A reliable Q angle measurement using a standardized protocol.

BACKGROUND: Studies have shown that Q angle measurements were unreliable. Imaging studies have largely replaced the Q angle for measuring tibial tubercle lateralization. Creating a standardized protocol to measure the Q angle, with normative values, would provide a reliable reference without expensive imaging techniques. METHODS: Thirty men and 27 women without history of knee problems or family history of dislocating kneecaps were subjects. Exclusion criteria were: patellofemoral abnormalities upon examination. We measured the Q angles of both knees using a standardized protocol and a long-armed goniometer. These data were analyzed to calculate normative values. RESULTS: For all subjects, the mean was 14.8° (≈15°), 95% confidence interval (CI): ±5.4°. The male mean was 13.5°, 95% CI: ±5.2°. The female mean was 15.9°, 95% CI: ±4.8°. There was no significant difference between the right and left knees of the males (p = 0.52), nor of the females (p = 0.62), Beta = 0.14. The 2.4° difference between male and female means was due to the average height difference between the men and women. CONCLUSIONS: This study provides a standardized Q angle measurement protocol to assess tibial tubercle lateralization at a patient's first encounter (and intra-operatively) without resorting to expensive imaging studies. These values provide a reliable reference for clinical comparison, and will allow all clinicians and sports medicine personnel to assess tubercle lateralization with reliability and validity. When using this protocol, the term "Standard Q Angle" (SQA) should be used, to avoid confusion with other measurement protocols.

The Diagnosis and Initial Treatment of Patellofemoral Disorders.

Our purpose is to provide simple guidelines for the diagnosis and early care of patellofemoral disorders. Any clinician who treats knee problems, including family practitioners, rheumatologists, orthopedic surgeons, or physical therapists, must know how to make the correct diagnosis, or at least a presumptive diagnosis, at the initial visit. This can avoid unneeded and costly tests, ineffective treatment, and even damaging exercises and unnecessary surgery. The diagnosis of patellofemoral disorders is confusing because they can have many causes. That is, the etiology of patellofemoral disorders is multifactorial. To dispel this confusion and simplify the process, we use a clinical classification based on etiology. Within that framework are 7 key abnormalities or factors that can cause both patellofemoral pain and instability: vastus medialis obliquus deficiency, medial patellofemoral ligament laxity, lateral retinaculum tightness, increased quadriceps angle, hip abductor weakness, patella alta, and trochlear dysplasia. At the initial evaluation, the clinician can assess for these abnormalities through history-taking, physical examination, and standard radiography. Any abnormalities identified, along with their severity, can be used to arrive at a diagnosis, or a presumptive diagnosis, and begin early nonoperative treatment. The clinician does not need magnetic resonance imaging at this point, unless a presumptive diagnosis cannot be made or a more complex problem is suggested.

Multidirectional Tibial Tubercle Transfer Technique: Rationale and Biomechanical Investigation.

This study describes a new surgical technique to transfer the tibial tubercle, explains the rationale for its development, and reports the results of initial biomechanical testing. The design goals were to create a tibial tubercle osteotomy that would provide equivalent or better initial fixation compared with traditional techniques, yet would be more flexible, reproducible, accurate, less invasive, and safer. The results of the biomechanical analysis suggest that initial fixation with this novel tubercle transfer technique is as strong as traditional Elmslie-Trillat and anteromedialization procedures.

Iatrogenic Medial Patellar Instability: An Avoidable Injury.

Iatrogenic medial patellar instability is a specific condition that frequently causes incapacitating anterior knee pain, severe disability, and serious psychological problems. The diagnosis should be suspected in a patient who has undergone previous patellar realignment surgery that has made the pain worse. The diagnosis can be established by physical examination and simple therapeutic tests (e.g., "reverse" McConnell taping) and confirmed by imaging techniques. This iatrogenic condition should no longer exist and could almost be eliminated by avoiding over-release of the lateral retinaculum.

Results of isolated lateral retinacular reconstruction for iatrogenic medial patellar instability.

PURPOSE: The aim of this study was to assess the outcomes of an isolated lateral retinaculum reconstruction for iatrogenic medial patellar instability (IMPI) in patients with continued pain after failed lateral retinacular release (LRR), including associated psychometric analysis. METHODS: Pain was assessed using the visual analog scale (VAS) and disability was determined with the Lysholm scale. Psychological variables such as anxiety, depression, catastrophizing, and fear-of-movement beliefs were studied by using self-administered psychometric questionnaires. RESULTS: All 17 patients (13 women and 4 men) in this retrospective study had undergone LRR previously for anterior knee pain or lateral patellar instability. Four patients had undergone LRR plus proximal (Insall) realignment, and one had undergone LRR plus a medial tibial tubercle transfer. After their procedures, all had disabling symptoms. All patients underwent reconstructive surgery for IMPI. At a minimum follow-up of 2 years (range, 2 to 8 years), the mean preoperative VAS score was 7.6 (range, 5 to 9) and improved to 1.9 (range, 0 to 8) at the time of final follow-up (P < .001). The mean preoperative Lysholm score was 36.4 (range, 20 to 55), and the knee was described as bad (<65 points) in all cases. Postoperatively, it improved to 86.1 (range, 70 to 94) at final follow-up (P < .001). Before surgery, 4 patients (24%) had the clinical criteria for depression, 10 (59%) had anxiety, 7 (41%) had "catastrophizing" ideas concerning pain, and all (100%) had kinesiophobia (fear of movement). After surgery, none of the patients had depression or anxiety, none had catastrophizing ideation, and only 53% had kinesiophobia. CONCLUSIONS: Reconstruction of the deep transverse layer of the lateral retinaculum (LR) using a central strip of the iliotibial band for IMPI in patients with continued pain after failed LRR can successfully treat these severely disabled patients. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Prevalence of abnormal patellofemoral congruence in elite American football players and association with quadriceps isokinetic testing.

Abnormal patellofemoral joint alignment has been discussed as a potential risk factor for patellofemoral disorders and can impact the longevity of any elite athlete's career. The prevalence of abnormal patellofemoral congruence in elite American football athletes is similar to the general population and does not have a relationship with quadriceps isokinetic testing. A total of 125 athletes (220 knees) from the 2011 National Football League (NFL) Combine database who had radiographic and isokinetic studies were reviewed. Congruence angles (CA) and lateral patellofemoral angles (LPA) were calculated on a Merchant radiographic view. Isokinetic testing was used to determine quadriceps-to-hamstring strength (Q/H) ratio and side-to-side deficits. The relationships between abnormal CA and LPA with Q/H ratios, side-to-side deficits, and body mass index (BMI) were examined in separate logistic regression models. A Chi-square test was used to examine the association between CA and player position. Of all, 26.8% of the knees (95% CI: 21.1-33.2%) had an abnormal CA. Knees with normal CA (n = 161) did not significantly differ from those with an abnormal CA (n = 59) in Q/H ratios (mean: 0.699 vs. 0.728, p = 0.19) or side-to-side quadriceps deficits (mean: 4.0 vs. 1.24, p = 0.45). For each point increase in BMI, the odds ratio (OR) of abnormal congruence increased by 11.4% (p = 0.002). Of all the knees, 4.1% (95% CI: 1.9-7.6%) had an abnormal LPA, and this was not associated with Q/H ratios (p = 0.13). For each point increase in BMI, the odds of abnormal LPA increased by 16% (p = 0.036). CA abnormality had much higher odds of having an abnormal LPA (OR: 5.96, p = 0.014). We found that abnormal patellofemoral radiographic alignment in elite American football players is relatively common and there was no association with isokinetic testing.

The female knee: anatomic variations and the female-specific total knee design.

UNLABELLED: The concept and need for a gender-specific or female-specific total knee prosthesis have generated interest and discussion in the orthopaedic community and the general public. This concept relies on the assumption of a need for such a design and the opinion that there are major anatomic differences between male and female knees. Most of the information regarding this subject has been disseminated through print and Internet advertisements, and through direct-to-patient television and magazine promotions. These sources and a recent article in a peer-reviewed journal, which support the need for a female-specific implant design, have proposed three gender-based anatomic differences: (1) an increased Q angle, (2) less prominence of the anterior medial and anterior lateral femoral condyles, and (3) reduced medial-lateral to anterior-posterior femoral condylar aspect ratio. We examined the peer-reviewed literature to determine whether women have had worse results than men after traditional TKAs. We found women have equal or better results than men. In addition, we reviewed the evidence presented to support these three anatomic differences. We conclude the first two proposed differences do not exist, and the third is so small that it likely has no clinical effect. LEVEL OF EVIDENCE: Level IV, systematic review. See the Guidelines for Authors for a complete description of levels of evidence.

A modular prosthesis for patellofemoral arthroplasty: design and initial results.

UNLABELLED: This study was designed to determine if a new and modular prosthesis for patellofemoral arthroplasty would produce results at least as good as those reported for other designs, while simultaneously eliminating the risks of patellar revision should total knee arthroplasty be needed in the future. Another issue was its suitability for the older patient with isolated patellofemoral arthritis in order to avoid destruction of the normal femoro-tibial compartments involved in total knee arthroplasty. Finally, I sought information about the safety and longevity of this prosthesis when used for patellofemoral arthroplasty in severely disabled patients too young to be considered for total knee replacement. From a cohort of 16 patients (8 studied retrospectively and 8 prospectively), aged 26 to 81 years, and followed up for 2.75-6.25 years, 15 (94%) rated their results excellent or good using the Activities of Daily Living Scale. These results are better than previously reported for other prosthetic designs. To date, no patient in this study group has required conversion to a total knee arthroplasty. The design has proven safe for use in both the older and younger patient, but longer followup will be needed to assess greater longevity. LEVEL OF EVIDENCE: Therapeutic Study, Level IV-8 (case series--no, or historical control group). See the Guidelines for Authors for a complete description of levels of evidence.

Early results with a total patellofemoral joint replacement arthroplasty prosthesis.

This report concerns a new prosthesis for total patellofemoral joint replacement. Patients severely disabled due to isolated patellofemoral arthritis in whom all other treatment options had been tried and failed, or were not indicated, became candidates for this surgery. Fifteen patients met these criteria and were followed an average of 3.75 years (range: 2.25-5.5 years). Using the Activities of Daily Living Scale, 14 of 15 patients (93%) had excellent (85%-100%) or good (75%-84%) results, and 1 was fair (65%-74%).