Aims: Anterior knee pain is a common complaint of mixed aetiology, and in many cases no demonstrable cause is identified. For patients with persistant anterior knee pain, tibial tubercle transfer (TTT) can be a surgical option. The aim of this study is to assess the effectiveness of TTT for chronic anterior knee pain resistant to conservative treatment. Method: All patients with arthroscopically proven Chondromalacia patellae (CMP) without clinical evidence of patella instability, who have failed to respond to conservative treatment such as physiotherapy were included in the trial. They underwent TTT with a modified Fulkerson technique and then routine post-operative care with a cricket pad splint for 2–4 weeks. Pre and post-operative scores were obtained using a Kujala patello-femoral score, a visual analogue score for pain and a patient satisfaction score. The Outerbridge grading was used to score the severity of CMP at arthroscopy. Results: There were 50 TTT’s followed up (7 staged bilaterals) with a mean follow up of 32.4 months (5–88 months). There were significant improvement in the pre-operative and post-operative Kujala (p> 0.001) and visual analogue pain scores (p> 0.001). Of the 50 TTT’s 70% had an excellent or good result and 30% a fair or poor result. Moreover 76% claimed that they would have the same operation again for their condition. There was no significant correlation between Outerbridge grading and post-operative outcome. Complications include late anterior knee pain (10 cases), superficial wound infection (1 case), non-union of osteotomy (1 case) and tuberosity fracture (1 case). Conclusion: Anteromedial tibial tubercle transfer is a reliable and effective treatment for peristant anterior knee pain

Purpose: Since the pathomechanism of patellofemoral malalignment is complex, multifactorial and varies individually, the ideal treatment has been a matter of controversy. The purpose of this study was to demonstrate the clinical outcome and radiographic changes of knees with patellofemoral malalignment treated with Fulkerson osteotomy after a minimum follow-up of 24 months. Materials and Methods: Sixty knees in 40 patients (32 female and 8 male) were examined with a mean of 55 20 (25 97) months after having undergone medialization of the tibial tubercle using Fulkerson osteotomy for patel-lofemoral malalignment. Mean age at surgery was 20 7 (12 42) years. Prior surgery of medial retinacular plication in 4 knees and lateral retinacular release in 1 knee had been performed. During surgery, amount of tibial tubercle transfer was determined by examining the patellar tracking over full range of knee motion. After Fulkerson osteotomy, proximal realignment procedures were added depending on arthroscopic appearance of the patellofemoral adaptation. The clinical outcome was evaluated using Fulkersons knee instability scale. The radiographic parameters including congruence angle, lateral patellofemoral angle, tilting angle and lateral shift ratio were measured in Merchant view. Results: Mean distance of medial transfer of tibial tubercle was 12.8 3.1 (8 22) mm. Lateral retinacular release in 54 knees and adductor magnus tenodesis (Avikainen procedure) in 2 knees were simultaneously performed combined with Fulkerson osteotomy. All radiographic parameters at the final follow-up were significantly improved compared to the preoperative values (p < 0.05 in a paired t-test), that is, from 23.0 14.6 to 0.4 13.7 degrees in congruence angle, from −6.3 9.0 to 0.4 6.9 degrees in lateral patellofemoral angle, from 25.1 11.5 to 16.3 5.6 degrees in tilting angle and from 35 24 to 17 9% in lateral shift ratio. Mean score in Fulkersons knee instability scale was 96 5 points at the final follow-up. All knees except 3 were ranked as excellent, very good or good. Two knees with moderate osteoarthritis of the patellofemoral joint were ranked as fair. One knee that had postoperative recurrence of patellar subluxation underwent a revision surgery with Avikainen procedure. Discussion: In the clinical study with a minimum 2-year follow-up, Fulkerson tibial tubercle osteotomy provided excellent or good overall outcome in 93% of patients in combination with proximal realignment surgeries. Although all radiographic parameters were significantly improved, it was found that the lateral shift of the patella was more effectively corrected compared to the lateral tilt. It was suggested that reconstruction of the medial patellofemoral structures might be more suitable than Fulkerson osteotomy for some knees characterized by significant lateral tilt

We present 10–15 year follow-up of 33 patients who underwent Elmslie-Trillat osteotomy for severe patellar subluxation or dislocation. In the literature it has been reported that tibial tubercle osteotomy predisposes to subsequent patella-femoral arthritis, however it has never been documented if pre existent knee chondral damage has any role in this development. In our group all patients had pre-op knee arthroscopy performed and extant of chondral damage was documented. We pre-formed an evaluation by long-term follow-up to determined weather pre-op chondral damage was the cause of subsequent osteoarthritis of patella-femoral joint. All patients were invited to attend outpatient clinic for clinical examination and knee radiographs and assessed by an independent research surgeon. Mean age at follow-up was 43 years and average follow-up was 10.5 years (range 10–15 years). 90% follow-up was achieved. Knee function was assessed by clinical scores (Lysholm knee score, American Knee Score, Oxford Knee score, Tegner and Insall knee scores) and three radiographs (AP, Lateral and Merchant views) were performed. Four patients had developed significant arthritis and underwent joint arthroplasty. Majority of patients reported good results with no further dislocation. However we noticed that extant of pre-op chondral damage was a significant factor in subsequent development of patella-femoral arthritis. We will present our data which is unique as no previous such long-term results have been reported for tibial tubercle transfers followed-up for more than 10 years and have pre-op arthroscopic documented chondral damage

We present 10–15 year follow-up of 33 patients who underwent Elmslie-Trillat osteotomy for severe patellar subluxation or dislocation. In the literature it has been reported that tibial tubercle osteotomy predisposes to subsequent patella-femoral arthritis, however it has never been documented if pre-existent knee chondral damage has any role in this development. In our group all patients had pre-op knee arthroscopy performed and extant of chondral damage was documented. We preformed an evaluation by long-term follow-up to determine weather pre-op chondral damage was the cause of subsequent osteoarthritis of patella-femoral joint. All patients were invited to attend outpatient clinic for clinical examination and knee radiographs and assessed by an independent research surgeon. Mean age at follow-up was 43 years and average follow-up was 10.5 years (range 10–15 years). 90% follow-up was achieved. Knee function was assessed by clinical scores (Lysholm knee score, American Knee Score, Oxford Knee score, Tegner and Insall knee scores) and three radiographs (AP, Lateral and Merchant views). Four patients had developed significant arthritis and underwent joint arthroplasty. Majority of patients reported good results with no further dislocation. However we noticed that extant of pre-op chondral damage was a significant factor in subsequent development of patella-femoral arthritis. We will present our data which is unique as no previous such long-term results have been reported for tibial tubercle transfers followed-up for more than 10 years and have pre-op arthroscopic documented chondral damage

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.

Patients with recurrent patella instability, who have an abnormal patellofemoral alignment (patella height or tibial tubercle-trochlear groove (TTTG) distance), benefit from tibial tubercle transfer along with medial patellofemoral ligament (MPFL) reconstruction. Between July 2008 and April 2013, 18 patients (21 knees) with recurrent patellar instability underwent combined MPFL reconstruction and tibial tubercle transfer. All patients had abnormal patellofemoral alignment in addition to MPFL insufficiency. 15 patients (16 knees) with a mean age of 24 years (16–41) had a mean follow up of 26 months (6–55). We assessed the outcome using KOOS, KUJALA, activity level and patient satisfaction scores. All patients had a stable patella. There was a significant improvement in outcome scores in 12 out of 15 patients. At final follow up KOOS score had improved from 68.25(44 to 93.9) to 77.05(48.8 to 96.4) and KUJALA score had improved from 63.3(41–88) to 78.06 (45 to 99). 9 patients showed excellent results and achieved at least a pre-injury level of activity. 4 of these had activity level better then preoperative level. 6 patients had a lower activity level than pre-injury (1 – ongoing physiotherapy, 1 – because of lack of confidence, and 4 – Life style modification). 14 patients were satisfied and happy to recommend this procedure. There were 3 postop complications, with 2 cases of stiffness and 1 case of non-union of the tibial tuberosity. Our prospective study has shown that restoration of tibial tubercle-trochlear groove index, Patella height and Medial Patellofemoral Ligament reconstruction yields good results in carefully selected patients

70 patients who underwent dynamic MRI scanning for chronic anterior knee pain were retrospectively evaluated. All patients had been symptomatic for over a year. 43 patients had been treated conservatively and 27 had undergone surgical procedures (arthroscopy -13, lateral release- 9, tibial tubercle transfer 5). The extent of subluxation, tilt and cartilage abnormalities on MRI scans, during resisted extension were assessed. Functional scoring (Oxford, Lysholm and Tegner scores) was done through questionnaires and correlated with the radiological findings. 54 (77%) patients were found to have some patellofemoral abnormality on the scans. Subluxation was the most common finding with mild subluxation in 30, moderate in 18 and severe in 17 knees. Mild tilt was seen in 26 knees and moderate to severe tilt in 14 knees. Tilt was found in association with subluxation except in 8 cases. Grade 1 and 2 cartilage wear were seen in 13 knees and Grade 3 and 4 in 21 knees. The “Tibial Tubercle to Trochlear Groove distance” (TTD) was measured in all knees and correlated with subluxation. The average distance was 13.5mm, 13.6mm and 18.8mm for mild, moderate and severe subluxation respectively. All patients with a TTD _ 20mm had moderate or severe subluxation. The specificity of a TTD _ 20mm for severe maltracking was 100% but the sensitivity was only 42%. The TTD appears to be the single most significant parameter determining patella tracking. We have proposed an algorithm for the surgical and non-surgical treatment of chronic anterior knee pain. We recommend lateral release for those with moderate and severe subluxation and a tibial tubercle transfer as well in those with a TTD _ 20mm. The functional scores did not zshow a significant correlation with the grading of subluxation

To stabilise the dislocating patella, one can increase the medial vectors, decrease the lateral vectors, or combine these options. Oblique strengthening of vastus medialis increases the medial vectors. This muscle is an active secondary constraint for stabilising the patella. Strengthening this muscle is the cornerstone of treatment of patellar instability, but it is often unsuccessful if the medial patello-femoral ligament is deficient. The medial patellofemoral ligament is the primary passive constraint to lateral dislocation of the patella. Reconstruction of this ligament, which tenses in extension, stabilises the patella in most cases, without the danger of secondary late-stage patellofemoral degeneration. However, in high-riding patellae, effective ligament reconstruction may cause an extensor lag. An elevation of more than 3 mm affects the contact pressures by disturbing the unique relationship between patella and trochlea. Because it can lead to late stage patellofemoral degeneration, trochleaplasty is rarely indicated. Tibial tubercle transfer decreases the lateral vectors and is indicated in cases of severe patella alta, a markedly increased Q-angle and lateral patellar tilt. The tubercle can be transferred distally or medially or internally rotated. The procedure changes the patellofemoral relationship, increasing the load in the medial tibio-femoral compartment and giving rise to the possibility of late-stage degeneration in both the patellofemoral and the tibiofemoral joints. It should not be undertaken lightly and the amount of shift should be conservative. The lateral retinaculum, which becomes lax in extension in right in flexion, provides about 10% of patellar stability to lateral dislocation. Because most patellae dislocate in early flexion, lateral retinacular release is seldom indicated except in the rare cases where the patella dislocates in late flexion. In severe cases of patellar instability, it might be necessary to combine reconstruction of the medial patello-femoral ligament with tibial tubercle transfer and even with lateral retinacular release

The aim of this study was to assess the outcome of patients who underwent ElmslieTrillat antero-medial tibial tubercle transfer for treatment of persistent symptomatic anterior knee pain due to chondromalacia patellae. We performed a prospective analysis of 23 patients who underwent Elmslie-Trillat antero-medial tibial tubercle transfers over a five year period for chronic anterior knee pain and an arthroscopic diagnosis of chondromalacia patellae. All patients who presented with anterior knee pain underwent an initial period of physiotherapy and all patients whose symptoms persisted following physiotherapy underwent arthroscopic assessment. Patients who continued to experience debilitating symptoms despite this initial treatment and who also had a diagnosis of chondromalacia patellae from arthroscopic assessment were listed for an Elmslie-Trillat tibial tubercle anteromedialisation. Patients who gave a history of instability or dislocation were excluded. The average age of patients undergoing surgery was 34 years (21–48 years) and the average time between arthroscopic diagnosis and surgery was 14 months. All patients who underwent surgery had pre and post operative KuJala patellofemoral scoring. The average pre-operative score was 54 (30–78) and post operative score 76 (46–100). The average post operative assessment was 25 months (6–62 months). Twenty one patients had improved post operative scores with one having a worse score and one score remaining unchanged following surgery. Nineteen patients felt that their symptoms had improved, three felt that there had been no change and one felt that they were worse after surgery. When asked if the improvement in symptoms had been worthwhile nineteen stated that they would undergo surgery again if in the same situation and four stated that they would not. The treatment of symptomatic chondromalacia patellae remains a challenge. Although a more selective approach to individuals with anterior knee pain is widely advocated in the literature this study demonstrates that good results can still be achieved in patients treated empirically with a tibial tubercle anteromedialisation

A simple procedure of using a Smillie knife to release the lateral patellar retinaculum and the capsule in the unstable patella syndrome is described. The syndrome includes recurrent dislocation, recurrent subluxation and acute dislocation of the patella. Arthroscopy, to exclude any other pathology such as chondromalacia patellae, is performed before proceeding to closed lateral release. The results of this procedure are as good as those after more major surgical procedures. In a small percentage of patients a second operation such as tibial tubercle transfer or patellectomy may be necessary, especially in patients with an underlying congenital abnormality; but in many patients this type of major surgery has proved unnecessary

Purpose of Study:. Various techniques have been described and are still used for treating recurrent dislocation of the patella when conservative measures fail. Among them are distal, proximal and combined realignment techniques and lateral releases. Since being shown proof of the biomechanical importance of the medial patellofemoral ligament (MPFL) in patellofemoral instability, the reconstruction of the MPFL has gained in popularity. The objective of this paper is to present a case series with preliminary clinical results using the gracilis tendon to reconstruct the MPFL. Method:. Between 01/07 and 03/11 23 knees in 21 patients underwent reconstruction of the MPFL.4 of these patients had had previous surgery. Preoperatively the Caton Deschamps ratio using plain x-rays was worked out and the TT/TG distance was measured using CT scanning. Using these measurements as a guideline, 7 cases underwent a tibial tubercle transfer as an additional procedure. In 6 of the cases an additional cartilage procedure was required. The technique was simplified using intra-operative x-rays to achieve anatomical tunnel placement. Results:. The Tegner Activity Score was used to evaluate the patients preoperatively and at a minimum of 6 months postoperatively. The scores improved on average from 3,6 to 7,4. One patient had an extensor lag of 10 degrees at 3 months. This had normalised by 6 months. One patient had recurrence of her instability and required a revision MPFL reconstruction using an allograft. One patient had recurrent episodes of patella subluxation but no overt dislocation. Conclusion:. This case series gave good functional results using the Tegner Activity score. The procedure of MPFL reconstruction was effective in stabilising the patellae and in improving the symptoms of patellofemoral instability

We report a case of a 20-year-old microcephalic patient who suffered from symptomatic patellar dislocation since his early days. His patella was laterally dislocated from full extension to 40° of flexion and would remain subluxated thereafter. His CT-scan revealed excessive ipsilateral femoral neck anteversion (45°) that resulted in substantial internal femoral torsion and subsequently led to patella dislocation. He was treated in one stage with a stepwise procedure, that involved arthroscopic assessment of patellar tracking followed by derotational femoral shaft osteotomy. Tracking was reassessed arthroscopically and although improved was still suboptimal. Therefore an arthroscopic lateral release and an Elmslie-Trillat tibial tubercle transfer were undertaken. This led to very satisfactory patellar tracking. One year postoperatively he had significant functional improvement, no further episodes of patellar dislocation and a ROM of 0–110°. His Lysholm score improved from 45 to 88, his Tegner activity scale from 2 to 4 and his Knee Outcome Score from 38/80 to 70/80. This complex case highlights excessive femoral neck anteversion as a causative factor for patella dislocation. A combination of proximal and distal bony realignment procedures is proposed and the role of arthroscopy is emphasised

Purpose of the study: To develop a new treatment algorithm for patients with chronic anterior knee pain based on kinematic patella tracking MR imaging. Methods and Results: Patients with anterior knee pain of more than one year duration and not responding to non-operative treatment, underwent kinematic MRI study. The provocative test was performed with the conventional MRI scanner and the patient extending the knee against resistance, the resistance provided by inflated beach ball. A retrospective analysis was done of first seventy patients, who had undergone this scanning technique. On the imaging films, four measurements were made. They were patella subluxation, tilt, cartilage thickness and the Tibial Tubercle Trochlear distance (TTD). Patellar subluxation was classified as mild, moderate and severe. We found that a Tibial Tubercle Trochlea distance of 18mm had a specifity of 100% and a sensitivity of 89% for severe maltracking. Conclusion: Kinematic MR Imaging is a useful investigation before considering operative treatment for patients with chronic anterior knee pain. Based on our study, we conclude that those patients with moderate lateral maltracking with a TTD< 18 mm should be offered lateral release and those with severe maltracking and TTD> 18mm should have a tibial tubercle transfer, in addition to lateral release

Purpose of the study: To develop a new treatment algorithm for patients with chronic anterior knee pain based on kinematic patella tracking MR imaging. Methods and Results: Patients with anterior knee pain of more than one year duration and not responding to non-operative treatment, underwent kinematic MRI study. The provocative test was performed with the conventional MRI scanner and the patient extending the knee against resistance, the resistance provided by inflated beach ball. A retrospective analysis was done of first seventy patients, who had undergone this scanning technique. On the imaging films, four measurements were made. They were patella subluxation, tilt, cartilage thickness and the Tibial Tubercle Trochlear distance (TTD). Patellar subluxation was classified as mild, moderate and severe. We found that a Tibial Tubercle Trochlea distance of 18mm had a specifity of 100% and a sensitivity of 89% for severe maltracking. Conclusion: Kinematic MR Imaging is a useful investigation before considering operative treatment for patients with chronic anterior knee pain. Based on our study, we conclude that those patients with moderate lateral maltracking with a TTD< 18 mm should be offered lateral release and those with severe maltracking and TTD> 18mm should have a tibial tubercle transfer, in addition to lateral release

To share our results following Medial Patellofemoral ligament (MPFL) reconstruction for patellar instability problems using ipsilateral semitendinosus graft anchored to the patella and the medial femoral condyle using biotenodesis screws. Study design and methods: 35 patients were assessed with a mean follow up of 18 months. All patients had preoperative true lateral knee x-ray, MRI or CT scan to look at trochlear dysplasia and the sulcus tuberosity distance. They all under went MPFL reconstruction using ipsilateral semitendinosus tendon. Two patients had sulcus tuberosity distance greater than 20 mm and they under went a tibial tubercle transfer in addition. Two patients had trochlear dysplasia and hence a trochlearplasty was also done. In skeletally mature patients the hamstrings tendon were anchored to the medial side of the patella in a 5×15mm blind tunnel using biotenodesis screw. This significantly reduces the risk of having patella fracture. All patients were treated by the same surgeon and assessments were performed by a different surgeon based on kujala scores and tegner scores. Results: Symptom relief was noted in all patients with in 3 months. No patient had patella dislocation or fracture after this procedure. They all had full range of movements and their kujala scores and tegner scores were good to excellent. Conclusion: MPFL reconstruction using hamstrings tendon anchored to the medial side of the patella and femur using biotenodesis screw gave a good result clinically and is associated with fewer complications including patellar fractures

Recurrent patellar instability and anterior knee pain is a common problem after patellar dislocation. The medial patellofemoral ligament (MPFL) which contributes 40–80% of the total restraining forces is either attenuated or ruptured in these patients. Various techniques have been described in reconstructing this MPFL using hamstrings tendons. We wish to share our experience in treating these patients using ipsilateral semitendinosus tendon anchored to the medial femoral condyle and medial side of the patella using biotenodesis screws. Study design and methods: 15 patients were assessed with a mean follow up of 12 months. All patients had pre-operative true lateral knee x-ray, MRI or CT scan to look at trochlear dysplasia and the sulcus tuberosity distance. They all under went MPFL reconstruction using ipsilateral semitendinosus tendon. Two patients had sulcus tuberosity distance greater than 20 mm and they under went a tibial tubercle transfer in addition. Two patients had trochlear dysplasia and hence a trochleaplasty was also done. In skeletally mature patients the hamstrings tendon was anchored to the medial side of the patella in a 5x15mm blind tunnel using biotenodesis screw. This significantly reduces the risk of having patella fracture. In. children the graft was sutures to the soft tissues along the medial side of the patella and the medial femoral condyle. All patients were treated by the same surgeon and assessments were performed by a different surgeon based . on Kujala scores and Tegner scores. Results: Symptom relief was noted in all patients with in 3 months. No patient had patella dislocation or fracture after this procedure. They all had full range of movements and their Kujala scores and Tegner scores were good to excellent. Conclusion: MPFL reconstruction using hamstrings tendon anchored to the medial side of the patella and femur using biotenodesis screw gave a good result clinically and is associated with fewer complications including patellar fractures

Background: Symptomatic patellofemoral osteoarthritis is a challenge to the orthopaedic surgeon. In comparison to Total Knee Arthroplasty (TKA), little has been written about unicompartmental patellofemoral arthroplasty. Although, recent reports have shown more promise, the procedure has not gained wide acceptance. Materials and Methods: We present the outcome of 23 unicompartmental patellofemoral arthroplasties on 19 patients performed in a district general hospital in the UK. The procedures were performed by a single surgeon (RSG), with a special interest in knee surgery. All the patients had failed a trial of non-operative treatment which included non-steroidal anti-inflammatory analgesia and physiotherapy. Some knees had undergone previous surgical procedures including arthroscopy (12), carbon fibre patch implantation (5), tibial tubercle transfer (1), lateral release (1), medial release (1) and excision of patellar bursa (1). Multiple arthroscopies had been performed on 4 knees. The arthroplasty was performed via an anterior midline incision and medial parapatellar approach. All patients received Leicester Patellofemoral Prosthesis (Corin). One patient had a revision procedure following a failed PFJR performed elsewhere. The age of the patient at the time of operation ranged from 31–68 years (Mean age 50.3 years). The duration of follow-up was 6 months to 88 months (Mean 36 months). The results were evaluated using the Oxford Knee Score. Results: One patellofemoral arthroplasty was converted to TKA after 41 months. There was no infection or loosening of the components in any patient. All patients reported relief of post-operative discomfort by 6 months except for one patient who developed hypersensitive skin lateral to the scar at 6 months. All patients said that their knees were significantly better after the procedure. Oxford Knee Scores ranged from 17 to 54 (Median 29). All except one patient reported that they would to undergo the procedure on their other knee (unilateral cases) and would recommend the procedure to friends/family. Conclusion: The early and medium term results of uni-compartmental patellofemoral arthroplasty in our study are encouraging with patients reporting significant improvement in knee symptoms. We feel that careful patient selection and meticulous attention to surgical detail contribute to better outcomes

Aims

In the UK, the agricultural, military, and construction sectors have stringent rules about the use of hearing protection due to the risk of noise-induced hearing loss. Orthopaedic staff may also be at risk due to the use of power tools. The UK Health and Safety Executive (HSE) have clear standards as to what are deemed acceptable occupational levels of noise on A-weighted and C-weighted scales. The aims of this review were to assess the current evidence on the testing of exposure to noise in orthopaedic operating theatres to see if it exceeds these regulations.

Patellar instability most frequently presents during adolescence. Congenital and infantile dislocation of the patella is a distinct entity from adolescent instability and measurable abnormalities may be present at birth. In the normal patellofemoral joint an increase in quadriceps angle and patellar height are matched by an increase in trochlear depth as the joint matures. Adolescent instability may herald a lifelong condition leading to chronic disability and arthritis.

Restoring normal anatomy by trochleoplasty, tibial tubercle transfer or medial patellofemoral ligament (MPFL) reconstruction in the young adult prevents further instability. Although these techniques are proven in the young adult, they may cause growth arrest and deformity where the physis is open. A vigorous non-operative strategy may permit delay of surgery until growth is complete. Where non-operative treatment has failed a modified MPFL reconstruction may be performed to maintain stability until physeal closure permits anatomical reconstruction. If significant growth remains an extraosseous reconstruction of the MPFL may impart the lowest risk to the physis. If minor growth remains image intensifier guided placement of femoral intraosseous fixation may impart a small, but acceptable, risk to the physis.

This paper presents and discusses the literature relating to adolescent instability and provides a framework for management of these patients.

Cite this article: Bone Joint J 2017;99-B:159–70.

Aims

The aim of this study was to examine the results of revision total knee arthroplasty (TKA) undertaken for stiffness in the absence of sepsis or loosening.