Jack C. Hughston

Treatment of acute patellar dislocation

To determine the effectiveness of nonoperative and operative treatment of initial acute patellar dislocation, we reviewed the charts of 399 patients with the diag nosis of an acute dislocation, seen during a 30 year period. One hundred patients (103 knees) met the criteria for inclusion in the study. The average age of the patient at injury was 21.7 years (range, 9 to 72 years). Length of followup aver aged 8 years (range, 2 to 26 years). Retrospectively, we divided the patients into two groups, according to the examination of their unaf fected knee. Group I (69 knees) showed evidence on examination of congenital abnormality of the extensor mechanism in the unaffected knee, indicating a predis position to dislocate with less significant trauma. Group II (34 knees) showed no clinically perceptible congenital predisposition to dislocate based on examination of the unaffected knee. In the nonoperatively treated knees in Group I, there was a 52% (28/54) incidence of good or excellent results. The nonoperatively treated knees in Group II had a 75% (15/20) incidence of good or excellent results. Acute dislocation occurred more frequently in males than in females. Recurrence was rarer in patients whose initial dislocation had occurred when they were over 15 years old. Contrary to recently published reports, primary acute traumatic patellar dislocations can be treated with non operative therapy with good or excellent results. Initial evaluation should include examination of the uninvolved knee which, if found to have signs of congenital abnor mality, would indicate a worse prognosis.

The posterolateral drawer test and external rotational recurvatum test for posterolateral rotatory instability of the knee

Posterolateral drawer tests and external rotational recurvatum tests are used to detect posterolateral rotatory instability. A specific manner of performance of these tests is necessary to properly interpret the nature of acute and chronic knee conditions. The posterolateral drawer test is performed at 80 degrees of knee flexion and is maximum in 15 degrees of external rotation. Since the posterior cruciate ligament is intact in posterolateral rotatory instability, the posterior drawer will be negative on maximum internal tibial rotation. Fibrous scar tissue may conceal an otherwise positive posterolateral drawer sign in the chronic condition. The external rotational recurvatum test examines the knee in extension. Tightness and spasm of the biceps femoris and semimembranosus may obscure a positive external rotational recurvatum test in the acute or chronic condition. The external rotational recurvatum test will be negative when the anteromedial and intermediate bundles of the anterior cruciate ligament are intact owing to their contact with the intercondylar shelf in extension. The posterolateral drawer and the external rotational recurvatum can be subtle tests and require careful observation for accurate evaluation of both the acute or chronic condition of the knee joint.

Medial subluxation of the patella as a complication of lateral retinacular release

We examined 54 patients (60 knees) referred to us because of their failure to improve, or because of a worsening of their preoperative symptoms, following an arthroscopic lateral retinacular release. Thirty knees developed medial subluxation of the patella postoper atively. This disabling condition is new to us. It is previously unreported as a complication of arthroscopic lateral retinacular release. Anterior knee pain was the only reported preoperative symptom in 14 knees. Six teen knees had a preoperative diagnosis of lateral patellar subluxation on the basis of a positive appre hension sign only. Eighteen of 30 knees had no surgery of the extensor mechanism other than the arthroscopic lateral release. The remainder additionally underwent varying types and numbers of operations in an attempt to resolve their disability. CAT scan evaluation of three patients who volun teered for the procedure demonstrated severe atrophy and retraction of the vastus lateralis. Loss of this dy namic lateral stabilizer contributed to the medial sub luxation of the patella.

Acute combined posterior cruciate and posterolateral instability of the knee

This report concerns 13 consecutive patients (13 knees) who underwent operative treatment for acute combined posterior cruciate and posterolateral instabil ity due to combined injury to the posterior cruciate ligament and the arcuate ligament complex. Our pur pose was to examine the method of diagnosis and the results in these patients. There were 12 males and 1 female (average age, 26 years). Five patients were injured in a motor vehicle accident, four in sports activ ities, and four in nonsports activities. The mechanism of injury was an anteromedial blow to the flexed knee in six patients, a fall onto the knee in two, and unknown in five patients. Eleven patients were available for fol low-up evaluation (average, 56 months), and in each the result was rated as good, fair, or poor. In 10 patients (90%) the results were rated as good subjectively, in 11 (100%) as good functionally, and in 8 (73%) as good objectively. Injury to both the posterior cruciate liga ment and the arcuate ligament complex can result from rotational force that can be due to a blow to the anteromedial aspect of the knee. Diagnosis can be made by a combined positive response to the posterior drawer test, the anterior drawer test performed with the tibia in internal rotation, the abduction and adduc tion stress tests performed with the knee in full exten sion, the posterolateral drawer test, and the external rotation-recurvatum test. In a knee with concomitant injury to the posterior cruciate ligament and the arcuate ligament complex that requires surgical repair, all in jured structures should be explored and repaired to ensure a subjectively, objectively, and functionally good result.

Reconstruction of the posterior cruciate ligament.

Chronic disabling posterior cruciate ligament instability has not been demonstrated to have a satisfactory solution. This documentary reports our experiences and results in the last ten years using the medial gastrocnemius tendon as a posterior cruciate ligament substitute. Limited reports of other surgical techniques have cited only a few cases, with short follow-up and minimal documentation. It is our purpose to describe the selection of cases requiring reconstruction, the preoperative management, surgical technique and postoperative care, and to present the subjective, functional, and objective results.

Fractures of the posterolateral tibial plateau

We reviewed the clinical records and operative notes of 28 patients with fractures of the posterolateral tibial plateau seen at our institution from 1949 to 1982. Five of the 28 patients had chronic depressions of the posterolateral tibial plateau after initial treatment else where. All five were disabled because of significant functional instability when the knee was in flexion. There were 23 acute fractures, of which 4 were initially nondisplaced and treated nonoperatively. One nonop erative patient was lost to followup; the remaining three were rated as having had good or excellent results. Nineteen patients had acute depressed fractures and were treated operatively with open reduction, elevation of the depressed area, and bone grafting, with or without internal fixation. All patients treated operatively at the time of injury were seen for followup from 24 to 145 months postoperatively, with a mean followup of 59 months. One patient was lost to followup; the other 18 were rated using both objective and subjective criteria. Seventeen (94%) achieved a final rating of excellent or good; one patient (6%) achieved a rating of fair. We have observed these fractures occurring in a younger population and producing significant disability in activities requiring a stable knee in flexion. The depressed posterolateral tibial plateau fracture is best assessed by AP, lateral, and 45° internal oblique views on radiographic examination. Because of continued disability caused by chronic, depressed fractures of this type, we recommend open reduction and bone grafting in acute cases to eliminate instability in flexion. This procedure produces good or excellent results in most cases.

Disruption of the vastus medialis obliquus with medial knee ligament injuries

We reviewed the clinical records of 189 consecutive surgically treated acute ligamentous injuries of the me dial compartment of the knee to determine the preva lence of disruptions of the vastus medialis obliquus muscle and to document the results of simultaneous repair of the disruption. Forty knees (40 patients) dem onstrated a vastus medialis muscle disruption at the time of surgical repair for the medial ligamentous dis ruption. All were surgically corrected and the sites of tearing were documented. The vastus medialis obliquus muscle was ruptured from the adductor tubercle in 31 (78%) knees. Of these, the tibial collateral ligament was torn from its femoral attachment in 19 (61 %) knees and the meniscofemoral portion of the capsular ligament ligament was torn from its femoral attachment in 23 (74%) knees. The vastus medialis obliquus muscle was ruptured from the patella in seven (18%) knees and was ruptured interstitially in nine (23%) knees. Each of the 40 patients returned for objective, subjective, and functional follow-up evaluation (average, 39 months). At follow-up examination, 88% of the 40 knees were rated as good subjectively, 90% objectively, and 93% functionally. A high correlation exists between tears of the vastus medialis obliquus muscle from its femoral attachment and tears of the medial compartment liga ments from their respective femoral attachments. Sur gical repair of disruptions of the vastus medialis obli quus muscle at the time of primary repair of injury to the ligaments of the medial compartment of the knee can prevent subsequent disorder of the extensor mech anism and can produce an objectively, subjectively, and functionally stable knee.

Roentgenographic findings in pigmented villonodular synovitis of the knee

Twenty-nine cases of pigmented villonodular synovitis (PVS) of the knee in 27 patients were reviewed to determine characteristic roentgenographic findings. All cases met strict histologic criteria for diagnosis. Four cases were localized PVS (LPVS), and 25 cases were diffuse PVS (DPVS). Roentgenographic findings were largely in the soft tissues. Cystic invasion of bone or degenerative changes were rare, although present in some cases. When present in DPVS, these changes were most pronounced in the patellofemoral articular surface. In the cases of DPVS, large posterior tumefactions did not correlate with extraarticular extension. Clinical behavior of PVS was governed more by anatomic site and form of disease than by the severity of histologic or roentgenographic findings.

Popliteal cyst: a surgical approach.

Twenty-nine adult patients (30 knees) who failed conservative treatment had surgical excision of a non-rheumatoid cyst. To determine the effectiveness of this surgical procedure, we reviewed the cases of 24 patients (25 knees) who were available for subjective and objective follow up. Twenty of the 25 knees (80%) were rated excellent or good. Three knees had fair results. Two knees continued to have problems and ultimately underwent total knee replacement for degenerative arthritis.

Combined anterolateral-anteromedial rotatory instability of the knee.

Rotational instability of the knee is a descriptive classification of knee ligament instability based upon functional disability and clinical examination. Rotatory instability requires a pivot, or post, around which the femur and tibia rotate in relation to each other. In rotatory instabilities, the intact posterior cruciate ligament is the rotational axis between the femur and tibia. During the clinical examination of the knee, the femur is a fixed portion of the lower limb, and the term rotatory instability is based upon the direction the tibia moves in relationship to the femur in the axial plane. In anteromedial rotatory instability, the medial tibial plateau subluxes anteriorly and rotates externally in relationship to the femur. Conversely, in anterolateral rotatory instability, the lateral tibial plateau comes forward in the axial plane (subluxes anteriorly) and rotates internally in relationship to the femur. Posterolateral rotatory instability refers to a posterior subluxation and lateral rotation of the lateral tibial plateau about the axis of the intact posterior cruciate ligament. Posteromedial rotatory instability has not been documented clinically because the posterior cruciate ligament tightens with internal rota-