Lateral release of the patella: indications and contraindications

Selective hemiepiphyseodesis for patellar instability with associated genu valgum

BACKGROUND/AIMS

Patellar instability limits activity and promotes arthritis. Correcting genu valgum with selective hemiepiphyseodesis can treat patellar instability.

METHODS

We retrospectively reviewed 26 knees with patellar instability and associated genu valgum that underwent hemiepiphyseodesis.

RESULTS

Average anatomic lateral distal femoral angle (aLDFA) significantly corrected. Symptoms improved in all patients. All competitive athletes returned to sports. One complication occurred.

CONCLUSIONS

In genu valgum, the patella seeks an abnormal mechanical axis, resulting in patellar instability. By correcting the mechanical axis with hemiepiphyseodesis, patellar instability symptoms improve and patients return to sports. Complications are rare. Selective hemiepiphyseodesis is recommended when treating patellar instability with associated genu valgum.

Patellar Tendon Rupture after Lateral Release without Predisposing Systemic Disease or Steroid Use

Arthroscopic technique for lateral release is the most widely used procedure for the correction of recurrent dislocations of the patella. In the relevant literature, several complications of lateral release are described, but the spontaneous patellar tendon rupture has never been suggested as a possible complication of this surgical procedure. Patellar tendon rupture is a rather infrequent and often unilateral lesion. Nevertheless, in case of systemic diseases (LES, rheumatoid arthritis, and chronic renal insufficiency) that can weaken collagen structures, bilateral patellar tendon ruptures are described. We report a case of a 24-year-old girl with spontaneous rupture of patellar tendon who, at the age of 16, underwent an arthroscopic lateral release for recurrent dislocation of the patella. This is the first case of described spontaneous patellar tendon rupture that occurred some years after an arthroscopic lateral release.

Lateral patellar facetectomy and medial reefing in patients with lateral facet syndrome after patellar-retaining total knee arthroplasty

We analyzed clinical outcomes of partial lateral patellar facetectomy and medial reefing in patients with lateral patellar facet syndrome with painful patellar-retaining total knee arthroplasty. 34 patients were followed for a mean of 40 months. All 34 patients were matched with those having secondary patellar resurfacing without facetectomy. Both groups experienced significant pain relief and range of motion improvement. The facetectomy group had higher Kujala scores than those in patellar resurfacing group. Patients with facetectomy had significantly less pain postoperatively. There were significant differences in postoperative lateral patellar tilt and congruency angle in both groups. The mid-term results for LPF with medial reefing are promising to resolve pain in patients with lateral patellar facet syndrome in patellar-retaining TKA. Therapeutic level III (retrospective comparative study).

Quantitative stress radiography of the patella and evaluation of patellar laxity before and after lateral release for recurrent dislocation patella

PURPOSE

The aims of the present controlled clinical study were to (1) compare patella laxity determined in the outpatient clinic with that in anaesthetized patients and (2) evaluate patella laxity before and after lateral release.

METHOD

The study evaluated data on 33 knees from 33 patients (average age 19.7 years) between 2007 and 2011. All patients were diagnosed with recurrent dislocation of the patella. Patellar stability was evaluated in each patient thrice: patellas were first imaged in the outpatient clinic prior to surgery at 45° knee flexion with 20 N stress from the medial to lateral side and from the lateral to medial side; then, at the time of surgery, patella stress images were obtained in the same manner before and after the lateral release procedure. Radiological assessments were performed using the medial stress shift ratio (MSSR) and lateral stress shift ratio (LSSR).

RESULTS

There were no significant differences in the LSSR and MSSR before surgery (outpatient data) and in anaesthetized patients before the lateral release procedure. Furthermore, there was no significant difference in MSSR at the time of surgery before and after the lateral release procedure. However, LSSR increased significantly after the lateral release procedure.

CONCLUSION

The results of the present study suggest that quantitative patella stress radiography in the outpatient clinic is useful when it comes to investigating laxity of the patella, and that lateral release significantly increases lateral, but not medial, laxity in patients with recurrent patellar dislocation.

LEVEL OF EVIDENCE

IV.

Lower extremity thrust and non-thrust joint mobilization for patellofemoral pain syndrome: a case report

A 40-year old female presented to physical therapy with a one-year history of insidious right anteromedial and anterolateral knee pain. Additionally, the patient had a history of multiple lateral ankle sprains bilaterally, the last sprain occurring on the right ankle 1 year prior to the onset of knee pain. The patient was evaluated and given a physical therapy diagnosis of patellofemoral pain syndrome (PFPS), with associated talocrural and tibiofemoral joint hypomobility limiting ankle dorsiflexion and knee extension, respectively. Treatment included a high-velocity low amplitude thrust manipulation to the talocrural joint, which helped restore normal ankle dorsiflexion range of motion. The patient also received tibiofemoral joint non-thrust manual therapy to regain normal knee extension mobility prior to implementing further functional progression exercises to her home program (HEP). This case report highlights the importance of a detailed evaluation of knee and ankle joint mobility in patients presenting with anterior knee pain. Further, manual physical therapy to the lower extremity was found to be successful in restoring normal movement patterns and pain-free function in a patient with chronic anterior knee pain.

Success of torsional correction surgery after failed surgeries for patellofemoral pain and instability

Torsional deformities of the femur and/or tibia often go unrecognized in adolescents and adults who present with anterior knee pain, and patellar maltracking or instability. While open and arthroscopic surgical techniques have evolved to address these problems, unrecognized torsion may compromise the outcomes of these procedures. We collected a group of 16 consecutive patients (23 knees), with mean age of 17, who had undergone knee surgery before torsion was recognized and subsequently treated by means of rotational osteotomy of the tibia and/or femur. By follow-up questionnaire, we sought to determine the role of rotational correction at mean 59-month follow-up. We reasoned that, by correcting torsional alignment, we might be able to optimize long-term outcomes and avert repeated knee surgery. Knee pain was significantly improved after torsional treatment (mean 8.6 pre-op vs. 3.3 post-op, p < 0.001), while 70 % of patients did have some continued knee pain postoperatively. Only 43 % of patients had continued patellar instability, and 57 % could trust their knee after surgery. Activity level remained the same or increased in 78 % of patients after torsional treatment. Excluding planned rod removal, subsequent knee surgery for continued anterior knee pain was undertaken on only 3 knees in 2 patients. We believe that malrotation of the lower limb not only raises the propensity for anterior knee symptoms, but is also a under-recognized etiology in the failure of surgeries for anterior knee pain and patellar instability. Addressing rotational abnormalities in the index surgery yields better clinical outcomes than osteotomies performed after other prior knee surgeries.

Treatment options for patellofemoral instability in sports traumatology

Patellofemoral instability not only involves lateral patellar dislocation, patellar mal-tracking or subluxation but can also cause a limiting disability for sports activities. Its underlying causes are known as morphological anomalies of the patellofemoral joint or the mechanical axis, femorotibial malrotation, variants of the knee extensor apparatus, and ligamentous insufficiencies often accompanied by poor proprioception. Athletes with such predisposing factors are either suffering from unspecific anterior knee pain or from slightly traumatic or recurrent lateral patellar dislocation Treatment options of patellar instability are vast, and need to be tailored individually depending on the athlete’s history, age, complaints and physical demands. Different conservative and surgical treatment options are reviewed and discussed, especially limited expectations after surgery.

Patella instability: building bridges across the ocean a historic review

The diagnosis of and treatment for musculoskeletal disease and injuries have seen an explosion of new knowledge. More precise imaging, correlative injury anatomy, more focused physical examination features, among others, have led this upsurge of current insight. Crucial to this knowledge revolution is the expansion of international knowledge, which is aided by an adoption of a universal scientific language, electronic transfer of information, and personal communication of surgeons and scientists across national boundaries. One area where this is particularly evident is in our knowledge and treatment for patellofemoral disorders. This article will review the developments in the management of patellar dislocations by tracing their historical roots. This is not meant to be a comprehensive review, but rather to give current readers a "historical memory" upon which to judge and interpret our present-day bridge of knowledge. Level of evidence V.

Incidence and radiologic predictor of postoperative patellar instability after Fulkerson procedure of the tibial tuberosity for recurrent patellar dislocation

PURPOSE

Excellent results of anteromedialization of the tibial tuberosity for recurrent patellar dislocation have been reported; however, the contribution of the preoperative anatomic factors to postoperative patellar instability has not been well established. The purpose of this study was to investigate the mid-term results and the incidence of postoperative patellar instability after Fulkerson procedure for recurrent patella dislocation, and to determine the radiologic predictor of the postoperative patellar instability.

METHODS

Sixty-two knees of 41 patients underwent Fulkerson procedure with or without lateral retinacular release for recurrent patellar dislocation and were followed-up for 85-155 months. Predisposing anatomic factors for recurrent patellar dislocation were evaluated preoperatively, including valgus knee alignment (femorotibial angle), patella alta (Insall-Salvati ratio), trochlear dysplasia (trochlear depth), lateral patellar displacement (congruence angle) and lateral malposition of the tibial tuberosity (tibial tuberosity-trochlear groove distance). The relationship between the measurements of anatomic factors and postoperative patellar instability, which was defined by the patellar re-dislocation or residual apprehension after surgery, was analyzed.

RESULTS

The Fulkerson score and the Kujala score were significantly improved from the median of 65 (35-80) points and 68 (36-82) points preoperatively to 95 (60-100) points and 92 (57-100) points at the final follow-up, respectively. Three knees (4.8%) experienced postoperative patellar re-dislocation and 4 knees (6.5%) showed the positive apprehension sign at the final follow-up. The statistical analysis showed that the postoperative patellar instability correlated with only patella alta.

CONCLUSION

Patella alta was the only predictor of postoperative patellar instability after Fulkerson procedure. These results indicated that isolated Fulkerson procedure should not be indicated for recurrent patellar dislocation with severe patella alta.

LEVEL OF EVIDENCE

Case-control study, Level III.

Complications in brief: Arthroscopic lateral release

Arthroscopic lateral release refers to an arthroscopic procedure that incises the lateral stabilizing structures of the patella, in particular, the lateral retinaculum. The lateral retinaculum attaches the lateral patella to the lateral femoral epicondyle, the iliotibial band, and the anterolateral tibia. Arthroscopic lateral release rarely is performed as an isolated procedure and rather is generally performed in combination with medially based stabilization procedures to more effectively allow for medial realignment. The procedure is relatively simple and straightforward, but, if not done for the appropriate indications or if done technically poorly, either it will not achieve the desired result or it may result in additional pain, instability, and weakness. This In Brief article provides an overview of potential complications of lateral release.

The operative management of patella malalignment

Management of patellofemoral joint pathology is challenging as a result of the unique and complex organization of static forces and dynamic factors contributing to its functional capacity. Anterior knee pain is a common musculoskeletal complaint seen daily in the practices of primary care physicians, rheumatologists, and orthopedic surgeons. The key to successful treatment lies not only in the correct diagnosis of a chondral defect, but more importantly, in the accurate identification of associated pathomechanical factors. Appreciating the pathoanatomic basis of the disease and addressing imbalances and anatomical abnormalities should guide treatment.Despite the complexity of the interplay of various components it is essential to attempt to describe patellar malalignement as a clinical entity in order to proceed with appropriate surgical management and successful outcomes. The goals of patellofemoral re- alignment surgery should be to create both a stable environment for optimal extensor mechanism performance and an appropriate load transmission for optimal cartilage wear and joint loading. In the context of this article we will review the operative management of patellofemoral malalignment; the indications for surgery, the different techniques available and the evidence regarding their effectiveness.A large number of procedures have been employed and they have all undergone various modifications over the course of the years. The majority of publications are retrospective series in poorly defined population groups. There are significant methodological inconsistencies and as a result there is lack of strong evidence base for the majority of these procedures.

Open lateral patellar retinacular lengthening versus open retinacular release in lateral patellar hypercompression syndrome: a prospective double-blinded comparative study on complications and outcome

PURPOSE

To compare complication rates and outcome of open lateral retinacular (LR) lengthening and open LR release in the treatment of lateral patellar hypercompression syndrome (LPHS).

METHODS

In a prospective double-blinded study, 28 patients (mean age, 48 years; 21 women and 7 men) received either LR release (14 patients) or LR lengthening (14 patients) in alternating fashion over the same lateral parapatellar skin incision for LPHS (blinding of patients to surgical procedure [i.e., single blinding]). Strict inclusion criteria (retinacular pain, tight retinaculum, decreased patellar mobility) were used to exclude other reasons for anterior knee pain (patellar instability, leg malalignment or maltorsion, trochlear dysplasia, patella alta). The surgeon and postsurgical rehabilitation were the same. Preoperatively and at 3, 6, 12, and 24 months postoperatively, complications, muscle atrophy, and Kujala patellofemoral outcome score were documented by examiners blinded to the surgical procedure (double blinding). All patients completed 2 years of follow-up.

RESULTS

The results of 2 years of follow-up showed that recurrence of LPHS, as indicated by the patellar tilt test and decreased medial patellar glide test, developed in 2 cases after LR release and 1 case after LR lengthening (P > .999). Medial patellar subluxation, as indicated by the gravitation-subluxation test and increased medial patellar glide test, developed in 5 cases after LR release and no case after LR lengthening (P = .041). Quadriceps atrophy, as indicated by the mean circumference difference compared with the healthy contralateral side, was significantly higher (P = .001) in the LR release group (1.8 cm) than in the LR lengthening group (0.2 cm). The mean Kujala score was significantly lower (P = .035) in the LR release group (77.2 points) than in the LR lengthening group (88.4 points).

CONCLUSIONS

In this prospective double-blinded study, retinacular lengthening showed less medial instability, less quadriceps atrophy, and a better clinical outcome at 2 years compared with retinacular release. We believe that this may be explained by the controlled preservation of the lateral patellar muscle-capsuloligamentous continuity after retinacular lengthening.

LEVEL OF EVIDENCE

Level II, prospective double-blinded comparative study.

Analysis of failed surgery for patellar instability in children with open growth plates

PURPOSE

Many surgical procedures have been proposed to treat recurrent patellar dislocation in children. In recent years, a more tailored approach considering the underlying pathology has been advocated. The aim of the study was to analyze a group of patients with recurrent patellofemoral instability after unsuccessful operative stabilization (Roux-Goldthwait procedure, lateral release, medial reefing or in combination) in childhood and adolescence.

METHODS

A total of 37 children and adolescents with recurrent patellofemoral instability despite previous surgery were analyzed retrospectively. Radiographic examination included AP and lateral views to assess patella alta and limb alignment. MRI was performed to evaluate trochlear dysplasia and tibial tubercle-trochlear groove (TTTG) distance. As a control group, 23 age- and sex-matched adolescents that were treated with a favorable outcome after medial reefing alone or combined with a Roux-Goldthwait procedure were analyzed.

RESULTS

Severe trochlear dysplasia (type B-D according to Dejour) as detected on MRI scans was found significantly more often in the study group (89%) than in the control group (21%). No statistical difference of patellar height ratio (Insall-Salvati index) and TTTG distance between the two groups could be found.

CONCLUSION

Of the measured parameters, only the incidence of trochlear dysplasia was increased. Trochlear dysplasia therefore seems to be a major risk factor for failure of operative stabilization of recurrent patellofemoral instability in children and adolescents. The results in children are in consensus with the literature in adults that a more tailored operative therapy including reconstruction of the MPFL and trochleaplasty has to be considered.

LEVEL OF EVIDENCE

Retrospective study, Level III.

Effects of medial patellofemoral ligament reconstruction on patellar tracking

PURPOSE

Medial patellofemoral ligament (MPFL) reconstruction has been performed to treat recurrent patellar dislocation. However, the effects on patellar tracking have not been well documented, particularly in patients. The purpose of this study is to compare patellar tracking pattern and chondral status at MPFL reconstruction with those at second-look arthroscopy.

METHODS

Between 1999 and 2008, 71 patients with recurrent patellar dislocation underwent MPFL reconstruction using a double-looped semitendinosus tendon. Of these, 25 knees in 24 patients underwent second-look arthroscopy (at 6-26 months after initial surgery), forming the subject for the present study. No other surgical procedures such as tibial tuberosity transfer, lateral release, or osteotomy were performed in any patients. To assess the patellar tracking pattern, the position of the patella on femoral groove was evaluated arthroscopically during passive knee motion through lateral suprapatellar portal.

RESULTS

Before MPFL reconstruction, the patella in all patients was shifted laterally throughout the entire range of knee motion. Immediately after MPFL reconstruction, patellar malalignment was corrected in all cases. On second-look arthroscopy, two different patellar tracking patterns were observed. In 9 knees, the patella was located on the center of the femoral groove throughout the range of motion. Meanwhile, in the remaining 16 knees, the patella was shifted laterally at knee extension and migrated to the center of femoral groove with increased knee flexion. No significant deteriorations in chondral status were seen on second-look arthroscopy.

CONCLUSION

The present study revealed that not all improved patellar trackings after MPFL reconstruction remained intact at follow-up. Chondral status in patellofemoral joint was not aggravated by MPFL reconstruction.

LEVEL OF EVIDENCE

Therapeutic studies, Level IV.

Open lateral retinacular closure surgery for treatment of anterolateral knee pain and disability after arthroscopic lateral retinacular release

BACKGROUND

Although lateral retinacular release (LR) surgery has historically been one of the most commonly used arthroscopic procedures for the treatment of patellar instability and anterior knee pain, it may be associated with complications and poor functional outcome measures.

PURPOSE

To examine the clinical efficacy of open lateral retinacular closure (LRC), a novel but technically simple procedure in the treatment of disabling anterolateral knee pain, tenderness, and positive medial patellar apprehension testing in patients who have undergone prior arthroscopic LR surgery.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

The records of 22 patients who had previously undergone an arthroscopic LR and underwent a diagnostic arthroscopy and LRC were reviewed. Physical examination findings and symptoms after prior LR surgery, duration between LR and LRC surgeries, and arthroscopic findings immediately before LRC were analyzed. Preoperative and postoperative Lysholm knee scores and activity levels were compared, and subjective satisfaction ratings assessed.

RESULTS

Average follow-up after LRC was 3.2 years. Mean preoperative Lysholm knee score was 46.5 (range, 25-90), which improved postoperatively to a mean score of 86 (range, 48-100). Fourteen percent of patients subjectively rated their preoperative function as fair and 86% as poor. Postoperatively, 82% rated themselves as good or excellent and 18% as fair, with all patients improving from the LRC procedure. All patients stated that they would have the procedure again for the same problem.

CONCLUSION

Open LRC provides significant pain relief and improvement in functional knee outcome scores in patients with persistent pain and tenderness at the site of a previous lateral release and a positive medial patellar apprehension test. Lateral release procedures should be considered with caution. For patients with anterolateral knee pain and symptoms of medial patellar instability after lateral release, LRC may provide symptomatic relief and functional improvement.

Medial patellofemoral ligament reconstruction with a divergent patellar transverse 2-tunnel technique

BACKGROUND

The medial patellofemoral ligament (MPFL) is the primary passive restraint to lateral patellar dislocation and there is increasing awareness of its role in recurrent lateral patellar instability.

PURPOSE

This study was conducted to prospectively analyze the functional results of a modified MPFL reconstruction technique in recurrent patellar dislocation.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Forty-eight patients (51 knees) with at least 3 episodes of lateral patellar dislocation who had been treated with a 6-month rehabilitation protocol were included in this study. All patients practiced sports regularly. Reconstruction was with a semitendinosus tendon using a divergent 2-tunnel technique. Outcome was evaluated with the Kujala, Larsen, modified Lysholm, and Fulkerson outcome scores. Patient satisfaction with range of motion, pain, and sporting activities was also assessed.

RESULTS

Three patients were lost at the final follow-up, giving a follow-up rate of 94%. The mean follow-up was 33 months. There was no patella dislocation postoperatively. The mean Kujala score improved significantly (P < .01) from 56.7 ± 17.7 (2 × standard deviation) preoperatively to 86.8 ± 14.4 postoperatively. The mean Larsen score improved significantly (P < .01) from 12.4 ± 3.2 to 17.1 ± 2.7. The mean Fulkerson score improved significantly (P < .01) from 59.2 ± 21.8 to 90.1 ± 14. The mean modified Lysholm score improved significantly (P < .01) from 57.6 ± 19.6 to 88.1 ± 16.2. Sixty-four percent of patients returned to the same type of sport at the same level, 16% reduced the level or type of sport for reasons unrelated to the surgery, while 20% reduced the level of sport or changed it for reasons related to surgery. Eighty-seven percent were either satisfied or very satisfied with the pain relief achieved. The patellar tilt decreased significantly from a preoperative mean of 11.1° to 8.9° at the last follow-up (P = .02). The mean preoperative Insall-Salvati ratio of 1.1 decreased to 1.06, although the change was not significant (P = .1).

CONCLUSION

The results of modified MPFL reconstructions are encouraging, with minimal risks of redislocation and an overall patient satisfaction rate of over 80%. These early and medium-term results are comparable with those of other MPFL reconstruction techniques reported in the literature.

Clinical outcomes of medial patellofemoral ligament repair in recurrent (chronic) lateral patella dislocations

PURPOSE

The specific aim of this project was to review a homogenous group of patients who had chosen to undergo medial patellofemoral ligament (MPFL) repair to stabilize their patella after repeat (chronic) patellofemoral dislocations and to record the success of this procedure in stabilizing the patella against further lateral dislocations.

METHODS

This is a retrospective study of 55 knees in 48 patients who underwent a repair of the medial patellofemoral ligament by a single surgeon over a 4-year period. The endpoint of the study was a documented patellofemoral dislocation or a minimum 2-year follow-up.

RESULTS

Fifty-five knees in 48 patients underwent a MPFL repair/reattachment. Patella alta, as defined by the Insall-Salvati (I/S) ratio, was within normal limits in 6 (14%). The I/S ratio was greater than 1.2 in 38 patients (86%) and greater than 1.4 in 23 patients (52%). Trochlear dysplasia as defined by a positive crossing sign on a true lateral radiograph and/or a sulcus angle on axial view of greater than 145 was present in 45/47 (96%). Successful management of the knee as defined by no further patella dislocation occurred in 22 knees. Nineteen knees sustained a redislocation event (46%).

CONCLUSIONS

The surgical procedure of operative repair (reattachment) of the MPFL to its femoral attachment had a significantly high rate of failure in this patient group of chronic (repeat) lateral patellar dislocators.

Dual tunnel medial patellofemoral ligament reconstruction for patients with patellar dislocation using a semitendinosus tendon autograft

The purpose of this study was to describe a safer and more anatomical technique of MPFL reconstruction and to report the short-term results. The subjects included 20 patients with patellar dislocation with a mean age of 23. The operation was performed using a double-looped autogenous semitendinosus tendon graft. Two small bone tunnels were made at the medial edge of the patella, mimicking the wide patellar insertion of the MPFL and a bone tunnel was made at the femoral insertion site. The free ends of the graft attached to the patella and the loop end was fixed to the femoral side. Five patients were available for follow-up interviews by telephone and the remaining 15 were directly examined by physical examination and radiographic evaluation at 2 years or longer postoperatively. The average follow-up period was 30 months. Re-dislocation or patellar fracture was not seen in any patients. The average Kujala's score was 96 with a range from 84 to 100. Six patients were classified as excellent and 14 as good, according to the Crosby and Insall grading system. Radiographically, narrowing of the patellofemoral joint space was observed in 2 cases with previous osteochondral fracture out of those who were directly examined. The dual tunnel MPFL reconstruction produces favorable results in subjective and functional assessment of outcome without complications.

Patellar subluxation at terminal knee extension: isolated deficiency of the medial patellomeniscal ligament

BACKGROUND

The medial patellomeniscal ligament has been determined in vitro to be the only substantial distal-medial restraint to lateral patellar displacement. The purpose of this study of prospectively collected data was to determine if isolated deficiency of the medial patellomeniscal ligament, resulting in excessive lateral patellar translation and associated symptoms, could be identified. We hypothesized that, if symptoms were associated with isolated deficiency of that ligament, the laxity and symptoms should resolve after plication of that ligament alone.

METHODS

Testing for lateral patellar displacement in the extended knee by exertion of force through the distal patellar attachment of the medial patellomeniscal ligament was performed on 745 patients with patellofemoral syndromes during a twenty-eight-month period. In addition, the ability to recognize pathologically increased lateral patellar translation preoperatively with use of such testing was compared with the ability to recognize increased lateral translation with testing in 439 patients undergoing arthroscopy under anesthesia during that period for any reason. Preoperative symptoms and impairment in knees with isolated deficiency of the medial patellomeniscal ligament were documented and compared with the postoperative results.

RESULTS

Isolated medial patellomeniscal ligament deficiency was identified with testing under anesthesia in twenty-three of the 439 knees undergoing arthroscopy for any reason, and twenty of those twenty-three cases had been detected preoperatively with use of lateral patellar displacement testing. Isolated medial patellomeniscal ligament plication was performed in these twenty-three cases, and follow-up data at a mean of 30.8 months were available for twenty-one of the cases. The mean International Knee Documentation Committee subjective score increased from 38.9 preoperatively to 84.6 postoperatively, and recurrent symptomatic pathological lateral patellar translation was present in only one patient.

CONCLUSIONS

Isolated deficiency of the medial patellomeniscal ligament can be detected by physical examination. Restoration of the normal length of the ligament by plication can lead to resolution of detectable patellar subluxation and its associated symptoms.

Anatomical transverse patella double tunnel reconstruction of medial patellofemoral ligament with a hamstring tendon autograft for recurrent patellar dislocation

INTRODUCTION

The purpose of this study was to describe our transverse patella double tunnel technique to reconstruct the medial patellofemoral ligament (MPFL) with a hamstring tendon autograft in patients who suffered recurrent dislocation of the patella, and to evaluate the intermediate-term outcomes of reconstruction treatment.

MATERIALS AND METHODS

Fifty-nine consecutive knees (52 patients) with recurrent dislocation of the patella without marked predisposing anatomic abnormalities and radiographically documented moderate/severe osteochondral lesions were included in the study. Outcomes were assessed with physical and radiographic examination, the Kujala and the modified Cincinnati scores preoperatively and postoperatively at 3, 6, 12, 36, 60 and 84 months.

RESULTS

There were 19 male and 33 female patients with up to 7.1-year follow-up (mean 5.7 years). The mean age was 24.3 years. A comparison of preoperative scores with those obtained at most recent follow-up revealed a significant improvement for all outcomes measured: range of motion (30 ± 2° vs. 125 ± 5°, P < 0.01), the mean Kujala scores (41.4 vs. 82.6, P < 0.001), the mean modified Cincinnati scores (50.6 vs. 88.7, P < 0.01), the mean congruence angle (12.2° vs. -2.4°, P < 0.01) and the mean tilt angle (11.4° vs. 8.4°, P < 0.05). No recurrent episodes of dislocation or subluxation were postoperatively reported, although there were seven knees with an occasional unstable feeling without redislocation.

CONCLUSIONS

MPFL reconstruction with the double-transverse tunnels technique is safe and effective in patients of all ages, without marked predisposing anatomic abnormalities and moderate/severe osteochondral lesions, who suffered recurrent dislocation of the patella.

The biomechanics of medial patellofemoral ligament repair followed by lateral retinacular release

BACKGROUND

Repair of the medial patellofemoral ligament (MPFL) for acute patellar instability has recently become popular, with good clinical success rates reported in the literature. Usually, a lateral retinacular release (LRR) is added to the medial repair in an effort to "rebalance" the patella. In the native knee, however, isolated LRR reduces the force required to displace the patella laterally and may be an undesirable component of instability surgery.

HYPOTHESIS

The authors' hypothesis was that LRR, when performed after MPFL repair, would reduce the force required to displace the patella laterally.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eight fresh-frozen human cadaveric knees were prepared as a model for acute patellar dislocation by transecting the MPFL at its patellar attachment. The knees were sequentially tested in the native (control), cut MPFL, repaired MPFL, and repaired MPFL with LRR conditions. Each knee was mounted and tested on an MTS machine that measured the amount of force required to displace the patella 1 cm laterally. Testing was done at 0 degrees , 15 degrees , 30 degrees , 45 degrees , and 60 degrees of knee flexion.

RESULTS

Cutting the MPFL reduced the force required to displace the patella 1 cm laterally by 14% to 22% compared with the native knee. Repair of the ligament restored the ability of the patella to resist lateral force. Adding a lateral release to the repair reduced the force required to displace the patella 1 cm by 7% to 11% compared with the MPFL-repaired knee.

CONCLUSION

After repair of the MPFL, adding an LRR lowered the ability of the patella to resist lateral displacement.

CLINICAL RELEVANCE

According to this study, LRR may not be routinely appropriate as a part of the stabilizing procedure to address acute patellar dislocation when the MPFL is avulsed from the patella.

Role of pathophysiology of patellofemoral instability in the treatment of spontaneous medial patellofemoral subluxation: a case report

INTRODUCTION

Medial patellar subluxation is usually seen after lateral retinacular release. Spontaneous medial subluxation of the patella is a very rare condition. There are few reports in the literature on the pathophysiology of iatrogenic medial patellar subluxation. To our knowledge, there are no reports of the pathophysiology of non-iatrogenic medial patellar subluxation in the English literature. In this study we present a case of spontaneous medial patellar instability that is more prominent in extension during weight bearing. We also try to define the treatment protocol based on pathophsiology.

CASE PRESENTATION

We report the case of a 21-year-old Turkish man with spontaneous medial patellar instability. He had suffered right knee pain, clicking and popping sensation in the affected knee for three months prior to presentation. Clinical examination demonstrated medial patellar subluxation that is more prominent in extension during the weight bearing phase of gait and while standing. Increased medial tilt was observed when the patella was stressed medially. Conventional anterior to posterior, lateral and Merchant radiographs did not reveal any abnormalities. After three months of physical therapy, our patient was still suffering from right knee pain which disturbed his gait pattern. Throughout the surgery, medial patellar translation was tested following the imbrication of lateral structures. He still had a medial patellar translation that was more than 50% of his patellar width. Patellotibial ligament augmentation using an iliotibial band flap was added. When examined after surgery, the alignment of the patella was effectively corrected.

CONCLUSIONS

Chronic imbalance between the strengths of vastus lateralis and vastus medialis results in secondary changes in passive ligamentous structures and causes additional instability. Physical therapy modalities that aim to strengthen the vastus lateralis might be sufficient for the treatment of spontaneous medial instability. There would be no need for any surgical intervention if spontaneous medial instability was recognized before the additional instability occured. If necessary, lateral imbrication followed by lateral patellotibial ligament augmentation can be performed, and these would effectively correct spontaneous medial patellofemoral instability.

The 3-in-1 procedure for recurrent dislocation of the patella in skeletally immature children and adolescents

BACKGROUND

Recurrent patellar dislocations are common injuries in children and adolescents. The subjective and functional results of soft tissue surgical management in a population that was skeletally immature at the time of surgery have not been reported.

HYPOTHESIS

The 3-in-1 procedure is an effective treatment for recurrent patellar dislocation in skeletally immature patients.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Twenty-five skeletally immature patients (age at operation, 13.5 +/- 3.8 years) who were practicing sports and suffering from recurrent unilateral patellar dislocation were included in the study and followed until skeletal maturation. Clinical evaluation included the modified Cincinnati rating system and the Kujala score, anthropometry, plain radiography, and isokinetic dynamometry.

RESULTS

The average follow-up was 3.8 years (range, 2.5-6 years). The mean modified Cincinnati score increased from 51.7 +/- 12.6 preoperatively to 94.3 +/- 10.8 (P < .02), while the mean Kujala scores increased from 52.4 +/- 12.7 preoperatively to 93.8 +/- 14.2 (P < .02). The Insall-Salvati index remained essentially unchanged, being 1.04 +/- 0.2 preoperatively and 1.02 +/- 0.3 at latest follow-up. Significant differences were found between the operated and the contralateral limb in the various isokinetic strength variables at all angular velocities measured at the latest follow-up (.05 < P < .0042).

CONCLUSION

The 3-in-1 procedure is a safe, reliable management option for recurrent patellar dislocation in skeletally immature patients. Side-to-side differences in isokinetic strength and in anthropometric indices persist despite subjective success of the procedure.

Isolated medial patellofemoral ligament reconstruction for recurrent patellar dislocation

BACKGROUND

Several medial patellofemoral ligament reconstruction procedures have been proposed to manage recurrent patellar dislocation.

HYPOTHESIS

Reconstruction of the medial patellofemoral ligament using a hamstring graft with a 2 transverse patellar tunnels technique is an effective treatment for recurrent patellar dislocation in patients without any evident predisposing factors.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Twenty-eight patients with chronic patellar instability without any anatomic predisposing factors, experiencing recurrent unilateral patellar dislocation, were included in the study. Evaluation included the modified Cincinnati and the Kujala scores, anthropometry, plain radiography, and isokinetic dynamometry.

RESULTS

The average follow-up was 3.1 years (range, 2.5-4 years). The mean modified Cincinnati score increased from 52 preoperatively to 89 (P = .001). The mean Kujala scores increased from 45 preoperatively to 83 (P = .03). The muscle volume of the thigh of the operated limb increased with time, but remained less well developed than the nonoperated limb (P = .04). The mean Insall-Salvati index was 1.1 (range, 0.9-1.2) preoperatively and remained within normal range (1.1 [range, 0.9 to 1.2]) (P = .07), at latest follow-up. Significant isokinetic strength differences were found between the operated and the contralateral limbs (.05 < P < .006), even at the latest follow-up. Three patients experienced a new patellar dislocation.

CONCLUSION

Medial patellofemoral ligament reconstruction using hamstring tendon passed through a double patellar transverse bony tunnel technique is a safe, reliable management option for recurrent patellar dislocation in patients without any predisposing anatomic factors.

Surgical correction of limb malalignment for instability of the patella: a comparison of 2 techniques

BACKGROUND

Although patients considered "successful" at longer-term follow-up no longer exhibited patellar instability, those with more severe malalignment issues had other, gradually worsening symptoms such as activity-related pain, crepitation, swelling with activities, and pain with weather changes.

HYPOTHESIS

Improvement of patellar tracking by correction of the tubercle-sulcus angle and related ligament deficiencies will result in good to excellent results, regardless of the technique employed.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Twenty-five patients with dislocating patellae and significant lower leg deformity were treated; 12 patients (group 1) underwent a derotational high tibial osteotomy and 13 patients (group 2) underwent an Elmslie-Trillat-Fulkerson proximal-distal realignment. All were prospectively evaluated a minimum of 24 months postoperatively with a physical examination, validated outcome questionnaires, radiographs, and computerized axial tomography scans. Postoperative 3-dimensional bilateral gait analyses were performed on all subjects walking on a 3-dimensional force treadmill to measure stance kinematics, foot progression angle, knee flexion, knee valgus-varus, hip flexion, and patella angle. Contralateral limbs with similar preoperative alignment were used as controls.

RESULTS

Group 1 patients significantly improved over their preoperative status in all primary subjective and functional outcome parameters, and were significantly better than group 2 patients. Group 2 patients improved, but not to the degree of group 1 patients. Gait analysis revealed group 1 patients had more symmetrical gait patterns, with less variability and less compensatory gait changes, than group 2 patients.

CONCLUSION

The original hypothesis proved to be incorrect. The simultaneous correction of ligament imbalance, excessive tubercle-sulcus angle, and lower limb torsional deformity produced significantly better results than conventional proximal-distal realignment.

Associates of physical function and pain in patients with patellofemoral pain syndrome

OBJECTIVES

To explore whether impairment of muscle strength, soft tissue length, movement control, postural and biomechanic alterations, and psychologic factors are associated with physical function and pain in patients with patellofemoral pain syndrome (PFPS).

DESIGN

Cross-sectional study.

SETTING

Rehabilitation outpatient.

PARTICIPANTS

Seventy-four patients diagnosed with PFPS.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Measurements were self-reported function and pain; strength of quadriceps, hip abduction, and hip external rotation; length of hamstrings, quadriceps, plantar flexors, iliotibial band/tensor fasciae latae complex, and lateral retinaculum; foot pronation; Q-angle; tibial torsion; visual observation of quality of movement during a lateral step-down task; anxiety; and fear-avoidance beliefs.

RESULTS

After controlling for age and sex, anxiety and fear-avoidance beliefs about work and physical activity were associated with function, while only fear-avoidance beliefs about work and physical activity were associated with pain.

CONCLUSIONS

Psychologic factors were the only associates of function and pain in patients with PFPS. Factors related to physical impairments did not associate to function or pain. Our results should be validated in other samples of patients with PFPS. Further studies should determine the role of other psychologic factors, and how they relate to anxiety and fear-avoidance beliefs in these patients.

[Lateral retinacular release]

This overview of numerous studies discusses, based on short-term and long-term results, which diagnoses are indications for lateral retinacular release. No significant differences in outcome between arthroscopic and open lateral release could be documented. Isolated lateral release offers a good success rate for treating a stable patella with excessive lateral pressure. In patellar instability, the results are less favorable in long-term follow-up evaluation. Hyperlaxity with hypermobility of the patella is an absolute contraindication. Lateral release provides only temporary benefit for patellofemoral osteoarthritis. Proximal and/or distal realignment of the extensor mechanism gives better results than isolated lateral release.

The reliability and validity of the Q-angle: a systematic review

The quadriceps or Q-angle is an index of the vector for the combined pull of the extensor mechanisms and the patellar tendon. It is used as an indicator for patellofemoral joint dysfunction. The purpose of this article is to systematically review and appraise the literature to determine the reliability and validity of this test. An electronic database search was performed accessing AMED, British Nursing Index, CINAHL, the Cochrane database, EMBASE, ovid Medline, Physiotherapy Evidence Database (PEDro), PsycINFO, Pubmed and Zetoc to April 2008. All English language, human subject, clinical trials, assessing the inter- or intra-tester reliability, or the criterion validity, were included. The Critical Appraisal Skills Programme appraisal tool was used to establish the methodological quality of each study. Ten articles including 569 control and 179 patellofemoral disorder knees were reviewed. The findings suggest that there is considerable disagreement on the reliability and validity of the clinical Q-angle measurement. This may be due to a lack of standardisation in the measurement procedure. Further study is advocated to re-evaluate this topic using well-designed, and sufficiently large observational studies of specific patellofemoral dysfunction populations.

Patellar instability

Recurrent patellar instability can result from osseous abnormalities, such as patella alta, a distance of >20 mm between the tibial tubercle and the trochlear groove, and trochlear dysplasia, or it can result from soft-tissue abnormalities, such as a torn medial patellofemoral ligament or a weakened vastus medialis obliquus. Nonoperative treatment includes physical therapy, focusing on strengthening of the gluteal muscles and the vastus medialis obliquus, and patellar taping or bracing. Acute medial-sided repair may be indicated when there is an osteochondral fracture fragment or a retinacular injury. The recent literature does not support the use of an isolated lateral release for the treatment of patellar instability. A patient with recurrent instability, with or without trochlear dysplasia, who has a normal tibial tubercle-trochlear groove distance and a normal patellar height may be a candidate for a reconstruction of the medial patellofemoral ligament with autograft or allograft. Distal realignment procedures are used in patients who have an increased tibial tubercle-trochlear groove distance or patella alta. The degree of anteriorization, distalization, and/or medialization depends on associated arthrosis of the lateral patellar facet and the presence of patella alta. Associated medial or proximal patellar chondrosis is a contraindication to distal realignment because of the potential to overload tissues that have already undergone degeneration.

Using an iliotibial tract for patellar dislocation in children

OBJECTIVE

To evaluate the clinical and functional results of surgical treatment of patellar dislocation in children.

MATERIAL AND METHODS

A prospective study was undertaken from January 1995 to December 2004. Patients who suffered from patellar dislocation after receiving intramuscular antibiotic injections to quadriceps were recruited. A complete history of each patient was recorded, and both a clinical and a roentgenographic examination were performed preoperatively. Patellar dislocation was classified according to Bensahel's criteria. The iliotibial tract and lateral retinacula was released to restore the tension of the medial retinaculum. Quadricepsplasty was used in all patients for full flexion of knee.

RESULTS

There were nine males and 65 females in this study. All 74 patients (76 knees) developed dislocation of the patella after repeated intramuscular injections of antibiotic(s) into the quadriceps muscle. Fifty-six knees (73.7%) were type 1, and 20 knees (26.3%) were type 2 (Bensahel's classification). In all, we attained excellent results in 56 knees (73.7%), good results in 17 knees (22.4%), and fair results in three knees (3.9%). There have been no poor results or recurrences so far.

CONCLUSION

Use of the iliotibial tract, adequate lateral retinacular release, restoration of the tension of the medial retinaculum and associated quadricepsplasty achieved a high success rate. The technique is simple, safe and effective in skeletally immature children.

[Isolated arthrosis of the patellofemoral joint in younger patients (<50 years)]

In the majority of cases, arthrosis of the patellofemoral joint (PFJ) is combined with arthrosis of the femorotibial compartment and thus assumes a somewhat secondary role. Nevertheless, it can occur as an isolated entity. Several radiological studies evidenced isolated degenerative alterations in the PFJ in the age group >55 years (13.6-24.0% in women and 11.0-15.4% in men). In younger patients the incidence is lower and is mainly associated with patellar instability or post-traumatic arthrosis. Just the same, the choice of appropriate treatment for these patients is challenging. Total replacement can be recommended for older and less active patients. In contrast, for younger and more active patients, various conservative treatment options and more demanding operative techniques are available to the surgeon to avoid arthroplasty. This article describes the different therapeutic possibilities for managing arthrosis of the PFJ in patients aged <50 years.

Adolescent patellofemoral pain: implicating the medial patellofemoral ligament as the main pain generator

PURPOSE

The purpose of this study is to define the clinical presentation of adolescent patellofemoral pain.

METHODS

A review was completed of all patients with patellofemoral pain at a children's hospital sports clinic over a 3-year period.

RESULTS

One hundred and one patients (91 female) with 136 symptomatic knees were identified. Mean age was 14.4 years. Knee pain was localized to the anteromedial or anterior region of the knee in 96% of patients and was typically produced with running (94%), jumping (92%) and stair use (69%). On physical examination there was usually a non antalgic gait (99%), no patellofemoral crepitation (98%), normal lower extremity angular (84%) and rotational alignment (94%), with no foot malalignment (>97%). The medial patellofemoral ligament (MPFL) was the most palpably tender area of the knee in 98% of patients. During "lateral apprehension" testing, 89% had pain at the MPFL, but not true apprehension. A "J-sign" was present at terminal knee extension in 65%. Mean Q-angle was 18.7 degrees . Means of all radiographic measures were within normal ranges.

CONCLUSION

The prototypical patient had anterior/anteromedial knee pain of insidious onset during running and jumping. The most consistent physical findings were focal tenderness at the MPFL, positive terminal J-sign, and an elevated Q-angle. Most patients required only nonsurgical treatments, but 18% underwent surgical interventions for persistent pain.

Comparison of patellar mobility in female adults with and without patellofemoral pain

STUDY DESIGN

Case control study.

OBJECTIVE

To compare the patellar mobility of female adult subjects with and without patellofemoral pain (PFP).

BACKGROUND

Although abnormal patellar mobility is believed to be one of the causes of PFP, there is currently no published evidence to support this contention. In part, this lack of evidence is because a reliable clinical measurement method to measure patellar mobility and objective criteria to define abnormal patellar mobility have not been established.

METHODS AND MEASURES

The study sample was comprised of 22 females with PFP (PFP group) and 22 females who had no knee pain (control group), matched by age, height, and body mass index to the subjects with PFP. Patellar mobility was measured objectively using a specially designed apparatus. Measurements of lateral and medial patellar displacement, patellar mobility balance (lateral minus medial patellar displacement), lateral patellar mobility index (lateral patellar displacement divided by patellar width), and medial patellar mobility index (medial patellar displacement divided by patellar width) were used.

RESULTS

Lateral and medial patellar mobility values were not significantly different between the individuals in the PFP and control groups. When normal patellar mobility was arbitrarily defined as the average mobility +/- 2 SDs, based on the data from the control group, normal lateral patellar displacement was within a range of 7.2 to 17.6 mm and normal medial patellar displacement was within a range of 6.8 to 14.0 mm. The intraclass correlation coefficient for intratester and intertester reliability of lateral and medial patellar displacement measurements varied from 0.80 to 0.97.

CONCLUSION

Although there were no significant differences in patellar mobility between females with and without PFP, these measurements give reference information about normal patellar mobility for this group.

LEVEL OF EVIDENCE

Diagnosis, level 5.

The management of recurrent patellar dislocation

Acute and chronic trauma, chronic abnormal joint loading conditions, and hemarthroses have been implicated in the development of degenerative joint disease. Patellar instability with acute and recurrent patellar dislocation provides all of these ingredients. This article describes an approach to the treatment of recurrent patellar instability that considers the unique features and expectations of the patient rather than using a generic algorithm.

Partial lateral patellar facetectomy for treatment of arthritis due to lateral patellar compression syndrome

PURPOSE

The purpose of this study was to investigate the intermediate-term results of a retrospective clinical trial designed to establish the value of lateral retinaculum release of the patella in conjunction with partial lateral patella facetectomy in patients with stage III or stage IV patellofemoral arthritis.

METHODS

Between October 1992 and January 2005, all patients undergoing arthroscopy, lateral patellar retinaculum release, and lateral patella facetectomy were evaluated. In total, 66 knees in 63 patients (89%) were available for evaluation at a mean of 60 months after the index surgery. Evaluations consisted of preoperative and postoperative questionnaires, physical examinations, and radiographs. The main outcome measure was the Kujala patellofemoral score.

RESULTS

For those patients not undergoing total knee arthroplasty before evaluation, the mean Kujala score was 45.6 preoperatively and 72.0 postoperatively (P < .001); subjectively, 56% of patients were very satisfied, 32% satisfied and would repeat the procedure, 5% were indifferent, and 7% were dissatisfied and would not repeat the procedure. Including all patients who underwent total knee arthroplasty before evaluation and those who would not repeat the procedure or were indifferent, our accumulative failure rate was 17%. Correlations of several measures with the Kujala score, as well as subgroup comparisons of several measures between patients who were satisfied and those who were not satisfied with their reconstructions, were performed. However, all of these failed to achieve statistical significance after adjustment for multiple comparisons and so are not reported in this report.

CONCLUSIONS

Lateral patella retinaculum release and partial lateral patella facetectomy for end-stage patellofemoral disease provides up to 5 years of symptomatic relief in over 80% of carefully selected patients who do not have significant arthritis (grade IV) in the medial or lateral knee compartments. Significant lateral facet patellofemoral arthritis (grade IV) even in association with medial facet and femoral sulcus involvement is not a contraindication to this surgical approach.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

The diagnostic value of the Clarke sign in assessing chondromalacia patella

CONTEXT

Various techniques have been described for assessing conditions that cause pain at the patellofemoral (PF) joint. The Clarke sign is one such test, but the diagnostic value of this test in assessing chondromalacia patella is unknown.

OBJECTIVE

To (1) investigate the diagnostic value of the Clarke sign in assessing the presence of chondromalacia patella using arthroscopic examination of the PF joint as the "gold standard," and (2) provide a historical perspective of the Clarke sign as a clinical diagnostic test.

DESIGN

Validation study.

SETTING

All patients of one of the investigators who had knee pain or injuries unrelated to the patellofemoral joint and were scheduled for arthroscopic surgery were recruited for this study.

PATIENTS OR OTHER PARTICIPANTS

A total of 106 otherwise healthy individuals with no history of patellofemoral pain or dysfunction volunteered.

MAIN OUTCOME MEASURE(S)

The Clarke sign was performed on the surgical knee by a single investigator in the clinic before surgery. A positive test was indicated by the presence of pain sufficient to prevent the patient from maintaining a quadriceps muscle contraction against manual resistance for longer than 2 seconds. The preoperative result was compared with visual evidence of chondromalacia patella during arthroscopy.

RESULTS

Sensitivity was 0.39, specificity was 0.67, likelihood ratio for a positive test was 1.18, likelihood ratio for a negative test was 0.91, positive predictive value was 0.25, and negative predictive value was 0.80.

CONCLUSIONS

Diagnostic validity values for the use of the Clarke sign in assessing chondromalacia patella were unsatisfactory, supporting suggestions that it has poor diagnostic value as a clinical examination technique. Additionally, an extensive search of the available literature for the Clarke sign reveals multiple problems with the test, causing significant confusion for clinicians. Therefore, the use of the Clarke sign as a routine part of a knee examination is not beneficial, and its use should be discontinued.

Long-term functional outcome after lateral patellar retinacular release in adolescents: an observational cohort study with minimum 5-year follow-up

BACKGROUND

Lateral patellar retinacular release has been recommended for patients with patellar tilt, tight lateral retinaculum, patellar subluxation, patellar dislocation, and patellofemoral pain. Studies of long-term outcomes after lateral release are limited, especially for differing indications.

HYPOTHESIS

Adolescents do well after lateral retinacular release in the 5- to 22-year time frame.

METHODS

Patients having undergone lateral retinacular release between the years of 1981 and 1999 were contacted. Evaluation was by the Cincinnati and Lysholm scales and by level of satisfaction and need for reoperation.

RESULTS

One hundred forty knees were studied. Mean age at operation was 15.4 years (SD, 2.7 years). Average follow-up was 8.5 (SD, 4.1 years; range, 5.2-22.5 years). Twenty-five patients had needed reoperation, indicating failure of the index operation. Kaplan-Meier survivorship was 78% at 15 years. Cincinnati and Lysholm scores indicated well-functioning knees in those not requiring reoperation. Overall satisfaction improved as time from operation increased. Comparisons were made between the group requiring reoperation and those who did not. Focus was placed on knees with patellar maltracking or tilt versus patellar instability and between males and females. No differences were found among groups for reoperation rate, level of satisfaction, average Lysholm score, or average Cincinnati score. There were no differences in demographics or outcome measures between patients with patellar instability and those with tilt. Instability patients trended toward higher reoperation rates than did tilt patients, but the difference was not significant. There were no differences between males and females.

CONCLUSION

The majority of patients are satisfied with their knee 5 to 22 years after lateral patellar retinacular release and scored well on questions rating knee health and function.

Current concepts review: comprehensive physical examination for instability of the knee

A careful history and physical examination are the cornerstones of orthopaedic sports medicine. When evaluating a patient for ligamentous instability of the knee joint, an understanding of the contribution of anatomic structures to stability enhances a practitioner's ability to achieve an accurate clinical diagnosis. This article reviews the various types of knee instability and the associated anatomic structures. Ultimately, information must be obtained from multiple tests to reach the final diagnosis. We describe in detail the pathologic and biomechanical basis of the tests for both tibiofemoral and patellofemoral instability of the knee joint and provide recommendations for performance and interpretation of these physical examinations.