Revision of inlay resurfacing prosthesis with patellar realignment surgery and a new inlay prosthesis for persistent patellofemoral pain und patella subluxation.

We present the case of a 35-year-old patient who underwent inlay patellofemoral arthroplasty (I-PFA) followed by secondary patellar realignment surgery and inlay-to-inlay revision. Revision was performed because of ongoing pain, crepitation, and lateral subluxation of the patella. The original patella component (30-mm button) was replaced with a 35-mm dome, while the Hemi-Cap Wave® (7 × 5 mm) I-PFA was replaced with the Hemi-Cap Kahuna® (10 × 5 mm). At the 1-year follow-up, the clinical symptoms were resolved. Radiography revealed an aligned patellofemoral compartment with no signs of loosening. Inlay-to-inlay PFA revision appears to be a reasonable alternative to total knee arthroplasty and conversion to onlay-PFA (O-PFA) for symptomatic patients with primary I-PFA failure. Thorough patellofemoral evaluation and appropriate patient and implant selection are key for successful I-PFA, while additional procedures for patellar realignment may also be required for satisfactory long-term outcomes.

Autologous chondrocyte implantation combined with anterior cruciate ligament reconstruction: similar short-term results in comparison with isolated cartilage repair in ligament intact joints.

PURPOSE: Both acute ruptures of the anterior cruciate ligament (ACL) as well as chronic ACL insufficiency show a high association with focal cartilage defects of the knee. However, the results after combined ACL reconstruction and cartilage repair are not well investigated. The aim of the present study was to investigate the short-term outcomes after autologous chondrocyte implantation (ACI) in combination with ACL reconstruction and to compare the results with patients who underwent isolated ACI in ligament intact knees. METHODS: All patients who were registered in the German Cartilage Registry with ACI for focal cartilage defects in the knee joint in combination with ACL reconstruction and who completed the 24 month follow-up were included in the study group. A matched-pair procedure according to gender, defect location, defect size, and age was used to create a control group of patients with isolated ACI in ACL intact joints. The Knee Injury and Osteoarthritis Outcome Score (KOOS) and the numeric analog scale for pain (NAS) were used to assess the preoperative state as well as the clinical outcomes 12 and 24 months after surgery. RESULTS: A total of 34 patients were included in both the study group (age mean 33.3 ± SD 8.8 years) and the control group (33.6 ± 8.4 years) with a median defect size of 466 (25%-75% IQR 375-600) mm2 and 425 (IQR 375-600) mm2, respectively. In comparison with the preoperative state (median 67, IQR 52-75), the study group showed a significant increase of the total KOOS after 12 months (78, IQR 70-86; p = 0.014) and after 24 months (81, IQR 70-84; p = 0.001). The NAS for pain did not change significantly in the postoperative course. In comparison with the control group there was no significant difference for the total KOOS neither preoperative (control group median 67, IQR 52-73) nor at any postoperative time point (12 months: 82, IQR 67-93; 24 months: 81, IQR 71-91). CONCLUSION: The clinical short-term outcomes after ACI at the knee joint in combination with ACL reconstruction are good and similar to the results after isolated ACI in ligament intact knees. LEVEL OF EVIDENCE: III.

Effect of Previous Knee Surgery on Clinical Outcome After ACI for Knee Cartilage Defects: A Propensity Score-Matched Study Based on the German Cartilage Registry (KnorpelRegister DGOU).

BACKGROUND: Autologous chondrocyte implantation (ACI) is an established procedure for the treatment of cartilage damage in the knee joint. At present, it is still unclear how previous surgery influences outcome after ACI. PURPOSE: To evaluate the effect of previous knee surgery related or nonrelated to the treated cartilage defect on clinical outcome after ACI for knee cartilage defects. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: An overall 730 patients with ACI who underwent previous unspecific knee surgery, whether related to the defect being currently treated or not, were identified from a cohort of 5961 patients registered in the German Cartilage Registry. Propensity score matching was used to match these patients to 690 patients with analogous characteristics but without previous surgery. Subsequently, 317 patients with previously failed cartilage treatment at the defect site were identified and compared with a matched collective of 254 patients without previous cartilage treatment. In a subgroup analysis, the type of previous cartilage surgery was additionally investigated. Outcome was evaluated by Knee injury and Osteoarthritis Outcome Score (KOOS), visual analog scale for pain, rate of reintervention, and patient satisfaction up to 36 months. A chi-square test was used to compare categorial variables and an unpaired t test to compare continuous variables. RESULTS: Patients with previous knee surgery not related to the cartilage defect showed a lower KOOS at 6 months (68.3 vs 70.8; P = .026), while patients with previous cartilage surgery showed significantly lower KOOS values at all follow-up time points when compared with patients without any previous knee or cartilage surgery (all P < .05). A comparison of KOOS values in patients with previous therapy at the cartilage defect with ACI versus bone marrow stimulation did not show any significant differences at any follow-up. CONCLUSION: Previously failed cartilage treatment at the defect site represents a negative prognostic factor up to 3 years after ACI. However, this influence appears to be independent of the type of previous treatment at the defect site and applies equally to failed bone marrow stimulation as well as previous ACI. In contrast, a negative effect of previous surgery to the knee unrelated to the cartilage defect could not be shown in the 3-year follow-up.