Aim

Nail patella syndrome (NPS) is a skeletal dysplasia with patellofemoral dysfunction as a key symptom. We present the first in-depth radiological evaluation of the knee in a large series of NPS patients and describe the typical malformations.

A Prosthetic Joint infection (PJI) is an orthopedic disaster. There is a direct correlation between persistent wound drainage (>72 hours) and the development of a PJI. It is unknown if early wound drainage (<12 hours) is correlated with PJI.

We included 753 consecutive patients treated with a Total Hip Arthroplasty (THA) or Total Knee Arthroplasty (TKA) operated between December 2012 and December 2013. All patients were treated according to our local fast track joint surgery protocol. We retrospectively analyzed the prospectively collected data on wound drainage and PJI.

The diagnosis PJI was established according to the definition by the International Consensus Group on Prosthetic Joint Infections. Per PJI-case, two control-cases were matched on type of surgery (THA or TKA) and day of surgery. Analysed variables were co-morbidities, medication, use of drains, haematoma, wound drainage and dressing changes. Statistical analysis was done using Kaplan Meier logistic regression with statistic significance set at p<0.005.

In 753 included patients, 25 PJI-cases were identified and 50 controls were matched. Cases had significant more wound drainage (88% vs 36% P=0.001)) and wound dressing changes (56% vs 18% P=0.006) in the direct postoperative phase (<12 uur postoperative). Cases had more haematoma (44% vs 10% P=0.005). We found no association between PJI and co-morbidity, medication and use of drains.

We found that wound drainage directly postoperative (<12hr) correlated with PJI. We believe that direct post operative drainage is of crucial importance in the development of PJI and inhibition of drainage offers opportunities for prevention of PJI. The use of tranexamic acid, suction drains and critical evaluation of guidelines for preventing thrombo embolic events all offer reducing the risk on wound drainage and the development of PJI.

An increased tibial tubercle–trochlear groove (TT-TG) distance is related to patellar maltracking and instability. Tibial tubercle transfer is a common treatment option for these patients with good short-term results, although the results can deteriorate over time owing to the progression of osteoarthritis. We present a ten-year follow-up study of a self-centring tibial tubercle osteotomy in 60 knees, 30 with maltracking and 30 with patellar instability. Inclusion criteria were a TT-TG ≥ 15 mm and symptoms for > one year. One patient (one knee) was lost to follow-up and one required total knee arthroplasty because of progressive osteoarthritis. Further patellar dislocations occurred in three knees, all in the instability group, one of which required further surgery. The mean visual analogue scores for pain, and Lysholm and Kujala scores improved significantly and were maintained at the final follow-up (repeated measures, p = 0.000, intergroup differences p = 0.449). Signs of maltracking were found in only a minority of patients, with no difference between groups (p > 0.05). An increase in patellofemoral osteoarthritis was seen in 16 knees (31%) with a maximum of grade 2 on the Kellgren–Lawrence scale. The mean increase in grades was 0.31 (0 to 2) and 0.41 (0 to 2) in the maltracking and instability groups respectively (p = 0.2285)

This self-centring tibial tubercle osteotomy provides good results at ten years’ follow-up without inducing progressive osteoarthritis.

Cite this article: Bone Joint J 2015;97-B:329–36.

Lateralisation of the tuberosity tibia causes distal malalignment of the extensor mechanism of the knee and can lead to lateral tracking patella (LTP), resulting in anterior knee pain, or objective patellar instability (OPI), resulting in recurrent luxations. For a precise preoperative diagnosis the tuberositas tibia (TT) trochlear groove (TG) distance was measured on a CT scan. A distance of more than 15 mm was considered to be pathological.

In a prospective study, the clinical results of a subtle, CT-guided medial tuberosity transfer for LTP and OPI were evaluated. 30 Consecutive patients with LTP and 30 patients with OPI and an increased TT TG were included. Outcomes were documented at 3, 12 and 24 months follow-up using the Lysholm scale, the Kujala score, and a visual analogue pain score. Postoperatively all but one patient reported good improvement in stability (no persistent subluxations or luxations). All patients had a marked improvement in pain and functional scores at follow up. Complications seem to be related to the peroperative technique. CT-guided TT transfer appears to be satisfactory and safe method for treating patients with an increased TT TG leading to either LTP or OPI.

An abnormal lateral position of the tibial tuberosity causes distal malalignment of the extensor mechanism of the knee and can lead to lateral tracking of the patella causing anterior knee pain or objective patellar instability, characterised by recurrent dislocation. Computer tomography is used for a precise pre-operative assessment of the tibial tubercle-trochlear groove distance. A distance of more than 15 mm is considered to be pathological and an indication for surgery in symptomatic patients.

In a prospective study we performed a subtle transfer of the tibial tuberosity according to the information gained from the pre-operative CT scan. This method was applied to two groups of patients, those with painful lateral tracking of the patella, and those with objective patellar instability. We evaluated the clinical results in 30 patients in each group. The outcome was documented at 3, 12 and 24 months using the Lysholm scale, the Kujala score, and a visual analogue pain score.

Post-operatively, all but one patient in the instability group who had a patellar dislocation requiring further surgery reported good improvement with no further subluxation or dislocation. All patients in both groups had a marked improvement in pain and functional score. Two patients sustained a tibial fracture six and seven weeks after surgery. One patient suffered a per-operative fracture of the tibial tubercle which later required further fixation.

If carefully performed, this type of transfer of the tibial tubercle appears to be a satisfactory technique for the treatment of patients with an increased tibial tubercle-trochlear groove distance and who present with symptoms related to lateral maltracking of the patella.