Patellar Realignment Procedures Research Articles

Modified Grammont Soft-Tissue Distal Patellar Realignment and Medial Patellofemoral Ligament Reconstruction for Patellofemoral Instability in Pediatric Patients

Patellar dislocation is a relatively common pediatric injury, which often results in recurrent patellofemoral instability. An increased tibial tubercle–trochlear groove distance predisposes to patellofemoral instability and can be corrected with a distal realignment procedure. Soft-tissue distal realignment procedures must be used in the pediatric population to avoid the risks of premature physeal closure associated with tibial tubercle osteotomies. Several soft-tissue distal realignment procedures have been described, with no consensus as to the optimal technique. When combined with medial patellofemoral ligament reconstruction, distal realignment procedures can restore patellofemoral stability through the entire flexion arc. This article describes a modification of the Grammont distal patellar realignment procedure in conjunction with medial patellofemoral ligament reconstruction for the management of pediatric patellofemoral instability.

Lateral Translation of the Patella in MPFC Reconstruction: A Biomechanical Study of Three Surgical Techniques (210)

Objectives:Recurrent patellar instability (RPI) is a common knee disorder and can lead to chronic pain and functional disability. Surgically addressing recurrent patella instability has classically focused on reconstruction of the MPFL, which has widely become the standard of care either in isolation or concomitantly with other patellar realignment procedures. Complications following MPFL reconstruction include patellar fracture, articular surface penetration, and physeal injury in skeletally immature patients. In an effort to avoid these, other surgical techniques have been described. While these alternative MPFC reconstructions have anatomical support and the theoretical potential to reduce complications, it is unknown whether differences exist in lateral patellar translation and thus their effectiveness in adequately stabilizing the patella. The purpose of this study was to investigate whether differences exist in the ability to prevent lateral patellar translation between three distinct medial patellar stabilizing surgical procedures at varying knee flexion angles.Methods:Six cadaveric knee specimens were dissected, potted, and placed in a customized jig for testing. The quadricep muscle groups were separated into three components and loaded with a total of 175 N in anatomic directions using a weighted pulley system. Lateral patellar displacement was measured at 0°, 10°, 20°, 30°, 45°, 60°, and 90° of knee flexion using a tensile testing machine with a 20 N lateral force applied to the patella. Each specimen was tested with the MPFC intact and sectioned, and after each of the three reconstruction techniques: medial patellofemoral ligament (MPFL) reconstruction, hybrid (proximal medial patellar restraints - PMPR) reconstruction, and medial quadriceps-tendon femoral (MQTFL) reconstruction. Statistical analysis used the Friedman and Wilcoxon rank sum tests due to non-normally distributed data.Results:There was significantly increased lateral patellar displacement following MPFC sectioning when compared to the intact state in early degrees of flexion (10° to 30°) (p<0.05). All three reconstruction groups adequately restored patella stability and reduced lateral patellar displacement following medial soft tissue sectioning by 42%, 41% and 33% following MPFL, Hybrid and MQTFL reconstruction, respectively, from 0° to 30° of knee flexion (p<0.05 for each reconstruction group). When compared to the native, intact medial restraints group, all three reconstruction groups demonstrated reduced patella translation at full knee extension, while the MPFL and Hybrid reconstruction groups additionally demonstrated significant reduction of patella translation at 10° of flexion as well (p<0.05). When comparing patella displacement between reconstruction groups, no significant difference was observed at any degrees of flexion between the three groups.Conclusions:This biomechanical cadaveric study demonstrates the efficacy of three different MPFC reconstruction techniques in restoring patella stability following MPFC sectioning, especially at lower knee flexion angles where the medial soft tissue restraints play a more important role. Although all three reconstruction groups demonstrated less patella translation than the native MPFL intact knee, MPFL reconstruction appears to provide the most robust patella stabilization, whereas MQTFL reconstruction may be the most forgiving construct. Future clinical studies are needed to investigate the clinical correlation of these findings.

Outcomes of Medializing Tibial Tubercle Osteotomy With Medial Reefing and Vastus Medialis Obliquus Advancement Coupled With Lateral Retinacular Z-Lengthening for Recurrent Patellar Instability.

Patella-femoral dislocations, although rare, can result in functionally limiting symptoms and limited return to prior activity levels. The purpose of this study is to report outcomes of a three-in-one patellar realignment surgery for treatment of recurrent patellar instability in a young, active duty military population. We conducted a retrospective chart review of all patients who underwent our senior author's three-in-one patellar realignment surgery for recurrent patellar instability in the setting of underlying anatomic malalignment. Our primary outcome measure was the rate of recurrent instability. Secondary outcome measures included rate of return to full unrestricted active duty military service and the functional outcome scores. A total of 13 patients with an average follow-up of 16 months were included in this study. During the follow-up period, there were no reported instability events (either dislocation or subluxation). Three (23%) patients were separated secondary to issues with their operative knee and two additional patients were no longer on active duty at time of final follow-up. Six patients had paired (pre- and postoperative) Single Assessment Numerical Evaluation scores which showed a statistically significant improvement (p < 0.05) between the median pre- and postoperative Single Assessment Numerical Evaluation scores of 45 and 85, respectively. Our study demonstrates that the described patellar realignment procedure is effective at substantially reducing and possibly eliminating the symptoms of recurrent instability and allows a modest return to unrestricted active duty.

Nail patella syndrome: une enquête sur la symptomatologie et l’évolution fonctionnelle

BackgroundPatellofemoral instability and dysfunction are frequent symptoms in nail patella syndrome (NPS). In this article, the first large series of NPS patients is presented in which these knee symptoms were assessed using validated outcome scores. Additionally, the need for surgical interventions, percentage of patients who received surgical treatment and patient reported outcomes are reported. MethodsA questionnaire-based survey was conducted in 139Dutch NPS patients. Symptoms of the knees were assessed by the Knee injury and Osteoarthritis Outcome Score (KOOS) and Kujala knee score. The questionnaire addressed whether surgical intervention was currently considered, history of past surgeries, type of surgical procedures performed and results of these procedures. ResultsResponse rate was 74%. Mean KOOS (73.04) and Kujala (74.01) scores showed a wide range and variability between patients. Patellofemoral instability was present in 48.5% of patients. Surgical intervention was currently considered by 12% of patients. Their KOOS and Kujala scores were significantly lower compared to those not considering surgery and they experienced more patellar instability. Surgery was performed on 31knees in 23patients. KOOS and Kujala scores were lower in surgically treated versus non-operated patients but no difference in patellar instability was present. An improvement in pain in 87% and in function in 30% of knees was reported after surgery. Patient satisfaction with the surgical results was 61% and 10% was dissatisfied. Patellar realignment procedures showed similar results, although persistent patellar instability was reported in 40% of patients, not different from non-operated patients. ConclusionsKnee symptoms in NPS patients vary widely, with patellar instability present in nearly half of the patients. Although surgical treatment appears unfavourable as surgically treated patients have lower KOOS and Kujala scores, the patient reported surgical results are generally good with a high patient satisfaction. Level of evidenceLevel IV.

Nail patella syndrome: Knee symptoms and surgical outcomes. A questionnaire-based survey

BackgroundPatellofemoral instability and dysfunction are frequent symptoms in Nail patella syndrome (NPS). In this article, the first large series of NPS patients is presented in which these knee symptoms were assessed using validated outcome scores. Additionally, the need for surgical interventions, percentage of patients who received surgical treatment and patient reported outcomes are reported. MethodsA questionnaire based survey was conducted in 139 Dutch NPS patients. Symptoms of the knees were assessed by the Knee injury and Osteoarthritis Outcome Score (KOOS) and Kujala knee score. The questionnaire addressed whether surgical intervention was currently considered, history of past surgeries, type of surgical procedures performed and results of these procedures. ResultsResponse rate was 74%. Mean KOOS (73.04) and Kujala (74.01) scores showed a wide range and variability between patients. Patellofemoral instability was present in 48.5% of patients. Surgical intervention was currently considered by 12% of patients. Their KOOS and Kujala scores were significantly lower compared to those not considering surgery and they experienced more patellar instability. Surgery was performed on 31 knees in 23 patients. KOOS and Kujala scores were lower in surgically treated versus nonoperated patients but no difference in patellar instability was present. An improvement in pain in 87% and in function in 30% of knees was reported after surgery. Patient satisfaction with the surgical results was 61% and 10% was dissatisfied. Patellar realignment procedures showed similar results, although persistent patellar instability was reported in 40% of patients, not different from nonoperated patients. ConclusionsKnee symptoms in NPS patients vary widely, with patellar instability present in nearly half of the patients. Although surgical treatment appears unfavourable as surgically treated patients have lower KOOS and Kujala scores, the patient reported surgical results are generally good with a high patient satisfaction. Level of EvidenceLevel IV.

Clinical and Electromyographic Results of Proximal and Distal Realignment Procedures in Young Patients With Recurrent Patellar Dislocations

Background: Until now, no study has been published about the electromyographic changes in the extensor apparatus after the Green procedure for proximal realignment in young patients with recurrent patellar dislocations. This electromyographic study was performed to analyze imbalances between the vastus medialis and vastus lateralis muscles after different patellar realignment procedures. Hypothesis: Surgical proximal realignment leads to electromyographic changes in the extensor apparatus of the knee and to imbalances between the vastus medialis and vastus lateralis muscles. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 28 knees of 25 patients, with a mean age of 15 years, were treated operatively for recurrent patellar dislocations. The mean follow-up was 6.3 years. Depending on the type of surgical intervention, the patients were assigned to 3 different groups: the patients of group 1 underwent only the Green vastus medialis obliquus (VMO) advancement, group 2 was treated with a combination of the Green proximal and the Roux-Goldthwait distal realignment, and group 3 was treated with a combination of the Green proximal realignment and an additional tubercle transfer. All patients underwent clinical, radiological, and electromyographic examinations. The muscle activities of a healthy control group without patellar dislocations were used for comparison. Results: A combination of the Green procedure and tubercle transfer led to significantly better clinical results and a lower number of redislocations (P < .05) compared with patients who underwent only the Green proximal realignment. While ascending or descending stairs, the ratio between the electromyographic activities of the vastus medialis and vastus lateralis muscles in groups 1 and 2 was significantly smaller compared with the control group (P < .02). Only the electromyograms of group 3 revealed a balanced extensor apparatus during loading with comparable activities of the vastus medialis and vastus lateralis muscles and no significant difference to the control group (P = .37). Conclusion: Our electromyographic investigations showed the importance of the vastus medialis in the pathogenesis of malalignment of the extensor mechanism. The Green VMO advancement without tibial tubercle transfer is not able to balance the activities of the vastus medialis and vastus lateralis muscles and cannot be recommended for further use.

Complex total knee arthroplasty using resection prostheses at mid-term follow-up

Complex primary or revision TKA may require the use of a resection type prosthesis to address major bone loss and soft tissue deficiencies. The aim of this retrospective study is to evaluate the clinical and radiographic outcomes of salvage knee reconstructions in a larger cohort and longer follow-up than previously reported.We therefore present the results of 66 cases treated with the Finn/OSS knee system with an average follow-up of 5years (range 2–12). Indications included 63 revision cases and three primary interventions with either massive bone loss and/or soft tissue deficiency.At final follow-up the average knee society score had significantly improved from 46 preoperatively to 73, and the function score improved from 27 to 47 points. Four cases needed to be revised: one for recurrent infection, two for aseptic loosening and one for implant breakage. Nine patients underwent minor reinterventions; including five cases with irrigation and debridement for prolonged wound drainage, two patellar realignment procedures and two extensor mechanism repairs. Two patients developed a peroneal nerve palsy. Overall implant survivorship with revision as the endpoint was 92% at 5 and 10years.We conclude that the use of a resection prosthesis in the complex primary and revision TKA leads to acceptable results, but the complication rate is relatively high.

Case Report: Quantitative MRI of Tibial Tubercle Transfer During Active Quadriceps Contraction

The evaluation of distal transfer procedures relies primarily on qualitative clinical findings. Although quantitative MRI measurements provide an objective supplement to qualitative clinical findings, an association between qualitative clinical findings and quantitative patellofemoral indices has yet to be established. A 21-year-old man presented with frequent episodes of patellar dislocation. Clinical and radiographic findings identified the patient as a candidate for realignment. MR images were obtained with the quadriceps contracted at 30° flexion and in full extension preoperatively and postoperatively. The procedure eliminated the clinical J-sign, defined as lateral movement of the patella over the lateral femoral condyle during active leg extension, which was confirmed quantitatively using established patellofemoral indices in conjunction with MRI. Movement of the patellofemoral joint is complex and dependent on many factors, including skeletal geometry, dynamic muscle action, and soft tissue restraints. Therefore, proper clinical and radiographic evaluation of patellar tracking requires observation during active quadriceps contraction. However, it is unclear whether there is any association between quantitative radiographic indices and qualitative clinical assessment during active quadriceps contraction. We believe objective measurements are valuable in determining the radiographic assessment of patellar realignment procedures. Lateral patellar edge appears to quantify the clinical J-sign. The association between radiographic medialization of the patella and clinical improvement postoperatively in this patient warrants additional investigation in a larger group of patients with longer followup.

Concepts for assessment and treatment of anterior knee pain related to altered spinal and pelvic biomechanics: A case report

Anterior knee pain is a musculoskeletal condition that is associated with symptoms including pain around the region of the patellofemoral articulation and can be aggravated by activities that increase load through the patellofemoral joint (McConnell, 1986). Differentiation of the cause of anterior knee pain based on location of pain is difficult since many conditions are characterized by pain around the patella. Furthermore, aggravating activities including squatting, kneeling, sitting and ascending or descending stairs are similar across numerous conditions. Most clinical practice draws on evidencebased local interventions including quadriceps muscle re-education and patellar realignment procedures including taping and stretching in an attempt to optimize the biomechanics of the patellofemoral joint (Crossley et al., 2001; Cowan et al., 2001; Hinman et al., 2003). In the reported case of a patient with anterior knee pain, improvements in knee pain and range of motion during squatting were found immediately following mobilization of the thoracic spine and the lumbosacral junction. It is the purpose of this case report to explore reasons behind this improvement and to discuss the implications for assessment and management.

Recent concepts in patellofemoral instability

Purpose of review: Recent patellofemoral literature on biomechanical and anatomical analyses, imaging studies, acute and chronic instability treatment, and patellar realignment procedures will be reviewed. Recent findings: A recent epidemiological study found women aged 10–17 years to be most predisposed to acute and recurrent patellar instability. Instability is experienced most readily at 20° of flexion where vastus medialis obliquus tension is also the least. A decreased Q-angle, however, improved resistance to lateral patellar tracking more than strengthening of the vastus medialis obliquus. Although conservative is still recommended for treatment primary dislocations, chronic instability is better treated with surgery. Mini-open medial reefing with lateral release, vastus lateralis tendon release, and medial patellofemoral ligament reconstruction have all showed promising results. Cadaveric studies facilitated the improved outcomes by helping us determine the isometric point of the medial patellofemoral ligament. Distal realignment procedures such as the Elmslie–Trillat and modified Roux–Goldthwait procedure have also improved outcomes in the proper population. Interestingly, patients with trochlear dysplasia benefited from proximal and distal realignment procedures more conclusively than by undergoing trochleoplasty. Summary: Understanding the anatomy and biomechanics of the patellofemoral joint will guide future testing and treatment methods. Patellar realignment procedures are successful in managing recurrent instability; arthrosis and pain, however, are less controlled.

An all-arthroscopic soft-tissue balancing technique for lateral patellar instability

Patellar realignment procedures for lateral patellar instability often involve open approaches to imbricate the medial soft tissues. We present a technique to balance the soft tissues to correct lateral patellar instability that is performed entirely arthroscopically. A retinacular release is performed laterally and the soft tissues are imbricated medially using arthroscopic suture passing and knot tying techniques.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 5 (May-June), 2001: pp 555–557

Autologous chondrocyte implantation

Autologous chondrocyte implantation (ACI) has been performed in more than 4,500 patients and, when appropriately indicated, provides durable hyaline-like repair tissue with consistent clinical results. ACI is primarily indicated for full-thickness articular cartilage injuries of the femoral condyles and trochlea. Emerging evidence suggests that it may also have a role in the treatment of patellar defects. The success of ACI is in part attributed to its ability to resolve the limitations of other techniques that are at best palliative or reparative with limited capacity to restore hyaline or hyaline-like tissue. Lesions of the femoral condyles and trochlea can be expected to respond favorably to treatment in greater than 85% of all patients, both clinically and subjectively with follow-up at 2 to 9 years. Patients with multiple lesions or lesions involving the patella have not responded as well, but up to 70% still show improvement with more consistent results if ACI is accompanied by a patellar realignment procedure when indicated.

Double modified Hauser procedure: a long-term follow-up

A long-term follow-up of 20 patients (23 knees) who had undergone the double modified Hauser (DMH) procedure was conducted. This procedure, a modification of a previously reported distal patellar realignment procedure 1, consists of medial and proximal implantation of the tibial tubercle to correct abnormal tracking with simultaneous anterior advancement (Maquet principle) to reduce contact pressures. All but two patients had undergone failed surgeries in the past and required operative intervention because of repeated patellar dislocations with severe anterior knee pain or, in five cases, severe pain due to advanced patellofemoral arthrosis. At an average follow-up of 11.6 years, 16 20 patients were satisfied with the result, two were unsure and two were dissatisfied. Recurrent dislocations occurred in four patients. At rest, 11 23 knees were occasionally painful, while 20 knees were occasionally painful when walking. Of 20 knees X-rayed, degenerative changes were found in 12, of which five had undergone patellectomy for intractable anterior knee pain. While this procedure is not recommended as a primary operation to correct tracking, the authors feel it offers theoretical advantages over the Maquet procedure for salvage purposes when arthroscopic lateral release has failed.

Posterior Dislocation of Total Knee Arthroplasty

Posterior dislocation of the prosthesis after total knee arthroplasty is an infrequent but serious complication. Seven patients with this complication were treated from January 1985 until October 1989. Five of the seven dislocations occurred in primary total knee arthroplasties and two occurred after revision arthroplasty. Limb alignment before arthroplasty, when it could be determined, was valgus in all patients, averaging 25 degrees. In each case there was an identifiable problem with the knee extensor mechanism: five had patellar dislocations, one a patellar tendon rupture, and one a patellar fracture. In three of the posterior dislocations, there was also an imbalance of the flexion and extension gaps with excessive laxity of the ligaments in flexion. Treatment was individualized. In two patients, the knee was reduced closed and the patella subsequently tracked so that no reoperation was necessary. One ruptured patellar tendon could not be repaired in a 94-year-old patient with cardiac disease. A cylinder cast was applied with poor results. Operative intervention was required in four patients, one of whom required only a patellar realignment procedure. The three other patients required component revision procedures, however, in addition to patellar realignment procedures. In these three patients, laxity of the knee in flexion was so severe that posterior instability could not be corrected merely by patellar relocation. At a follow-up examination (average, 21 months postoperatively), all six patients who were treated as recommended had good results with no further dislocations, with the exception of the one patient with a patellar tendon rupture.

Patellar Tendon Rupture After Total Knee Arthroplasty

Between 1973 and 1985, 18 knees in 17 patients were treated for rupture of the patellar tendon after total knee arthroplasty (TKA), accounting for 0.17% of the TKAs performed at the authors' institution during the same interval. Follow-up study was from two and one-half years to four years. Four ruptures occurred in patients who had had a distal patellar realignment procedure, and one occurred after knee manipulation. Only two xenograft reconstructions and two of four staple fixation procedures were successful. After treatment of the patellar tendon rupture, four knees developed deep infection. Avoidance of this complication seems paramount because the results of treatment are discouraging. Patients at high risk at the time of the initial TKA seem to be those with limited preoperative motion in whom surgical exposure is difficult.

An Arthroscopic Method for Lateral Release of the Subluxating or Dislocating Patella

Arthroscopically controlled lateral release for subluxating and dislocating patellae was reviewed in 93 knees (79 patients) at an average of 48.7 months follow-up. Of the patients, 92 % reported significant subjective improvement. Eighty-nine per cent of males and 69% of females were rated good or excellent by objective criteria. Failure to maintain good quadriceps muscle strength was the major reason for fair and poor results. Of 14 knees with dislocations, none had a recurrence after surgery. Patellar shaving was not done in any of the knees. The results of lateral release did not correlate with the severity of chondromalacia patellae. Complications and morbidity were significantly reduced by this outpatient procedure. Experience in endoscopic techniques is an important prerequisite. In the properly selected and motivated patient, this procedure offers an effective alternative to major patellar realignment procedures.

Results of Patellar Realignment in Patients Older than Thirty

A retrospective study of patellar realignment procedures was performed on patients over the age of 30 years, with a mean follow-up of 32 months on 16 operated-on-knees in 14 patients. The best results were achieved in patients with preoperative apprehension and compression signs, as well as a typical history for patellar subluxation. when these signs were absent after operation, the result was better than seen in patients whose clinical signs persisted. There was no correlation of results with the grade of chondromalacia noted at surgery. Good or excellent results were achieved in about 75% of the patients. An accurate preoperative diagnosis in the selection of operative candidates is imperative.