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PubMed2002

Current concepts of lateral patella dislocation.

Surgical treatment of patellar dislocations, acute and chronic, has evolved significantly over the past decade with the advance of biomechanical knowledge of patellofemoral restraints and injury patterns identified by physical examination and improved imaging techniques. There continues to be no consensus on treatment parameters. Despite the presence of predisposing factors, such as dysplasia or generalized hyperlaxity, medial retinacular injury associated with primary (first-time) patellar dislocations represents a ligament injury, which may result in residual laxity of the injured structure. This residual laxity is defined objectively by an increase in passive lateral excursion of the patella. Repair or reconstructive procedures to restore this medial constraint is considered paramount in any procedure to stabilize the patella against subsequent dislocations. How best to accomplish this continues to be a matter of debate. The establishment of a medial check-rein by either repairing or reconstructing the MPFL is the procedure of choice for stabilizing a kneecap after first-time dislocation, largely because the literature to date does not provide clear guidelines about when more extensive surgery is indicated. Whether or not all first-time dislocators have improved outcome after surgical repair remains speculative, however. Improved outcome would involve both the elimination of recurrent instability episodes and continued satisfactory function of this patella in activities-of-daily-living and sporting activities. These outcomes have not been studied critically in operative versus nonoperative treatment of first-time patellar dislocation. For the first-time dislocator, most investigators would agree that an arthroscopy should be performed if intra-articular chondral damage is suspected. Nonoperative management of first-time patellar dislocations continues to be the preferred practice pattern in the United States. If surgical management is elected, because of individual characteristics of the injury pattern or the patient's lifestyle, it is important to inspect the MPFL along its length and repair any or all ligamentous disruptions. If the ligament is avulsed from the medial epicondyle, reattachment to bone is necessary to restore passive restraint to lateral patella motion. MRI may be useful in order to identify the location and degree of medial soft tissue injury preoperatively. The establishment of a medial check-rein by either repairing or reconstructing the MPFL is a necessary component of all surgical procedures performed to correct objective lateral instability of the patella. The addition of a LRR should be additive to this procedure only when it facilitates other procedures to recenter the patella or when objective lateral tilt by physical examination measurements is present. A practical approach to surgery after patellar dislocation is the minimal amount of surgery necessary to re-establish objective constraints of the patella. Correcting dysplastic factors, in particular tibial tubercle transfers and trochleoplasties, are best reserved if more minimal surgery has failed. This failure is defined as continued functional instability of the kneecap.

Arthroscopy↗
PubMed1996

The Insall-Burstein posterior stabilized total knee replacement in the valgus knee.

Sixty-seven Insall-Burstein (Zimmer Inc, Warsaw, Indiana) posteriorly stabilized total knee replacements were implanted in knees with a preoperative alignment > 10 degrees of valgus (average: 19.5 degrees). An anteromedial approach with release of the lateral ligaments of the femur was used. A lateral patellar release was necessary in 49% of cases. Fifty-one knees (76%) were reviewed with an average follow-up of 6 years. Pain at follow-up was absent or mild in all of the knees except one with aseptic loosening of the tibial and patellar components. The average flexion was 105 degrees. The results according to the Knee Society Rating System were excellent in 53%, good in 39%, fair in 6%, and poor in 2%. A patellofemoral "clunk" was present in three knees (6%), and one knee required arthroscopic debridment. The mechanical axis was within 5 degrees of neutral in 88%. A survivorship analysis was performed using failure requiring reoperation as the end point. There were four failures due to aseptic loosening, symptomatic lateral ligamentous instability, deep infection, and recurrent patellar dislocation. The patellar component had not been implanted in the knee with recurrent patellar dislocation due to severe bony erosion. The cumulative success rate was 95% at 10 years. These results indicate that release of the contracted lateral structures and implantation of a posteriorly stabilized prosthesis achieve a stable and well-aligned knee in 66 out of 67 knees. Attention must be paid to patellar tracking and realignment of the extensor mechanism.

Adult↗
PubMed1995

Is there a place for patellofemoral arthroplasty?

Indications for patellofemoral arthroplasty were studied based on a 2- to 10-year followup review. Of 183 patellofemoral prostheses implanted between 1980 and 1990, 104 were associated with unicompartmental arthroplasty, and 79 were implanted alone. Thirteen patients were lost to followup. The results of 66 patellofemoral arthroplasties are reported at an average followup of 66 months. The mean age of the patients at surgery was 57 years. Underlying causes of the osteoarthritis included patellar dislocation or dysplasia (22), patellar fracture (20), and primary osteoarthritis (24). A metallic femoral groove was associated with a polyethylene patella with no metal backing. Two (9%) prostheses were revised in the dysplasia group, 1 (5%) in the posttraumatic group, and 7 (29%) in the primary osteoarthritis group. In this latter group, the indications of patellofemoral arthroplasty must be restricted to lesions of the patellofemoral joint in a knee in neutral axis evaluated preoperatively on full standing and stress radiographs. The best results of patellofemoral arthroplasty were obtained in osteoarthritis after patellar dislocation or patellar fracture.

Activities of Daily Living↗
PubMed1995

[The value of MR tomography in traumatic patella dislocations].

PURPOSE: To describe the MR imaging findings in patients with lateral patellar dislocation. MATERIAL AND METHODS: The MRIs of 31 patients with patellar dislocation were evaluated retrospectively. Arthroscopic surgery was performed in 23 cases. RESULTS: Hemarthrosis was found in 30/31, contusions of the lateral femoral condyle in 30/31 and of the medial patellar facet in 26/31 cases. Injury of the medial patellar retinaculum was seen in 28/31 cases. Osteochondral fractures were found in 18 patients; compared to arthroscopy there were one false-positive and 5 false-negative findings concerning loose cartilage bodies. In 7 cases, patellar dislocation was not suspected before MR imaging. CONCLUSION: Hemarthrosis, lateral femoral and medial patellar contusion, and retinacular disruption are typical findings after lateral patellar dislocation. A careful search for free osteochondral fragments is mandatory as it influences the indication and performance of arthroscopic surgery.

Adolescent↗
PubMed1992

Patella alta and recurrent dislocation of the patella.

Fifteen knees were treated with a surgical technique designed for recurrent patellar dislocations when associated with patella alta. The average number of patellar dislocations preoperatively was 12, and the determination of patella alta was made using the technique described by Insall and Salvati, which is a ratio of the length of the patellar tendon to the longest diagonal length of the patella. The normal value for this ratio is 1.02 plus or minus 20%. The average preoperative ratio in this study was 1.58 (range, 1.2-2.1), which changed to 1.08 (range, 0.99-1.14) by the time of follow-up examination. The surgical technique used involves transposing the patellar tendon insertion distally without any medialization or recessing and allows for good bone contact for healing, secure fixation, and immediate postoperative motion. There were no recurrences of patellar dislocation postoperatively and few complications. Only one patient complained of anterior knee pain in the follow-up period. This technique is thought to give good results when it is used specifically for recurrent patellar dislocations associated with patella alta.

Adolescent↗
PubMed2005

A simple technique for reconstruction of the medial patellofemoral ligament using a quadriceps tendon graft.

Numerous surgical procedures have been described for the treatment of recurrent patellar dislocation. Studies have shown that the primary pathoanatomy associated with lateral patellar dislocation is injury to the medial patellofemoral ligament (MPFL), which is the major soft-tissue restraint to lateral patellar translation. Recently, various procedures have been described that address the medial ligamentous injury inherent to lateral patellar dislocation. We present a simple technique for MPFL reconstruction using a quadriceps tendon graft.

Arthroscopy↗
PubMed2004

Medial patellofemoral ligament reconstruction for recurrent patellar instability.

The purpose of this study was to determine the value of reconstruction of the medial patellofemoral ligament (MPFL) in the treatment of recurrent patellar dislocation and subluxation. We retrospectively reviewed 40 randomised patients with recurrent patellar dislocation or subluxation, who had undergone realignment surgery from July 1999 to December 2001. Group E consisted of 20 patients who had undergone an Elmslie-Trillat procedure. In Group M, also consisting of 20 patients, the Elmslie-Trillat procedure was combined with reconstruction of the MPFL. Pre and postoperative data were collected and compared. At follow-up after 2 years, the apprehension sign remained positive in 6 knees of Group E, but in none of Group M. On a stress skyline radiograph, stability was significantly better in Group M than in Group E. Based on these findings, it appears that reconstruction of the MPFL is a useful addition to the treatment of recurrent patellar dislocation and subluxation.

Adolescent↗
PubMed1989

[Transposition of the tibial tuberosity in recurrent dislocations and painful femoro-patellar syndromes. Study of a continuous series of 140 operated knees].

Surgical displacement of the tibial tuberosity has been performed in 140 cases over a 10-year period. Medial displacement with or without ventralization of the tuberosity gave excellent results in all 11 cases presenting with recurrent patellar dislocation. Anterior displacement of the tuberosity using a modified Maquet procedure was performed in 129 knees presenting with femoro-patellar pain (chondromalacia patellae, femoro-patellar osteoarthritis). Indication for surgery was intractable femoropatellar pain. Surgical technique (isolated anterior translocation or anterior and internal translocation of the tuberosity) was selected according to clinical and radiological examination. Results were very good in 50% of cases, good in 30%, poor in 20%. No patient was made worse after the procedure. The complication rate was acceptably low, due to meticulous surgical technique. The overall good results in this series are related to strict selection of patients.

Adolescent↗
PubMed1995

Cine MR imaging before and after realignment surgery for patellar maltracking -- comparison with axial radiographs.

OBJECTIVE: Comparison of motion-triggered cine magnetic resonance (MR) imaging and conventional radiographs for the assessment of operative results of patellar realignment. SUBJECTS AND METHODS: Fifteen patients with recurrent patellar dislocation or patellar subluxation were evaluated with conventional axial radiographs before and after realignment surgery by measuring the congruence angle (CA), lateral patellofemoral angle (LPFA), and lateral displacement (d). In eight patients the patellofemoral joint was additionally evaluated pre- and postoperatively with motion-triggered cine MR imaging by determining the bisect offset (BSO), lateral patellar displacement (LPD), and patellar tilt angle (PTA). RESULTS AND CONCLUSIONS: Significant differences between the pre- and postoperative measurements were found for all MR imaging parameters (BSO, LPD, PTA: p<0.01) but not for the conventional X-ray parameters (CA: p = 0.70, LPFA: p = 0.56; d: p = 0.04). Motion-triggered cine MR imaging was superior to conventional tangential radiographs for assessing the effectiveness of patellar realignment surgery.

Adolescent↗
PubMedDate not supplied

Characteristic pattern and management of intra-articular knee lesions in different pediatric age groups.

Posttraumatic hemarthrosis of the knee joint usually leads to arthroscopy. In a retrospective study we defined an age-specific spectrum of injuries and, subsequently, assigned an age-dependent diagnostic management for children up to 16 years. From January 1986 to December 1996, 1,273 patients up to 16 years of age with knee trauma presented to the emergency department. Overall, soft-tissue lesions prevailed (82%). Hemarthrosis occurred in only 18.0%. The patients were classified in three groups: group 1 (528 children younger than 10 years of age) with hemarthrosis in only 5.7% (mainly metaphyseal fractures and patellar dislocations), group 2 (207 preadolescents from 11 to 12 years of age) with hemarthrosis in 17.9% (patellar dislocations and fractures), and group 3 (538 adolescents between the age of 13 and 16 years) with hemarthrosis in 30.3% (main findings were intra-articular fractures and patellar dislocations, additionally, 16 ligamentous and two meniscal lesions). Correspondingly, physical examination, conventional radiography, and magnetic resonance imaging (most appropriate diagnostic tool for patellar dislocation) were sufficient to reveal injuries in children up to 13 years of age. Arthroscopy was predominantly justified in those older than 13 years of age, but only if it leads to therapeutic consequences.

Adolescent↗
PubMed1993

Patella baja after displacement of tibial tuberosity for patellofemoral disorders.

The change of patellar height after the displacement of tibial tuberosity and its effect on the improvement of clinical signs of knees was studied. The anterior displacement of tibial tuberosity was performed on fourteen knees and the anteromedial displacement on twenty knees with patellofemoral arthrosis of twenty-nine patients, four men and twenty-five women with the age at operation ranging from 47 to 79 years (average: 58.3). The anteromedial displacement of tibial tuberosity was performed on ten knees and medial displacement on fifteen knees with recurrent patellar dislocation (eleven knees) or patellar subluxation (fourteen knees) of twenty-four patients, two men and women with the an age range from 14 to 37, (average: 22.4). Patellar height was measured on lateral view by the Insall-Salvati method using Ligament/Patella ratio (Lt/Lp ratio). Ligament/Patella ratio of the older group with patellofemoral arthrosis was decreased significantly (p < 0.01) after surgery, from 1.10 to 0.94. The ratio of the younger group with patellar dislocation or subluxation showed no significant changes, but of seven knees with high riding patella, which ratio revealed more than 1.2 before operation, decreased significantly (p < 0.001) from 1.47 to 1.31. The postoperative patella baja had no poor effect on the improvement of clinical signs.

Adolescent↗
PubMed2001

Dislocation of the knee with lateral dislocation of the patella. A report of four cases.

In a group of 25 patients with traumatic dislocation of the knee, four, all of whom had similar ligament and medial soft-tissue injuries, also had associated lateral patellar dislocation. In all four reconstruction was delayed because of their other serious injuries. Having encountered the combination of knee dislocation and lateral patellar dislocation in 16% of our patients, we believe that it may be less rare than is commonly believed. We think that it is important to maintain a high index of suspicion of possible patellar dislocation when medial structures have been severely damaged. Early recognition and immobilisation in extension can prevent fixed lateral dislocation of the patella.

Adolescent↗
PubMed1978

Lateral dislocation of the patella following Marmor and Guepar arthroplasty of the knee.

The follow-up of 50 knees treated with the modular Marmor prosthesis and 50 with the Guepar hinge joint included tangential radiography of the femoro-patellar joint. After Marmor arthroplasty lateral patellar dislocation was found in seven knees, in six causing pain. After Guepar arthroplasty lateral patellar dislocation was found in 32 knees, but pain was present in only three. There was only a questionable correlation between pre-existing valgus deformity and postoperative lateral patellar dislocation, and an external rotation deformity of the lower leg was found in only five cases after Guepar arthroplasty. Thus, neither phenomenon could explain the high incidence of lateral patellar dislocation in the Guepar series. These dislocations must be assumed to be due to the unphysiological strain on the extensor apparatus inherent in this type of prosthesis.

Adolescent↗
PubMed1993

[Course of recurrent dislocation of the patella, patellar syndrome without dislocation and femoropatellar osteoarthritis].

The frequency of recurrent dislocation of the patella is increased by the young age of onset, the presence of patella alta and permanent subluxation of the patella. The natural history of the patellar syndrome appears to be fairly favourable in everyday activities, but discomfort is often marked in the intermediate term in sports activities. Isolated femoropatellar osteoarthritis rarely causes major functional impairment of gait. Medial or lateral femorotibial osteoarthritis occurs secondarily. Painful cases often present with subchondral anomalies of the lateral patellar facet, lateral tibial osteophytosis and patella alta.

Adolescent↗
PubMed1993

Prospective long-term results of operative treatment in primary dislocation of the patella.

Among 53 prospectively studied patients who had undergone operative treatment of primary patellar dislocation, 9 (17%) suffered recurrence within an average follow-up of 6.5 years. All the redislocations occurred in female patients. The patients with recurrence also suffered first-time patellar dislocation in their unoperated knee during the follow-up significantly more often (P < 0.01) than the patients with stable knees. Patients with redislocations were more often dissatisfied with their outcome than the stable group, mainly because of annoying anterior knee pain (P < 0.05). Preoperatively the patients with redislocation had had more pronounced pathological patellofemoral congruity (Laurin's projections) in both the operated knee (P < 0.05) and the, at the time uninjured, control knee (P < 0.05). To improve the results of operative treatment for acute patellar dislocation, surgery should be aimed at correcting the underlying pathology. In grossly and symmetrically pathological cases of patellofemoral articulation, a distal realignment procedure should be considered. Otherwise conservative treatment may be justified.

Adolescent↗
PubMed2005

Early results of one-stage knee extensor realignment and autologous osteochondral grafting.

We treated 49 patients with recurrent patellar dislocations or persistent patellar subluxations. Chondral defects were graded according to the International Cartilage Repair Society (ICRS). Thirty patients (group I) had chondral defects grade I or II, and 19 patients (group II) had chondral defects grade III or IV. All patients were treated with proximal and distal realignment of the knee extensor mechanism, but group II also had a simultaneous autologous osteochondral grafting of the chondral defect. Patients were followed for 2 years and clinically assessed using the Marshall score comparing the two groups. Apart from a slower recovery in group II, the clinical and functional results were almost the same at the final follow-up.

Adult↗
PubMed1989

The role of arthroscopy in children and adolescents.

A retrospective review of the first 5 years' experience with arthroscopy at the Adelaide Children's Hospital was conducted. Two hundred and twelve arthroscopies were performed in 192 patients. The average period of follow-up was 5.9 months. The most common arthroscopic finding was anterior cruciate ligament (ACL) injury, followed by meniscal lesions, chondromalacia patellae, patellar dislocations, and osteochondritis dissecans. There was a high rate of associated lesions with ACL tears and acute patellar dislocation. Septic arthritis responded well to arthroscopic drainage and lavage. We concluded that arthroscopy is a safe and accurate diagnostic and therapeutic tool in childhood and adolescence. Arthroscopy is recommended when a joint is too painful to allow adequate clinical examination, in hemarthroses, for ACL injury, after acute patellar dislocation, and to treat septic arthritis. There is only a 56% chance of making a correct diagnosis on clinical grounds, which contrasts with an accuracy in excess of 99% with arthroscopy.

Adolescent↗
PubMedDate not supplied

MR imaging of patellar retinacular ligament injuries.

Seventeen patients with patellar retinacular ligament injuries were evaluated with magnetic resonance (MR) imaging. MR findings were correlated with clinical, surgical, and arthroscopic findings. The injuries involved the medial retinacular ligament in 16 of 17 patients and the medial and lateral retinacular ligament in one patient. Nine of 17 patients showed MR evidence of a patellar dislocation. In these patients, a triad of findings that included focal impaction injuries involving the lateral femoral condyle, osteochondral injuries of the medial patellar facet, and injuries of the medial retinacular ligament were seen. Seven of the nine patients with patellar dislocation injuries had frank osteochondral injuries. The injured retinaculum had an indistinct, irregular appearance associated with edema and hemorrhage. The patellar dislocations were clinically unsuspected in the initial evaluation of eight of these nine patients. In eight of 17 patients, the mechanism of injury was a patellar tendon tear (n = 1) or valgus hyperextension (n = 7). In the seven patients with hyperextension injuries, three had associated meniscal and cruciate ligament tears. MR imaging can help define patellar retinacular and associated osteochondral injuries, which may be clinically useful information.

Adolescent↗