Lateral release of the patella: indications and contraindications

The effects of patellar taping on patellofemoral incongruence. A computed tomography study

Patellar taping for the purpose of patellar medialization is a nonoperative rehabilitation technique used in the treatment of patellofemoral pain. Despite early reports of excellent success rates, the indications for this treatment and its efficacy on patellofemoral pain are unclear. The present computed tomography study was undertaken to evaluate the effect of patellar taping on patellofemoral incongruence. Sixteen female patients (age range, 16 to 25 years) with anterior knee pain related to patellofemoral incongruence underwent computed tomography examination with their quadriceps muscles relaxed and contracted both before and after patellar taping. Patellar lateralization was measured as lateral patellar displacement, and patellar tilt was measured as lateral patellar angle. Patellar taping did not significantly affect patellofemoral lateralization or tilt. The results of this study do not support the use of this method for passive correction of patellofemoral incongruence. Although patellar taping may well be effective in controlling anterior knee pain during physical therapy, it does not do so by medializing the patella.

Delayed proximal repair and distal realignment after patellar dislocation

Twenty athletes with distal malalignment who sustained unilateral traumatic patellar dislocation remained impaired by chronic instability. Surgery was performed at a mean age of 18 years. Posttraumatic attenuation of the medial patellofemoral ligament was repaired near the margin of the patella in 10 knees and avulsion or attenuation posterior to the vastus medialis obliquus in 10 knees. Advancement of the medial patellomeniscal ligament at the margin of the patella and normalization of the Q angle to 10 degrees by tibial tubercle osteotomy were performed in each knee. Distal lateral retinacular release without release of the normal vastus lateralis tendon was performed. Results were judged according to Turba et al, and activity levels were evaluated per guidelines of the International Knee Documentation Committee. Eighteen (90%) patients achieved good or excellent results and were unimpaired at a minimum of 24 months. Two patients achieved fair subjective results with some impairment in vigorous activity. There was no recurrent instability. Radiographically, the mean preoperative patellofemoral congruence angle improved from 20 degrees to 0 degree. Athletes who sustain an initial traumatic patellar dislocation after physeal closure and in whom conservative management fails can be treated successfully by repair of the medial patellofemoral ligament at the site of disruption and advancement of the medial patellomeniscal ligament combined with correction of an elevated Q angle.

Knee dislocation. Complications of nonoperative and operative management

Because of the nature and extreme severity of the injury, complications will continue to be a common denominator in traumatic knee dislocations. The major complications that cause significant morbidity, including amputation and death, are now relatively infrequent. Prompt recognition and treatment of these complications are of utmost importance to assure functional viability of the extremity. These complications must continue to be addressed preoperatively and postoperatively. Minor complications will persist after significant knee surgery. New complications will evolve as newer techniques, instrumentation, and procedures are introduced. Ligament reconstructive surgery is relatively new and technically demanding. The surgeon must continue to use meticulous technique and attention to detail. Orthopedic surgeons must continue to closely evaluate the procedures they perform, making sure they are as technically correct as possible. Each surgeon must observe and determine what technique will be of true benefit to the patient. Most complications that do occur can be corrected or at least improved if they are handled early and with a true understanding of the problem.

Biomechanical considerations for rehabilitation of the knee

Knowledge of the anatomy and biomechanics of the knee is critical for successful rehabilitation following knee injury and/or surgery. Biomechanics of both the tibiofemoral and patellofemoral joints must be considered. The purpose of this paper is to provide a framework for rehabilitation of the knee by reviewing the biomechanics of the tibiofemoral and patellofemoral joints. This will include discussion of the relevant arthrokinematics as well as the effects of open and closed chain exercises. The implications for rehabilitation of the knee will be highlighted.

Clinical evaluation of patients with patellofemoral disorders

Accurate clinical evaluation of patients with patellofemoral disorders is the cornerstone of effective treatment. This article defines how a careful history and physical examination can direct strategies for nonoperative and operative management. A critical analysis of traditional methods of evaluation and a streamlined rational approach to clinical evaluation is presented. Key questions and important physical findings that affect treatment decisions are emphasized.

The three-in-one proximal and distal soft tissue patellar realignment procedure. Results, and its place in the management of patellofemoral instability

The three-in-one procedure for extensor mechanism realignment of the knee combines lateral release, vastus medialis obliquus muscle advancement, and transfer of the medial one-third of the patellar tendon to the tibial collateral ligament. We observed 37 patients (42 knees) receiving this treatment at a minimum 25-month follow-up (range, 25 to 85 months; mean, 44). Thirty-two of 42 knees (76%) with recurrent patellar dislocation had good or excellent results after surgery. Redislocation occurred in four knees (9.5%). Skeletal immaturity, chondral damage, and generalized ligament laxity did not seem to affect outcome. Thirty patients (37 knees) were studied 2 years earlier as well (mean follow-up, 29 months). When comparing the results 2 years later, there was a significant deterioration in outcome over time. These results are comparable with the published results for other techniques of patellar stabilization. We describe the place of the three-in-one operation in our surgical protocol for patellofemoral instability, which is based on the principle that a procedure should be selected to address the underlying pathologic features in an individual case rather than always using one operation for all cases.

Medial soft tissue restraints in lateral patellar instability and repair

This study was undertaken to evaluate the medial ligamentous stabilizers of the patella in restraining lateral displacement and to assess their relative contribution after individual repair. Seventeen fresh frozen human anatomic specimen knee joints were studied. The specimens were loaded onto a testing instrument that was designed to measure the compliance of the medial and lateral patellar restraints in the coronal plane. Two different cutting and repair sequences were used to test the individual contributions of the patellar ligaments. The medial patellofemoral ligament was found to be the major medial ligamentous stabilizer of the patella. Isolated release resulted in a 50% increase in lateral displacement, and isolated repair restored balance to the patella. In addition, the patellotibial and patellomeniscal ligament complex played an important secondary role in restraining lateral patellar displacement. Isolated repair of these ligaments restored balance to near normal levels. The medial patellofemoral retinaculum played only a minor role in patellofemoral instability. Proximal realignment or medial ligament repair for patellofemoral instability specifically should address repair of the deep layers that contain the restraints to lateral patellar displacement. Failure to include these structures in repair, especially of the medial patellofemoral ligament, may lead to persistent or recurrent instability.

Patellofemoral pain: let the physical exam define treatment

The complex causes of patellofemoral disorders are most effectively identified through a systematic evaluation of a patient's lower-extremity alignment, patellar mobility, muscle flexibility, strength, and coordination as well as an assessment of soft-tissue and articular pain. By combining information from such an exam with a careful history and appropriate radiographic studies, the physician can make a specific diagnosis. This sets the stage for an optimal rehabilitation prescription, which usually will involve some combination of muscle flexibility and strength training, taping, orthoses, analgesics, and therapy with heat and ice.

Open or arthroscopic lateral release. Indications, techniques, and rehabilitation

Careful patient selection, accurate surgical technique, and careful postoperative rehabilitation are all equally important to success in lateral release surgery. Whether the surgery is performed by open or arthroscopic technique, one must release all layers of the retinaculum, spare the vastus lateralis, extend the release far enough distally, check intraoperative patellar mobility, and obtain absolute hemostasis. Postoperative rehabilitation must stress pain control, early quadriceps contraction, patellar mobility, and knee motion. With attention to these details, successful lateral release surgery is likely in most patients with pathologic lateral patellar tilt and minimal patellofemoral arthrosis.

Patellofemoral Instability: Evaluation and Management

Patellofemoral disorders are a common cause of knee pain and disability. A thorough history and a careful physical examination are essential to accurate diagnosis, and imaging modalities play an important role. Magnetic resonance imaging can provide information on malalignment and soft-tissue injuries. Although there is a continuum of diagnoses, most patellofemoral disorders can be divided into three distinct categories: soft-tissue abnormalities, patellar instability due to subluxation and dislocation, and patellofemoral arthritis. Many patellofemoral disorders respond to nonoperative therapy. When surgical intervention is necessary, patellar tilt can be successfully treated by a lateral release. Lateral patellar subluxation associated with malalignment can be corrected by a distal realignment procedure such as the anteromedial tibial tubercle transfer. Repair of the medial patellofemoral ligament in cases of patellar dislocation has considerably lowered the incidence of recurrent instability. Although no ideal treatment exists for patellofemoral arthritis, mechanical symptoms may be alleviated by arthroscopic debridement of delamination lesions. Articular cartilage-wear disorders may be stabilized by addressing the primary causative disorder.

Allograft versus autograft anterior cruciate ligament reconstruction: 3- to 5-year outcome

Sixty-four patients whose knees underwent anterior cruciate ligament reconstruction with nonirradiated allograft tissue were compared with 26 patients whose anterior cruciate ligaments were reconstructed using autograft tissue 3 to 5 years after their operation. Detailed symptoms, activity-level, and functional outcomes, physical examination, and instrumented knee testing were recorded. No statistically significant differences were found except a higher incidence of loss of terminal extension in the autograft group. These differences were small and not considered clinically significant. Laxity and knee scores were similar in both groups. According to International Knee Documentation Committee ratings, overall outcome was normal or nearly normal in 48% of the allograft patients and in 38% of the autograft patients. Overall subjective rating with the Cincinnati Knee Score was 85.8 for the allograft patients and 84.5 for the autograft patients. Allograft tissue provides an acceptable alternative to autograft tissue for reconstruction of the anterior cruciate ligament.

Patellar taping in the treatment of patellofemoral pain. A prospective randomized study

The purpose of this prospective study was to evaluate the efficacy of a patellar taping program in the conservative management of patellofemoral pain. Twenty-five patients with patellofemoral pain were randomized into two groups. One group underwent a standard physical therapy program for patellofemoral pain. The other group underwent the same physical therapy program, but use of a patellar taping technique was added to this program. Results of a subjective visual analog scale and changes in isokinetic strength and electromyographic activity of the quadriceps muscle were analyzed. Both the tape and no-tape groups experienced a statistically significant decrease in symptoms (P < 0.05), but no difference in improvement of patellofemoral pain was noted between the groups. Likewise, both groups demonstrated significant improvement in quadriceps muscle isokinetic strength (P < 0.05) and activity (P < 0.001), but no difference in improvement was noted between groups. The results of this study suggest no beneficial effect of adding a patellar taping program to a standard physical therapy program in the conservative treatment of patellofemoral pain. Larger prospective studies are warranted to support this opinion.

Instrumented measurement of patellar mobility

To provide an objective analysis of medial and lateral patellofemoral laxity, we examined 94 uninjured athletic subjects and 22 patients with unilateral lateral patellar dislocation. We developed an instrument to measure the compliance of the medial and lateral patellar restraints. The instrument recorded the force-displacement relationship as the patella was pushed medially and laterally. Subtracting the medial displacement from the lateral displacement at a given force level allowed the tester to assess the peripatellar soft tissue "balance." The results for both the 2.5- and the 5-pound tests were significant. Paired comparisons differentiated the three groups, with significant differences between control and affected (P = 0.0001), control and contralateral (P = 0.0036), and affected and contralateral (P = 0.0157) knees. The mean result of the lateral minus medial displacement test for our sample population of control subjects was -2.1 mm for the 5-pound test. A negative value in this test indicates that medial displacement exceeds lateral displacement. This finding was present in 81% of control subjects. In contrast, the mean result for the patients' affected knees was +3.2 mm for the 5-pound test. Using the value of 0.0 mm as the diagnostic determinant for peripatellar imbalance, we found a test sensitivity of 91% and a specificity of 81%.

A biomechanical comparison of lateral retinacular releases

A lateral patellar retinacular release that transects the tendon of the vastus lateralis muscle may result in significant complications. To avoid such complications, the superior extent must be limited, and maximizing the inferior extent may be important in achieving an adequate release. The effective release of the patella from its lateral retinaculum was examined for 2 incision lengths using 10 fresh-frozen human cadaveric knees and comparing the medial displacement of the patella relative to the femur for 3 study groups (control, intact retinacula; Group A, retinacula cut from the inferior third of the vastus lateralis tendon down to the anterolateral arthroscopic portal; and Group B, retinacula cut from the inferior third of the vastus lateralis tendon down to the tibial tubercle) when a 22-N medially directed force was applied to the patella with the knee at 30 degrees and 60 degrees of flexion. The extended release (Group B) resulted in a significantly more effective release when compared with the standard release (Group A) or control group. This technique may allow an adequate release of the patella while preserving the function of the vastus lateralis muscle.

Knee pain diagrams: correlation with physical examination findings in patients with anterior knee pain

All new patients who presented with knee problems were asked to fill out standard knee pain diagrams before being evaluated. Completed diagrams were not seen by the examining physicians. After obtaining the history and performing the physical examination, one of four physicians marked an identical diagram with the areas of tenderness. Ninety patients with a provisional diagnosis of patellofemoral pain completed 109 (19 bilateral) pain diagrams. Evaluation of the diagrams was quantitated by division of the diagrams into nine zones. The researcher grading the diagrams was blind to whether the diagrams were drawn by the patient or physician. Patients marked an average of 4.23 zones per knee compared with 2.66 zones for physicians. In 88% (96 of 109) of the knees, the physician diagram included all or some of the zones marked by the patients. Eighty-five percent of all zones marked by physicians were included in patient diagrams. Eighty-six percent of negative patient zones correctly predicted a negative examination. Overall frequency of positive findings in each of the nine zones was consistent between patient and physician diagrams. A physician can be confident that findings of tenderness will likely be within zones marked by a patient on a standard diagram of the knee. Pain diagrams facilitate proper diagnosis by correctly directing attention to areas of tenderness in a large percentage of cases and provide an inexpensive and highly useful prediction of areas of anterior knee tenderness in patients with patellofemoral pain.

The quantitative measurement of normal passive medial and lateral patellar motion limits

To quantify normal motion, medial and lateral passive patellar motion limits were measured in 67 high school athletes randomly selected from a group of 1340 athletes undergoing preseason physical examinations. Patellar displacement was measured at knee flexion angles of 0 degree and 35 degrees, using both a Patella Pusher (a hand-held force gauge) and a manual technique, and the results were compared. Demographic data and physical examination of the deceleration mechanism (Q angle, vastus medialis obliquus dysplasia, patella alta and baja, and valgus and varus alignment) were correlated with patellar motion limits. With the knee in extension, passive displacement of the patella averaged 9.6 mm medially and 5.4 mm laterally. In flexion, medial displacement averaged 9.4 mm and lateral displacement averaged 10.0 mm. No positive correlations were found between demographic data or deceleration mechanism examination parameters and patellar motion limits, suggesting that motion produced by the displacement force was limited by ligamentous restraints only. The clinical assessment of the passive limits of patellar motion should include examination at knee flexion angles of 0 degree and 35 degrees. The manually produced displacement was found to be more reproducible than displacement by the Patella Pusher (P < 0.05).

The relationship between quadriceps angle and anterior knee pain syndrome

Anterior knee pain syndrome (AKPS) represents a significant challenge for patients and for clinicians. The purposes of this study were: 1) to determine the reliability of the Q-angle measurement, 2) to quantify Q-angle changes that occur with knee flexion, and 3) to determine if subjects with AKPS (N = 52) have a significantly different Q-angle than subjects without AKPS (N = 50). With the knee in an extended position, intratester Q-angle intraclass correlation coefficients (ICC) ranged from .84 to .90, and standard error of measurement (SEM) values ranged from 2.01 to 2.23 degrees. Intertester Q-angle ICC was .83, and the SEM was 2.49 degrees. With the knee flexed, the intratester ICC was .83 for both testers, and SEM values ranged from 0.68 to 2.45 degrees. Intertester ICC and SEM were .65 and 3.50 degrees, respectively. No significant difference was found in intratester Q-angle values between the extended and flexed knee positions (p > 0.05). No significant difference in Q-angle was found between asymptomatic subjects (11.1 +/- 5.5 degrees) and symptomatic subjects (12.4 +/- 5.1 degrees) (p = 0.07). Increased Q-angles were not responsible for AKPS in this group of patients. Other factors were hypothesized to be responsible for their symptoms.

Effects of variation on extensor elements and operative procedures in patellofemoral disorders

The influence of both insertion and strength/elasticity of each extensor in patellofemoral disorders was fully investigated through a two-dimensional mathematical model analysis in a horizontal plane, in combination with experimental design theory for analyzing mutually correlated influences. In the model, patellofemoral joint profiles projected on a horizontal plane have been expressed as spline functions. Each muscle of the quadriceps has been represented as a string pulled by the respective force; fascias and tendons have been represented by springs. Nonlinear equations have been constructed to represent the forces involved, and then solved by numerical iteration. An analysis of variance was performed on the data derived from a series of simulations, obtaining the following results. The strength of most extensors has been shown to have an influence on the increase in lateral contact force but not patellar translation. The tibial tubercle position has significant influence on both patellar translation and lateral contact force. The quadriceps' insertion on the femur has no influence on patellar translation. The insertion of each extensor on the patella has been shown to have a strong effect on patellar translation but not on contact force.

Loss of motion after anterior cruciate ligament reconstruction

We did a retrospective review and follow-up examination to investigate the incidence, risk factors, and outcome of patients who developed loss of motion after arthroscopic anterior cruciate ligament reconstruction. Two hundred forty-four patients with a minimum followup of 1 year were reviewed. Loss of motion (defined as a loss of extension of more than 10 degrees or flexion of less than 125 degrees) was identified in 27 patients for an overall incidence of 11.1%. Factors associated with loss of motion included acute reconstruction (less than 1 month from initial injury), male sex, and concomitant medial collateral ligament repair or posterior oblique ligament reefing or both. Twenty-one patients required surgery to regain their motion; three patients required a second procedure. Twenty-one of 27 patients with loss of motion underwent a detailed followup and were compared with 24 randomly chosen controls who had a normal range of motion after anterior cruciate ligament reconstruction. At followup, patients who experienced loss of motion had a significant decrease in noninvolved to involved knee extension and flexion compared to the control patients. There was no difference between our patients and the controls regarding patellofemoral problems, anterior knee laxity, and functional strength. Sixty-seven percent of patients with loss of motion had a good or excellent result in comparison to 80% of the controls.