A novel clinical test for assessing patellar cartilage changes and its correlation with magnetic resonance imaging and arthroscopy.

Controversy still exists regarding the best clinical assessment test for chondromalacia patellae (CMP). Our study aims to evaluate the specificity and sensitivity of a novel clinical test for CMP, the "Patella Slide Test" (PST) against the findings of magnetic resonance imaging (MRI) and arthroscopy. We included 221 consecutive patients planned for elective knee arthroscopic surgery. An MRI scan of the symptomatic knee was performed prior to surgery. On the day of surgery, each patient was examined using the PST followed by a knee arthroscopy to assess the quality of the chondral surfaces of the patellofemoral joint. The MRI and PST results were compared against the arthroscopic findings that served as the gold standard. The PST (0.89) was statistically more sensitive than MRI (0.67) in diagnosing CMP. The PST (0.89) also had a greater negative predictive value (NPV) than MRI (0.74). However, MRI (0.94) was more specific than the PST (0.85). The differences in accuracy and positive predictive value of the PST versus MRI were not statically significant. In conclusion, the PST shows high sensitivity and has a greater NPV than MRI as a clinical test for diagnosing CMP.

Does the grading of chondromalacia patellae influence anterior knee pain following total knee arthroplasty without patellar resurfacing?

OBJECTIVES: The influence of chondromalacia patellae (CMP) on post-operative anterior knee pain (AKP) following total knee arthroplasty (TKA) remains controversial, and few studies have focused on the relationship between them. The purpose of this study was to determine whether different CMP grades affect the incidence of AKP after TKA without patellar resurfacing. METHODS: We performed a retrospective analysis of prospectively collected data on 290 TKAs with the use of the low contact stress mobile-bearing prosthesis, without patellar resurfacing in 290 patients from February 2009 to January 2013. Patients were assessed by the Outerbridge classification for CMP, visual analog scale for AKP, the Knee Society clinical scoring system of knee score (KS), function score (FS), the patellar score (PS) for clinical function, and patients' satisfaction. RESULTS: The intra-operative grading of CMP: grade I in 30 patients, grade II in 68 patients, grade III in 97 patients, and grade IV in 95 patients. The incidence of AKP at 36-month follow-up was 10.3% (30/290). No statistical difference was detected among the different CMP grades in terms of the incidence of AKP (p = 0.995), patients' satisfaction (p = 0.832), KS (p = 0.228), FS (p = 0.713), and PS (p = 0.119) at 36-month follow-up. CONCLUSIONS: The findings may suggest no relevant influence of CMP grading on the incidence of AKP after TKA without patellar resurfacing.

Tibial Tubercle Osteotomy for Patellar Chondral Pathology in an Active United States Military Population.

PURPOSE: To quantify rates of perioperative complications, secondary surgery, subjective pain relief, and knee-related medical separation in an active military population after a tibial tubercle osteotomy (TTO) for the primary indication of chondral pathology. METHODS: All active-duty service members undergoing TTO with a minimum of 2 years' follow-up were isolated from the Military Health System database. The exclusion criteria were patients with patellar instability, other periarticular osteotomy, and insufficient follow-up. Demographic information and surgical characteristics were abstracted from the electronic health record and correlated with improvement in pain and medical discharge from the military. RESULTS: A total of 76 patients (86 knees) who underwent TTO for patellofemoral chondromalacia were identified with a mean age of 32.3 years. Major and minor complications occurred in four patients (4.7%) and three patients (3.5%), respectively, and the overall improvement in the visual analog scale score after TTO was 1.5 (P < .0001). At a mean follow-up of 3.4 years (range, 2.0 to 7.3 years), 37% of patients were unable to return to modified military activity because of knee-related limitations. Junior military rank group (P = .0084), age younger than 35 years (P = .0031), bilateral TTO procedures (P = .0294), and tobacco use (P = .0218; odds ratio, 3.29; 95% confidence interval, 1.19 to 9.12) were risk factors for medical separation, whereas absence of concomitant chondral repair (P = .5408), previous knee procedures (P = .9674), and greater occupational demands (P = .7062) were not. CONCLUSIONS: At short-term to midterm follow-up, 63% of patients successfully returned to military function with a low rate of perioperative complications (8%). The postoperative decrease in pain after TTO is of unknown clinical significance. Age younger than 35 years, junior military rank, bilateral TTO procedures, and tobacco use were significant risk factors for medical separation, whereas absence of concomitant cartilage repair, previous knee procedures, and lower occupational demands were not associated with improved visual analog scale scores or prevention of knee-related medical discharge. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Revision cartilage cell transplantation for failed autologous chondrocyte transplantation in chronic osteochondral defects of the knee.

The management of failed autologous chondrocyte implantation (ACI) and matrix-assisted autologous chondrocyte implantation (MACI) for the treatment of symptomatic osteochondral defects in the knee represents a major challenge. Patients are young, active and usually unsuitable for prosthetic replacement. This study reports the results in patients who underwent revision cartilage transplantation of their original ACI/MACI graft for clinical or graft-related failure. We assessed 22 patients (12 men and 10 women) with a mean age of 37.4 years (18 to 48) at a mean of 5.4 years (1.3 to 10.9). The mean period between primary and revision grafting was 46.1 months (7 to 89). The mean defect size was 446.6 mm(2) (150 to 875) and they were located on 11 medial and two lateral femoral condyles, eight patellae and one trochlea. The mean modified Cincinnati knee score improved from 40.5 (16 to 77) pre-operatively to 64.9 (8 to 94) at their most recent review (p < 0.001). The visual analogue pain score improved from 6.1 (3 to 9) to 4.7 (0 to 10) (p = 0.042). A total of 14 patients (63%) reported an 'excellent' (n = 6) or 'good' (n = 8) clinical outcome, 5 'fair' and one 'poor' outcome. Two patients underwent patellofemoral joint replacement. This study demonstrates that revision cartilage transplantation after primary ACI and MACI can yield acceptable functional results and continue to preserve the joint.

Maquet III procedure: what remains after initial complications--long-term results.

BACKGROUND: Maquet III procedure, unloved due to its complications (2% to 59%), has been progressively abandoned. At long-term follow-up, what happens to patients with complications that exceeded the initial ones (Acta Orthop Scand 60:20, 1989)? We retrospectively studied patients who were submitted to Maquet III procedure, by functional and radiologic long-term outcomes, in order to determine if this surgery has or has not fulfilled its initially proposed objectives. From 1970 to 1991, 116 patients benefit from the Maquet III procedure. From this, we were able to review in 2011, 23 patients (25 knees) who went through a single Maquet III procedure. Of these patients, 52% were males. Age at surgery was 39.7 ± 11.4, with a postoperative follow-up of 27.2 ± 3.1 years. METHODS: A questionnaire has been prepared for collecting data, and it has been supplemented by clinical records. We evaluated the preoperative complaints, postoperative complications, and range of motion during the recovery time, as well as the postoperative pain-absence period. All patients underwent an objective assessment using the visual analog scale (VAS) at rest and activity, and the Kujala patellofemoral scoring system. A radiological assessment was also made in order to evaluate the arthrosis degree. The bicondylo-patellar angle described by Delgado-Martins (Arch Orthop Traumat Surg 96:303-304, 1980) was used to measure patellar tilt, and the Caton-Deschamps index to calculate the patellar height. RESULTS: Only one knee had benefited from a total knee arthroplasty (20 years after the Maquet III procedure). Preoperative complains were mainly anterior knee pain, crepitus, and patellar instability. Nowadays, 10 patients (40%) still are pain free. Others had an average period without pain of 19.1 ± 6.1 years. VAS at rest was 1.7 ± 0.7 and in activity 4.4 ± 3.0. KPS was 61.9 ± 22.3 points. X-ray shows that 40% had a Kellgren-Lawrence grade of 1 at the patellofemoral joint. CONCLUSION: Maquet proposed this technique for knee-pain relief, maintenance of the knee range of motion, and for slowly progressive osteoarthritic development. Viewed in a dispassionately way, we could notice that the initial objectives of this procedure were completely achieved. A part of 80% of the initial population was lost during follow-up, which may compromise the conclusions, perhaps, it is time to reflect again on this solution, so unloved by so many.

Clinically insignificant association between anterior knee pain and patellofemoral lesions which are found incidentally.

BACKGROUND: Patellofemoral chondral lesions are frequently identified incidentally during the arthroscopic treatment of other knee pathologies. A role has been described for arthroscopic debridement when symptoms are known to originate from pathology of the patellofemoral joint. However, it remains unclear how to manage lesions which are found incidentally whilst tackling other pathologies. The purpose of this study was to establish the strength of association between anterior knee pain and patellofemoral lesions identified incidentally in a typical arthroscopic population. METHODS: A consecutive series of patients undergoing arthroscopy for a range of standard indications formed the basis of this cross section study. We excluded those with patellofemoral conditions in order to identify patellofemoral lesions which were solely incidental. Pre-operative assessments were performed on 64 patients, where anterior knee pain was sought by three methods: an annotated photographic knee pain map (PKPM), patient indication with one finger and by palpated tenderness. A single blinded surgeon, performed standard arthroscopies and recorded patellofemoral lesions. Statistical correlations were performed to identify the association magnitude. RESULTS: Associations were identified between incidental patellofemoral lesions and tenderness palpated on the medial patella (P = 0.007, χ(2) = 0.32) and the quadriceps tendon (P = 0.029, χ(2) = 0.26), but these associations were at best fair, which could be interpreted as clinically insignificant. CONCLUSION: Incidental patellofemoral lesions are not necessarily associated with anterior knee pain, we suggest that they could be left alone. This recommendation is only applicable to patellofemoral lesions which are found incidentally whilst addressing other pathology.

The role of autologous chondrocyte implantation in the treatment of symptomatic chondromalacia patellae.

PURPOSE: Chondromalacia patella is a distinct clinical entity of abnormal softening of the articular cartilage of the patella, which results in chronic retropatellar pain. Its aetiology is still unclear but the process is thought to be a due to trauma to superficial chondrocytes resulting in a proteolytic enzymic breakdown of the matrix. Our aim was to assess the effectiveness of autologous chondrocyte implantation on patients with a proven symptomatic retropatellar lesion who had at least one failed conventional marrow-stimulating therapy. METHODS: We performed chondrocyte implantation on 48 patients: 25 received autologous chondrocyte implantation with a type I/III membrane (ACI-C) method (Geistlich Biomaterials, Wolhusen, Switzerland), and 23 received the Matrix-assisted Chondrocyte Implantation (MACI) technique (Genzyme, Kastrup, Denmark). RESULTS: Over a mean follow-up period of 40.3 months, there was a statistically significant improvement in subjective pain scoring using the visual analogue scale (VAS) and objective functional scores using the Modified Cincinnati Rating System (MCS) in both groups. CONCLUSIONS: Chondromalacia patellae lesions responded well to chondrocyte implantation. Better results occurred with MACI than with ACI-C. Excellent and good results were achieved in 40% of ACI-C patients and 57% of MACI patients, but success of chondrocyte implantation was greater with medial/odd-facet lesions. Given that the MACI procedure is technically easier and less time consuming, we consider it to be useful for treating patients with symptomatic chondral defects secondary to chondromalacia patellae.

Comparison of patellar retention versus resurfacing in LCS mobile-bearing total knee arthroplasty.

PURPOSE: The aim of this retrospective study was to compare clinical outcomes of total knee arthroplasty (TKA) with and without patellar resurfacing using the Low Contact Stress (LCS) mobile-bearing prosthesis in 275 osteoarthritic knees (199 patients) after a minimum of 7 years of follow-up. METHODS: Patients were divided into a patellar retention group (132 knees) and a resurfacing group (143 knees), with median follow-up durations of 7.8 years (range, 7-8.5 years) and 8.5 years (range, 7-10.6 years), respectively. The demographics of the two groups were otherwise matched. The patelloplasty was performed for patellar retention. Patients were evaluated by a blinded, independent observer using Feller's patellar score, the Knee Society score, patient satisfaction, patellar tilt, and lateral displacement. RESULTS: Patellar resurfacing was not superior to retention with respect to any of the measured variables. Eight knees (6.1%) without and 6 (4.2%) with patellar resurfacing had anterior knee pain related to the patellofemoral joint (n.s.). The reoperation rate related to the patellofemoral joint was 0.8% (n = 1) in the retention group compared with 2.8% (n = 4) in the resurfacing group (n.s.). In the 35 patients who underwent bilateral TKA with patellar resurfacing on only one side, there were no significant differences between the two sides in subjective preference, clinical scores, or functional ability. CONCLUSIONS: The clinical and radiographic outcomes of TKA with the LCS mobile-bearing prosthesis showed no significant difference between the two groups after a minimum of 7 years of follow-up. The findings in this study suggest that patellar retention with a patelloplasty may be viable as a routine procedure, even in knees with advanced patellofemoral arthritis, if soft tissue balancing and a patella-friendly prosthetic design are properly used. LEVEL OF EVIDENCE: Therapeutic, retrospective, comparative study, Level III.

Malalignment and cartilage lesions in the patellofemoral joint treated with autologous chondrocyte implantation.

PURPOSE: The aim of our current study is to present the 12.6 years' follow-up results in patients with cartilage lesions of the patellofemoral joint, treated with autologous chondrocyte implantation (ACI) with the use of periosteum. METHODS: Ninety-two patients having patella or trochlea lesion participated in this study. Lysholm and Tegner questionnaires were completed 12.6 years (SD 2.3 years) after the surgery. The patients were asked whether they feel better, worse or had not experienced any difference compared to previous years and whether they would undergo the operation again. Complications or subsequent surgeries were also assessed. RESULTS: Median Tegner score was three, improved by one level compared with preoperative values (P = 0.02). Median Lysholm score was 70, improved by nine points (n.s.). Seventy-two percent of the patients were better or unchanged while 93% would undergo the operation again. Patients with no kissing lesions appeared to have a better prognosis. Patients with malalignment or instability that had undergone a realignment procedure had comparable outcomes to the patients that did not need any additional surgery. Realignment procedures increased the incidence of serious complications but they were associated with decreased incidence of periosteal hypertrophy. No association was found between the age of the patients at the time of the ACI or the size per lesion and any of the clinical outcomes. CONCLUSION: ACI provides a satisfactory outcome for the treatment of cartilage lesions of the patellofemoral joint, even for the cases with concomitant patellar instability. It seems that correcting the coexisting background factors with realignment, stabilizing or unloading procedures, along with the treatment of cartilage lesions, is improving the clinical outcomes over time and decreases the incidence of periosteal hypertrophies although increasing the incidence of serious complications. Our study reveals the good results and the high level of patients' activities (as shown by Tegner score), were preserved 12.6 years after the implantation, in both isolated trochlea and patella lesions and also in multiple and in kissing lesions where an intervention could be considered as a salvage procedure.

Patellofemoral full-thickness chondral defects treated with second-generation autologous chondrocyte implantation: results at 5 years' follow-up.

BACKGROUND: Patellofemoral lesions represent a very troublesome condition to treat for orthopaedic surgeons; however, second-generation autologous chondrocyte implantation (ACI) seems to offer an interesting treatment option with satisfactory results at short-term follow-up. HYPOTHESIS: Hyaluronan-based scaffold seeded with autologous chondrocytes is a viable treatment for the damaged articular surface of the patellofemoral joint. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Among a group of 38 patients treated for full-thickness patellofemoral chondral lesions with second-generation ACI, we investigated 34 who were available for final follow-up at 5 years. These 34 had chondral lesions with a mean size of 4.45 cm(2). Twenty-one lesions were located on the patella, 9 on the trochlea, and 4 patients had multiple lesions: 3 had patellar and trochlear lesions, and 1 had patellar and lateral femoral condyle lesions. Twenty-six lesions (76.47%) were classified as International Cartilage Repair Society (ICRS) grade IV A or B, 5 lesions (14.70%) were grade IIIC, and 3 (8.82%) were lesions secondary to osteochondritis dissecans (OCD). Results were evaluated using the International Knee Documentation Committee (IKDC) 2000 subjective and objective scores, EuroQol (EQ) visual analog scale (VAS), and Tegner scores at 2 and 5 years. Eight patients had second-look arthroscopy and biopsies. RESULTS: All the scores used demonstrated a statistically significant improvement (P < .0005) at 2 and 5 years' follow-up. Objective preoperative data improved from 8 of 34 (23.52%) normal or nearly normal knees to 32 of 34 (94.12%) at 2 years and 31 of 34 (91.17%) at 5 years after transplantation. Mean subjective scores improved from 46.09 points preoperatively to 77.06 points 2 years after implantation and 70.39 at 5 years. The Tegner score improved from 2.56 to 4.94 and 4.68, and the EQ VAS improved from 56.76 to 81.47 and 78.23 at 2 and 5 years' follow-up, respectively. A significant decline of IKDC subjective and Tegner scores was found in patients with multiple and patellar lesions from 2 to 5 years' follow-up. Second-look arthroscopies in 8 cases revealed the repaired surface to be nearly normal with biopsy samples characterized as hyaline-like in appearance. CONCLUSION: Hyaluronan-based scaffold seeded with autologous chondrocytes can be a viable treatment for patellofemoral chondral lesions.

[Analgesic effect of intra-artcular fentanyl in knee arthroscopy to treat patellofemoral lateral hyperpressure syndrome]. / Efecto analgésico del fentanyl intraarticular en artroscopía de rodilla para el síndrome de hiperpresión lateral patelofemoral.

INTRODUCTION: During arthroscopy for the treatment of patellofemoral lateral hyper-pressure syndrome (LHS), intra-articular morphine or its derivatives (fentanyl) may reduce postoperative pain when combined with anesthetics. We therefore decided to determine whether adding fentanyl to epinephrine and bupivacaine produced an increased analgesia. MATERIAL AND METHODS: We randomly distributed 40 patients into two groups. The experimental group (n=20) was given 0.5% bupivacaine (2 mg/kg), epinephrine (100 microg) and fentanyl (2.5 microg/kg). The control group (n=20) received 0.5% bupivacaine (2 mg/kg) and epinephrine (100 microg). Patients underwent chondroplasty and retinacular release, and we assessed pain, time of analgesia and postoperative range of motion at postoperative hours 6 and 24. RESULTS: The age and the grade of patellofemoral chondromalacia (PFC) were similar in both groups (p > 0.05). No differences were found in pain and ranges of motion intraoperatively and at postoperative hours 6 and 24 (p > 0.05) between both groups. The postoperative analgesia time was similar (p > 0.05). CONCLUSIONS: Adding intra-articular fentanyl to the combination of epinephrine plus bupivacaine did not decrease pain, and did not increase neither the analgesia time nor the range of motion in patients with LHS undergoing knee arthroscopy.

[Lateral retinacular release]. / Die laterale Retinaculumspaltung.

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.

Ex vivo comparison of mechanical versus thermal chondroplasty: assessment of tissue effect at the surgical endpoint.

PURPOSE: The purpose of this study was to evaluate tissue effect (tissue removal plus underlying cell death) of two chondroplasty techniques: mechanical debridement (MD) using a rotary shaver blade and thermal chondroplasty using radiofrequency energy (RFE). METHODS: Forty-eight human chondromalacic cartilage samples were treated with either MD or RFE. Pre- and post-treatment arthroscopic images of the cartilage surface were recorded. Samples were incubated with cell viability stain and visualized with confocal laser microscopy to determine tissue effect. Smoothing was quantitated by three surgeons using a visual analog scale (VAS) as well as a subjective rating regarding whether smoothing was "arthroscopically acceptable." RESULTS: Tissue effect at the surgical endpoint of arthroscopically acceptable smoothing was 385 microm for MD versus 236 microm for RFE, a significant difference (P < .0001). Mean post-treatment VAS for MD was 2.8 points less smooth than for RFE (P < .0001). Overall, arthroscopically acceptable smoothing was achieved in 90% of RFE samples compared to 49% of MD samples. CONCLUSIONS: Our results shown that chondroplasty using a RFE probe results in greater smoothing of chondromalacic cartilage in fewer treatment passes and with decreased total tissue effect than MD using a rotary shaver blade. CLINICAL RELEVANCE: If safety and efficacy can be shown in vivo, thermal chondroplasty may represent an alternative for treatment of symptomatic chondromalacia.

Comparison of radiofrequency treatment and mechanical debridement of fibrillated cartilage in an equine model.

OBJECTIVE: To compare a radiofrequency energy (RFE) prototype probe to mechanical debridement (MD) and a commercially available RFE system used for chondroplasty in the treatment of an experimentally created partial thickness cartilage lesion in horses. The study design was experimental, randomized complete block, n=8, using fifteen mature ponies. METHODS: Grade 2 to 3 cartilage lesions were prepared in both patellae. After 10 months duration, the injuries were used to study the effects of MD, a commercially available bipolar RFE device (CoVac 50; ArthroCare Corporation) and a prototype monopolar RFE device (Smith & Nephew Endoscopy). Six months after treatment the patellae were examined for chondrocyte viability and cartilage structure. RESULTS: Mean depth of cell death was significantly different among groups (controls, MD

Arthroscopic debridement for grade III and IV chondromalacia of the knee in patients older than 60 years.

Arthroscopic debridement has been used to treat patients with degenerative knee osteoarthritis, although there is sometimes conflicting evidence documenting its efficacy. This study evaluates the success of arthroscopic debridement in elderly patients with grade III and IV chondromalacia of the knee as measured by patient satisfaction and the need for additional surgery. From December 1998 to August 2001, a total of 102 consecutive cases of knee arthroscopy in 99 patients > 60 years were performed. Average follow-up was 34 months (range: 7-104 months). Patients were asked about their satisfaction using a visual analog scale, and the presence of meniscal lesions during arthroscopy and the treatment for these lesions were evaluated. Knees also were assessed for articular surface degeneration using Outerbridge's classification for chondromalacia. The need for and type of additional surgery was evaluated. During arthroscopy, meniscal lesions requiring a partial meniscectomy were found in 95 knees. Chondromalacia was found in 92 knees; 53 knees had grade I or II chondromalacia and 39 knees had grade III or IV chondromalacia. Additional surgery was performed in 17 knees. Mean patient satisfaction score was 73 (range: 50-100) in the 39 knees with grade III or IV chondromalacia after arthroscopic debridement was performed. These findings suggest arthroscopic debridement in elderly patients has a place in the treatment algorithm for grade III or IV chondromalacia of the knee.

Combined proximal and distal realignment procedures to treat the habitual dislocation of the patella in adults.

BACKGROUND: Habitual dislocation of the patella (HDP) is a rare condition. Many surgical procedures using proximal realignment have been reported to treat HDP in children, with around 80% satisfactory results. However, few articles have addressed the treatment of HDP associated with high-grade patellofemoral chondromalacia in adults. HYPOTHESIS: A combination of proximal and distal realignment procedures of the patella will reduce pain and increase function in adult patients with HDP. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Twelve patients with 13 symptomatic cases of HDP of the knee underwent surgical treatment that included lateral release, medial retinaculum advancement, and the anteromedial tibial tubercle transfer procedure. The average period between dislocation and surgery was 10.8 years. One patient had an additional procedure, an open-wedge varus corrective osteotomy of the distal femur, because of a 20 degrees valgus deformity of the knee. The patellofemoral morphology study included routine and Merchant views of the knee and a computed tomography scan at full extension and at 30 degrees flexion of the knee, before the operation and at follow-up. Any associated intra-articular pathologic findings during the surgical procedure were addressed. Patellofemoral function was evaluated with the Kujala functional score before surgery and at the time of the final follow-up. RESULTS: Chondromalacia of the patella over the medial facet and central ridge was grade III in 8 knees and grade IV in 5 knees. Corresponding chondral erosion of the lateral femoral condyle was noted in every knee. All patients were followed for an average period of 67.3 months (range, 25-103 months). The average preoperative Kujala functional score was 43.9 and the average postoperative score was 88.9 (P< .05). Radiographically, there was a statistically significant improvement in the congruence angle from 62.1 degrees +/- 15.0 degrees preoperatively to -2.7 degrees +/- 9.8 degrees postoperatively (P< .01) and in the lateral patellofemoral angle from -40.2 degrees +/- 9.3 degrees preoperatively to 1.4 degrees +/- 7.0 degrees postoperatively (P< .01). No patient has reported an episode of patellar dislocation after the surgical procedures. CONCLUSION: Combined proximal and distal realignments of the patella effectively treat HDP in adults with associated high-grade patellofemoral chondromalacia.

Determination of factors influencing tissue effect of thermal chondroplasty: an ex vivo investigation.

PURPOSE: Scientific investigation of thermal chondroplasty using radiofrequency energy (RFE) is confounded by multiple factors associated with the technique. Our purpose was to determine the relative importance of the following factors on tissue effect (depth of tissue debridement plus depth of underlying cell death) of thermal chondroplasty: probe design, generator power setting, speed, force, and number of passes of the probe over treated tissue. We hypothesized the relative importance of these factors would be (from most to least important) power, passes, speed, force, and design. METHODS: Bovine patellae were treated using monopolar RFE. Sample size was based on a 2-level, half-factorial design. Low and high extremes of the factors tested were power setting (50 W v 110 W), passes (1 v 5), speed (3 mm/sec v 10 mm/sec), force (0.15 N v and 0.59 N), and probe design (electrode protrusion 25 microm v 125 microm). Samples were incubated with cell viability stain and examined using confocal laser microscopy to determine tissue effect. Data were analyzed using multiple regression. RESULTS: All factors that were tested significantly influenced tissue effect (P < .05). Power setting had the greatest effect, followed by design, speed, passes, and force. The following interactions of factors were also significant: design and force, power and passes. The optimal configuration resulting in least tissue effect was a power setting of 50 W, electrode protrusion of 25 microm, speed of 10 mm/sec, 1 pass, and 0.15 N of applied force during treatment, which resulted in a predicted tissue effect of 99 +/- 15 microm. CONCLUSIONS: The least tissue effect of thermal chondroplasty was achieved with lower power using a probe with minimal electrode protrusion while performing a rapid, single, lower force pass of the probe over treated tissue. CLINICAL RELEVANCE: Power and probe design have the greatest influence among the factors tested; selecting these parameters preoperatively could control tissue effect.

Who is the ideal candidate for autologous chondrocyte implantation?

We investigated the prognostic indicators for collagen-covered autologous chondrocyte implantation (ACI-C) performed for symptomatic osteochondral defects of the knee. We analysed prospectively 199 patients for up to four years after surgery using the modified Cincinnati score. Arthroscopic assessment and biopsy of the neocartilage was also performed whenever possible. The favourable factors for ACI-C include younger patients with higher pre-operative modified Cincinnati scores, a less than two-year history of symptoms, a single defect, a defect on the trochlea or lateral femoral condyle and patients with fewer than two previous procedures on the index knee. Revision ACI-C in patients with previous ACI and mosaicplasties which had failed produced significantly inferior clinical results. Gender (p = 0.20) and the size of the defect (p = 0.97) did not significantly influence the outcome.