The likelihood of healing of osteochondritis dissecans decreases with skeletal maturity and there are theories that abnormal biomechanical forces contribute to the development and progression of these lesions.
To characterize, according to regional skeletal maturity, the morphology and alignment indices of the patellofemoral joint on MRI in patients with patellar osteochondritis dissecans.
MRI examinations of patients with patellar osteochondritis dissecans obtained between January 2008 and May 2023 were retrospectively reviewed to determine regional skeletal maturity, osteochondritis dissecans lesion size and location, patellar and trochlear morphology (Wiberg/Dejour classifications), and to calculate trochlear sulcus angles, trochlear depth index, lateral trochlear inclination, Insall-Salvati index, Caton-Deschamps index, patellar tendon-lateral trochlear ridge, and tibial tubercle-trochlear groove distances. Values were compared between skeletally immature and mature groups.
Sixty-eight children (22 girls, 46 boys, age: 14.0 ± 1.7 years) yielded 74 knees with patellar osteochondritis dissecans lesions, 14 (19%) of which were skeletally mature. The most common anatomic location was over the central patella [median ridge (34/74 - 46%) on the axial images and over the middle third (45/74 - 61%) on the sagittal images]. Overall, mean trochlear sulcus angle (high, 151 ± 11°), trochlear depth index (low, 2.8 ± 1.4 mm), and Insall-Salvati index (borderline, 1.3 ± 0.1) were abnormal for the entire sample. Skeletally mature knees were significantly more likely to have higher (more dysplastic) Dejour types when compared to skeletally immature knees (p < 0.01). Knees in the mature group, compared to immature, had significantly more abnormal mean lateral trochlear inclination (15 ± 8° vs. 19 ± 6°, p = 0.03) and patellar tendon-lateral trochlear ridge distance (5.55 ± 4.31 mm vs. 2.89 ± 4.69 mm, p = 0.04). Half of the knees had ≥ 4 abnormal features that predispose to patellofemoral maltracking; mature knees were significantly (p = 0.02) more likely to have a higher number of abnormal features (> 6 features, 7/14, 50.0%) versus immature knees (0-3 features, 33/60, 55.0%).
In children with patellar osteochondritis dissecans, abnormal patellofemoral morphology and alignment indices were common in all patients and more severe in mature knees.

BACKGROUND: The aim of this study was to report a long-term follow-up of patients treated with autologous matrix-induced chondrogenesis (AMIC) for full-thickness chondral and osteochondral defects of the femoral condyle or patella combined with the correction of lower limb malalignment or patellar tracking if indicated.
METHODS: Thirty-three patients (thirty-four knees) were treated surgically for chondral and osteochondral cartilage defects of the knee joint. Regarding the origin of the lesion, patients were divided into three groups. Chondral lesions were observed in the patella (cP group) in fifteen patients, whereas eight patients demonstrated a femoral condylar location (cF group). Eleven patients presented with osteochondritis dissecans of the femur (ocF group). Associated procedures involving realignment of the patella, osteotomy around the knee, or cancellous bone grafting were performed when necessary. The mean size of the lesions was 2.8 ± 1.6 cm2, and the mean patient age was 37.1 ± 11.9 years. To evaluate the clinical outcomes, the Lysholm score and the VAS pain score were imposed, as well as the reoperation rate.
RESULTS: After an average of 9.3 ± 1 years, follow-up was completed in 79% of the patients. Two patients from the cohort received a total knee prosthesis. The primary outcome measures (Lysolm and VAS pain) at 9-year follow-up were 85 ± 13 for the Lysholm score and 1.9 ± 1.6 for the VAS score in the entire analyzed population. Compared to the preoperative values (Lysholm 56 ± 19, VAS 5.8 ± 2.4) and the 2-year results (Lysholm 85 ± 16, VAS 2.0 ± 2.1), there was significant improvement in the first 2 years after intervention and a stable course in the long-term observation. The same was observed in the cP and ocF subgroups, whereas patients of the cF group showed even further improvement.
CONCLUSIONS: AMIC showed durable results in aligned knees. The favorable outcome was maintained after an average of 9 years when malalignment of the lower limb and patellar maltracking were corrected. Such data are particularly encouraging for young adult patients who may benefit from a procedure that circumvents early arthroplasty.

OBJECTIVE. The purpose of this study is to clarify which imaging parameters of patellofemoral maltracking are associated with superolateral Hoffa fat pad (SHFP) edema. MATERIALS AND METHODS. A systematic search of the MEDLINE, Embase, and Cochrane Library databases was performed to identify studies evaluating the relationship between SHFP edema and patellofemoral maltracking. Parameters for assessing patellofemoral maltracking on MRI were reviewed for each study. Two reviewers performed study selection, methodologic quality assessment, and data extraction. RESULTS. Nine studies were eligible for inclusion in the present study. From the included studies, nine parameters assessing patellofemoral maltracking were analyzed: lateral patellofemoral angle, patellar tilt, patellar lateralization, trochlear depth, sulcus depth, sulcus angle, lateral trochlear inclination, distance between the tibial tuberosity and trochlear groove, and the Insall-Salvati ratio. Patients with SHFP edema had greater patellar tilt (standardized mean difference, 0.89°; 95% CI, 0.38-1.40°; p = 0.0006), greater patellar lateralization (standardized mean difference, 0.78 mm; 95% CI, 0.21-1.36 mm; p = 0.008), greater distance between the tibial tuberosity and trochlear groove (standardized mean difference, 0.96 mm; 95% CI, 0.48-1.44 mm; p < 0.0001), and higher Insall-Salvati ratio (standardized mean difference, 1.94; 95% CI, 1.29-2.60; p < 0.00001) than patients without SHFP edema. CONCLUSION. Patellofemoral maltracking imaging parameters, such as a more laterally displaced patella, greater TTTG distance, and patella alta, are correlated with SHFP edema.

OBJECTIVE: Anterior knee pain or patellofemoral instability is common symptom of patellofemoral dysbalance or maltracking. Tibial torsional deformities can be the reason of this pathology. After appropriate diagnostic investigation, the treatment of choice is a torsional osteotomy. This study addresses the diagnostic investigation, treatment, and the outcome of torsional osteotomies of the tibia. Does this treatment result in patellofemoral stability and provide pain relief?
METHODS: Forty-nine tibial torsional osteotomies were included. The major symptoms were patellofemoral instability in 19 cases and anterior knee pain in 42 cases. In addition to clinical and radiographic analysis, a torsional angle CT scan was performed pre-operatively. A visual analog scale (VAS), the Japanese Knee Society score, the Tegner activity score, and the Lysholm score were assessed pre-operatively and at the 42-month follow-up.
RESULTS: Mean tibial external torsion was 47.4° (SD 5.41; range 37°-66°; standard value 34°). Surgical treatment consisted of an acute supratuberositary tibial internal torsional osteotomy (mean 10.8°; SD 3.01°; range 5°-18°). At the follow-up investigation, the Tegner activity score was increased 0.4 points (p value 0.014) from 3.9 (SD 1.33; range 2-7) to 4.3 (SD 1.25; range 0-7). The Lysholm score increased 26 points (SD 16.32; p value 0.001) from 66 (SD 14.94; range 32-94) to 92 (SD 9.29; range 70-100) and the Japanese Knee Society score increased 18 points (SD 14.70; p value 0.001) from 72 (SD 13.72, range 49-100) to 90 (SD 9.85, range 60-100). VAS was reduced 3.4 points (SD 2.89; p value 0.001) from 5.7 (SD 2.78; range 0-10) to 2.3 (SD 1.83; range 0-7). As regards patellofemoral instability, no redislocation occurred in the follow-up period.
CONCLUSIONS: The results of this study show that in cases of tibial maltorsion, a torsional osteotomy can lead to patellofemoral stability and pain relief, and should be considered as a treatment option. The improved clinical scores in the present investigation show the value of the procedure. Level of evidence Level IV.

Various pathologies of the hip or knee, such as patellofemoral malalignment or femoroacetabular impingement may be caused by a femoral torsional deformity. When diagnosed and analyzed, it is treated by femoral torsional osteotomy. Thirty femoral torsional osteotomies in 25 patients were included, the principal symptoms were patellar dislocation in 15 patients, anterior knee pain in 17, and femoroacetabular impingement in two. A computed-tomography-based measurement of the torsional angle was performed in all patients. Japanese Knee Society score, Tegner activity score, Lysholm score, and visual analog scale score were determined before surgery and at follow-up after 41 (6-113) months. Femoral internal torsion was on average 40.9° (29° - 66°; normal 24°). Surgical treatment consisted of a femoral external torsional osteotomy of on average 13.8° (5° - 26°). Tegner activity score increased non-significantly (p-value 0.326) from 3.57 to 3.71. Japanese Knee Society score improved significantly from 72 to 87 (p-value 0.004) while Lysholm score rose significantly from 66 to 84 points (p-value 0.004). Pain relief was demonstrated by a significant decrease in the VAS score from 5.6 to 2.4 (p-value 0.007). No further patellar dislocation was reported. Torsional deformities of the femur frequently cause symptoms in the knee or hip joint. After thorough assessment and diagnostic investigation, a femoral external torsional osteotomy provides significant pain relief as well as patellofemoral stability.

BACKGROUND: Patellofemoral pain (PFP) is a common condition and often presents without evidence of arthritis on radiographs. Magnetic resonance imaging (MRI) has shown good correlation between T1ρ and T2 relaxation times and changes in the cartilage matrix, but as of yet, there are limited data in the literature utilizing these modalities to evaluate the patellofemoral joint.
OBJECTIVE: Patients with PFP and patellar tilt will show longer T1ρ relaxation times in the lateral facets of their patella but no difference in T2 values.
METHODS: Cross-sectional study; Level of evidence, 3.
METHODS: A total of 20 patients aged 18 to 45 years with anterior knee pain, patellar tilt, and no evidence of osteoarthritis were identified and consented to undergo MRI including axial T1ρ and T2 relaxation time mapping sequences. Knee cartilage was segmented on spoiled gradient recalled acquisition in steady state (SPGR) images using a spline-based algorithm. These results were then compared with those of 10 age-matched controls.
RESULTS: The mean T1ρ values of the lateral facets were significantly elevated in patients with PFP compared with controls (46.33 ± 4.92 ms vs. 42.32 ± 3.67 ms, respectively; P = .031), while no significant difference was observed in the medial facets (42.20 ± 5.55 ms vs. 41.42 ± 4.09 ms, respectively; P = .69). Significantly higher mean T1ρ values were noted in the lateral facets of the patients with PFP (46.33 ms) compared with the medial facets (42.20 ms) (P = .0001), while no significant differences in T1ρ values were observed between the medial and lateral facets of the controls (P = .502). No significant differences were noted in T2 relaxation times. A high correlation was noted between the mean T1ρ values of the whole patella of patients with PFP and the degree of patellar tilt (r = 0.72).
CONCLUSIONS: There were significantly higher T1ρ values in the lateral facets of patients with PFP and patellar tilt that were not seen in control patients. These higher values approach the numbers seen in patients with early osteoarthritis.

BACKGROUND: Ten to fifteen percent of knee arthritis is reported to be isolated patellofemoral arthritis. Total knee arthroplasty is not recommended for isolated patella femoral arthritis particularly in young patients. We present the retrospective review of 45 consecutive patellofemoral replacements performed in 41 such patients, between June 2002 and January 2007.
METHODS: All patients were operated by single surgeon (SM) or under his supervision. All forty five patients had minimum three year followup and had the data collected prospectively. No patient was lost to followup. This data was later collated by review of notes, radiographs, and a clinical followup. The patients were assessed using knee function score and Melbourne patellofemoral score.
RESULTS: The average followup was 4.5 years. The preoperative average Melbourne (Bartlett) score was 10 (range 5-21). Preoperative knee functional score averaged 57 (range 23-95). The average range of movement was 116° (range 100°-140°). Postoperatively, the average Melbourne knee score improved to 25 (range 11-30), while the knee function score was 85 (range 28 - 100). The difference was statistically significant (P<0.05). Eighty-five percent rated the result as good or excellent, while 12% rated it as fair. Five percent thought the result was poor. The most common complaint was clicking at 40° of flexion (n=7). Six patients underwent arthroscopic lateral release, which improved the symptoms in four patients. Two knees were revised one due to progression of tibiofemoral arthritis and the other due to persistent clicking, yielding a survival rate of 95.6% at an average five year followup.
CONCLUSIONS: The Avon patellofemoral joint replacement provides predictably good results and excellent survivorship in the medium term, for isolated patellofemoral arthritis. However, progression of tibiofemoral arthritis remains unpredictable and therefore patient selection is crucial to ensure success. Clicking remains a potential problem and can compromise the postoperative results in upto 15% of the cases.