Patellofemoral arthritis

Robotic Assisted Patellofemoral Joint Replacement: Surgical Technique, Tips and Tricks

In this article we wish to provide MAKO robotic knee users a surgical guide including tips and tricks on performing MAKO robotic-assisted patellofemoral joint replacements. The senior authors in this paper from the Exeter Knee Reconstruction Unit, United Kingdom are highly experienced MAKO users who have been performing MAKO assisted Patellofemoral joint replacements since 2017.

Treatment of Unicompartmental Cartilage Defects of the Knee with Unicompartmental Knee Arthroplasty, Patellofemoral Partial Knee Arthroplasty or Focal Resurfacing

Focal chondral defects are common lesions of the articular cartilage. They are predominantly found on the medial femoral condyle and often progress to osteoarthritis of the knee. Various conservative treatment options are available. The conservative treatment might reduce pain and delay the progress of degenerative processes. However, restoration of the articular cartilage cannot be accomplished. If the conservative treatment fails unicompartmental arthroplasty, patellofemoral joint replacement or focal resurfacing are reasonable options to postpone total knee arthroplasty. A careful patient selection before surgery is crucial for all three treatment options. The following overview reports indications and outcomes of medial partial knee replacement, patellofemoral partial knee replacement, and focal resurfacing treatment options for focal chondral defects.

Patellofemoral arthroplasty versus total knee arthroplasty for isolated patellofemoral osteoarthritis: a systematic review and meta-analysis

BACKGROUND

Isolated patellofemoral osteoarthritis (PF-OA) is a common subtype of knee osteoarthritis, leading to a huge economic burden on health care systems. Although previous studies have shown that patellofemoral arthroplasty (PFA) and total knee arthroplasty (TKA) have good clinical effects, it remains largely unclear which treatment is more effective for patients with isolated PF-OA. We aimed to compare postoperative function, complications, revision rates, level of physical activity, and satisfaction rate between the two surgical techniques.

METHODS

Our study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Search of literature was conducted in MEDLINE, EMBASE, Cochrane Library, and Web of Science until November 2020. The included studies were those that provided direct comparison of postoperative outcomes between PFA and TKA. Data were extracted from eligible studies and combined to calculate the pooled odds ratio (OR) and 95% confidence interval (CI). Sensitivity analysis and subgroup analysis were conducted to evaluate heterogeneity between the two groups.

RESULTS

A total of 7 eligible studies (3 recent randomized controlled trials and 4 nonrandomized controlled trials) were included in this meta-analysis. The pooled results showed that both the PFA group and the TKA group had improved postoperative indicators, suggesting that the two operation modes could improve the knee function and quality of life of patients. Throughout the first 2 years postoperatively, higher activity level, and better functional recovery were observed for PFA compared with TKA in this study; moreover, the differences between the two operation modes were statistically significant (p < 0.05). We found no significant difference in complications, revision rates, and satisfaction rate between the two procedures.

CONCLUSION

Although there was no observed difference in the complications, revision rates, and satisfaction rate between PFA and TKA, PFA was superior to TKA in terms of knee function and physical activity in the first 2 years postoperatively. Therefore, PFA is a safe, effective, and less invasive treatment for patients with isolated PF-OA. Our findings are consistent with the systematic review of current evidence that PFA may be more suitable for younger patients with high activity needs. Patient selection is, therefore, thought to be of paramount importance. Individualized surgical plan should be designed according to the patient's age, BMI, KOA site, and activity level and combined with the doctor's personal experience.

[Patellofemoral inlay implants-an innovation in patellofemoral joint arthroplasty?]

Isolated arthrosis of the patellofemoral joint is a rare and complex disease. After conservative therapy has been exhausted, the orthopedist has various soft-tissue and bone reconstructive procedures as well as cartilage regenerative procedures at his hands. In cases of failed or unsatisfactory therapy, patellofemoral arthroplasty continues to be controversially discussed as an alternative therapy. A closer look at these studies reveals promising results with the correct indication and patient selection. The different prosthesis designs provide good postoperative results while considering general and specific risks. The current generation of patellofemoral inlay prostheses shows high patient satisfaction with significant improvements in knee function and pain relief in mid-term outcomes. However, a relatively high revision rate must be considered.

Development and evaluation of a minimally aggressive method of patellofemoral osteoarthritis surgical treatment

PURPOSE

The purpose of this study was to assess the impact of developed minimally invasive operation such as the partial lateral facetectomy (PLFE) with patella thickness resection in patients with lateral patellofemoral (PF) osteoarthritis on short-term clinical and radiographic outcomes.

METHODS

This is a prospective study of 27 knees in 27 patients (18 females and 9 males, mean aged at surgery 59.1-year old) whom a PLFE with patella thickness resection using developed minimally invasive method was performed. Data of preoperative and postoperative questionnaires, physical examinations, and radiographs were analyzed. The minimum follow-up was 12 months (mean, 24.1 months; range, 12-36 months).

RESULTS

The subjective outcomes included the anterior pain relief assessed by scores using the Western Ontario and McMaster Universities Arthritis Index score (scores improved considerably by 2.34 points with respect to pain and by 1.63 points with respect to function), visual analog scale, and Knee Society Score (that improved in 78% of the knees). The majority of these patients experienced improvement in their PF symptoms. The PF index decreased considerably after surgery. The mean patellar width and thickness were decreased after surgery, maintaining a width/thickness ratio of 1.8:1.0 after surgery.

CONCLUSION

PLFE with patella thickness resection aiming to decrease the high pressure in the lateral facet and improving congruence of the patella confirmed frequent pain relief. This surgical procedure is minimally invasive, relatively simple, and effective in selected patients and can be a valid early alternative to more complex operations. Level of Evidence: Level IV Therapeutic study.

Minimally Invasive Robotic-Assisted Patellofemoral Arthroplasty

Isolated patellofemoral arthritis is a common debilitating condition in adults older than 40 years of age. Surgical options such as patellofemoral arthroplasty exist for those who failed to respond to nonoperative treatment. However, early patellofemoral arthroplasty techniques often resulted in poor outcomes due to mal-tracking and malalignment of components. Robotic-assisted surgery recently has been introduced as an alternative to classic patellofemoral arthroplasty, with the potential to improve the anatomical fit and reproducibility of implant positioning. We present the technique for minimally invasive robotic-assisted patellofemoral arthroplasty system.

Preoperative patellofemoral anatomy affects failure rate after isolated patellofemoral inlay arthroplasty

PURPOSE

To analyze whether preoperative patellofemoral anatomy is associated with clinical improvement and failure rate after isolated patellofemoral arthroplasty (PFA) using a modern inlay-type trochlear implant.

METHODS

Prospectively collected 24 months data of patients treated with isolated inlay PFA (HemiCAP^® Wave, Arthrosurface, Franklin, MA, USA) between 2009 and 2016, and available digitalized preoperative imaging (plain radiographs in three planes and MRI) were retrospectively analyzed. All patients were evaluated using the WOMAC score, Lysholm score, and VAS pain. Patients revised to TKA or not achieving the minimal clinically important difference (MCID) for the total WOMAC score or VAS pain were considered failures. Preoperative imaging was analyzed regarding the following aspects: Tibiofemoral OA, patellofemoral OA, trochlear dysplasia (Dejour classification), patellar height (Insall-Salvati index [ISI]; Patellotrochlear index [PTI]), and position of the tibial tuberosity (TT-TG and TT-PCL distance).

RESULTS

A total of 41 patients (61% female) with a mean age of 48 ± 13 years could be included. Fifteen patients (37%) were considered failures, with 5 patients (12%) revised to TKA and 10 patients (24%) not achieving MCID for WOMAC total or VAS pain. Failures had a significantly higher ISI, and a significantly lower PTI. Furthermore, the proportion of patients with a pathologic ISI (> 1.2), a pathologic PTI (< 0.28), and without trochlear dysplasia were significantly higher in failures. Significantly greater improvements in clinical outcome scores were observed in patients with a higher preoperative grade of patellofemoral OA, ISI ≤ 1.2, PTI ≥ 0.28, TT-PCL distance ≤ 21 mm, and a dysplastic trochlea.

CONCLUSION

Preoperative patellofemoral anatomy is significantly associated with clinical improvement and failure rate after isolated inlay PFA. Less improvement and a higher failure rate must be expected in patients with patella alta (ISI > 1.2 and PTI < 0.28), absence of trochlear dysplasia, and a lateralized position of the tibial tuberosity (TT-PCL distance > 21 mm). Concomitant procedures such as tibial tuberosity transfer may, therefore, be considered in such patients.

LEVEL OF EVIDENCE

Level III, retrospective analysis of prospectively collected data.

Hermes patellofemoral arthroplasty: Annual revision rate and clinical results after two to 20 years of follow-up

BACKGROUND

Patellofemoral arthroplasty (PFA) is an alternative to a total knee arthroplasty (TKA) in patients with severe isolated patellofemoral osteoarthritis. The main goal of this study was to determine the revision rate of the Hermes™ (Ceraver) anatomical unconstrained PFA.

METHODS

A retrospective single surgeon study was performed including all patients operated for PFA between 1997 and 2015. A standardized procedure was used to perform PFA with one type of prosthesis. All patients in the study were contacted at the final follow-up. The main judgment criterion was the annual rate of revision. Secondary criteria were the severity of anterior knee pain on a numerical scale (0-10) and functional scores (IKS and AKP scores).

RESULTS

During this period, PFA was performed in 64 patients (74 PFA), 52 women/12 men, mean age at surgery 59.6 ± 11.8 (31.3-82.1) years old. Four patients (5.4% of PFA) were lost to follow-up. Mean follow-up for the remaining 70 PFA was 7.5 ± 7.1 (2-20) years. TKA was required in 10 (14.3%) patients after a mean 5.4 ± 3.4 (1-9.3) years. The annual rate of revision was two-percent CI_95% [1.1-3.7%] if TKA was considered to be the defining event and 3.1% CI_95% [1.9-5.1%] for all types of revision (partial/total PFA replacement or TKA). Patients who underwent revision were significantly younger. After a mean eight (2-20) years of follow-up, mean anterior pain, the IKS and AKP scores improved significantly.

CONCLUSION

In this series, 78.6% of patients with a Hermes™ PFA did not require any revision after a follow-up of between two and 20 years.

LEVEL OF EVIDENCE

Level IV - retrospective study.

Axial-Oblique Versus Standard Axial 3-T Magnetic Resonance Imaging for the Detection of Trochlear Cartilage Lesions: A Prospective Study

Background:

Imaging of the femoral trochlea has been inherently difficult because of its convex anatomy.

Purpose/Hypothesis:

The purpose of this study was to compare the diagnostic utility of a standard axial magnetic resonance imaging (MRI) sequence with an axial-oblique MRI sequence of the knee for the detection of trochlear articular cartilage lesions on a high-field 3-T MRI scanner. We hypothesized that axial-oblique MRI scans of the knee obtained along the true axis of the trochlea would significantly improve the detection of high-grade cartilage lesions.

Study Design:

Cohort study (diagnosis); Level of evidence, 2.

Methods:

Patients who underwent MRI and subsequent surgery for any indication were prospectively enrolled into this study between June 2014 and February 2015. The articular cartilage of the trochlea was evaluated independently by 3 raters on axial and axial-oblique MRI and compared with arthroscopic findings (gold standard). The interrater and intrarater reliability of mild (International Cartilage Repair Society [ICRS] grades 1 or 2) and severe (ICRS grades 3 or 4) lesions on MRI were assessed as well as the sensitivity, specificity, positive predictive value, and negative predictive value.

Results:

A total of 99 knees in 96 patients were included in the study. Interrater and intrarater agreement for the identification of severe lesions were moderate to good on the proximal trochlea and fair to moderate on the distal trochlea. No significant differences in sensitivity were found between axial and axial-oblique scans for any grade of lesion (55% vs 51%, respectively; P = .700) or for severe lesions (61% vs 52%, respectively; P = .289). Similarly, specificity for detecting severe lesions was not significantly different between axial and axial-oblique scans (95% vs 87%, respectively; P = .219). Last, no significant differences in sensitivity or specificity were found between MRI sequences when separately evaluating proximal and distal trochlear lesions (all P > .05).

Conclusion:

The axial-oblique sequence was unable to improve the sensitivity of MRI in detecting articular cartilage lesions on the trochlea. Both conventional axial and axial-oblique sequences, reviewed independently of the complete MRI series, had low sensitivity in detecting trochlear articular cartilage lesions. For this reason, clinicians should utilize all MRI planes to evaluate the articular cartilage of the trochlea. Future studies should focus on improving MRI techniques for detecting and characterizing cartilage lesions of the trochlea.

Patellofemoral Arthroplasty: Current Concepts and Review of the Literature

Patellofemoral osteoarthritis (PFOA) can be associated with anterior knee pain, stiffness, and functional impairment. Some authors report that PFOA affects approximately 9% of patients older than 40 years with a greater prevalence in females. Etiology of PFOA is multifactorial and is related to the presence of abnormal stresses at the PF joint due to knee- and patient-related factors. The need for a joint preserving treatment by isolated replacement of the injured compartment of the knee led to the development of PF arthroplasty (PFA). When a correct PF replacement is performed, PFA preserves physiologic tibiofemoral joint, thus allowing patients for a rapid recovery with a high satisfaction. The outcomes for PFA are quite variable with a trend toward good to excellent results, mainly owing to the improvement in surgical techniques, patient selection, and implant design. The development of the second generation of PFA improved the outcomes, which is attributed to the different trochlear designs. Recently, encouraging results have been provided by the association of PFA and unicompartmental knee arthroplasty (UKA). In many studies, the main cause of PFA failure is progression of tibiofemoral OA. The aim of this brief review of literature is to summarize the clinical features, indications and contraindications, surgical techniques, complications, and outcomes of PFA.

Functional outcomes after patellar autologous osteochondral transplantation

PURPOSE

The aim of the present study was to assess clinical evaluation of patients who underwent autologous osteochondral transplantation of the patella.

METHODS

This prospective study assessed outcomes of 20 patients who underwent patellar autologous osteochondral transplantation at four time-points: preoperatively, 3 days, 6 months, and 2 years after surgery. The following outcomes were assessed at each time-point: pain (VAS), gait, swelling, trophic status, muscle strength, patellar mobility, and range of motion. The Tegner scale was also applied for each time-point.

RESULTS

All parameters improved, except for patellar mobility, which did not show any change. Pain score decreased from 7.1 (SD 2.3) to 2.4 (SD 2.6) at the 2-year assessment; limping decreased from 70 % before surgery to 15 % 2 years later; swelling scores decreased from an average of 1.8 (SD 0.8) 3 days after surgery to 0.5 (SD 0.7) at the 2-year assessment; muscle strength increased from 3.9 (SD 0.8) to 4.7 (SD 0.7) points at final follow-up; and the range of motion increased from 84 (SD 16.2) to 132 (SD 10.7) degrees 2 years later. Tegner score before surgery ranged from 0 to 5, and after 2 years, it ranged from 5 to 9.

CONCLUSION

Autologous osteochondral transplantation for the treatment of patellar chondral lesion was associated with significant improvement in pain, gait, swelling, and range of motion 2 years after surgery, achieving scores similar to uninjured knees. Most of them were able to return to sports activity after 6 months (recreational level) and 2 years (competitive level).

LEVEL OF EVIDENCE

IV.

Autologous Chondrocyte Implantation to Isolated Patella Cartilage Defects

Background Autologous chondrocyte implantation (ACI) is a durable treatment for patients with chondral defects. This study presents the comprehensive evaluation of patients with patella defects treated with ACI at medium- to long-term follow-up. Methods Thirty consecutive patients with isolated chondral lesions of the patella were enrolled prospectively. Primary outcome measures were validated patient reported outcome measures and objective magnetic resonance imaging. Results Nineteen of 30 patients underwent tibial tubercle osteotomy (TTO) to correct lateral maltracking in combination with soft tissue balancing. The defect sizes were large, averaging 4.7 ± 2.1 cm² (range 2.2-30.0 cm²). Pidoriano/Fulkerson classification revealed that 3 defects were type II (lateral), 9 were type III (medial), and 18 were type IV (central/panpatella). Age at the time of surgery was 32 ± 10 years. At follow-up of 2 to 14 years, knee function was rated good to excellent in 25 (83%) patients, fair in 4 (13%) patients, and poor in 1 (3%) patient. Three patients failed treatment after a mean of 75 months (6.25 years). All 3 failures were Workers Compensation (WC) cases. They were older than the non-WC patients, 42 ± 6 years compared with the non-WC 28 ± 9 years ( P = 0.0019). Significant increases in all clinical and health utility outcome scores were seen. Magnetic resonance imaging demonstrated that the fill grade, surface and integrity of the repair tissue correlated with clinical scores. Conclusion ACI to isolated patella defects results in significant functional improvement at a minimum of 24 months, with the results remaining durable at latest follow-up of 15 years. Level of evidence Level 4.

Nonligamentous Soft Tissue Pathology About the Knee: A Review

Knee pain is one of the most frequent complaints evaluated by orthopedic surgeons. It encompasses a broad range of pathology and can present in a variety of ways. Most of this pain can be attributed to essential structures of the knee, including the menisci, cruciate or collateral ligaments, and articular cartilage. However, there are underrecognized structures in and around the knee that can frequently be a cause of knee pathology and pain. Knee pain stemming from these structures may be missed or incorrectly diagnosed, and these patients often present for second and third opinions because of failure to diagnose and treat the underlying pathology. The synovial plica, suprapatellar pouch, lateral retinaculum, infrapatellar fat pad, and infrapatellar branch of the saphenous nerve are less common but still significant causes of knee pain. Although initial treatment involves various nonoperative modalities, operative treatment is often warranted. Operative and nonoperative management of these soft tissue structures may occur in isolation or with concomitant procedures, including knee ligament reconstruction, total knee arthroplasty, tibial tuberosity osteotomy, or lysis of adhesions. With proper recognition of the role of these structures in knee pain, the orthopedic surgeon can offer a valuable primary or adjunctive treatment option for patients with knee pain, especially those without localizing signs of meniscal, ligamentous, or cartilage damage.

A cadaveric investigation into the demographic and bony alignment properties associated with osteoarthritis of the patellofemoral joint

BACKGROUND

Patellofemoral joint osteoarthritis is common, although circumstances dictating its evolution and pathogenesis remain unclear. Advances in surgical technique have improved the ability to modify long-bone alignment in the coronal, sagittal, and axial planes. However, to our knowledge, there is no significant long-term data available in regard to the relationship between anatomic alignment parameters most amenable to surgical modification and patellofemoral joint osteoarthritis.

METHODS

Five-hundred and seventy-one cadaveric skeletons were obtained from the Hamann-Todd osteological collection. Mechanical lateral distal femoral angle, medial proximal tibial angle, tibial slope, femoral version, tibial torsion, the position of the tibial tubercle relative to the width of the tibial plateau, trochlear depth, and patellar size were measured using validated techniques. A previously published grading system for patellofemoral joint arthritis was used to quantify macroscopic signs of degenerative joint disease.

RESULTS

Increasing age (standardized beta 0.532, p<0.001), female gender (standardized beta 0.201, p=0.002), and decreasing mechanical lateral distal femoral angle (standardized beta -0.128, p=0.025) were independent correlates of increased patellofemoral joint osteoarthritis. A relatively more laterally positioned tibial tubercle trended towards predicting patellofemoral joint osteoarthritis (standardized beta 0.080, p=0.089).

CONCLUSIONS

These findings confirm that patellofemoral joint osteoarthritis is strongly associated with increasing age and female gender. Valgus alignment of the distal femur, a relatively more lateral location of the tibial tubercle, and a shallower trochlear grove appear to have modest effects on the development of patellofemoral joint osteoarthritis.

Epidemiological characteristics of patellofemoral osteoarthritis in elderly Koreans and its symptomatic contribution in knee osteoarthritis

BACKGROUND

Many studies have reported the prevalence of knee osteoarthritis (OA) but have invariably focused on the tibiofemoral (TF) joint and overlooked the patellofemoral (PF) joint. Accordingly, little epidemiological information is available regarding the PF OA. The purpose of the current study was to document the epidemiological characteristics of PF OA in elderly Koreans.

METHODS

Radiographic assessment was performed for 681 elderly (≥65 years old) Koreans recruited from a community, and symptom severity was evaluated using Western Ontario and McMaster Universities Index (WOMAC) and Short Form-36 (SF-36) scales. Prevalence of different categories of knee OA (isolated PF OA, isolated TF OA and combined PF and TF OA) was calculated. The symptoms of isolated PF OA group and non-OA group were compared.

RESULTS

The overall prevalence of OA was 22.0% in the PF compartment and 34.1% in the TF compartment. The prevalence of isolated PF OA, isolated TF OA, and combined PF and TF OA was 3.8%, 17.8%, and 19.2%, respectively. Female sex, aging, and obesity were not associated with isolated PF OA. No significant differences were found in any clinical outcome scales between the isolated PF and non-OA groups.

CONCLUSION

This study documents that OA in the PF joint is common in elderly Koreans, but isolated PF OA is rare. Demographic risk factors are not associated with isolated PF OA, suggesting that isolated PF OA may have a different pathophysiology from other types of knee OA. Our study also indicates that the presence of isolated PF OA should not be construed to be responsible for clinical symptoms.

[Patellofemoral arthroplasty: indication, technique and results]

BACKGROUND

Although patellofemoral arthroplasty has been used for more than 30 years, it is still a challenging subject in orthopedics. The reason for this are the complex kinematics of the patellofemoral joint which are influenced by dynamic and static factors. New implant concepts that incorporate multiple coronal and sagittal curvatures and surface controlled inlay implantation show a positive direction in modern patellofemoral arthroplasty.

OBJECTIVES

The purpose of this work is the review of the literature on patellofemoral arthroplasty and the presentation of our own experience.

METHODS

We present indications and surgical techniques of patellofemoral arthroplasty as well as the most important aspects of preoperative evaluation. The patellofemoral joint can be reconstructed using either an inlay or an onlay prosthesis. Both arthroplasty concepts are discussed. Additional pathologies like chronic patellofemoral instabilities due to dysplasia, valgus/varus or rotational malalignment, and soft-tissue alterations are addressed with concomitant procedures.

RESULTS

Both inlay and onlay arthroplasty have demonstrated good functional outcome scores in patients with patellofemoral osteoarthritis. Patients with patellofemoral instability and/or trochlear dysplasia may benefit more from patellofemoral arthroplasty than patients with primary osteoarthritis because not only pain but also secondary pathologies are addressed.

CONCLUSION

Patellofemoral arthroplasty is an effective and safe procedure if the indication criteria are respected and the specific surgical technique is used. However, comparative results on current inlay and onlay prostheses have not been published in the literature to date.

Patellectomy for osteoarthritis: a new tension preserving surgical technique to reconstruct the extensor mechanism with retrospective review of long-term follow-up

Background

The management of severe patellofemoral arthritis in young patients remains a significant problem. For many, patellofemoral replacement is not a desirable option. Current surgical techniques for patellectomy disrupt the extensor lever arm causing weakness. We describe a new technique that maintains the extensor mechanism tension and a case series showing good results for patella-only arthritis at a mean follow-up of 11 years.

Methods

Eight patellectomies were performed using a new surgical technique in patients with a mean age of 38 years, and an average follow-up of 11 years (range 8–16 years). Patients were followed up using a pain visual analogue scale, Lysholm knee score and patient-reported outcome measures.

Results

All patients experienced pain relief following surgery. Those with patella-only arthritis had better outcomes than patients who had patella and trochlea disease. All patients had either full or near full extension. Lysholm scores were better in patients who had disease confined to the patella.

Conclusion

We believe patellectomy with this tension-preserving technique has a role for the management of anterior knee pain secondary to severe patella-only arthritis in young patients where arthroplasty is not desirable.

Prospective evaluation of anatomic patellofemoral inlay resurfacing: clinical, radiographic, and sports-related results after 24 months

PURPOSE

To prospectively evaluate the clinical, radiographic, and sports-related outcomes at 24 months after isolated and combined patellofemoral inlay resurfacing (PFIR).

METHODS

Between 2009 and 2010, 29 consecutive patients with patellofemoral osteoarthritis (OA) were treated with the HemiCAP(®) Wave Patellofemoral Resurfacing System (Arthrosurface, Franklin, MA, USA). Based on preoperative findings, patients were divided into two groups: group I, isolated PFIR (n = 20); and group II, combined PFIR with concomitant procedures to address patellofemoral instability, patellofemoral malalignment, and tibiofemoral malalignment (n = 9). Patients were evaluated preoperatively and at 24 months postoperatively. Clinical outcomes included WOMAC, subjective IKDC, Pain VAS, Tegner activity score, and a self-designed sports questionnaire. Kellgren-Lawrence grading was used to assess progression of tibiofemoral OA. The Caton-Deschamps Index was used to assess differences in patellar height.

RESULTS

Twenty-seven patients (93 %) were available for 24-month follow-up. Eighty-one per cent of the patients were either satisfied or very satisfied with the overall outcome. Significant improvements in the WOMAC, subjective IKDC, and Pain VAS were seen in the overall patient cohort and in both subgroups. The median Tegner score and sports frequency showed a significant increase in the overall patient cohort and in group II. The number of sports disciplines increased significantly in both subgroups. No significant progression of tibiofemoral OA or changes in patellar height were observed.

CONCLUSION

Patellofemoral inlay resurfacing is an effective and safe procedure in patients with symptomatic patellofemoral OA. Significant improvements in functional scores and sports activity were found after both isolated and combined procedures.

LEVEL OF EVIDENCE

Prospective case series, Level III.

Are results of total knee arthroplasty for isolated patellofemoral OA as good as for medial compartment OA? A medium-term retrospective comparative study

PURPOSE

The aim of this study was to compare the results of isolated patellofemoral arthritis (IPFA) treated using a total knee arthroplasty (TKA) compared to the results of medial tibiofemoral arthritis treated with a TKA. We hypothesised that there would be no difference between functional outcomes for the two groups.

METHODS

Between 2003 and 2009, 32 TKAs were performed for IPFA (group I). Over this time period, a total of 813 primary TKAs were performed from which we identified a second group of patients who had undergone TKA for isolated medial tibiofemoral arthritis (group II: n = 32). These patients were matched based on age, sex, body mass index and average follow-up. The average age of patients in group I was 72.81 ± 6.6 years (59-83) and 71.97 ± 6.8 years in group II. The global International Knee Society (IKS) score was statistically significantly better in group I (114.72 ± 22 points) than in group II (84.9 ± 23.8). This difference was accounted for by better passive flexion, better walking distance and the absence of any coronal plane deformity.

RESULTS

A total of 29 patients from group I were reviewed at an average follow-up of 64.58 ± 23.4 months, and 30 patients in group II were reviewed at an average follow-up of 66.13 ± 23.9 months (three were lost to follow-up in group I and two in group II). At final follow-up, there was statistically no difference between the two groups IKS score (175.34 ± 19.26 in group I vs. 170.13 ± 24.14 for group II) or Hospital for Special Surgery patella score (89.31 ± 9.98 points for group I vs. 89.16 ± 11.45 points for group II). We found no significant radiological difference between the two groups including patella height and orientation on axial views.

CONCLUSIONS

The results of TKA for IPFA are as good as the results of TKA for isolated medial tibiofemoral arthritis with well-functioning prosthetic patellofemoral articulations. These results support our institutional preference for using TKA as treatment for IPFA in patients over 65-70 years old.

Evaluation of a minimally aggressive method of patellofemoral osteoarthritis treatment at 10 years minimum follow-up

BACKGROUND

Knee osteoarthritis mainly affecting the lateral facet of the patella, especially in young patients, is a definite challenge to the surgeon. Our purpose was to investigate the long-term outcome of a simple operation such as the partial lateral facetectomy on middle-aged to elderly patients with predominant lateral patellofemoral osteoarthritis.

METHODS

A retrospective, long-term study of 39 knees (28 females, mean aged at surgery 61yearsold) with a minimum follow-up of 10years was performed. Evaluations included preoperative and postoperative questionnaires, physical examinations, and radiographs.

RESULTS

The main outcomes included the initial anterior pain relief, with higher scores using the Knee Society Score (that improved in 84% of the knees), and the eventual failure of the technique, including percentage of patients that required secondary total knee replacement (30% of the knees).

CONCLUSION

Partial lateral facetectomy aiming to decrease the high pressure in the lateral facet of the patella confirmed frequent pain relief. This surgical procedure being minimally invasive, relatively simple, and effective in selected patients, is a valid early alternative to more complex operations and does not preclude further reconstructive surgery in case of disease progression.

Patellofemoral replacement

Isolated patellofemoral arthritis is a common condition and there are varying opinions on the most effective treatments. Non-operative and operative treatments have failed to demonstrate effective long-term treatment for those in an advanced stage of the condition. Newer designs and increased technology in patellofemoral replacement (PFR) have produced more consistent outcomes. This has led to a renewed enthusiasm for this procedure. Newer PFR prostheses have addressed the patellar maltracking issues plaguing some of the older designs. Short-term results with contemporary prostheses and new technology are described here.

Cite this article: Bone Joint J 2013;95-B, Supple A:124–8.

Computer-assisted navigation in patellofemoral arthroplasty: a new technique to improve rotational position of the trochlea

BACKGROUND

Maltracking or subluxation is one of the complications of patellofemoral arthroplasty.

QUESTIONS/PURPOSES

We questioned whether the computed navigation system can improve patellar tracking in patients with patellofemoral arthroplasty (PFA).

METHODS

Between 2007 and 2010 we performed 15 patellofemoral arthroplasties using the Ceraver PFA and navigation assistance. Fifteen other patients underwent surgery without navigation during the same period and acted as a control group. The rotation of the native trochlea as measured using the epicondylar line as a reference before surgery and the rotation of the trochlear component and the trochlear twist angle were assessed with computed tomography (CT) scan after surgery.

RESULTS

The mean follow-up was 3 years (range, 2-5 years). The group with navigation had no patellofemoral complications and better clinical scores. The group without navigation had abnormal patellofemoral tracking in 5 of the 15 patients. CT scan demonstrated excessive internal component rotation, as compared with patients without complications. This excessive internal rotation was proportional to the severity of the patellofemoral maltracking.

CONCLUSIONS

The short-term results suggest that navigation can lead to better trochlear rotation which, in our hands, is associated with fewer cases of patellar maltracking and better overall clinical scores.

Prospective clinical and radiological two-year results after patellofemoral arthroplasty using an implant with an asymmetric trochlea design

PURPOSE

The purpose was to prospectively evaluate the two-year results after implantation of the Journey PFJ(®) (Smith & Nephew, Andover, MA). The authors hypothesized that patellofemoral arthroplasty would result in improved outcomes after 24 months in patients treated with an isolated procedure as well as in patients demonstrating concomitant patellofemoral instability (PFI), which were treated with a combined surgical procedure.

METHODS

Patients were included between 02/2006 and 08/2008. According to the history and clinical findings, patients were grouped into group I with no history or clinical signs of PFI, and patients with concomitant PFI were assorted to group II. Patients were then treated with an isolated (group I) or a combined (group II) surgical procedure to additionally treat the PFI. Visual analogue scale (VAS), Lysholm score and WOMAC score were recorded preoperatively, 6, 12 and 24 months postoperatively. Patellar height was evaluated according to the index of Caton-Deschamps (CDI), and osteoarthritic changes were evaluated according to Kellgren and Lawrence.

RESULTS

A total of 25 patients were enrolled, of them three discontinued interventions and were excluded from final analysis. An isolated implantation of the Journey PFJ(®) was performed in 14 patients (group I) and a combined procedure in 8 (group II). Daily pain and clinical scores significantly improved at 6, 12 and 24 months compared to preoperative values (P < 0.05). Significant decrease (P = 0.02) of mean CDI could be noticed. Significant increase in tibiofemoral OA within the medial but not in the lateral tibiofemoral joint was assessed (P = 0.011; n.s.).

CONCLUSIONS

Patellofemoral arthroplasty using the Journey(®) PFJ for treatment of significant patellofemoral OA demonstrated improved clinical scores at the 2-year follow-up in both groups. Comparing the primary OA (I) and OA + instability (II) groups, patients with patellofemoral OA treated with a combined procedure for concomitant stabilization of patellofemoral instability may benefit more from such a combined procedure, than patients treated with an isolated procedure for treatment of isolated patellofemoral OA.

LEVEL OF EVIDENCE

Prospective case series, Level III.

Surgery for osteoarthritis of the knee

Although total knee replacement is an excellent treatment of end-stage osteoarthritis of the knee in the older (>65 years) population, many patients with less severe disease are significantly impacted by their symptoms and have failed to respond to less invasive treatment alternatives. For this group, there are several less invasive surgical alternatives, including arthroscopic meniscectomy, grafting of symptomatic areas of bone marrow lesions, unloading osteotomy, and unicompartmental knee replacement. Current total knee arthroplasty designs can be expected to survive 20 years or more in the older, less active population. New materials may extend that survivorship.

Approach to the active patient with chronic anterior knee pain

The diagnosis and management of chronic anterior knee pain in the active individual can be frustrating for both the patient and physician. Pain may be a result of a single traumatic event or, more commonly, repetitive overuse. "Anterior knee pain," "patellofemoral pain syndrome," and "chondromalacia" are terms that are often used interchangeably to describe multiple conditions that occur in the same anatomic region but that can have significantly different etiologies. Potential pain sources include connective or soft tissue irritation, intra-articular cartilage damage, mechanical irritation, nerve-mediated abnormalities, systemic conditions, or psychosocial issues. Patients with anterior knee pain often report pain during weightbearing activities that involve significant knee flexion, such as squatting, running, jumping, and walking up stairs. A detailed history and thorough physical examination can improve the differential diagnosis. Plain radiographs (anteroposterior, anteroposterior flexion, lateral, and axial views) can be ordered in severe or recalcitrant cases. Treatment is typically nonoperative and includes activity modification, nonsteroidal anti-inflammatory drugs, supervised physical therapy, orthotics, and footwear adjustment. Patients should be informed that it may take several months for symptoms to resolve. It is important for patients to be aware of and avoid aggravating activities that can cause symptom recurrence. Patients who are unresponsive to conservative treatment, or those who have an underlying systemic condition, should be referred to an orthopedic surgeon or an appropriate medical specialist.

Analysis of the center of pressure displacement, ground reaction force and muscular activity during step exercises

Anterior Knee Pain (AKP) is considered as one of the most common, yet misunderstood, knee pathologies. The aim of this study was to evaluate the displacement area of the center of pressure, Ground Reaction Force (GRF), and the electromyography activity of the hip and the quadriceps muscles in healthy and AKP individuals during the step-up and step-down exercises. Both groups (Control group and AKP group) were composed of 15 volunteers submitted to the exercises on a force plate. The AKP group presented greater displacement area of the center of pressure for all the situations evaluated than the Control group (p<0.05), as well as a lesser magnitude of the GRF during the step-down exercise. The AKP group presented lower electromyography activity than the Control group in all situations evaluated. AKP individuals do not have muscle imbalances; they present a lower electromyography activity of the stabilizing muscles of the patella and hip and show greater instability in activities such as step up and down compared to normal subjects.

The patellar thinning osteotomy in patellofemoral arthritis: four to 18 years' follow-up

Isolated patellofemoral osteoarthritis can be a disabling disease. When conservative treatment fails, surgical options can be unpredictable and may be considered too aggressive for middle-aged and active people. We analysed the clinical and radiological results of a new coronal osteotomy involving thinning of the patella in a selected group of patients with isolated patellofemoral osteoarthritis. Since 1991, 31 patients (35 knees) have been treated, of whom 34 were available for follow-up at a mean of 9.1 years. The Knee Society Score, the Patellar score and the Short-form-36 questionnaire were used for clinical evaluation. We also examined the radiological features to confirm bone consolidation and assess the progression of osteoarthritis. A significant improvement in the functional scores and radiological parameters was noted. All patients except one were satisfied with the operation. Radiological progression of the patellofemoral osteoarthritis was slowed but radiological femorotibial osteoarthritis progressed in 23 (65%) cases, with a total knee replacement becoming necessary in four cases without technical problems in resurfacing the patella. We compared the results with other forms of surgical treatment reported in the literature. This treatment offers good clinical and radiological results, presenting an alternative method of managing patellofemoral osteoarthritis.

Long-term outcomes of patellofemoral arthroplasty

The purpose of this study was to correlate the long-term survival of patellofemoral arthroplasty with primary diagnosis, age, sex, and body mass index. One hundred eighty-five consecutive Richards type II patellofemoral arthroplasties were performed in 161 patients with isolated patellofemoral osteoarthritis. Diagnoses included primary patellofemoral osteoarthritis, posttraumatic patellofemoral osteoarthritis, and patellofemoral osteoarthritis with a previous realignment procedure for patellar subluxation or trochlear dysplasia. Median time to follow-up was 13.3 (range, 2.0-30.6) years. Patellofemoral arthroplasty survival was 84% at 10 years and 69% at 20 years. Primary diagnosis, sex, or age at patellofemoral arthroplasty did not significantly affect the rate of revision (P=.35, P=.24, and P=.65, respectively). The rate of revision in obese patients (body mass index>30 kg/m2) was higher than that in nonobese patients (P=.02).

Strategies for articular cartilage lesion repair and functional restoration

Injury of articular cartilage due to trauma or pathological conditions is the major cause of disability worldwide, especially in North America. The increasing number of patients suffering from joint-related conditions leads to a concomitant increase in the economic burden. In this review article, we focus on strategies to repair and replace knee joint cartilage, since knee-associated disabilities are more prevalent than any other joint. Because of inadequacies associated with widely used approaches, the orthopedic community has an increasing tendency to develop biological strategies, which include transplantation of autologous (i.e., mosaicplasty) or allogeneic osteochondral grafts, autologous chondrocytes (autologous chondrocyte transplantation), or tissue-engineered cartilage substitutes. Tissue-engineered cartilage constructs represent a highly promising treatment option for knee injury as they mimic the biomechanical environment of the native cartilage and have superior integration capabilities. Currently, a wide range of tissue-engineering-based strategies are established and investigated clinically as an alternative to the routinely used techniques (i.e., knee replacement and autologous chondrocyte transplantation). Tissue-engineering-based strategies include implantation of autologous chondrocytes in combination with collagen I, collagen I/III (matrix-induced autologous chondrocyte implantation), HYAFF 11 (Hyalograft C), and fibrin glue (Tissucol) or implantation of minced cartilage in combination with copolymers of polyglycolic acid along with polycaprolactone (cartilage autograft implantation system), and fibrin glue (DeNovo NT graft). Tissue-engineered cartilage replacements show better clinical outcomes in the short term, and with advances that have been made in orthopedics they can be introduced arthroscopically in a minimally invasive fashion. Thus, the future is bright for this innovative approach to restore function.

Tantalum is a good bone graft substitute in tibial tubercle advancement

BACKGROUND

Porous tantalum is reportedly a good substitute for structural bone graft in several applications. So far, its use has not been reported in tibial tuberosity anteriorization (TTA) for treatment of isolated degenerative chondral lesions of the patellofemoral joint.

QUESTIONS/PURPOSES

We asked whether the use of this material would produce similar standardized functional scores, pain (VAS), fusion rates, complications, and patient satisfaction to those for bone graft.

PATIENTS AND METHODS

We performed a randomized, controlled trial in 101 patients (108 knees) scheduled for TTA comparing a porous tantalum implant (57 knees) with an autologous local tibial bone graft (51 knees). The minimum followup was 5 years (mean, 6.2 years; range, 5-8 years).

RESULTS

At the last followup, clinical scores, fusion rates, and maintenance of the anteriorization either were better or similar for the TTA using the tantalum implant depending on the respective parameter. The operative technique was easier and shorter with the tantalum device. Complication and failure rates were greater using bone graft. Patient satisfaction was greater using the tantalum implant.

CONCLUSIONS

Porous tantalum provided a reasonable alternative to bone graft in TTA.

LEVEL OF EVIDENCE

Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Sports after knee arthroplasty: partial versus total knee arthroplasty

Osteoarthritis becomes more prevalent with increasing age, and currently is occurring more frequently in the "baby boomer" generation (ages 44-66 years). However, many individuals may be reluctant to undergo arthroplasty procedures because potential activity limitations. Thus, physicians must consider each patient's history and desired activity level after treatment. Osteoarthritis treatments include nonoperative measures such as weight reduction, injections, and nonsteroidal anti-inflammatory drugs, as well as operative options, including partial and total knee arthroplasty. Each treatment type will vary in its impact on activity levels. If arthroplasty is required, patients must be cautioned to minimize component overload, which may result in polyethylene wear and loosening; however, cardiopulmonary fitness and general conditioning benefits of activity can be maintained.

Surgical options for patients with osteoarthritis of the knee

Osteoarthritis (OA) of the knee is a progressive disease that ultimately damages the entire joint. Knee OA should initially be treated conservatively, but surgery should be considered if symptoms persist. Surgical treatments for knee OA include arthroscopy, osteotomy and knee arthroplasty; determining which of these procedures is most appropriate will depend on several factors, including the location and severity of OA damage, patient characteristics and risk factors. Arthroscopic lavage and debridement do not alter disease progression, and should not be used as a routine treatment for the osteoarthritic knee. Bone marrow stimulation techniques such as microfracture are primarily used to treat focal chondral defects; the evidence for the use of these techniques for knee OA remains unclear. The goal of osteotomy for unicompartmental knee OA is to transfer the weight load from the damaged compartment to undamaged areas, delaying the need for joint replacement. This procedure should be considered in young and active patients who are not suitable candidates for knee arthroplasty. For patients with severe OA, total knee arthroplasty can be a safe, rewarding and cost-effective treatment. In selected patients with isolated medial or patellofemoral OA, unicompartmental knee arthroplasty and patellofemoral replacement, respectively, can be successful.

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.

Surgery for osteoarthritis of the knee

The role of surgical treatment in osteoarthritis of the knee continues to evolve. The indications for arthroscopy have narrowed. Orthopedic surgeons continue to explore options less invasive than total knee replacement for isolated unicompartmental arthritis of the knee joint. In addition to arthroscopy, this article discusses the merits and drawbacks of and indications for osteotomy, interpositional arthroscopy, patellofemoral replacements, and emerging technologies for total knee replacements.

Surgery for osteoarthritis of the knee

The role of surgical treatment in osteoarthritis of the knee continues to evolve. The indications for arthroscopy have narrowed. Orthopedic surgeons continue to explore options less invasive than total knee replacement for isolated unicompartmental arthritis of the knee joint. In addition to arthroscopy, this article discusses the merits and drawbacks of and indications for osteotomy, interpositional arthroscopy, patellofemoral replacements, and emerging technologies for total knee replacements.

[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.

Prescribing quality patellofemoral rehabilitation before advocating operative care

In this article we discuss causes of patellofemoral dysfunction, the treatment algorithm of nonsurgical therapy modalities, and what constitutes a quality rehabilitation protocol for a patient with patellofemoral dysfunction.

Focal anatomic patellofemoral inlay resurfacing: theoretic basis, surgical technique, and case reports

Prosthetic patellofemoral inlay resurfacing is a novel treatment concept for degenerative and focal arthrosis of the patellofemoral joint. The theoretic basis of this type of arthroplasty entails recreating ambient anatomy based upon intraoperative topographic mapping. The implant is intrinsically stable by virtue of the inset position relative to the surrounding joint surface. Articular resurfacing, rather than traditional replacement arthroplasty, represents an extension of the concepts of biologic joint restoration. Early results have shown great efficacy. This surgery may be appropriate for a wide variety of indications, including younger patients and those with focal patellofemoral disease concurrent with morphologic or alignment abnormalities.

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.

Isolated patellofemoral osteoarthritis

Isolated patellofemoral osteoarthritis is now recognised to be more common than previously thought. The features and management are reviewed, including the various surgical options in symptomatic patients. The evidence base for managing patellofemoral osteoarthritis is behind that for the tibiofemoral joint. All treatments are based on uncontrolled observational case series, typically retrospectively reviewed. Fortunately the majority of patients with isolated patellofemoral degenerative changes do not need surgical treatment. Those who are symptomatic can usually be successfully treated with weight loss and quadriceps strengthening exercises.