROM scores after nonoperative treatment were high on the whole but did not represent normal function in any of the studies, 38 with the Kujala score and the Knee injury and Osteoarthritis Outcome Score in the larger series mostly approximating 80% of the maximum score.…”

“…Nonoperative treatment is a common management option for lateral patellar dislocations 12 , 59 and is widely used in the case of a first-time patellar dislocation. It is also commonly used for patients with more than 1 dislocation, and many authors do not advocate surgical treatment until a course of nonoperative treatment has been deemed to have failed.…”

“…It is often considered to be the first-line treatment for patellar instability. 12 , 59 One of the challenges around nonoperative management is the complexity of the interventions offered and the different approaches to rehabilitation taken in different centers. Various physical therapy techniques have been described with the aims of strengthening the quadriceps muscles; restoring range of movement; addressing deficiencies in hip, trunk, or foot biomechanics that may precipitate instability; reducing pain; and improving patient confidence.…”

The “Journal of Functional Morphology and Kinesiology” Journal Club Series: Highlights of Recent Papers in Pediatric Exercise

“…Although surgical reconstruction of MFPL, as the primary treatment of patellar dislocation, is widespread among orthopedic surgeons, conservative treatment, consisting of physical exercises and immobilization techniques, is generally indicated after the first episode of patellar dislocation. After a period of 2-3 weeks of orthosis or brace immobilization with 15 to 30 degrees of flexion [7], non-operative management consists of the optimization of the neuromusculoskeletal system, muscle recruitment and strengthening, (glutei, quadriceps, hamstring, and calf complex), providing dynamic stability [8]. In the literature, the reconditioning of the vastus medialis obliquus muscle is considered as the principal aim of physical therapy; in fact, it promotes successful healing of the MPFL, improving neuromusculoskeletal control, and preventing further dislocations [8].…”

Trochleoplasty: Indications and Technique

“…Patellar instability results when maltracking becomes symptomatic. Authors variably define symptomatic instability as patient reported apprehension during knee range of motion, a single dislocation/subluxation event, or recurrent dislocations [6,[8][9][10]. A patient sustaining a first-time dislocation has a 17% chance of re-dislocating in 5 years, whereas a patient with abnormal or painful patellar motion preceding their index dislocation has a recurrence rate up to 49% [11].…”